mt9m114_probe() requests the reset GPIO in output low state:
sensor->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
and then almost immediately afterwards calls mt9m114_power_on() which does:
gpiod_set_value(sensor->reset, 1);
fsleep(duration);
gpiod_set_value(sensor->reset, 0);
which means that if the reset pin was high before this code runs that
it will very briefly be driven low because of passing GPIOD_OUT_LOW when
requesting the GPIO only to be driven high again possibly directly after
that. Such a very brief driving low of the reset pin may put the chip in
a confused state.
Request the GPIO in high (reset the chip) state instead to avoid this,
turning the initial gpiod_set_value() in mt9m114_power_on() into a no-op.
and the fsleep() ensures that it will stay high long enough to properly
reset the chip.
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans de Goede <johannes.goede@oss.qualcomm.com>
---
drivers/media/i2c/mt9m114.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/media/i2c/mt9m114.c b/drivers/media/i2c/mt9m114.c
index b588b9d013ca8b41f9827cd12c0fcf56bb34bc38..8cabe04a1a64619c97edbaba09e6286b1a514604 100644
--- a/drivers/media/i2c/mt9m114.c
+++ b/drivers/media/i2c/mt9m114.c
@@ -2467,7 +2467,7 @@ static int mt9m114_probe(struct i2c_client *client)
goto error_ep_free;
}
- sensor->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
+ sensor->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
if (IS_ERR(sensor->reset)) {
ret = PTR_ERR(sensor->reset);
dev_err_probe(dev, ret, "Failed to get reset GPIO\n");
--
2.52.0