diff mbox series

[5/5] media: video-i2c: support runtime PM

Message ID 1537200191-17956-6-git-send-email-akinobu.mita@gmail.com (mailing list archive)
State New, archived
Headers show
Series media: video-i2c: support changing frame interval and runtime PM | expand

Commit Message

Akinobu Mita Sept. 17, 2018, 4:03 p.m. UTC
AMG88xx has a register for setting operating mode.  This adds support
runtime PM by changing the operating mode.

The instruction for changing sleep mode to normal mode is from the
reference specifications.

https://docid81hrs3j1.cloudfront.net/medialibrary/2017/11/PANA-S-A0002141979-1.pdf

Cc: Matt Ranostay <matt.ranostay@konsulko.com>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Hans Verkuil <hansverk@cisco.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
---
 drivers/media/i2c/video-i2c.c | 140 +++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 138 insertions(+), 2 deletions(-)

Comments

Matt Ranostay Sept. 18, 2018, 6:23 a.m. UTC | #1
On Mon, Sep 17, 2018 at 6:03 PM Akinobu Mita <akinobu.mita@gmail.com> wrote:
>
> AMG88xx has a register for setting operating mode.  This adds support
> runtime PM by changing the operating mode.
>
> The instruction for changing sleep mode to normal mode is from the
> reference specifications.
>
> https://docid81hrs3j1.cloudfront.net/medialibrary/2017/11/PANA-S-A0002141979-1.pdf
>
> Cc: Matt Ranostay <matt.ranostay@konsulko.com>
> Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
> Cc: Hans Verkuil <hansverk@cisco.com>
> Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
> Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
> ---
>  drivers/media/i2c/video-i2c.c | 140 +++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 138 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/i2c/video-i2c.c b/drivers/media/i2c/video-i2c.c
> index 916f36e..93822f4 100644
> --- a/drivers/media/i2c/video-i2c.c
> +++ b/drivers/media/i2c/video-i2c.c
> @@ -17,6 +17,7 @@
>  #include <linux/module.h>
>  #include <linux/mutex.h>
>  #include <linux/of_device.h>
> +#include <linux/pm_runtime.h>
>  #include <linux/regmap.h>
>  #include <linux/sched.h>
>  #include <linux/slab.h>
> @@ -94,6 +95,9 @@ struct video_i2c_chip {
>         /* xfer function */
>         int (*xfer)(struct video_i2c_data *data, char *buf);
>
> +       /* power control function */
> +       int (*set_power)(struct video_i2c_data *data, bool on);
> +
>         /* hwmon init function */
>         int (*hwmon_init)(struct video_i2c_data *data);
>  };
> @@ -104,6 +108,14 @@ static int amg88xx_xfer(struct video_i2c_data *data, char *buf)
>                                 data->chip->buffer_size);
>  }
>
> +#define AMG88XX_REG_PCTL               0x00
> +#define AMG88XX_PCTL_NORMAL            0x00
> +#define AMG88XX_PCTL_SLEEP             0x10
> +
> +#define AMG88XX_REG_RST                        0x01
> +#define AMG88XX_RST_FLAG               0x30
> +#define AMG88XX_RST_INIT               0x3f
> +
>  #define AMG88XX_REG_FPSC               0x02
>  #define AMG88XX_FPSC_1FPS              BIT(0)
>
> @@ -120,6 +132,59 @@ static int amg88xx_setup(struct video_i2c_data *data)
>         return regmap_update_bits(data->regmap, AMG88XX_REG_FPSC, mask, val);
>  }
>
> +static int amg88xx_set_power_on(struct video_i2c_data *data)
> +{
> +       int ret;
> +
> +       ret = regmap_write(data->regmap, AMG88XX_REG_PCTL, AMG88XX_PCTL_NORMAL);
> +       if (ret)
> +               return ret;
> +
> +       msleep(50);
> +
> +       ret = regmap_write(data->regmap, AMG88XX_REG_RST, AMG88XX_RST_INIT);
> +       if (ret)
> +               return ret;
> +
> +       msleep(2);
> +
> +       ret = regmap_write(data->regmap, AMG88XX_REG_RST, AMG88XX_RST_FLAG);
> +       if (ret)
> +               return ret;
> +
> +       /*
> +        * Wait two frames before reading thermistor and temperature registers
> +        */
> +       msleep(200);
> +
> +       return 0;
> +}
> +
