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Commit b486ddbc authored by Oskar Schirmer's avatar Oskar Schirmer Committed by Ben Dooks
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i2c: xtensa s6000 i2c driver 



Support for the s6000 on-chip i2c controller.

Signed-off-by: default avatarOskar Schirmer <os@emlix.com>
Signed-off-by: default avatarDaniel Glöckner <dg@emlix.com>
Signed-off-by: default avatarBen Dooks <ben-linux@fluff.org>
parent c724d67d

drivers/i2c/busses/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -472,6 +472,16 @@ config I2C_S3C2410 
	  Say Y here to include support for I2C controller in the

	  Samsung S3C2410 based System-on-Chip devices.



config I2C_S6000

	tristate "S6000 I2C support"

	depends on XTENSA_VARIANT_S6000

	help

	  This driver supports the on chip I2C device on the

	  S6000 xtensa processor family.



	  To compile this driver as a module, choose M here. The module

	  will be called i2c-s6000.



config I2C_SH7760

	tristate "Renesas SH7760 I2C Controller"

	depends on CPU_SUBTYPE_SH7760

drivers/i2c/busses/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -44,6 +44,7 @@ obj-$(CONFIG_I2C_PASEMI) += i2c-pasemi.o 
obj-$(CONFIG_I2C_PNX)		+= i2c-pnx.o

obj-$(CONFIG_I2C_PXA)		+= i2c-pxa.o

obj-$(CONFIG_I2C_S3C2410)	+= i2c-s3c2410.o

obj-$(CONFIG_I2C_S6000)		+= i2c-s6000.o

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

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

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

drivers/i2c/busses/i2c-s6000.c

0 → 100644
+407 −0
Original line number Diff line number Diff line 
/*

 * drivers/i2c/busses/i2c-s6000.c

 *

 * Description: Driver for S6000 Family I2C Interface

 * Copyright (c) 2008 emlix GmbH

 * Author:	Oskar Schirmer <os@emlix.com>

 *

 * Partially based on i2c-bfin-twi.c driver by <sonic.zhang@analog.com>

 * Copyright (c) 2005-2007 Analog Devices, Inc.

 *

 * 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., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA

 */



#include <linux/clk.h>

#include <linux/err.h>

#include <linux/module.h>

#include <linux/kernel.h>

#include <linux/init.h>

#include <linux/delay.h>

#include <linux/i2c.h>

#include <linux/i2c/s6000.h>

#include <linux/timer.h>

#include <linux/spinlock.h>

#include <linux/completion.h>

#include <linux/interrupt.h>

#include <linux/platform_device.h>



#include <asm/io.h>

#include "i2c-s6000.h"



#define DRV_NAME "i2c-s6000"



#define POLL_TIMEOUT	(2 * HZ)



struct s6i2c_if {

	u8 __iomem		*reg; /* memory mapped registers */

	int			irq;

	spinlock_t		lock;

	struct i2c_msg		*msgs; /* messages currently handled */

	int			msgs_num; /* nb of msgs to do */

	int			msgs_push; /* nb of msgs read/written */

	int			msgs_done; /* nb of msgs finally handled */

	unsigned		push; /* nb of bytes read/written in msg */

	unsigned		done; /* nb of bytes finally handled */

	int			timeout_count; /* timeout retries left */

	struct timer_list	timeout_timer;

	struct i2c_adapter	adap;

	struct completion	complete;

	struct clk		*clk;

	struct resource		*res;

};



static inline u16 i2c_rd16(struct s6i2c_if *iface, unsigned n)

{

	return readw(iface->reg + (n));

}



static inline void i2c_wr16(struct s6i2c_if *iface, unsigned n, u16 v)

{

	writew(v, iface->reg + (n));

}



static inline u32 i2c_rd32(struct s6i2c_if *iface, unsigned n)

{

	return readl(iface->reg + (n));

}



static inline void i2c_wr32(struct s6i2c_if *iface, unsigned n, u32 v)

{

	writel(v, iface->reg + (n));

}



static struct s6i2c_if s6i2c_if;



static void s6i2c_handle_interrupt(struct s6i2c_if *iface)

