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    Subject[PATCH 5.12 292/700] media: i2c: rdacm21: Fix OV10640 powerup
    Date
    From: Jacopo Mondi <jacopo+renesas@jmondi.org>

    [ Upstream commit ff75332b260cd33cc19000fdb5d256d9db4470d1 ]

    The OV10640 image sensor powerdown signal is controlled by the first
    line of the OV490 GPIO pad #1, but the pad #0 identifier
    OV490_GPIO_OUTPUT_VALUE0 was erroneously used. As a result the image
    sensor powerdown signal was never asserted but was left floating and
    kept high by an internal pull-up resistor, causing sporadic failures
    during the image sensor startup phase.

    Fix this by using the correct GPIO pad identifier and wait the mandatory
    1.5 millisecond delay after the powerup lane is asserted. 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.

    While at it also fix the reset sequence, as the reset line was released
    before the powerdown one, and the line was not cycled.

    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)

    Fixes: a59f853b3b4b ("media: i2c: Add driver for RDACM21 camera module")
    Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
    Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
    Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
    Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
    Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/media/i2c/rdacm21.c | 10 ++++++++--
    1 file changed, 8 insertions(+), 2 deletions(-)

    diff --git a/drivers/media/i2c/rdacm21.c b/drivers/media/i2c/rdacm21.c
    index 179d107f494c..4b0dfd0a75e1 100644
    --- a/drivers/media/i2c/rdacm21.c
    +++ b/drivers/media/i2c/rdacm21.c
    @@ -333,13 +333,19 @@ static int ov10640_initialize(struct rdacm21_device *dev)
    {
    u8 val;

    - /* Power-up OV10640 by setting RESETB and PWDNB pins high. */
    + /* Enable GPIO0#0 (reset) and GPIO1#0 (pwdn) as output lines. */
    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);
    +
    + /* Power up OV10640 and then reset it. */
    + ov490_write_reg(dev, OV490_GPIO_OUTPUT_VALUE1, OV490_SPWDN0);
    + usleep_range(1500, 3000);
    +
    + ov490_write_reg(dev, OV490_GPIO_OUTPUT_VALUE0, 0x00);
    + usleep_range(1500, 3000);
    ov490_write_reg(dev, OV490_GPIO_OUTPUT_VALUE0, OV490_GPIO0);
    - ov490_write_reg(dev, OV490_GPIO_OUTPUT_VALUE0, OV490_SPWDN0);
    usleep_range(3000, 5000);

    /* Read OV10640 ID to test communications. */
    --
    2.30.2


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