> +static int amg88xx_set_power_off(struct video_i2c_data *data)
> +{
> +       int ret;
> +
> +       ret = regmap_write(data->regmap, AMG88XX_REG_PCTL, AMG88XX_PCTL_SLEEP);
> +       if (ret)
> +               return ret;
> +       /*
> +        * Wait for a while to avoid resuming normal mode immediately after
> +        * entering sleep mode, otherwise the device occasionally goes wrong
> +        * (thermistor and temperature registers are not updated at all)
> +        */
> +       msleep(100);
> +
> +       return 0;
> +}
> +
> +static int amg88xx_set_power(struct video_i2c_data *data, bool on)
> +{
> +       if (on)
> +               return amg88xx_set_power_on(data);
> +
> +       return amg88xx_set_power_off(data);
> +}
> +
>  #if IS_ENABLED(CONFIG_HWMON)
>
>  static const u32 amg88xx_temp_config[] = {
> @@ -151,7 +216,15 @@ static int amg88xx_read(struct device *dev, enum hwmon_sensor_types type,
>         __le16 buf;
>         int tmp;
>
> +       tmp = pm_runtime_get_sync(regmap_get_device(data->regmap));
> +       if (tmp < 0) {
> +               pm_runtime_put_noidle(regmap_get_device(data->regmap));
> +               return tmp;
> +       }
> +
>         tmp = regmap_bulk_read(data->regmap, 0x0e, &buf, 2);
> +       pm_runtime_mark_last_busy(regmap_get_device(data->regmap));
> +       pm_runtime_put_autosuspend(regmap_get_device(data->regmap));
>         if (tmp)
>                 return tmp;
>
> @@ -210,6 +283,7 @@ static const struct video_i2c_chip video_i2c_chip[] = {
>                 .regmap_config  = &amg88xx_regmap_config,
>                 .setup          = &amg88xx_setup,
>                 .xfer           = &amg88xx_xfer,
> +               .set_power      = amg88xx_set_power,
>                 .hwmon_init     = amg88xx_hwmon_init,
>         },
>  };
> @@ -336,14 +410,21 @@ static void video_i2c_del_list(struct vb2_queue *vq, enum vb2_buffer_state state
>  static int start_streaming(struct vb2_queue *vq, unsigned int count)
>  {
>         struct video_i2c_data *data = vb2_get_drv_priv(vq);
> +       struct device *dev = regmap_get_device(data->regmap);
>         int ret;
>
>         if (data->kthread_vid_cap)
>                 return 0;
>
> +       ret = pm_runtime_get_sync(dev);
> +       if (ret < 0) {
> +               pm_runtime_put_noidle(dev);
> +               goto error_del_list;
> +       }
> +
>         ret = data->chip->setup(data);
>         if (ret)
> -               goto error_del_list;
> +               goto error_rpm_put;
>
>         data->sequence = 0;
>         data->kthread_vid_cap = kthread_run(video_i2c_thread_vid_cap, data,
> @@ -352,6 +433,9 @@ static int start_streaming(struct vb2_queue *vq, unsigned int count)
>         if (!ret)
>                 return 0;
>
> +error_rpm_put:
> +       pm_runtime_mark_last_busy(dev);
> +       pm_runtime_put_autosuspend(dev);
>  error_del_list:
>         video_i2c_del_list(vq, VB2_BUF_STATE_QUEUED);
>
> @@ -367,6 +451,8 @@ static void stop_streaming(struct vb2_queue *vq)
>
>         kthread_stop(data->kthread_vid_cap);
>         data->kthread_vid_cap = NULL;
> +       pm_runtime_mark_last_busy(regmap_get_device(data->regmap));
> +       pm_runtime_put_autosuspend(regmap_get_device(data->regmap));
>
>         video_i2c_del_list(vq, VB2_BUF_STATE_ERROR);
>  }
> @@ -627,6 +713,18 @@ static int video_i2c_probe(struct i2c_client *client,
>         video_set_drvdata(&data->vdev, data);
>         i2c_set_clientdata(client, data);
>
> +       ret = data->chip->set_power(data, true);
> +       if (ret)
> +               goto error_unregister_device;
> +
> +       pm_runtime_get_noresume(&client->dev);
> +       pm_runtime_set_active(&client->dev);
> +       pm_runtime_enable(&client->dev);
> +       pm_runtime_set_autosuspend_delay(&client->dev, 2000);

2 seconds arbitrary for runtime suspending? I could be blind (or that
I can't read the part English + Japanese datasheet) but not sure how
much power is saved in low-power mode.

