/*
* Copyright (C) 2002 Motorola GSG-China
*
* 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.
*
* Author:
* Darius Augulis, Teltonika Inc.
*
* Desc.:
* Implementation of I2C Adapter/Algorithm Driver
* for I2C Bus integrated in Freescale i.MX/MXC processors
*
* Derived from Motorola GSG China I2C example driver
*
* Copyright (C) 2005 Torsten Koschorrek <koschorrek at synertronixx.de
* Copyright (C) 2005 Matthias Blaschke <blaschke at synertronixx.de
* Copyright (C) 2007 RightHand Technologies, Inc.
* Copyright (C) 2008 Darius Augulis <darius.augulis at teltonika.lt>
*
*/
/** Includes *******************************************************************
*******************************************************************************/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/io.h>
#include <linux/sched.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <mach/irqs.h>
#include <mach/hardware.h>
#include <mach/i2c.h>
/** Defines ********************************************************************
*******************************************************************************/
/* This will be the driver name the kernel reports */
#define DRIVER_NAME "imx-i2c"
/* Default value */
#define IMX_I2C_BIT_RATE 100000 /* 100kHz */
/* IMX I2C registers */
#define IMX_I2C_IADR 0x00 /* i2c slave address */
#define IMX_I2C_IFDR 0x04 /* i2c frequency divider */
#define IMX_I2C_I2CR 0x08 /* i2c control */
#define IMX_I2C_I2SR 0x0C /* i2c status */
#define IMX_I2C_I2DR 0x10 /* i2c transfer data */
/* Bits of IMX I2C registers */
#define I2SR_RXAK 0x01
#define I2SR_IIF 0x02
#define I2SR_SRW 0x04
#define I2SR_IAL 0x10
#define I2SR_IBB 0x20
#define I2SR_IAAS 0x40
#define I2SR_ICF 0x80
#define I2CR_RSTA 0x04
#define I2CR_TXAK 0x08
#define I2CR_MTX 0x10
#define I2CR_MSTA 0x20
#define I2CR_IIEN 0x40
#define I2CR_IEN 0x80
/** Variables ******************************************************************
*******************************************************************************/
/*
* sorted list of clock divider, register value pairs
* taken from table 26-5, p.26-9, Freescale i.MX
* Integrated Portable System Processor Reference Manual
* Document Number: MC9328MXLRM, Rev. 5.1, 06/2007
*
* Duplicated divider values removed from list
*/
static u16 __initdata i2c_clk_div[50][2] = {
{ 22, 0x20 }, { 24, 0x21 }, { 26, 0x22 }, { 28, 0x23 },
{ 30, 0x00 }, { 32, 0x24 }, { 36, 0x25 }, { 40, 0x26 },
{ 42, 0x03 }, { 44, 0x27 }, { 48, 0x28 }, { 52, 0x05 },
{ 56, 0x29 }, { 60, 0x06 }, { 64, 0x2A }, { 72, 0x2B },
{ 80, 0x2C }, { 88, 0x09 }, { 96, 0x2D }, { 104, 0x0A },
{ 112, 0x2E }, { 128, 0x2F }, { 144, 0x0C }, { 160, 0x30 },
{ 192, 0x31 }, { 224, 0x32 }, { 240, 0x0F }, { 256, 0x33 },
{ 288, 0x10 }, { 320, 0x34 }, { 384, 0x35 }, { 448, 0x36 },
{ 480, 0x13 }, { 512, 0x37 }, { 576, 0x14 }, { 640, 0x38 },
{ 768, 0x39 }, { 896, 0x3A }, { 960, 0x17 }, { 1024, 0x3B },
{ 1152, 0x18 }, { 1280, 0x3C }, { 1536, 0x3D }, { 1792, 0x3E },
{ 1920, 0x1B }, { 2048, 0x3F }, { 2304, 0x1C }, { 2560, 0x1D },
{ 3072, 0x1E }, { 3840, 0x1F }
};
struct imx_i2c_struct {
struct i2c_adapter adapter;
struct resource *res;
struct clk *clk;
void __iomem *base;
int irq;
wait_queue_head_t queue;
unsigned long i2csr;
unsigned int disable_delay;
};
