/*
* Synopsys Designware I2C adapter driver (master only).
*
* Based on the TI DAVINCI I2C adapter driver.
*
* Copyright (C) 2006 Texas Instruments.
* Copyright (C) 2007 MontaVista Software Inc.
* Copyright (C) 2009 Provigent Ltd.
*
* ----------------------------------------------------------------------------
*
* 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., 675 Mass Ave, Cambridge, MA 02139, USA.
* ----------------------------------------------------------------------------
*
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/clk.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/io.h>
/*
* Registers offset
*/
#define DW_IC_CON 0x0
#define DW_IC_TAR 0x4
#define DW_IC_DATA_CMD 0x10
#define DW_IC_SS_SCL_HCNT 0x14
#define DW_IC_SS_SCL_LCNT 0x18
#define DW_IC_FS_SCL_HCNT 0x1c
#define DW_IC_FS_SCL_LCNT 0x20
#define DW_IC_INTR_STAT 0x2c
#define DW_IC_INTR_MASK 0x30
#define DW_IC_CLR_INTR 0x40
#define DW_IC_ENABLE 0x6c
#define DW_IC_STATUS 0x70
#define DW_IC_TXFLR 0x74
#define DW_IC_RXFLR 0x78
#define DW_IC_COMP_PARAM_1 0xf4
#define DW_IC_TX_ABRT_SOURCE 0x80
#define DW_IC_CON_MASTER 0x1
#define DW_IC_CON_SPEED_STD 0x2
#define DW_IC_CON_SPEED_FAST 0x4
#define DW_IC_CON_10BITADDR_MASTER 0x10
#define DW_IC_CON_RESTART_EN 0x20
#define DW_IC_CON_SLAVE_DISABLE 0x40
#define DW_IC_INTR_TX_EMPTY 0x10
#define DW_IC_INTR_TX_ABRT 0x40
#define DW_IC_INTR_STOP_DET 0x200
#define DW_IC_STATUS_ACTIVITY 0x1
#define DW_IC_ERR_TX_ABRT 0x1
/*
* status codes
*/
#define STATUS_IDLE 0x0
#define STATUS_WRITE_IN_PROGRESS 0x1
#define STATUS_READ_IN_PROGRESS 0x2
#define TIMEOUT 20 /* ms */
/*
* hardware abort codes from the DW_IC_TX_ABRT_SOURCE register
*
* only expected abort codes are listed here
* refer to the datasheet for the full list
*/
#define ABRT_7B_ADDR_NOACK 0
#define ABRT_10ADDR1_NOACK 1
#define ABRT_10ADDR2_NOACK 2
#define ABRT_TXDATA_NOACK 3
#define ABRT_GCALL_NOACK 4
#define ABRT_GCALL_READ 5
#define ABRT_SBYTE_ACKDET 7
#define ABRT_SBYTE_NORSTRT 9
#define ABRT_10B_RD_NORSTRT 10
#define ARB_MASTER_DIS 11
#define ARB_LOST 12
static char *abort_sources[] = {
[ABRT_7B_ADDR_NOACK] =
"slave address not acknowledged (7bit mode)",
[ABRT_10ADDR1_NOACK] =
"first address byte not acknowledged (10bit mode)",
[ABRT_10ADDR2_NOACK] =
"second address byte not acknowledged (10bit mode)",
[ABRT_TXDATA_NOACK] =
"data not acknowledged",
[ABRT_GCALL_NOACK] =
"no acknowledgement for a general call",
[ABRT_GCALL_READ] =
"read after general call",
[ABRT_SBYTE_ACKDET] =
"start byte acknowledged",
[ABRT_SBYTE_NORSTRT] =
"trying to send start byte when restart is disabled",
[ABRT_10B_RD_NORSTRT] =
"trying to read when restart is disabled (10bit mode)",
[ARB_MASTER_DIS] =
"trying to use disabled adapter",
[ARB_LOST] =
"lost arbitration",
};
/**
* struct dw_i2c_dev - private i2c-designware data
* @dev: driver model device node
* @base: IO registers pointer
* @cmd_complete: tx completion indicator
* @pump_msg: continue in progress transfers