{

	if (i2c_rd16(iface, S6_I2C_INTRSTAT) & (1 << S6_I2C_INTR_TXABRT)) {

		i2c_rd16(iface, S6_I2C_CLRTXABRT);

		i2c_wr16(iface, S6_I2C_INTRMASK, 0);

		complete(&iface->complete);

		return;

	}

	if (iface->msgs_done >= iface->msgs_num) {

		dev_err(&iface->adap.dev, "s6i2c: spurious I2C irq: %04x\n",

			i2c_rd16(iface, S6_I2C_INTRSTAT));

		i2c_wr16(iface, S6_I2C_INTRMASK, 0);

		return;

	}

	while ((iface->msgs_push < iface->msgs_num)

	    && (i2c_rd16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_TFNF))) {

		struct i2c_msg *m = &iface->msgs[iface->msgs_push];

		if (!(m->flags & I2C_M_RD))

			i2c_wr16(iface, S6_I2C_DATACMD, m->buf[iface->push]);

		else

			i2c_wr16(iface, S6_I2C_DATACMD,

				 1 << S6_I2C_DATACMD_READ);

		if (++iface->push >= m->len) {

			iface->push = 0;

			iface->msgs_push += 1;

		}

	}

	do {

		struct i2c_msg *m = &iface->msgs[iface->msgs_done];

		if (!(m->flags & I2C_M_RD)) {

			if (iface->msgs_done < iface->msgs_push)

				iface->msgs_done += 1;

			else

				break;

		} else if (i2c_rd16(iface, S6_I2C_STATUS)

				& (1 << S6_I2C_STATUS_RFNE)) {

			m->buf[iface->done] = i2c_rd16(iface, S6_I2C_DATACMD);

			if (++iface->done >= m->len) {

				iface->done = 0;

				iface->msgs_done += 1;

			}

		} else{

			break;

		}

	} while (iface->msgs_done < iface->msgs_num);

	if (iface->msgs_done >= iface->msgs_num) {

		i2c_wr16(iface, S6_I2C_INTRMASK, 1 << S6_I2C_INTR_TXABRT);

		complete(&iface->complete);

	} else if (iface->msgs_push >= iface->msgs_num) {

		i2c_wr16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXABRT) |

						 (1 << S6_I2C_INTR_RXFULL));

	} else {

		i2c_wr16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXABRT) |

						 (1 << S6_I2C_INTR_TXEMPTY) |

						 (1 << S6_I2C_INTR_RXFULL));

	}

}



static irqreturn_t s6i2c_interrupt_entry(int irq, void *dev_id)

{

	struct s6i2c_if *iface = dev_id;

	if (!(i2c_rd16(iface, S6_I2C_STATUS) & ((1 << S6_I2C_INTR_RXUNDER)

					      | (1 << S6_I2C_INTR_RXOVER)

					      | (1 << S6_I2C_INTR_RXFULL)

					      | (1 << S6_I2C_INTR_TXOVER)

					      | (1 << S6_I2C_INTR_TXEMPTY)

					      | (1 << S6_I2C_INTR_RDREQ)

					      | (1 << S6_I2C_INTR_TXABRT)

					      | (1 << S6_I2C_INTR_RXDONE)

					      | (1 << S6_I2C_INTR_ACTIVITY)

					      | (1 << S6_I2C_INTR_STOPDET)

					      | (1 << S6_I2C_INTR_STARTDET)

					      | (1 << S6_I2C_INTR_GENCALL))))

		return IRQ_NONE;



	spin_lock(&iface->lock);

	del_timer(&iface->timeout_timer);

	s6i2c_handle_interrupt(iface);

	spin_unlock(&iface->lock);

	return IRQ_HANDLED;

}



static void s6i2c_timeout(unsigned long data)

{

	struct s6i2c_if *iface = (struct s6i2c_if *)data;

	unsigned long flags;



	spin_lock_irqsave(&iface->lock, flags);

	s6i2c_handle_interrupt(iface);

	if (--iface->timeout_count > 0) {

		iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;

		add_timer(&iface->timeout_timer);

	} else {

		complete(&iface->complete);

		i2c_wr16(iface, S6_I2C_INTRMASK, 0);

