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Date: Tue, 11 Oct 2022 08:13:50 +0000
From: Sakari Ailus <sakari.ailus@...ux.intel.com>
To: Prabhakar <prabhakar.csengg@...il.com>
Cc: Mauro Carvalho Chehab <mchehab@...nel.org>,
Laurent Pinchart <laurent.pinchart@...asonboard.com>,
Hans Verkuil <hverkuil@...all.nl>,
Shawn Tu <shawnx.tu@...el.com>,
Jacopo Mondi <jacopo@...ndi.org>,
Randy Dunlap <rdunlap@...radead.org>,
linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-renesas-soc@...r.kernel.org,
Biju Das <biju.das.jz@...renesas.com>,
Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
Subject: Re: [PATCH] media: i2c: ov5645: Use runtime PM
Hi Prabhakar,
Thanks for the patch. It's great to see drivers moving to runtime PM!
On Tue, Sep 27, 2022 at 09:16:34PM +0100, Prabhakar wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
>
> Switch to using runtime PM for power management.
>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> ---
> drivers/media/i2c/Kconfig | 2 +-
> drivers/media/i2c/ov5645.c | 135 +++++++++++++++++++------------------
> 2 files changed, 69 insertions(+), 68 deletions(-)
>
> diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
> index 7806d4b81716..c0edd1017fe8 100644
> --- a/drivers/media/i2c/Kconfig
> +++ b/drivers/media/i2c/Kconfig
> @@ -459,7 +459,7 @@ config VIDEO_OV5640
> config VIDEO_OV5645
> tristate "OmniVision OV5645 sensor support"
> depends on OF
> - depends on I2C && VIDEO_DEV
> + depends on I2C && PM && VIDEO_DEV
> select MEDIA_CONTROLLER
> select VIDEO_V4L2_SUBDEV_API
> select V4L2_FWNODE
> diff --git a/drivers/media/i2c/ov5645.c b/drivers/media/i2c/ov5645.c
> index 81e4e87e1821..3c3b30338328 100644
> --- a/drivers/media/i2c/ov5645.c
> +++ b/drivers/media/i2c/ov5645.c
> @@ -27,6 +27,7 @@
> #include <linux/module.h>
> #include <linux/of.h>
> #include <linux/of_graph.h>
> +#include <linux/pm_runtime.h>
> #include <linux/regulator/consumer.h>
> #include <linux/slab.h>
> #include <linux/types.h>
> @@ -108,7 +109,6 @@ struct ov5645 {
> u8 timing_tc_reg21;
>
> struct mutex power_lock; /* lock to protect power state */
> - int power_count;
>
> struct gpio_desc *enable_gpio;
> struct gpio_desc *rst_gpio;
> @@ -635,8 +635,24 @@ static int ov5645_set_register_array(struct ov5645 *ov5645,
> return 0;
> }
>
> -static int ov5645_set_power_on(struct ov5645 *ov5645)
> +static int ov5645_set_power_off(struct device *dev)
> {
> + struct v4l2_subdev *sd = dev_get_drvdata(dev);
> + struct ov5645 *ov5645 = to_ov5645(sd);
> +
> + ov5645_write_reg(ov5645, OV5645_IO_MIPI_CTRL00, 0x58);
> + gpiod_set_value_cansleep(ov5645->rst_gpio, 1);
> + gpiod_set_value_cansleep(ov5645->enable_gpio, 0);
> + clk_disable_unprepare(ov5645->xclk);
> + regulator_bulk_disable(OV5645_NUM_SUPPLIES, ov5645->supplies);
> +
> + return 0;
> +}
> +
> +static int ov5645_set_power_on(struct device *dev)
> +{
> + struct v4l2_subdev *sd = dev_get_drvdata(dev);
> + struct ov5645 *ov5645 = to_ov5645(sd);
> int ret;
>
> ret = regulator_bulk_enable(OV5645_NUM_SUPPLIES, ov5645->supplies);
> @@ -658,57 +674,19 @@ static int ov5645_set_power_on(struct ov5645 *ov5645)
>
> msleep(20);
>
> - return 0;
> -}
> -
> -static void ov5645_set_power_off(struct ov5645 *ov5645)
> -{
> - gpiod_set_value_cansleep(ov5645->rst_gpio, 1);
> - gpiod_set_value_cansleep(ov5645->enable_gpio, 0);
> - clk_disable_unprepare(ov5645->xclk);
> - regulator_bulk_disable(OV5645_NUM_SUPPLIES, ov5645->supplies);
> -}
> -
> -static int ov5645_s_power(struct v4l2_subdev *sd, int on)
> -{
> - struct ov5645 *ov5645 = to_ov5645(sd);
> - int ret = 0;
> -
> - mutex_lock(&ov5645->power_lock);
> -
> - /* If the power count is modified from 0 to != 0 or from != 0 to 0,
> - * update the power state.
