[PATCH] mips: AMD Alchemy I2C driver

Add I2C drivers for the AMD Alchemy SOCs.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/i2c/busses/Kconfig

@@ -74,6 +74,16 @@ config I2C_AMD8111
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-amd8111.
 
+config I2C_AU1550
+	tristate "Au1550 SMBus interface"
+	depends on I2C && SOC_AU1550
+	help
+	  If you say yes to this option, support will be included for the
+	  Au1550 SMBus interface.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called i2c-au1550.
+
 config I2C_ELEKTOR
 	tristate "Elektor ISA card"
 	depends on I2C && ISA && BROKEN_ON_SMP

drivers/i2c/busses/Makefile

@@ -8,6 +8,7 @@ obj-$(CONFIG_I2C_ALI15X3)	+= i2c-ali15x3.o
 obj-$(CONFIG_I2C_AMD756)	+= i2c-amd756.o
 obj-$(CONFIG_I2C_AMD756_S4882)	+= i2c-amd756-s4882.o
 obj-$(CONFIG_I2C_AMD8111)	+= i2c-amd8111.o
+obj-$(CONFIG_I2C_AU1550)	+= i2c-au1550.o
 obj-$(CONFIG_I2C_ELEKTOR)	+= i2c-elektor.o
 obj-$(CONFIG_I2C_HYDRA)		+= i2c-hydra.o
 obj-$(CONFIG_I2C_I801)		+= i2c-i801.o

