media: hi556: Fix reset GPIO timings

[ Upstream commit 99f2211a9d89fe34b3fa847fd7a4475171406cd0 ]

probe() requests the reset GPIO to be set to high when getting it.
Immeditately after this hi556_resume() is called and sets the GPIO low.

If the GPIO was low before requesting it this will result in the GPIO
only very briefly spiking high and the sensor not being properly reset.
The same problem also happens on back to back runtime suspend + resume.

Fix this by adding a sleep of 2 ms in hi556_resume() before setting
the GPIO low (if there is a reset GPIO).

The final sleep is kept unconditional, because if there is e.g. no reset
GPIO but a controllable clock then the sensor also needs some time after
enabling the clock.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/media/i2c/hi556.c b/drivers/media/i2c/hi556.c
index 0e89aff9c664da414c6bbe439b6809953a7f1054..3c84cf07275f4cd4ec82072595293f1e2128b016 100644 (file)
--- a/drivers/media/i2c/hi556.c
+++ b/drivers/media/i2c/hi556.c
@@ -1321,7 +1321,12 @@ static int hi556_resume(struct device *dev)
                return ret;
        }
 
-       gpiod_set_value_cansleep(hi556->reset_gpio, 0);
+       if (hi556->reset_gpio) {
+               /* Assert reset for at least 2ms on back to back off-on */
+               usleep_range(2000, 2200);
+               gpiod_set_value_cansleep(hi556->reset_gpio, 0);
+       }
+
        usleep_range(5000, 5500);
        return 0;
 }