Re: [PATCH] iio: isl29018: Support suspend and resume.

Jonathan Cameron
2012-11-02T09:53:05Z

On 10/25/2012 12:39 AM, Bryan Freed wrote:
> The driver leaves the device in power-down state anyway,
> so there is nothing to do on suspend.
> On resume, we just have to make sure the range and ADC
> values are updated in the device since it may have been
> powered down in suspend.
>
> Signed-off-by: Bryan Freed <bfreed@chromium.org>
Added to togreg branch of iio.git
though the various uses of power down in the description had
me scratching my head for a second.

I'm guessing auto power-down means the chip is locally disabled
but in suspend it's possible the power supply will be cut
to the chip rather than it simply powering down internally...
> ---
> drivers/staging/iio/light/isl29018.c | 45 ++++++++++++++++++++++++++++++++++
> 1 files changed, 45 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/staging/iio/light/isl29018.c b/drivers/staging/iio/light/isl29018.c
> index 6ee5567..3b03f6f 100644
> --- a/drivers/staging/iio/light/isl29018.c
> +++ b/drivers/staging/iio/light/isl29018.c
> @@ -67,6 +67,7 @@ struct isl29018_chip {
> unsigned int range;
> unsigned int adc_bit;
> int prox_scheme;
> + bool suspended;
> };
>
> static int isl29018_set_range(struct isl29018_chip *chip, unsigned long range,
> @@ -368,6 +369,10 @@ static int isl29018_read_raw(struct iio_dev *indio_dev,
> struct isl29018_chip *chip = iio_priv(indio_dev);
>
> mutex_lock(&chip->lock);
> + if (chip->suspended) {
> + mutex_unlock(&chip->lock);
> + return -EBUSY;
> + }
> switch (mask) {
> case IIO_CHAN_INFO_RAW:
> case IIO_CHAN_INFO_PROCESSED:
> @@ -561,6 +566,7 @@ static int __devinit isl29018_probe(struct i2c_client *client,
> chip->lux_scale = 1;
> chip->range = 1000;
> chip->adc_bit = 16;
> + chip->suspended = false;
>
> chip->regmap = devm_regmap_init_i2c(client, &isl29018_regmap_config);
> if (IS_ERR(chip->regmap)) {
> @@ -603,6 +609,44 @@ static int __devexit isl29018_remove(struct i2c_client *client)
> return 0;
> }
>
> +#ifdef CONFIG_PM_SLEEP
> +static int isl29018_suspend(struct device *dev)
> +{
> + struct isl29018_chip *chip = iio_priv(dev_get_drvdata(dev));
> +
> + mutex_lock(&chip->lock);
> +
> + /* Since this driver uses only polling commands, we are by default in
> + * auto shutdown (ie, power-down) mode.
> + * So we do not have much to do here.
> + */
> + chip->suspended = true;
> +
> + mutex_unlock(&chip->lock);
> + return 0;
> +}
> +
> +static int isl29018_resume(struct device *dev)
> +{
> + struct isl29018_chip *chip = iio_priv(dev_get_drvdata(dev));
> + int err;
> +
> + mutex_lock(&chip->lock);
> +
> + err = isl29018_chip_init(chip);
> + if (!err)
> + chip->suspended = false;
> +
> + mutex_unlock(&chip->lock);
> + return err;
> +}
> +
> +static SIMPLE_DEV_PM_OPS(isl29018_pm_ops, isl29018_suspend, isl29018_resume);
> +#define ISL29018_PM_OPS (&isl29018_pm_ops)
> +#else
> +#define ISL29018_PM_OPS NULL
> +#endif
> +
> static const struct i2c_device_id isl29018_id[] = {
> {"isl29018", 0},
> {}
> @@ -620,6 +664,7 @@ static struct i2c_driver isl29018_driver = {
> .class = I2C_CLASS_HWMON,
> .driver = {
> .name = "isl29018",
> + .pm = ISL29018_PM_OPS,
> .owner = THIS_MODULE,
> .of_match_table = isl29018_of_match,
> },
>