* @lock: protect this struct and IO registers
* @clk: input reference clock
* @cmd_err: run time hadware error code
* @msgs: points to an array of messages currently being transfered
* @msgs_num: the number of elements in msgs
* @msg_write_idx: the element index of the current tx message in the msgs
* array
* @tx_buf_len: the length of the current tx buffer
* @tx_buf: the current tx buffer
* @msg_read_idx: the element index of the current rx message in the msgs
* array
* @rx_buf_len: the length of the current rx buffer
* @rx_buf: the current rx buffer
* @msg_err: error status of the current transfer
* @status: i2c master status, one of STATUS_*
* @abort_source: copy of the TX_ABRT_SOURCE register
* @irq: interrupt number for the i2c master
* @adapter: i2c subsystem adapter node
* @tx_fifo_depth: depth of the hardware tx fifo
* @rx_fifo_depth: depth of the hardware rx fifo
*/
struct dw_i2c_dev {
struct device *dev;
void __iomem *base;
struct completion cmd_complete;
struct tasklet_struct pump_msg;
struct mutex lock;
struct clk *clk;
int cmd_err;
struct i2c_msg *msgs;
int msgs_num;
int msg_write_idx;
u16 tx_buf_len;
u8 *tx_buf;
int msg_read_idx;
u16 rx_buf_len;
u8 *rx_buf;
int msg_err;
unsigned int status;
u16 abort_source;
int irq;
struct i2c_adapter adapter;
unsigned int tx_fifo_depth;
unsigned int rx_fifo_depth;
};
/**
* i2c_dw_init() - initialize the designware i2c master hardware
* @dev: device private data
*
* This functions configures and enables the I2C master.
* This function is called during I2C init function, and in case of timeout at
* run time.
*/
static void i2c_dw_init(struct dw_i2c_dev *dev)
{
u32 input_clock_khz = clk_get_rate(dev->clk) / 1000;
u16 ic_con;
/* Disable the adapter */
writeb(0, dev->base + DW_IC_ENABLE);
/* set standard and fast speed deviders for high/low periods */
writew((input_clock_khz * 40 / 10000)+1, /* std speed high, 4us */
dev->base + DW_IC_SS_SCL_HCNT);
writew((input_clock_khz * 47 / 10000)+1, /* std speed low, 4.7us */
dev->base + DW_IC_SS_SCL_LCNT);
writew((input_clock_khz * 6 / 10000)+1, /* fast speed high, 0.6us */
dev->base + DW_IC_FS_SCL_HCNT);
writew((input_clock_khz * 13 / 10000)+1, /* fast speed low, 1.3us */
dev->base + DW_IC_FS_SCL_LCNT);
/* configure the i2c master */
ic_con = DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE |
DW_IC_CON_RESTART_EN | DW_IC_CON_SPEED_FAST;
writew(ic_con, dev->base + DW_IC_CON);
}
/*
* Waiting for bus not busy
*/
static int i2c_dw_wait_bus_not_busy(struct dw_i2c_dev *dev)
{
int timeout = TIMEOUT;
while (readb(dev->base + DW_IC_STATUS) & DW_IC_STATUS_ACTIVITY) {
if (timeout <= 0) {
dev_warn(dev->dev, "timeout waiting for bus ready\n");
return -ETIMEDOUT;
}
timeout--;
mdelay(1);
}
return 0;
}
/*
* Initiate low level master read/write transaction.
* This function is called from i2c_dw_xfer when starting a transfer.
* This function is also called from dw_i2c_pump_msg to continue a transfer
* that is longer than the size of the TX FIFO.