	}

	spin_unlock_irqrestore(&iface->lock, flags);

}



static int s6i2c_master_xfer(struct i2c_adapter *adap,

				struct i2c_msg *msgs, int num)

{

	struct s6i2c_if *iface = adap->algo_data;

	int i;

	if (num == 0)

		return 0;

	if (i2c_rd16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_ACTIVITY))

		yield();

	i2c_wr16(iface, S6_I2C_INTRMASK, 0);

	i2c_rd16(iface, S6_I2C_CLRINTR);

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

		if (msgs[i].flags & I2C_M_TEN) {

			dev_err(&adap->dev,

				"s6i2c: 10 bits addr not supported\n");

			return -EINVAL;

		}

		if (msgs[i].len == 0) {

			dev_err(&adap->dev,

				"s6i2c: zero length message not supported\n");

			return -EINVAL;

		}

		if (msgs[i].addr != msgs[0].addr) {

			dev_err(&adap->dev,

				"s6i2c: multiple xfer cannot change target\n");

			return -EINVAL;

		}

	}



	iface->msgs = msgs;

	iface->msgs_num = num;

	iface->msgs_push = 0;

	iface->msgs_done = 0;

	iface->push = 0;

	iface->done = 0;

	iface->timeout_count = 10;

	i2c_wr16(iface, S6_I2C_TAR, msgs[0].addr);

	i2c_wr16(iface, S6_I2C_ENABLE, 1);

	i2c_wr16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXEMPTY) |

					 (1 << S6_I2C_INTR_TXABRT));



	iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;

	add_timer(&iface->timeout_timer);

	wait_for_completion(&iface->complete);

	del_timer_sync(&iface->timeout_timer);

	while (i2c_rd32(iface, S6_I2C_TXFLR) > 0)

		schedule();

	while (i2c_rd16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_ACTIVITY))

		schedule();



	i2c_wr16(iface, S6_I2C_INTRMASK, 0);

	i2c_wr16(iface, S6_I2C_ENABLE, 0);

	return iface->msgs_done;

}



static u32 s6i2c_functionality(struct i2c_adapter *adap)

{

	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;

}



static struct i2c_algorithm s6i2c_algorithm = {

	.master_xfer   = s6i2c_master_xfer,

	.functionality = s6i2c_functionality,

};



static u16 __devinit nanoseconds_on_clk(struct s6i2c_if *iface, u32 ns)

{

	u32 dividend = ((clk_get_rate(iface->clk) / 1000) * ns) / 1000000;

	if (dividend > 0xffff)

		return 0xffff;

	return dividend;

}



static int __devinit s6i2c_probe(struct platform_device *dev)

{

	struct s6i2c_if *iface = &s6i2c_if;

	struct i2c_adapter *p_adap;

	const char *clock;

	int bus_num, rc;

	spin_lock_init(&iface->lock);

	init_completion(&iface->complete);

	iface->irq = platform_get_irq(dev, 0);

	if (iface->irq < 0) {

		rc = iface->irq;

		goto err_out;

	}

	iface->res = platform_get_resource(dev, IORESOURCE_MEM, 0);

	if (!iface->res) {

		rc = -ENXIO;

		goto err_out;

	}

	iface->res = request_mem_region(iface->res->start,

					resource_size(iface->res),

					dev->dev.bus_id);

	if (!iface->res) {

		rc = -EBUSY;

		goto err_out;

	}

	iface->reg = ioremap_nocache(iface->res->start,

				     resource_size(iface->res));

	if (!iface->reg) {

		rc = -ENOMEM;

		goto err_reg;

	}



	clock = 0;

	bus_num = -1;

	if (dev->dev.platform_data) {

		struct s6_i2c_platform_data *pdata = dev->dev.platform_data;

		bus_num = pdata->bus_num;

		clock = pdata->clock;

	}

	iface->clk = clk_get(&dev->dev, clock);

	if (IS_ERR(iface->clk)) {

		rc = PTR_ERR(iface->clk);

		goto err_map;

