diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-omap.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-omap.c | 25 |
1 files changed, 23 insertions, 2 deletions
diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c index 12ba183693d6..a03564f41ad0 100644 --- a/drivers/i2c/busses/i2c-omap.c +++ b/drivers/i2c/busses/i2c-omap.c @@ -487,6 +487,22 @@ static int omap_i2c_init(struct omap_i2c_dev *omap) } /* + * Try bus recovery, but only if SDA is actually low. + */ +static int omap_i2c_recover_bus(struct omap_i2c_dev *omap) +{ + u16 systest; + + systest = omap_i2c_read_reg(omap, OMAP_I2C_SYSTEST_REG); + if ((systest & OMAP_I2C_SYSTEST_SCL_I_FUNC) && + (systest & OMAP_I2C_SYSTEST_SDA_I_FUNC)) + return 0; /* bus seems to already be fine */ + if (!(systest & OMAP_I2C_SYSTEST_SCL_I_FUNC)) + return -EBUSY; /* recovery would not fix SCL */ + return i2c_recover_bus(&omap->adapter); +} + +/* * Waiting on Bus Busy */ static int omap_i2c_wait_for_bb(struct omap_i2c_dev *omap) @@ -496,7 +512,7 @@ static int omap_i2c_wait_for_bb(struct omap_i2c_dev *omap) timeout = jiffies + OMAP_I2C_TIMEOUT; while (omap_i2c_read_reg(omap, OMAP_I2C_STAT_REG) & OMAP_I2C_STAT_BB) { if (time_after(jiffies, timeout)) - return i2c_recover_bus(&omap->adapter); + return omap_i2c_recover_bus(omap); msleep(1); } @@ -577,8 +593,13 @@ static int omap_i2c_wait_for_bb_valid(struct omap_i2c_dev *omap) } if (time_after(jiffies, timeout)) { + /* + * SDA or SCL were low for the entire timeout without + * any activity detected. Most likely, a slave is + * locking up the bus with no master driving the clock. + */ dev_warn(omap->dev, "timeout waiting for bus ready\n"); - return -ETIMEDOUT; + return omap_i2c_recover_bus(omap); } msleep(1); |