Merge branch 'i2c/for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux

Pull i2c changes from Wolfram Sang:

 - an arbitration driver.  While the driver is quite simple, it caused
   discussion if we need additional arbitration on top of the one
   specified in the I2C standard.  Conclusion is that I accept a few
   generic mechanisms, but not very specific ones.

 - the core lost the detach_adapter() call.  It has no users anymore and
   was in the way for other cleanups.  attach_adapter() is sadly still
   there since there are users waiting to be converted.

 - the core gained a bus recovery infrastructure.  I2C defines a way to
   recover if the data line is stalled.  This mechanism is now in the
   core and drivers can now pass some data to make use of it.

 - bigger driver cleanups for designware, s3c2410

 - removing superfluous refcounting from drivers

 - removing Ben Dooks as second maintainer due to inactivity.  Thanks
   for all your work so far, Ben!

 - bugfixes, feature additions, devicetree fixups, simplifications...

* 'i2c/for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (38 commits)
  i2c: xiic: must always write 16-bit words to TX_FIFO
  i2c: octeon: use HZ in timeout value
  i2c: octeon: Fix i2c fail problem when a process is terminated by a signal
  i2c: designware-pci: drop superfluous {get|put}_device
  i2c: designware-plat: drop superfluous {get|put}_device
  i2c: davinci: drop superfluous {get|put}_device
  MAINTAINERS: Ben Dooks is inactive regarding I2C
  i2c: mux: Add i2c-arb-gpio-challenge 'mux' driver
  i2c: at91: convert to dma_request_slave_channel_compat()
  i2c: mxs: do error checking and handling in PIO mode
  i2c: mxs: remove races in PIO code
  i2c-designware: switch to use runtime PM autosuspend
  i2c-designware: use usleep_range() in the busy-loop
  i2c-designware: enable/disable the controller properly
  i2c-designware: use dynamic adapter numbering on Lynxpoint
  i2c-designware-pci: use managed functions pcim_* and devm_*
  i2c-designware-pci: use dev_err() instead of printk()
  i2c-designware: move to managed functions (devm_*)
  i2c: remove CONFIG_HOTPLUG ifdefs
  i2c: s3c2410: Add SMBus emulation for block read
  ...

Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.txt

+GPIO-based I2C Arbitration Using a Challenge & Response Mechanism
+=================================================================
+This uses GPIO lines and a challenge & response mechanism to arbitrate who is
+the master of an I2C bus in a multimaster situation.
+
+In many cases using GPIOs to arbitrate is not needed and a design can use
+the standard I2C multi-master rules.  Using GPIOs is generally useful in
+the case where there is a device on the bus that has errata and/or bugs
+that makes standard multimaster mode not feasible.
+
+
+Algorithm:
+
+All masters on the bus have a 'bus claim' line which is an output that the
+others can see. These are all active low with pull-ups enabled.  We'll
+describe these lines as:
+
+- OUR_CLAIM: output from us signaling to other hosts that we want the bus
+- THEIR_CLAIMS: output from others signaling that they want the bus
+
+The basic algorithm is to assert your line when you want the bus, then make
+sure that the other side doesn't want it also.  A detailed explanation is best
+done with an example.
+
+Let's say we want to claim the bus.  We:
+1. Assert OUR_CLAIM.
+2. Waits a little bit for the other sides to notice (slew time, say 10
+   microseconds).
+3. Check THEIR_CLAIMS.  If none are asserted then the we have the bus and we are
+   done.
+4. Otherwise, wait for a few milliseconds and see if THEIR_CLAIMS are released.
+5. If not, back off, release the claim and wait for a few more milliseconds.
+6. Go back to 1 (until retry time has expired).
+
+
+Required properties:
+- compatible: i2c-arb-gpio-challenge
+- our-claim-gpio: The GPIO that we use to claim the bus.
+- their-claim-gpios: The GPIOs that the other sides use to claim the bus.
+  Note that some implementations may only support a single other master.
+- Standard I2C mux properties. See mux.txt in this directory.
+- Single I2C child bus node at reg 0. See mux.txt in this directory.
+
+Optional properties:
+- slew-delay-us: microseconds to wait for a GPIO to go high. Default is 10 us.
+- wait-retry-us: we'll attempt another claim after this many microseconds.
+    Default is 3000 us.
+- wait-free-us: we'll give up after this many microseconds. Default is 50000 us.
+
+
+Example:
+	i2c@12CA0000 {
+		compatible = "acme,some-i2c-device";
+		#address-cells = <1>;
+		#size-cells = <0>;
+	};
+
+	i2c-arbitrator {
+		compatible = "i2c-arb-gpio-challenge";
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		i2c-parent = <&{/i2c@12CA0000}>;
+
+		our-claim-gpio = <&gpf0 3 1>;
+		their-claim-gpios = <&gpe0 4 1>;
+		slew-delay-us = <10>;
+		wait-retry-us = <3000>;
+		wait-free-us = <50000>;
+
+		i2c@0 {
+			reg = <0>;
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			i2c@52 {
+				// Normal I2C device
+			};
+		};
+	};

MAINTAINERS

@@ -3919,7 +3919,6 @@ F:	drivers/i2c/i2c-stub.c
 
 I2C SUBSYSTEM
 M:	Wolfram Sang <wsa@the-dreams.de>
-M:	"Ben Dooks (embedded platforms)" <ben-linux@fluff.org>
 L:	linux-i2c@vger.kernel.org
 W:	http://i2c.wiki.kernel.org/
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux.git

arch/arm/mach-s3c24xx/mach-rx1950.c

@@ -56,7 +56,6 @@
 #include <plat/cpu.h>
 #include <plat/devs.h>
 #include <plat/pm.h>
-#include <plat/regs-iic.h>
 #include <plat/regs-serial.h>
 
 #include "common.h"

arch/arm/mach-tegra/tegra.c

@@ -31,8 +31,6 @@
 #include <linux/pda_power.h>
 #include <linux/platform_data/tegra_usb.h>
 #include <linux/io.h>
-#include <linux/i2c.h>
-#include <linux/i2c-tegra.h>
 #include <linux/slab.h>
 #include <linux/sys_soc.h>
 #include <linux/usb/tegra_usb_phy.h>

arch/arm/plat-samsung/devs.c

@@ -63,7 +63,6 @@
 #include <linux/platform_data/usb-s3c2410_udc.h>
 #include <linux/platform_data/usb-ohci-s3c2410.h>
 #include <plat/usb-phy.h>
-#include <plat/regs-iic.h>
 #include <plat/regs-serial.h>
 #include <plat/regs-spi.h>
 #include <linux/platform_data/spi-s3c64xx.h>

arch/arm/plat-samsung/include/plat/regs-iic.h

-/* arch/arm/mach-s3c2410/include/mach/regs-iic.h
- *
- * Copyright (c) 2004 Simtec Electronics <linux@simtec.co.uk>
- *		http://www.simtec.co.uk/products/SWLINUX/
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * S3C2410 I2C Controller
-*/
-
-#ifndef __ASM_ARCH_REGS_IIC_H
-#define __ASM_ARCH_REGS_IIC_H __FILE__
-
-/* see s3c2410x user guide, v1.1, section 9 (p447) for more info */
-
-#define S3C2410_IICREG(x) (x)
-
-#define S3C2410_IICCON    S3C2410_IICREG(0x00)
-#define S3C2410_IICSTAT   S3C2410_IICREG(0x04)
-#define S3C2410_IICADD    S3C2410_IICREG(0x08)
-#define S3C2410_IICDS     S3C2410_IICREG(0x0C)
-#define S3C2440_IICLC	  S3C2410_IICREG(0x10)
-
-#define S3C2410_IICCON_ACKEN		(1<<7)
-#define S3C2410_IICCON_TXDIV_16		(0<<6)
-#define S3C2410_IICCON_TXDIV_512	(1<<6)
-#define S3C2410_IICCON_IRQEN		(1<<5)
-#define S3C2410_IICCON_IRQPEND		(1<<4)
-#define S3C2410_IICCON_SCALE(x)		((x)&15)
-#define S3C2410_IICCON_SCALEMASK	(0xf)
-
-#define S3C2410_IICSTAT_MASTER_RX	(2<<6)
-#define S3C2410_IICSTAT_MASTER_TX	(3<<6)
-#define S3C2410_IICSTAT_SLAVE_RX	(0<<6)
-#define S3C2410_IICSTAT_SLAVE_TX	(1<<6)
-#define S3C2410_IICSTAT_MODEMASK	(3<<6)
-
-#define S3C2410_IICSTAT_START		(1<<5)
-#define S3C2410_IICSTAT_BUSBUSY		(1<<5)
-#define S3C2410_IICSTAT_TXRXEN		(1<<4)
-#define S3C2410_IICSTAT_ARBITR		(1<<3)
-#define S3C2410_IICSTAT_ASSLAVE		(1<<2)
-#define S3C2410_IICSTAT_ADDR0		(1<<1)
-#define S3C2410_IICSTAT_LASTBIT		(1<<0)
-
-#define S3C2410_IICLC_SDA_DELAY0	(0 << 0)
-#define S3C2410_IICLC_SDA_DELAY5	(1 << 0)
-#define S3C2410_IICLC_SDA_DELAY10	(2 << 0)
-#define S3C2410_IICLC_SDA_DELAY15	(3 << 0)
-#define S3C2410_IICLC_SDA_DELAY_MASK	(3 << 0)
-
-#define S3C2410_IICLC_FILTER_ON		(1<<2)
-
-#endif /* __ASM_ARCH_REGS_IIC_H */

drivers/gpu/drm/gma500/oaktrail_hdmi_i2c.c

@@ -319,8 +319,7 @@ void oaktrail_hdmi_i2c_exit(struct pci_dev *dev)
 	struct hdmi_i2c_dev *i2c_dev;
 
 	hdmi_dev = pci_get_drvdata(dev);
-	if (i2c_del_adapter(&oaktrail_hdmi_i2c_adapter))
-		DRM_DEBUG_DRIVER("Failed to delete hdmi-i2c adapter\n");
+	i2c_del_adapter(&oaktrail_hdmi_i2c_adapter);
 
 	i2c_dev = hdmi_dev->i2c_dev;
 	kfree(i2c_dev);

drivers/i2c/busses/i2c-amd756-s4882.c

@@ -169,11 +169,7 @@ static int __init amd756_s4882_init(void)
 	}
 
 	/* Unregister physical bus */
-	error = i2c_del_adapter(&amd756_smbus);
-	if (error) {
-		dev_err(&amd756_smbus.dev, "Physical bus removal failed\n");
-		goto ERROR0;
-	}
+	i2c_del_adapter(&amd756_smbus);
 
 	printk(KERN_INFO "Enabling SMBus multiplexing for Tyan S4882\n");
 	/* Define the 5 virtual adapters and algorithms structures */

drivers/i2c/busses/i2c-at91.c

@@ -603,15 +603,18 @@ static const struct of_device_id atmel_twi_dt_ids[] = {
 	}
 };
 MODULE_DEVICE_TABLE(of, atmel_twi_dt_ids);
-#else
-#define atmel_twi_dt_ids NULL
 #endif
 
-static bool filter(struct dma_chan *chan, void *slave)
+static bool filter(struct dma_chan *chan, void *pdata)
 {
-	struct at_dma_slave *sl = slave;
+	struct at91_twi_pdata *sl_pdata = pdata;
+	struct at_dma_slave *sl;
+
+	if (!sl_pdata)
+		return false;
 
