Re: [PATCH 16/19] media: i2c: ds90ub960: Enable SSCG for UB9702
From: Sakari Ailus
Date: Wed Jan 15 2025 - 09:27:11 EST
Moi,
On Fri, Jan 10, 2025 at 11:14:16AM +0200, Tomi Valkeinen wrote:
> From: Jai Luthra <jai.luthra@xxxxxxxxxxxxxxxx>
>
> UB9702 supports spread-spectrum clock generation for the back-channel
> clock, which is futher used by serializers in synchronous mode to
> generate the forward-channel clock, which can help reduce peak EMI
> energy. The SSCG is common to all RX ports, so it can only be used if
> all the ports are in the same mode.
>
> Add basic support for SSCG by adding a module parameter to enable the
> SSCG. The SSCG uses hardcoded configurationg, with 0.5% center-spread at
> 33kHz modulation rate. See datasheet if different configuration is
> required.
>
> Signed-off-by: Jai Luthra <jai.luthra@xxxxxxxxxxxxxxxx>
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx>
> ---
> drivers/media/i2c/ds90ub960.c | 102 ++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 102 insertions(+)
>
> diff --git a/drivers/media/i2c/ds90ub960.c b/drivers/media/i2c/ds90ub960.c
> index f6d6c2fe12cd..a534d077f045 100644
> --- a/drivers/media/i2c/ds90ub960.c
> +++ b/drivers/media/i2c/ds90ub960.c
> @@ -52,6 +52,10 @@
> #include <media/v4l2-fwnode.h>
> #include <media/v4l2-subdev.h>
>
> +static bool ub960_enable_sscg;
> +module_param_named(enable_sscg, ub960_enable_sscg, bool, 0644);
> +MODULE_PARM_DESC(enable_sscg, "Enable SSCG (if available)");
Shouldn't this come from DT instead?
--
Terveisin,
Sakari Ailus