On 11/12/18 01:35, Lubomir Rintel wrote:
> This provides more power saving when the sensor is off.
>
> While at that, do the delay on power/clock enable even if the sensor driver
> itself doesn't control the GPIOs. This is required for the OLPC XO-1
> platform, that lacks the proper power/reset properties in its DT, but
> needs the delay after the sensor is clocked up.
>
> Signed-off-by: Lubomir Rintel <lkundrak@xxxxx>
> ---
> drivers/media/i2c/ov7670.c | 37 +++++++++++++++++++++----------------
> 1 file changed, 21 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/media/i2c/ov7670.c b/drivers/media/i2c/ov7670.c
> index d87f2362bf40..a3e72c62382c 100644
> --- a/drivers/media/i2c/ov7670.c
> +++ b/drivers/media/i2c/ov7670.c
> @@ -241,6 +241,7 @@ struct ov7670_info {
> struct v4l2_mbus_framefmt format;
> struct ov7670_format_struct *fmt; /* Current format */
> struct clk *clk;
> + int on;
> struct gpio_desc *resetb_gpio;
> struct gpio_desc *pwdn_gpio;
> unsigned int mbus_config; /* Media bus configuration flags */
> @@ -1610,15 +1611,26 @@ static int ov7670_s_power(struct v4l2_subdev *sd, int on)
> {
> struct ov7670_info *info = to_state(sd);
>
> + if (info->on == on)
> + return 0;
> +
> + if (on)
> + clk_prepare_enable(info->clk);
> + else
> + clk_disable_unprepare(info->clk);
> +
> if (info->pwdn_gpio)
> gpiod_set_value(info->pwdn_gpio, !on);
> if (on && info->resetb_gpio) {
> gpiod_set_value(info->resetb_gpio, 1);
> usleep_range(500, 1000);
> gpiod_set_value(info->resetb_gpio, 0);
> - usleep_range(3000, 5000);
> }
>
> + if (on && (info->pwdn_gpio || info->resetb_gpio || info->clk))
> + usleep_range(3000, 5000);
> +
> + info->on = on;
I assume that when powered off all control settings (brightness etc) are
lost. That means that when it is powered on you should call
v4l2_ctrl_handler_setup() to re-init the control-related registers.
The same might be the case with ov7670_set_fmt and the framerate functions.
Basically the state has to be preserved across power on -> off -> on
transitions.
Regards,
Hans
> return 0;
> }
>
> @@ -1817,24 +1829,20 @@ static int ov7670_probe(struct i2c_client *client,
> else
> return ret;
> }
> - if (info->clk) {
> - ret = clk_prepare_enable(info->clk);
> - if (ret)
> - return ret;
> + ret = ov7670_init_gpio(client, info);
> + if (ret)
> + return ret;
> +
> + ov7670_s_power(sd, 1);
>
> + if (info->clk) {
> info->clock_speed = clk_get_rate(info->clk) / 1000000;
> if (info->clock_speed < 10 || info->clock_speed > 48) {
> ret = -EINVAL;
> - goto clk_disable;
> + goto power_off;
> }
> }
>
> - ret = ov7670_init_gpio(client, info);
> - if (ret)
> - goto clk_disable;
> -
> - ov7670_s_power(sd, 1);
> -
> /* Make sure it's an ov7670 */
> ret = ov7670_detect(sd);
> if (ret) {
> @@ -1913,6 +1921,7 @@ static int ov7670_probe(struct i2c_client *client,
> if (ret < 0)
> goto entity_cleanup;
>
> + ov7670_s_power(sd, 0);
> return 0;
>
> entity_cleanup:
> @@ -1921,12 +1930,9 @@ static int ov7670_probe(struct i2c_client *client,
> v4l2_ctrl_handler_free(&info->hdl);
> power_off:
> ov7670_s_power(sd, 0);
> -clk_disable:
> - clk_disable_unprepare(info->clk);
> return ret;
> }
>
> -
> static int ov7670_remove(struct i2c_client *client)
> {
> struct v4l2_subdev *sd = i2c_get_clientdata(client);
> @@ -1934,7 +1940,6 @@ static int ov7670_remove(struct i2c_client *client)
>
> v4l2_async_unregister_subdev(sd);
> v4l2_ctrl_handler_free(&info->hdl);
> - clk_disable_unprepare(info->clk);
> media_entity_cleanup(&info->sd.entity);
> ov7670_s_power(sd, 0);
> return 0;
>
