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Commit da672773 authored by Magnus Damm's avatar Magnus Damm Committed by Jean Delvare
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i2c: New driver for the SuperH Mobile I2C bus controller 



This is V5 of the SuperH Mobile I2C Controller Driver. A simple Master
only driver for the I2C block included in processors such as sh7343,
sh7722 and sh7723. Tested on a sh7722 MigoR using a rs5c732b rtc.

Signed-off-by: default avatarMagnus Damm <damm@igel.co.jp>
Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
Signed-off-by: default avatarJean Delvare <khali@linux-fr.org>
parent dec1a998

drivers/i2c/busses/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -695,4 +695,14 @@ config I2C_SH7760 
	  This driver can also be built as a module.  If so, the module

	  will be called i2c-sh7760.



config I2C_SH_MOBILE

	tristate "SuperH Mobile I2C Controller"

	depends on SUPERH

	help

	  If you say yes to this option, support will be included for the

	  built-in I2C interface on the Renesas SH-Mobile processor.



	  This driver can also be built as a module.  If so, the module

	  will be called i2c-sh_mobile.



endmenu

drivers/i2c/busses/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -39,6 +39,7 @@ obj-$(CONFIG_I2C_PXA) += i2c-pxa.o 
obj-$(CONFIG_I2C_S3C2410)	+= i2c-s3c2410.o

obj-$(CONFIG_I2C_SAVAGE4)	+= i2c-savage4.o

obj-$(CONFIG_I2C_SH7760)	+= i2c-sh7760.o

obj-$(CONFIG_I2C_SH_MOBILE)	+= i2c-sh_mobile.o

obj-$(CONFIG_I2C_SIBYTE)	+= i2c-sibyte.o

obj-$(CONFIG_I2C_SIMTEC)	+= i2c-simtec.o

obj-$(CONFIG_I2C_SIS5595)	+= i2c-sis5595.o

drivers/i2c/busses/i2c-sh_mobile.c

0 → 100644
+500 −0
Original line number Diff line number Diff line 
/*

 * SuperH Mobile I2C Controller

 *

 * Copyright (C) 2008 Magnus Damm

 *

 * Portions of the code based on out-of-tree driver i2c-sh7343.c

 * Copyright (c) 2006 Carlos Munoz <carlos@kenati.com>

 *

 * 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

 *

 * 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/kernel.h>

#include <linux/module.h>

#include <linux/init.h>

#include <linux/delay.h>

#include <linux/platform_device.h>

#include <linux/interrupt.h>

#include <linux/i2c.h>

#include <linux/err.h>

#include <linux/clk.h>

#include <linux/io.h>



enum sh_mobile_i2c_op {

	OP_START = 0,

	OP_TX_ONLY,

	OP_TX_STOP,

	OP_TX_TO_RX,

	OP_RX_ONLY,

	OP_RX_STOP,

};



struct sh_mobile_i2c_data {

	struct device *dev;

	void __iomem *reg;

	struct i2c_adapter adap;



	struct clk *clk;

	u_int8_t iccl;

	u_int8_t icch;



	spinlock_t lock;

	wait_queue_head_t wait;

	struct i2c_msg *msg;

	int pos;

	int sr;

};



#define NORMAL_SPEED		100000 /* FAST_SPEED 400000 */



/* Register offsets */

#define ICDR(pd)		(pd->reg + 0x00)

#define ICCR(pd)		(pd->reg + 0x04)

#define ICSR(pd)		(pd->reg + 0x08)

#define ICIC(pd)		(pd->reg + 0x0c)

#define ICCL(pd)		(pd->reg + 0x10)

#define ICCH(pd)		(pd->reg + 0x14)



/* Register bits */

#define ICCR_ICE		0x80

#define ICCR_RACK		0x40

#define ICCR_TRS		0x10

#define ICCR_BBSY		0x04

#define ICCR_SCP		0x01



#define ICSR_SCLM		0x80

#define ICSR_SDAM		0x40

#define SW_DONE			0x20

#define ICSR_BUSY		0x10

#define ICSR_AL			0x08

#define ICSR_TACK		0x04

#define ICSR_WAIT		0x02

#define ICSR_DTE		0x01



#define ICIC_ALE		0x08

#define ICIC_TACKE		0x04

#define ICIC_WAITE		0x02

#define ICIC_DTEE		0x01



static void activate_ch(struct sh_mobile_i2c_data *pd)