-	if (sl->dma_dev == chan->device->dev) {
+	sl = &sl_pdata->dma_slave;
+	if (sl && (sl->dma_dev == chan->device->dev)) {
 		chan->private = sl;
 		return true;
 	} else {
@@ -622,11 +625,10 @@ static bool filter(struct dma_chan *chan, void *slave)
 static int at91_twi_configure_dma(struct at91_twi_dev *dev, u32 phy_addr)
 {
 	int ret = 0;
-	struct at_dma_slave *sdata;
+	struct at91_twi_pdata *pdata = dev->pdata;
 	struct dma_slave_config slave_config;
 	struct at91_twi_dma *dma = &dev->dma;
-
-	sdata = &dev->pdata->dma_slave;
+	dma_cap_mask_t mask;
 
 	memset(&slave_config, 0, sizeof(slave_config));
 	slave_config.src_addr = (dma_addr_t)phy_addr + AT91_TWI_RHR;
@@ -637,25 +639,22 @@ static int at91_twi_configure_dma(struct at91_twi_dev *dev, u32 phy_addr)
 	slave_config.dst_maxburst = 1;
 	slave_config.device_fc = false;
 
-	if (sdata && sdata->dma_dev) {
-		dma_cap_mask_t mask;
+	dma_cap_zero(mask);
+	dma_cap_set(DMA_SLAVE, mask);
 
-		dma_cap_zero(mask);
-		dma_cap_set(DMA_SLAVE, mask);
-		dma->chan_tx = dma_request_channel(mask, filter, sdata);
-		if (!dma->chan_tx) {
-			dev_err(dev->dev, "no DMA channel available for tx\n");
-			ret = -EBUSY;
-			goto error;
-		}
-		dma->chan_rx = dma_request_channel(mask, filter, sdata);
-		if (!dma->chan_rx) {
-			dev_err(dev->dev, "no DMA channel available for rx\n");
-			ret = -EBUSY;
-			goto error;
-		}
-	} else {
-		ret = -EINVAL;
+	dma->chan_tx = dma_request_slave_channel_compat(mask, filter, pdata,
+							dev->dev, "tx");
+	if (!dma->chan_tx) {
+		dev_err(dev->dev, "can't get a DMA channel for tx\n");
+		ret = -EBUSY;
+		goto error;
+	}
+
+	dma->chan_rx = dma_request_slave_channel_compat(mask, filter, pdata,
+							dev->dev, "rx");
+	if (!dma->chan_rx) {
+		dev_err(dev->dev, "can't get a DMA channel for rx\n");
+		ret = -EBUSY;
 		goto error;
 	}
 
@@ -785,12 +784,11 @@ static int at91_twi_probe(struct platform_device *pdev)
 static int at91_twi_remove(struct platform_device *pdev)
 {
 	struct at91_twi_dev *dev = platform_get_drvdata(pdev);
-	int rc;
 
-	rc = i2c_del_adapter(&dev->adapter);
+	i2c_del_adapter(&dev->adapter);
 	clk_disable_unprepare(dev->clk);
 
-	return rc;
+	return 0;
 }
 
 #ifdef CONFIG_PM
@@ -828,7 +826,7 @@ static struct platform_driver at91_twi_driver = {
 	.driver		= {
 		.name	= "at91_i2c",
 		.owner	= THIS_MODULE,
-		.of_match_table = atmel_twi_dt_ids,
+		.of_match_table = of_match_ptr(atmel_twi_dt_ids),
 		.pm	= at91_twi_pm_ops,
 	},
 };

drivers/i2c/busses/i2c-cbus-gpio.c

@@ -206,7 +206,9 @@ static int cbus_i2c_remove(struct platform_device *pdev)
 {
 	struct i2c_adapter *adapter = platform_get_drvdata(pdev);
 
-	return i2c_del_adapter(adapter);
+	i2c_del_adapter(adapter);
+
+	return 0;
 }
 
 static int cbus_i2c_probe(struct platform_device *pdev)

drivers/i2c/busses/i2c-davinci.c

@@ -137,7 +137,7 @@ static inline u16 davinci_i2c_read_reg(struct davinci_i2c_dev *i2c_dev, int reg)
 }
 
 /* Generate a pulse on the i2c clock pin. */
-static void generic_i2c_clock_pulse(unsigned int scl_pin)
+static void davinci_i2c_clock_pulse(unsigned int scl_pin)
 {
 	u16 i;
 
@@ -155,7 +155,7 @@ static void generic_i2c_clock_pulse(unsigned int scl_pin)
 /* This routine does i2c bus recovery as specified in the
  * i2c protocol Rev. 03 section 3.16 titled "Bus clear"
  */
-static void i2c_recover_bus(struct davinci_i2c_dev *dev)
+static void davinci_i2c_recover_bus(struct davinci_i2c_dev *dev)
 {
 	u32 flag = 0;
 	struct davinci_i2c_platform_data *pdata = dev->pdata;
@@ -166,7 +166,7 @@ static void i2c_recover_bus(struct davinci_i2c_dev *dev)
 	flag |=  DAVINCI_I2C_MDR_NACK;
 	/* write the data into mode register */
 	davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
-	generic_i2c_clock_pulse(pdata->scl_pin);
+	davinci_i2c_clock_pulse(pdata->scl_pin);
 	/* Send STOP */
 	flag = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
 	flag |= DAVINCI_I2C_MDR_STP;
@@ -289,7 +289,7 @@ static int i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev *dev,
 				return -ETIMEDOUT;
 			} else {
 				to_cnt = 0;
-				i2c_recover_bus(dev);
+				davinci_i2c_recover_bus(dev);
 				i2c_davinci_init(dev);
 			}
 		}
@@ -379,7 +379,7 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
 						      dev->adapter.timeout);
 	if (r == 0) {
 		dev_err(dev->dev, "controller timed out\n");
-		i2c_recover_bus(dev);
+		davinci_i2c_recover_bus(dev);
 		i2c_davinci_init(dev);
 		dev->buf_len = 0;
 		return -ETIMEDOUT;
@@ -643,7 +643,7 @@ static int davinci_i2c_probe(struct platform_device *pdev)
 {
 	struct davinci_i2c_dev *dev;
 	struct i2c_adapter *adap;
-	struct resource *mem, *irq, *ioarea;
+	struct resource *mem, *irq;
 	int r;
 
 	/* NOTE: driver uses the static register mapping */
@@ -659,24 +659,18 @@ static int davinci_i2c_probe(struct platform_device *pdev)
 		return -ENODEV;
 	}
 
-	ioarea = request_mem_region(mem->start, resource_size(mem),
-				    pdev->name);
-	if (!ioarea) {
-		dev_err(&pdev->dev, "I2C region already claimed\n");
-		return -EBUSY;
-	}
-
-	dev = kzalloc(sizeof(struct davinci_i2c_dev), GFP_KERNEL);
+	dev = devm_kzalloc(&pdev->dev, sizeof(struct davinci_i2c_dev),
+			GFP_KERNEL);
 	if (!dev) {
-		r = -ENOMEM;
-		goto err_release_region;
+		dev_err(&pdev->dev, "Memory allocation failed\n");
+		return -ENOMEM;
 	}
 
 	init_completion(&dev->cmd_complete);
 #ifdef CONFIG_CPU_FREQ
 	init_completion(&dev->xfr_complete);
 #endif
-	dev->dev = get_device(&pdev->dev);
+	dev->dev = &pdev->dev;
 	dev->irq = irq->start;
 	dev->pdata = dev->dev->platform_data;
 	platform_set_drvdata(pdev, dev);
@@ -686,10 +680,9 @@ static int davinci_i2c_probe(struct platform_device *pdev)
 
 		dev->pdata = devm_kzalloc(&pdev->dev,
 			sizeof(struct davinci_i2c_platform_data), GFP_KERNEL);
-		if (!dev->pdata) {
-			r = -ENOMEM;
-			goto err_free_mem;
-		}
+		if (!dev->pdata)
+			return -ENOMEM;
+
 		memcpy(dev->pdata, &davinci_i2c_platform_data_default,
 			sizeof(struct davinci_i2c_platform_data));
 		if (!of_property_read_u32(pdev->dev.of_node, "clock-frequency",
@@ -699,22 +692,21 @@ static int davinci_i2c_probe(struct platform_device *pdev)
 		dev->pdata = &davinci_i2c_platform_data_default;
 	}
 
-	dev->clk = clk_get(&pdev->dev, NULL);
-	if (IS_ERR(dev->clk)) {
-		r = -ENODEV;
-		goto err_free_mem;
-	}
+	dev->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(dev->clk))
+		return -ENODEV;
 	clk_prepare_enable(dev->clk);
 
-	dev->base = ioremap(mem->start, resource_size(mem));
-	if (!dev->base) {
-		r = -EBUSY;
-		goto err_mem_ioremap;
+	dev->base = devm_ioremap_resource(&pdev->dev, mem);
+	if (IS_ERR(dev->base)) {
+		r = PTR_ERR(dev->base);
+		goto err_unuse_clocks;
 	}
 
 	i2c_davinci_init(dev);
 
-	r = request_irq(dev->irq, i2c_davinci_isr, 0, pdev->name, dev);
+	r = devm_request_irq(&pdev->dev, dev->irq, i2c_davinci_isr, 0,
+			pdev->name, dev);
 	if (r) {
 		dev_err(&pdev->dev, "failure requesting irq %i\n", dev->irq);
 		goto err_unuse_clocks;
@@ -723,7 +715,7 @@ static int davinci_i2c_probe(struct platform_device *pdev)
 	r = i2c_davinci_cpufreq_register(dev);
 	if (r) {
 		dev_err(&pdev->dev, "failed to register cpufreq\n");
-		goto err_free_irq;
+		goto err_unuse_clocks;
 	}
 
 	adap = &dev->adapter;
@@ -740,50 +732,31 @@ static int davinci_i2c_probe(struct platform_device *pdev)
 	r = i2c_add_numbered_adapter(adap);
 	if (r) {
 		dev_err(&pdev->dev, "failure adding adapter\n");
-		goto err_free_irq;
+		goto err_unuse_clocks;
 	}
 	of_i2c_register_devices(adap);
 
 	return 0;
 
-err_free_irq:
-	free_irq(dev->irq, dev);
 err_unuse_clocks:
-	iounmap(dev->base);
-err_mem_ioremap:
 	clk_disable_unprepare(dev->clk);
-	clk_put(dev->clk);
 	dev->clk = NULL;
-err_free_mem:
-	put_device(&pdev->dev);
-	kfree(dev);
-err_release_region:
-	release_mem_region(mem->start, resource_size(mem));
-
 	return r;
 }
 
 static int davinci_i2c_remove(struct platform_device *pdev)
 {
 	struct davinci_i2c_dev *dev = platform_get_drvdata(pdev);
-	struct resource *mem;
 
 	i2c_davinci_cpufreq_deregister(dev);
 
 	i2c_del_adapter(&dev->adapter);
-	put_device(&pdev->dev);
 
 	clk_disable_unprepare(dev->clk);
-	clk_put(dev->clk);
 	dev->clk = NULL;
 
 	davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, 0);
-	free_irq(dev->irq, dev);
-	iounmap(dev->base);
-	kfree(dev);
 
