Hi Tomi,
Thank you for the patch.
On Fri, Jan 20, 2023 at 10:50:04AM +0200, Tomi Valkeinen wrote:
> Add simple runtime PM suspend and resume functionality.
I think you need to depend on PM in Kconfig. That's not a compile-time
dependency but a runtime-dependency, with runtime PM support the
suspend/resume handler will never be called.
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen+rene...@ideasonboard.com>
> ---
> drivers/gpu/drm/rcar-du/rcar_lvds.c | 43 +++++++++++++++++++++++++----
> 1 file changed, 37 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/rcar-du/rcar_lvds.c
> b/drivers/gpu/drm/rcar-du/rcar_lvds.c
> index 81a060c2fe3f..8e1be51fbee6 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_lvds.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_lvds.c
> @@ -16,6 +16,7 @@
> #include <linux/of_device.h>
> #include <linux/of_graph.h>
> #include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> #include <linux/slab.h>
> #include <linux/sys_soc.h>
>
> @@ -316,8 +317,8 @@ int rcar_lvds_pclk_enable(struct drm_bridge *bridge,
> unsigned long freq)
>
> dev_dbg(lvds->dev, "enabling LVDS PLL, freq=%luHz\n", freq);
>
> - ret = clk_prepare_enable(lvds->clocks.mod);
> - if (ret < 0)
> + ret = pm_runtime_resume_and_get(lvds->dev);
> + if (ret)
> return ret;
>
> __rcar_lvds_pll_setup_d3_e3(lvds, freq, true);
> @@ -337,7 +338,7 @@ void rcar_lvds_pclk_disable(struct drm_bridge *bridge)
>
> rcar_lvds_write(lvds, LVDPLLCR, 0);
>
> - clk_disable_unprepare(lvds->clocks.mod);
> + pm_runtime_put(lvds->dev);
Should we use pm_runtime_put_sync() here, to make sure the clock gets
disabled right away ? The DU hardware may depend on the exact sequencing
of events. I would then do the same in rcar_lvds_atomic_disable().
Reviewed-by: Laurent Pinchart <laurent.pinch...@ideasonboard.com>
> }
> EXPORT_SYMBOL_GPL(rcar_lvds_pclk_disable);
>
> @@ -396,8 +397,8 @@ static void __rcar_lvds_atomic_enable(struct drm_bridge
> *bridge,
> u32 lvdcr0;
> int ret;
>
> - ret = clk_prepare_enable(lvds->clocks.mod);
> - if (ret < 0)
> + ret = pm_runtime_resume_and_get(lvds->dev);
> + if (ret)
> return;
>
> /* Enable the companion LVDS encoder in dual-link mode. */
> @@ -551,7 +552,7 @@ static void rcar_lvds_atomic_disable(struct drm_bridge
> *bridge,
> lvds->companion->funcs->atomic_disable(lvds->companion,
> old_bridge_state);
>
> - clk_disable_unprepare(lvds->clocks.mod);
> + pm_runtime_put(lvds->dev);
> }
>
> static bool rcar_lvds_mode_fixup(struct drm_bridge *bridge,
> @@ -844,6 +845,8 @@ static int rcar_lvds_probe(struct platform_device *pdev)
> if (ret < 0)
> return ret;
>
> + pm_runtime_enable(&pdev->dev);
> +
> drm_bridge_add(&lvds->bridge);
>
> return 0;
> @@ -855,6 +858,8 @@ static int rcar_lvds_remove(struct platform_device *pdev)
>
> drm_bridge_remove(&lvds->bridge);
>
> + pm_runtime_disable(&pdev->dev);
> +
> return 0;
> }
>
> @@ -913,11 +918,37 @@ static const struct of_device_id rcar_lvds_of_table[] =
> {
>
> MODULE_DEVICE_TABLE(of, rcar_lvds_of_table);
>
> +static int rcar_lvds_runtime_suspend(struct device *dev)
> +{
> + struct rcar_lvds *lvds = dev_get_drvdata(dev);
> +
> + clk_disable_unprepare(lvds->clocks.mod);
> +
> + return 0;
> +}
> +
> +static int rcar_lvds_runtime_resume(struct device *dev)
> +{
> + struct rcar_lvds *lvds = dev_get_drvdata(dev);
> + int ret;
> +
> + ret = clk_prepare_enable(lvds->clocks.mod);
> + if (ret < 0)
> + return ret;
> +
> + return 0;
> +}
> +
> +static const struct dev_pm_ops rcar_lvds_pm_ops = {
> + SET_RUNTIME_PM_OPS(rcar_lvds_runtime_suspend, rcar_lvds_runtime_resume,
> NULL)
> +};
> +
> static struct platform_driver rcar_lvds_platform_driver = {
> .probe = rcar_lvds_probe,
> .remove = rcar_lvds_remove,
> .driver = {
> .name = "rcar-lvds",
> + .pm = &rcar_lvds_pm_ops,
> .of_match_table = rcar_lvds_of_table,
> },
> };
--
Regards,
Laurent Pinchart