In any case looks fine to me.

- Matt

Reviewed-by: Matt Ranostay <matt.ranostay@konsulko.com>

> +       pm_runtime_use_autosuspend(&client->dev);
> +       pm_runtime_mark_last_busy(&client->dev);
> +       pm_runtime_put_autosuspend(&client->dev);
> +
>         if (data->chip->hwmon_init) {
>                 ret = data->chip->hwmon_init(data);
>                 if (ret < 0) {
> @@ -637,10 +735,17 @@ static int video_i2c_probe(struct i2c_client *client,
>
>         ret = video_register_device(&data->vdev, VFL_TYPE_GRABBER, -1);
>         if (ret < 0)
> -               goto error_unregister_device;
> +               goto error_pm_disable;
>
>         return 0;
>
> +error_pm_disable:
> +       pm_runtime_get_sync(&client->dev);
> +       pm_runtime_disable(&client->dev);
> +       pm_runtime_set_suspended(&client->dev);
> +       pm_runtime_put_noidle(&client->dev);
> +       data->chip->set_power(data, false);
> +
>  error_unregister_device:
>         v4l2_device_unregister(v4l2_dev);
>         mutex_destroy(&data->lock);
> @@ -654,6 +759,13 @@ static int video_i2c_remove(struct i2c_client *client)
>         struct video_i2c_data *data = i2c_get_clientdata(client);
>
>         video_unregister_device(&data->vdev);
> +
> +       pm_runtime_get_sync(&client->dev);
> +       pm_runtime_disable(&client->dev);
> +       pm_runtime_set_suspended(&client->dev);
> +       pm_runtime_put_noidle(&client->dev);
> +       data->chip->set_power(data, false);
> +
>         v4l2_device_unregister(&data->v4l2_dev);
>
>         mutex_destroy(&data->lock);
> @@ -662,6 +774,29 @@ static int video_i2c_remove(struct i2c_client *client)
>         return 0;
>  }
>
> +#ifdef CONFIG_PM
> +
> +static int video_i2c_pm_runtime_suspend(struct device *dev)
> +{
> +       struct video_i2c_data *data = i2c_get_clientdata(to_i2c_client(dev));
> +
> +       return data->chip->set_power(data, false);
> +}
> +
> +static int video_i2c_pm_runtime_resume(struct device *dev)
> +{
> +       struct video_i2c_data *data = i2c_get_clientdata(to_i2c_client(dev));
> +
> +       return data->chip->set_power(data, true);
> +}
> +
> +#endif
> +
> +static const struct dev_pm_ops video_i2c_pm_ops = {
> +       SET_RUNTIME_PM_OPS(video_i2c_pm_runtime_suspend,
> +                          video_i2c_pm_runtime_resume, NULL)
> +};
> +
>  static const struct i2c_device_id video_i2c_id_table[] = {
>         { "amg88xx", AMG88XX },
>         {}
> @@ -678,6 +813,7 @@ static struct i2c_driver video_i2c_driver = {
>         .driver = {
>                 .name   = VIDEO_I2C_DRIVER,
>                 .of_match_table = video_i2c_of_match,
> +               .pm     = &video_i2c_pm_ops,
>         },
>         .probe          = video_i2c_probe,
>         .remove         = video_i2c_remove,
> --
> 2.7.4
>
Akinobu Mita Sept. 18, 2018, 2:18 p.m. UTC | #2
2018年9月18日(火) 15:23 Matt Ranostay <matt.ranostay@konsulko.com>:
>
> On Mon, Sep 17, 2018 at 6:03 PM Akinobu Mita <akinobu.mita@gmail.com> wrote:
> >
> > AMG88xx has a register for setting operating mode.  This adds support
> > runtime PM by changing the operating mode.
> >
> > The instruction for changing sleep mode to normal mode is from the
> > reference specifications.
> >
> > https://docid81hrs3j1.cloudfront.net/medialibrary/2017/11/PANA-S-A0002141979-1.pdf
> >
> > Cc: Matt Ranostay <matt.ranostay@konsulko.com>
> > Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