*/
static void
i2c_dw_xfer_msg(struct i2c_adapter *adap)
{
struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
struct i2c_msg *msgs = dev->msgs;
int num = dev->msgs_num;
u16 ic_con, intr_mask;
int tx_limit = dev->tx_fifo_depth - readb(dev->base + DW_IC_TXFLR);
int rx_limit = dev->rx_fifo_depth - readb(dev->base + DW_IC_RXFLR);
u16 addr = msgs[dev->msg_write_idx].addr;
u16 buf_len = dev->tx_buf_len;
if (!(dev->status & STATUS_WRITE_IN_PROGRESS)) {
/* Disable the adapter */
writeb(0, dev->base + DW_IC_ENABLE);
/* set the slave (target) address */
writew(msgs[dev->msg_write_idx].addr, dev->base + DW_IC_TAR);
/* if the slave address is ten bit address, enable 10BITADDR */
ic_con = readw(dev->base + DW_IC_CON);
if (msgs[dev->msg_write_idx].flags & I2C_M_TEN)
ic_con |= DW_IC_CON_10BITADDR_MASTER;
else
ic_con &= ~DW_IC_CON_10BITADDR_MASTER;
writew(ic_con, dev->base + DW_IC_CON);
/* Enable the adapter */
writeb(1, dev->base + DW_IC_ENABLE);
}
for (; dev->msg_write_idx < num; dev->msg_write_idx++) {
/* if target address has changed, we need to
* reprogram the target address in the i2c
* adapter when we are done with this transfer
*/
if (msgs[dev->msg_write_idx].addr != addr)
return;
if (msgs[dev->msg_write_idx].len == 0) {
dev_err(dev->dev,
"%s: invalid message length\n", __func__);
dev->msg_err = -EINVAL;
return;
}
if (!(dev->status & STATUS_WRITE_IN_PROGRESS)) {
/* new i2c_msg */
dev->tx_buf = msgs[dev->msg_write_idx].buf;
buf_len = msgs[dev->msg_write_idx].len;
}
while (buf_len > 0 && tx_limit > 0 && rx_limit > 0) {
if (msgs[dev->msg_write_idx].flags & I2C_M_RD) {
writew(0x100, dev->base + DW_IC_DATA_CMD);
rx_limit--;
} else
writew(*(dev->tx_buf++),
dev->base + DW_IC_DATA_CMD);
tx_limit--; buf_len--;
}
}
intr_mask = DW_IC_INTR_STOP_DET | DW_IC_INTR_TX_ABRT;
if (buf_len > 0) { /* more bytes to be written */
intr_mask |= DW_IC_INTR_TX_EMPTY;
dev->status |= STATUS_WRITE_IN_PROGRESS;
} else
dev->status &= ~STATUS_WRITE_IN_PROGRESS;
writew(intr_mask, dev->base + DW_IC_INTR_MASK);
dev->tx_buf_len = buf_len;
}
static void
i2c_dw_read(struct i2c_adapter *adap)
{
struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
struct i2c_msg *msgs = dev->msgs;
int num = dev->msgs_num;
u16 addr = msgs[dev->msg_read_idx].addr;
int rx_valid = readw(dev->base + DW_IC_RXFLR);
for (; dev->msg_read_idx < num; dev->msg_read_idx++) {
u16 len;
u8 *buf;
if (!(msgs[dev->msg_read_idx].flags & I2C_M_RD))
continue;
/* different i2c client, reprogram the i2c adapter */
if (msgs[dev->msg_read_idx].addr != addr)
return;
if (!(dev->status & STATUS_READ_IN_PROGRESS)) {
len = msgs[dev->msg_read_idx].len;
buf = msgs[dev->msg_read_idx].buf;
} else {
len = dev->rx_buf_len;
buf = dev->rx_buf;
}
for (; len > 0 && rx_valid > 0; len--, rx_valid--)
*buf++ = readb(dev->base + DW_IC_DATA_CMD);
if (len > 0) {
dev->status |= STATUS_READ_IN_PROGRESS;
dev->rx_buf_len = len;
dev->rx_buf = buf;
return;
} else
dev->status &= ~STATUS_READ_IN_PROGRESS;
}
}
/*
* Prepare controller for a transaction and call i2c_dw_xfer_msg
*/
static int