{

	/* Make sure the clock is enabled */

	clk_enable(pd->clk);



	/* Enable channel and configure rx ack */

	iowrite8(ioread8(ICCR(pd)) | ICCR_ICE, ICCR(pd));



	/* Mask all interrupts */

	iowrite8(0, ICIC(pd));



	/* Set the clock */

	iowrite8(pd->iccl, ICCL(pd));

	iowrite8(pd->icch, ICCH(pd));

}



static void deactivate_ch(struct sh_mobile_i2c_data *pd)

{

	/* Clear/disable interrupts */

	iowrite8(0, ICSR(pd));

	iowrite8(0, ICIC(pd));



	/* Disable channel */

	iowrite8(ioread8(ICCR(pd)) & ~ICCR_ICE, ICCR(pd));



	/* Disable clock */

	clk_disable(pd->clk);

}



static unsigned char i2c_op(struct sh_mobile_i2c_data *pd,

			    enum sh_mobile_i2c_op op, unsigned char data)

{

	unsigned char ret = 0;

	unsigned long flags;



	dev_dbg(pd->dev, "op %d, data in 0x%02x\n", op, data);



	spin_lock_irqsave(&pd->lock, flags);



	switch (op) {

	case OP_START:

		iowrite8(0x94, ICCR(pd));

		break;

	case OP_TX_ONLY:

		iowrite8(data, ICDR(pd));

		break;

	case OP_TX_STOP:

		iowrite8(data, ICDR(pd));

		iowrite8(0x90, ICCR(pd));

		iowrite8(ICIC_ALE | ICIC_TACKE, ICIC(pd));

		break;

	case OP_TX_TO_RX:

		iowrite8(data, ICDR(pd));

		iowrite8(0x81, ICCR(pd));

		break;

	case OP_RX_ONLY:

		ret = ioread8(ICDR(pd));

		break;

	case OP_RX_STOP:

		ret = ioread8(ICDR(pd));

		iowrite8(0xc0, ICCR(pd));

		break;

	}



	spin_unlock_irqrestore(&pd->lock, flags);



	dev_dbg(pd->dev, "op %d, data out 0x%02x\n", op, ret);

	return ret;

}



static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)

{

	struct platform_device *dev = dev_id;

	struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);

	struct i2c_msg *msg = pd->msg;

	unsigned char data, sr;

	int wakeup = 0;



	sr = ioread8(ICSR(pd));

	pd->sr |= sr;



	dev_dbg(pd->dev, "i2c_isr 0x%02x 0x%02x %s %d %d!\n", sr, pd->sr,

	       (msg->flags & I2C_M_RD) ? "read" : "write",

	       pd->pos, msg->len);



	if (sr & (ICSR_AL | ICSR_TACK)) {

		iowrite8(0, ICIC(pd)); /* disable interrupts */

		wakeup = 1;

		goto do_wakeup;

	}



	if (pd->pos == msg->len) {

		i2c_op(pd, OP_RX_ONLY, 0);

		wakeup = 1;

		goto do_wakeup;

	}



	if (pd->pos == -1) {

		data = (msg->addr & 0x7f) << 1;

		data |= (msg->flags & I2C_M_RD) ? 1 : 0;

	} else

		data = msg->buf[pd->pos];



	if ((pd->pos == -1) || !(msg->flags & I2C_M_RD)) {

		if (msg->flags & I2C_M_RD)

			i2c_op(pd, OP_TX_TO_RX, data);

		else if (pd->pos == (msg->len - 1)) {

			i2c_op(pd, OP_TX_STOP, data);

			wakeup = 1;

		} else

			i2c_op(pd, OP_TX_ONLY, data);

	} else {

		if (pd->pos == (msg->len - 1))

			data = i2c_op(pd, OP_RX_STOP, 0);

		else

			data = i2c_op(pd, OP_RX_ONLY, 0);



		msg->buf[pd->pos] = data;

