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linux-sg2042/drivers/i2c/busses/i2c-pnx.c

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/*
* Provides I2C support for Philips PNX010x/PNX4008 boards.
*
* Authors: Dennis Kovalev <dkovalev@ru.mvista.com>
* Vitaly Wool <vwool@ru.mvista.com>
*
* 2004-2006 (c) MontaVista Software, Inc. 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/module.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/timer.h>
#include <linux/completion.h>
#include <linux/platform_device.h>
#include <linux/i2c-pnx.h>
#include <mach/hardware.h>
#include <asm/irq.h>
#include <asm/uaccess.h>
#define I2C_PNX_TIMEOUT 10 /* msec */
#define I2C_PNX_SPEED_KHZ 100
#define I2C_PNX_REGION_SIZE 0x100
#define PNX_DEFAULT_FREQ 13 /* MHz */
static inline int wait_timeout(long timeout, struct i2c_pnx_algo_data *data)
{
while (timeout > 0 &&
(ioread32(I2C_REG_STS(data)) & mstatus_active)) {
mdelay(1);
timeout--;
}
return (timeout <= 0);
}
static inline int wait_reset(long timeout, struct i2c_pnx_algo_data *data)
{
while (timeout > 0 &&
(ioread32(I2C_REG_CTL(data)) & mcntrl_reset)) {
mdelay(1);
timeout--;
}
return (timeout <= 0);
}
static inline void i2c_pnx_arm_timer(struct i2c_adapter *adap)
{
struct i2c_pnx_algo_data *data = adap->algo_data;
struct timer_list *timer = &data->mif.timer;
int expires = I2C_PNX_TIMEOUT / (1000 / HZ);
del_timer_sync(timer);
dev_dbg(&adap->dev, "Timer armed at %lu plus %u jiffies.\n",
jiffies, expires);
timer->expires = jiffies + expires;
timer->data = (unsigned long)adap;
add_timer(timer);
}
/**
* i2c_pnx_start - start a device
* @slave_addr: slave address
* @adap: pointer to adapter structure
*
* Generate a START signal in the desired mode.
*/
static int i2c_pnx_start(unsigned char slave_addr, struct i2c_adapter *adap)
{
struct i2c_pnx_algo_data *alg_data = adap->algo_data;
dev_dbg(&adap->dev, "%s(): addr 0x%x mode %d\n", __func__,
slave_addr, alg_data->mif.mode);
/* Check for 7 bit slave addresses only */
if (slave_addr & ~0x7f) {
dev_err(&adap->dev, "%s: Invalid slave address %x. "
"Only 7-bit addresses are supported\n",
adap->name, slave_addr);
return -EINVAL;
}
/* First, make sure bus is idle */
if (wait_timeout(I2C_PNX_TIMEOUT, alg_data)) {
/* Somebody else is monopolizing the bus */
dev_err(&adap->dev, "%s: Bus busy. Slave addr = %02x, "
"cntrl = %x, stat = %x\n",
adap->name, slave_addr,
ioread32(I2C_REG_CTL(alg_data)),
ioread32(I2C_REG_STS(alg_data)));
return -EBUSY;
} else if (ioread32(I2C_REG_STS(alg_data)) & mstatus_afi) {
/* Sorry, we lost the bus */
dev_err(&adap->dev, "%s: Arbitration failure. "
"Slave addr = %02x\n", adap->name, slave_addr);
return -EIO;
}
/*
* OK, I2C is enabled and we have the bus.
* Clear the current TDI and AFI status flags.
*/
iowrite32(ioread32(I2C_REG_STS(alg_data)) | mstatus_tdi | mstatus_afi,
I2C_REG_STS(alg_data));
dev_dbg(&adap->dev, "%s(): sending %#x\n", __func__,
(slave_addr << 1) | start_bit | alg_data->mif.mode);
/* Write the slave address, START bit and R/W bit */
iowrite32((slave_addr << 1) | start_bit | alg_data->mif.mode,
I2C_REG_TX(alg_data));
dev_dbg(&adap->dev, "%s(): exit\n", __func__);
return 0;
}
/**
* i2c_pnx_stop - stop a device
* @adap: pointer to I2C adapter structure
*
* Generate a STOP signal to terminate the master transaction.
