Re: [DPU PATCH v3 4/5] drm/msm/dp: add support for DP PLL driver

[Matthias Kaehlcke <mka@chromium.org>]

On Mon, Dec 02, 2019 at 01:48:27PM +0000, Chandan Uddaraju wrote:
> Add the needed DP PLL specific files to support
> display port interface on msm targets.
> 
> The DP driver calls the DP PLL driver registration.
> The DP driver sets the link and pixel clock sources.
> 
> Changes in v2:
> -- Update copyright markings on all relevant files.
> -- Use DRM_DEBUG_DP for debug msgs.
> 
> Signed-off-by: Chandan Uddaraju <chandanu@codeaurora.org>
> ---
> diff --git a/drivers/gpu/drm/msm/dp/pll/dp_pll_10nm.c b/drivers/gpu/drm/msm/dp/pll/dp_pll_10nm.c
> new file mode 100644
> index 0000000..6ef2492
> --- /dev/null
> +++ b/drivers/gpu/drm/msm/dp/pll/dp_pll_10nm.c
>
> ...
>
> +static u8 dp_mux_get_parent_10nm(struct clk_hw *hw)
> +{
> +	u32 auxclk_div = 0;
> +	struct dp_pll_10nm_pclksel *pclksel = to_pll_10nm_pclksel(hw);
> +	struct dp_pll_10nm *dp_res = pclksel->pll;
> +	u8 val = 0;
> +
> +	DRM_ERROR("clk_hw->init->name = %s\n", hw->init->name);

drive-by comment: DRM_ERROR doesn't seem the right level, DRM_DEBUG_DP
would probably be more adequate.

Also I found this line triggers a NULL pointer dereference on a SC7180
system, where clk_hw->init is NULL.