Hi Geert,
Thank you for the patch.
On Thu, Jun 22, 2023 at 11:21:18AM +0200, Geert Uytterhoeven wrote:
> The SH-Mobile LCD Controller is part of a PM Domain on all relevant SoCs
> (clock domain on all, power domain on some). Hence it may not be
> sufficient to manage the LCDC module clock explicitly (e.g. if the
> selected clock source differs from SHMOB_DRM_CLK_BUS).
>
> Fix this by using Runtime PM instead.
>
> Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> ---
> drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c | 11 ++++++++++-
> drivers/gpu/drm/renesas/shmobile/shmob_drm_drv.c | 5 +++++
> 2 files changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c b/drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c
> index fbfd906844da490c..84dbf35025d7be63 100644
> --- a/drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c
> +++ b/drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c
> @@ -9,6 +9,7 @@
>
> #include <linux/backlight.h>
> #include <linux/clk.h>
> +#include <linux/pm_runtime.h>
>
> #include <drm/drm_crtc.h>
> #include <drm/drm_crtc_helper.h>
> @@ -170,10 +171,16 @@ static void shmob_drm_crtc_start(struct shmob_drm_crtc *scrtc)
> if (WARN_ON(format == NULL))
> return;
>
> + ret = pm_runtime_resume_and_get(sdev->dev);
> + if (ret)
> + return;
> +
> /* Enable clocks before accessing the hardware. */
> ret = shmob_drm_clk_on(sdev);
This would be best located in the runtime PM resume handler. Same for
disabling clocks in the runtime PM suspend handler.
> - if (ret < 0)
> + if (ret < 0) {
> + pm_runtime_put(sdev->dev);
> return;
> + }
>
> /* Reset and enable the LCDC. */
> lcdc_write(sdev, LDCNT2R, lcdc_read(sdev, LDCNT2R) | LDCNT2R_BR);
> @@ -271,6 +278,8 @@ static void shmob_drm_crtc_stop(struct shmob_drm_crtc *scrtc)
> /* Stop clocks. */
> shmob_drm_clk_off(sdev);
>
> + pm_runtime_put(sdev->dev);
> +
> scrtc->started = false;
> }
>
> diff --git a/drivers/gpu/drm/renesas/shmobile/shmob_drm_drv.c b/drivers/gpu/drm/renesas/shmobile/shmob_drm_drv.c
> index 30493ce874192e3e..4f01caa119637032 100644
> --- a/drivers/gpu/drm/renesas/shmobile/shmob_drm_drv.c
> +++ b/drivers/gpu/drm/renesas/shmobile/shmob_drm_drv.c
> @@ -13,6 +13,7 @@
> #include <linux/module.h>
> #include <linux/platform_device.h>
> #include <linux/pm.h>
> +#include <linux/pm_runtime.h>
> #include <linux/slab.h>
>
> #include <drm/drm_drv.h>
> @@ -216,6 +217,10 @@ static int shmob_drm_probe(struct platform_device *pdev)
> if (IS_ERR(sdev->mmio))
> return PTR_ERR(sdev->mmio);
>
> + ret = devm_pm_runtime_enable(&pdev->dev);
> + if (ret)
> + return ret;
> +
I would move this after shmob_drm_setup_clocks(), to ensure that the
runtime PM suspend and resume handlers will have access to clocks.
> ret = shmob_drm_setup_clocks(sdev, pdata->clk_source);
> if (ret < 0)
> return ret;
--
Regards,
Laurent Pinchart