*/
static void i2c_pnx_stop(struct i2c_adapter *adap)
{
struct i2c_pnx_algo_data *alg_data = adap->algo_data;
/* Only 1 msec max timeout due to interrupt context */
long timeout = 1000;
dev_dbg(&adap->dev, "%s(): entering: stat = %04x.\n",
__func__, ioread32(I2C_REG_STS(alg_data)));
/* Write a STOP bit to TX FIFO */
iowrite32(0xff | stop_bit, I2C_REG_TX(alg_data));
/* Wait until the STOP is seen. */
while (timeout > 0 &&
(ioread32(I2C_REG_STS(alg_data)) & mstatus_active)) {
/* may be called from interrupt context */
udelay(1);
timeout--;
}
dev_dbg(&adap->dev, "%s(): exiting: stat = %04x.\n",
__func__, ioread32(I2C_REG_STS(alg_data)));
}
/**
* i2c_pnx_master_xmit - transmit data to slave
* @adap: pointer to I2C adapter structure
*
* Sends one byte of data to the slave
*/
static int i2c_pnx_master_xmit(struct i2c_adapter *adap)
{
struct i2c_pnx_algo_data *alg_data = adap->algo_data;
u32 val;
dev_dbg(&adap->dev, "%s(): entering: stat = %04x.\n",
__func__, ioread32(I2C_REG_STS(alg_data)));
if (alg_data->mif.len > 0) {
/* We still have something to talk about... */
val = *alg_data->mif.buf++;
if (alg_data->mif.len == 1) {
val |= stop_bit;
if (!alg_data->last)
val |= start_bit;
}
alg_data->mif.len--;
iowrite32(val, I2C_REG_TX(alg_data));
dev_dbg(&adap->dev, "%s(): xmit %#x [%d]\n", __func__,
val, alg_data->mif.len + 1);
if (alg_data->mif.len == 0) {
if (alg_data->last) {
/* Wait until the STOP is seen. */
if (wait_timeout(I2C_PNX_TIMEOUT, alg_data))
dev_err(&adap->dev, "The bus is still "
"active after timeout\n");
}
/* Disable master interrupts */
iowrite32(ioread32(I2C_REG_CTL(alg_data)) &
~(mcntrl_afie | mcntrl_naie | mcntrl_drmie),
I2C_REG_CTL(alg_data));
del_timer_sync(&alg_data->mif.timer);
dev_dbg(&adap->dev, "%s(): Waking up xfer routine.\n",
__func__);
complete(&alg_data->mif.complete);
}
} else if (alg_data->mif.len == 0) {
/* zero-sized transfer */
i2c_pnx_stop(adap);
/* Disable master interrupts. */
iowrite32(ioread32(I2C_REG_CTL(alg_data)) &
~(mcntrl_afie | mcntrl_naie | mcntrl_drmie),
I2C_REG_CTL(alg_data));
/* Stop timer. */
del_timer_sync(&alg_data->mif.timer);
dev_dbg(&adap->dev, "%s(): Waking up xfer routine after "
"zero-xfer.\n", __func__);
complete(&alg_data->mif.complete);
}
dev_dbg(&adap->dev, "%s(): exiting: stat = %04x.\n",
__func__, ioread32(I2C_REG_STS(alg_data)));
return 0;
}
/**
* i2c_pnx_master_rcv - receive data from slave
* @adap: pointer to I2C adapter structure
*
* Reads one byte data from the slave
*/
static int i2c_pnx_master_rcv(struct i2c_adapter *adap)
{
struct i2c_pnx_algo_data *alg_data = adap->algo_data;
unsigned int val = 0;
u32 ctl = 0;
dev_dbg(&adap->dev, "%s(): entering: stat = %04x.\n",
__func__, ioread32(I2C_REG_STS(alg_data)));
/* Check, whether there is already data,
* or we didn't 'ask' for it yet.
