drivers/sbus/char/bbc_i2c.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /* bbc_i2c.c: I2C low-level driver for BBC device on UltraSPARC-III
  *            platforms.
  *
  * Copyright (C) 2001, 2008 David S. Miller (davem@davemloft.net)
  */

 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/types.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
 #include <linux/wait.h>
 #include <linux/delay.h>
 #include <linux/interrupt.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
 #include <asm/bbc.h>
 #include <asm/io.h>

 #include "bbc_i2c.h"

 /* Convert this driver to use i2c bus layer someday... */
 #define I2C_PCF_PIN	0x80
 #define I2C_PCF_ESO	0x40
 #define I2C_PCF_ES1	0x20
 #define I2C_PCF_ES2	0x10
 #define I2C_PCF_ENI	0x08
 #define I2C_PCF_STA	0x04
 #define I2C_PCF_STO	0x02
 #define I2C_PCF_ACK	0x01

 #define I2C_PCF_START    (I2C_PCF_PIN | I2C_PCF_ESO | I2C_PCF_ENI | I2C_PCF_STA | I2C_PCF_ACK)
 #define I2C_PCF_STOP     (I2C_PCF_PIN | I2C_PCF_ESO | I2C_PCF_STO | I2C_PCF_ACK)
 #define I2C_PCF_REPSTART (              I2C_PCF_ESO | I2C_PCF_STA | I2C_PCF_ACK)
 #define I2C_PCF_IDLE     (I2C_PCF_PIN | I2C_PCF_ESO               | I2C_PCF_ACK)

 #define I2C_PCF_INI 0x40   /* 1 if not initialized */
 #define I2C_PCF_STS 0x20
 #define I2C_PCF_BER 0x10
 #define I2C_PCF_AD0 0x08
 #define I2C_PCF_LRB 0x08
 #define I2C_PCF_AAS 0x04
 #define I2C_PCF_LAB 0x02
 #define I2C_PCF_BB  0x01

 /* The BBC devices have two I2C controllers.  The first I2C controller
  * connects mainly to configuration proms (NVRAM, cpu configuration,
  * dimm types, etc.).  Whereas the second I2C controller connects to
  * environmental control devices such as fans and temperature sensors.
  * The second controller also connects to the smartcard reader, if present.
  */

 static void set_device_claimage(struct bbc_i2c_bus *bp, struct platform_device *op, int val)
 {
 	int i;

 	for (i = 0; i < NUM_CHILDREN; i++) {
 		if (bp->devs[i].device == op) {
 			bp->devs[i].client_claimed = val;
 			return;
 		}
 	}
 }

 #define claim_device(BP,ECHILD)		set_device_claimage(BP,ECHILD,1)
 #define release_device(BP,ECHILD)	set_device_claimage(BP,ECHILD,0)

 struct platform_device *bbc_i2c_getdev(struct bbc_i2c_bus *bp, int index)
 {
 	struct platform_device *op = NULL;
 	int curidx = 0, i;

 	for (i = 0; i < NUM_CHILDREN; i++) {
 		if (!(op = bp->devs[i].device))
 			break;
 		if (curidx == index)
 			goto out;
 		op = NULL;
 		curidx++;
 	}

 out:
 	if (curidx == index)
 		return op;
 	return NULL;
 }

 struct bbc_i2c_client *bbc_i2c_attach(struct bbc_i2c_bus *bp, struct platform_device *op)
 {
 	struct bbc_i2c_client *client;
 	const u32 *reg;

 	client = kzalloc(sizeof(*client), GFP_KERNEL);
 	if (!client)
 		return NULL;
 	client->bp = bp;
 	client->op = op;

 	reg = of_get_property(op->dev.of_node, "reg", NULL);
 	if (!reg) {
 		kfree(client);
 		return NULL;
 	}

 	client->bus = reg[0];
 	client->address = reg[1];

 	claim_device(bp, op);