	}

	rc = clk_enable(iface->clk);

	if (rc < 0)

		goto err_clk_put;

	init_timer(&iface->timeout_timer);

	iface->timeout_timer.function = s6i2c_timeout;

	iface->timeout_timer.data = (unsigned long)iface;



	p_adap = &iface->adap;

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

	p_adap->algo = &s6i2c_algorithm;

	p_adap->algo_data = iface;

	p_adap->nr = bus_num;

	p_adap->class = 0;

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

	i2c_wr16(iface, S6_I2C_INTRMASK, 0);

	rc = request_irq(iface->irq, s6i2c_interrupt_entry,

			 IRQF_SHARED, dev->name, iface);

	if (rc) {

		dev_err(&p_adap->dev, "s6i2c: cant get IRQ %d\n", iface->irq);

		goto err_clk_dis;

	}



	i2c_wr16(iface, S6_I2C_ENABLE, 0);

	udelay(1);

	i2c_wr32(iface, S6_I2C_SRESET, 1 << S6_I2C_SRESET_IC_SRST);

	i2c_wr16(iface, S6_I2C_CLRTXABRT, 1);

	i2c_wr16(iface, S6_I2C_CON,

			(1 << S6_I2C_CON_MASTER) |

			(S6_I2C_CON_SPEED_NORMAL << S6_I2C_CON_SPEED) |

			(0 << S6_I2C_CON_10BITSLAVE) |

			(0 << S6_I2C_CON_10BITMASTER) |

			(1 << S6_I2C_CON_RESTARTENA) |

			(1 << S6_I2C_CON_SLAVEDISABLE));

	i2c_wr16(iface, S6_I2C_SSHCNT, nanoseconds_on_clk(iface, 4000));

	i2c_wr16(iface, S6_I2C_SSLCNT, nanoseconds_on_clk(iface, 4700));

	i2c_wr16(iface, S6_I2C_FSHCNT, nanoseconds_on_clk(iface, 600));

	i2c_wr16(iface, S6_I2C_FSLCNT, nanoseconds_on_clk(iface, 1300));

	i2c_wr16(iface, S6_I2C_RXTL, 0);

	i2c_wr16(iface, S6_I2C_TXTL, 0);



	platform_set_drvdata(dev, iface);

	if (bus_num < 0)

		rc = i2c_add_adapter(p_adap);

	else

		rc = i2c_add_numbered_adapter(p_adap);

	if (rc)

		goto err_irq_free;

	return 0;



err_irq_free:

	free_irq(iface->irq, iface);

err_clk_dis:

	clk_disable(iface->clk);

err_clk_put:

	clk_put(iface->clk);

err_map:

	iounmap(iface->reg);

err_reg:

	release_mem_region(iface->res->start,

			   resource_size(iface->res));

err_out:

	return rc;

}



static int __devexit s6i2c_remove(struct platform_device *pdev)

{

	struct s6i2c_if *iface = platform_get_drvdata(pdev);

	i2c_wr16(iface, S6_I2C_ENABLE, 0);

	platform_set_drvdata(pdev, NULL);

	i2c_del_adapter(&iface->adap);

	free_irq(iface->irq, iface);

	clk_disable(iface->clk);

	clk_put(iface->clk);

	iounmap(iface->reg);

	release_mem_region(iface->res->start,

			   resource_size(iface->res));

	return 0;

}



static struct platform_driver s6i2c_driver = {

	.probe		= s6i2c_probe,

	.remove		= __devexit_p(s6i2c_remove),

	.driver		= {

		.name	= DRV_NAME,

		.owner	= THIS_MODULE,

	},

};



static int __init s6i2c_init(void)

{

	pr_info("I2C: S6000 I2C driver\n");

	return platform_driver_register(&s6i2c_driver);

}



static void __exit s6i2c_exit(void)

{

	platform_driver_unregister(&s6i2c_driver);

}



MODULE_DESCRIPTION("I2C-Bus adapter routines for S6000 I2C");

MODULE_LICENSE("GPL");

MODULE_ALIAS("platform:" DRV_NAME);



subsys_initcall(s6i2c_init);

module_exit(s6i2c_exit);

drivers/i2c/busses/i2c-s6000.h

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/*

 * drivers/i2c/busses/i2c-s6000.h

 *

 * This file is subject to the terms and conditions of the GNU General Public

 * License.  See the file "COPYING" in the main directory of this archive

 * for more details.