*/
if (ioread32(I2C_REG_STS(alg_data)) & mstatus_rfe) {
dev_dbg(&adap->dev, "%s(): Write dummy data to fill "
"Rx-fifo...\n", __func__);
if (alg_data->mif.len == 1) {
/* Last byte, do not acknowledge next rcv. */
val |= stop_bit;
if (!alg_data->last)
val |= start_bit;
/*
* Enable interrupt RFDAIE (data in Rx fifo),
* and disable DRMIE (need data for Tx)
*/
ctl = ioread32(I2C_REG_CTL(alg_data));
ctl |= mcntrl_rffie | mcntrl_daie;
ctl &= ~mcntrl_drmie;
iowrite32(ctl, I2C_REG_CTL(alg_data));
}
/*
* Now we'll 'ask' for data:
* For each byte we want to receive, we must
* write a (dummy) byte to the Tx-FIFO.
*/
iowrite32(val, I2C_REG_TX(alg_data));
return 0;
}
/* Handle data. */
if (alg_data->mif.len > 0) {
val = ioread32(I2C_REG_RX(alg_data));
*alg_data->mif.buf++ = (u8) (val & 0xff);
dev_dbg(&adap->dev, "%s(): rcv 0x%x [%d]\n", __func__, val,
alg_data->mif.len);
alg_data->mif.len--;
if (alg_data->mif.len == 0) {
if (alg_data->last)
/* Wait until the STOP is seen. */
if (wait_timeout(I2C_PNX_TIMEOUT, alg_data))
dev_err(&adap->dev, "The bus is still "
"active after timeout\n");
/* Disable master interrupts */
ctl = ioread32(I2C_REG_CTL(alg_data));
ctl &= ~(mcntrl_afie | mcntrl_naie | mcntrl_rffie |
mcntrl_drmie | mcntrl_daie);
iowrite32(ctl, I2C_REG_CTL(alg_data));
/* Kill timer. */
del_timer_sync(&alg_data->mif.timer);
complete(&alg_data->mif.complete);
}
}
dev_dbg(&adap->dev, "%s(): exiting: stat = %04x.\n",
__func__, ioread32(I2C_REG_STS(alg_data)));
return 0;
}
static irqreturn_t i2c_pnx_interrupt(int irq, void *dev_id)
{
u32 stat, ctl;
struct i2c_adapter *adap = dev_id;
struct i2c_pnx_algo_data *alg_data = adap->algo_data;
dev_dbg(&adap->dev, "%s(): mstat = %x mctrl = %x, mode = %d\n",
__func__,
ioread32(I2C_REG_STS(alg_data)),
ioread32(I2C_REG_CTL(alg_data)),
alg_data->mif.mode);
stat = ioread32(I2C_REG_STS(alg_data));
/* let's see what kind of event this is */
if (stat & mstatus_afi) {
/* We lost arbitration in the midst of a transfer */
alg_data->mif.ret = -EIO;
/* Disable master interrupts. */
ctl = ioread32(I2C_REG_CTL(alg_data));
ctl &= ~(mcntrl_afie | mcntrl_naie | mcntrl_rffie |
mcntrl_drmie);
iowrite32(ctl, I2C_REG_CTL(alg_data));
/* Stop timer, to prevent timeout. */
del_timer_sync(&alg_data->mif.timer);
complete(&alg_data->mif.complete);
} else if (stat & mstatus_nai) {
/* Slave did not acknowledge, generate a STOP */
dev_dbg(&adap->dev, "%s(): "
"Slave did not acknowledge, generating a STOP.\n",
__func__);
i2c_pnx_stop(adap);
/* Disable master interrupts. */
ctl = ioread32(I2C_REG_CTL(alg_data));
ctl &= ~(mcntrl_afie | mcntrl_naie | mcntrl_rffie |
mcntrl_drmie);
iowrite32(ctl, I2C_REG_CTL(alg_data));
/* Our return value. */
alg_data->mif.ret = -EIO;
/* Stop timer, to prevent timeout. */
del_timer_sync(&alg_data->mif.timer);
complete(&alg_data->mif.complete);
} else {
/*
* Two options:
* - Master Tx needs data.
* - There is data in the Rx-fifo
* The latter is only the case if we have requested for data,
* via a dummy write. (See 'i2c_pnx_master_rcv'.)