	}

	pd->pos++;



 do_wakeup:

	if (wakeup) {

		pd->sr |= SW_DONE;

		wake_up(&pd->wait);

	}



	return IRQ_HANDLED;

}



static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg)

{

	/* Initialize channel registers */

	iowrite8(ioread8(ICCR(pd)) & ~ICCR_ICE, ICCR(pd));



	/* Enable channel and configure rx ack */

	iowrite8(ioread8(ICCR(pd)) | ICCR_ICE, ICCR(pd));



	/* Set the clock */

	iowrite8(pd->iccl, ICCL(pd));

	iowrite8(pd->icch, ICCH(pd));



	pd->msg = usr_msg;

	pd->pos = -1;

	pd->sr = 0;



	/* Enable all interrupts except wait */

	iowrite8(ioread8(ICIC(pd)) | ICIC_ALE | ICIC_TACKE | ICIC_DTEE,

		 ICIC(pd));

	return 0;

}



static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,

			      struct i2c_msg *msgs,

			      int num)

{

	struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adapter);

	struct i2c_msg	*msg;

	int err = 0;

	u_int8_t val;

	int i, k, retry_count;



	activate_ch(pd);



	/* Process all messages */

	for (i = 0; i < num; i++) {

		msg = &msgs[i];



		err = start_ch(pd, msg);

		if (err)

			break;



		i2c_op(pd, OP_START, 0);



		/* The interrupt handler takes care of the rest... */

		k = wait_event_timeout(pd->wait,

				       pd->sr & (ICSR_TACK | SW_DONE),

				       5 * HZ);

		if (!k)

			dev_err(pd->dev, "Transfer request timed out\n");



		retry_count = 10;

again:

		val = ioread8(ICSR(pd));



		dev_dbg(pd->dev, "val 0x%02x pd->sr 0x%02x\n", val, pd->sr);



		if ((val | pd->sr) & (ICSR_TACK | ICSR_AL)) {

			err = -EIO;

			break;

		}



		/* the interrupt handler may wake us up before the

		 * transfer is finished, so poll the hardware

		 * until we're done.

		 */



		if (!(!(val & ICSR_BUSY) && (val & ICSR_SCLM) &&

		      (val & ICSR_SDAM))) {

			msleep(1);

			if (retry_count--)

				goto again;



			err = -EIO;

			dev_err(pd->dev, "Polling timed out\n");

			break;

		}

	}



	deactivate_ch(pd);



	if (!err)

		err = num;

	return err;

}



static u32 sh_mobile_i2c_func(struct i2c_adapter *adapter)

{

	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;

}



static struct i2c_algorithm sh_mobile_i2c_algorithm = {

	.functionality	= sh_mobile_i2c_func,

	.master_xfer	= sh_mobile_i2c_xfer,

};



static void sh_mobile_i2c_setup_channel(struct platform_device *dev)

{

	struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);

	unsigned long peripheral_clk = clk_get_rate(pd->clk);

	u_int32_t num;

	u_int32_t denom;

	u_int32_t tmp;



	spin_lock_init(&pd->lock);

	init_waitqueue_head(&pd->wait);



	/* Calculate the value for iccl. From the data sheet:

	 * iccl = (p clock / transfer rate) * (L / (L + H))

	 * where L and H are the SCL low/high ratio (5/4 in this case).

	 * We also round off the result.

	 */

	num = peripheral_clk * 5;

	denom = NORMAL_SPEED * 9;

	tmp = num * 10 / denom;

	if (tmp % 10 >= 5)

		pd->iccl = (u_int8_t)((num/denom) + 1);

	else

		pd->iccl = (u_int8_t)(num/denom);



	/* Calculate the value for icch. From the data sheet:

	   icch = (p clock / transfer rate) * (H / (L + H)) */

	num = peripheral_clk * 4;

	tmp = num * 10 / denom;

	if (tmp % 10 >= 5)

		pd->icch = (u_int8_t)((num/denom) + 1);

	else

		pd->icch = (u_int8_t)(num/denom);

}



static int sh_mobile_i2c_hook_irqs(struct platform_device *dev, int hook)