 	return client;
 }

 void bbc_i2c_detach(struct bbc_i2c_client *client)
 {
 	struct bbc_i2c_bus *bp = client->bp;
 	struct platform_device *op = client->op;

 	release_device(bp, op);
 	kfree(client);
 }

 static int wait_for_pin(struct bbc_i2c_bus *bp, u8 *status)
 {
 	DECLARE_WAITQUEUE(wait, current);
 	int limit = 32;
 	int ret = 1;

 	bp->waiting = 1;
 	add_wait_queue(&bp->wq, &wait);
 	while (limit-- > 0) {
 		long val;

 		val = wait_event_interruptible_timeout(
 				bp->wq,
 				(((*status = readb(bp->i2c_control_regs + 0))
 				  & I2C_PCF_PIN) == 0),
 				msecs_to_jiffies(250));
 		if (val > 0) {
 			ret = 0;
 			break;
 		}
 	}
 	remove_wait_queue(&bp->wq, &wait);
 	bp->waiting = 0;

 	return ret;
 }

 int bbc_i2c_writeb(struct bbc_i2c_client *client, unsigned char val, int off)
 {
 	struct bbc_i2c_bus *bp = client->bp;
 	int address = client->address;
 	u8 status;
 	int ret = -1;

 	if (bp->i2c_bussel_reg != NULL)
 		writeb(client->bus, bp->i2c_bussel_reg);

 	writeb(address, bp->i2c_control_regs + 0x1);
 	writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
 	if (wait_for_pin(bp, &status))
 		goto out;

 	writeb(off, bp->i2c_control_regs + 0x1);
 	if (wait_for_pin(bp, &status) ||
 	    (status & I2C_PCF_LRB) != 0)
 		goto out;

 	writeb(val, bp->i2c_control_regs + 0x1);
 	if (wait_for_pin(bp, &status))
 		goto out;

 	ret = 0;

 out:
 	writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
 	return ret;
 }

 int bbc_i2c_readb(struct bbc_i2c_client *client, unsigned char *byte, int off)
 {
 	struct bbc_i2c_bus *bp = client->bp;
 	unsigned char address = client->address, status;
 	int ret = -1;

 	if (bp->i2c_bussel_reg != NULL)
 		writeb(client->bus, bp->i2c_bussel_reg);

 	writeb(address, bp->i2c_control_regs + 0x1);
 	writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
 	if (wait_for_pin(bp, &status))
 		goto out;

 	writeb(off, bp->i2c_control_regs + 0x1);
 	if (wait_for_pin(bp, &status) ||
 	    (status & I2C_PCF_LRB) != 0)
 		goto out;

 	writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);

 	address |= 0x1; /* READ */

 	writeb(address, bp->i2c_control_regs + 0x1);
 	writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
 	if (wait_for_pin(bp, &status))
 		goto out;

 	/* Set PIN back to one so the device sends the first
 	 * byte.
 	 */
 	(void) readb(bp->i2c_control_regs + 0x1);
 	if (wait_for_pin(bp, &status))
 		goto out;

 	writeb(I2C_PCF_ESO | I2C_PCF_ENI, bp->i2c_control_regs + 0x0);
 	*byte = readb(bp->i2c_control_regs + 0x1);
 	if (wait_for_pin(bp, &status))
 		goto out;

 	ret = 0;

 out:
 	writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
 	(void) readb(bp->i2c_control_regs + 0x1);

 	return ret;
 }

 int bbc_i2c_write_buf(struct bbc_i2c_client *client,
 		      char *buf, int len, int off)
 {
 	int ret = 0;

 	while (len > 0) {
 		ret = bbc_i2c_writeb(client, *buf, off);
 		if (ret < 0)
 			break;
 		len--;
 		buf++;
 		off++;
 	}
 	return ret;
 }

 int bbc_i2c_read_buf(struct bbc_i2c_client *client,
 		     char *buf, int len, int off)
 {
 	int ret = 0;