* We therefore check, as a sanity check, whether that interrupt
* has been enabled.
*/
if ((stat & mstatus_drmi) || !(stat & mstatus_rfe)) {
if (alg_data->mif.mode == I2C_SMBUS_WRITE) {
i2c_pnx_master_xmit(adap);
} else if (alg_data->mif.mode == I2C_SMBUS_READ) {
i2c_pnx_master_rcv(adap);
}
}
}
/* Clear TDI and AFI bits */
stat = ioread32(I2C_REG_STS(alg_data));
iowrite32(stat | mstatus_tdi | mstatus_afi, I2C_REG_STS(alg_data));
dev_dbg(&adap->dev, "%s(): exiting, stat = %x ctrl = %x.\n",
__func__, ioread32(I2C_REG_STS(alg_data)),
ioread32(I2C_REG_CTL(alg_data)));
return IRQ_HANDLED;
}
static void i2c_pnx_timeout(unsigned long data)
{
struct i2c_adapter *adap = (struct i2c_adapter *)data;
struct i2c_pnx_algo_data *alg_data = adap->algo_data;
u32 ctl;
dev_err(&adap->dev, "Master timed out. stat = %04x, cntrl = %04x. "
"Resetting master...\n",
ioread32(I2C_REG_STS(alg_data)),
ioread32(I2C_REG_CTL(alg_data)));
/* Reset master and disable interrupts */
ctl = ioread32(I2C_REG_CTL(alg_data));
ctl &= ~(mcntrl_afie | mcntrl_naie | mcntrl_rffie | mcntrl_drmie);
iowrite32(ctl, I2C_REG_CTL(alg_data));
ctl |= mcntrl_reset;
iowrite32(ctl, I2C_REG_CTL(alg_data));
wait_reset(I2C_PNX_TIMEOUT, alg_data);
alg_data->mif.ret = -EIO;
complete(&alg_data->mif.complete);
}
static inline void bus_reset_if_active(struct i2c_adapter *adap)
{
struct i2c_pnx_algo_data *alg_data = adap->algo_data;
u32 stat;
if ((stat = ioread32(I2C_REG_STS(alg_data))) & mstatus_active) {
dev_err(&adap->dev,
"%s: Bus is still active after xfer. Reset it...\n",
adap->name);
iowrite32(ioread32(I2C_REG_CTL(alg_data)) | mcntrl_reset,
I2C_REG_CTL(alg_data));
wait_reset(I2C_PNX_TIMEOUT, alg_data);
} else if (!(stat & mstatus_rfe) || !(stat & mstatus_tfe)) {
/* If there is data in the fifo's after transfer,
* flush fifo's by reset.
*/
iowrite32(ioread32(I2C_REG_CTL(alg_data)) | mcntrl_reset,
I2C_REG_CTL(alg_data));
wait_reset(I2C_PNX_TIMEOUT, alg_data);
} else if (stat & mstatus_nai) {
iowrite32(ioread32(I2C_REG_CTL(alg_data)) | mcntrl_reset,
I2C_REG_CTL(alg_data));
wait_reset(I2C_PNX_TIMEOUT, alg_data);
}
}
/**
* i2c_pnx_xfer - generic transfer entry point
* @adap: pointer to I2C adapter structure
* @msgs: array of messages
* @num: number of messages
*
* Initiates the transfer
*/
static int
i2c_pnx_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
{
struct i2c_msg *pmsg;
int rc = 0, completed = 0, i;
struct i2c_pnx_algo_data *alg_data = adap->algo_data;
u32 stat = ioread32(I2C_REG_STS(alg_data));
dev_dbg(&adap->dev, "%s(): entering: %d messages, stat = %04x.\n",
__func__, num, ioread32(I2C_REG_STS(alg_data)));
bus_reset_if_active(adap);
/* Process transactions in a loop. */
for (i = 0; rc >= 0 && i < num; i++) {
u8 addr;
pmsg = &msgs[i];
addr = pmsg->addr;
if (pmsg->flags & I2C_M_TEN) {
dev_err(&adap->dev,
"%s: 10 bits addr not supported!\n",
adap->name);
rc = -EINVAL;
break;
}
alg_data->mif.buf = pmsg->buf;
alg_data->mif.len = pmsg->len;
alg_data->mif.mode = (pmsg->flags & I2C_M_RD) ?
