Subject: [PATCH] I2C driver for MPC107/824x/85xx/52xx

From: Adrian Cox <[email-masked]>
Date: Fri, 30 Jul 2004 16:33:32 +0100

This is the latest version of my driver for the I2C controller in the
MPC107 and related chips.

Since last posting the driver has been tested on MPC5200, where it works
only when interrupts are disabled. I have positive results for MPC107
and MPC8540. There's also a bug fix in error detection on I2C reads,
updated timer handling, and clock initialisation is now done only once.

I plan to send this version to Greg KH unless I hear objections in the
next few days.

- Adrian Cox
Humboldt Solutions Ltd.

# This is a BitKeeper generated diff -Nru style patch.
#
# ChangeSet
#   2004/07/30 15:56:50+01:00 [email-masked]
#   Fix detection of I2C errors during device address on i2c-mpc.
#
# drivers/i2c/busses/i2c-mpc.c
#   2004/07/30 15:56:34+01:00 [email-masked] +10 -8
#   Fix detection of errors while writing device address.
#
# ChangeSet
#   2004/07/07 13:57:51+01:00 [email-masked]
#   Added 52xx support.
#
# include/asm-ppc/fsl_ocp.h
#   2004/07/07 13:57:41+01:00 [email-masked] +1 -1
#   Added 52xx support.
#
# drivers/i2c/busses/i2c-mpc.c
#   2004/07/07 13:57:41+01:00 [email-masked] +10 -2
#   Added 52xx support.
#
# drivers/i2c/busses/Kconfig
#   2004/07/07 13:57:40+01:00 [email-masked] +3 -2
#   Added 52xx support.
#
# ChangeSet
#   2004/07/01 22:10:01+01:00 [email-masked]
#   Switch to time_after for jiffies calculations
#
# drivers/i2c/busses/i2c-mpc.c
#   2004/07/01 22:09:50+01:00 [email-masked] +3 -3
#   Switch to time_after for jiffies calculations
#
# ChangeSet
#   2004/07/01 22:04:45+01:00 [email-masked]
#   Switch from readl/writel to readb/writeb for MPC85xx compatibility.
#
# drivers/i2c/busses/i2c-mpc.c
#   2004/07/01 22:04:32+01:00 [email-masked] +17 -17
#   Switch from readl/writel to readb/writeb for MPC85xx compatibility.
#
# ChangeSet
#   2004/07/01 17:53:05+01:00 [email-masked]
#   Add I2C driver for Motorola I2C
#
# drivers/i2c/busses/i2c-mpc.c
#   2004/07/01 17:52:55+01:00 [email-masked] +410 -0
#
# drivers/i2c/busses/i2c-mpc.c
#   2004/07/01 17:52:55+01:00 [email-masked] +0 -0
#   BitKeeper file /home/adrian/kernels/sa107-2.6/for-upstream/drivers/i2c/busses/i2c-mpc.c
#
# drivers/i2c/busses/Makefile
#   2004/07/01 17:52:55+01:00 [email-masked] +1 -0
#   Add I2C driver for Motorola I2C
#
# drivers/i2c/busses/Kconfig
#   2004/07/01 17:52:54+01:00 [email-masked] +11 -0
#   Add I2C driver for Motorola I2C
#
diff -Nru a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
--- a/drivers/i2c/busses/Kconfig	Fri Jul 30 16:11:48 2004
+++ b/drivers/i2c/busses/Kconfig	Fri Jul 30 16:11:48 2004
@@ -396,4 +396,16 @@
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-voodoo3.