> > Cc: Hans Verkuil <hansverk@cisco.com>
> > Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
> > Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
> > ---
> >  drivers/media/i2c/video-i2c.c | 140 +++++++++++++++++++++++++++++++++++++++++-
> >  1 file changed, 138 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/media/i2c/video-i2c.c b/drivers/media/i2c/video-i2c.c
> > index 916f36e..93822f4 100644
> > --- a/drivers/media/i2c/video-i2c.c
> > +++ b/drivers/media/i2c/video-i2c.c
> > @@ -17,6 +17,7 @@
> >  #include <linux/module.h>
> >  #include <linux/mutex.h>
> >  #include <linux/of_device.h>
> > +#include <linux/pm_runtime.h>
> >  #include <linux/regmap.h>
> >  #include <linux/sched.h>
> >  #include <linux/slab.h>
> > @@ -94,6 +95,9 @@ struct video_i2c_chip {
> >         /* xfer function */
> >         int (*xfer)(struct video_i2c_data *data, char *buf);
> >
> > +       /* power control function */
> > +       int (*set_power)(struct video_i2c_data *data, bool on);
> > +
> >         /* hwmon init function */
> >         int (*hwmon_init)(struct video_i2c_data *data);
> >  };
> > @@ -104,6 +108,14 @@ static int amg88xx_xfer(struct video_i2c_data *data, char *buf)
> >                                 data->chip->buffer_size);
> >  }
> >
> > +#define AMG88XX_REG_PCTL               0x00
> > +#define AMG88XX_PCTL_NORMAL            0x00
> > +#define AMG88XX_PCTL_SLEEP             0x10
> > +
> > +#define AMG88XX_REG_RST                        0x01
> > +#define AMG88XX_RST_FLAG               0x30
> > +#define AMG88XX_RST_INIT               0x3f
> > +
> >  #define AMG88XX_REG_FPSC               0x02
> >  #define AMG88XX_FPSC_1FPS              BIT(0)
> >
> > @@ -120,6 +132,59 @@ static int amg88xx_setup(struct video_i2c_data *data)
> >         return regmap_update_bits(data->regmap, AMG88XX_REG_FPSC, mask, val);
> >  }
> >
> > +static int amg88xx_set_power_on(struct video_i2c_data *data)
> > +{
> > +       int ret;
> > +
> > +       ret = regmap_write(data->regmap, AMG88XX_REG_PCTL, AMG88XX_PCTL_NORMAL);
> > +       if (ret)
> > +               return ret;
> > +
> > +       msleep(50);
> > +
> > +       ret = regmap_write(data->regmap, AMG88XX_REG_RST, AMG88XX_RST_INIT);
> > +       if (ret)
> > +               return ret;
> > +
> > +       msleep(2);
> > +
> > +       ret = regmap_write(data->regmap, AMG88XX_REG_RST, AMG88XX_RST_FLAG);
> > +       if (ret)
> > +               return ret;
> > +
> > +       /*
> > +        * Wait two frames before reading thermistor and temperature registers
> > +        */
> > +       msleep(200);
> > +
> > +       return 0;
> > +}
> > +
> > +static int amg88xx_set_power_off(struct video_i2c_data *data)
> > +{
> > +       int ret;
> > +
> > +       ret = regmap_write(data->regmap, AMG88XX_REG_PCTL, AMG88XX_PCTL_SLEEP);
> > +       if (ret)
> > +               return ret;
> > +       /*
> > +        * Wait for a while to avoid resuming normal mode immediately after
> > +        * entering sleep mode, otherwise the device occasionally goes wrong
> > +        * (thermistor and temperature registers are not updated at all)
> > +        */
> > +       msleep(100);
> > +
> > +       return 0;
> > +}
> > +
> > +static int amg88xx_set_power(struct video_i2c_data *data, bool on)
> > +{
> > +       if (on)
> > +               return amg88xx_set_power_on(data);
> > +
> > +       return amg88xx_set_power_off(data);
> > +}
