Re: [PATCH v2 1/1] i2c: npcm: Add clock toggle recovery

From: Mukesh Kumar Savaliya
Date: Wed Mar 26 2025 - 00:44:06 EST




On 3/25/2025 2:28 AM, mohammed.0.elbadry@xxxxxxxxx wrote:
From: Tali Perry <tali.perry1@xxxxxxxxx>

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@xxxxxxxxx>
Signed-off-by: Mohammed Elbadry <mohammed.0.elbadry@xxxxxxxxx>
---
drivers/i2c/busses/i2c-npcm7xx.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
index 3ad6124be80f..78c85015d955 100644
--- a/drivers/i2c/busses/i2c-npcm7xx.c
+++ b/drivers/i2c/busses/i2c-npcm7xx.c
@@ -2043,10 +2043,14 @@ 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, attempt 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: 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));
Should combine logging into one line. First line you say they are low, second line you are printing the actual status, may be conflicting ?
+ return -ENXIO;
+ }
}
npcm_i2c_int_enable(bus, true);