I2C_SMBUS_READ : I2C_SMBUS_WRITE;
alg_data->mif.ret = 0;
alg_data->last = (i == num - 1);
dev_dbg(&adap->dev, "%s(): mode %d, %d bytes\n", __func__,
alg_data->mif.mode,
alg_data->mif.len);
i2c_pnx_arm_timer(adap);
/* initialize the completion var */
init_completion(&alg_data->mif.complete);
/* Enable master interrupt */
iowrite32(ioread32(I2C_REG_CTL(alg_data)) | mcntrl_afie |
mcntrl_naie | mcntrl_drmie,
I2C_REG_CTL(alg_data));
/* Put start-code and slave-address on the bus. */
rc = i2c_pnx_start(addr, adap);
if (rc < 0)
break;
/* Wait for completion */
wait_for_completion(&alg_data->mif.complete);
if (!(rc = alg_data->mif.ret))
completed++;
dev_dbg(&adap->dev, "%s(): Complete, return code = %d.\n",
__func__, rc);
/* Clear TDI and AFI bits in case they are set. */
if ((stat = ioread32(I2C_REG_STS(alg_data))) & mstatus_tdi) {
dev_dbg(&adap->dev,
"%s: TDI still set... clearing now.\n",
adap->name);
iowrite32(stat, I2C_REG_STS(alg_data));
}
if ((stat = ioread32(I2C_REG_STS(alg_data))) & mstatus_afi) {
dev_dbg(&adap->dev,
"%s: AFI still set... clearing now.\n",
adap->name);
iowrite32(stat, I2C_REG_STS(alg_data));
}
}
bus_reset_if_active(adap);
/* Cleanup to be sure... */
alg_data->mif.buf = NULL;
alg_data->mif.len = 0;
dev_dbg(&adap->dev, "%s(): exiting, stat = %x\n",
__func__, ioread32(I2C_REG_STS(alg_data)));
if (completed != num)
return ((rc < 0) ? rc : -EREMOTEIO);
return num;
}
static u32 i2c_pnx_func(struct i2c_adapter *adapter)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}
static struct i2c_algorithm pnx_algorithm = {
.master_xfer = i2c_pnx_xfer,
.functionality = i2c_pnx_func,
};
static int i2c_pnx_controller_suspend(struct platform_device *pdev,
pm_message_t state)
{
struct i2c_pnx_data *i2c_pnx = platform_get_drvdata(pdev);
return i2c_pnx->suspend(pdev, state);
}
static int i2c_pnx_controller_resume(struct platform_device *pdev)
{
struct i2c_pnx_data *i2c_pnx = platform_get_drvdata(pdev);
return i2c_pnx->resume(pdev);
}
static int __devinit i2c_pnx_probe(struct platform_device *pdev)
{
unsigned long tmp;
int ret = 0;
struct i2c_pnx_algo_data *alg_data;
int freq_mhz;
struct i2c_pnx_data *i2c_pnx = pdev->dev.platform_data;
if (!i2c_pnx || !i2c_pnx->adapter) {
dev_err(&pdev->dev, "%s: no platform data supplied\n",
__func__);
ret = -EINVAL;
goto out;
}
platform_set_drvdata(pdev, i2c_pnx);
if (i2c_pnx->calculate_input_freq)
freq_mhz = i2c_pnx->calculate_input_freq(pdev);
else {
freq_mhz = PNX_DEFAULT_FREQ;
dev_info(&pdev->dev, "Setting bus frequency to default value: "
"%d MHz\n", freq_mhz);
}
i2c_pnx->adapter->algo = &pnx_algorithm;
alg_data = i2c_pnx->adapter->algo_data;
init_timer(&alg_data->mif.timer);
alg_data->mif.timer.function = i2c_pnx_timeout;
alg_data->mif.timer.data = (unsigned long)i2c_pnx->adapter;
/* Register I/O resource */
if (!request_region(alg_data->base, I2C_PNX_REGION_SIZE, pdev->name)) {
dev_err(&pdev->dev,
"I/O region 0x%08x for I2C already in use.\n",
alg_data->base);
ret = -ENODEV;
goto out_drvdata;
}
if (!(alg_data->ioaddr =
(u32)ioremap(alg_data->base, I2C_PNX_REGION_SIZE))) {
dev_err(&pdev->dev, "Couldn't ioremap I2C I/O region\n");
ret = -ENOMEM;
goto out_release;
}
i2c_pnx->set_clock_run(pdev);
/*
* Clock Divisor High This value is the number of system clocks
* the serial clock (SCL) will be high.