> > +
> >  #if IS_ENABLED(CONFIG_HWMON)
> >
> >  static const u32 amg88xx_temp_config[] = {
> > @@ -151,7 +216,15 @@ static int amg88xx_read(struct device *dev, enum hwmon_sensor_types type,
> >         __le16 buf;
> >         int tmp;
> >
> > +       tmp = pm_runtime_get_sync(regmap_get_device(data->regmap));
> > +       if (tmp < 0) {
> > +               pm_runtime_put_noidle(regmap_get_device(data->regmap));
> > +               return tmp;
> > +       }
> > +
> >         tmp = regmap_bulk_read(data->regmap, 0x0e, &buf, 2);
> > +       pm_runtime_mark_last_busy(regmap_get_device(data->regmap));
> > +       pm_runtime_put_autosuspend(regmap_get_device(data->regmap));
> >         if (tmp)
> >                 return tmp;
> >
> > @@ -210,6 +283,7 @@ static const struct video_i2c_chip video_i2c_chip[] = {
> >                 .regmap_config  = &amg88xx_regmap_config,
> >                 .setup          = &amg88xx_setup,
> >                 .xfer           = &amg88xx_xfer,
> > +               .set_power      = amg88xx_set_power,
> >                 .hwmon_init     = amg88xx_hwmon_init,
> >         },
> >  };
> > @@ -336,14 +410,21 @@ static void video_i2c_del_list(struct vb2_queue *vq, enum vb2_buffer_state state
> >  static int start_streaming(struct vb2_queue *vq, unsigned int count)
> >  {
> >         struct video_i2c_data *data = vb2_get_drv_priv(vq);
> > +       struct device *dev = regmap_get_device(data->regmap);
> >         int ret;
> >
> >         if (data->kthread_vid_cap)
> >                 return 0;
> >
> > +       ret = pm_runtime_get_sync(dev);
> > +       if (ret < 0) {
> > +               pm_runtime_put_noidle(dev);
> > +               goto error_del_list;
> > +       }
> > +
> >         ret = data->chip->setup(data);
> >         if (ret)
> > -               goto error_del_list;
> > +               goto error_rpm_put;
> >
> >         data->sequence = 0;
> >         data->kthread_vid_cap = kthread_run(video_i2c_thread_vid_cap, data,
> > @@ -352,6 +433,9 @@ static int start_streaming(struct vb2_queue *vq, unsigned int count)
> >         if (!ret)
> >                 return 0;
> >
> > +error_rpm_put:
> > +       pm_runtime_mark_last_busy(dev);
> > +       pm_runtime_put_autosuspend(dev);
> >  error_del_list:
> >         video_i2c_del_list(vq, VB2_BUF_STATE_QUEUED);
> >
> > @@ -367,6 +451,8 @@ static void stop_streaming(struct vb2_queue *vq)
> >
> >         kthread_stop(data->kthread_vid_cap);
> >         data->kthread_vid_cap = NULL;
> > +       pm_runtime_mark_last_busy(regmap_get_device(data->regmap));
> > +       pm_runtime_put_autosuspend(regmap_get_device(data->regmap));
> >
> >         video_i2c_del_list(vq, VB2_BUF_STATE_ERROR);
> >  }
> > @@ -627,6 +713,18 @@ static int video_i2c_probe(struct i2c_client *client,
> >         video_set_drvdata(&data->vdev, data);
> >         i2c_set_clientdata(client, data);
> >
> > +       ret = data->chip->set_power(data, true);
> > +       if (ret)
> > +               goto error_unregister_device;
> > +
> > +       pm_runtime_get_noresume(&client->dev);
> > +       pm_runtime_set_active(&client->dev);
> > +       pm_runtime_enable(&client->dev);
> > +       pm_runtime_set_autosuspend_delay(&client->dev, 2000);
>
> 2 seconds arbitrary for runtime suspending? I could be blind (or that
> I can't read the part English + Japanese datasheet) but not sure how
> much power is saved in low-power mode.

