drivers/i2c/busses/i2c-ocores.c - linux - Git at Google

 /*
  * i2c-ocores.c: I2C bus driver for OpenCores I2C controller
  * (http://www.opencores.org/projects.cgi/web/i2c/overview).
  *
  * Peter Korsgaard <jacmet@sunsite.dk>
  *
  * This file is licensed under the terms of the GNU General Public License
  * version 2.  This program is licensed "as is" without any warranty of any
  * kind, whether express or implied.
  */

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/sched.h>
 #include <linux/init.h>
 #include <linux/errno.h>
 #include <linux/platform_device.h>
 #include <linux/i2c.h>
 #include <linux/interrupt.h>
 #include <linux/wait.h>
 #include <linux/i2c-ocores.h>
 #include <asm/io.h>

 struct ocores_i2c {
 	void __iomem *base;
 	int regstep;
 	wait_queue_head_t wait;
 	struct i2c_adapter adap;
 	struct i2c_msg *msg;
 	int pos;
 	int nmsgs;
 	int state; /* see STATE_ */
 };

 /* registers */
 #define OCI2C_PRELOW		0
 #define OCI2C_PREHIGH		1
 #define OCI2C_CONTROL		2
 #define OCI2C_DATA		3
 #define OCI2C_CMD		4 /* write only */
 #define OCI2C_STATUS		4 /* read only, same address as OCI2C_CMD */

 #define OCI2C_CTRL_IEN		0x40
 #define OCI2C_CTRL_EN		0x80

 #define OCI2C_CMD_START		0x91
 #define OCI2C_CMD_STOP		0x41
 #define OCI2C_CMD_READ		0x21
 #define OCI2C_CMD_WRITE		0x11
 #define OCI2C_CMD_READ_ACK	0x21
 #define OCI2C_CMD_READ_NACK	0x29
 #define OCI2C_CMD_IACK		0x01

 #define OCI2C_STAT_IF		0x01
 #define OCI2C_STAT_TIP		0x02
 #define OCI2C_STAT_ARBLOST	0x20
 #define OCI2C_STAT_BUSY		0x40
 #define OCI2C_STAT_NACK		0x80

 #define STATE_DONE		0
 #define STATE_START		1
 #define STATE_WRITE		2
 #define STATE_READ		3
 #define STATE_ERROR		4

 static inline void oc_setreg(struct ocores_i2c *i2c, int reg, u8 value)
 {
 	iowrite8(value, i2c->base + reg * i2c->regstep);
 }

 static inline u8 oc_getreg(struct ocores_i2c *i2c, int reg)
 {
 	return ioread8(i2c->base + reg * i2c->regstep);
 }

 static void ocores_process(struct ocores_i2c *i2c)
 {
 	struct i2c_msg *msg = i2c->msg;
 	u8 stat = oc_getreg(i2c, OCI2C_STATUS);

 	if ((i2c->state == STATE_DONE) || (i2c->state == STATE_ERROR)) {
 		/* stop has been sent */
 		oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK);
 		wake_up(&i2c->wait);
 		return;
 	}

 	/* error? */
 	if (stat & OCI2C_STAT_ARBLOST) {
 		i2c->state = STATE_ERROR;
 		oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
 		return;
 	}

 	if ((i2c->state == STATE_START) || (i2c->state == STATE_WRITE)) {
 		i2c->state =
 			(msg->flags & I2C_M_RD) ? STATE_READ : STATE_WRITE;

 		if (stat & OCI2C_STAT_NACK) {
 			i2c->state = STATE_ERROR;
 			oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
 			return;
 		}
 	} else
 		msg->buf[i2c->pos++] = oc_getreg(i2c, OCI2C_DATA);

 	/* end of msg? */
 	if (i2c->pos == msg->len) {
 		i2c->nmsgs--;
 		i2c->msg++;
 		i2c->pos = 0;
 		msg = i2c->msg;

 		if (i2c->nmsgs) {	/* end? */
 			/* send start? */
 			if (!(msg->flags & I2C_M_NOSTART)) {
 				u8 addr = (msg->addr << 1);

 				if (msg->flags & I2C_M_RD)
 					addr |= 1;

 				i2c->state = STATE_START;