 	while (len > 0) {
 		ret = bbc_i2c_readb(client, buf, off);
 		if (ret < 0)
 			break;
 		len--;
 		buf++;
 		off++;
 	}

 	return ret;
 }

 EXPORT_SYMBOL(bbc_i2c_getdev);
 EXPORT_SYMBOL(bbc_i2c_attach);
 EXPORT_SYMBOL(bbc_i2c_detach);
 EXPORT_SYMBOL(bbc_i2c_writeb);
 EXPORT_SYMBOL(bbc_i2c_readb);
 EXPORT_SYMBOL(bbc_i2c_write_buf);
 EXPORT_SYMBOL(bbc_i2c_read_buf);

 static irqreturn_t bbc_i2c_interrupt(int irq, void *dev_id)
 {
 	struct bbc_i2c_bus *bp = dev_id;

 	/* PIN going from set to clear is the only event which
 	 * makes the i2c assert an interrupt.
 	 */
 	if (bp->waiting &&
 	    !(readb(bp->i2c_control_regs + 0x0) & I2C_PCF_PIN))
 		wake_up_interruptible(&bp->wq);

 	return IRQ_HANDLED;
 }

 static void reset_one_i2c(struct bbc_i2c_bus *bp)
 {
 	writeb(I2C_PCF_PIN, bp->i2c_control_regs + 0x0);
 	writeb(bp->own, bp->i2c_control_regs + 0x1);
 	writeb(I2C_PCF_PIN | I2C_PCF_ES1, bp->i2c_control_regs + 0x0);
 	writeb(bp->clock, bp->i2c_control_regs + 0x1);
 	writeb(I2C_PCF_IDLE, bp->i2c_control_regs + 0x0);
 }

 static struct bbc_i2c_bus * attach_one_i2c(struct platform_device *op, int index)
 {
 	struct bbc_i2c_bus *bp;
 	struct device_node *dp;
 	int entry;

 	bp = kzalloc(sizeof(*bp), GFP_KERNEL);
 	if (!bp)
 		return NULL;

 	INIT_LIST_HEAD(&bp->temps);
 	INIT_LIST_HEAD(&bp->fans);

 	bp->i2c_control_regs = of_ioremap(&op->resource[0], 0, 0x2, "bbc_i2c_regs");
 	if (!bp->i2c_control_regs)
 		goto fail;

 	if (op->num_resources == 2) {
 		bp->i2c_bussel_reg = of_ioremap(&op->resource[1], 0, 0x1, "bbc_i2c_bussel");
 		if (!bp->i2c_bussel_reg)
 			goto fail;
 	}

 	bp->waiting = 0;
 	init_waitqueue_head(&bp->wq);
 	if (request_irq(op->archdata.irqs[0], bbc_i2c_interrupt,
 			IRQF_SHARED, "bbc_i2c", bp))
 		goto fail;

 	bp->index = index;
 	bp->op = op;

 	spin_lock_init(&bp->lock);

 	entry = 0;
 	for (dp = op->dev.of_node->child;
 	     dp && entry < 8;
 	     dp = dp->sibling, entry++) {
 		struct platform_device *child_op;

 		child_op = of_find_device_by_node(dp);
 		bp->devs[entry].device = child_op;
 		bp->devs[entry].client_claimed = 0;
 	}

 	writeb(I2C_PCF_PIN, bp->i2c_control_regs + 0x0);
 	bp->own = readb(bp->i2c_control_regs + 0x01);
 	writeb(I2C_PCF_PIN | I2C_PCF_ES1, bp->i2c_control_regs + 0x0);
 	bp->clock = readb(bp->i2c_control_regs + 0x01);

 	printk(KERN_INFO "i2c-%d: Regs at %p, %d devices, own %02x, clock %02x.\n",
 	       bp->index, bp->i2c_control_regs, entry, bp->own, bp->clock);

 	reset_one_i2c(bp);

 	return bp;

