Re: [PATCH v7 3/3] media: ov8856: Implement sensor module revision identification

Marco Felsch
2020-05-05T10:17:34Z

Hi Robert,

On 20-05-05 12:01, Robert Foss wrote:
> Query the sensor for its module revision, and compare it
> to known revisions.
>
> Currently 2A and 1B revision indentification is supported.
>
> Signed-off-by: Robert Foss <robert.foss@linaro.org>
> ---
>
> - Changes since v3:
> * Actually add module revision 2A
>
> - Changes since v2:
> * Add module revision 2A
> * Sakari: Remove ov8856_check_revision()
> * Sakari: Stop EEPROM streaming mode
>
> drivers/media/i2c/ov8856.c | 53 ++++++++++++++++++++++++++++++++++++++
> 1 file changed, 53 insertions(+)
>
> diff --git a/drivers/media/i2c/ov8856.c b/drivers/media/i2c/ov8856.c
> index e6418a79801e..3c82c3e588d7 100644
> --- a/drivers/media/i2c/ov8856.c
> +++ b/drivers/media/i2c/ov8856.c
> @@ -32,6 +32,19 @@
> #define OV8856_MODE_STANDBY 0x00
> #define OV8856_MODE_STREAMING 0x01
>
> +/* module revisions */
> +#define OV8856_2A_MODULE 0x01
> +#define OV8856_1B_MODULE 0x02
> +
> +/* the OTP read-out buffer is at 0x7000 and 0xf is the offset
> + * of the byte in the OTP that means the module revision
> + */
> +#define OV8856_MODULE_REVISION 0x700f
> +#define OV8856_OTP_MODE_CTRL 0x3d84
> +#define OV8856_OTP_LOAD_CTRL 0x3d81
> +#define OV8856_OTP_MODE_AUTO 0x00
> +#define OV8856_OTP_LOAD_CTRL_ENABLE BIT(0)
> +
> /* vertical-timings from sensor */
> #define OV8856_REG_VTS 0x380e
> #define OV8856_VTS_MAX 0x7fff
> @@ -1152,6 +1165,46 @@ static int ov8856_identify_module(struct ov8856 *ov8856)
> return -ENXIO;
> }
>
> + ret = ov8856_write_reg(ov8856, OV8856_REG_MODE_SELECT,
> + OV8856_REG_VALUE_08BIT, OV8856_MODE_STREAMING);
> + if (ret)
> + return ret;
> +
> + ret = ov8856_write_reg(ov8856, OV8856_OTP_MODE_CTRL,
> + OV8856_REG_VALUE_08BIT, OV8856_OTP_MODE_AUTO);
> + if (ret) {
> + dev_err(&client->dev, "failed to set otp mode");
> + return ret;
> + }
> +
> + ret = ov8856_write_reg(ov8856, OV8856_OTP_LOAD_CTRL,
> + OV8856_REG_VALUE_08BIT,
> + OV8856_OTP_LOAD_CTRL_ENABLE);
> + if (ret) {
> + dev_err(&client->dev, "failed to enable load control");
> + return ret;
> + }
> +
> + ret = ov8856_read_reg(ov8856, OV8856_MODULE_REVISION,
> + OV8856_REG_VALUE_08BIT, &val);
> + if (ret) {
> + dev_err(&client->dev, "failed to read module revision");
> + return ret;
> + }
> +
> + dev_info(&client->dev, "OV8856 revision %x (%s) at address 0x%02x\n",
> + val,
> + val == OV8856_2A_MODULE ? "2A" :
> + val == OV8856_1B_MODULE ? "1B" : "unknown revision",
> + client->addr);

Pls check the alignment here too.

Regards,
Marco

> +
> + ret = ov8856_write_reg(ov8856, OV8856_REG_MODE_SELECT,
> + OV8856_REG_VALUE_08BIT, OV8856_MODE_STANDBY);
> + if (ret) {
> + dev_err(&client->dev, "failed to exit streaming mode");
> + return ret;
> + }
> +
> return 0;
> }
>
> --
> 2.25.1