Hi Jacopo,
On 16/02/2021 17:41, Jacopo Mondi wrote:
> The OV10640 image sensor reset and powerdown on signals are controlled
> by the embedded OV490 ISP. The current reset procedure does not respect
> the 1 millisecond power-up delay and releases the reset signal before
> the powerdown one.
>
> Fix the OV10640 power up sequence by releasing the powerdown signal,
> waiting the mandatory 1 millisecond power up delay and then releasing
> the reset signal. The reset delay is not characterized in the chip
> manual if not as "255 XVCLK + initialization". Wait for at least 3
> milliseconds to guarantee the SCCB bus is available.
>
> This commit fixes a sporadic start-up error triggered by a failure to
> read the OV10640 chip ID:
> rdacm21 8-0054: OV10640 ID mismatch: (0x01)
Have you done a similar initialisation rework for the RDACM21 as you do
in [03/16] of this series for the RDACM20 (or was it already better
perhaps?)
Only interested because of noting that I think the 'mismatch' check is
now gone from the RDAMC20.
>
> Signed-off-by: Jacopo Mondi <jacopo+renesas@xxxxxxxxxx>
> ---
> drivers/media/i2c/rdacm21.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/i2c/rdacm21.c b/drivers/media/i2c/rdacm21.c
> index b22a2ca5340b..c420a6b96879 100644
> --- a/drivers/media/i2c/rdacm21.c
> +++ b/drivers/media/i2c/rdacm21.c
> @@ -333,13 +333,15 @@ static int ov10640_initialize(struct rdacm21_device *dev)
> {
> u8 val;
>
> - /* Power-up OV10640 by setting RESETB and PWDNB pins high. */
> + /* Power-up OV10640 by setting PWDNB and RESETB pins high. */
> ov490_write_reg(dev, OV490_GPIO_SEL0, OV490_GPIO0);
> ov490_write_reg(dev, OV490_GPIO_SEL1, OV490_SPWDN0);
> ov490_write_reg(dev, OV490_GPIO_DIRECTION0, OV490_GPIO0);
> ov490_write_reg(dev, OV490_GPIO_DIRECTION1, OV490_SPWDN0);
> - ov490_write_reg(dev, OV490_GPIO_OUTPUT_VALUE0, OV490_GPIO0);
> +
> ov490_write_reg(dev, OV490_GPIO_OUTPUT_VALUE0, OV490_SPWDN0);
> + usleep_range(1500, 3000);
> + ov490_write_reg(dev, OV490_GPIO_OUTPUT_VALUE0, OV490_GPIO0);
> usleep_range(3000, 5000);
>
> /* Read OV10640 ID to test communications. */
>