-	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	release_mem_region(mem->start, resource_size(mem));
 	return 0;
 }
 

drivers/i2c/busses/i2c-designware-core.c

@@ -68,6 +68,7 @@
 #define DW_IC_TXFLR		0x74
 #define DW_IC_RXFLR		0x78
 #define DW_IC_TX_ABRT_SOURCE	0x80
+#define DW_IC_ENABLE_STATUS	0x9c
 #define DW_IC_COMP_PARAM_1	0xf4
 #define DW_IC_COMP_TYPE		0xfc
 #define DW_IC_COMP_TYPE_VALUE	0x44570140
@@ -248,6 +249,27 @@ static u32 i2c_dw_scl_lcnt(u32 ic_clk, u32 tLOW, u32 tf, int offset)
 	return ((ic_clk * (tLOW + tf) + 5000) / 10000) - 1 + offset;
 }
 
+static void __i2c_dw_enable(struct dw_i2c_dev *dev, bool enable)
+{
+	int timeout = 100;
+
+	do {
+		dw_writel(dev, enable, DW_IC_ENABLE);
+		if ((dw_readl(dev, DW_IC_ENABLE_STATUS) & 1) == enable)
+			return;
+
+		/*
+		 * Wait 10 times the signaling period of the highest I2C
+		 * transfer supported by the driver (for 400KHz this is
+		 * 25us) as described in the DesignWare I2C databook.
+		 */
+		usleep_range(25, 250);
+	} while (timeout--);
+
+	dev_warn(dev->dev, "timeout in %sabling adapter\n",
+		 enable ? "en" : "dis");
+}
+
 /**
  * i2c_dw_init() - initialize the designware i2c master hardware
  * @dev: device private data
@@ -278,7 +300,7 @@ int i2c_dw_init(struct dw_i2c_dev *dev)
 	}
 
 	/* Disable the adapter */
-	dw_writel(dev, 0, DW_IC_ENABLE);
+	__i2c_dw_enable(dev, false);
 
 	/* set standard and fast speed deviders for high/low periods */
 
@@ -333,7 +355,7 @@ static int i2c_dw_wait_bus_not_busy(struct dw_i2c_dev *dev)
 			return -ETIMEDOUT;
 		}
 		timeout--;
-		mdelay(1);
+		usleep_range(1000, 1100);
 	}
 
 	return 0;
@@ -345,7 +367,7 @@ static void i2c_dw_xfer_init(struct dw_i2c_dev *dev)
 	u32 ic_con;
 
 	/* Disable the adapter */
-	dw_writel(dev, 0, DW_IC_ENABLE);
+	__i2c_dw_enable(dev, false);
 
 	/* set the slave (target) address */
 	dw_writel(dev, msgs[dev->msg_write_idx].addr, DW_IC_TAR);
@@ -359,7 +381,7 @@ static void i2c_dw_xfer_init(struct dw_i2c_dev *dev)
 	dw_writel(dev, ic_con, DW_IC_CON);
 
 	/* Enable the adapter */
-	dw_writel(dev, 1, DW_IC_ENABLE);
+	__i2c_dw_enable(dev, true);
 
 	/* Enable interrupts */
 	dw_writel(dev, DW_IC_INTR_DEFAULT_MASK, DW_IC_INTR_MASK);
@@ -565,7 +587,7 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 	/* no error */
 	if (likely(!dev->cmd_err)) {
 		/* Disable the adapter */
-		dw_writel(dev, 0, DW_IC_ENABLE);
+		__i2c_dw_enable(dev, false);
 		ret = num;
 		goto done;
 	}
@@ -578,7 +600,8 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 	ret = -EIO;
 
 done:
-	pm_runtime_put(dev->dev);
+	pm_runtime_mark_last_busy(dev->dev);
+	pm_runtime_put_autosuspend(dev->dev);
 	mutex_unlock(&dev->lock);
 
 	return ret;
@@ -700,7 +723,7 @@ EXPORT_SYMBOL_GPL(i2c_dw_isr);
 void i2c_dw_enable(struct dw_i2c_dev *dev)
 {
        /* Enable the adapter */
-	dw_writel(dev, 1, DW_IC_ENABLE);
+	__i2c_dw_enable(dev, true);
 }
 EXPORT_SYMBOL_GPL(i2c_dw_enable);
 
@@ -713,7 +736,7 @@ EXPORT_SYMBOL_GPL(i2c_dw_is_enabled);
 void i2c_dw_disable(struct dw_i2c_dev *dev)
 {
 	/* Disable controller */
-	dw_writel(dev, 0, DW_IC_ENABLE);
+	__i2c_dw_enable(dev, false);
 
 	/* Disable all interupts */
 	dw_writel(dev, 0, DW_IC_INTR_MASK);

drivers/i2c/busses/i2c-designware-pcidrv.c

@@ -208,68 +208,45 @@ static u32 i2c_dw_get_clk_rate_khz(struct dw_i2c_dev *dev)
 }
 
 static int i2c_dw_pci_probe(struct pci_dev *pdev,
-const struct pci_device_id *id)
+			    const struct pci_device_id *id)
 {
 	struct dw_i2c_dev *dev;
 	struct i2c_adapter *adap;
-	unsigned long start, len;
-	void __iomem *base;
 	int r;
 	struct  dw_pci_controller *controller;
 
 	if (id->driver_data >= ARRAY_SIZE(dw_pci_controllers)) {
-		printk(KERN_ERR "dw_i2c_pci_probe: invalid driver data %ld\n",
+		dev_err(&pdev->dev, "%s: invalid driver data %ld\n", __func__,
 			id->driver_data);
 		return -EINVAL;
 	}
 
 	controller = &dw_pci_controllers[id->driver_data];
 
-	r = pci_enable_device(pdev);
+	r = pcim_enable_device(pdev);
 	if (r) {
 		dev_err(&pdev->dev, "Failed to enable I2C PCI device (%d)\n",
 			r);
-		goto exit;
+		return r;
 	}
 
-	/* Determine the address of the I2C area */
-	start = pci_resource_start(pdev, 0);
-	len = pci_resource_len(pdev, 0);
-	if (!start || len == 0) {
-		dev_err(&pdev->dev, "base address not set\n");
-		r = -ENODEV;
-		goto exit;
-	}
-
-	r = pci_request_region(pdev, 0, DRIVER_NAME);
+	r = pcim_iomap_regions(pdev, 1 << 0, pci_name(pdev));
 	if (r) {
-		dev_err(&pdev->dev, "failed to request I2C region "
-			"0x%lx-0x%lx\n", start,
-			(unsigned long)pci_resource_end(pdev, 0));
-		goto exit;
-	}
-
-	base = ioremap_nocache(start, len);
-	if (!base) {
 		dev_err(&pdev->dev, "I/O memory remapping failed\n");
-		r = -ENOMEM;
-		goto err_release_region;
+		return r;
 	}
 
-
-	dev = kzalloc(sizeof(struct dw_i2c_dev), GFP_KERNEL);
-	if (!dev) {
-		r = -ENOMEM;
-		goto err_release_region;
-	}
+	dev = devm_kzalloc(&pdev->dev, sizeof(struct dw_i2c_dev), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
 
 	init_completion(&dev->cmd_complete);
 	mutex_init(&dev->lock);
 	dev->clk = NULL;
 	dev->controller = controller;
 	dev->get_clk_rate_khz = i2c_dw_get_clk_rate_khz;
-	dev->base = base;
-	dev->dev = get_device(&pdev->dev);
+	dev->base = pcim_iomap_table(pdev)[0];
+	dev->dev = &pdev->dev;
 	dev->functionality =
 		I2C_FUNC_I2C |
 		I2C_FUNC_SMBUS_BYTE |
@@ -284,7 +261,7 @@ const struct pci_device_id *id)
 	dev->rx_fifo_depth = controller->rx_fifo_depth;
 	r = i2c_dw_init(dev);
 	if (r)
-		goto err_iounmap;
+		return r;
 
 	adap = &dev->adapter;
 	i2c_set_adapdata(adap, dev);
@@ -296,10 +273,11 @@ const struct pci_device_id *id)
 	snprintf(adap->name, sizeof(adap->name), "i2c-designware-pci-%d",
 		adap->nr);
 
-	r = request_irq(pdev->irq, i2c_dw_isr, IRQF_SHARED, adap->name, dev);
+	r = devm_request_irq(&pdev->dev, pdev->irq, i2c_dw_isr, IRQF_SHARED,
+			adap->name, dev);
 	if (r) {
 		dev_err(&pdev->dev, "failure requesting irq %i\n", dev->irq);
-		goto err_iounmap;
+		return r;
 	}
 
 	i2c_dw_disable_int(dev);
@@ -307,24 +285,14 @@ const struct pci_device_id *id)
 	r = i2c_add_numbered_adapter(adap);
 	if (r) {
 		dev_err(&pdev->dev, "failure adding adapter\n");
-		goto err_free_irq;
+		return r;
 	}
 
-	pm_runtime_put_noidle(&pdev->dev);
+	pm_runtime_set_autosuspend_delay(&pdev->dev, 1000);
+	pm_runtime_use_autosuspend(&pdev->dev);
 	pm_runtime_allow(&pdev->dev);
 
 	return 0;
-
-err_free_irq:
-	free_irq(pdev->irq, dev);
-err_iounmap:
-	iounmap(dev->base);
-	put_device(&pdev->dev);
-	kfree(dev);
-err_release_region:
-	pci_release_region(pdev, 0);
-exit:
-	return r;
 }
 
 static void i2c_dw_pci_remove(struct pci_dev *pdev)
@@ -336,11 +304,6 @@ static void i2c_dw_pci_remove(struct pci_dev *pdev)
 	pm_runtime_get_noresume(&pdev->dev);
 
 	i2c_del_adapter(&dev->adapter);
-	put_device(&pdev->dev);
-
-	free_irq(dev->irq, dev);
-	kfree(dev);
-	pci_release_region(pdev, 0);
 }
 
 /* work with hotplug and coldplug */

drivers/i2c/busses/i2c-designware-platdrv.c

@@ -56,20 +56,11 @@ static u32 i2c_dw_get_clk_rate_khz(struct dw_i2c_dev *dev)
 static int dw_i2c_acpi_configure(struct platform_device *pdev)
 {
 	struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
-	struct acpi_device *adev;
-	int busno, ret;
 
 	if (!ACPI_HANDLE(&pdev->dev))
 		return -ENODEV;
 
-	ret = acpi_bus_get_device(ACPI_HANDLE(&pdev->dev), &adev);
-	if (ret)
-		return -ENODEV;
-
 	dev->adapter.nr = -1;
-	if (adev->pnp.unique_id && !kstrtoint(adev->pnp.unique_id, 0, &busno))
-		dev->adapter.nr = busno;
-
 	dev->tx_fifo_depth = 32;
 	dev->rx_fifo_depth = 32;
 	return 0;
@@ -92,7 +83,7 @@ static int dw_i2c_probe(struct platform_device *pdev)
 {
 	struct dw_i2c_dev *dev;
 	struct i2c_adapter *adap;
-	struct resource *mem, *ioarea;
+	struct resource *mem;
 	int irq, r;
 
 	/* NOTE: driver uses the static register mapping */
@@ -108,32 +99,25 @@ static int dw_i2c_probe(struct platform_device *pdev)
 		return irq; /* -ENXIO */
 	}
 