+config I2C_MPC
+	tristate "MPC107/824x/85xx/52xx"
+	depends on I2C && FSL_OCP
+	help
+	  If you say yes to this option, support will be included for the
+	  built-in I2C interface on the MPC107/Tsi107/MPC8240/MPC8245 and
+	  MPC85xx family processors. The driver may also work on 52xx
+	  family processors, though interrupts are known not to work.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called i2c-mpc.
+
 endmenu
diff -Nru a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
--- a/drivers/i2c/busses/Makefile	Fri Jul 30 16:11:48 2004
+++ b/drivers/i2c/busses/Makefile	Fri Jul 30 16:11:48 2004
@@ -32,6 +32,7 @@
 obj-$(CONFIG_I2C_VOODOO3)	+= i2c-voodoo3.o
 obj-$(CONFIG_SCx200_ACB)	+= scx200_acb.o
 obj-$(CONFIG_SCx200_I2C)	+= scx200_i2c.o
+obj-$(CONFIG_I2C_MPC)	+= i2c-mpc.o

 ifeq ($(CONFIG_I2C_DEBUG_BUS),y)
 EXTRA_CFLAGS += -DDEBUG
diff -Nru a/drivers/i2c/busses/i2c-mpc.c b/drivers/i2c/busses/i2c-mpc.c
--- /dev/null	Wed Dec 31 16:00:00 1969
+++ b/drivers/i2c/busses/i2c-mpc.c	Fri Jul 30 16:11:48 2004
@@ -0,0 +1,420 @@
+/*
+ * (C) Copyright 2003-2004
+ * Humboldt Solutions Ltd, [email-masked].
+
+ * This is a combined i2c adapter and algorithm driver for the
+ * MPC107/Tsi107 PowerPC northbridge and processors that include
+ * the same I2C unit (8240, 8245, 85xx).
+ *
+ * Release 0.6
+ *
+ * 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/kernel.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/init.h>
+#include <linux/pci.h>
+#include <asm/io.h>
+#include <asm/ocp.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+
+#ifdef CONFIG_I2C_DEBUG_BUS
+#define DPRINTK(args...) printk(KERN_DEBUG __FILE__": " args)
+#else
+#define DPRINTK(args...)
+#endif
+
+
+#define MPC_I2C_ADDR  0x00
+#define MPC_I2C_FDR 	0x04
+#define MPC_I2C_CR	0x08
+#define MPC_I2C_SR	0x0c
+#define MPC_I2C_DR	0x10
+#define MPC_I2C_DFSRR 0x14
+#define MPC_I2C_REGION 0x20
+
+#define CCR_MEN  0x80
+#define CCR_MIEN 0x40
+#define CCR_MSTA 0x20
+#define CCR_MTX  0x10
+#define CCR_TXAK 0x08
+#define CCR_RSTA 0x04
+
+#define CSR_MCF  0x80
+#define CSR_MAAS 0x40
+#define CSR_MBB  0x20
+#define CSR_MAL  0x10
+#define CSR_SRW  0x04
+#define CSR_MIF  0x02
+#define CSR_RXAK 0x01
+
+struct mpc_i2c {
+	char *base;
+	struct ocp_def *ocpdef;
+	u32 interrupt;
+	wait_queue_head_t queue;
+	struct i2c_adapter adap;
+};
+
+static __inline__ void writeccr(struct mpc_i2c *i2c, u32 x)
+{
+	writeb(x, i2c->base + MPC_I2C_CR);
+}
+
+static irqreturn_t mpc_i2c_isr(int irq, void *dev_id, struct pt_regs * regs)
+{
+	struct mpc_i2c *i2c = dev_id;
+	if (readb(i2c->base + MPC_I2C_SR) & CSR_MIF) {
+		/* Read again to allow register to stabilise */
+		i2c->interrupt = readb(i2c->base + MPC_I2C_SR);
+		writeb(0, i2c->base + MPC_I2C_SR);
+		wake_up_interruptible(&i2c->queue);
+	}
+	return IRQ_HANDLED;
+}
+
+static int i2c_wait(struct mpc_i2c *i2c, unsigned timeout, int writing)
