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media: ov2740: Ensure proper reset sequence on probe()

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Before this commit on probe() the driver would do:

reset=1                // from probe() calling gpiod_get(GPIOD_OUT_HIGH)
reset=0                // from resume()
msleep(20)             // from resume()

So if reset was 0 before getting the GPIO the reset line would only be
driven high for a very short time and sometimes there would be errors
reading the id register afterwards.

Add a msleep(20) after getting the reset line to ensure the sensor is
properly reset:

reset=1                // from probe() calling gpiod_get(GPIOD_OUT_HIGH)
msleep(20)             // from probe()
reset=0                // from resume()
msleep(20)             // from resume()

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
This commit is contained in:
Hans de Goede 2024-05-06 15:24:38 +02:00 committed by Hans Verkuil
parent 4ff61c4ce9
commit 6983352784
1 changed files with 8 additions and 1 deletions
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9
drivers/media/i2c/ov2740.c
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@ -1333,9 +1333,16 @@ static int ov2740_probe(struct i2c_client *client)
return dev_err_probe(dev, ret, "failed to check HW configuration\n");
ov2740->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
if (IS_ERR(ov2740->reset_gpio))
if (IS_ERR(ov2740->reset_gpio)) {
return dev_err_probe(dev, PTR_ERR(ov2740->reset_gpio),
"failed to get reset GPIO\n");
} else if (ov2740->reset_gpio) {
/*
* Ensure reset is asserted for at least 20 ms before
* ov2740_resume() deasserts it.
*/
msleep(20);
}
ov2740->clk = devm_clk_get_optional(dev, "clk");
if (IS_ERR(ov2740->clk))