RE: [PATCH 16/17] drm: renesas: rz-du: mipi_dsi: Add support for LPCLK handling

[Biju Das]

Hi Prabhakar,

Thanks for the patch.

> -----Original Message-----
> From: Prabhakar <prabhakar.csengg@xxxxxxxxx>
> Sent: 30 March 2025 22:07
> Subject: [PATCH 16/17] drm: renesas: rz-du: mipi_dsi: Add support for LPCLK handling
> 
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
> 
> Introduce the `RZ_MIPI_DSI_HASLPCLK` feature flag in `rzg2l_mipi_dsi_hw_info` to indicate the need for
> LPCLK configuration.
> 
> On the RZ/V2H(P) SoC, the LPCLK clock rate influences the required DPHY register configuration,
> whereas on the RZ/G2L SoC, this clock is not present. To accommodate this difference, add an `lpclk`
> clock handle in `rzg2l_mipi_dsi` and update the probe function to conditionally acquire LPCLK if the
> SoC supports it.
> 
> Co-developed-by: Fabrizio Castro <fabrizio.castro.jz@xxxxxxxxxxx>
> Signed-off-by: Fabrizio Castro <fabrizio.castro.jz@xxxxxxxxxxx>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
> ---
>  drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c b/drivers/gpu/drm/renesas/rz-
> du/rzg2l_mipi_dsi.c
> index 2ca725a2ccaf..26ec0f5d065a 100644
> --- a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
> +++ b/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
> @@ -31,6 +31,7 @@
>  struct rzg2l_mipi_dsi;
> 
>  #define RZ_MIPI_DSI_16BPP	BIT(0)
> +#define RZ_MIPI_DSI_HASLPCLK	BIT(1)
> 
>  struct rzg2l_mipi_dsi_hw_info {
>  	int (*dphy_init)(struct rzg2l_mipi_dsi *dsi, unsigned long long hsfreq_mhz); @@ -63,6 +64,7 @@
> struct rzg2l_mipi_dsi {
>  	struct drm_bridge *next_bridge;
> 
>  	struct clk *vclk;
> +	struct clk *lpclk;
> 
>  	enum mipi_dsi_pixel_format format;
>  	unsigned int num_data_lanes;
> @@ -792,6 +794,12 @@ static int rzg2l_mipi_dsi_probe(struct platform_device *pdev)
>  	if (IS_ERR(dsi->vclk))
>  		return PTR_ERR(dsi->vclk);
> 
> +	if (dsi->info->features & RZ_MIPI_DSI_HASLPCLK) {
> +		dsi->lpclk = devm_clk_get(dsi->dev, "lpclk");

Maybe use devm_clk_get_optional and drop the check.

Cheers,
Biju

> +		if (IS_ERR(dsi->lpclk))
> +			return PTR_ERR(dsi->lpclk);
> +	}
> +
>  	if (dsi->info->has_dphy_rstc) {
>  		dsi->rstc = devm_reset_control_get_exclusive(dsi->dev, "rst");
>  		if (IS_ERR(dsi->rstc))
> --
> 2.49.0