 fail:
 	if (bp->i2c_bussel_reg)
 		of_iounmap(&op->resource[1], bp->i2c_bussel_reg, 1);
 	if (bp->i2c_control_regs)
 		of_iounmap(&op->resource[0], bp->i2c_control_regs, 2);
 	kfree(bp);
 	return NULL;
 }

 static int bbc_i2c_probe(struct platform_device *op)
 {
 	struct bbc_i2c_bus *bp;
 	int err, index = 0;

 	bp = attach_one_i2c(op, index);
 	if (!bp)
 		return -EINVAL;

 	err = bbc_envctrl_init(bp);
 	if (err) {
 		free_irq(op->archdata.irqs[0], bp);
 		if (bp->i2c_bussel_reg)
 			of_iounmap(&op->resource[0], bp->i2c_bussel_reg, 1);
 		if (bp->i2c_control_regs)
 			of_iounmap(&op->resource[1], bp->i2c_control_regs, 2);
 		kfree(bp);
 	} else {
 		dev_set_drvdata(&op->dev, bp);
 	}

 	return err;
 }

 static void bbc_i2c_remove(struct platform_device *op)
 {
 	struct bbc_i2c_bus *bp = dev_get_drvdata(&op->dev);

 	bbc_envctrl_cleanup(bp);

 	free_irq(op->archdata.irqs[0], bp);

 	if (bp->i2c_bussel_reg)
 		of_iounmap(&op->resource[0], bp->i2c_bussel_reg, 1);
 	if (bp->i2c_control_regs)
 		of_iounmap(&op->resource[1], bp->i2c_control_regs, 2);

 	kfree(bp);
 }

 static const struct of_device_id bbc_i2c_match[] = {
 	{
 		.name = "i2c",
 		.compatible = "SUNW,bbc-i2c",
 	},
 	{},
 };
 MODULE_DEVICE_TABLE(of, bbc_i2c_match);

 static struct platform_driver bbc_i2c_driver = {
 	.driver = {
 		.name = "bbc_i2c",
 		.of_match_table = bbc_i2c_match,
 	},
 	.probe		= bbc_i2c_probe,
 	.remove_new	= bbc_i2c_remove,
 };

 module_platform_driver(bbc_i2c_driver);

 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-only
	/* bbc_i2c.c: I2C low-level driver for BBC device on UltraSPARC-III
	* platforms.
	*
	* Copyright (C) 2001, 2008 David S. Miller (davem@davemloft.net)
	*/

	#include <linux/module.h>
	#include <linux/kernel.h>
	#include <linux/types.h>
	#include <linux/slab.h>
	#include <linux/sched.h>
	#include <linux/wait.h>
	#include <linux/delay.h>
	#include <linux/interrupt.h>
	#include <linux/of.h>
	#include <linux/of_platform.h>
	#include <linux/platform_device.h>
	#include <asm/bbc.h>
	#include <asm/io.h>

	#include "bbc_i2c.h"

	/* Convert this driver to use i2c bus layer someday... */
	#define I2C_PCF_PIN 0x80
	#define I2C_PCF_ESO 0x40
	#define I2C_PCF_ES1 0x20
	#define I2C_PCF_ES2 0x10
	#define I2C_PCF_ENI 0x08
	#define I2C_PCF_STA 0x04
	#define I2C_PCF_STO 0x02
	#define I2C_PCF_ACK 0x01

	#define I2C_PCF_START (I2C_PCF_PIN \| I2C_PCF_ESO \| I2C_PCF_ENI \| I2C_PCF_STA \| I2C_PCF_ACK)
	#define I2C_PCF_STOP (I2C_PCF_PIN \| I2C_PCF_ESO \| I2C_PCF_STO \| I2C_PCF_ACK)
	#define I2C_PCF_REPSTART ( I2C_PCF_ESO \| I2C_PCF_STA \| I2C_PCF_ACK)
	#define I2C_PCF_IDLE (I2C_PCF_PIN \| I2C_PCF_ESO \| I2C_PCF_ACK)

