On 10/20/2018 04:26 PM, Akinobu Mita 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.ranos...@konsulko.com>
> Cc: Sakari Ailus <sakari.ai...@linux.intel.com>
> Cc: Hans Verkuil <hansv...@cisco.com>
> Cc: Mauro Carvalho Chehab <mche...@kernel.org>
> Reviewed-by: Matt Ranostay <matt.ranos...@konsulko.com>
> Acked-by: Sakari Ailus <sakari.ai...@linux.intel.com>
> Signed-off-by: Akinobu Mita <akinobu.m...@gmail.com>
> ---
> * v4
> - Move set_power() call into release() callback
> 
>  drivers/media/i2c/video-i2c.c | 141 
> +++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 139 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/media/i2c/video-i2c.c b/drivers/media/i2c/video-i2c.c
> index 3334fc2..384a046 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>
> @@ -94,10 +95,23 @@ 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);
>  };
>  
> +/* Power control register */
> +#define AMG88XX_REG_PCTL     0x00
> +#define AMG88XX_PCTL_NORMAL          0x00
> +#define AMG88XX_PCTL_SLEEP           0x10
> +
> +/* Reset register */
> +#define AMG88XX_REG_RST              0x01
> +#define AMG88XX_RST_FLAG             0x30
> +#define AMG88XX_RST_INIT             0x3f
> +
>  /* Frame rate register */
>  #define AMG88XX_REG_FPSC     0x02
>  #define AMG88XX_FPSC_1FPS            BIT(0)
> @@ -127,6 +141,59 @@ 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);

WARNING: msleep < 20ms can sleep for up to 20ms; see 
Documentation/timers/timers-howto.txt
#55: FILE: drivers/media/i2c/video-i2c.c:158:
+       msleep(2);

Use usleep_range instead.

Regards,

        Hans

> +
> +     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[] = {
> @@ -158,7 +225,15 @@ 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, AMG88XX_REG_TTHL, &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;
>  
> @@ -217,6 +292,7 @@ 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,
>       },
>  };
> @@ -343,14 +419,21 @@ 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,
> @@ -359,6 +442,9 @@ 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);
>  
> @@ -374,6 +460,8 @@ 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);
>  }
> @@ -648,6 +736,16 @@ 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);
> +
>       if (data->chip->hwmon_init) {
>               ret = data->chip->hwmon_init(data);
>               if (ret < 0) {
> @@ -658,10 +756,19 @@ 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;
> +
> +     pm_runtime_mark_last_busy(&client->dev);
> +     pm_runtime_put_autosuspend(&client->dev);
>  
>       return 0;
>  
> +error_pm_disable:
> +     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);
> @@ -680,11 +787,40 @@ static int video_i2c_remove(struct i2c_client *client)
>  {
>       struct video_i2c_data *data = i2c_get_clientdata(client);
>  
> +     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);
> +
>       video_unregister_device(&data->vdev);
>  
>       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 },
>       {}
> @@ -701,6 +837,7 @@ 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,
> 

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