Re: [PATCH 4/5] iio: light: us8152d: Add power management support

[Jonathan Cameron <jic23@kernel.org>]

On 24/11/15 10:59, Adriana Reus wrote:
> Add power management for sleep as well as runtime pm.
> 
> Signed-off-by: Adriana Reus <adriana.reus@intel.com>
Mostly fine, but a comment on a possible future tidy up inline.

Applied to the togreg branch of iio.git - initially pushed out as
testing for the autobuilders to play with it.

> ---
>  drivers/iio/light/us5182d.c | 95 +++++++++++++++++++++++++++++++++++++++++----
>  1 file changed, 88 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/iio/light/us5182d.c b/drivers/iio/light/us5182d.c
> index 3d959f3..60cab4a 100644
> --- a/drivers/iio/light/us5182d.c
> +++ b/drivers/iio/light/us5182d.c
> @@ -23,6 +23,8 @@
>  #include <linux/iio/iio.h>
>  #include <linux/iio/sysfs.h>
>  #include <linux/mutex.h>
> +#include <linux/pm.h>
> +#include <linux/pm_runtime.h>
>  
>  #define US5182D_REG_CFG0				0x00
>  #define US5182D_CFG0_ONESHOT_EN				BIT(6)
> @@ -81,6 +83,7 @@
>  #define US5182D_READ_BYTE			1
>  #define US5182D_READ_WORD			2
>  #define US5182D_OPSTORE_SLEEP_TIME		20 /* ms */
> +#define US5182D_SLEEP_MS			3000 /* ms */
>  
>  /* Available ranges: [12354, 7065, 3998, 2202, 1285, 498, 256, 138] lux */
>  static const int us5182d_scales[] = {188500, 107800, 61000, 33600, 19600, 7600,
> @@ -298,6 +301,26 @@ static int us5182d_shutdown_en (struct us5182d_data *data, u8 state)
>  	return ret;
>  }
>  
> +
> +static int us5182d_set_power_state(struct us5182d_data *data, bool on)
> +{
> +	int ret;
> +
> +	if (data->power_mode == US5182D_ONESHOT)
> +		return 0;
> +
> +	if (on) {
> +		ret = pm_runtime_get_sync(&data->client->dev);
> +		if (ret < 0)
> +			pm_runtime_put_noidle(&data->client->dev);
> +	} else {
> +		pm_runtime_mark_last_busy(&data->client->dev);
> +		ret = pm_runtime_put_autosuspend(&data->client->dev);
> +	}
> +
> +	return ret;
> +}
> +
>  static int us5182d_read_raw(struct iio_dev *indio_dev,
>  			    struct iio_chan_spec const *chan, int *val,
>  			    int *val2, long mask)
> @@ -315,15 +338,20 @@ static int us5182d_read_raw(struct iio_dev *indio_dev,
>  				if (ret < 0)
>  					goto out_err;
>  			}
> -			ret = us5182d_als_enable(data);
> +			ret = us5182d_set_power_state(data, true);
>  			if (ret < 0)
>  				goto out_err;
> -
> +			ret = us5182d_als_enable(data);
> +			if (ret < 0)
> +				goto out_poweroff;
>  			ret = us5182d_get_als(data);
>  			if (ret < 0)
> +				goto out_poweroff;
> +			*val = ret;
> +			ret = us5182d_set_power_state(data, false);
> +			if (ret < 0)
>  				goto out_err;
>  			mutex_unlock(&data->lock);
> -			*val = ret;
>  			return IIO_VAL_INT;
>  		case IIO_PROXIMITY:
I'd argue the complexity of this has reached the point where ideally you'd
break it out to a function.  The jumps out of the switch statement are 
particularly nasty from a readability point of view.