-	ioarea = request_mem_region(mem->start, resource_size(mem),
-			pdev->name);
-	if (!ioarea) {
-		dev_err(&pdev->dev, "I2C region already claimed\n");
-		return -EBUSY;
-	}
+	dev = devm_kzalloc(&pdev->dev, sizeof(struct dw_i2c_dev), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
 
-	dev = kzalloc(sizeof(struct dw_i2c_dev), GFP_KERNEL);
-	if (!dev) {
-		r = -ENOMEM;
-		goto err_release_region;
-	}
+	dev->base = devm_ioremap_resource(&pdev->dev, mem);
+	if (IS_ERR(dev->base))
+		return PTR_ERR(dev->base);
 
 	init_completion(&dev->cmd_complete);
 	mutex_init(&dev->lock);
-	dev->dev = get_device(&pdev->dev);
+	dev->dev = &pdev->dev;
 	dev->irq = irq;
 	platform_set_drvdata(pdev, dev);
 
-	dev->clk = clk_get(&pdev->dev, NULL);
+	dev->clk = devm_clk_get(&pdev->dev, NULL);
 	dev->get_clk_rate_khz = i2c_dw_get_clk_rate_khz;
 
-	if (IS_ERR(dev->clk)) {
-		r = -ENODEV;
-		goto err_free_mem;
-	}
+	if (IS_ERR(dev->clk))
+		return PTR_ERR(dev->clk);
 	clk_prepare_enable(dev->clk);
 
 	dev->functionality =
@@ -146,13 +130,6 @@ static int dw_i2c_probe(struct platform_device *pdev)
 	dev->master_cfg =  DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE |
 		DW_IC_CON_RESTART_EN | DW_IC_CON_SPEED_FAST;
 
-	dev->base = ioremap(mem->start, resource_size(mem));
-	if (dev->base == NULL) {
-		dev_err(&pdev->dev, "failure mapping io resources\n");
-		r = -EBUSY;
-		goto err_unuse_clocks;
-	}
-
 	/* Try first if we can configure the device from ACPI */
 	r = dw_i2c_acpi_configure(pdev);
 	if (r) {
@@ -164,13 +141,14 @@ static int dw_i2c_probe(struct platform_device *pdev)
 	}
 	r = i2c_dw_init(dev);
 	if (r)
-		goto err_iounmap;
+		return r;
 
 	i2c_dw_disable_int(dev);
-	r = request_irq(dev->irq, i2c_dw_isr, IRQF_SHARED, pdev->name, dev);
+	r = devm_request_irq(&pdev->dev, dev->irq, i2c_dw_isr, IRQF_SHARED,
+			pdev->name, dev);
 	if (r) {
 		dev_err(&pdev->dev, "failure requesting irq %i\n", dev->irq);
-		goto err_iounmap;
+		return r;
 	}
 
 	adap = &dev->adapter;
@@ -186,57 +164,32 @@ static int dw_i2c_probe(struct platform_device *pdev)
 	r = i2c_add_numbered_adapter(adap);
 	if (r) {
 		dev_err(&pdev->dev, "failure adding adapter\n");
-		goto err_free_irq;
+		return r;
 	}
 	of_i2c_register_devices(adap);
 	acpi_i2c_register_devices(adap);
 
+	pm_runtime_set_autosuspend_delay(&pdev->dev, 1000);
+	pm_runtime_use_autosuspend(&pdev->dev);
 	pm_runtime_set_active(&pdev->dev);
 	pm_runtime_enable(&pdev->dev);
-	pm_runtime_put(&pdev->dev);
 
 	return 0;
-
-err_free_irq:
-	free_irq(dev->irq, dev);
-err_iounmap:
-	iounmap(dev->base);
-err_unuse_clocks:
-	clk_disable_unprepare(dev->clk);
-	clk_put(dev->clk);
-	dev->clk = NULL;
-err_free_mem:
-	put_device(&pdev->dev);
-	kfree(dev);
-err_release_region:
-	release_mem_region(mem->start, resource_size(mem));
-
-	return r;
 }
 
 static int dw_i2c_remove(struct platform_device *pdev)
 {
 	struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
-	struct resource *mem;
 
 	pm_runtime_get_sync(&pdev->dev);
 
 	i2c_del_adapter(&dev->adapter);
-	put_device(&pdev->dev);
-
-	clk_disable_unprepare(dev->clk);
-	clk_put(dev->clk);
-	dev->clk = NULL;
 
 	i2c_dw_disable(dev);
-	free_irq(dev->irq, dev);
-	kfree(dev);
 
 	pm_runtime_put(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 
-	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	release_mem_region(mem->start, resource_size(mem));
 	return 0;
 }
 

drivers/i2c/busses/i2c-gpio.c

@@ -85,23 +85,29 @@ static int i2c_gpio_getscl(void *data)
 	return gpio_get_value(pdata->scl_pin);
 }
 
-static int of_i2c_gpio_probe(struct device_node *np,
-			     struct i2c_gpio_platform_data *pdata)
+static int of_i2c_gpio_get_pins(struct device_node *np,
+				unsigned int *sda_pin, unsigned int *scl_pin)
 {
-	u32 reg;
-
 	if (of_gpio_count(np) < 2)
 		return -ENODEV;
 
-	pdata->sda_pin = of_get_gpio(np, 0);
-	pdata->scl_pin = of_get_gpio(np, 1);
+	*sda_pin = of_get_gpio(np, 0);
+	*scl_pin = of_get_gpio(np, 1);
 
-	if (!gpio_is_valid(pdata->sda_pin) || !gpio_is_valid(pdata->scl_pin)) {
+	if (!gpio_is_valid(*sda_pin) || !gpio_is_valid(*scl_pin)) {
 		pr_err("%s: invalid GPIO pins, sda=%d/scl=%d\n",
-		       np->full_name, pdata->sda_pin, pdata->scl_pin);
+		       np->full_name, *sda_pin, *scl_pin);
 		return -ENODEV;
 	}
 
+	return 0;
+}
+
+static void of_i2c_gpio_get_props(struct device_node *np,
+				  struct i2c_gpio_platform_data *pdata)
+{
+	u32 reg;
+
 	of_property_read_u32(np, "i2c-gpio,delay-us", &pdata->udelay);
 
 	if (!of_property_read_u32(np, "i2c-gpio,timeout-ms", &reg))
@@ -113,8 +119,6 @@ static int of_i2c_gpio_probe(struct device_node *np,
 		of_property_read_bool(np, "i2c-gpio,scl-open-drain");
 	pdata->scl_is_output_only =
 		of_property_read_bool(np, "i2c-gpio,scl-output-only");
-
-	return 0;
 }
 
 static int i2c_gpio_probe(struct platform_device *pdev)
@@ -123,31 +127,52 @@ static int i2c_gpio_probe(struct platform_device *pdev)
 	struct i2c_gpio_platform_data *pdata;
 	struct i2c_algo_bit_data *bit_data;
 	struct i2c_adapter *adap;
+	unsigned int sda_pin, scl_pin;
 	int ret;
 
-	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
-	if (!priv)
-		return -ENOMEM;
-	adap = &priv->adap;
-	bit_data = &priv->bit_data;
-	pdata = &priv->pdata;
-
+	/* First get the GPIO pins; if it fails, we'll defer the probe. */
 	if (pdev->dev.of_node) {
-		ret = of_i2c_gpio_probe(pdev->dev.of_node, pdata);
+		ret = of_i2c_gpio_get_pins(pdev->dev.of_node,
+					   &sda_pin, &scl_pin);
 		if (ret)
 			return ret;
 	} else {
 		if (!pdev->dev.platform_data)
 			return -ENXIO;
-		memcpy(pdata, pdev->dev.platform_data, sizeof(*pdata));
+		pdata = pdev->dev.platform_data;
+		sda_pin = pdata->sda_pin;
+		scl_pin = pdata->scl_pin;
 	}
 
-	ret = gpio_request(pdata->sda_pin, "sda");
-	if (ret)
+	ret = gpio_request(sda_pin, "sda");
+	if (ret) {
+		if (ret == -EINVAL)
+			ret = -EPROBE_DEFER;	/* Try again later */
 		goto err_request_sda;
-	ret = gpio_request(pdata->scl_pin, "scl");
-	if (ret)
+	}
+	ret = gpio_request(scl_pin, "scl");
+	if (ret) {
+		if (ret == -EINVAL)
+			ret = -EPROBE_DEFER;	/* Try again later */
 		goto err_request_scl;
+	}
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv) {
+		ret = -ENOMEM;
+		goto err_add_bus;
+	}
+	adap = &priv->adap;
+	bit_data = &priv->bit_data;
+	pdata = &priv->pdata;
+
+	if (pdev->dev.of_node) {
+		pdata->sda_pin = sda_pin;
+		pdata->scl_pin = scl_pin;
+		of_i2c_gpio_get_props(pdev->dev.of_node, pdata);
+	} else {
+		memcpy(pdata, pdev->dev.platform_data, sizeof(*pdata));
+	}
 
 	if (pdata->sda_is_open_drain) {
 		gpio_direction_output(pdata->sda_pin, 1);
@@ -211,9 +236,9 @@ static int i2c_gpio_probe(struct platform_device *pdev)
 	return 0;
 
 err_add_bus:
-	gpio_free(pdata->scl_pin);
+	gpio_free(scl_pin);
 err_request_scl:
-	gpio_free(pdata->sda_pin);
+	gpio_free(sda_pin);
 err_request_sda:
 	return ret;
 }

drivers/i2c/busses/i2c-intel-mid.c

@@ -1082,8 +1082,7 @@ static void intel_mid_i2c_remove(struct pci_dev *dev)
 {
 	struct intel_mid_i2c_private *mrst = pci_get_drvdata(dev);
 	intel_mid_i2c_disable(&mrst->adap);
-	if (i2c_del_adapter(&mrst->adap))
-		dev_err(&dev->dev, "Failed to delete i2c adapter");
+	i2c_del_adapter(&mrst->adap);
 
 	free_irq(dev->irq, mrst);
 	iounmap(mrst->base);

drivers/i2c/busses/i2c-ismt.c

@@ -183,7 +183,7 @@ struct ismt_priv {
 /**
  * ismt_ids - PCI device IDs supported by this driver
  */
-static const DEFINE_PCI_DEVICE_TABLE(ismt_ids) = {
+static DEFINE_PCI_DEVICE_TABLE(ismt_ids) = {
 	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_S1200_SMT0) },
 	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_S1200_SMT1) },
 	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_AVOTON_SMT) },

drivers/i2c/busses/i2c-mv64xxx.c

@@ -701,9 +701,8 @@ static int
 mv64xxx_i2c_remove(struct platform_device *dev)
 {
 	struct mv64xxx_i2c_data		*drv_data = platform_get_drvdata(dev);
-	int	rc;
 
-	rc = i2c_del_adapter(&drv_data->adapter);
+	i2c_del_adapter(&drv_data->adapter);
 	free_irq(drv_data->irq, drv_data);
 	mv64xxx_i2c_unmap_regs(drv_data);
 #if defined(CONFIG_HAVE_CLK)
@@ -715,7 +714,7 @@ mv64xxx_i2c_remove(struct platform_device *dev)
 #endif
 	kfree(drv_data);
 
