Re: [PATCH v3 5/7] iio: adc: exynos: Use input_device_enabled()

Michał Mirosław
2020-06-05T19:50:13Z

On Fri, Jun 05, 2020 at 07:33:33PM +0200, Andrzej Pietrasiewicz wrote:
> A new helper is available, so use it. Inspecting 'users' member of
> input_dev requires taking device's mutex.
>
> Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@collabora.com>
> ---
> drivers/iio/adc/exynos_adc.c | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iio/adc/exynos_adc.c b/drivers/iio/adc/exynos_adc.c
> index 22131a677445..294715bafe25 100644
> --- a/drivers/iio/adc/exynos_adc.c
> +++ b/drivers/iio/adc/exynos_adc.c
> @@ -630,10 +630,13 @@ static irqreturn_t exynos_ts_isr(int irq, void *dev_id)
> struct exynos_adc *info = dev_id;
> struct iio_dev *dev = dev_get_drvdata(info->dev);
> u32 x, y;
> - bool pressed;
> + bool pressed, cont;
> int ret;
>
> - while (info->input->users) {
> + mutex_lock(&info->input->mutex);
> + cont = input_device_enabled(info->input);
> + mutex_unlock(&info->input->mutex);
> + while (cont) {
> ret = exynos_read_s3c64xx_ts(dev, &x, &y);
> if (ret == -ETIMEDOUT)
> break;
> @@ -651,6 +654,10 @@ static irqreturn_t exynos_ts_isr(int irq, void *dev_id)
> input_sync(info->input);
>
> usleep_range(1000, 1100);
> +
> + mutex_lock(&info->input->mutex);
> + cont = input_device_enabled(info->input);
> + mutex_unlock(&info->input->mutex);
> }

The mutex doesn't really protect anything here, but I would nevertheless
suggest this sequence instead:

lock()
while (test) {
unlock()
...
lock()
}
unlock()

Best Regards,
Michał Mirosław