Hi Hans,
On Tue, Jun 27, 2023 at 03:18:15PM +0200, Hans de Goede wrote:
> On ACPI systems the following 2 scenarios are possible:
>
> 1. The xvclk is fully controlled by ACPI powermanagement, so there
> is no "xvclk" for the driver to get (since it is abstracted away).
> In this case there will be a "clock-frequency" device property
> to tell the driver the xvclk rate.
>
> 2. There is a xvclk modelled in the clk framework for the driver,
> but the clk-generator may not be set to the right frequency
> yet. In this case there will also be a "clock-frequency" device
> property and the driver is expected to set the rate of the xvclk
> through this frequency through the clk framework.
>
> Handle both these scenarios by switching to devm_clk_get_optional()
> and checking for a "clock-frequency" device property.
>
> This is modelled after how the same issue was fixed for the ov8865 in
> commit 73dcffeb2ff9 ("media: i2c: Support 19.2MHz input clock in ov8865").
>
> Acked-by: Rui Miguel Silva <rmfrfs@xxxxxxxxx>
> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
> ---
> drivers/media/i2c/ov2680.c | 26 ++++++++++++++++++++++++--
> 1 file changed, 24 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/i2c/ov2680.c b/drivers/media/i2c/ov2680.c
> index b7c23286700e..a6a83f0e53f3 100644
> --- a/drivers/media/i2c/ov2680.c
> +++ b/drivers/media/i2c/ov2680.c
> @@ -698,6 +698,7 @@ static int ov2680_parse_dt(struct ov2680_dev *sensor)
> {
> struct device *dev = sensor->dev;
> struct gpio_desc *gpio;
> + unsigned int rate = 0;
> int ret;
>
> /*
> @@ -718,13 +719,34 @@ static int ov2680_parse_dt(struct ov2680_dev *sensor)
>
> sensor->pwdn_gpio = gpio;
>
> - sensor->xvclk = devm_clk_get(dev, "xvclk");
> + sensor->xvclk = devm_clk_get_optional(dev, "xvclk");
> if (IS_ERR(sensor->xvclk)) {
> dev_err(dev, "xvclk clock missing or invalid\n");
> return PTR_ERR(sensor->xvclk);
> }
>
> - sensor->xvclk_freq = clk_get_rate(sensor->xvclk);
> + /*
> + * We could have either a 24MHz or 19.2MHz clock rate from either DT or
> + * ACPI... but we also need to support the weird IPU3 case which will
> + * have an external clock AND a clock-frequency property. Check for the
> + * clock-frequency property and if found, set that rate if we managed
> + * to acquire a clock. This should cover the ACPI case. If the system
> + * uses devicetree then the configured rate should already be set, so
> + * we can just read it.
> + */
Nice comment :)
> + ret = fwnode_property_read_u32(dev_fwnode(dev), "clock-frequency",
> + &rate);
> + if (ret && !sensor->xvclk)
> + return dev_err_probe(dev, ret, "invalid clock config\n");
> +
> + if (!ret && sensor->xvclk) {
> + ret = clk_set_rate(sensor->xvclk, rate);
> + if (ret)
> + return dev_err_probe(dev, ret,
> + "failed to set clock rate\n");
> + }
> +
> + sensor->xvclk_freq = rate ?: clk_get_rate(sensor->xvclk);
> if (sensor->xvclk_freq != OV2680_XVCLK_VALUE) {
> dev_err(dev, "wrong xvclk frequency %d HZ, expected: %d Hz\n",
> sensor->xvclk_freq, OV2680_XVCLK_VALUE);
Looks good to me.
Reviewed-by: Tommaso Merciai <tomm.merciai@xxxxxxxxx>
Regards,
Tommaso
> --
> 2.41.0
>