+{
+	DECLARE_WAITQUEUE(wait, current);
+        unsigned long orig_jiffies = jiffies;
+        u32 x;
+	int result = 0;
+
+	if (i2c->ocpdef->irq == OCP_IRQ_NA) {
+		while(! (readb(i2c->base + MPC_I2C_SR) & CSR_MIF)) {
+			schedule();
+			if (time_after(jiffies, orig_jiffies + timeout)) {
+				DPRINTK("I2C: timeout\n");
+				result = -EIO;
+				break;
+			}
+		}
+		x = readb(i2c->base + MPC_I2C_SR);
+		writeb(0, i2c->base + MPC_I2C_SR);
+	} else {
+		add_wait_queue(&i2c->queue, &wait);
+		while ( ! (i2c->interrupt & CSR_MIF)) {
+			set_current_state(TASK_INTERRUPTIBLE);
+			if (signal_pending(current)) {
+				DPRINTK("I2C: Interrupted\n");
+				result = -EINTR;
+				break;
+			}
+			if (time_after(jiffies, orig_jiffies + timeout)) {
+				DPRINTK("I2C: timeout\n");
+				result = -EIO;
+				break;
+			}
+			schedule_timeout(timeout);
+		}
+		current->state = TASK_RUNNING;
+		remove_wait_queue(&i2c->queue, &wait);
+		x = i2c->interrupt;
+		i2c->interrupt = 0;
+	}
+
+	if (result < -0)
+	    return result;
+
+	if (! (x & CSR_MCF))
+	{
+	    DPRINTK("I2C: unfinished\n");
+	    return -EIO;
+	}
+
+        if (x & CSR_MAL)
+	{
+	    	DPRINTK("I2C: MAL\n");
+                return -EIO;
+	}
+
+        if (writing && (x & CSR_RXAK)) {
+                DPRINTK("I2C: No RXAK\n");
+                /* generate stop */
+                writeccr(i2c, CCR_MEN);
+                return -EIO;
+        }
+        return 0;
+}
+
+static void mpc_i2c_setclock(struct mpc_i2c *i2c)
+{
+	struct ocp_fs_i2c_data *i2c_data = i2c->ocpdef->additions;
+        /* Set clock and filters */
+	if (i2c_data && (i2c_data->flags & FS_I2C_SEPARATE_DFSRR)) {
+		writeb(0x31, i2c->base + MPC_I2C_FDR);
+		writeb(0x10, i2c->base + MPC_I2C_DFSRR);
+	} else if (i2c_data && (i2c_data->flags & FS_I2C_CLOCK_5200))
+		writeb(0x3f, i2c->base + MPC_I2C_FDR);
+	else
+		writel(0x1031, i2c->base + MPC_I2C_FDR);
+}
+
+static void mpc_i2c_start(struct mpc_i2c *i2c)
+{
+        /* Clear arbitration */
+        writeb(0, i2c->base + MPC_I2C_SR);
+       	/* Start with MEN */
+	writeccr(i2c, CCR_MEN);
+}
+
+static void mpc_i2c_stop(struct mpc_i2c *i2c)
+{
+	writeccr(i2c, CCR_MEN);
+}
+
+static int mpc_write(struct mpc_i2c *i2c, int target,
+			const u8 *data, int length, int restart)
+{
+        int i;
+        unsigned timeout = HZ;
+    	u32 flags = restart ? CCR_RSTA : 0;
+
+	/* Start with MEN */
+	if (! restart)
+		writeccr(i2c, CCR_MEN);
+	/* Start as master */
+	writeccr(i2c, CCR_MIEN | CCR_MEN |
+		      CCR_MSTA | CCR_MTX | flags);
+	/* Write target byte */
+	writeb((target << 1), i2c->base + MPC_I2C_DR);
+
+	if (i2c_wait(i2c, timeout, 1) < 0)
+	    return -1;
+
+        for(i = 0; i < length; i++) {
+	        /* Write data byte */
+	        writeb(data[i], i2c->base + MPC_I2C_DR);
+
+	        if (i2c_wait(i2c, timeout, 1) < 0)
+	            return -1;