 				oc_setreg(i2c, OCI2C_DATA, addr);
 				oc_setreg(i2c, OCI2C_CMD,  OCI2C_CMD_START);
 				return;
 			} else
 				i2c->state = (msg->flags & I2C_M_RD)
 					? STATE_READ : STATE_WRITE;
 		} else {
 			i2c->state = STATE_DONE;
 			oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
 			return;
 		}
 	}

 	if (i2c->state == STATE_READ) {
 		oc_setreg(i2c, OCI2C_CMD, i2c->pos == (msg->len-1) ?
 			  OCI2C_CMD_READ_NACK : OCI2C_CMD_READ_ACK);
 	} else {
 		oc_setreg(i2c, OCI2C_DATA, msg->buf[i2c->pos++]);
 		oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_WRITE);
 	}
 }

 static irqreturn_t ocores_isr(int irq, void *dev_id, struct pt_regs *regs)
 {
 	struct ocores_i2c *i2c = dev_id;

 	ocores_process(i2c);

 	return IRQ_HANDLED;
 }

 static int ocores_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
 {
 	struct ocores_i2c *i2c = i2c_get_adapdata(adap);

 	i2c->msg = msgs;
 	i2c->pos = 0;
 	i2c->nmsgs = num;
 	i2c->state = STATE_START;

 	oc_setreg(i2c, OCI2C_DATA,
 			(i2c->msg->addr << 1) |
 			((i2c->msg->flags & I2C_M_RD) ? 1:0));

 	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_START);

 	if (wait_event_timeout(i2c->wait, (i2c->state == STATE_ERROR) ||
 			       (i2c->state == STATE_DONE), HZ))
 		return (i2c->state == STATE_DONE) ? num : -EIO;
 	else
 		return -ETIMEDOUT;
 }

 static void ocores_init(struct ocores_i2c *i2c,
 			struct ocores_i2c_platform_data *pdata)
 {
 	int prescale;
 	u8 ctrl = oc_getreg(i2c, OCI2C_CONTROL);

 	/* make sure the device is disabled */
 	oc_setreg(i2c, OCI2C_CONTROL, ctrl & ~(OCI2C_CTRL_EN|OCI2C_CTRL_IEN));

 	prescale = (pdata->clock_khz / (5*100)) - 1;
 	oc_setreg(i2c, OCI2C_PRELOW, prescale & 0xff);
 	oc_setreg(i2c, OCI2C_PREHIGH, prescale >> 8);

 	/* Init the device */
 	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK);
 	oc_setreg(i2c, OCI2C_CONTROL, ctrl | OCI2C_CTRL_IEN | OCI2C_CTRL_EN);
 }


 static u32 ocores_func(struct i2c_adapter *adap)
 {
 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 }

 static const struct i2c_algorithm ocores_algorithm = {
 	.master_xfer	= ocores_xfer,
 	.functionality	= ocores_func,
 };

 static struct i2c_adapter ocores_adapter = {
 	.owner		= THIS_MODULE,
 	.name		= "i2c-ocores",
 	.class		= I2C_CLASS_HWMON,
 	.algo		= &ocores_algorithm,
 };


 static int __devinit ocores_i2c_probe(struct platform_device *pdev)
 {
 	struct ocores_i2c *i2c;
 	struct ocores_i2c_platform_data *pdata;
 	struct resource *res, *res2;
 	int ret;

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!res)
 		return -ENODEV;

 	res2 = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 	if (!res2)
 		return -ENODEV;

 	pdata = (struct ocores_i2c_platform_data*) pdev->dev.platform_data;
 	if (!pdata)
 		return -ENODEV;

 	i2c = kzalloc(sizeof(*i2c), GFP_KERNEL);
 	if (!i2c)
 		return -ENOMEM;

 	if (!request_mem_region(res->start, res->end - res->start + 1,
 				pdev->name)) {
 		dev_err(&pdev->dev, "Memory region busy\n");
 		ret = -EBUSY;
 		goto request_mem_failed;
 	}

 	i2c->base = ioremap(res->start, res->end - res->start + 1);
 	if (!i2c->base) {
 		dev_err(&pdev->dev, "Unable to map registers\n");
 		ret = -EIO;
 		goto map_failed;
 	}

 	i2c->regstep = pdata->regstep;
 	ocores_init(i2c, pdata);

 	init_waitqueue_head(&i2c->wait);
 	ret = request_irq(res2->start, ocores_isr, 0, pdev->name, i2c);
 	if (ret) {
 		dev_err(&pdev->dev, "Cannot claim IRQ\n");
 		goto request_irq_failed;
 	}

