Re: [PATCH] iio: tsl2583: add runtime power management support

[Jonathan Cameron]

On 25/04/17 09:06, Brian Masney wrote:
> This patch adds runtime power management support to the tsl2583 driver.
> The device is powered off after two seconds of inactivity. Verified that
> the driver still functions correctly using a TSL2581 hooked up to a
> Raspberry Pi 2.
> 
> Signed-off-by: Brian Masney <masneyb@xxxxxxxxxxxxx>
Looks fine to me. Not being a particular expert in the runtime pm code
I'd like to let it sit on the list for a little while in the hope of
a bit of confirmation from those more knowledgeable about this than me.

Give me a poke if I haven't picked it up in the next week or two.

Thanks,

Jonathan
> ---
>  drivers/iio/light/tsl2583.c | 106 +++++++++++++++++++++++++++++++-------------
>  1 file changed, 76 insertions(+), 30 deletions(-)
> 
> diff --git a/drivers/iio/light/tsl2583.c b/drivers/iio/light/tsl2583.c
> index a78b602..1679181 100644
> --- a/drivers/iio/light/tsl2583.c
> +++ b/drivers/iio/light/tsl2583.c
> @@ -3,7 +3,7 @@
>   * within the TAOS tsl258x family of devices (tsl2580, tsl2581, tsl2583).
>   *
>   * Copyright (c) 2011, TAOS Corporation.
> - * Copyright (c) 2016 Brian Masney <masneyb@xxxxxxxxxxxxx>
> + * Copyright (c) 2016-2017 Brian Masney <masneyb@xxxxxxxxxxxxx>
>   *
>   * This program is free software; you can redistribute it and/or modify
>   * it under the terms of the GNU General Public License as published by
> @@ -27,6 +27,7 @@
>  #include <linux/module.h>
>  #include <linux/iio/iio.h>
>  #include <linux/iio/sysfs.h>
> +#include <linux/pm_runtime.h>
>  
>  /* Device Registers and Masks */
>  #define TSL2583_CNTRL			0x00
> @@ -64,6 +65,8 @@
>  #define TSL2583_CHIP_ID			0x90
>  #define TSL2583_CHIP_ID_MASK		0xf0
>  
> +#define TSL2583_POWER_OFF_DELAY_MS	2000
> +
>  /* Per-device data */
>  struct tsl2583_als_info {
>  	u16 als_ch0;
> @@ -108,7 +111,6 @@ struct tsl2583_chip {
>  	struct tsl2583_settings als_settings;
>  	int als_time_scale;
>  	int als_saturation;
> -	bool suspended;
>  };
>  
>  struct gainadj {
> @@ -460,8 +462,6 @@ static int tsl2583_chip_init_and_power_on(struct iio_dev *indio_dev)
>  	if (ret < 0)
>  		return ret;
>  
> -	chip->suspended = false;
> -
>  	return ret;
>  }
>  
> @@ -513,11 +513,6 @@ static ssize_t in_illuminance_calibrate_store(struct device *dev,
>  
>  	mutex_lock(&chip->als_mutex);
>  
> -	if (chip->suspended) {
> -		ret = -EBUSY;
> -		goto done;
> -	}
> -
>  	ret = tsl2583_als_calibrate(indio_dev);
>  	if (ret < 0)
>  		goto done;
> @@ -645,20 +640,36 @@ static const struct iio_chan_spec tsl2583_channels[] = {
>  	},
>  };
>  
> +static int tsl2583_set_pm_runtime_busy(struct tsl2583_chip *chip, bool on)
> +{
> +	int ret;
> +
> +	if (on) {
> +		ret = pm_runtime_get_sync(&chip->client->dev);
> +		if (ret < 0)
> +			pm_runtime_put_noidle(&chip->client->dev);
> +	} else {
> +		pm_runtime_mark_last_busy(&chip->client->dev);
> +		ret = pm_runtime_put_autosuspend(&chip->client->dev);
> +	}
> +
> +	return ret;
> +}
> +
>  static int tsl2583_read_raw(struct iio_dev *indio_dev,
>  			    struct iio_chan_spec const *chan,
>  			    int *val, int *val2, long mask)
>  {
>  	struct tsl2583_chip *chip = iio_priv(indio_dev);
> -	int ret = -EINVAL;
> +	int ret, pm_ret;
>  
> -	mutex_lock(&chip->als_mutex);
> +	ret = tsl2583_set_pm_runtime_busy(chip, true);
> +	if (ret < 0)
> +		return ret;
>  
> -	if (chip->suspended) {
> -		ret = -EBUSY;
> -		goto read_done;
> -	}
> +	mutex_lock(&chip->als_mutex);
>  
> +	ret = -EINVAL;
>  	switch (mask) {
>  	case IIO_CHAN_INFO_RAW:
>  		if (chan->type == IIO_LIGHT) {
> @@ -719,6 +730,18 @@ static int tsl2583_read_raw(struct iio_dev *indio_dev,
>  read_done:
>  	mutex_unlock(&chip->als_mutex);
>  
> +	if (ret < 0)
> +		return ret;
> +
> +	/*