+        }
+
+        return 0;
+}
+
+static int mpc_read(struct mpc_i2c *i2c, int target,
+		       u8 *data, int length, int restart)
+{
+    	unsigned timeout = HZ;
+    	int i;
+    	u32 flags = restart ? CCR_RSTA : 0;
+
+	/* Start with MEN */
+	if (! restart)
+		writeccr(i2c, CCR_MEN);
+	/* Switch to read - restart */
+	writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA |
+		      CCR_MTX | flags);
+	/* Write target address byte - this time with the read flag set */
+	writeb((target << 1) | 1, i2c->base + MPC_I2C_DR);
+
+	if (i2c_wait(i2c, timeout, 1) < 0)
+	    return -1;
+
+	if (length) {
+		if (length == 1)
+			writeccr(i2c, CCR_MIEN| CCR_MEN |
+				 CCR_MSTA | CCR_TXAK);
+		else
+			writeccr(i2c, CCR_MIEN| CCR_MEN | CCR_MSTA);
+		/* Dummy read */
+		readb(i2c->base + MPC_I2C_DR);
+	}
+
+	for(i = 0; i < length; i++) {
+		if (i2c_wait(i2c, timeout, 0) < 0)
+			return -1;
+
+		/* Generate txack on next to last byte */
+		if (i == length - 2)
+			writeccr(i2c, CCR_MIEN | CCR_MEN |
+				      CCR_MSTA | CCR_TXAK);
+		/* Generate stop on last byte */
+		if (i == length - 1)
+			writeccr(i2c, CCR_MIEN | CCR_MEN |
+				      CCR_TXAK);
+		data[i] = readb(i2c->base + MPC_I2C_DR);
+	}
+
+	return length;
+}
+
+static int mpc_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
+	                   int num)
+{
+	struct i2c_msg *pmsg;
+	int i;
+	int ret=0;
+        unsigned long orig_jiffies = jiffies;
+	struct mpc_i2c *i2c = i2c_get_adapdata(adap);
+
+        mpc_i2c_start(i2c);
+
+	/* Allow bus up to 1s to become not busy */
+	while(readb(i2c->base + MPC_I2C_SR) & CSR_MBB) {
+                if (signal_pending(current))
+		{
+			DPRINTK("I2C: Interrupted\n");
+                        return -EINTR;
+		}
+                if (time_after(jiffies, orig_jiffies + HZ))
+		{
+		    	printk("I2C: timeout\n");
+                        return -EIO;
+		}
+                schedule();
+        }
+
+	for (i = 0;ret >= 0 && i < num; i++) {
+		pmsg = &msgs[i];
+		DPRINTK("Doing %s %d bytes to 0x%02x - %d of %d messages\n",
+		     pmsg->flags & I2C_M_RD ? "read" : "write",
+                     pmsg->len, pmsg->addr, i + 1, num);
+		if (pmsg->flags & I2C_M_RD)
+                        ret = mpc_read(i2c, pmsg->addr, pmsg->buf, pmsg->len, i);
+                else
+                        ret = mpc_write(i2c, pmsg->addr, pmsg->buf, pmsg->len, i);
+        }
+        mpc_i2c_stop(i2c);
+        return (ret < 0) ? ret : num;
+}
+
+static u32 mpc_functionality(struct i2c_adapter *adap)
+{
+        return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static struct i2c_algorithm mpc_algo = {
+	.name = "MPC algorithm",
+	.id = I2C_ALGO_MPC107,
+	.master_xfer = mpc_xfer,
+	.functionality = mpc_functionality,
+};
+
+static struct i2c_adapter mpc_ops = {
+	.owner = THIS_MODULE,
+	.name = "MPC adapter",
+	.id = I2C_ALGO_MPC107 | I2C_HW_MPC107,