According to 4-4) Detection characteristics,

Normal mode: Typ. 4.5 mA
Sleep mode: Typ. 0.2 mA

I arbitrarily selected 2 seconds for runtime suspending as it can be configured
to any value through sysfs interface.

> In any case looks fine to me.
>
> - Matt
>
> Reviewed-by: Matt Ranostay <matt.ranostay@konsulko.com>
>
> > +       pm_runtime_use_autosuspend(&client->dev);
> > +       pm_runtime_mark_last_busy(&client->dev);
> > +       pm_runtime_put_autosuspend(&client->dev);
> > +
> >         if (data->chip->hwmon_init) {
> >                 ret = data->chip->hwmon_init(data);
> >                 if (ret < 0) {
> > @@ -637,10 +735,17 @@ static int video_i2c_probe(struct i2c_client *client,
> >
> >         ret = video_register_device(&data->vdev, VFL_TYPE_GRABBER, -1);
> >         if (ret < 0)
> > -               goto error_unregister_device;
> > +               goto error_pm_disable;
> >
> >         return 0;
> >
> > +error_pm_disable:
> > +       pm_runtime_get_sync(&client->dev);
> > +       pm_runtime_disable(&client->dev);
> > +       pm_runtime_set_suspended(&client->dev);
> > +       pm_runtime_put_noidle(&client->dev);
> > +       data->chip->set_power(data, false);
> > +
> >  error_unregister_device:
> >         v4l2_device_unregister(v4l2_dev);
> >         mutex_destroy(&data->lock);
> > @@ -654,6 +759,13 @@ static int video_i2c_remove(struct i2c_client *client)
> >         struct video_i2c_data *data = i2c_get_clientdata(client);
> >
> >         video_unregister_device(&data->vdev);
> > +
> > +       pm_runtime_get_sync(&client->dev);
> > +       pm_runtime_disable(&client->dev);
> > +       pm_runtime_set_suspended(&client->dev);
> > +       pm_runtime_put_noidle(&client->dev);
> > +       data->chip->set_power(data, false);
> > +
> >         v4l2_device_unregister(&data->v4l2_dev);
> >
> >         mutex_destroy(&data->lock);
> > @@ -662,6 +774,29 @@ static int video_i2c_remove(struct i2c_client *client)
> >         return 0;
> >  }
> >
> > +#ifdef CONFIG_PM
> > +
> > +static int video_i2c_pm_runtime_suspend(struct device *dev)
> > +{
> > +       struct video_i2c_data *data = i2c_get_clientdata(to_i2c_client(dev));
> > +
> > +       return data->chip->set_power(data, false);
> > +}
> > +
> > +static int video_i2c_pm_runtime_resume(struct device *dev)
> > +{
> > +       struct video_i2c_data *data = i2c_get_clientdata(to_i2c_client(dev));
> > +
> > +       return data->chip->set_power(data, true);
> > +}
> > +
> > +#endif
> > +
> > +static const struct dev_pm_ops video_i2c_pm_ops = {
> > +       SET_RUNTIME_PM_OPS(video_i2c_pm_runtime_suspend,
> > +                          video_i2c_pm_runtime_resume, NULL)
> > +};
> > +
> >  static const struct i2c_device_id video_i2c_id_table[] = {
> >         { "amg88xx", AMG88XX },
> >         {}
> > @@ -678,6 +813,7 @@ static struct i2c_driver video_i2c_driver = {
> >         .driver = {
> >                 .name   = VIDEO_I2C_DRIVER,
> >                 .of_match_table = video_i2c_of_match,
> > +               .pm     = &video_i2c_pm_ops,
> >         },
> >         .probe          = video_i2c_probe,
> >         .remove         = video_i2c_remove,
> > --
> > 2.7.4
> >
diff mbox series

Patch

diff --git a/drivers/media/i2c/video-i2c.c b/drivers/media/i2c/video-i2c.c
index 916f36e..93822f4 100644
--- a/drivers/media/i2c/video-i2c.c
+++ b/drivers/media/i2c/video-i2c.c
@@ -17,6 +17,7 @@ 
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/of_device.h>
+#include <linux/pm_runtime.h>
 #include <linux/regmap.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
@@ -94,6 +95,9 @@  struct video_i2c_chip {
 	/* xfer function */
 	int (*xfer)(struct video_i2c_data *data, char *buf);
 
+	/* power control function */
+	int (*set_power)(struct video_i2c_data *data, bool on);
+
 	/* hwmon init function */
 	int (*hwmon_init)(struct video_i2c_data *data);
 };
@@ -104,6 +108,14 @@  static int amg88xx_xfer(struct video_i2c_data *data, char *buf)
 				data->chip->buffer_size);
 }
 