 *

 * Copyright (C) 2008 Emlix GmbH <info@emlix.com>

 * Author:	Oskar Schirmer <os@emlix.com>

 */



#ifndef __DRIVERS_I2C_BUSSES_I2C_S6000_H

#define __DRIVERS_I2C_BUSSES_I2C_S6000_H



#define S6_I2C_CON		0x000

#define S6_I2C_CON_MASTER		0

#define S6_I2C_CON_SPEED		1

#define S6_I2C_CON_SPEED_NORMAL			1

#define S6_I2C_CON_SPEED_FAST			2

#define S6_I2C_CON_SPEED_MASK			3

#define S6_I2C_CON_10BITSLAVE		3

#define S6_I2C_CON_10BITMASTER		4

#define S6_I2C_CON_RESTARTENA		5

#define S6_I2C_CON_SLAVEDISABLE		6

#define S6_I2C_TAR		0x004

#define S6_I2C_TAR_GCORSTART		10

#define S6_I2C_TAR_SPECIAL		11

#define S6_I2C_SAR		0x008

#define S6_I2C_HSMADDR		0x00C

#define S6_I2C_DATACMD		0x010

#define S6_I2C_DATACMD_READ		8

#define S6_I2C_SSHCNT		0x014

#define S6_I2C_SSLCNT		0x018

#define S6_I2C_FSHCNT		0x01C

#define S6_I2C_FSLCNT		0x020

#define S6_I2C_INTRSTAT		0x02C

#define S6_I2C_INTRMASK		0x030

#define S6_I2C_RAWINTR		0x034

#define S6_I2C_INTR_RXUNDER		0

#define S6_I2C_INTR_RXOVER		1

#define S6_I2C_INTR_RXFULL		2

#define S6_I2C_INTR_TXOVER		3

#define S6_I2C_INTR_TXEMPTY		4

#define S6_I2C_INTR_RDREQ		5

#define S6_I2C_INTR_TXABRT		6

#define S6_I2C_INTR_RXDONE		7

#define S6_I2C_INTR_ACTIVITY		8

#define S6_I2C_INTR_STOPDET		9

#define S6_I2C_INTR_STARTDET		10

#define S6_I2C_INTR_GENCALL		11

#define S6_I2C_RXTL		0x038

#define S6_I2C_TXTL		0x03C

#define S6_I2C_CLRINTR		0x040

#define S6_I2C_CLRRXUNDER	0x044

#define S6_I2C_CLRRXOVER	0x048

#define S6_I2C_CLRTXOVER	0x04C

#define S6_I2C_CLRRDREQ		0x050

#define S6_I2C_CLRTXABRT	0x054

#define S6_I2C_CLRRXDONE	0x058

#define S6_I2C_CLRACTIVITY	0x05C

#define S6_I2C_CLRSTOPDET	0x060

#define S6_I2C_CLRSTARTDET	0x064

#define S6_I2C_CLRGENCALL	0x068

#define S6_I2C_ENABLE		0x06C

#define S6_I2C_STATUS		0x070

#define S6_I2C_STATUS_ACTIVITY		0

#define S6_I2C_STATUS_TFNF		1

#define S6_I2C_STATUS_TFE		2

#define S6_I2C_STATUS_RFNE		3

#define S6_I2C_STATUS_RFF		4

#define S6_I2C_TXFLR		0x074

#define S6_I2C_RXFLR		0x078

#define S6_I2C_SRESET		0x07C

#define S6_I2C_SRESET_IC_SRST		0

#define S6_I2C_SRESET_IC_MASTER_SRST	1

#define S6_I2C_SRESET_IC_SLAVE_SRST	2

#define S6_I2C_TXABRTSOURCE	0x080



#endif

include/linux/i2c/s6000.h

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#ifndef __LINUX_I2C_S6000_H

#define __LINUX_I2C_S6000_H



struct s6_i2c_platform_data {

	const char *clock; /* the clock to use */

	int bus_num; /* the bus number to register */

};



#endif