-	return rc;
+	return 0;
 }
 
 static const struct of_device_id mv64xxx_i2c_of_match_table[] = {

drivers/i2c/busses/i2c-mxs.c

@@ -56,6 +56,7 @@
 #define MXS_I2C_CTRL1_SET	(0x44)
 #define MXS_I2C_CTRL1_CLR	(0x48)
 
+#define MXS_I2C_CTRL1_CLR_GOT_A_NAK		0x10000000
 #define MXS_I2C_CTRL1_BUS_FREE_IRQ		0x80
 #define MXS_I2C_CTRL1_DATA_ENGINE_CMPLT_IRQ	0x40
 #define MXS_I2C_CTRL1_NO_SLAVE_ACK_IRQ		0x20
@@ -65,6 +66,10 @@
 #define MXS_I2C_CTRL1_SLAVE_STOP_IRQ		0x02
 #define MXS_I2C_CTRL1_SLAVE_IRQ			0x01
 
+#define MXS_I2C_STAT		(0x50)
+#define MXS_I2C_STAT_BUS_BUSY			0x00000800
+#define MXS_I2C_STAT_CLK_GEN_BUSY		0x00000400
+
 #define MXS_I2C_DATA		(0xa0)
 
 #define MXS_I2C_DEBUG0		(0xb0)
@@ -297,12 +302,10 @@ static int mxs_i2c_pio_wait_dmareq(struct mxs_i2c_dev *i2c)
 		cond_resched();
 	}
 
-	writel(MXS_I2C_DEBUG0_DMAREQ, i2c->regs + MXS_I2C_DEBUG0_CLR);
-
 	return 0;
 }
 
-static int mxs_i2c_pio_wait_cplt(struct mxs_i2c_dev *i2c)
+static int mxs_i2c_pio_wait_cplt(struct mxs_i2c_dev *i2c, int last)
 {
 	unsigned long timeout = jiffies + msecs_to_jiffies(1000);
 
@@ -323,9 +326,50 @@ static int mxs_i2c_pio_wait_cplt(struct mxs_i2c_dev *i2c)
 	writel(MXS_I2C_CTRL1_DATA_ENGINE_CMPLT_IRQ,
 		i2c->regs + MXS_I2C_CTRL1_CLR);
 
+	/*
+	 * When ending a transfer with a stop, we have to wait for the bus to
+	 * go idle before we report the transfer as completed. Otherwise the
+	 * start of the next transfer may race with the end of the current one.
+	 */
+	while (last && (readl(i2c->regs + MXS_I2C_STAT) &
+			(MXS_I2C_STAT_BUS_BUSY | MXS_I2C_STAT_CLK_GEN_BUSY))) {
+		if (time_after(jiffies, timeout))
+			return -ETIMEDOUT;
+		cond_resched();
+	}
+
 	return 0;
 }
 
+static int mxs_i2c_pio_check_error_state(struct mxs_i2c_dev *i2c)
+{
+	u32 state;
+
+	state = readl(i2c->regs + MXS_I2C_CTRL1_CLR) & MXS_I2C_IRQ_MASK;
+
+	if (state & MXS_I2C_CTRL1_NO_SLAVE_ACK_IRQ)
+		i2c->cmd_err = -ENXIO;
+	else if (state & (MXS_I2C_CTRL1_EARLY_TERM_IRQ |
+			  MXS_I2C_CTRL1_MASTER_LOSS_IRQ |
+			  MXS_I2C_CTRL1_SLAVE_STOP_IRQ |
+			  MXS_I2C_CTRL1_SLAVE_IRQ))
+		i2c->cmd_err = -EIO;
+
+	return i2c->cmd_err;
+}
+
+static void mxs_i2c_pio_trigger_cmd(struct mxs_i2c_dev *i2c, u32 cmd)
+{
+	u32 reg;
+
+	writel(cmd, i2c->regs + MXS_I2C_CTRL0);
+
+	/* readback makes sure the write is latched into hardware */
+	reg = readl(i2c->regs + MXS_I2C_CTRL0);
+	reg |= MXS_I2C_CTRL0_RUN;
+	writel(reg, i2c->regs + MXS_I2C_CTRL0);
+}
+
 static int mxs_i2c_pio_setup_xfer(struct i2c_adapter *adap,
 			struct i2c_msg *msg, uint32_t flags)
 {
@@ -341,23 +385,26 @@ static int mxs_i2c_pio_setup_xfer(struct i2c_adapter *adap,
 		addr_data |= I2C_SMBUS_READ;
 
 		/* SELECT command. */
-		writel(MXS_I2C_CTRL0_RUN | MXS_CMD_I2C_SELECT,
-			i2c->regs + MXS_I2C_CTRL0);
+		mxs_i2c_pio_trigger_cmd(i2c, MXS_CMD_I2C_SELECT);
 
 		ret = mxs_i2c_pio_wait_dmareq(i2c);
 		if (ret)
 			return ret;
 
 		writel(addr_data, i2c->regs + MXS_I2C_DATA);
+		writel(MXS_I2C_DEBUG0_DMAREQ, i2c->regs + MXS_I2C_DEBUG0_CLR);
 
-		ret = mxs_i2c_pio_wait_cplt(i2c);
+		ret = mxs_i2c_pio_wait_cplt(i2c, 0);
 		if (ret)
 			return ret;
 
+		if (mxs_i2c_pio_check_error_state(i2c))
+			goto cleanup;
+
 		/* READ command. */
-		writel(MXS_I2C_CTRL0_RUN | MXS_CMD_I2C_READ | flags |
-			MXS_I2C_CTRL0_XFER_COUNT(msg->len),
-			i2c->regs + MXS_I2C_CTRL0);
+		mxs_i2c_pio_trigger_cmd(i2c,
+					MXS_CMD_I2C_READ | flags |
+					MXS_I2C_CTRL0_XFER_COUNT(msg->len));
 
 		for (i = 0; i < msg->len; i++) {
 			if ((i & 3) == 0) {
@@ -365,6 +412,8 @@ static int mxs_i2c_pio_setup_xfer(struct i2c_adapter *adap,
 				if (ret)
 					return ret;
 				data = readl(i2c->regs + MXS_I2C_DATA);
+				writel(MXS_I2C_DEBUG0_DMAREQ,
+				       i2c->regs + MXS_I2C_DEBUG0_CLR);
 			}
 			msg->buf[i] = data & 0xff;
 			data >>= 8;
@@ -373,9 +422,9 @@ static int mxs_i2c_pio_setup_xfer(struct i2c_adapter *adap,
 		addr_data |= I2C_SMBUS_WRITE;
 
 		/* WRITE command. */
-		writel(MXS_I2C_CTRL0_RUN | MXS_CMD_I2C_WRITE | flags |
-			MXS_I2C_CTRL0_XFER_COUNT(msg->len + 1),
-			i2c->regs + MXS_I2C_CTRL0);
+		mxs_i2c_pio_trigger_cmd(i2c,
+					MXS_CMD_I2C_WRITE | flags |
+					MXS_I2C_CTRL0_XFER_COUNT(msg->len + 1));
 
 		/*
 		 * The LSB of data buffer is the first byte blasted across
@@ -391,6 +440,8 @@ static int mxs_i2c_pio_setup_xfer(struct i2c_adapter *adap,
 				if (ret)
 					return ret;
 				writel(data, i2c->regs + MXS_I2C_DATA);
+				writel(MXS_I2C_DEBUG0_DMAREQ,
+				       i2c->regs + MXS_I2C_DEBUG0_CLR);
 			}
 		}
 
@@ -401,13 +452,19 @@ static int mxs_i2c_pio_setup_xfer(struct i2c_adapter *adap,
 			if (ret)
 				return ret;
 			writel(data, i2c->regs + MXS_I2C_DATA);
+			writel(MXS_I2C_DEBUG0_DMAREQ,
+			       i2c->regs + MXS_I2C_DEBUG0_CLR);
 		}
 	}
 
-	ret = mxs_i2c_pio_wait_cplt(i2c);
+	ret = mxs_i2c_pio_wait_cplt(i2c, flags & MXS_I2C_CTRL0_POST_SEND_STOP);
 	if (ret)
 		return ret;
 
+	/* make sure we capture any occurred error into cmd_err */
+	mxs_i2c_pio_check_error_state(i2c);
+
+cleanup:
 	/* Clear any dangling IRQs and re-enable interrupts. */
 	writel(MXS_I2C_IRQ_MASK, i2c->regs + MXS_I2C_CTRL1_CLR);
 	writel(MXS_I2C_IRQ_MASK << 8, i2c->regs + MXS_I2C_CTRL1_SET);
@@ -439,12 +496,12 @@ static int mxs_i2c_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg,
 	 * using PIO mode while longer transfers use DMA. The 8 byte border is
 	 * based on this empirical measurement and a lot of previous frobbing.
 	 */
+	i2c->cmd_err = 0;
 	if (msg->len < 8) {
 		ret = mxs_i2c_pio_setup_xfer(adap, msg, flags);
 		if (ret)
 			mxs_i2c_reset(i2c);
 	} else {
-		i2c->cmd_err = 0;
 		INIT_COMPLETION(i2c->cmd_complete);
 		ret = mxs_i2c_dma_setup_xfer(adap, msg, flags);
 		if (ret)
@@ -454,13 +511,19 @@ static int mxs_i2c_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg,
 						msecs_to_jiffies(1000));
 		if (ret == 0)
 			goto timeout;
+	}
 
-		if (i2c->cmd_err == -ENXIO)
-			mxs_i2c_reset(i2c);
-
-		ret = i2c->cmd_err;
+	if (i2c->cmd_err == -ENXIO) {
+		/*
+		 * If the transfer fails with a NAK from the slave the
+		 * controller halts until it gets told to return to idle state.
+		 */
+		writel(MXS_I2C_CTRL1_CLR_GOT_A_NAK,
+		       i2c->regs + MXS_I2C_CTRL1_SET);
 	}
 
+	ret = i2c->cmd_err;
+
 	dev_dbg(i2c->dev, "Done with err=%d\n", ret);
 
 	return ret;
@@ -686,11 +749,8 @@ static int mxs_i2c_probe(struct platform_device *pdev)
 static int mxs_i2c_remove(struct platform_device *pdev)
 {
 	struct mxs_i2c_dev *i2c = platform_get_drvdata(pdev);
-	int ret;
 
-	ret = i2c_del_adapter(&i2c->adapter);
-	if (ret)
-		return -EBUSY;
+	i2c_del_adapter(&i2c->adapter);
 
 	if (i2c->dmach)
 		dma_release_channel(i2c->dmach);

drivers/i2c/busses/i2c-nforce2-s4985.c

@@ -164,11 +164,7 @@ static int __init nforce2_s4985_init(void)
 	}
 
 	/* Unregister physical bus */
-	error = i2c_del_adapter(nforce2_smbus);
-	if (error) {
-		dev_err(&nforce2_smbus->dev, "Physical bus removal failed\n");
-		goto ERROR0;
-	}
+	i2c_del_adapter(nforce2_smbus);
 
 	printk(KERN_INFO "Enabling SMBus multiplexing for Tyan S4985\n");
 	/* Define the 5 virtual adapters and algorithms structures */

drivers/i2c/busses/i2c-octeon.c

@@ -183,7 +183,7 @@ static irqreturn_t octeon_i2c_isr(int irq, void *dev_id)
 	struct octeon_i2c *i2c = dev_id;
 
 	octeon_i2c_int_disable(i2c);
-	wake_up_interruptible(&i2c->queue);
+	wake_up(&i2c->queue);
 
 	return IRQ_HANDLED;
 }
@@ -206,9 +206,9 @@ static int octeon_i2c_wait(struct octeon_i2c *i2c)
 
 	octeon_i2c_int_enable(i2c);
 
