diff mbox series

[1/2] media: hi556: Fix reset GPIO timings

Message ID 20250531190534.94684-2-hansg@kernel.org
State New
Headers show
Series media: hi556: Fixes for x86 support | expand

Commit Message

Hans de Goede May 31, 2025, 7:05 p.m. UTC 
From: Hans de Goede <hdegoede@redhat.com>

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>
---
 drivers/media/i2c/hi556.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/drivers/media/i2c/hi556.c b/drivers/media/i2c/hi556.c
index aed258211b8a..d3cc65b67855 100644
--- 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;
 }