Re: [PATCH v4 3/6] iio: imu: kmx61: Add PM runtime support

[Hartmut Knaack <knaack.h@gmx.de>]

Daniel Baluta schrieb am 03.12.2014 um 14:31:
> By default both sensors are ACTIVE, in this way the driver
> will work even if CONFIG_PM_RUNTIME is not selected.
> 
Since kmx61_set_power_state() can return error codes, wouldn't it be better to
handle them (as long as you are not using it in an error handler)?
Thanks,

Hartmut
> Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
> ---
>  drivers/iio/imu/kmx61.c | 114 +++++++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 112 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iio/imu/kmx61.c b/drivers/iio/imu/kmx61.c
> index 893f7c8..7536043 100644
> --- a/drivers/iio/imu/kmx61.c
> +++ b/drivers/iio/imu/kmx61.c
> @@ -15,6 +15,8 @@
>  #include <linux/i2c.h>
>  #include <linux/acpi.h>
>  #include <linux/gpio/consumer.h>
> +#include <linux/interrupt.h>
> +#include <linux/pm_runtime.h>
>  #include <linux/iio/iio.h>
>  #include <linux/iio/sysfs.h>
>  
> @@ -69,6 +71,8 @@
>  #define KMX61_ACC_ODR_MASK	0x0F
>  #define KMX61_MAG_ODR_MASK	0xF0
>  
> +#define KMX61_SLEEP_DELAY_MS	2000
> +
>  #define KMX61_CHIP_ID		0x12
>  
>  /* KMX61 devices */
> @@ -85,6 +89,10 @@ struct kmx61_data {
>  	bool acc_stby;
>  	bool mag_stby;
>  
> +	/* power state */
> +	bool acc_ps;
> +	bool mag_ps;
> +
>  	/* config bits */
>  	u8 range;
>  	u8 odr_bits;
> @@ -457,6 +465,58 @@ static int kmx61_chip_init(struct kmx61_data *data)
>  	return 0;
>  }
>  
> +/**
> + * kmx61_set_power_state() - set power state for kmx61 @device
> + * @data - kmx61 device private pointer
> + * @on - power state to be set for @device
> + * @device - bitmask indicating device for which @on state needs to be set
> + *
> + * Notice that when ACC power state needs to be set to ON and MAG is in
> + * OPERATION then we know that kmx61_runtime_resume was already called
> + * so we must set ACC OPERATION mode here. The same happens when MAG power
> + * state needs to be set to ON and ACC is in OPERATION.
> + */
> +static int kmx61_set_power_state(struct kmx61_data *data, bool on, u8 device)
> +{
> +#ifdef CONFIG_PM_RUNTIME
> +	int ret;
> +
> +	if (device & KMX61_ACC) {
> +		if (on && !data->acc_ps && !data->mag_stby) {
> +			ret = kmx61_set_mode(data, 0, KMX61_ACC, true);
> +			if (ret < 0)
> +				return ret;
> +		}
> +		data->acc_ps = on;
> +	}
> +	if (device & KMX61_MAG) {
> +		if (on && !data->mag_ps && !data->acc_stby) {
> +			ret = kmx61_set_mode(data, 0, KMX61_MAG, true);
> +			if (ret < 0)
> +				return ret;
> +		}
> +		data->mag_ps = on;
> +	}
> +
> +	if (on) {
> +		ret = pm_runtime_get_sync(&data->client->dev);
> +	} else {
> +		pm_runtime_mark_last_busy(&data->client->dev);
> +		ret = pm_runtime_put_autosuspend(&data->client->dev);
> +	}
> +	if (ret < 0) {
> +		dev_err(&data->client->dev,
> +			"Failed: kmx61_set_power_state for %d, ret %d\n",
> +			on, ret);
> +		if (on)
> +			pm_runtime_put_noidle(&data->client->dev);
> +
> +		return ret;
> +	}
> +#endif
> +	return 0;
> +}
> +
>  static int kmx61_read_measurement(struct kmx61_data *data, u8 base, u8 offset)