/** Functions for IMX I2C adapter driver ***************************************
*******************************************************************************/
static int i2c_imx_bus_busy(struct imx_i2c_struct *i2c_imx)
{
unsigned long orig_jiffies = jiffies;
dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
/* wait for bus not busy */
while (readb(i2c_imx->base + IMX_I2C_I2SR) & I2SR_IBB) {
if (signal_pending(current)) {
dev_dbg(&i2c_imx->adapter.dev,
"<%s> I2C Interrupted\n", __func__);
return -EINTR;
}
if (time_after(jiffies, orig_jiffies + HZ / 1000)) {
dev_dbg(&i2c_imx->adapter.dev,
"<%s> I2C bus is busy\n", __func__);
return -EIO;
}
schedule();
}
return 0;
}
static int i2c_imx_trx_complete(struct imx_i2c_struct *i2c_imx)
{
int result;
result = wait_event_interruptible_timeout(i2c_imx->queue,
i2c_imx->i2csr & I2SR_IIF, HZ / 10);
if (unlikely(result < 0)) {
dev_dbg(&i2c_imx->adapter.dev, "<%s> result < 0\n", __func__);
return result;
} else if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) {
dev_dbg(&i2c_imx->adapter.dev, "<%s> Timeout\n", __func__);
return -ETIMEDOUT;
}
dev_dbg(&i2c_imx->adapter.dev, "<%s> TRX complete\n", __func__);
i2c_imx->i2csr = 0;
return 0;
}
static int i2c_imx_acked(struct imx_i2c_struct *i2c_imx)
{
if (readb(i2c_imx->base + IMX_I2C_I2SR) & I2SR_RXAK) {
dev_dbg(&i2c_imx->adapter.dev, "<%s> No ACK\n", __func__);
return -EIO; /* No ACK */
}
dev_dbg(&i2c_imx->adapter.dev, "<%s> ACK received\n", __func__);
return 0;
}
static void i2c_imx_start(struct imx_i2c_struct *i2c_imx)
{
unsigned int temp = 0;
dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
/* Enable I2C controller */
writeb(I2CR_IEN, i2c_imx->base + IMX_I2C_I2CR);
/* Start I2C transaction */
temp = readb(i2c_imx->base + IMX_I2C_I2CR);
temp |= I2CR_MSTA;
writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
temp |= I2CR_IIEN | I2CR_MTX | I2CR_TXAK;
writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
}
static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx)
{
unsigned int temp = 0;
/* Stop I2C transaction */
dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
temp = readb(i2c_imx->base + IMX_I2C_I2CR);
temp &= ~I2CR_MSTA;
writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
/* setup chip registers to defaults */
writeb(I2CR_IEN, i2c_imx->base + IMX_I2C_I2CR);
writeb(0, i2c_imx->base + IMX_I2C_I2SR);
/*
* This delay caused by an i.MXL hardware bug.
* If no (or too short) delay, no "STOP" bit will be generated.
*/
udelay(i2c_imx->disable_delay);
/* Disable I2C controller */
writeb(0, i2c_imx->base + IMX_I2C_I2CR);
}
static void __init i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx,
unsigned int rate)
{
unsigned int i2c_clk_rate;
unsigned int div;
int i;
/* Divider value calculation */
i2c_clk_rate = clk_get_rate(i2c_imx->clk);
div = (i2c_clk_rate + rate - 1) / rate;
if (div < i2c_clk_div[0][0])
i = 0;
else if (div > i2c_clk_div[ARRAY_SIZE(i2c_clk_div) - 1][0])
i = ARRAY_SIZE(i2c_clk_div) - 1;
else
for (i = 0; i2c_clk_div[i][0] < div; i++);
/* Write divider value to register */
writeb(i2c_clk_div[i][1], i2c_imx->base + IMX_I2C_IFDR);
/*
* There dummy delay is calculated.
* It should be about one I2C clock period long.
* This delay is used in I2C bus disable function
* to fix chip hardware bug.
