From: Vikram Pandita <vikram.pandita@xxxxxx>
In case a peripheral is holding the DATA bus low, provide a 400Khz
constant clock output using the TEST register.
Also soft reset the I2C controller so that there is no stale state
left in the HW state machine.
A WARN_ON() will be generated when a BB timeout happens.
Signed-off-by: Vikram Pandita <vikram.pandita@xxxxxx>
Signed-off-by: Shubhrajyoti D <shubhrajyoti@xxxxxx>
---
drivers/i2c/busses/i2c-omap.c | 15 +++++++++++++--
1 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index 2dfb631..b6fcd08 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -143,7 +143,6 @@ enum {
#define OMAP_I2C_SCLH_HSSCLH 8
/* I2C System Test Register (OMAP_I2C_SYSTEST): */
-#ifdef DEBUG
#define OMAP_I2C_SYSTEST_ST_EN (1 << 15) /* System test enable */
#define OMAP_I2C_SYSTEST_FREE (1 << 14) /* Free running mode */
#define OMAP_I2C_SYSTEST_TMODE_MASK (3 << 12) /* Test mode select */
@@ -152,7 +151,6 @@ enum {
#define OMAP_I2C_SYSTEST_SCL_O (1 << 2) /* SCL line drive out */
#define OMAP_I2C_SYSTEST_SDA_I (1 << 1) /* SDA line sense in */
#define OMAP_I2C_SYSTEST_SDA_O (1 << 0) /* SDA line drive out */
-#endif
/* OCP_SYSSTATUS bit definitions */
#define SYSS_RESETDONE_MASK (1 << 0)
@@ -641,10 +639,23 @@ omap_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
struct omap_i2c_dev *dev = i2c_get_adapdata(adap);
int i;
int r;
+ u16 val;
omap_i2c_unidle(dev);
r = omap_i2c_wait_for_bb(dev);
+ /* If timeout, try to again check after soft reset of I2C block */
+ if (WARN_ON(r == -ETIMEDOUT)) {
+ /* Provide a permanent clock to recover the peripheral */
+ val = omap_i2c_read_reg(dev, OMAP_I2C_SYSTEST_REG);
+ val |= (OMAP_I2C_SYSTEST_ST_EN |
+ OMAP_I2C_SYSTEST_FREE |
+ (2 << OMAP_I2C_SYSTEST_TMODE_SHIFT));
+ omap_i2c_write_reg(dev, OMAP_I2C_SYSTEST_REG, val);
+ msleep(1);
+ omap_i2c_init(dev);
+ r = omap_i2c_wait_for_bb(dev);
+ }
if (r < 0)
goto out;
--
1.7.1
--
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