drivers/i2c/busses/i2c-au1550.c

+/*
+ * i2c-au1550.c: SMBus (i2c) adapter for Alchemy PSC interface
+ * Copyright (C) 2004 Embedded Edge, LLC <dan@embeddededge.com>
+ *
+ * 2.6 port by Matt Porter <mporter@kernel.crashing.org>
+ *
+ * The documentation describes this as an SMBus controller, but it doesn't
+ * understand any of the SMBus protocol in hardware.  It's really an I2C
+ * controller that could emulate most of the SMBus in software.
+ *
+ * This is just a skeleton adapter to use with the Au1550 PSC
+ * algorithm.  It was developed for the Pb1550, but will work with
+ * any Au1550 board that has a similar PSC configuration.
+ *
+ * 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.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ */
+
+#include <linux/config.h>
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/i2c.h>
+
+#include <asm/mach-au1x00/au1000.h>
+#include <asm/mach-pb1x00/pb1550.h>
+#include <asm/mach-au1x00/au1xxx_psc.h>
+
+#include "i2c-au1550.h"
+
+static int
+wait_xfer_done(struct i2c_au1550_data *adap)
+{
+	u32	stat;
+	int	i;
+	volatile psc_smb_t	*sp;
+
+	sp = (volatile psc_smb_t *)(adap->psc_base);
+
+	/* Wait for Tx FIFO Underflow.
+	*/
+	for (i = 0; i < adap->xfer_timeout; i++) {
+		stat = sp->psc_smbevnt;
+		au_sync();
+		if ((stat & PSC_SMBEVNT_TU) != 0) {
+			/* Clear it.  */
+			sp->psc_smbevnt = PSC_SMBEVNT_TU;
+			au_sync();
+			return 0;
+		}
+		udelay(1);
+	}
+
+	return -ETIMEDOUT;
+}
+
+static int
+wait_ack(struct i2c_au1550_data *adap)
+{
+	u32	stat;
+	volatile psc_smb_t	*sp;
+
+	if (wait_xfer_done(adap))
+		return -ETIMEDOUT;
+
+	sp = (volatile psc_smb_t *)(adap->psc_base);
+
+	stat = sp->psc_smbevnt;
+	au_sync();
+
+	if ((stat & (PSC_SMBEVNT_DN | PSC_SMBEVNT_AN | PSC_SMBEVNT_AL)) != 0)
+		return -ETIMEDOUT;
+
+	return 0;
+}
+
+static int
+wait_master_done(struct i2c_au1550_data *adap)
+{
+	u32	stat;
+	int	i;
+	volatile psc_smb_t	*sp;
+
+	sp = (volatile psc_smb_t *)(adap->psc_base);
+
+	/* Wait for Master Done.
+	*/
+	for (i = 0; i < adap->xfer_timeout; i++) {
+		stat = sp->psc_smbevnt;
+		au_sync();
+		if ((stat & PSC_SMBEVNT_MD) != 0)
+			return 0;
+		udelay(1);
+	}
+
+	return -ETIMEDOUT;
+}
+
+static int
+do_address(struct i2c_au1550_data *adap, unsigned int addr, int rd)
+{
+	volatile psc_smb_t	*sp;
+	u32			stat;
+
+	sp = (volatile psc_smb_t *)(adap->psc_base);
+
+	/* Reset the FIFOs, clear events.
+	*/
+	sp->psc_smbpcr = PSC_SMBPCR_DC;
+	sp->psc_smbevnt = PSC_SMBEVNT_ALLCLR;
+	au_sync();
+	do {
+		stat = sp->psc_smbpcr;
+		au_sync();
+	} while ((stat & PSC_SMBPCR_DC) != 0);
+
+	/* Write out the i2c chip address and specify operation
+	*/
+	addr <<= 1;
+	if (rd)
+		addr |= 1;
+
+	/* Put byte into fifo, start up master.
+	*/
+	sp->psc_smbtxrx = addr;
+	au_sync();
+	sp->psc_smbpcr = PSC_SMBPCR_MS;
+	au_sync();
+	if (wait_ack(adap))
+		return -EIO;
+	return 0;
+}
+
+static u32
+wait_for_rx_byte(struct i2c_au1550_data *adap, u32 *ret_data)
+{
+	int	j;
+	u32	data, stat;
+	volatile psc_smb_t	*sp;
+
+	if (wait_xfer_done(adap))
+		return -EIO;
+
+	sp = (volatile psc_smb_t *)(adap->psc_base);
+
+	j =  adap->xfer_timeout * 100;
+	do {
+		j--;
+		if (j <= 0)
+			return -EIO;
+
+		stat = sp->psc_smbstat;
+		au_sync();
+		if ((stat & PSC_SMBSTAT_RE) == 0)
+			j = 0;
+		else
+			udelay(1);
+	} while (j > 0);
+	data = sp->psc_smbtxrx;
+	au_sync();
+	*ret_data = data;
+
+	return 0;
+}
+
+static int
+i2c_read(struct i2c_au1550_data *adap, unsigned char *buf,
+		    unsigned int len)
+{
+	int	i;
+	u32	data;
+	volatile psc_smb_t	*sp;
+
+	if (len == 0)
+		return 0;
+
+	/* A read is performed by stuffing the transmit fifo with
+	 * zero bytes for timing, waiting for bytes to appear in the
+	 * receive fifo, then reading the bytes.
+	 */
+
+	sp = (volatile psc_smb_t *)(adap->psc_base);
+
+	i = 0;
+	while (i < (len-1)) {
+		sp->psc_smbtxrx = 0;
+		au_sync();
+		if (wait_for_rx_byte(adap, &data))
+			return -EIO;
+
+		buf[i] = data;
+		i++;
+	}
+
+	/* The last byte has to indicate transfer done.
+	*/
+	sp->psc_smbtxrx = PSC_SMBTXRX_STP;
+	au_sync();
+	if (wait_master_done(adap))
+		return -EIO;
+
+	data = sp->psc_smbtxrx;
+	au_sync();
+	buf[i] = data;
+	return 0;
+}
+
+static int
+i2c_write(struct i2c_au1550_data *adap, unsigned char *buf,
+		     unsigned int len)
+{
+	int	i;
+	u32	data;
+	volatile psc_smb_t	*sp;
+
+	if (len == 0)
+		return 0;
+
+	sp = (volatile psc_smb_t *)(adap->psc_base);
+
+	i = 0;
+	while (i < (len-1)) {
+		data = buf[i];
+		sp->psc_smbtxrx = data;
+		au_sync();
+		if (wait_ack(adap))
+			return -EIO;
+		i++;
+	}
+
+	/* The last byte has to indicate transfer done.
+	*/
+	data = buf[i];