	#define I2C_PCF_INI 0x40 /* 1 if not initialized */
	#define I2C_PCF_STS 0x20
	#define I2C_PCF_BER 0x10
	#define I2C_PCF_AD0 0x08
	#define I2C_PCF_LRB 0x08
	#define I2C_PCF_AAS 0x04
	#define I2C_PCF_LAB 0x02
	#define I2C_PCF_BB 0x01

	/* The BBC devices have two I2C controllers. The first I2C controller
	* connects mainly to configuration proms (NVRAM, cpu configuration,
	* dimm types, etc.). Whereas the second I2C controller connects to
	* environmental control devices such as fans and temperature sensors.
	* The second controller also connects to the smartcard reader, if present.
	*/

	static void set_device_claimage(struct bbc_i2c_bus bp, struct platform_device op, int val)
	{
	int i;

	for (i = 0; i < NUM_CHILDREN; i++) {
	if (bp->devs[i].device == op) {
	bp->devs[i].client_claimed = val;
	return;
	}
	}
	}

	#define claim_device(BP,ECHILD) set_device_claimage(BP,ECHILD,1)
	#define release_device(BP,ECHILD) set_device_claimage(BP,ECHILD,0)

	struct platform_device bbc_i2c_getdev(struct bbc_i2c_bus bp, int index)
	{
	struct platform_device *op = NULL;
	int curidx = 0, i;

	for (i = 0; i < NUM_CHILDREN; i++) {
	if (!(op = bp->devs[i].device))
	break;
	if (curidx == index)
	goto out;
	op = NULL;
	curidx++;
	}

	out:
	if (curidx == index)
	return op;
	return NULL;
	}

	struct bbc_i2c_client bbc_i2c_attach(struct bbc_i2c_bus bp, struct platform_device *op)
	{
	struct bbc_i2c_client *client;
	const u32 *reg;

	client = kzalloc(sizeof(*client), GFP_KERNEL);
	if (!client)
	return NULL;
	client->bp = bp;
	client->op = op;

	reg = of_get_property(op->dev.of_node, "reg", NULL);
	if (!reg) {
	kfree(client);
	return NULL;
	}

	client->bus = reg[0];
	client->address = reg[1];

	claim_device(bp, op);

	return client;
	}

	void bbc_i2c_detach(struct bbc_i2c_client *client)
	{
	struct bbc_i2c_bus *bp = client->bp;
	struct platform_device *op = client->op;

	release_device(bp, op);
	kfree(client);
	}

	static int wait_for_pin(struct bbc_i2c_bus bp, u8 status)
	{
	DECLARE_WAITQUEUE(wait, current);
	int limit = 32;
	int ret = 1;

	bp->waiting = 1;
	add_wait_queue(&bp->wq, &wait);
	while (limit-- > 0) {
	long val;

	val = wait_event_interruptible_timeout(
	bp->wq,
	(((*status = readb(bp->i2c_control_regs + 0))
	& I2C_PCF_PIN) == 0),
	msecs_to_jiffies(250));
	if (val > 0) {
	ret = 0;
	break;
	}
	}
	remove_wait_queue(&bp->wq, &wait);
	bp->waiting = 0;

	return ret;
	}

	int bbc_i2c_writeb(struct bbc_i2c_client *client, unsigned char val, int off)
	{
	struct bbc_i2c_bus *bp = client->bp;
	int address = client->address;
	u8 status;
	int ret = -1;

	if (bp->i2c_bussel_reg != NULL)
	writeb(client->bus, bp->i2c_bussel_reg);

	writeb(address, bp->i2c_control_regs + 0x1);
	writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
	if (wait_for_pin(bp, &status))
	goto out;

	writeb(off, bp->i2c_control_regs + 0x1);
	if (wait_for_pin(bp, &status) \|\|
	(status & I2C_PCF_LRB) != 0)
	goto out;

	writeb(val, bp->i2c_control_regs + 0x1);
	if (wait_for_pin(bp, &status))
	goto out;