 	/* hook up driver to tree */
 	platform_set_drvdata(pdev, i2c);
 	i2c->adap = ocores_adapter;
 	i2c_set_adapdata(&i2c->adap, i2c);
 	i2c->adap.dev.parent = &pdev->dev;

 	/* add i2c adapter to i2c tree */
 	ret = i2c_add_adapter(&i2c->adap);
 	if (ret) {
 		dev_err(&pdev->dev, "Failed to add adapter\n");
 		goto add_adapter_failed;
 	}

 	return 0;

 add_adapter_failed:
 	free_irq(res2->start, i2c);
 request_irq_failed:
 	iounmap(i2c->base);
 map_failed:
 	release_mem_region(res->start, res->end - res->start + 1);
 request_mem_failed:
 	kfree(i2c);

 	return ret;
 }

 static int __devexit ocores_i2c_remove(struct platform_device* pdev)
 {
 	struct ocores_i2c *i2c = platform_get_drvdata(pdev);
 	struct resource *res;

 	/* disable i2c logic */
 	oc_setreg(i2c, OCI2C_CONTROL, oc_getreg(i2c, OCI2C_CONTROL)
 		  & ~(OCI2C_CTRL_EN|OCI2C_CTRL_IEN));

 	/* remove adapter & data */
 	i2c_del_adapter(&i2c->adap);
 	platform_set_drvdata(pdev, NULL);

 	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 	if (res)
 		free_irq(res->start, i2c);

 	iounmap(i2c->base);

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (res)
 		release_mem_region(res->start, res->end - res->start + 1);

 	kfree(i2c);

 	return 0;
 }

 static struct platform_driver ocores_i2c_driver = {
 	.probe  = ocores_i2c_probe,
 	.remove = __devexit_p(ocores_i2c_remove),
 	.driver = {
 		.owner = THIS_MODULE,
 		.name = "ocores-i2c",
 	},
 };

 static int __init ocores_i2c_init(void)
 {
 	return platform_driver_register(&ocores_i2c_driver);
 }

 static void __exit ocores_i2c_exit(void)
 {
 	platform_driver_unregister(&ocores_i2c_driver);
 }

 module_init(ocores_i2c_init);
 module_exit(ocores_i2c_exit);

 MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>");
 MODULE_DESCRIPTION("OpenCores I2C bus driver");
 MODULE_LICENSE("GPL");
	/*
	* i2c-ocores.c: I2C bus driver for OpenCores I2C controller
	* (http://www.opencores.org/projects.cgi/web/i2c/overview).
	*
	* Peter Korsgaard <jacmet@sunsite.dk>
	*
	* This file is licensed under the terms of the GNU General Public License
	* version 2. This program is licensed "as is" without any warranty of any
	* kind, whether express or implied.
	*/

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/sched.h>
	#include <linux/init.h>
	#include <linux/errno.h>
	#include <linux/platform_device.h>
	#include <linux/i2c.h>
	#include <linux/interrupt.h>
	#include <linux/wait.h>
	#include <linux/i2c-ocores.h>
	#include <asm/io.h>

	struct ocores_i2c {
	void __iomem *base;
	int regstep;
	wait_queue_head_t wait;
	struct i2c_adapter adap;
	struct i2c_msg *msg;
	int pos;
	int nmsgs;
	int state; /* see STATE_ */
	};

	/* registers */
	#define OCI2C_PRELOW 0
	#define OCI2C_PREHIGH 1
	#define OCI2C_CONTROL 2
	#define OCI2C_DATA 3
	#define OCI2C_CMD 4 /* write only */
	#define OCI2C_STATUS 4 /* read only, same address as OCI2C_CMD */

	#define OCI2C_CTRL_IEN 0x40
	#define OCI2C_CTRL_EN 0x80

	#define OCI2C_CMD_START 0x91
	#define OCI2C_CMD_STOP 0x41
	#define OCI2C_CMD_READ 0x21
	#define OCI2C_CMD_WRITE 0x11
	#define OCI2C_CMD_READ_ACK 0x21
	#define OCI2C_CMD_READ_NACK 0x29
	#define OCI2C_CMD_IACK 0x01

	#define OCI2C_STAT_IF 0x01
	#define OCI2C_STAT_TIP 0x02
	#define OCI2C_STAT_ARBLOST 0x20
	#define OCI2C_STAT_BUSY 0x40
	#define OCI2C_STAT_NACK 0x80

