Re: [PATCH v4 4/9] drm: renesas: rzg2l_mipi_dsi: Add support for DSI PWRRDY

[Lad, Prabhakar]

Hi Biju,

Thank you for the patch.

On Wed, Sep 30, 2026 at 3:47 PM Biju <biju.das.au@xxxxxxxxx> wrote:
>
> From: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
>
> The register for controlling power to the DSI region is in the SYSC
> (System Controller) block. Add support for controlling the DSI PWRRDY
> signal so the driver can efficiently manage power to the DSI region.
>
> Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> ---
> v3->v4:
>  * Dropped pwrrdy variable from struct rzg2l_mipi_dsi_hw_info and instead
>    using feature flag RZ_MIPI_DSI_FEATURE_PWRRDY
>  * Dropped rzg2l_mipi_dsi_pwrrdy_off() as it is taken care by
>    devm_pwrseq_get().
> v2->v3:
>  * Updated powerseq API names.
> v1->v2:
>  * Switched to power sequence for handling pwrrdy signal.
>  * Dropped header file regmap.h and mfd/syscon.h
>  * Added header file pwrseq/consumer.h
> ---
>  .../gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c    | 27 +++++++++++++++++++
>  1 file changed, 27 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 d67e1230b70c..5263b2b8f1ca 100644
> --- a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
> +++ b/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
> @@ -18,6 +18,7 @@
>  #include <linux/of_graph.h>
>  #include <linux/platform_device.h>
>  #include <linux/pm_runtime.h>
> +#include <linux/pwrseq/consumer.h>
>  #include <linux/reset.h>
>  #include <linux/slab.h>
>  #include <linux/units.h>
> @@ -38,6 +39,7 @@ MODULE_IMPORT_NS("RZV2H_CPG");
>  #define RZG2L_DCS_BUF_SIZE     128 /* Maximum DCS buffer size in external memory. */
>
>  #define RZ_MIPI_DSI_FEATURE_16BPP      BIT(0)
> +#define RZ_MIPI_DSI_FEATURE_PWRRDY     BIT(1)
>
>  struct rzg2l_mipi_dsi;
>
> @@ -87,6 +89,8 @@ struct rzg2l_mipi_dsi {
>         struct clk *vclk;
>         struct clk *lpclk;
>
> +       struct pwrseq_desc *pwrseq;
> +
>         enum mipi_dsi_pixel_format format;
>         unsigned int num_data_lanes;
>         unsigned int lanes;
> @@ -1396,6 +1400,25 @@ static const struct dev_pm_ops rzg2l_mipi_pm_ops = {
>   * Probe & Remove
>   */
>
> +static int rzg2l_mipi_dsi_pwrrdy_init(struct rzg2l_mipi_dsi *dsi)
> +{
> +       if (!(dsi->info->features & RZ_MIPI_DSI_FEATURE_PWRRDY))
> +               return 0;
> +
> +       dsi->pwrseq = devm_pwrseq_get(dsi->dev, "dsi-pwrrdy");
> +       if (IS_ERR(dsi->pwrseq)) {
> +               /*
> +                * This platform requires a sequencer. If we can't get it, we
> +                * must return the error (including -EPROBE_DEFER to wait for
> +                * the provider to appear)
> +                */
> +               return dev_err_probe(dsi->dev, PTR_ERR(dsi->pwrseq),
> +                                    "Failed to get required power sequencer\n");
> +       }
> +
> +       return pwrseq_enable(dsi->pwrseq);
Do we want to add a devm action to disable the pwrseq when the DSI
driver is removed?

Rest LGTM.

Cheers,
Prabhakar

> +}
> +
>  static int rzg2l_mipi_dsi_probe(struct platform_device *pdev)
>  {
>         unsigned int num_data_lanes;
> @@ -1454,6 +1477,10 @@ static int rzg2l_mipi_dsi_probe(struct platform_device *pdev)
>
>         platform_set_drvdata(pdev, dsi);
>
> +       ret = rzg2l_mipi_dsi_pwrrdy_init(dsi);
> +       if (ret)
> +               return ret;
> +
>         pm_runtime_enable(dsi->dev);
>
>         ret = pm_runtime_resume_and_get(dsi->dev);
> --
> 2.43.0
>
>