mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-27 19:29:37 +00:00
i2c: st: Implement bus clear
>From I2C specifications: http://www.nxp.com/documents/user_manual/UM10204.pdf Chapter 3.1.16, when the i2c device held the SDA line low, the master should send 9 clocks pulses to try to recover. Signed-off-by: Frederic Pillon <frederic.pillon@st.com> Signed-off-by: Peter Griffin <peter.griffin@linaro.org> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
parent
3a9ddaf4dc
commit
40027b2fff
1 changed files with 44 additions and 1 deletions
|
@ -337,10 +337,42 @@ static void st_i2c_hw_config(struct st_i2c_dev *i2c_dev)
|
||||||
writel_relaxed(val, i2c_dev->base + SSC_NOISE_SUPP_WIDTH_DATAOUT);
|
writel_relaxed(val, i2c_dev->base + SSC_NOISE_SUPP_WIDTH_DATAOUT);
|
||||||
}
|
}
|
||||||
|
|
||||||
|
static int st_i2c_recover_bus(struct i2c_adapter *i2c_adap)
|
||||||
|
{
|
||||||
|
struct st_i2c_dev *i2c_dev = i2c_get_adapdata(i2c_adap);
|
||||||
|
u32 ctl;
|
||||||
|
|
||||||
|
dev_dbg(i2c_dev->dev, "Trying to recover bus\n");
|
||||||
|
|
||||||
|
/*
|
||||||
|
* SSP IP is dual role SPI/I2C to generate 9 clock pulses
|
||||||
|
* we switch to SPI node, 9 bit words and write a 0. This
|
||||||
|
* has been validate with a oscilloscope and is easier
|
||||||
|
* than switching to GPIO mode.
|
||||||
|
*/
|
||||||
|
|
||||||
|
/* Disable interrupts */
|
||||||
|
writel_relaxed(0, i2c_dev->base + SSC_IEN);
|
||||||
|
|
||||||
|
st_i2c_hw_config(i2c_dev);
|
||||||
|
|
||||||
|
ctl = SSC_CTL_EN | SSC_CTL_MS | SSC_CTL_EN_RX_FIFO | SSC_CTL_EN_TX_FIFO;
|
||||||
|
st_i2c_set_bits(i2c_dev->base + SSC_CTL, ctl);
|
||||||
|
|
||||||
|
st_i2c_clr_bits(i2c_dev->base + SSC_I2C, SSC_I2C_I2CM);
|
||||||
|
usleep_range(8000, 10000);
|
||||||
|
|
||||||
|
writel_relaxed(0, i2c_dev->base + SSC_TBUF);
|
||||||
|
usleep_range(2000, 4000);
|
||||||
|
st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_I2CM);
|
||||||
|
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
|
||||||
static int st_i2c_wait_free_bus(struct st_i2c_dev *i2c_dev)
|
static int st_i2c_wait_free_bus(struct st_i2c_dev *i2c_dev)
|
||||||
{
|
{
|
||||||
u32 sta;
|
u32 sta;
|
||||||
int i;
|
int i, ret;
|
||||||
|
|
||||||
for (i = 0; i < 10; i++) {
|
for (i = 0; i < 10; i++) {
|
||||||
sta = readl_relaxed(i2c_dev->base + SSC_STA);
|
sta = readl_relaxed(i2c_dev->base + SSC_STA);
|
||||||
|
@ -352,6 +384,12 @@ static int st_i2c_wait_free_bus(struct st_i2c_dev *i2c_dev)
|
||||||
|
|
||||||
dev_err(i2c_dev->dev, "bus not free (status = 0x%08x)\n", sta);
|
dev_err(i2c_dev->dev, "bus not free (status = 0x%08x)\n", sta);
|
||||||
|
|
||||||
|
ret = i2c_recover_bus(&i2c_dev->adap);
|
||||||
|
if (ret) {
|
||||||
|
dev_err(i2c_dev->dev, "Failed to recover the bus (%d)\n", ret);
|
||||||
|
return ret;
|
||||||
|
}
|
||||||
|
|
||||||
return -EBUSY;
|
return -EBUSY;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
@ -743,6 +781,10 @@ static struct i2c_algorithm st_i2c_algo = {
|
||||||
.functionality = st_i2c_func,
|
.functionality = st_i2c_func,
|
||||||
};
|
};
|
||||||
|
|
||||||
|
static struct i2c_bus_recovery_info st_i2c_recovery_info = {
|
||||||
|
.recover_bus = st_i2c_recover_bus,
|
||||||
|
};
|
||||||
|
|
||||||
static int st_i2c_of_get_deglitch(struct device_node *np,
|
static int st_i2c_of_get_deglitch(struct device_node *np,
|
||||||
struct st_i2c_dev *i2c_dev)
|
struct st_i2c_dev *i2c_dev)
|
||||||
{
|
{
|
||||||
|
@ -825,6 +867,7 @@ static int st_i2c_probe(struct platform_device *pdev)
|
||||||
adap->timeout = 2 * HZ;
|
adap->timeout = 2 * HZ;
|
||||||
adap->retries = 0;
|
adap->retries = 0;
|
||||||
adap->algo = &st_i2c_algo;
|
adap->algo = &st_i2c_algo;
|
||||||
|
adap->bus_recovery_info = &st_i2c_recovery_info;
|
||||||
adap->dev.parent = &pdev->dev;
|
adap->dev.parent = &pdev->dev;
|
||||||
adap->dev.of_node = pdev->dev.of_node;
|
adap->dev.of_node = pdev->dev.of_node;
|
||||||
|
|
||||||
|
|
Loading…
Reference in a new issue