-	result = wait_event_interruptible_timeout(i2c->queue,
-						  octeon_i2c_test_iflg(i2c),
-						  i2c->adap.timeout);
+	result = wait_event_timeout(i2c->queue,
+					octeon_i2c_test_iflg(i2c),
+					i2c->adap.timeout);
 
 	octeon_i2c_int_disable(i2c);
 
@@ -440,7 +440,7 @@ static struct i2c_adapter octeon_i2c_ops = {
 	.owner = THIS_MODULE,
 	.name = "OCTEON adapter",
 	.algo = &octeon_i2c_algo,
-	.timeout = 2,
+	.timeout = HZ / 50,
 };
 
 /**

drivers/i2c/busses/i2c-powermac.c

@@ -213,14 +213,8 @@ static const struct i2c_algorithm i2c_powermac_algorithm = {
 static int i2c_powermac_remove(struct platform_device *dev)
 {
 	struct i2c_adapter	*adapter = platform_get_drvdata(dev);
-	int			rc;
-
-	rc = i2c_del_adapter(adapter);
-	/* We aren't that prepared to deal with this... */
-	if (rc)
-		printk(KERN_WARNING
-		       "i2c-powermac.c: Failed to remove bus %s !\n",
-		       adapter->name);
+
+	i2c_del_adapter(adapter);
 	memset(adapter, 0, sizeof(*adapter));
 
 	return 0;

drivers/i2c/busses/i2c-puv3.c

@@ -234,21 +234,15 @@ static int puv3_i2c_remove(struct platform_device *pdev)
 {
 	struct i2c_adapter *adapter = platform_get_drvdata(pdev);
 	struct resource *mem;
-	int rc;
 
-	rc = i2c_del_adapter(adapter);
-	if (rc) {
-		dev_err(&pdev->dev, "Adapter '%s' delete fail\n",
-				adapter->name);
-		return rc;
-	}
+	i2c_del_adapter(adapter);
 
 	put_device(&pdev->dev);
 
 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	release_mem_region(mem->start, resource_size(mem));
 
-	return rc;
+	return 0;
 }
 
 #ifdef CONFIG_PM

drivers/i2c/busses/i2c-pxa.c

@@ -1053,16 +1053,13 @@ static int i2c_pxa_probe_dt(struct platform_device *pdev, struct pxa_i2c *i2c,
 	struct device_node *np = pdev->dev.of_node;
 	const struct of_device_id *of_id =
 			of_match_device(i2c_pxa_dt_ids, &pdev->dev);
-	int ret;
 
 	if (!of_id)
 		return 1;
-	ret = of_alias_get_id(np, "i2c");
-	if (ret < 0) {
-		dev_err(&pdev->dev, "failed to get alias id, errno %d\n", ret);
-		return ret;
-	}
-	pdev->id = ret;
+
+	/* For device tree we always use the dynamic or alias-assigned ID */
+	i2c->adap.nr = -1;
+
 	if (of_get_property(np, "mrvl,i2c-polling", NULL))
 		i2c->use_pio = 1;
 	if (of_get_property(np, "mrvl,i2c-fast-mode", NULL))
@@ -1100,6 +1097,9 @@ static int i2c_pxa_probe(struct platform_device *dev)
 		goto emalloc;
 	}
 
+	/* Default adapter num to device id; i2c_pxa_probe_dt can override. */
+	i2c->adap.nr = dev->id;
+
 	ret = i2c_pxa_probe_dt(dev, i2c, &i2c_type);
 	if (ret > 0)
 		ret = i2c_pxa_probe_pdata(dev, i2c, &i2c_type);
@@ -1124,9 +1124,7 @@ static int i2c_pxa_probe(struct platform_device *dev)
 	spin_lock_init(&i2c->lock);
 	init_waitqueue_head(&i2c->wait);
 
-	i2c->adap.nr = dev->id;
-	snprintf(i2c->adap.name, sizeof(i2c->adap.name), "pxa_i2c-i2c.%u",
-		 i2c->adap.nr);
+	strlcpy(i2c->adap.name, "pxa_i2c-i2c", sizeof(i2c->adap.name));
 
 	i2c->clk = clk_get(&dev->dev, NULL);
 	if (IS_ERR(i2c->clk)) {
@@ -1169,7 +1167,7 @@ static int i2c_pxa_probe(struct platform_device *dev)
 	} else {
 		i2c->adap.algo = &i2c_pxa_algorithm;
 		ret = request_irq(irq, i2c_pxa_handler, IRQF_SHARED,
-				  i2c->adap.name, i2c);
+				  dev_name(&dev->dev), i2c);
 		if (ret)
 			goto ereqirq;
 	}

drivers/i2c/busses/i2c-s3c2410.c

@@ -42,9 +42,46 @@
 
 #include <asm/irq.h>
 
-#include <plat/regs-iic.h>
 #include <linux/platform_data/i2c-s3c2410.h>
 
+/* see s3c2410x user guide, v1.1, section 9 (p447) for more info */
+
+#define S3C2410_IICCON			0x00
+#define S3C2410_IICSTAT			0x04
+#define S3C2410_IICADD			0x08
+#define S3C2410_IICDS			0x0C
+#define S3C2440_IICLC			0x10
+
+#define S3C2410_IICCON_ACKEN		(1 << 7)
+#define S3C2410_IICCON_TXDIV_16		(0 << 6)
+#define S3C2410_IICCON_TXDIV_512	(1 << 6)
+#define S3C2410_IICCON_IRQEN		(1 << 5)
+#define S3C2410_IICCON_IRQPEND		(1 << 4)
+#define S3C2410_IICCON_SCALE(x)		((x) & 0xf)
+#define S3C2410_IICCON_SCALEMASK	(0xf)
+
+#define S3C2410_IICSTAT_MASTER_RX	(2 << 6)
+#define S3C2410_IICSTAT_MASTER_TX	(3 << 6)
+#define S3C2410_IICSTAT_SLAVE_RX	(0 << 6)
+#define S3C2410_IICSTAT_SLAVE_TX	(1 << 6)
+#define S3C2410_IICSTAT_MODEMASK	(3 << 6)
+
+#define S3C2410_IICSTAT_START		(1 << 5)
+#define S3C2410_IICSTAT_BUSBUSY		(1 << 5)
+#define S3C2410_IICSTAT_TXRXEN		(1 << 4)
+#define S3C2410_IICSTAT_ARBITR		(1 << 3)
+#define S3C2410_IICSTAT_ASSLAVE		(1 << 2)
+#define S3C2410_IICSTAT_ADDR0		(1 << 1)
+#define S3C2410_IICSTAT_LASTBIT		(1 << 0)
+
+#define S3C2410_IICLC_SDA_DELAY0	(0 << 0)
+#define S3C2410_IICLC_SDA_DELAY5	(1 << 0)
+#define S3C2410_IICLC_SDA_DELAY10	(2 << 0)
+#define S3C2410_IICLC_SDA_DELAY15	(3 << 0)
+#define S3C2410_IICLC_SDA_DELAY_MASK	(3 << 0)
+
+#define S3C2410_IICLC_FILTER_ON		(1 << 2)
+
 /* Treat S3C2410 as baseline hardware, anything else is supported via quirks */
 #define QUIRK_S3C2440		(1 << 0)
 #define QUIRK_HDMIPHY		(1 << 1)
@@ -309,6 +346,12 @@ static inline int is_lastmsg(struct s3c24xx_i2c *i2c)
 
 static inline int is_msglast(struct s3c24xx_i2c *i2c)
 {
+	/* msg->len is always 1 for the first byte of smbus block read.
+	 * Actual length will be read from slave. More bytes will be
+	 * read according to the length then. */
+	if (i2c->msg->flags & I2C_M_RECV_LEN && i2c->msg->len == 1)
+		return 0;
+
 	return i2c->msg_ptr == i2c->msg->len-1;
 }
 
@@ -448,6 +491,9 @@ static int i2c_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat)
 		byte = readb(i2c->regs + S3C2410_IICDS);
 		i2c->msg->buf[i2c->msg_ptr++] = byte;
 
+		/* Add actual length to read for smbus block read */
+		if (i2c->msg->flags & I2C_M_RECV_LEN && i2c->msg->len == 1)
+			i2c->msg->len += byte;
  prepare_read:
 		if (is_msglast(i2c)) {
 			/* last byte of buffer */

drivers/i2c/busses/i2c-tegra.c

@@ -25,7 +25,6 @@
 #include <linux/interrupt.h>
 #include <linux/delay.h>
 #include <linux/slab.h>
-#include <linux/i2c-tegra.h>
 #include <linux/of_i2c.h>
 #include <linux/of_device.h>
 #include <linux/module.h>
@@ -172,7 +171,7 @@ struct tegra_i2c_dev {
 	u8 *msg_buf;
 	size_t msg_buf_remaining;
 	int msg_read;
-	unsigned long bus_clk_rate;
+	u32 bus_clk_rate;
 	bool is_suspended;
 };
 
@@ -694,7 +693,6 @@ static const struct tegra_i2c_hw_feature tegra114_i2c_hw = {
 	.clk_divisor_std_fast_mode = 0x19,
 };
 
-#if defined(CONFIG_OF)
 /* Match table for of_platform binding */
 static const struct of_device_id tegra_i2c_of_match[] = {
 	{ .compatible = "nvidia,tegra114-i2c", .data = &tegra114_i2c_hw, },
@@ -704,16 +702,13 @@ static const struct of_device_id tegra_i2c_of_match[] = {
 	{},
 };
 MODULE_DEVICE_TABLE(of, tegra_i2c_of_match);
-#endif
 
 static int tegra_i2c_probe(struct platform_device *pdev)
 {
 	struct tegra_i2c_dev *i2c_dev;
-	struct tegra_i2c_platform_data *pdata = pdev->dev.platform_data;
 	struct resource *res;
 	struct clk *div_clk;
 	struct clk *fast_clk;
-	const unsigned int *prop;
 	void __iomem *base;
 	int irq;
 	int ret = 0;
@@ -754,23 +749,16 @@ static int tegra_i2c_probe(struct platform_device *pdev)
 	i2c_dev->cont_id = pdev->id;
 	i2c_dev->dev = &pdev->dev;
 