	ret = 0;

	out:
	writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
	return ret;
	}

	int bbc_i2c_readb(struct bbc_i2c_client client, unsigned char byte, int off)
	{
	struct bbc_i2c_bus *bp = client->bp;
	unsigned char address = client->address, status;
	int ret = -1;

	if (bp->i2c_bussel_reg != NULL)
	writeb(client->bus, bp->i2c_bussel_reg);

	writeb(address, bp->i2c_control_regs + 0x1);
	writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
	if (wait_for_pin(bp, &status))
	goto out;

	writeb(off, bp->i2c_control_regs + 0x1);
	if (wait_for_pin(bp, &status) \|\|
	(status & I2C_PCF_LRB) != 0)
	goto out;

	writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);

	address \|= 0x1; /* READ */

	writeb(address, bp->i2c_control_regs + 0x1);
	writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
	if (wait_for_pin(bp, &status))
	goto out;

	/* Set PIN back to one so the device sends the first
	* byte.
	*/
	(void) readb(bp->i2c_control_regs + 0x1);
	if (wait_for_pin(bp, &status))
	goto out;

	writeb(I2C_PCF_ESO \| I2C_PCF_ENI, bp->i2c_control_regs + 0x0);
	*byte = readb(bp->i2c_control_regs + 0x1);
	if (wait_for_pin(bp, &status))
	goto out;

	ret = 0;

	out:
	writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
	(void) readb(bp->i2c_control_regs + 0x1);

	return ret;
	}

	int bbc_i2c_write_buf(struct bbc_i2c_client *client,
	char *buf, int len, int off)
	{
	int ret = 0;

	while (len > 0) {
	ret = bbc_i2c_writeb(client, *buf, off);
	if (ret < 0)
	break;
	len--;
	buf++;
	off++;
	}
	return ret;
	}

	int bbc_i2c_read_buf(struct bbc_i2c_client *client,
	char *buf, int len, int off)
	{
	int ret = 0;

	while (len > 0) {
	ret = bbc_i2c_readb(client, buf, off);
	if (ret < 0)
	break;
	len--;
	buf++;
	off++;
	}

	return ret;
	}

	EXPORT_SYMBOL(bbc_i2c_getdev);
	EXPORT_SYMBOL(bbc_i2c_attach);
	EXPORT_SYMBOL(bbc_i2c_detach);
	EXPORT_SYMBOL(bbc_i2c_writeb);
	EXPORT_SYMBOL(bbc_i2c_readb);
	EXPORT_SYMBOL(bbc_i2c_write_buf);
	EXPORT_SYMBOL(bbc_i2c_read_buf);

	static irqreturn_t bbc_i2c_interrupt(int irq, void *dev_id)
	{
	struct bbc_i2c_bus *bp = dev_id;

	/* PIN going from set to clear is the only event which
	* makes the i2c assert an interrupt.
	*/
	if (bp->waiting &&
	!(readb(bp->i2c_control_regs + 0x0) & I2C_PCF_PIN))
	wake_up_interruptible(&bp->wq);

	return IRQ_HANDLED;
	}

	static void reset_one_i2c(struct bbc_i2c_bus *bp)
	{
	writeb(I2C_PCF_PIN, bp->i2c_control_regs + 0x0);
	writeb(bp->own, bp->i2c_control_regs + 0x1);
	writeb(I2C_PCF_PIN \| I2C_PCF_ES1, bp->i2c_control_regs + 0x0);
	writeb(bp->clock, bp->i2c_control_regs + 0x1);
	writeb(I2C_PCF_IDLE, bp->i2c_control_regs + 0x0);
	}

	static struct bbc_i2c_bus * attach_one_i2c(struct platform_device *op, int index)
	{
	struct bbc_i2c_bus *bp;
	struct device_node *dp;
	int entry;

	bp = kzalloc(sizeof(*bp), GFP_KERNEL);
	if (!bp)
	return NULL;

