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| author | Hans de Goede <hdegoede@redhat.com> | 2024-05-06 15:24:38 +0200 |
|---|---|---|
| committer | Hans Verkuil <hverkuil-cisco@xs4all.nl> | 2024-05-10 11:20:02 +0200 |
| commit | 6983352784a7b87a9c39dbbfaa33733fa1ccb0a5 (patch) | |
| tree | 48420428174ad120dfe22acecec9706c2236493c /drivers/media/i2c/ov2740.c | |
| parent | 4ff61c4ce93677cd94a0ddefbd6f3bc3c40457c4 (diff) | |
| download | lwn-6983352784a7b87a9c39dbbfaa33733fa1ccb0a5.tar.gz lwn-6983352784a7b87a9c39dbbfaa33733fa1ccb0a5.zip | |
media: ov2740: Ensure proper reset sequence on probe()
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>
Diffstat (limited to 'drivers/media/i2c/ov2740.c')
| -rw-r--r-- | drivers/media/i2c/ov2740.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/drivers/media/i2c/ov2740.c b/drivers/media/i2c/ov2740.c index 57906df7be4e..c48dbcde9877 100644 --- a/drivers/media/i2c/ov2740.c +++ b/drivers/media/i2c/ov2740.c @@ -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)) |