	#define STATE_DONE 0
	#define STATE_START 1
	#define STATE_WRITE 2
	#define STATE_READ 3
	#define STATE_ERROR 4

	static inline void oc_setreg(struct ocores_i2c *i2c, int reg, u8 value)
	{
	iowrite8(value, i2c->base + reg * i2c->regstep);
	}

	static inline u8 oc_getreg(struct ocores_i2c *i2c, int reg)
	{
	return ioread8(i2c->base + reg * i2c->regstep);
	}

	static void ocores_process(struct ocores_i2c *i2c)
	{
	struct i2c_msg *msg = i2c->msg;
	u8 stat = oc_getreg(i2c, OCI2C_STATUS);

	if ((i2c->state == STATE_DONE) \|\| (i2c->state == STATE_ERROR)) {
	/* stop has been sent */
	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK);
	wake_up(&i2c->wait);
	return;
	}

	/* error? */
	if (stat & OCI2C_STAT_ARBLOST) {
	i2c->state = STATE_ERROR;
	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
	return;
	}

	if ((i2c->state == STATE_START) \|\| (i2c->state == STATE_WRITE)) {
	i2c->state =
	(msg->flags & I2C_M_RD) ? STATE_READ : STATE_WRITE;

	if (stat & OCI2C_STAT_NACK) {
	i2c->state = STATE_ERROR;
	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
	return;
	}
	} else
	msg->buf[i2c->pos++] = oc_getreg(i2c, OCI2C_DATA);

	/* end of msg? */
	if (i2c->pos == msg->len) {
	i2c->nmsgs--;
	i2c->msg++;
	i2c->pos = 0;
	msg = i2c->msg;

	if (i2c->nmsgs) { /* end? */
	/* send start? */
	if (!(msg->flags & I2C_M_NOSTART)) {
	u8 addr = (msg->addr << 1);

	if (msg->flags & I2C_M_RD)
	addr \|= 1;

	i2c->state = STATE_START;

	oc_setreg(i2c, OCI2C_DATA, addr);
	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_START);
	return;
	} else
	i2c->state = (msg->flags & I2C_M_RD)
	? STATE_READ : STATE_WRITE;
	} else {
	i2c->state = STATE_DONE;
	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
	return;
	}
	}

	if (i2c->state == STATE_READ) {
	oc_setreg(i2c, OCI2C_CMD, i2c->pos == (msg->len-1) ?
	OCI2C_CMD_READ_NACK : OCI2C_CMD_READ_ACK);
	} else {
	oc_setreg(i2c, OCI2C_DATA, msg->buf[i2c->pos++]);
	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_WRITE);
	}
	}

	static irqreturn_t ocores_isr(int irq, void dev_id, struct pt_regs regs)
	{
	struct ocores_i2c *i2c = dev_id;

	ocores_process(i2c);

	return IRQ_HANDLED;
	}

	static int ocores_xfer(struct i2c_adapter adap, struct i2c_msg msgs, int num)
	{
	struct ocores_i2c *i2c = i2c_get_adapdata(adap);

	i2c->msg = msgs;
	i2c->pos = 0;
	i2c->nmsgs = num;
	i2c->state = STATE_START;

	oc_setreg(i2c, OCI2C_DATA,
	(i2c->msg->addr << 1) \|
	((i2c->msg->flags & I2C_M_RD) ? 1:0));

	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_START);

	if (wait_event_timeout(i2c->wait, (i2c->state == STATE_ERROR) \|\|
	(i2c->state == STATE_DONE), HZ))
	return (i2c->state == STATE_DONE) ? num : -EIO;
	else
	return -ETIMEDOUT;
	}

	static void ocores_init(struct ocores_i2c *i2c,
	struct ocores_i2c_platform_data *pdata)
	{
	int prescale;
	u8 ctrl = oc_getreg(i2c, OCI2C_CONTROL);

	/* make sure the device is disabled */
	oc_setreg(i2c, OCI2C_CONTROL, ctrl & ~(OCI2C_CTRL_EN\|OCI2C_CTRL_IEN));

	prescale = (pdata->clock_khz / (5*100)) - 1;
	oc_setreg(i2c, OCI2C_PRELOW, prescale & 0xff);
	oc_setreg(i2c, OCI2C_PREHIGH, prescale >> 8);