{

	struct resource *res;

	int ret = -ENXIO;

	int q, m;

	int k = 0;

	int n = 0;



	while ((res = platform_get_resource(dev, IORESOURCE_IRQ, k))) {

		for (n = res->start; hook && n <= res->end; n++) {

			if (request_irq(n, sh_mobile_i2c_isr, IRQF_DISABLED,

					dev->dev.bus_id, dev))

				goto rollback;

		}

		k++;

	}



	if (hook)

		return k > 0 ? 0 : -ENOENT;



	k--;

	ret = 0;



 rollback:

	for (q = k; k >= 0; k--) {

		for (m = n; m >= res->start; m--)

			free_irq(m, dev);



		res = platform_get_resource(dev, IORESOURCE_IRQ, k - 1);

		m = res->end;

	}



	return ret;

}



static int sh_mobile_i2c_probe(struct platform_device *dev)

{

	struct sh_mobile_i2c_data *pd;

	struct i2c_adapter *adap;

	struct resource *res;

	int size;

	int ret;



	pd = kzalloc(sizeof(struct sh_mobile_i2c_data), GFP_KERNEL);

	if (pd == NULL) {

		dev_err(&dev->dev, "cannot allocate private data\n");

		return -ENOMEM;

	}



	pd->clk = clk_get(&dev->dev, "peripheral_clk");

	if (IS_ERR(pd->clk)) {

		dev_err(&dev->dev, "cannot get peripheral clock\n");

		ret = PTR_ERR(pd->clk);

		goto err;

	}



	ret = sh_mobile_i2c_hook_irqs(dev, 1);

	if (ret) {

		dev_err(&dev->dev, "cannot request IRQ\n");

		goto err_clk;

	}



	pd->dev = &dev->dev;

	platform_set_drvdata(dev, pd);



	res = platform_get_resource(dev, IORESOURCE_MEM, 0);

	if (res == NULL) {

		dev_err(&dev->dev, "cannot find IO resource\n");

		ret = -ENOENT;

		goto err_irq;

	}



	size = (res->end - res->start) + 1;



	pd->reg = ioremap(res->start, size);

	if (pd->reg == NULL) {

		dev_err(&dev->dev, "cannot map IO\n");

		ret = -ENXIO;

		goto err_irq;

	}



	/* setup the private data */

	adap = &pd->adap;

	i2c_set_adapdata(adap, pd);



	adap->owner = THIS_MODULE;

	adap->algo = &sh_mobile_i2c_algorithm;

	adap->dev.parent = &dev->dev;

	adap->retries = 5;

	adap->nr = dev->id;



	strlcpy(adap->name, dev->name, sizeof(adap->name));



	sh_mobile_i2c_setup_channel(dev);



	ret = i2c_add_numbered_adapter(adap);

	if (ret < 0) {

		dev_err(&dev->dev, "cannot add numbered adapter\n");

		goto err_all;

	}



	return 0;



 err_all:

	iounmap(pd->reg);

 err_irq:

	sh_mobile_i2c_hook_irqs(dev, 0);

 err_clk:

	clk_put(pd->clk);

 err:

	kfree(pd);

	return ret;

}



static int sh_mobile_i2c_remove(struct platform_device *dev)

{

	struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);



	i2c_del_adapter(&pd->adap);

	iounmap(pd->reg);

	sh_mobile_i2c_hook_irqs(dev, 0);

	clk_put(pd->clk);

	kfree(pd);

	return 0;

}



static struct platform_driver sh_mobile_i2c_driver = {

	.driver		= {

		.name		= "i2c-sh_mobile",

		.owner		= THIS_MODULE,

	},

	.probe		= sh_mobile_i2c_probe,

	.remove		= sh_mobile_i2c_remove,

};



static int __init sh_mobile_i2c_adap_init(void)

{

	return platform_driver_register(&sh_mobile_i2c_driver);

}



static void __exit sh_mobile_i2c_adap_exit(void)

{

	platform_driver_unregister(&sh_mobile_i2c_driver);

}



module_init(sh_mobile_i2c_adap_init);

module_exit(sh_mobile_i2c_adap_exit);



MODULE_DESCRIPTION("SuperH Mobile I2C Bus Controller driver");

MODULE_AUTHOR("Magnus Damm");

MODULE_LICENSE("GPL v2");