Merge branch 'stmp_device' of git://git.pengutronix.de/git/wsa/linux into next/stmp-dev

Wolfram Sang <w.sang@pengutronix.de> writes:
  This series makes support for a certain type of devices mach independant. We
  want that because such devices (having a special register layout) have been
  found in mach-mxs and mach-mx6 meanwhile.

Since there is no subsystem maintainer for lib/ and the use case is
currently only for ARM systems, I have agreed to merge these through
the arm-soc tree.

* 'stmp_device' of git://git.pengutronix.de/git/wsa/linux:
  i2c: mxs: use global reset function
  lib: add support for stmp-style devices
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

drivers/i2c/busses/Kconfig

@@ -483,6 +483,7 @@ config I2C_MV64XXX
 config I2C_MXS
 	tristate "Freescale i.MX28 I2C interface"
 	depends on SOC_IMX28
+	select STMP_DEVICE
 	help
 	  Say Y here if you want to use the I2C bus controller on
 	  the Freescale i.MX28 processors.

drivers/i2c/busses/i2c-mxs.c

@@ -26,8 +26,7 @@
 #include <linux/platform_device.h>
 #include <linux/jiffies.h>
 #include <linux/io.h>
-
-#include <mach/common.h>
+#include <linux/stmp_device.h>
 
 #define DRIVER_NAME "mxs-i2c"
 
@@ -111,13 +110,9 @@ struct mxs_i2c_dev {
 	struct i2c_adapter adapter;
 };
 
-/*
- * TODO: check if calls to here are really needed. If not, we could get rid of
- * mxs_reset_block and the mach-dependency. Needs an I2C analyzer, probably.
- */
 static void mxs_i2c_reset(struct mxs_i2c_dev *i2c)
 {
-	mxs_reset_block(i2c->regs);
+	stmp_reset_block(i2c->regs);
 	writel(MXS_I2C_IRQ_MASK << 8, i2c->regs + MXS_I2C_CTRL1_SET);
 	writel(MXS_I2C_QUEUECTRL_PIO_QUEUE_MODE,
 			i2c->regs + MXS_I2C_QUEUECTRL_SET);

include/linux/stmp_device.h

+/*
+ * basic functions for devices following the "stmp" style register layout
+ *
+ * Copyright (C) 2011 Wolfram Sang, Pengutronix e.K.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#ifndef __STMP_DEVICE_H__
+#define __STMP_DEVICE_H__
+
+#define STMP_OFFSET_REG_SET	0x4
+#define STMP_OFFSET_REG_CLR	0x8
+#define STMP_OFFSET_REG_TOG	0xc
+
+extern int stmp_reset_block(void __iomem *);
+#endif /* __STMP_DEVICE_H__ */

lib/Kconfig

@@ -33,6 +33,9 @@ config GENERIC_IO
 	boolean
 	default n
 
+config STMP_DEVICE
+	bool
+
 config CRC_CCITT
 	tristate "CRC-CCITT functions"
 	help

lib/Makefile

@@ -123,6 +123,8 @@ obj-$(CONFIG_SIGNATURE) += digsig.o
 
 obj-$(CONFIG_CLZ_TAB) += clz_tab.o
 
+obj-$(CONFIG_STMP_DEVICE) += stmp_device.o
+
 hostprogs-y	:= gen_crc32table
 clean-files	:= crc32table.h
 

lib/stmp_device.c

+/*
+ * Copyright (C) 1999 ARM Limited
+ * Copyright (C) 2000 Deep Blue Solutions Ltd
+ * Copyright 2006-2007,2010 Freescale Semiconductor, Inc. All Rights Reserved.
+ * Copyright 2008 Juergen Beisert, kernel@pengutronix.de
+ * Copyright 2009 Ilya Yanok, Emcraft Systems Ltd, yanok@emcraft.com
+ * Copyright (C) 2011 Wolfram Sang, Pengutronix e.K.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/io.h>
+#include <linux/errno.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/stmp_device.h>
+
+#define STMP_MODULE_CLKGATE	(1 << 30)
+#define STMP_MODULE_SFTRST	(1 << 31)
+
+/*
+ * Clear the bit and poll it cleared.  This is usually called with
+ * a reset address and mask being either SFTRST(bit 31) or CLKGATE
+ * (bit 30).
+ */
+static int stmp_clear_poll_bit(void __iomem *addr, u32 mask)
+{
+	int timeout = 0x400;
+
+	writel(mask, addr + STMP_OFFSET_REG_CLR);
+	udelay(1);
+	while ((readl(addr) & mask) && --timeout)
+		/* nothing */;
+
+	return !timeout;
+}
+
+int stmp_reset_block(void __iomem *reset_addr)
+{
+	int ret;
+	int timeout = 0x400;
+
+	/* clear and poll SFTRST */
+	ret = stmp_clear_poll_bit(reset_addr, STMP_MODULE_SFTRST);
+	if (unlikely(ret))
+		goto error;
+
+	/* clear CLKGATE */
+	writel(STMP_MODULE_CLKGATE, reset_addr + STMP_OFFSET_REG_CLR);
+
+	/* set SFTRST to reset the block */
+	writel(STMP_MODULE_SFTRST, reset_addr + STMP_OFFSET_REG_SET);
+	udelay(1);
+
+	/* poll CLKGATE becoming set */
+	while ((!(readl(reset_addr) & STMP_MODULE_CLKGATE)) && --timeout)
+		/* nothing */;
+	if (unlikely(!timeout))
+		goto error;
+
+	/* clear and poll SFTRST */
+	ret = stmp_clear_poll_bit(reset_addr, STMP_MODULE_SFTRST);
+	if (unlikely(ret))
+		goto error;
+
+	/* clear and poll CLKGATE */
+	ret = stmp_clear_poll_bit(reset_addr, STMP_MODULE_CLKGATE);
+	if (unlikely(ret))
+		goto error;
+
+	return 0;
+
+error:
+	pr_err("%s(%p): module reset timeout\n", __func__, reset_addr);
+	return -ETIMEDOUT;
+}
+EXPORT_SYMBOL(stmp_reset_block);