>  {
>  	int ret;
> @@ -491,13 +551,16 @@ static int kmx61_read_raw(struct iio_dev *indio_dev,
>  		}
>  		mutex_lock(&data->lock);
>  
> +		kmx61_set_power_state(data, true, chan->address);
>  		ret = kmx61_read_measurement(data, base_reg, chan->scan_index);
>  		if (ret < 0) {
> +			kmx61_set_power_state(data, false, chan->address);
>  			mutex_unlock(&data->lock);
>  			return ret;
>  		}
>  		*val = sign_extend32(ret >> chan->scan_type.shift,
>  				     chan->scan_type.realbits - 1);
> +		kmx61_set_power_state(data, false, chan->address);
>  
>  		mutex_unlock(&data->lock);
>  		return IIO_VAL_INT;
> @@ -693,12 +756,22 @@ static int kmx61_probe(struct i2c_client *client,
>  	ret = iio_device_register(data->mag_indio_dev);
>  	if (ret < 0) {
>  		dev_err(&client->dev, "Failed to register mag iio device\n");
> -		goto err_iio_unregister;
> +		goto err_iio_unregister_acc;
>  	}
>  
> +	ret = pm_runtime_set_active(&client->dev);
> +	if (ret < 0)
> +		goto err_iio_unregister_mag;
> +
> +	pm_runtime_enable(&client->dev);
> +	pm_runtime_set_autosuspend_delay(&client->dev, KMX61_SLEEP_DELAY_MS);
> +	pm_runtime_use_autosuspend(&client->dev);
> +
>  	return 0;
>  
> -err_iio_unregister:
> +err_iio_unregister_mag:
> +	iio_device_unregister(data->mag_indio_dev);
> +err_iio_unregister_acc:
>  	iio_device_unregister(data->acc_indio_dev);
>  err_chip_uninit:
>  	kmx61_set_mode(data, KMX61_ALL_STBY, KMX61_ACC | KMX61_MAG, true);
> @@ -709,6 +782,10 @@ static int kmx61_remove(struct i2c_client *client)
>  {
>  	struct kmx61_data *data = i2c_get_clientdata(client);
>  
> +	pm_runtime_disable(&client->dev);
> +	pm_runtime_set_suspended(&client->dev);
> +	pm_runtime_put_noidle(&client->dev);
> +
>  	iio_device_unregister(data->acc_indio_dev);
>  	iio_device_unregister(data->mag_indio_dev);
>  
> @@ -719,6 +796,38 @@ static int kmx61_remove(struct i2c_client *client)
>  	return 0;
>  }
>  
> +
> +#ifdef CONFIG_PM_RUNTIME
> +static int kmx61_runtime_suspend(struct device *dev)
> +{
> +	struct kmx61_data *data = i2c_get_clientdata(to_i2c_client(dev));
> +	int ret;
> +
> +	mutex_lock(&data->lock);
> +	ret = kmx61_set_mode(data, KMX61_ALL_STBY, KMX61_ACC | KMX61_MAG, true);
> +	mutex_unlock(&data->lock);
> +
> +	return ret;
> +}
> +
> +static int kmx61_runtime_resume(struct device *dev)
> +{
> +	struct kmx61_data *data = i2c_get_clientdata(to_i2c_client(dev));
> +	u8 stby = 0;
> +
> +	if (!data->acc_ps)
> +		stby |= KMX61_ACC_STBY_BIT;
> +	if (!data->mag_ps)
> +		stby |= KMX61_MAG_STBY_BIT;
> +
> +	return kmx61_set_mode(data, stby, KMX61_ACC | KMX61_MAG, true);
> +}
> +#endif
> +
> +static const struct dev_pm_ops kmx61_pm_ops = {
> +	SET_RUNTIME_PM_OPS(kmx61_runtime_suspend, kmx61_runtime_resume, NULL)
> +};
> +
>  static const struct acpi_device_id kmx61_acpi_match[] = {
>  	{"KMX61021", 0},
>  	{}
> @@ -737,6 +846,7 @@ static struct i2c_driver kmx61_driver = {
>  	.driver = {
>  		.name = KMX61_DRV_NAME,
>  		.acpi_match_table = ACPI_PTR(kmx61_acpi_match),
> +		.pm = &kmx61_pm_ops,
>  	},
>  	.probe		= kmx61_probe,
>  	.remove		= kmx61_remove,
>