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    SubjectRe: [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@bp.renesas.com>
    >
    > Switch to using runtime PM for power management.
    >
    > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.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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