+	.algo = &mpc_algo,
+	.class = I2C_CLASS_HWMON,
+	.timeout = 1,
+	.retries = 1
+};
+
+static int __devinit mpc_i2c_probe(struct ocp_device *ocp)
+{
+	int result = 0;
+	struct mpc_i2c *i2c;
+
+	if (!(i2c = kmalloc(sizeof(*i2c), GFP_KERNEL))){
+		return -ENOMEM;
+	}
+	i2c->ocpdef = ocp->def;
+	init_waitqueue_head(&i2c->queue);
+
+	if (! request_mem_region(ocp->def->paddr, MPC_I2C_REGION,
+		                 "i2c-mpc")) {
+		printk(KERN_ERR "i2c-mpc - resource unavailable\n");
+		return -ENODEV;
+	}
+
+	i2c->base = ioremap(ocp->def->paddr, MPC_I2C_REGION);
+
+	if (! i2c->base) {
+		printk(KERN_ERR "i2c-mpc - failed to map controller\n");
+		result = -ENOMEM;
+		goto fail_map;
+	}
+
+	if (ocp->def->irq != OCP_IRQ_NA)
+		if ((result = request_irq(ocp->def->irq, mpc_i2c_isr,
+					  0, "i2c-mpc", i2c)) < 0) {
+			printk(KERN_ERR "i2c-mpc - failed to attach interrupt\n");
+			goto fail_irq;
+		}
+
+	i2c->adap = mpc_ops;
+	i2c_set_adapdata(&i2c->adap, i2c);
+	if ((result = i2c_add_adapter(&i2c->adap)) < 0) {
+		printk(KERN_ERR "i2c-mpc - failed to add adapter\n");
+		goto fail_add;
+	}
+
+	mpc_i2c_setclock(i2c);
+	ocp_set_drvdata(ocp, i2c);
+	return result;
+
+fail_add:
+	if (ocp->def->irq != OCP_IRQ_NA)
+		free_irq(ocp->def->irq, 0);
+fail_irq:
+	iounmap(i2c->base);
+fail_map:
+	release_mem_region(ocp->def->paddr, MPC_I2C_REGION);
+	kfree(i2c);
+	return result;
+}
+static void __devexit mpc_i2c_remove(struct ocp_device *ocp)
+{
+	struct mpc_i2c *i2c = ocp_get_drvdata(ocp);
+	ocp_set_drvdata(ocp, NULL);
+	i2c_del_adapter(&i2c->adap);
+
+	if (ocp->def->irq != OCP_IRQ_NA)
+		free_irq(i2c->ocpdef->irq, i2c);
+	iounmap(i2c->base);
+	release_mem_region(i2c->ocpdef->paddr, MPC_I2C_REGION);
+	kfree(i2c);
+}
+
+static struct ocp_device_id mpc_iic_ids[] __devinitdata =
+{
+	{ .vendor = OCP_VENDOR_FREESCALE, .function = OCP_FUNC_IIC },
+	{ .vendor = OCP_VENDOR_INVALID }
+};
+
+MODULE_DEVICE_TABLE(ocp, mpc_iic_ids);
+
+static struct ocp_driver mpc_iic_driver =
+{
+	.name 		= "iic",
+	.id_table	= mpc_iic_ids,
+	.probe		= mpc_i2c_probe,
+	.remove		= __devexit_p(mpc_i2c_remove)
+};
+
+static int __init iic_init(void)
+{
+	return ocp_register_driver(&mpc_iic_driver);
+}
+
+static void __exit iic_exit(void)
+{
+	ocp_unregister_driver(&mpc_iic_driver);
+}
+
+module_init(iic_init);
+module_exit(iic_exit);
+
+
+MODULE_AUTHOR("Adrian Cox <[email-masked]>");
+MODULE_DESCRIPTION("I2C-Bus adapter for MPC107 bridge and MPC824x/85xx processors");
+MODULE_LICENSE("GPL");
diff -Nru a/include/asm-ppc/fsl_ocp.h b/include/asm-ppc/fsl_ocp.h
--- a/include/asm-ppc/fsl_ocp.h	Fri Jul 30 16:11:48 2004
+++ b/include/asm-ppc/fsl_ocp.h	Fri Jul 30 16:11:48 2004
@@ -48,7 +48,7 @@

 /* Flags for I2C */
 #define FS_I2C_SEPARATE_DFSRR	0x02
-#define FS_I2C_32BIT		0x01
+#define FS_I2C_CLOCK_5200	0x01

 #endif	/* __ASM_FS_OCP_H__ */
 #endif	/* __KERNEL__ */