	INIT_LIST_HEAD(&bp->temps);
	INIT_LIST_HEAD(&bp->fans);

	bp->i2c_control_regs = of_ioremap(&op->resource[0], 0, 0x2, "bbc_i2c_regs");
	if (!bp->i2c_control_regs)
	goto fail;

	if (op->num_resources == 2) {
	bp->i2c_bussel_reg = of_ioremap(&op->resource[1], 0, 0x1, "bbc_i2c_bussel");
	if (!bp->i2c_bussel_reg)
	goto fail;
	}

	bp->waiting = 0;
	init_waitqueue_head(&bp->wq);
	if (request_irq(op->archdata.irqs[0], bbc_i2c_interrupt,
	IRQF_SHARED, "bbc_i2c", bp))
	goto fail;

	bp->index = index;
	bp->op = op;

	spin_lock_init(&bp->lock);

	entry = 0;
	for (dp = op->dev.of_node->child;
	dp && entry < 8;
	dp = dp->sibling, entry++) {
	struct platform_device *child_op;

	child_op = of_find_device_by_node(dp);
	bp->devs[entry].device = child_op;
	bp->devs[entry].client_claimed = 0;
	}

	writeb(I2C_PCF_PIN, bp->i2c_control_regs + 0x0);
	bp->own = readb(bp->i2c_control_regs + 0x01);
	writeb(I2C_PCF_PIN \| I2C_PCF_ES1, bp->i2c_control_regs + 0x0);
	bp->clock = readb(bp->i2c_control_regs + 0x01);

	printk(KERN_INFO "i2c-%d: Regs at %p, %d devices, own %02x, clock %02x.\n",
	bp->index, bp->i2c_control_regs, entry, bp->own, bp->clock);

	reset_one_i2c(bp);

	return bp;

	fail:
	if (bp->i2c_bussel_reg)
	of_iounmap(&op->resource[1], bp->i2c_bussel_reg, 1);
	if (bp->i2c_control_regs)
	of_iounmap(&op->resource[0], bp->i2c_control_regs, 2);
	kfree(bp);
	return NULL;
	}

	static int bbc_i2c_probe(struct platform_device *op)
	{
	struct bbc_i2c_bus *bp;
	int err, index = 0;

	bp = attach_one_i2c(op, index);
	if (!bp)
	return -EINVAL;

	err = bbc_envctrl_init(bp);
	if (err) {
	free_irq(op->archdata.irqs[0], bp);
	if (bp->i2c_bussel_reg)
	of_iounmap(&op->resource[0], bp->i2c_bussel_reg, 1);
	if (bp->i2c_control_regs)
	of_iounmap(&op->resource[1], bp->i2c_control_regs, 2);
	kfree(bp);
	} else {
	dev_set_drvdata(&op->dev, bp);
	}

	return err;
	}

	static void bbc_i2c_remove(struct platform_device *op)
	{
	struct bbc_i2c_bus *bp = dev_get_drvdata(&op->dev);

	bbc_envctrl_cleanup(bp);

	free_irq(op->archdata.irqs[0], bp);

	if (bp->i2c_bussel_reg)
	of_iounmap(&op->resource[0], bp->i2c_bussel_reg, 1);
	if (bp->i2c_control_regs)
	of_iounmap(&op->resource[1], bp->i2c_control_regs, 2);

	kfree(bp);
	}

	static const struct of_device_id bbc_i2c_match[] = {
	{
	.name = "i2c",
	.compatible = "SUNW,bbc-i2c",
	},
	{},
	};
	MODULE_DEVICE_TABLE(of, bbc_i2c_match);

	static struct platform_driver bbc_i2c_driver = {
	.driver = {
	.name = "bbc_i2c",
	.of_match_table = bbc_i2c_match,
	},
	.probe = bbc_i2c_probe,
	.remove_new = bbc_i2c_remove,
	};

	module_platform_driver(bbc_i2c_driver);

	MODULE_LICENSE("GPL");