	/* Init the device */
	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK);
	oc_setreg(i2c, OCI2C_CONTROL, ctrl \| OCI2C_CTRL_IEN \| OCI2C_CTRL_EN);
	}


	static u32 ocores_func(struct i2c_adapter *adap)
	{
	return I2C_FUNC_I2C \| I2C_FUNC_SMBUS_EMUL;
	}

	static const struct i2c_algorithm ocores_algorithm = {
	.master_xfer = ocores_xfer,
	.functionality = ocores_func,
	};

	static struct i2c_adapter ocores_adapter = {
	.owner = THIS_MODULE,
	.name = "i2c-ocores",
	.class = I2C_CLASS_HWMON,
	.algo = &ocores_algorithm,
	};


	static int __devinit ocores_i2c_probe(struct platform_device *pdev)
	{
	struct ocores_i2c *i2c;
	struct ocores_i2c_platform_data *pdata;
	struct resource res, res2;
	int ret;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res)
	return -ENODEV;

	res2 = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
	if (!res2)
	return -ENODEV;

	pdata = (struct ocores_i2c_platform_data*) pdev->dev.platform_data;
	if (!pdata)
	return -ENODEV;

	i2c = kzalloc(sizeof(*i2c), GFP_KERNEL);
	if (!i2c)
	return -ENOMEM;

	if (!request_mem_region(res->start, res->end - res->start + 1,
	pdev->name)) {
	dev_err(&pdev->dev, "Memory region busy\n");
	ret = -EBUSY;
	goto request_mem_failed;
	}

	i2c->base = ioremap(res->start, res->end - res->start + 1);
	if (!i2c->base) {
	dev_err(&pdev->dev, "Unable to map registers\n");
	ret = -EIO;
	goto map_failed;
	}

	i2c->regstep = pdata->regstep;
	ocores_init(i2c, pdata);

	init_waitqueue_head(&i2c->wait);
	ret = request_irq(res2->start, ocores_isr, 0, pdev->name, i2c);
	if (ret) {
	dev_err(&pdev->dev, "Cannot claim IRQ\n");
	goto request_irq_failed;
	}

	/* hook up driver to tree */
	platform_set_drvdata(pdev, i2c);
	i2c->adap = ocores_adapter;
	i2c_set_adapdata(&i2c->adap, i2c);
	i2c->adap.dev.parent = &pdev->dev;

	/* add i2c adapter to i2c tree */
	ret = i2c_add_adapter(&i2c->adap);
	if (ret) {
	dev_err(&pdev->dev, "Failed to add adapter\n");
	goto add_adapter_failed;
	}

	return 0;

	add_adapter_failed:
	free_irq(res2->start, i2c);
	request_irq_failed:
	iounmap(i2c->base);
	map_failed:
	release_mem_region(res->start, res->end - res->start + 1);
	request_mem_failed:
	kfree(i2c);

	return ret;
	}

	static int __devexit ocores_i2c_remove(struct platform_device* pdev)
	{
	struct ocores_i2c *i2c = platform_get_drvdata(pdev);
	struct resource *res;

	/* disable i2c logic */
	oc_setreg(i2c, OCI2C_CONTROL, oc_getreg(i2c, OCI2C_CONTROL)
	& ~(OCI2C_CTRL_EN\|OCI2C_CTRL_IEN));

	/* remove adapter & data */
	i2c_del_adapter(&i2c->adap);
	platform_set_drvdata(pdev, NULL);

	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
	if (res)
	free_irq(res->start, i2c);

	iounmap(i2c->base);

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (res)
	release_mem_region(res->start, res->end - res->start + 1);

	kfree(i2c);

	return 0;
	}

	static struct platform_driver ocores_i2c_driver = {
	.probe = ocores_i2c_probe,
	.remove = __devexit_p(ocores_i2c_remove),
	.driver = {
	.owner = THIS_MODULE,
	.name = "ocores-i2c",
	},
	};

	static int __init ocores_i2c_init(void)
	{
	return platform_driver_register(&ocores_i2c_driver);
	}

	static void __exit ocores_i2c_exit(void)
	{
	platform_driver_unregister(&ocores_i2c_driver);
	}

	module_init(ocores_i2c_init);
	module_exit(ocores_i2c_exit);

	MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>");
	MODULE_DESCRIPTION("OpenCores I2C bus driver");
	MODULE_LICENSE("GPL");