[Linux-stm32] [PATCH 2/5] iio: stmpe-adc: Reinit completion struct on begin conversion

[Jonathan Cameron]

On Tue,  7 May 2019 16:36:12 +0200
Philippe Schenker <dev at pschenker.ch> wrote:

> From: Philippe Schenker <philippe.schenker at toradex.com>
> 
> In some cases, the wait_completion got interrupted. This caused the
> error-handling to mutex_unlock the function. The before turned on
> interrupt then got called anyway. In the ISR then completion() was
> called causing wrong adc-values returned in a following adc-readout.
> 
> Reinitialise completion struct to make sure the counter is zero
> when beginning a new adc-conversion.
> 
> Signed-off-by: Philippe Schenker <philippe.schenker at toradex.com>
Hi Philippe, 

To me this looks like a fix that we should consider applying to stable.
However, as it is in the middle of this series I'm not going to take
it via the fast route (during rc's). If people want to backport it
they will have to wait until after the next merge window.
If anyone has an urgent need, then shout in the next week and I'll
pull this version out and we can restructure the set.

Applied to the togreg branch of iio.git and pushed out as testing
for the autobuilders to play with it.

Thanks,

Jonathan

> ---
> 
>  drivers/iio/adc/stmpe-adc.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/iio/adc/stmpe-adc.c b/drivers/iio/adc/stmpe-adc.c
> index 9ec338ba3440..b3872eb37293 100644
> --- a/drivers/iio/adc/stmpe-adc.c
> +++ b/drivers/iio/adc/stmpe-adc.c
> @@ -65,6 +65,8 @@ static int stmpe_read_voltage(struct stmpe_adc *info,
>  
>  	mutex_lock(&info->lock);
>  
> +	reinit_completion(&info->completion);
> +
>  	info->channel = (u8)chan->channel;
>  
>  	if (info->channel > STMPE_ADC_LAST_NR) {
> @@ -105,6 +107,8 @@ static int stmpe_read_temp(struct stmpe_adc *info,
>  
>  	mutex_lock(&info->lock);
>  
> +	reinit_completion(&info->completion);
> +
>  	info->channel = (u8)chan->channel;
>  
>  	if (info->channel != STMPE_TEMP_CHANNEL) {