From: Jai Luthra j-luthra@ti.com
[ Upstream commit d7ff69139908842adf824be4f50c7e9ac5886c04 ]
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.... [2] https://www.alinx.com/public/upload/file/AN5641_User_Manual.pdf [3] https://cdn.sparkfun.com/datasheets/Sensors/LightImaging/OV5640_datasheet.pd...
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 Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/media/i2c/ov5640.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-)
diff --git a/drivers/media/i2c/ov5640.c b/drivers/media/i2c/ov5640.c index f31b096e018f2..873087e180561 100644 --- a/drivers/media/i2c/ov5640.c +++ b/drivers/media/i2c/ov5640.c @@ -2425,11 +2425,22 @@ 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);
@@ -2478,8 +2489,7 @@ 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)