Perhaps a job for a followup patch?
>  			mutex_lock(&data->lock);
> @@ -332,17 +360,22 @@ static int us5182d_read_raw(struct iio_dev *indio_dev,
>  				if (ret < 0)
>  					goto out_err;
>  			}
> -			ret = us5182d_px_enable(data);
> +			ret = us5182d_set_power_state(data, true);
>  			if (ret < 0)
>  				goto out_err;
> -
> +			ret = us5182d_px_enable(data);
> +			if (ret < 0)
> +				goto out_poweroff;
>  			ret = i2c_smbus_read_word_data(data->client,
>  						       US5182D_REG_PDL);
>  			if (ret < 0)
> +				goto out_poweroff;
> +			*val = ret;
> +			ret = us5182d_set_power_state(data, false);
> +			if (ret < 0)
>  				goto out_err;
>  			mutex_unlock(&data->lock);
> -			*val = ret;
> -			return  IIO_VAL_INT;
> +			return IIO_VAL_INT;
This is a little bit of noise that should have been dealt with separately...

>  		default:
>  			return -EINVAL;
>  		}
> @@ -361,6 +394,9 @@ static int us5182d_read_raw(struct iio_dev *indio_dev,
>  	}
>  
>  	return -EINVAL;
> +
> +out_poweroff:
> +	us5182d_set_power_state(data, false);
>  out_err:
>  	mutex_unlock(&data->lock);
>  	return ret;
> @@ -577,6 +613,17 @@ static int us5182d_probe(struct i2c_client *client,
>  	if (ret < 0)
>  		goto out_err;
>  
> +	if (data->default_continuous) {
> +		pm_runtime_set_active(&client->dev);
> +		if (ret < 0)
> +			goto out_err;
> +	}
> +
> +	pm_runtime_enable(&client->dev);
> +	pm_runtime_set_autosuspend_delay(&client->dev,
> +					 US5182D_SLEEP_MS);
> +	pm_runtime_use_autosuspend(&client->dev);
> +
>  	ret = iio_device_register(indio_dev);
>  	if (ret < 0)
>  		goto out_err;
> @@ -595,9 +642,42 @@ static int us5182d_remove(struct i2c_client *client)
>  
>  	iio_device_unregister(i2c_get_clientdata(client));
>  
> +	pm_runtime_disable(&client->dev);
> +	pm_runtime_set_suspended(&client->dev);
> +
>  	return us5182d_shutdown_en(data, US5182D_CFG0_SHUTDOWN_EN);
>  }
>  
> +#if defined(CONFIG_PM_SLEEP) || defined(CONFIG_PM)
> +static int us5182d_suspend(struct device *dev)
> +{
> +	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
> +	struct us5182d_data *data = iio_priv(indio_dev);
> +
> +	if (data->power_mode == US5182D_CONTINUOUS)
> +		return us5182d_shutdown_en(data, US5182D_CFG0_SHUTDOWN_EN);
> +
> +	return 0;
> +}
> +
> +static int us5182d_resume(struct device *dev)
> +{
> +	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
> +	struct us5182d_data *data = iio_priv(indio_dev);
> +
> +	if (data->power_mode == US5182D_CONTINUOUS)
> +		return us5182d_shutdown_en(data,
> +					   ~US5182D_CFG0_SHUTDOWN_EN & 0xff);
> +
> +	return 0;
> +}
> +#endif
> +
> +static const struct dev_pm_ops us5182d_pm_ops = {
> +	SET_SYSTEM_SLEEP_PM_OPS(us5182d_suspend, us5182d_resume)
> +	SET_RUNTIME_PM_OPS(us5182d_suspend, us5182d_resume, NULL)
> +};
> +
>  static const struct acpi_device_id us5182d_acpi_match[] = {
>  	{ "USD5182", 0},
>  	{}
> @@ -615,6 +695,7 @@ MODULE_DEVICE_TABLE(i2c, us5182d_id);
>  static struct i2c_driver us5182d_driver = {
>  	.driver = {
>  		.name = US5182D_DRV_NAME,
> +		.pm = &us5182d_pm_ops,
>  		.acpi_match_table = ACPI_PTR(us5182d_acpi_match),
>  	},
>  	.probe = us5182d_probe,
>