diff options
| author | Jai Luthra <j-luthra@ti.com> | 2023-01-03 15:27:36 +0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@kernel.org> | 2023-02-06 10:29:10 +0300 |
| commit | d7ff69139908842adf824be4f50c7e9ac5886c04 (patch) | |
| tree | 79aba188f9e0736fb653c172a52e44ca96792bd9 /drivers/media/i2c/ov5640.c | |
| parent | decea0a98b7ac04536c7d659f74783e8d67a06c0 (diff) | |
| download | linux-d7ff69139908842adf824be4f50c7e9ac5886c04.tar.xz | |
media: ov5640: Handle delays when no reset_gpio set
Some module manufacturers [1][2] don't expose the RESETB and PWDN pins
of the sensor directly through the 15-pin FFC connector. Instead wiring
~PWDN gpio to the sensor pins with appropriate delays.
In such cases, reset_gpio will not be available to the driver, but it
will still be toggled when the sensor is powered on, and thus we should
still honor the wait time of >= 5ms + 1ms + 20ms (see figure 2-3 in [3])
before attempting any i/o operations over SCCB.
Also, rename the function to ov5640_powerup_sequence to better match the
datasheet (section 2.7).
[1] https://digilent.com/reference/_media/reference/add-ons/pcam-5c/pcam_5c_sch.pdf
[2] https://www.alinx.com/public/upload/file/AN5641_User_Manual.pdf
[3] https://cdn.sparkfun.com/datasheets/Sensors/LightImaging/OV5640_datasheet.pdf
Fixes: 19a81c1426c1 ("[media] add Omnivision OV5640 sensor driver")
Reported-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Jai Luthra <j-luthra@ti.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Diffstat (limited to 'drivers/media/i2c/ov5640.c')
| -rw-r--r-- | drivers/media/i2c/ov5640.c | 22 |
1 files changed, 16 insertions, 6 deletions
diff --git a/drivers/media/i2c/ov5640.c b/drivers/media/i2c/ov5640.c index d82f250355ed..e1b8365fef58 100644 --- a/drivers/media/i2c/ov5640.c +++ b/drivers/media/i2c/ov5640.c @@ -2436,11 +2436,22 @@ static void ov5640_power(struct ov5640_dev *sensor, bool enable) gpiod_set_value_cansleep(sensor->pwdn_gpio, enable ? 0 : 1); } -static void ov5640_reset(struct ov5640_dev *sensor) +/* + * From section 2.7 power up sequence: + * t0 + t1 + t2 >= 5ms Delay from DOVDD stable to PWDN pull down + * t3 >= 1ms Delay from PWDN pull down to RESETB pull up + * t4 >= 20ms Delay from RESETB pull up to SCCB (i2c) stable + * + * Some modules don't expose RESETB/PWDN pins directly, instead providing a + * "PWUP" GPIO which is wired through appropriate delays and inverters to the + * pins. + * + * In such cases, this gpio should be mapped to pwdn_gpio in the driver, and we + * should still toggle the pwdn_gpio below with the appropriate delays, while + * the calls to reset_gpio will be ignored. + */ +static void ov5640_powerup_sequence(struct ov5640_dev *sensor) { - if (!sensor->reset_gpio) - return; - if (sensor->pwdn_gpio) { gpiod_set_value_cansleep(sensor->reset_gpio, 0); @@ -2489,8 +2500,7 @@ static int ov5640_set_power_on(struct ov5640_dev *sensor) goto xclk_off; } - ov5640_reset(sensor); - ov5640_power(sensor, true); + ov5640_powerup_sequence(sensor); ret = ov5640_init_slave_id(sensor); if (ret) |