i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
{
struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
int ret;
dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num);
mutex_lock(&dev->lock);
INIT_COMPLETION(dev->cmd_complete);
dev->msgs = msgs;
dev->msgs_num = num;
dev->cmd_err = 0;
dev->msg_write_idx = 0;
dev->msg_read_idx = 0;
dev->msg_err = 0;
dev->status = STATUS_IDLE;
ret = i2c_dw_wait_bus_not_busy(dev);
if (ret < 0)
goto done;
/* start the transfers */
i2c_dw_xfer_msg(adap);
/* wait for tx to complete */
ret = wait_for_completion_interruptible_timeout(&dev->cmd_complete, HZ);
if (ret == 0) {
dev_err(dev->dev, "controller timed out\n");
i2c_dw_init(dev);
ret = -ETIMEDOUT;
goto done;
} else if (ret < 0)
goto done;
if (dev->msg_err) {
ret = dev->msg_err;
goto done;
}
/* no error */
if (likely(!dev->cmd_err)) {
/* read rx fifo, and disable the adapter */
do {
i2c_dw_read(adap);
} while (dev->status & STATUS_READ_IN_PROGRESS);
writeb(0, dev->base + DW_IC_ENABLE);
ret = num;
goto done;
}
/* We have an error */
if (dev->cmd_err == DW_IC_ERR_TX_ABRT) {
unsigned long abort_source = dev->abort_source;
int i;
for_each_bit(i, &abort_source, ARRAY_SIZE(abort_sources)) {
dev_err(dev->dev, "%s: %s\n", __func__, abort_sources[i]);
}
}
ret = -EIO;
done:
mutex_unlock(&dev->lock);
return ret;
}
static u32 i2c_dw_func(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR;
}
static void dw_i2c_pump_msg(unsigned long data)
{
struct dw_i2c_dev *dev = (struct dw_i2c_dev *) data;
u16 intr_mask;
i2c_dw_read(&dev->adapter);
i2c_dw_xfer_msg(&dev->adapter);
intr_mask = DW_IC_INTR_STOP_DET | DW_IC_INTR_TX_ABRT;
if (dev->status & STATUS_WRITE_IN_PROGRESS)
intr_mask |= DW_IC_INTR_TX_EMPTY;
writew(intr_mask, dev->base + DW_IC_INTR_MASK);
}
/*
* Interrupt service routine. This gets called whenever an I2C interrupt
* occurs.
*/
static irqreturn_t i2c_dw_isr(int this_irq, void *dev_id)
{
struct dw_i2c_dev *dev = dev_id;
u16 stat;
stat = readw(dev->base + DW_IC_INTR_STAT);
dev_dbg(dev->dev, "%s: stat=0x%x\n", __func__, stat);
if (stat & DW_IC_INTR_TX_ABRT) {
dev->abort_source = readw(dev->base + DW_IC_TX_ABRT_SOURCE);
dev->cmd_err |= DW_IC_ERR_TX_ABRT;
dev->status = STATUS_IDLE;
} else if (stat & DW_IC_INTR_TX_EMPTY)
tasklet_schedule(&dev->pump_msg);
readb(dev->base + DW_IC_CLR_INTR); /* clear interrupts */
writew(0, dev->base + DW_IC_INTR_MASK); /* disable interrupts */
if (stat & (DW_IC_INTR_TX_ABRT | DW_IC_INTR_STOP_DET))
complete(&dev->cmd_complete);
return IRQ_HANDLED;
}
static struct i2c_algorithm i2c_dw_algo = {
.master_xfer = i2c_dw_xfer,
.functionality = i2c_dw_func,
};
static int __devinit dw_i2c_probe(struct platform_device *pdev)
{
struct dw_i2c_dev *dev;
struct i2c_adapter *adap;
struct resource *mem, *irq, *ioarea;
int r;
/* NOTE: driver uses the static register mapping */
mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!mem) {
dev_err(&pdev->dev, "no mem resource?\n");
return -EINVAL;
}
irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
if (!irq) {
