Re: [PATCH v3 2/3] drm/rockchip: dsi: Add dphy_get_timing support for multiple PHY types

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Missing `dphy_get_timing` callback initialization in `rk3506_chip_data` causes a NULL pointer dereference on the RK3506 platform.
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--- Patch [2]: [PATCH v3 2/3] drm/rockchip: dsi: Add dphy_get_timing support for multiple PHY types ---
commit 266dcada14f6495a40e461eefa6793e6e1dcb8ca
Author: Chaoyi Chen <chaoyi.chen@rock-chips.com>

drm/rockchip: dsi: Add dphy_get_timing support for multiple PHY types

This commit introduces platform-specific D-PHY timing callbacks to handle
timing differences between older and newer Rockchip platforms.

> diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c
> index fd91343d0f6d5..557708bc4faa4 100644
> --- a/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c
> +++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c
[ ... ]
> @@ -737,6 +742,32 @@ dw_mipi_dsi_phy_get_timing(void *priv_data, unsigned int lane_mbps,
>  	return 0;
>  }
>  
> +static const struct dw_mipi_dsi_dphy_timing dphy_timing_px30 = {
> +	.clk_lp2hs = 0x40,
> +	.clk_hs2lp = 0x40,
> +	.data_lp2hs = 0x10,
> +	.data_hs2lp = 0x14,
> +};
> +
> +static int
> +dw_mipi_dsi_phy_px30_get_timing(struct dw_mipi_dsi_rockchip *dsi,
> +				unsigned int lane_mbps,
> +				struct dw_mipi_dsi_dphy_timing *timing)
> +{
> +	*timing = dphy_timing_px30;
> +
> +	return 0;
> +}
> +
> +static int
> +dw_mipi_dsi_phy_get_timing(void *priv_data, unsigned int lane_mbps,
> +			   struct dw_mipi_dsi_dphy_timing *timing)
> +{
> +	struct dw_mipi_dsi_rockchip *dsi = priv_data;
> +
> +	return dsi->cdata->dphy_get_timing(dsi, lane_mbps, timing);

[Severity: High]
Will this cause a NULL pointer dereference on the RK3506 platform?

The patch updates multiple platform definitions to set the .dphy_get_timing
callback, but it appears to have missed rk3506_chip_data, leaving its
callback as NULL.

When dw_mipi_dsi_phy_get_timing() is called during modeset on RK3506, it
unconditionally dereferences dsi->cdata->dphy_get_timing, which will lead
to an immediate crash.

Should a NULL check be added here, or should rk3506_chip_data be updated to
include a timing callback?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260810034139.148-1-kernel@airkyi.com?part=2