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We should put/leave the sensor in reset when requesting the GPIO, after requesting it there are 2 possible scenarios and having the GPIO driven low is no good in either scenario: 1. The sensor was in ACPI D0 before probe() runs, in this case ov08x40_power_on() + ov08x40_identify_module() will run immediately after requesting the GPIO and ov08x40_power_on() starts with driving the GPIO high. So if the GPIO was already high it will very shortly be driven low, more of a spike to low then actually properly be driven low. Which may leave the sensor in a confused state. If we request the GPIO to be high at request time then power_on() will driver it high again (no-op) and then sleep for 1-2 ms, so no spike. 2. The sensor was in ACPI D3 / off before probe(), in this case probe() leaves the sensor alone. But when the sensor is off its reset line should be driven high not low. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Linux kernel
============
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