-	i2c_dev->bus_clk_rate = 100000; /* default clock rate */
-	if (pdata) {
-		i2c_dev->bus_clk_rate = pdata->bus_clk_rate;
-
-	} else if (i2c_dev->dev->of_node) {    /* if there is a device tree node ... */
-		prop = of_get_property(i2c_dev->dev->of_node,
-				"clock-frequency", NULL);
-		if (prop)
-			i2c_dev->bus_clk_rate = be32_to_cpup(prop);
-	}
+	ret = of_property_read_u32(i2c_dev->dev->of_node, "clock-frequency",
+					&i2c_dev->bus_clk_rate);
+	if (ret)
+		i2c_dev->bus_clk_rate = 100000; /* default clock rate */
 
 	i2c_dev->hw = &tegra20_i2c_hw;
 
 	if (pdev->dev.of_node) {
 		const struct of_device_id *match;
-		match = of_match_device(of_match_ptr(tegra_i2c_of_match),
-						&pdev->dev);
+		match = of_match_device(tegra_i2c_of_match, &pdev->dev);
 		i2c_dev->hw = match->data;
 		i2c_dev->is_dvc = of_device_is_compatible(pdev->dev.of_node,
 						"nvidia,tegra20-i2c-dvc");
@@ -876,7 +864,7 @@ static struct platform_driver tegra_i2c_driver = {
 	.driver  = {
 		.name  = "tegra-i2c",
 		.owner = THIS_MODULE,
-		.of_match_table = of_match_ptr(tegra_i2c_of_match),
+		.of_match_table = tegra_i2c_of_match,
 		.pm    = TEGRA_I2C_PM,
 	},
 };

drivers/i2c/busses/i2c-viperboard.c

@@ -421,11 +421,10 @@ static int vprbrd_i2c_probe(struct platform_device *pdev)
 static int vprbrd_i2c_remove(struct platform_device *pdev)
 {
 	struct vprbrd_i2c *vb_i2c = platform_get_drvdata(pdev);
-	int ret;
 
-	ret = i2c_del_adapter(&vb_i2c->i2c);
+	i2c_del_adapter(&vb_i2c->i2c);
 
-	return ret;
+	return 0;
 }
 
 static struct platform_driver vprbrd_i2c_driver = {

drivers/i2c/busses/i2c-xiic.c

@@ -312,10 +312,8 @@ static void xiic_fill_tx_fifo(struct xiic_i2c *i2c)
 			/* last message in transfer -> STOP */
 			data |= XIIC_TX_DYN_STOP_MASK;
 			dev_dbg(i2c->adap.dev.parent, "%s TX STOP\n", __func__);
-
-			xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, data);
-		} else
-			xiic_setreg8(i2c, XIIC_DTR_REG_OFFSET, data);
+		}
+		xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, data);
 	}
 }
 

drivers/i2c/i2c-mux.c

@@ -191,17 +191,12 @@ struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent,
 }
 EXPORT_SYMBOL_GPL(i2c_add_mux_adapter);
 
-int i2c_del_mux_adapter(struct i2c_adapter *adap)
+void i2c_del_mux_adapter(struct i2c_adapter *adap)
 {
 	struct i2c_mux_priv *priv = adap->algo_data;
-	int ret;
 
-	ret = i2c_del_adapter(adap);
-	if (ret < 0)
-		return ret;
+	i2c_del_adapter(adap);
 	kfree(priv);
-
-	return 0;
 }
 EXPORT_SYMBOL_GPL(i2c_del_mux_adapter);
 

drivers/i2c/muxes/Kconfig

@@ -5,6 +5,18 @@
 menu "Multiplexer I2C Chip support"
 	depends on I2C_MUX
 
+config I2C_ARB_GPIO_CHALLENGE
+	tristate "GPIO-based I2C arbitration"
+	depends on GENERIC_GPIO && OF
+	help
+	  If you say yes to this option, support will be included for an
+	  I2C multimaster arbitration scheme using GPIOs and a challenge &
+	  response mechanism where masters have to claim the bus by asserting
+	  a GPIO.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called i2c-arb-gpio-challenge.
+
 config I2C_MUX_GPIO
 	tristate "GPIO-based I2C multiplexer"
 	depends on GENERIC_GPIO

drivers/i2c/muxes/Makefile

 #
 # Makefile for multiplexer I2C chip drivers.
 
+obj-$(CONFIG_I2C_ARB_GPIO_CHALLENGE)	+= i2c-arb-gpio-challenge.o
+
 obj-$(CONFIG_I2C_MUX_GPIO)	+= i2c-mux-gpio.o
 obj-$(CONFIG_I2C_MUX_PCA9541)	+= i2c-mux-pca9541.o
 obj-$(CONFIG_I2C_MUX_PCA954x)	+= i2c-mux-pca954x.o

drivers/i2c/muxes/i2c-arb-gpio-challenge.c

+/*
+ * GPIO-based I2C Arbitration Using a Challenge & Response Mechanism
+ *
+ * Copyright (C) 2012 Google, Inc
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/delay.h>
+#include <linux/gpio.h>
+#include <linux/kernel.h>
+#include <linux/i2c.h>
+#include <linux/i2c-mux.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/of_i2c.h>
+#include <linux/of_gpio.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+
+/**
+ * struct i2c_arbitrator_data - Driver data for I2C arbitrator
+ *
+ * @parent: Parent adapter
+ * @child: Child bus
+ * @our_gpio: GPIO we'll use to claim.
+ * @our_gpio_release: 0 if active high; 1 if active low; AKA if the GPIO ==
+ *   this then consider it released.
+ * @their_gpio: GPIO that the other side will use to claim.
+ * @their_gpio_release: 0 if active high; 1 if active low; AKA if the GPIO ==
+ *   this then consider it released.
+ * @slew_delay_us: microseconds to wait for a GPIO to go high.
+ * @wait_retry_us: we'll attempt another claim after this many microseconds.
+ * @wait_free_us: we'll give up after this many microseconds.
+ */
+
+struct i2c_arbitrator_data {
+	struct i2c_adapter *parent;
+	struct i2c_adapter *child;
+	int our_gpio;
+	int our_gpio_release;
+	int their_gpio;
+	int their_gpio_release;
+	unsigned int slew_delay_us;
+	unsigned int wait_retry_us;
+	unsigned int wait_free_us;
+};
+
+
+/**
+ * i2c_arbitrator_select - claim the I2C bus
+ *
+ * Use the GPIO-based signalling protocol; return -EBUSY if we fail.
+ */
+static int i2c_arbitrator_select(struct i2c_adapter *adap, void *data, u32 chan)
+{
+	const struct i2c_arbitrator_data *arb = data;
+	unsigned long stop_retry, stop_time;
+
+	/* Start a round of trying to claim the bus */
+	stop_time = jiffies + usecs_to_jiffies(arb->wait_free_us) + 1;
+	do {
+		/* Indicate that we want to claim the bus */
+		gpio_set_value(arb->our_gpio, !arb->our_gpio_release);
+		udelay(arb->slew_delay_us);
+
+		/* Wait for the other master to release it */
+		stop_retry = jiffies + usecs_to_jiffies(arb->wait_retry_us) + 1;
+		while (time_before(jiffies, stop_retry)) {
+			int gpio_val = !!gpio_get_value(arb->their_gpio);
+
+			if (gpio_val == arb->their_gpio_release) {
+				/* We got it, so return */
+				return 0;
+			}
+
+			usleep_range(50, 200);
+		}
+
+		/* It didn't release, so give up, wait, and try again */
+		gpio_set_value(arb->our_gpio, arb->our_gpio_release);
+
+		usleep_range(arb->wait_retry_us, arb->wait_retry_us * 2);
+	} while (time_before(jiffies, stop_time));
+
+	/* Give up, release our claim */
+	gpio_set_value(arb->our_gpio, arb->our_gpio_release);
+	udelay(arb->slew_delay_us);
+	dev_err(&adap->dev, "Could not claim bus, timeout\n");
+	return -EBUSY;
+}
+
+/**
+ * i2c_arbitrator_deselect - release the I2C bus
+ *
+ * Release the I2C bus using the GPIO-based signalling protocol.
+ */
+static int i2c_arbitrator_deselect(struct i2c_adapter *adap, void *data,
+				   u32 chan)
+{
+	const struct i2c_arbitrator_data *arb = data;
+
+	/* Release the bus and wait for the other master to notice */
+	gpio_set_value(arb->our_gpio, arb->our_gpio_release);
+	udelay(arb->slew_delay_us);
+
+	return 0;
+}
+
+static int i2c_arbitrator_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct device_node *parent_np;
+	struct i2c_arbitrator_data *arb;
+	enum of_gpio_flags gpio_flags;
+	unsigned long out_init;
+	int ret;
+
+	/* We only support probing from device tree; no platform_data */
+	if (!np) {
+		dev_err(dev, "Cannot find device tree node\n");
+		return -ENODEV;
+	}
+	if (dev->platform_data) {
+		dev_err(dev, "Platform data is not supported\n");
+		return -EINVAL;
+	}
+
+	arb = devm_kzalloc(dev, sizeof(*arb), GFP_KERNEL);
+	if (!arb) {
+		dev_err(dev, "Cannot allocate i2c_arbitrator_data\n");
+		return -ENOMEM;
+	}
+	platform_set_drvdata(pdev, arb);
+
+	/* Request GPIOs */
+	ret = of_get_named_gpio_flags(np, "our-claim-gpio", 0, &gpio_flags);
+	if (!gpio_is_valid(ret)) {
+		if (ret != -EPROBE_DEFER)
+			dev_err(dev, "Error getting our-claim-gpio\n");
+		return ret;
+	}
+	arb->our_gpio = ret;
+	arb->our_gpio_release = !!(gpio_flags & OF_GPIO_ACTIVE_LOW);
+	out_init = (gpio_flags & OF_GPIO_ACTIVE_LOW) ?
+		GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
+	ret = devm_gpio_request_one(dev, arb->our_gpio, out_init,
+				    "our-claim-gpio");
+	if (ret) {
+		if (ret != -EPROBE_DEFER)
+			dev_err(dev, "Error requesting our-claim-gpio\n");
+		return ret;
+	}
+
+	ret = of_get_named_gpio_flags(np, "their-claim-gpios", 0, &gpio_flags);
+	if (!gpio_is_valid(ret)) {
+		if (ret != -EPROBE_DEFER)
+			dev_err(dev, "Error getting their-claim-gpio\n");
+		return ret;
+	}
+	arb->their_gpio = ret;
+	arb->their_gpio_release = !!(gpio_flags & OF_GPIO_ACTIVE_LOW);
+	ret = devm_gpio_request_one(dev, arb->their_gpio, GPIOF_IN,
+				    "their-claim-gpio");
+	if (ret) {
+		if (ret != -EPROBE_DEFER)
+			dev_err(dev, "Error requesting their-claim-gpio\n");
+		return ret;
+	}
+
+	/* At the moment we only support a single two master (us + 1 other) */
+	if (gpio_is_valid(of_get_named_gpio(np, "their-claim-gpios", 1))) {
+		dev_err(dev, "Only one other master is supported\n");
+		return -EINVAL;
+	}
+
+	/* Arbitration parameters */
+	if (of_property_read_u32(np, "slew-delay-us", &arb->slew_delay_us))
+		arb->slew_delay_us = 10;
+	if (of_property_read_u32(np, "wait-retry-us", &arb->wait_retry_us))
+		arb->wait_retry_us = 3000;
+	if (of_property_read_u32(np, "wait-free-us", &arb->wait_free_us))
+		arb->wait_free_us = 50000;
+
+	/* Find our parent */
+	parent_np = of_parse_phandle(np, "i2c-parent", 0);
+	if (!parent_np) {
+		dev_err(dev, "Cannot parse i2c-parent\n");
+		return -EINVAL;
+	}
+	arb->parent = of_find_i2c_adapter_by_node(parent_np);
+	if (!arb->parent) {
+		dev_err(dev, "Cannot find parent bus\n");
+		return -EINVAL;
+	}
+
+	/* Actually add the mux adapter */
+	arb->child = i2c_add_mux_adapter(arb->parent, dev, arb, 0, 0, 0,
+					 i2c_arbitrator_select,
+					 i2c_arbitrator_deselect);
+	if (!arb->child) {
+		dev_err(dev, "Failed to add adapter\n");
+		ret = -ENODEV;
+		i2c_put_adapter(arb->parent);
+	}
+
+	return ret;
+}
+
+static int i2c_arbitrator_remove(struct platform_device *pdev)
+{
+	struct i2c_arbitrator_data *arb = platform_get_drvdata(pdev);
+
+	i2c_del_mux_adapter(arb->child);
+	i2c_put_adapter(arb->parent);
+
+	return 0;
+}
+
+static const struct of_device_id i2c_arbitrator_of_match[] = {
+	{ .compatible = "i2c-arb-gpio-challenge", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, i2c_arbitrator_of_match);
+
+static struct platform_driver i2c_arbitrator_driver = {
+	.probe	= i2c_arbitrator_probe,
+	.remove	= i2c_arbitrator_remove,
+	.driver	= {
+		.owner	= THIS_MODULE,
+		.name	= "i2c-arb-gpio-challenge",
+		.of_match_table = of_match_ptr(i2c_arbitrator_of_match),
+	},
+};
+
+module_platform_driver(i2c_arbitrator_driver);
+
+MODULE_DESCRIPTION("GPIO-based I2C Arbitration");
+MODULE_AUTHOR("Doug Anderson <dianders@chromium.org>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:i2c-arb-gpio-challenge");

