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Date: Wed, 26 Apr 2017 06:16:34 +0100
From: Jonathan Cameron <jic23@...nel.org>
To: Brian Masney <masneyb@...tation.org>, linux-iio@...r.kernel.org
Cc: knaack.h@....de, lars@...afoo.de, pmeerw@...erw.net,
linux-kernel@...r.kernel.org, jbrenner@...sinc.com
Subject: Re: [PATCH] iio: tsl2583: add runtime power management support
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@...tation.org>
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@...tation.org>
> + * Copyright (c) 2016-2017 Brian Masney <masneyb@...tation.org>
> *
> * 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);
>
>
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