> - */
> - if (ov5645->power_count == !on) {
> - if (on) {
> - ret = ov5645_set_power_on(ov5645);
> - if (ret < 0)
> - goto exit;
> -
> - ret = ov5645_set_register_array(ov5645,
> - ov5645_global_init_setting,
> + ret = ov5645_set_register_array(ov5645, ov5645_global_init_setting,
> ARRAY_SIZE(ov5645_global_init_setting));
> - if (ret < 0) {
> - dev_err(ov5645->dev,
> - "could not set init registers\n");
> - ov5645_set_power_off(ov5645);
> - goto exit;
> - }
> -
> - usleep_range(500, 1000);
> - } else {
> - ov5645_write_reg(ov5645, OV5645_IO_MIPI_CTRL00, 0x58);
> - ov5645_set_power_off(ov5645);
> - }
> + if (ret < 0) {
> + dev_err(ov5645->dev, "could not set init registers\n");
> + goto exit;
> }
>
> - /* Update the power count. */
> - ov5645->power_count += on ? 1 : -1;
> - WARN_ON(ov5645->power_count < 0);
> + usleep_range(500, 1000);
>
> -exit:
> - mutex_unlock(&ov5645->power_lock);
> + return 0;
>
> +exit:
> + ov5645_set_power_off(dev);
> return ret;
> }
>
> @@ -795,7 +773,7 @@ static int ov5645_s_ctrl(struct v4l2_ctrl *ctrl)
> int ret;
>
> mutex_lock(&ov5645->power_lock);
> - if (!ov5645->power_count) {
> + if (!pm_runtime_get_if_in_use(ov5645->dev)) {
> mutex_unlock(&ov5645->power_lock);
> return 0;
> }
> @@ -827,6 +805,7 @@ static int ov5645_s_ctrl(struct v4l2_ctrl *ctrl)
> break;
> }
>
> + pm_runtime_put_autosuspend(ov5645->dev);
> mutex_unlock(&ov5645->power_lock);
>
> return ret;
> @@ -991,6 +970,10 @@ static int ov5645_s_stream(struct v4l2_subdev *subdev, int enable)
> int ret;
>
> if (enable) {
> + ret = pm_runtime_resume_and_get(ov5645->dev);
> + if (ret < 0)
> + return ret;
> +
> ret = ov5645_set_register_array(ov5645,
> ov5645->current_mode->data,
> ov5645->current_mode->data_size);
> @@ -998,22 +981,22 @@ static int ov5645_s_stream(struct v4l2_subdev *subdev, int enable)
> dev_err(ov5645->dev, "could not set mode %dx%d\n",
> ov5645->current_mode->width,
> ov5645->current_mode->height);
> - return ret;
> + goto err_rpm_put;
> }
> ret = v4l2_ctrl_handler_setup(&ov5645->ctrls);
> if (ret < 0) {
> dev_err(ov5645->dev, "could not sync v4l2 controls\n");
> - return ret;
> + goto err_rpm_put;
> }
>
> ret = ov5645_write_reg(ov5645, OV5645_IO_MIPI_CTRL00, 0x45);
> if (ret < 0)
> - return ret;
> + goto err_rpm_put;
>
> ret = ov5645_write_reg(ov5645, OV5645_SYSTEM_CTRL0,
> OV5645_SYSTEM_CTRL0_START);
> if (ret < 0)
> - return ret;
> + goto err_rpm_put;
> } else {
> ret = ov5645_write_reg(ov5645, OV5645_IO_MIPI_CTRL00, 0x40);
> if (ret < 0)
> @@ -1023,14 +1006,15 @@ static int ov5645_s_stream(struct v4l2_subdev *subdev, int enable)
> OV5645_SYSTEM_CTRL0_STOP);
> if (ret < 0)
> return ret;
Not a problem with this patch and should be addressed separately, but the
caller will just call s_stream(0) and will ignore the return value. You
could complain about the error but still should return 0 when disabling
streaming.