* For example, if the system clock period is 50 ns and the maximum
* desired serial period is 10000 ns (100 kHz), then CLKHI would be
* set to 0.5*(f_sys/f_i2c)-2=0.5*(20e6/100e3)-2=98. The actual value
* programmed into CLKHI will vary from this slightly due to
* variations in the output pad's rise and fall times as well as
* the deglitching filter length.
*/
tmp = ((freq_mhz * 1000) / I2C_PNX_SPEED_KHZ) / 2 - 2;
iowrite32(tmp, I2C_REG_CKH(alg_data));
iowrite32(tmp, I2C_REG_CKL(alg_data));
iowrite32(mcntrl_reset, I2C_REG_CTL(alg_data));
if (wait_reset(I2C_PNX_TIMEOUT, alg_data)) {
ret = -ENODEV;
goto out_unmap;
}
init_completion(&alg_data->mif.complete);
ret = request_irq(alg_data->irq, i2c_pnx_interrupt,
0, pdev->name, i2c_pnx->adapter);
if (ret)
goto out_clock;
/* Register this adapter with the I2C subsystem */
i2c_pnx->adapter->dev.parent = &pdev->dev;
ret = i2c_add_adapter(i2c_pnx->adapter);
if (ret < 0) {
dev_err(&pdev->dev, "I2C: Failed to add bus\n");
goto out_irq;
}
dev_dbg(&pdev->dev, "%s: Master at %#8x, irq %d.\n",
i2c_pnx->adapter->name, alg_data->base, alg_data->irq);
return 0;
out_irq:
free_irq(alg_data->irq, alg_data);
out_clock:
i2c_pnx->set_clock_stop(pdev);
out_unmap:
iounmap((void *)alg_data->ioaddr);
out_release:
release_region(alg_data->base, I2C_PNX_REGION_SIZE);
out_drvdata:
platform_set_drvdata(pdev, NULL);
out:
return ret;
}
static int __devexit i2c_pnx_remove(struct platform_device *pdev)
{
struct i2c_pnx_data *i2c_pnx = platform_get_drvdata(pdev);
struct i2c_adapter *adap = i2c_pnx->adapter;
struct i2c_pnx_algo_data *alg_data = adap->algo_data;
free_irq(alg_data->irq, alg_data);
i2c_del_adapter(adap);
i2c_pnx->set_clock_stop(pdev);
iounmap((void *)alg_data->ioaddr);
release_region(alg_data->base, I2C_PNX_REGION_SIZE);
platform_set_drvdata(pdev, NULL);
return 0;
}
static struct platform_driver i2c_pnx_driver = {
.driver = {
.name = "pnx-i2c",
.owner = THIS_MODULE,
},
.probe = i2c_pnx_probe,
.remove = __devexit_p(i2c_pnx_remove),
.suspend = i2c_pnx_controller_suspend,
.resume = i2c_pnx_controller_resume,
};
static int __init i2c_adap_pnx_init(void)
{
return platform_driver_register(&i2c_pnx_driver);
}
static void __exit i2c_adap_pnx_exit(void)
{
platform_driver_unregister(&i2c_pnx_driver);
}
MODULE_AUTHOR("Vitaly Wool, Dennis Kovalev <source@mvista.com>");
MODULE_DESCRIPTION("I2C driver for Philips IP3204-based I2C busses");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:pnx-i2c");
/* We need to make sure I2C is initialized before USB */
subsys_initcall(i2c_adap_pnx_init);
module_exit(i2c_adap_pnx_exit);
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