*/
i2c_imx->disable_delay = (500000U * i2c_clk_div[i][0]
+ (i2c_clk_rate / 2) - 1) / (i2c_clk_rate / 2);
/* dev_dbg() can't be used, because adapter is not yet registered */
#ifdef CONFIG_I2C_DEBUG_BUS
printk(KERN_DEBUG "I2C: <%s> I2C_CLK=%d, REQ DIV=%d\n",
__func__, i2c_clk_rate, div);
printk(KERN_DEBUG "I2C: <%s> IFDR[IC]=0x%x, REAL DIV=%d\n",
__func__, i2c_clk_div[i][1], i2c_clk_div[i][0]);
#endif
}
static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
{
struct imx_i2c_struct *i2c_imx = dev_id;
unsigned int temp;
temp = readb(i2c_imx->base + IMX_I2C_I2SR);
if (temp & I2SR_IIF) {
/* save status register */
i2c_imx->i2csr = temp;
temp &= ~I2SR_IIF;
writeb(temp, i2c_imx->base + IMX_I2C_I2SR);
wake_up_interruptible(&i2c_imx->queue);
return IRQ_HANDLED;
}
return IRQ_NONE;
}
static int i2c_imx_write(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs)
{
int i, result;
dev_dbg(&i2c_imx->adapter.dev, "<%s> write slave address: addr=0x%x\n",
__func__, msgs->addr << 1);
/* write slave address */
writeb(msgs->addr << 1, i2c_imx->base + IMX_I2C_I2DR);
result = i2c_imx_trx_complete(i2c_imx);
if (result)
return result;
result = i2c_imx_acked(i2c_imx);
if (result)
return result;
dev_dbg(&i2c_imx->adapter.dev, "<%s> write data\n", __func__);
/* write data */
for (i = 0; i < msgs->len; i++) {
dev_dbg(&i2c_imx->adapter.dev,
"<%s> write byte: B%d=0x%X\n",
__func__, i, msgs->buf[i]);
writeb(msgs->buf[i], i2c_imx->base + IMX_I2C_I2DR);
result = i2c_imx_trx_complete(i2c_imx);
if (result)
return result;
result = i2c_imx_acked(i2c_imx);
if (result)
return result;
}
return 0;
}
static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs)
{
int i, result;
unsigned int temp;
dev_dbg(&i2c_imx->adapter.dev,
"<%s> write slave address: addr=0x%x\n",
__func__, (msgs->addr << 1) | 0x01);
/* write slave address */
writeb((msgs->addr << 1) | 0x01, i2c_imx->base + IMX_I2C_I2DR);
result = i2c_imx_trx_complete(i2c_imx);
if (result)
return result;
result = i2c_imx_acked(i2c_imx);
if (result)
return result;
dev_dbg(&i2c_imx->adapter.dev, "<%s> setup bus\n", __func__);
/* setup bus to read data */
temp = readb(i2c_imx->base + IMX_I2C_I2CR);
temp &= ~I2CR_MTX;
if (msgs->len - 1)
temp &= ~I2CR_TXAK;
writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
readb(i2c_imx->base + IMX_I2C_I2DR); /* dummy read */
dev_dbg(&i2c_imx->adapter.dev, "<%s> read data\n", __func__);
/* read data */
for (i = 0; i < msgs->len; i++) {
result = i2c_imx_trx_complete(i2c_imx);
if (result)
return result;
if (i == (msgs->len - 1)) {
dev_dbg(&i2c_imx->adapter.dev,
"<%s> clear MSTA\n", __func__);
temp = readb(i2c_imx->base + IMX_I2C_I2CR);
temp &= ~I2CR_MSTA;
writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
} else if (i == (msgs->len - 2)) {
dev_dbg(&i2c_imx->adapter.dev,
"<%s> set TXAK\n", __func__);
temp = readb(i2c_imx->base + IMX_I2C_I2CR);
temp |= I2CR_TXAK;
writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
}
msgs->buf[i] = readb(i2c_imx->base + IMX_I2C_I2DR);
dev_dbg(&i2c_imx->adapter.dev,
"<%s> read byte: B%d=0x%X\n",
__func__, i, msgs->buf[i]);
}
return 0;
}
static int i2c_imx_xfer(struct i2c_adapter *adapter,
struct i2c_msg *msgs, int num)
{
unsigned int i, temp;
int result;
struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(adapter);
dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
/* Check if i2c bus is not busy */
result = i2c_imx_bus_busy(i2c_imx);
if (result)
goto fail0;
/* Start I2C transfer */
i2c_imx_start(i2c_imx);
/* read/write data */
for (i = 0; i < num; i++) {
if (i) {
dev_dbg(&i2c_imx->adapter.dev,
"<%s> repeated start\n", __func__);
temp = readb(i2c_imx->base + IMX_I2C_I2CR);
temp |= I2CR_RSTA;
writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
}
dev_dbg(&i2c_imx->adapter.dev,
"<%s> transfer message: %d\n", __func__, i);
/* write/read data */
#ifdef CONFIG_I2C_DEBUG_BUS
temp = readb(i2c_imx->base + IMX_I2C_I2CR);
dev_dbg(&i2c_imx->adapter.dev, "<%s> CONTROL: IEN=%d, IIEN=%d, "
"MSTA=%d, MTX=%d, TXAK=%d, RSTA=%d\n", __func__,
(temp & I2CR_IEN ? 1 : 0), (temp & I2CR_IIEN ? 1 : 0),
(temp & I2CR_MSTA ? 1 : 0), (temp & I2CR_MTX ? 1 : 0),
(temp & I2CR_TXAK ? 1 : 0), (temp & I2CR_RSTA ? 1 : 0));
temp = readb(i2c_imx->base + IMX_I2C_I2SR);
dev_dbg(&i2c_imx->adapter.dev,
"<%s> STATUS: ICF=%d, IAAS=%d, IBB=%d, "
"IAL=%d, SRW=%d, IIF=%d, RXAK=%d\n", __func__,
(temp & I2SR_ICF ? 1 : 0), (temp & I2SR_IAAS ? 1 : 0),
(temp & I2SR_IBB ? 1 : 0), (temp & I2SR_IAL ? 1 : 0),
(temp & I2SR_SRW ? 1 : 0), (temp & I2SR_IIF ? 1 : 0),
(temp & I2SR_RXAK ? 1 : 0));
#endif
if (msgs[i].flags & I2C_M_RD)
result = i2c_imx_read(i2c_imx, &msgs[i]);
else
result = i2c_imx_write(i2c_imx, &msgs[i]);
}
fail0:
/* Stop I2C transfer */
i2c_imx_stop(i2c_imx);
dev_dbg(&i2c_imx->adapter.dev, "<%s> exit with: %s: %d\n", __func__,
(result < 0) ? "error" : "success msg",
(result < 0) ? result : num);
return (result < 0) ? result : num;
}
static u32 i2c_imx_func(struct i2c_adapter *adapter)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}
static struct i2c_algorithm i2c_imx_algo = {
.master_xfer = i2c_imx_xfer,
.functionality = i2c_imx_func,
};
static int __init i2c_imx_probe(struct platform_device *pdev)
{
struct imx_i2c_struct *i2c_imx;
struct resource *res;
struct imxi2c_platform_data *pdata;
void __iomem *base;
resource_size_t res_size;
int irq;
int ret;
dev_dbg(&pdev->dev, "<%s>\n", __func__);
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res) {
dev_err(&pdev->dev, "can't get device resources\n");
return -ENOENT;
}
irq = platform_get_irq(pdev, 0);
if (irq < 0) {
dev_err(&pdev->dev, "can't get irq number\n");
return -ENOENT;
}
pdata = pdev->dev.platform_data;
if (pdata && pdata->init) {
ret = pdata->init(&pdev->dev);
if (ret)
return ret;
}
res_size = resource_size(res);
base = ioremap(res->start, res_size);
if (!base) {
dev_err(&pdev->dev, "ioremap failed\n");
ret = -EIO;
goto fail0;
}
i2c_imx = kzalloc(sizeof(struct imx_i2c_struct), GFP_KERNEL);
if (!i2c_imx) {
dev_err(&pdev->dev, "can't allocate interface\n");
ret = -ENOMEM;
goto fail1;
}
if (!request_mem_region(res->start, res_size, DRIVER_NAME)) {
ret = -EBUSY;
goto fail2;
}
/* Setup i2c_imx driver structure */
strcpy(i2c_imx->adapter.name, pdev->name);
i2c_imx->adapter.owner = THIS_MODULE;
i2c_imx->adapter.algo = &i2c_imx_algo;
i2c_imx->adapter.dev.parent = &pdev->dev;
i2c_imx->adapter.nr = pdev->id;
i2c_imx->irq = irq;
i2c_imx->base = base;
i2c_imx->res = res;