+#define AMG88XX_REG_PCTL		0x00
+#define AMG88XX_PCTL_NORMAL		0x00
+#define AMG88XX_PCTL_SLEEP		0x10
+
+#define AMG88XX_REG_RST			0x01
+#define AMG88XX_RST_FLAG		0x30
+#define AMG88XX_RST_INIT		0x3f
+
 #define AMG88XX_REG_FPSC		0x02
 #define AMG88XX_FPSC_1FPS		BIT(0)
 
@@ -120,6 +132,59 @@  static int amg88xx_setup(struct video_i2c_data *data)
 	return regmap_update_bits(data->regmap, AMG88XX_REG_FPSC, mask, val);
 }
 
+static int amg88xx_set_power_on(struct video_i2c_data *data)
+{
+	int ret;
+
+	ret = regmap_write(data->regmap, AMG88XX_REG_PCTL, AMG88XX_PCTL_NORMAL);
+	if (ret)
+		return ret;
+
+	msleep(50);
+
+	ret = regmap_write(data->regmap, AMG88XX_REG_RST, AMG88XX_RST_INIT);
+	if (ret)
+		return ret;
+
+	msleep(2);
+
+	ret = regmap_write(data->regmap, AMG88XX_REG_RST, AMG88XX_RST_FLAG);
+	if (ret)
+		return ret;
+
+	/*
+	 * Wait two frames before reading thermistor and temperature registers
+	 */
+	msleep(200);
+
+	return 0;
+}
+
+static int amg88xx_set_power_off(struct video_i2c_data *data)
+{
+	int ret;
+
+	ret = regmap_write(data->regmap, AMG88XX_REG_PCTL, AMG88XX_PCTL_SLEEP);
+	if (ret)
+		return ret;
+	/*
+	 * Wait for a while to avoid resuming normal mode immediately after
+	 * entering sleep mode, otherwise the device occasionally goes wrong
+	 * (thermistor and temperature registers are not updated at all)
+	 */
+	msleep(100);
+
+	return 0;
+}
+
+static int amg88xx_set_power(struct video_i2c_data *data, bool on)
+{
+	if (on)
+		return amg88xx_set_power_on(data);
+
+	return amg88xx_set_power_off(data);
+}
+
 #if IS_ENABLED(CONFIG_HWMON)
 
 static const u32 amg88xx_temp_config[] = {
@@ -151,7 +216,15 @@  static int amg88xx_read(struct device *dev, enum hwmon_sensor_types type,
 	__le16 buf;
 	int tmp;
 
+	tmp = pm_runtime_get_sync(regmap_get_device(data->regmap));
+	if (tmp < 0) {
+		pm_runtime_put_noidle(regmap_get_device(data->regmap));
+		return tmp;
+	}
+
 	tmp = regmap_bulk_read(data->regmap, 0x0e, &buf, 2);
+	pm_runtime_mark_last_busy(regmap_get_device(data->regmap));
+	pm_runtime_put_autosuspend(regmap_get_device(data->regmap));
 	if (tmp)
 		return tmp;
 
@@ -210,6 +283,7 @@  static const struct video_i2c_chip video_i2c_chip[] = {
 		.regmap_config	= &amg88xx_regmap_config,
 		.setup		= &amg88xx_setup,
 		.xfer		= &amg88xx_xfer,
+		.set_power	= amg88xx_set_power,
 		.hwmon_init	= amg88xx_hwmon_init,
 	},
 };
@@ -336,14 +410,21 @@  static void video_i2c_del_list(struct vb2_queue *vq, enum vb2_buffer_state state
 static int start_streaming(struct vb2_queue *vq, unsigned int count)
 {
 	struct video_i2c_data *data = vb2_get_drv_priv(vq);
+	struct device *dev = regmap_get_device(data->regmap);
 	int ret;
 
 	if (data->kthread_vid_cap)
 		return 0;
 
+	ret = pm_runtime_get_sync(dev);
+	if (ret < 0) {
+		pm_runtime_put_noidle(dev);
+		goto error_del_list;
+	}
+
 	ret = data->chip->setup(data);
 	if (ret)
-		goto error_del_list;
+		goto error_rpm_put;
 
 	data->sequence = 0;
 	data->kthread_vid_cap = kthread_run(video_i2c_thread_vid_cap, data,
@@ -352,6 +433,9 @@  static int start_streaming(struct vb2_queue *vq, unsigned int count)
 	if (!ret)
 		return 0;
 