dev_err(&pdev->dev, "no irq resource?\n");
return -EINVAL;
}
ioarea = request_mem_region(mem->start, resource_size(mem),
pdev->name);
if (!ioarea) {
dev_err(&pdev->dev, "I2C region already claimed\n");
return -EBUSY;
}
dev = kzalloc(sizeof(struct dw_i2c_dev), GFP_KERNEL);
if (!dev) {
r = -ENOMEM;
goto err_release_region;
}
init_completion(&dev->cmd_complete);
tasklet_init(&dev->pump_msg, dw_i2c_pump_msg, (unsigned long) dev);
mutex_init(&dev->lock);
dev->dev = get_device(&pdev->dev);
dev->irq = irq->start;
platform_set_drvdata(pdev, dev);
dev->clk = clk_get(&pdev->dev, NULL);
if (IS_ERR(dev->clk)) {
r = -ENODEV;
goto err_free_mem;
}
clk_enable(dev->clk);
dev->base = ioremap(mem->start, resource_size(mem));
if (dev->base == NULL) {
dev_err(&pdev->dev, "failure mapping io resources\n");
r = -EBUSY;
goto err_unuse_clocks;
}
{
u32 param1 = readl(dev->base + DW_IC_COMP_PARAM_1);
dev->tx_fifo_depth = ((param1 >> 16) & 0xff) + 1;
dev->rx_fifo_depth = ((param1 >> 8) & 0xff) + 1;
}
i2c_dw_init(dev);
writew(0, dev->base + DW_IC_INTR_MASK); /* disable IRQ */
r = request_irq(dev->irq, i2c_dw_isr, 0, pdev->name, dev);
if (r) {
dev_err(&pdev->dev, "failure requesting irq %i\n", dev->irq);
goto err_iounmap;
}
adap = &dev->adapter;
i2c_set_adapdata(adap, dev);
adap->owner = THIS_MODULE;
adap->class = I2C_CLASS_HWMON;
strlcpy(adap->name, "Synopsys DesignWare I2C adapter",
sizeof(adap->name));
adap->algo = &i2c_dw_algo;
adap->dev.parent = &pdev->dev;
adap->nr = pdev->id;
r = i2c_add_numbered_adapter(adap);
if (r) {
dev_err(&pdev->dev, "failure adding adapter\n");
goto err_free_irq;
}
return 0;
err_free_irq:
free_irq(dev->irq, dev);
err_iounmap:
iounmap(dev->base);
err_unuse_clocks:
clk_disable(dev->clk);
clk_put(dev->clk);
dev->clk = NULL;
err_free_mem:
platform_set_drvdata(pdev, NULL);
put_device(&pdev->dev);
kfree(dev);
err_release_region:
release_mem_region(mem->start, resource_size(mem));
return r;
}
static int __devexit dw_i2c_remove(struct platform_device *pdev)
{
struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
struct resource *mem;
platform_set_drvdata(pdev, NULL);
i2c_del_adapter(&dev->adapter);
put_device(&pdev->dev);
clk_disable(dev->clk);
clk_put(dev->clk);
dev->clk = NULL;
writeb(0, dev->base + DW_IC_ENABLE);
free_irq(dev->irq, dev);
kfree(dev);
mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
release_mem_region(mem->start, resource_size(mem));
return 0;
}
/* work with hotplug and coldplug */
MODULE_ALIAS("platform:i2c_designware");
static struct platform_driver dw_i2c_driver = {
.remove = __devexit_p(dw_i2c_remove),
.driver = {
.name = "i2c_designware",
.owner = THIS_MODULE,
},
};
static int __init dw_i2c_init_driver(void)
{
return platform_driver_probe(&dw_i2c_driver, dw_i2c_probe);
}
module_init(dw_i2c_init_driver);
static void __exit dw_i2c_exit_driver(void)
{
platform_driver_unregister(&dw_i2c_driver);
}
module_exit(dw_i2c_exit_driver);
MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>");
MODULE_DESCRIPTION("Synopsys DesignWare I2C bus adapter");
MODULE_LICENSE("GPL");