drivers/i2c/muxes/i2c-mux-gpio.c

@@ -201,10 +201,21 @@ static int i2c_mux_gpio_probe(struct platform_device *pdev)
 
 	for (i = 0; i < mux->data.n_gpios; i++) {
 		ret = gpio_request(gpio_base + mux->data.gpios[i], "i2c-mux-gpio");
-		if (ret)
+		if (ret) {
+			dev_err(&pdev->dev, "Failed to request GPIO %d\n",
+				mux->data.gpios[i]);
 			goto err_request_gpio;
-		gpio_direction_output(gpio_base + mux->data.gpios[i],
-				      initial_state & (1 << i));
+		}
+
+		ret = gpio_direction_output(gpio_base + mux->data.gpios[i],
+					    initial_state & (1 << i));
+		if (ret) {
+			dev_err(&pdev->dev,
+				"Failed to set direction of GPIO %d to output\n",
+				mux->data.gpios[i]);
+			i++;	/* gpio_request above succeeded, so must free */
+			goto err_request_gpio;
+		}
 	}
 
 	for (i = 0; i < mux->data.n_values; i++) {

drivers/i2c/muxes/i2c-mux-pca954x.c

@@ -262,13 +262,11 @@ static int pca954x_remove(struct i2c_client *client)
 {
 	struct pca954x *data = i2c_get_clientdata(client);
 	const struct chip_desc *chip = &chips[data->type];
-	int i, err;
+	int i;
 
 	for (i = 0; i < chip->nchans; ++i)
 		if (data->virt_adaps[i]) {
-			err = i2c_del_mux_adapter(data->virt_adaps[i]);
-			if (err)
-				return err;
+			i2c_del_mux_adapter(data->virt_adaps[i]);
 			data->virt_adaps[i] = NULL;
 		}
 

drivers/media/pci/bt8xx/bttv-i2c.c

@@ -397,8 +397,8 @@ int init_bttv_i2c(struct bttv *btv)
 
 int fini_bttv_i2c(struct bttv *btv)
 {
-	if (0 != btv->i2c_rc)
-		return 0;
+	if (btv->i2c_rc == 0)
+		i2c_del_adapter(&btv->c.i2c_adap);
 
-	return i2c_del_adapter(&btv->c.i2c_adap);
+	return 0;
 }

drivers/media/pci/mantis/mantis_i2c.c

@@ -261,6 +261,8 @@ int mantis_i2c_exit(struct mantis_pci *mantis)
 	mmwrite((intmask & ~MANTIS_INT_I2CDONE), MANTIS_INT_MASK);
 
 	dprintk(MANTIS_DEBUG, 1, "Removing I2C adapter");
-	return i2c_del_adapter(&mantis->adapter);
+	i2c_del_adapter(&mantis->adapter);
+
+	return 0;
 }
 EXPORT_SYMBOL_GPL(mantis_i2c_exit);

drivers/net/ethernet/sfc/falcon.c

@@ -1528,7 +1528,7 @@ static int falcon_probe_nic(struct efx_nic *efx)
 	return 0;
 
  fail6:
-	BUG_ON(i2c_del_adapter(&board->i2c_adap));
+	i2c_del_adapter(&board->i2c_adap);
 	memset(&board->i2c_adap, 0, sizeof(board->i2c_adap));
  fail5:
 	efx_nic_free_buffer(efx, &efx->irq_status);
@@ -1666,13 +1666,11 @@ static void falcon_remove_nic(struct efx_nic *efx)
 {
 	struct falcon_nic_data *nic_data = efx->nic_data;
 	struct falcon_board *board = falcon_board(efx);
-	int rc;
 
 	board->type->fini(efx);
 
 	/* Remove I2C adapter and clear it in preparation for a retry */
-	rc = i2c_del_adapter(&board->i2c_adap);
-	BUG_ON(rc);
+	i2c_del_adapter(&board->i2c_adap);
 	memset(&board->i2c_adap, 0, sizeof(board->i2c_adap));
 
 	efx_nic_free_buffer(efx, &efx->irq_status);

drivers/staging/media/go7007/go7007-driver.c

@@ -242,11 +242,8 @@ static void go7007_remove(struct v4l2_device *v4l2_dev)
 	if (go->hpi_ops->release)
 		go->hpi_ops->release(go);
 	if (go->i2c_adapter_online) {
-		if (i2c_del_adapter(&go->i2c_adapter) == 0)
-			go->i2c_adapter_online = 0;
-		else
-			v4l2_err(&go->v4l2_dev,
-				"error removing I2C adapter!\n");
+		i2c_del_adapter(&go->i2c_adapter);
+		go->i2c_adapter_online = 0;
 	}
 
 	kfree(go->boot_fw);

include/linux/i2c-mux.h

@@ -42,7 +42,7 @@ struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent,
 				int (*deselect) (struct i2c_adapter *,
 						 void *mux_dev, u32 chan_id));
 
-int i2c_del_mux_adapter(struct i2c_adapter *adap);
+void i2c_del_mux_adapter(struct i2c_adapter *adap);
 
 #endif /* __KERNEL__ */
 

include/linux/i2c-tegra.h

-/*
- * drivers/i2c/busses/i2c-tegra.c
- *
- * Copyright (C) 2010 Google, Inc.
- * Author: Colin Cross <ccross@android.com>
- *
- * This software is licensed under the terms of the GNU General Public
- * License version 2, as published by the Free Software Foundation, and
- * may be copied, distributed, and modified under those terms.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- */
-
-#ifndef _LINUX_I2C_TEGRA_H
-#define _LINUX_I2C_TEGRA_H
-
-struct tegra_i2c_platform_data {
-	unsigned long bus_clk_rate;
-};
-
-#endif /* _LINUX_I2C_TEGRA_H */

include/linux/i2c.h

@@ -125,7 +125,6 @@ extern s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client,
  * struct i2c_driver - represent an I2C device driver
  * @class: What kind of i2c device we instantiate (for detect)
  * @attach_adapter: Callback for bus addition (deprecated)
- * @detach_adapter: Callback for bus removal (deprecated)
  * @probe: Callback for device binding
  * @remove: Callback for device unbinding
  * @shutdown: Callback for device shutdown
@@ -162,12 +161,10 @@ extern s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client,
 struct i2c_driver {
 	unsigned int class;
 
-	/* Notifies the driver that a new bus has appeared or is about to be
-	 * removed. You should avoid using this, it will be removed in a
-	 * near future.
+	/* Notifies the driver that a new bus has appeared. You should avoid
+	 * using this, it will be removed in a near future.
 	 */
 	int (*attach_adapter)(struct i2c_adapter *) __deprecated;
-	int (*detach_adapter)(struct i2c_adapter *) __deprecated;
 
 	/* Standard driver model interfaces */
 	int (*probe)(struct i2c_client *, const struct i2c_device_id *);
@@ -370,6 +367,45 @@ struct i2c_algorithm {
 	u32 (*functionality) (struct i2c_adapter *);
 };
 
+/**
+ * struct i2c_bus_recovery_info - I2C bus recovery information
+ * @recover_bus: Recover routine. Either pass driver's recover_bus() routine, or
+ *	i2c_generic_scl_recovery() or i2c_generic_gpio_recovery().
+ * @get_scl: This gets current value of SCL line. Mandatory for generic SCL
+ *      recovery. Used internally for generic GPIO recovery.
+ * @set_scl: This sets/clears SCL line. Mandatory for generic SCL recovery. Used
+ *      internally for generic GPIO recovery.
+ * @get_sda: This gets current value of SDA line. Optional for generic SCL
+ *      recovery. Used internally, if sda_gpio is a valid GPIO, for generic GPIO
+ *      recovery.
+ * @prepare_recovery: This will be called before starting recovery. Platform may
+ *	configure padmux here for SDA/SCL line or something else they want.
+ * @unprepare_recovery: This will be called after completing recovery. Platform
+ *	may configure padmux here for SDA/SCL line or something else they want.
+ * @scl_gpio: gpio number of the SCL line. Only required for GPIO recovery.
+ * @sda_gpio: gpio number of the SDA line. Only required for GPIO recovery.
+ */
+struct i2c_bus_recovery_info {
+	int (*recover_bus)(struct i2c_adapter *);
+
+	int (*get_scl)(struct i2c_adapter *);
+	void (*set_scl)(struct i2c_adapter *, int val);
+	int (*get_sda)(struct i2c_adapter *);
+
+	void (*prepare_recovery)(struct i2c_bus_recovery_info *bri);
+	void (*unprepare_recovery)(struct i2c_bus_recovery_info *bri);
+
+	/* gpio recovery */
+	int scl_gpio;
+	int sda_gpio;
+};
+
+int i2c_recover_bus(struct i2c_adapter *adap);
+
+/* Generic recovery routines */
+int i2c_generic_gpio_recovery(struct i2c_adapter *adap);
+int i2c_generic_scl_recovery(struct i2c_adapter *adap);
+
 /*
  * i2c_adapter is the structure used to identify a physical i2c bus along
  * with the access algorithms necessary to access it.
@@ -393,6 +429,8 @@ struct i2c_adapter {
 
 	struct mutex userspace_clients_lock;
 	struct list_head userspace_clients;
+
+	struct i2c_bus_recovery_info *bus_recovery_info;
 };
 #define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)
 
@@ -450,7 +488,7 @@ void i2c_unlock_adapter(struct i2c_adapter *);
  */
 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
 extern int i2c_add_adapter(struct i2c_adapter *);
-extern int i2c_del_adapter(struct i2c_adapter *);
+extern void i2c_del_adapter(struct i2c_adapter *);
 extern int i2c_add_numbered_adapter(struct i2c_adapter *);
 
 extern int i2c_register_driver(struct module *, struct i2c_driver *);