+	data |= PSC_SMBTXRX_STP;
+	sp->psc_smbtxrx = data;
+	au_sync();
+	if (wait_master_done(adap))
+		return -EIO;
+	return 0;
+}
+
+static int
+au1550_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg msgs[], int num)
+{
+	struct i2c_au1550_data *adap = i2c_adap->algo_data;
+	struct i2c_msg *p;
+	int i, err = 0;
+
+	for (i = 0; !err && i < num; i++) {
+		p = &msgs[i];
+		err = do_address(adap, p->addr, p->flags & I2C_M_RD);
+		if (err || !p->len)
+			continue;
+		if (p->flags & I2C_M_RD)
+			err = i2c_read(adap, p->buf, p->len);
+		else
+			err = i2c_write(adap, p->buf, p->len);
+	}
+
+	/* Return the number of messages processed, or the error code.
+	*/
+	if (err == 0)
+		err = num;
+	return err;
+}
+
+static u32
+au1550_func(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C;
+}
+
+static struct i2c_algorithm au1550_algo = {
+	.name		= "Au1550 algorithm",
+	.id		= I2C_ALGO_AU1550,
+	.master_xfer	= au1550_xfer,
+	.functionality	= au1550_func,
+};
+
+/*
+ * registering functions to load algorithms at runtime
+ * Prior to calling us, the 50MHz clock frequency and routing
+ * must have been set up for the PSC indicated by the adapter.
+ */
+int
+i2c_au1550_add_bus(struct i2c_adapter *i2c_adap)
+{
+	struct i2c_au1550_data *adap = i2c_adap->algo_data;
+	volatile psc_smb_t	*sp;
+	u32	stat;
+
+	i2c_adap->algo = &au1550_algo;
+
+	/* Now, set up the PSC for SMBus PIO mode.
+	*/
+	sp = (volatile psc_smb_t *)(adap->psc_base);
+	sp->psc_ctrl = PSC_CTRL_DISABLE;
+	au_sync();
+	sp->psc_sel = PSC_SEL_PS_SMBUSMODE;
+	sp->psc_smbcfg = 0;
+	au_sync();
+	sp->psc_ctrl = PSC_CTRL_ENABLE;
+	au_sync();
+	do {
+		stat = sp->psc_smbstat;
+		au_sync();
+	} while ((stat & PSC_SMBSTAT_SR) == 0);
+
+	sp->psc_smbcfg = (PSC_SMBCFG_RT_FIFO8 | PSC_SMBCFG_TT_FIFO8 |
+				PSC_SMBCFG_DD_DISABLE);
+
+	/* Divide by 8 to get a 6.25 MHz clock.  The later protocol
+	 * timings are based on this clock.
+	 */
+	sp->psc_smbcfg |= PSC_SMBCFG_SET_DIV(PSC_SMBCFG_DIV8);
+	sp->psc_smbmsk = PSC_SMBMSK_ALLMASK;
+	au_sync();
+
+	/* Set the protocol timer values.  See Table 71 in the
+	 * Au1550 Data Book for standard timing values.
+	 */
+	sp->psc_smbtmr = PSC_SMBTMR_SET_TH(0) | PSC_SMBTMR_SET_PS(15) | \
+		PSC_SMBTMR_SET_PU(15) | PSC_SMBTMR_SET_SH(15) | \
+		PSC_SMBTMR_SET_SU(15) | PSC_SMBTMR_SET_CL(15) | \
+		PSC_SMBTMR_SET_CH(15);
+	au_sync();
+
+	sp->psc_smbcfg |= PSC_SMBCFG_DE_ENABLE;
+	do {
+		stat = sp->psc_smbstat;
+		au_sync();
+	} while ((stat & PSC_SMBSTAT_DR) == 0);
+
+	return i2c_add_adapter(i2c_adap);
+}
+
+
+int
+i2c_au1550_del_bus(struct i2c_adapter *adap)
+{
+	return i2c_del_adapter(adap);
+}
+
+static int
+pb1550_reg(struct i2c_client *client)
+{
+	return 0;
+}
+
+static int
+pb1550_unreg(struct i2c_client *client)
+{
+	return 0;
+}
+
+static struct i2c_au1550_data pb1550_i2c_info = {
+	SMBUS_PSC_BASE, 200, 200
+};
+
+static struct i2c_adapter pb1550_board_adapter = {
+	name:              "pb1550 adapter",
+	id:                I2C_HW_AU1550_PSC,
+	algo:              NULL,
+	algo_data:         &pb1550_i2c_info,
+	client_register:   pb1550_reg,
+	client_unregister: pb1550_unreg,
+};
+
+/* BIG hack to support the control interface on the Wolfson WM8731
+ * audio codec on the Pb1550 board.  We get an address and two data
+ * bytes to write, create an i2c message, and send it across the
+ * i2c transfer function.  We do this here because we have access to
+ * the i2c adapter structure.
+ */
+static struct i2c_msg wm_i2c_msg;  /* We don't want this stuff on the stack */
+static	u8 i2cbuf[2];
+
+int
+pb1550_wm_codec_write(u8 addr, u8 reg, u8 val)
+{
+	wm_i2c_msg.addr = addr;
+	wm_i2c_msg.flags = 0;
+	wm_i2c_msg.buf = i2cbuf;
+	wm_i2c_msg.len = 2;
+	i2cbuf[0] = reg;
+	i2cbuf[1] = val;
+
+	return pb1550_board_adapter.algo->master_xfer(&pb1550_board_adapter, &wm_i2c_msg, 1);
+}
+
+static int __init
+i2c_au1550_init(void)
+{
+	printk(KERN_INFO "Au1550 I2C: ");
+
+	/* This is where we would set up a 50MHz clock source
+	 * and routing.  On the Pb1550, the SMBus is PSC2, which
+	 * uses a shared clock with USB.  This has been already
+	 * configured by Yamon as a 48MHz clock, close enough
+	 * for our work.
+	 */
+        if (i2c_au1550_add_bus(&pb1550_board_adapter) < 0) {
+		printk("failed to initialize.\n");
+                return -ENODEV;
+	}
+
+	printk("initialized.\n");
+	return 0;
+}
+
+static void __exit
+i2c_au1550_exit(void)
+{
+	i2c_au1550_del_bus(&pb1550_board_adapter);
+}
+
+MODULE_AUTHOR("Dan Malek, Embedded Edge, LLC.");
+MODULE_DESCRIPTION("SMBus adapter Alchemy pb1550");
+MODULE_LICENSE("GPL");
+
+module_init (i2c_au1550_init);
+module_exit (i2c_au1550_exit);