> +	 * Preserve the ret variable if the call to
> +	 * tsl2583_set_pm_runtime_busy() is successful so the reading
> +	 * (if applicable) is returned to user space.
> +	 */
> +	pm_ret = tsl2583_set_pm_runtime_busy(chip, false);
> +	if (pm_ret < 0)
> +		return pm_ret;
> +
>  	return ret;
>  }
>  
> @@ -727,15 +750,15 @@ static int tsl2583_write_raw(struct iio_dev *indio_dev,
>  			     int val, int val2, long mask)
>  {
>  	struct tsl2583_chip *chip = iio_priv(indio_dev);
> -	int ret = -EINVAL;
> +	int ret;
>  
> -	mutex_lock(&chip->als_mutex);
> +	ret = tsl2583_set_pm_runtime_busy(chip, true);
> +	if (ret < 0)
> +		return ret;
>  
> -	if (chip->suspended) {
> -		ret = -EBUSY;
> -		goto write_done;
> -	}
> +	mutex_lock(&chip->als_mutex);
>  
> +	ret = -EINVAL;
>  	switch (mask) {
>  	case IIO_CHAN_INFO_CALIBBIAS:
>  		if (chan->type == IIO_LIGHT) {
> @@ -767,9 +790,15 @@ static int tsl2583_write_raw(struct iio_dev *indio_dev,
>  		break;
>  	}
>  
> -write_done:
>  	mutex_unlock(&chip->als_mutex);
>  
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = tsl2583_set_pm_runtime_busy(chip, false);
> +	if (ret < 0)
> +		return ret;
> +
>  	return ret;
>  }
>  
> @@ -803,7 +832,6 @@ static int tsl2583_probe(struct i2c_client *clientp,
>  	i2c_set_clientdata(clientp, indio_dev);
>  
>  	mutex_init(&chip->als_mutex);
> -	chip->suspended = true;
>  
>  	ret = i2c_smbus_read_byte_data(clientp,
>  				       TSL2583_CMD_REG | TSL2583_CHIPID);
> @@ -826,6 +854,11 @@ static int tsl2583_probe(struct i2c_client *clientp,
>  	indio_dev->modes = INDIO_DIRECT_MODE;
>  	indio_dev->name = chip->client->name;
>  
> +	pm_runtime_enable(&clientp->dev);
> +	pm_runtime_set_autosuspend_delay(&clientp->dev,
> +					 TSL2583_POWER_OFF_DELAY_MS);
> +	pm_runtime_use_autosuspend(&clientp->dev);
> +
>  	ret = devm_iio_device_register(indio_dev->dev.parent, indio_dev);
>  	if (ret) {
>  		dev_err(&clientp->dev, "%s: iio registration failed\n",
> @@ -836,16 +869,25 @@ static int tsl2583_probe(struct i2c_client *clientp,
>  	/* Load up the V2 defaults (these are hard coded defaults for now) */
>  	tsl2583_defaults(chip);
>  
> -	/* Make sure the chip is on */
> -	ret = tsl2583_chip_init_and_power_on(indio_dev);
> -	if (ret < 0)
> -		return ret;
> -
>  	dev_info(&clientp->dev, "Light sensor found.\n");
>  
>  	return 0;
>  }
>  
> +static int tsl2583_remove(struct i2c_client *client)
> +{
> +	struct iio_dev *indio_dev = i2c_get_clientdata(client);
> +	struct tsl2583_chip *chip = iio_priv(indio_dev);
> +
> +	iio_device_unregister(indio_dev);
> +
> +	pm_runtime_disable(&client->dev);
> +	pm_runtime_set_suspended(&client->dev);
> +	pm_runtime_put_noidle(&client->dev);
> +
> +	return tsl2583_set_power_state(chip, TSL2583_CNTL_PWR_OFF);
> +}
> +
>  static int __maybe_unused tsl2583_suspend(struct device *dev)
>  {
>  	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
> @@ -855,7 +897,6 @@ static int __maybe_unused tsl2583_suspend(struct device *dev)
>  	mutex_lock(&chip->als_mutex);
>  
>  	ret = tsl2583_set_power_state(chip, TSL2583_CNTL_PWR_OFF);
> -	chip->suspended = true;
>  
>  	mutex_unlock(&chip->als_mutex);
>  
> @@ -877,7 +918,11 @@ static int __maybe_unused tsl2583_resume(struct device *dev)
>  	return ret;
>  }
>  
> -static SIMPLE_DEV_PM_OPS(tsl2583_pm_ops, tsl2583_suspend, tsl2583_resume);
> +static const struct dev_pm_ops tsl2583_pm_ops = {
> +	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
> +				pm_runtime_force_resume)
> +	SET_RUNTIME_PM_OPS(tsl2583_suspend, tsl2583_resume, NULL)
> +};
>  
>  static struct i2c_device_id tsl2583_idtable[] = {
>  	{ "tsl2580", 0 },
> @@ -904,6 +949,7 @@ static struct i2c_driver tsl2583_driver = {
>  	},
>  	.id_table = tsl2583_idtable,
>  	.probe = tsl2583_probe,
> +	.remove = tsl2583_remove,
>  };
>  module_i2c_driver(tsl2583_driver);
>  
>