Re: [PATCH v1 2/4] mtk-mdp: use pm_runtime in MDP component driver

Enric Balletbo i Serra
2021-05-14T08:28:09Z

Hi Eizan,

Thank you for your patch.

On 23/4/21 7:58, Eizan Miyamoto wrote:
> Without this change, the MDP components are not fully integrated into
> the runtime power management subsystem, and the MDP driver does not
> work.
>
> For each of the component device drivers to be able to call
> pm_runtime_get/put_sync() a pointer to the component's device struct
> had to be added to struct mtk_mdp_comp, set by mtk_mdp_comp_init().
>
> Note that the dev argument to mtk_mdp_comp_clock_on/off() has been
> removed. Those functions used to be called from the "master" mdp driver
> in mtk_mdp_core.c, but the component's device pointer no longer
> corresponds to the mdp master device pointer, which is not the right
> device to pass to pm_runtime_put/get_sync() which we had to add to get
> the driver to work properly.
>
> Signed-off-by: Eizan Miyamoto <eizan@chromium.org>
> ---
>
> drivers/media/platform/mtk-mdp/mtk_mdp_comp.c | 19 ++++++++++++++++---
> drivers/media/platform/mtk-mdp/mtk_mdp_comp.h | 6 ++++--
> drivers/media/platform/mtk-mdp/mtk_mdp_core.c | 6 ++----
> 3 files changed, 22 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c b/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c
> index 3fbbcf05440a..84f9c529d74a 100644
> --- a/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c
> +++ b/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c
> @@ -13,6 +13,8 @@
> #include <linux/of.h>
> #include <linux/of_irq.h>
> #include <linux/of_platform.h>
> +#include <soc/mediatek/smi.h>
> +#include <linux/pm_runtime.h>
>
> #include "mtk_mdp_comp.h"
> #include "mtk_mdp_core.h"
> @@ -51,22 +53,28 @@ static const struct of_device_id mtk_mdp_comp_driver_dt_match[] = {
> };
> MODULE_DEVICE_TABLE(of, mtk_mdp_comp_driver_dt_match);
>
> -void mtk_mdp_comp_clock_on(struct device *dev, struct mtk_mdp_comp *comp)
> +void mtk_mdp_comp_clock_on(struct mtk_mdp_comp *comp)
> {
> int i, err;
>
> + err = pm_runtime_get_sync(comp->dev);
> + if (err < 0)
> + dev_err(comp->dev,
> + "failed to runtime get, err %d.\n",
> + err);
> +

Personally, in the subsystem I take care I don't allow printing errors that are
ignored. Shouldn't you propagate the error?

> for (i = 0; i < ARRAY_SIZE(comp->clk); i++) {
> if (IS_ERR(comp->clk[i]))
> continue;
> err = clk_prepare_enable(comp->clk[i]);
> if (err)
> - dev_err(dev,
> + dev_err(comp->dev,
> "failed to enable clock, err %d. i:%d\n",
> err, i);
> }
> }
>
> -void mtk_mdp_comp_clock_off(struct device *dev, struct mtk_mdp_comp *comp)
> +void mtk_mdp_comp_clock_off(struct mtk_mdp_comp *comp)
> {
> int i;
>
> @@ -75,6 +83,8 @@ void mtk_mdp_comp_clock_off(struct device *dev, struct mtk_mdp_comp *comp)
> continue;
> clk_disable_unprepare(comp->clk[i]);
> }
> +
> + pm_runtime_put_sync(comp->dev);
> }
>
> static int mtk_mdp_comp_bind(struct device *dev, struct device *master,
> @@ -84,6 +94,7 @@ static int mtk_mdp_comp_bind(struct device *dev, struct device *master,
> struct mtk_mdp_dev *mdp = data;
>
> mtk_mdp_register_component(mdp, comp);
> + pm_runtime_enable(dev);
>
> return 0;
> }
> @@ -94,6 +105,7 @@ static void mtk_mdp_comp_unbind(struct device *dev, struct device *master,
> struct mtk_mdp_dev *mdp = data;
> struct mtk_mdp_comp *comp = dev_get_drvdata(dev);
>
> + pm_runtime_disable(dev);
> mtk_mdp_unregister_component(mdp, comp);
> }
>
> @@ -111,6 +123,7 @@ int mtk_mdp_comp_init(struct mtk_mdp_comp *comp, struct device *dev)
> (enum mtk_mdp_comp_type)of_device_get_match_data(dev);
>
> INIT_LIST_HEAD(&comp->node);
> + comp->dev = dev;
>
> for (i = 0; i < ARRAY_SIZE(comp->clk); i++) {
> comp->clk[i] = of_clk_get(node, i);
> diff --git a/drivers/media/platform/mtk-mdp/mtk_mdp_comp.h b/drivers/media/platform/mtk-mdp/mtk_mdp_comp.h
> index 956d20c01e34..355e226d74fe 100644
> --- a/drivers/media/platform/mtk-mdp/mtk_mdp_comp.h
> +++ b/drivers/media/platform/mtk-mdp/mtk_mdp_comp.h
> @@ -11,16 +11,18 @@
> * struct mtk_mdp_comp - the MDP's function component data
> * @node: list node to track sibing MDP components
> * @clk: clocks required for component
> + * @dev: component's device
> */
> struct mtk_mdp_comp {
> struct list_head node;
> struct clk *clk[2];
> + struct device *dev;
> };
>
> int mtk_mdp_comp_init(struct mtk_mdp_comp *comp, struct device *dev);
>
> -void mtk_mdp_comp_clock_on(struct device *dev, struct mtk_mdp_comp *comp);
> -void mtk_mdp_comp_clock_off(struct device *dev, struct mtk_mdp_comp *comp);
> +void mtk_mdp_comp_clock_on(struct mtk_mdp_comp *comp);
> +void mtk_mdp_comp_clock_off(struct mtk_mdp_comp *comp);
>
> extern struct platform_driver mtk_mdp_component_driver;
>
> diff --git a/drivers/media/platform/mtk-mdp/mtk_mdp_core.c b/drivers/media/platform/mtk-mdp/mtk_mdp_core.c
> index d79bf7f0031a..c55bcfe4cbb7 100644
> --- a/drivers/media/platform/mtk-mdp/mtk_mdp_core.c
> +++ b/drivers/media/platform/mtk-mdp/mtk_mdp_core.c
> @@ -51,20 +51,18 @@ MODULE_DEVICE_TABLE(of, mtk_mdp_of_ids);
>
> static void mtk_mdp_clock_on(struct mtk_mdp_dev *mdp)
> {
> - struct device *dev = &mdp->pdev->dev;
> struct mtk_mdp_comp *comp_node;
>
> list_for_each_entry(comp_node, &mdp->comp_list, node)
> - mtk_mdp_comp_clock_on(dev, comp_node);
> + mtk_mdp_comp_clock_on(comp_node);
> }
>
> static void mtk_mdp_clock_off(struct mtk_mdp_dev *mdp)
> {
> - struct device *dev = &mdp->pdev->dev;
> struct mtk_mdp_comp *comp_node;
>
> list_for_each_entry(comp_node, &mdp->comp_list, node)
> - mtk_mdp_comp_clock_off(dev, comp_node);
> + mtk_mdp_comp_clock_off(comp_node);
> }
>
> static void mtk_mdp_wdt_worker(struct work_struct *work)