drivers/i2c/busses/i2c-au1550.h

+/*
+ * Copyright (C) 2004 Embedded Edge, LLC <dan@embeddededge.com>
+ * 2.6 port by Matt Porter <mporter@kernel.crashing.org>
+ *
+ *  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.
+ *
+ *  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.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#ifndef I2C_AU1550_H
+#define I2C_AU1550_H
+
+struct i2c_au1550_data {
+	u32	psc_base;
+	int	xfer_timeout;
+	int	ack_timeout;
+};
+
+int i2c_au1550_add_bus(struct i2c_adapter *);
+int i2c_au1550_del_bus(struct i2c_adapter *);
+
+#endif /* I2C_AU1550_H */

include/linux/i2c-id.h

@@ -200,6 +200,7 @@
 
 #define I2C_ALGO_SIBYTE 0x150000	/* Broadcom SiByte SOCs		*/
 #define I2C_ALGO_SGI	0x160000        /* SGI algorithm                */
+#define I2C_ALGO_AU1550	0x170000        /* Au1550 PSC algorithm		*/
 
 #define I2C_ALGO_EXP	0x800000	/* experimental			*/
 
@@ -274,6 +275,9 @@
 /* --- XSCALE on-chip adapters                          */
 #define I2C_HW_IOP3XX 0x00
 
+/* --- Au1550 PSC adapters adapters					*/
+#define I2C_HW_AU1550_PSC	0x00
+
 /* --- SMBus only adapters						*/
 #define I2C_HW_SMBUS_PIIX4	0x00
 #define I2C_HW_SMBUS_ALI15X3	0x01