Re: [PATCH v7 7/8] media: qcom: camss: Account for C-PHY when calculating link frequency

[Wenmeng Liu <wenmeng.liu@oss.qualcomm.com>]

On 6/5/2026 9:14 PM, David Heidelberg via B4 Relay wrote:
> From: David Heidelberg <david@ixit.cz>
> 
> Ensure that the link frequency divider correctly accounts for C-PHY
> operation. The divider differs between D-PHY and C-PHY, as described
> in the MIPI CSI-2 specification.
> 
> For more details, see:
> https://docs.kernel.org/driver-api/media/tx-rx.html#pixel-rate
> 
> Suggested-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> Acked-by: Cory Keitz <ckeitz@amazon.com>
> Tested-by: Cory Keitz <ckeitz@amazon.com>
> Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
> Link: https://docs.kernel.org/driver-api/media/tx-rx.html#pixel-rate
> Signed-off-by: David Heidelberg <david@ixit.cz>
> ---
>   drivers/media/platform/qcom/camss/camss-csid.c   |  7 +++++--
>   drivers/media/platform/qcom/camss/camss-csiphy.c |  6 ++----
>   drivers/media/platform/qcom/camss/camss.c        | 18 +++++++++++++++---
>   drivers/media/platform/qcom/camss/camss.h        |  2 +-
>   4 files changed, 23 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/media/platform/qcom/camss/camss-csid.c b/drivers/media/platform/qcom/camss/camss-csid.c
> index bcc34ac9dd212..7415e811082da 100644
> --- a/drivers/media/platform/qcom/camss/camss-csid.c
> +++ b/drivers/media/platform/qcom/camss/camss-csid.c
> @@ -534,25 +534,28 @@ const struct csid_format_info *csid_get_fmt_entry(const struct csid_format_info
>   
>   /*
>    * csid_set_clock_rates - Calculate and set clock rates on CSID module
>    * @csiphy: CSID device
>    */
>   static int csid_set_clock_rates(struct csid_device *csid)
>   {
>   	struct device *dev = csid->camss->dev;
> +	struct csiphy_device *csiphy = &csid->camss->csiphy[csid->phy.csiphy_id];

The PHY indices are not necessarily contiguous on some platforms, such 
as Hamoa or Purwa.

For example, on Hamoa, we have csiphy0, csiphy1, csiphy2, and csiphy4. 
Using csiphy->id directly would lead to an array out-of-bounds access.

Thanks,
Wenmeng
> +	struct csiphy_lanes_cfg *lane_cfg = &csiphy->cfg.csi2->lane_cfg;
>   	const struct csid_format_info *fmt;
> +
>   	s64 link_freq;
>   	int i, j;
>   	int ret;
>