> + pm_runtime_put(ov5645->dev);
> }
>
> return 0;
> -}
>
> -static const struct v4l2_subdev_core_ops ov5645_core_ops = {
> - .s_power = ov5645_s_power,
> -};
> +err_rpm_put:
> + pm_runtime_put(ov5645->dev);
> + return ret;
> +}
>
> static const struct v4l2_subdev_video_ops ov5645_video_ops = {
> .s_stream = ov5645_s_stream,
> @@ -1046,7 +1030,6 @@ static const struct v4l2_subdev_pad_ops ov5645_subdev_pad_ops = {
> };
>
> static const struct v4l2_subdev_ops ov5645_subdev_ops = {
> - .core = &ov5645_core_ops,
> .video = &ov5645_video_ops,
> .pad = &ov5645_subdev_pad_ops,
> };
> @@ -1188,11 +1171,9 @@ static int ov5645_probe(struct i2c_client *client)
> goto free_ctrl;
> }
>
> - ret = ov5645_s_power(&ov5645->sd, true);
> - if (ret < 0) {
> - dev_err(dev, "could not power up OV5645\n");
> + ret = ov5645_set_power_on(dev);
> + if (ret)
> goto free_entity;
> - }
>
> ret = ov5645_read_reg(ov5645, OV5645_CHIP_ID_HIGH, &chip_id_high);
> if (ret < 0 || chip_id_high != OV5645_CHIP_ID_HIGH_BYTE) {
> @@ -1209,12 +1190,16 @@ static int ov5645_probe(struct i2c_client *client)
>
> dev_info(dev, "OV5645 detected at address 0x%02x\n", client->addr);
>
> + pm_runtime_set_active(dev);
> + pm_runtime_get_noresume(dev);
> + pm_runtime_enable(dev);
> +
> ret = ov5645_read_reg(ov5645, OV5645_AEC_PK_MANUAL,
> &ov5645->aec_pk_manual);
> if (ret < 0) {
> dev_err(dev, "could not read AEC/AGC mode\n");
> ret = -ENODEV;
> - goto power_down;
> + goto err_pm_runtime;
> }
>
> ret = ov5645_read_reg(ov5645, OV5645_TIMING_TC_REG20,
> @@ -1222,7 +1207,7 @@ static int ov5645_probe(struct i2c_client *client)
> if (ret < 0) {
> dev_err(dev, "could not read vflip value\n");
> ret = -ENODEV;
> - goto power_down;
> + goto err_pm_runtime;
> }
>
> ret = ov5645_read_reg(ov5645, OV5645_TIMING_TC_REG21,
> @@ -1230,14 +1215,18 @@ static int ov5645_probe(struct i2c_client *client)
> if (ret < 0) {
> dev_err(dev, "could not read hflip value\n");
> ret = -ENODEV;
> - goto power_down;
> + goto err_pm_runtime;
> }
>
> - ov5645_s_power(&ov5645->sd, false);
> + pm_runtime_set_autosuspend_delay(dev, 1000);
> + pm_runtime_use_autosuspend(dev);
> + pm_runtime_put_autosuspend(dev);
You can also do this after registering async subdev. That allows removing
err_pm_runtime label and the two lines below it.
>
> ret = v4l2_async_register_subdev(&ov5645->sd);
> if (ret < 0) {
> dev_err(dev, "could not register v4l2 device\n");
> + pm_runtime_disable(dev);
> + pm_runtime_set_suspended(dev);
> goto free_entity;
> }
>
> @@ -1245,8 +1234,11 @@ static int ov5645_probe(struct i2c_client *client)
Again not a problem in this patch, but ov5645_entity_init_cfg() call here
needs to be done before registering the async subdev.
This could be addressed in a separate patch. Up to you.
>
> return 0;
>
> +err_pm_runtime:
> + pm_runtime_disable(dev);
> + pm_runtime_put_noidle(dev);
> power_down:
> - ov5645_s_power(&ov5645->sd, false);
> + ov5645_set_power_off(dev);
> free_entity:
> media_entity_cleanup(&ov5645->sd.entity);
> free_ctrl:
> @@ -1264,6 +1256,10 @@ static void ov5645_remove(struct i2c_client *client)
> v4l2_async_unregister_subdev(&ov5645->sd);
> media_entity_cleanup(&ov5645->sd.entity);
> v4l2_ctrl_handler_free(&ov5645->ctrls);
> + pm_runtime_disable(ov5645->dev);
> + if (!pm_runtime_status_suspended(ov5645->dev))
> + ov5645_set_power_off(ov5645->dev);
> + pm_runtime_set_suspended(ov5645->dev);
> mutex_destroy(&ov5645->power_lock);
> }
>
> @@ -1279,10 +1275,15 @@ static const struct of_device_id ov5645_of_match[] = {
> };
> MODULE_DEVICE_TABLE(of, ov5645_of_match);
>
> +static const struct dev_pm_ops ov5645_pm_ops = {
> + SET_RUNTIME_PM_OPS(ov5645_set_power_off, ov5645_set_power_on, NULL)
> +};
> +
> static struct i2c_driver ov5645_i2c_driver = {
> .driver = {
> .of_match_table = ov5645_of_match,
> .name = "ov5645",
> + .pm = &ov5645_pm_ops,
> },
> .probe_new = ov5645_probe,
> .remove = ov5645_remove,
--
Kind regards,
Sakari Ailus
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