On Thu, Oct 18, 2018 at 12:10:32PM +0300, Stefan Popa wrote:
> +static int ad7606_read_samples(struct ad7606_state *st)
> +{
> +     unsigned int num = st->chip_info->num_channels;
> +     u16 *data = st->data;
> +     int ret;
> +
> +     /*
> +      * The frstdata signal is set to high while and after reading the sample
> +      * of the first channel and low for all other channels. This can be used
> +      * to check that the incoming data is correctly aligned. During normal
> +      * operation the data should never become unaligned, but some glitch or
> +      * electrostatic discharge might cause an extra read or clock cycle.
> +      * Monitoring the frstdata signal allows to recover from such failure
> +      * situations.
> +      */
> +
> +     if (st->gpio_frstdata) {
> +             ret = st->bops->read_block(st->dev, 1, data);
> +             if (ret)
> +                     return ret;
> +
> +             if (!gpiod_get_value(st->gpio_frstdata)) {

This check should maybe be:

                if (gpiod_get_value(st->gpio_frstdata) <= 0) {

(Or possibly not, I don't know the code very well).

> +                     ad7606_reset(st);
> +                     return -EIO;
> +             }
> +
> +             data++;
> +             num--;
> +     }
> +
> +     return st->bops->read_block(st->dev, num, data);
> +}

regards,
dan carpenter
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