i2c: npcm: Add clock toggle recovery

During init of the bus, the module checks that the bus is idle.
If one of the lines are stuck try to recover them first before failing.
Sometimes SDA and SCL are low if improper reset occurs (e.g., reboot).

Signed-off-by: Tali Perry <tali.perry1@gmail.com>
Signed-off-by: Mohammed Elbadry <mohammed.0.elbadry@gmail.com>
Reviewed-by: Mukesh Kumar Savaliya <quic_msavaliy@quicinc.com>
Link: https://lore.kernel.org/r/20250328193252.1570811-1-mohammed.0.elbadry@gmail.com
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>

diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
index a31d9a6677a8517151bad0735a562f3501fbf913..892e2d2988a7255b0a03bbb453ae67a05849209e 100644 (file)
--- a/drivers/i2c/busses/i2c-npcm7xx.c
+++ b/drivers/i2c/busses/i2c-npcm7xx.c
@@ -2174,10 +2174,14 @@ static int npcm_i2c_init_module(struct npcm_i2c *bus, enum i2c_mode mode,
 
        /* Check HW is OK: SDA and SCL should be high at this point. */
        if ((npcm_i2c_get_SDA(&bus->adap) == 0) || (npcm_i2c_get_SCL(&bus->adap) == 0)) {
-               dev_err(bus->dev, "I2C%d init fail: lines are low\n", bus->num);
-               dev_err(bus->dev, "SDA=%d SCL=%d\n", npcm_i2c_get_SDA(&bus->adap),
-                       npcm_i2c_get_SCL(&bus->adap));
-               return -ENXIO;
+               dev_warn(bus->dev, " I2C%d SDA=%d SCL=%d, attempting to recover\n", bus->num,
+                                npcm_i2c_get_SDA(&bus->adap), npcm_i2c_get_SCL(&bus->adap));
+               if (npcm_i2c_recovery_tgclk(&bus->adap)) {
+                       dev_err(bus->dev, "I2C%d init fail: SDA=%d SCL=%d\n",
+                               bus->num, npcm_i2c_get_SDA(&bus->adap),
+                               npcm_i2c_get_SCL(&bus->adap));
+                       return -ENXIO;
+               }
        }
 
        npcm_i2c_int_enable(bus, true);