+error_rpm_put:
+	pm_runtime_mark_last_busy(dev);
+	pm_runtime_put_autosuspend(dev);
 error_del_list:
 	video_i2c_del_list(vq, VB2_BUF_STATE_QUEUED);
 
@@ -367,6 +451,8 @@  static void stop_streaming(struct vb2_queue *vq)
 
 	kthread_stop(data->kthread_vid_cap);
 	data->kthread_vid_cap = NULL;
+	pm_runtime_mark_last_busy(regmap_get_device(data->regmap));
+	pm_runtime_put_autosuspend(regmap_get_device(data->regmap));
 
 	video_i2c_del_list(vq, VB2_BUF_STATE_ERROR);
 }
@@ -627,6 +713,18 @@  static int video_i2c_probe(struct i2c_client *client,
 	video_set_drvdata(&data->vdev, data);
 	i2c_set_clientdata(client, data);
 
+	ret = data->chip->set_power(data, true);
+	if (ret)
+		goto error_unregister_device;
+
+	pm_runtime_get_noresume(&client->dev);
+	pm_runtime_set_active(&client->dev);
+	pm_runtime_enable(&client->dev);
+	pm_runtime_set_autosuspend_delay(&client->dev, 2000);
+	pm_runtime_use_autosuspend(&client->dev);
+	pm_runtime_mark_last_busy(&client->dev);
+	pm_runtime_put_autosuspend(&client->dev);
+
 	if (data->chip->hwmon_init) {
 		ret = data->chip->hwmon_init(data);
 		if (ret < 0) {
@@ -637,10 +735,17 @@  static int video_i2c_probe(struct i2c_client *client,
 
 	ret = video_register_device(&data->vdev, VFL_TYPE_GRABBER, -1);
 	if (ret < 0)
-		goto error_unregister_device;
+		goto error_pm_disable;
 
 	return 0;
 
+error_pm_disable:
+	pm_runtime_get_sync(&client->dev);
+	pm_runtime_disable(&client->dev);
+	pm_runtime_set_suspended(&client->dev);
+	pm_runtime_put_noidle(&client->dev);
+	data->chip->set_power(data, false);
+
 error_unregister_device:
 	v4l2_device_unregister(v4l2_dev);
 	mutex_destroy(&data->lock);
@@ -654,6 +759,13 @@  static int video_i2c_remove(struct i2c_client *client)
 	struct video_i2c_data *data = i2c_get_clientdata(client);
 
 	video_unregister_device(&data->vdev);
+
+	pm_runtime_get_sync(&client->dev);
+	pm_runtime_disable(&client->dev);
+	pm_runtime_set_suspended(&client->dev);
+	pm_runtime_put_noidle(&client->dev);
+	data->chip->set_power(data, false);
+
 	v4l2_device_unregister(&data->v4l2_dev);
 
 	mutex_destroy(&data->lock);
@@ -662,6 +774,29 @@  static int video_i2c_remove(struct i2c_client *client)
 	return 0;
 }
 
+#ifdef CONFIG_PM
+
+static int video_i2c_pm_runtime_suspend(struct device *dev)
+{
+	struct video_i2c_data *data = i2c_get_clientdata(to_i2c_client(dev));
+
+	return data->chip->set_power(data, false);
+}
+
+static int video_i2c_pm_runtime_resume(struct device *dev)
+{
+	struct video_i2c_data *data = i2c_get_clientdata(to_i2c_client(dev));
+
+	return data->chip->set_power(data, true);
+}
+
+#endif
+
+static const struct dev_pm_ops video_i2c_pm_ops = {
+	SET_RUNTIME_PM_OPS(video_i2c_pm_runtime_suspend,
+			   video_i2c_pm_runtime_resume, NULL)
+};
+
 static const struct i2c_device_id video_i2c_id_table[] = {
 	{ "amg88xx", AMG88XX },
 	{}
@@ -678,6 +813,7 @@  static struct i2c_driver video_i2c_driver = {
 	.driver = {
 		.name	= VIDEO_I2C_DRIVER,
 		.of_match_table = video_i2c_of_match,
+		.pm	= &video_i2c_pm_ops,
 	},
 	.probe		= video_i2c_probe,
 	.remove		= video_i2c_remove,