/* Get I2C clock */
i2c_imx->clk = clk_get(&pdev->dev, "i2c_clk");
if (IS_ERR(i2c_imx->clk)) {
ret = PTR_ERR(i2c_imx->clk);
dev_err(&pdev->dev, "can't get I2C clock\n");
goto fail3;
}
clk_enable(i2c_imx->clk);
/* Request IRQ */
ret = request_irq(i2c_imx->irq, i2c_imx_isr, 0, pdev->name, i2c_imx);
if (ret) {
dev_err(&pdev->dev, "can't claim irq %d\n", i2c_imx->irq);
goto fail4;
}
/* Init queue */
init_waitqueue_head(&i2c_imx->queue);
/* Set up adapter data */
i2c_set_adapdata(&i2c_imx->adapter, i2c_imx);
/* Set up clock divider */
if (pdata && pdata->bitrate)
i2c_imx_set_clk(i2c_imx, pdata->bitrate);
else
i2c_imx_set_clk(i2c_imx, IMX_I2C_BIT_RATE);
/* Set up chip registers to defaults */
writeb(0, i2c_imx->base + IMX_I2C_I2CR);
writeb(0, i2c_imx->base + IMX_I2C_I2SR);
/* Add I2C adapter */
ret = i2c_add_numbered_adapter(&i2c_imx->adapter);
if (ret < 0) {
dev_err(&pdev->dev, "registration failed\n");
goto fail5;
}
/* Set up platform driver data */
platform_set_drvdata(pdev, i2c_imx);
dev_dbg(&i2c_imx->adapter.dev, "claimed irq %d\n", i2c_imx->irq);
dev_dbg(&i2c_imx->adapter.dev, "device resources from 0x%x to 0x%x\n",
i2c_imx->res->start, i2c_imx->res->end);
dev_dbg(&i2c_imx->adapter.dev, "allocated %d bytes at 0x%x \n",
res_size, i2c_imx->res->start);
dev_dbg(&i2c_imx->adapter.dev, "adapter name: \"%s\"\n",
i2c_imx->adapter.name);
dev_dbg(&i2c_imx->adapter.dev, "IMX I2C adapter registered\n");
return 0; /* Return OK */
fail5:
free_irq(i2c_imx->irq, i2c_imx);
fail4:
clk_disable(i2c_imx->clk);
clk_put(i2c_imx->clk);
fail3:
release_mem_region(i2c_imx->res->start, resource_size(res));
fail2:
kfree(i2c_imx);
fail1:
iounmap(base);
fail0:
if (pdata && pdata->exit)
pdata->exit(&pdev->dev);
return ret; /* Return error number */
}
static int __exit i2c_imx_remove(struct platform_device *pdev)
{
struct imx_i2c_struct *i2c_imx = platform_get_drvdata(pdev);
struct imxi2c_platform_data *pdata = pdev->dev.platform_data;
/* remove adapter */
dev_dbg(&i2c_imx->adapter.dev, "adapter removed\n");
i2c_del_adapter(&i2c_imx->adapter);
platform_set_drvdata(pdev, NULL);
/* free interrupt */
free_irq(i2c_imx->irq, i2c_imx);
/* setup chip registers to defaults */
writeb(0, i2c_imx->base + IMX_I2C_IADR);
writeb(0, i2c_imx->base + IMX_I2C_IFDR);
writeb(0, i2c_imx->base + IMX_I2C_I2CR);
writeb(0, i2c_imx->base + IMX_I2C_I2SR);
/* Shut down hardware */
if (pdata && pdata->exit)
pdata->exit(&pdev->dev);
/* Disable I2C clock */
clk_disable(i2c_imx->clk);
clk_put(i2c_imx->clk);
release_mem_region(i2c_imx->res->start, resource_size(i2c_imx->res));
iounmap(i2c_imx->base);
kfree(i2c_imx);
return 0;
}
static struct platform_driver i2c_imx_driver = {
.probe = i2c_imx_probe,
.remove = __exit_p(i2c_imx_remove),
.driver = {
.name = DRIVER_NAME,
.owner = THIS_MODULE,
}
};
static int __init i2c_adap_imx_init(void)
{
return platform_driver_probe(&i2c_imx_driver, i2c_imx_probe);
}
subsys_initcall(i2c_adap_imx_init);
static void __exit i2c_adap_imx_exit(void)
{
platform_driver_unregister(&i2c_imx_driver);
}
module_exit(i2c_adap_imx_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Darius Augulis");
MODULE_DESCRIPTION("I2C adapter driver for IMX I2C bus");
MODULE_ALIAS("platform:" DRIVER_NAME);
