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i2c: axxia: Add bus recovery functionality 

Use recovery framework and implement bus recovery using "Bus Monitor" register.
Tests show that shortening SDA to GND results in "completion" timeout with
"BUSY" bit still set, so initiate recovery in this case.

Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Alexander Sverdlin 2015-05-13 11:03:42 +02:00 committed by Wolfram Sang
parent 7ef85f5fdd
commit 7e2dc811b4
1 changed files with 41 additions and 0 deletions
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41
drivers/i2c/busses/i2c-axxia.c
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@ -42,6 +42,10 @@
#define IBML_LOW_SEXT 0x18
#define TIMER_CLOCK_DIV 0x1c
#define I2C_BUS_MONITOR 0x20
#define BM_SDAC BIT(3)
#define BM_SCLC BIT(2)
#define BM_SDAS BIT(1)
#define BM_SCLS BIT(0)
#define SOFT_RESET 0x24
#define MST_COMMAND 0x28
#define CMD_BUSY (1<<3)
@ -394,6 +398,9 @@ static int axxia_i2c_xfer_msg(struct axxia_i2c_dev *idev, struct i2c_msg *msg)
if (time_left == 0)
idev->msg_err = -ETIMEDOUT;
if (idev->msg_err == -ETIMEDOUT)
i2c_recover_bus(&idev->adapter);
if (unlikely(idev->msg_err) && idev->msg_err != -ENXIO)
axxia_i2c_init(idev);
@ -437,6 +444,39 @@ axxia_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
return ret ? : i;
}
static int axxia_i2c_get_scl(struct i2c_adapter *adap)
{
struct axxia_i2c_dev *idev = i2c_get_adapdata(adap);
return !!(readl(idev->base + I2C_BUS_MONITOR) & BM_SCLS);
}
static void axxia_i2c_set_scl(struct i2c_adapter *adap, int val)
{
struct axxia_i2c_dev *idev = i2c_get_adapdata(adap);
u32 tmp;
/* Preserve SDA Control */
tmp = readl(idev->base + I2C_BUS_MONITOR) & BM_SDAC;
if (!val)
tmp |= BM_SCLC;
writel(tmp, idev->base + I2C_BUS_MONITOR);
}
static int axxia_i2c_get_sda(struct i2c_adapter *adap)
{
struct axxia_i2c_dev *idev = i2c_get_adapdata(adap);
return !!(readl(idev->base + I2C_BUS_MONITOR) & BM_SDAS);
}
static struct i2c_bus_recovery_info axxia_i2c_recovery_info = {
.recover_bus = i2c_generic_scl_recovery,
.get_scl = axxia_i2c_get_scl,
.set_scl = axxia_i2c_set_scl,
.get_sda = axxia_i2c_get_sda,
};
static u32 axxia_i2c_func(struct i2c_adapter *adap)
{
u32 caps = (I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR |
@ -511,6 +551,7 @@ static int axxia_i2c_probe(struct platform_device *pdev)
strlcpy(idev->adapter.name, pdev->name, sizeof(idev->adapter.name));
idev->adapter.owner = THIS_MODULE;
idev->adapter.algo = &axxia_i2c_algo;
idev->adapter.bus_recovery_info = &axxia_i2c_recovery_info;
idev->adapter.quirks = &axxia_i2c_quirks;
idev->adapter.dev.parent = &pdev->dev;
idev->adapter.dev.of_node = pdev->dev.of_node;