Re: [PATCH 2/5] iio: adc: palmas_gpadc: Replace indio_dev->mlock with own device lock

Jonathan Cameron
2021-02-21T16:39:41Z

On Mon, 28 Sep 2020 16:13:30 +0300
Mircea Caprioru <mircea.caprioru@analog.com> wrote:

> From: Sergiu Cuciurean <sergiu.cuciurean@analog.com>
>
> As part of the general cleanup of indio_dev->mlock, this change replaces
> it with a local lock on the device's state structure.
>
> This is part of a bigger cleanup.
> Link: https://lore.kernel.org/linux-iio/CA+U=Dsoo6YABe5ODLp+eFNPGFDjk5ZeQEceGkqjxXcVEhLWubw@mail.gmail.com/
>
> Signed-off-by: Sergiu Cuciurean <sergiu.cuciurean@analog.com>
> Signed-off-by: Mircea Caprioru <mircea.caprioru@analog.com>
Applied,

Thanks,

Jonathan

> ---
> drivers/iio/adc/palmas_gpadc.c | 16 +++++++++++++---
> 1 file changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iio/adc/palmas_gpadc.c b/drivers/iio/adc/palmas_gpadc.c
> index 889b88768b63..14874f11614d 100644
> --- a/drivers/iio/adc/palmas_gpadc.c
> +++ b/drivers/iio/adc/palmas_gpadc.c
> @@ -90,6 +90,12 @@ static struct palmas_gpadc_info palmas_gpadc_info[] = {
> * 3: 800 uA
> * @extended_delay: enable the gpadc extended delay mode
> * @auto_conversion_period: define the auto_conversion_period
> + * @lock: Lock to protect the device state during a potential concurrent
> + * read access from userspace. Reading a raw value requires a sequence
> + * of register writes, then a wait for a completion callback,
> + * and finally a register read, during which userspace could issue
> + * another read request. This lock protects a read access from
> + * ocurring before another one has finished.
> *
> * This is the palmas_gpadc structure to store run-time information
> * and pointers for this driver instance.
> @@ -110,6 +116,7 @@ struct palmas_gpadc {
> bool wakeup1_enable;
> bool wakeup2_enable;
> int auto_conversion_period;
> + struct mutex lock;
> };
>
> /*
> @@ -388,7 +395,7 @@ static int palmas_gpadc_read_raw(struct iio_dev *indio_dev,
> if (adc_chan > PALMAS_ADC_CH_MAX)
> return -EINVAL;
>
> - mutex_lock(&indio_dev->mlock);
> + mutex_lock(&adc->lock);
>
> switch (mask) {
> case IIO_CHAN_INFO_RAW:
> @@ -414,12 +421,12 @@ static int palmas_gpadc_read_raw(struct iio_dev *indio_dev,
> goto out;
> }
>
> - mutex_unlock(&indio_dev->mlock);
> + mutex_unlock(&adc->lock);
> return ret;
>
> out:
> palmas_gpadc_read_done(adc, adc_chan);
> - mutex_unlock(&indio_dev->mlock);
> + mutex_unlock(&adc->lock);
>
> return ret;
> }
> @@ -516,6 +523,9 @@ static int palmas_gpadc_probe(struct platform_device *pdev)
> adc->dev = &pdev->dev;
> adc->palmas = dev_get_drvdata(pdev->dev.parent);
> adc->adc_info = palmas_gpadc_info;
> +
> + mutex_init(&adc->lock);
> +
> init_completion(&adc->conv_completion);
> dev_set_drvdata(&pdev->dev, indio_dev);
>