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Message-ID: <7159c4e3-1059-7813-30a3-51027488442b@collabora.com>
Date: Mon, 12 Jul 2021 12:12:03 +0200
From: Enric Balletbo i Serra <enric.balletbo@...labora.com>
To: Eizan Miyamoto <eizan@...omium.org>, linux-kernel@...r.kernel.org
Cc: wenst@...omium.org, chunkuang.hu@...nel.org, yong.wu@...iatek.com,
houlong.wei@...iatek.com,
Andrew-CT Chen <andrew-ct.chen@...iatek.com>,
Matthias Brugger <matthias.bgg@...il.com>,
Mauro Carvalho Chehab <mchehab@...nel.org>,
Minghsiu Tsai <minghsiu.tsai@...iatek.com>,
linux-arm-kernel@...ts.infradead.org, linux-media@...r.kernel.org,
linux-mediatek@...ts.infradead.org
Subject: Re: [PATCH v5 2/8] mtk-mdp: use pm_runtime in MDP component driver
Hi Eizan,
Thank you for your patch.
On 9/7/21 4:23, 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@...omium.org>
> ---
>
> (no changes since v1)
>
> drivers/media/platform/mtk-mdp/mtk_mdp_comp.c | 20 ++++++++++++++-----
> drivers/media/platform/mtk-mdp/mtk_mdp_comp.h | 8 +++++---
> drivers/media/platform/mtk-mdp/mtk_mdp_core.c | 6 ++----
> 3 files changed, 22 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c b/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c
> index aec1cb5c4261..8b6158379f41 100644
> --- a/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c
> +++ b/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c
> @@ -14,6 +14,7 @@
> #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"
> @@ -52,7 +53,7 @@ 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;
>
> @@ -63,18 +64,22 @@ void mtk_mdp_comp_clock_on(struct device *dev, struct mtk_mdp_comp *comp)
> "failed to get larb, err %d.\n", err);
> }
>
> + err = pm_runtime_get_sync(comp->dev);
> + if (err < 0)
The pm_runtime_get_sync increases the device usage counter so, if it fails you
should decrease the usage with put.
Ok I see that put is called in off. I don't really like how the error handling
of all this is done, but also I think is not your problem, it was also a problem
before this patch.
> + dev_err(comp->dev,
> + "failed to runtime get, err %d.\n",
> + err);
> +
Printing errors and not returning errors is bad design for me. But this is a
void function, so ...
> 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,
> - "failed to enable clock, err %d. i:%d\n",
> - err, i);
> + dev_err(comp->dev, "failed to enable clock, err %d. i:%d\n", err, i);
I think that if clock fails to be enabled it will already print an error, so
this print is duplicated.
> }
> }
>
> -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;
>
> @@ -86,6 +91,8 @@ void mtk_mdp_comp_clock_off(struct device *dev, struct mtk_mdp_comp *comp)
>
> if (comp->larb_dev)
> mtk_smi_larb_put(comp->larb_dev);
> +
> + pm_runtime_put_sync(comp->dev);
> }
>
> static int mtk_mdp_comp_bind(struct device *dev, struct device *master,
> @@ -95,6 +102,7 @@ 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;
> }
> @@ -105,6 +113,7 @@ 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);
> }
>
> @@ -124,6 +133,7 @@ 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 b5a18fe567aa..5e2ee94a1b37 100644
> --- a/drivers/media/platform/mtk-mdp/mtk_mdp_comp.h
> +++ b/drivers/media/platform/mtk-mdp/mtk_mdp_comp.h
> @@ -12,17 +12,19 @@
> * @node: list node to track sibing MDP components
> * @clk: clocks required for component
> * @larb_dev: SMI device required for component
> + * @dev: component's device
> */
> struct mtk_mdp_comp {
> struct list_head node;
> struct clk *clk[2];
> - struct device *larb_dev;
> + struct device *larb_dev;
This change is unrelated to this patch.
> + 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 aca236dbd348..78c40a61df1d 100644
> --- a/drivers/media/platform/mtk-mdp/mtk_mdp_core.c
> +++ b/drivers/media/platform/mtk-mdp/mtk_mdp_core.c
> @@ -52,20 +52,18 @@ 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)
>
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