iio: adc: ad7606: fix oversampling gpio array

gpiod_set_array_value was misused here: the implementation relied on the
assumption that an unsigned long was required for each gpio, while the
function expects a bit array stored in "as much unsigned long as needed
for storing one bit per GPIO", i.e it is using a bit field.

This leaded to incorrect parameter passed to gpiod_set_array_value, that
would set 1 value instead of 3.
It also prevents to select the software mode correctly for the AD7606B.

Fixes: d2a415c8 ("iio: adc: ad7606: Add support for AD7606B ADC")
Fixes: 41f71e5e ("staging: iio: adc: ad7606: Use find_closest() macro")
Signed-off-by: Guillaume Stols <gstols@baylibre.com>
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/ad7606.c

@@ -236,9 +236,9 @@ static int ad7606_write_os_hw(struct iio_dev *indio_dev, int val)
 	struct ad7606_state *st = iio_priv(indio_dev);
 	DECLARE_BITMAP(values, 3);
 
-	values[0] = val;
+	values[0] = val & GENMASK(2, 0);
 
-	gpiod_set_array_value(ARRAY_SIZE(values), st->gpio_os->desc,
+	gpiod_set_array_value(st->gpio_os->ndescs, st->gpio_os->desc,
 			      st->gpio_os->info, values);
 
 	/* AD7616 requires a reset to update value */

drivers/iio/adc/ad7606_spi.c

@@ -249,8 +249,9 @@ static int ad7616_sw_mode_config(struct iio_dev *indio_dev)
 static int ad7606B_sw_mode_config(struct iio_dev *indio_dev)
 {
 	struct ad7606_state *st = iio_priv(indio_dev);
-	unsigned long os[3] = {1};
+	DECLARE_BITMAP(os, 3);
 
+	bitmap_fill(os, 3);
 	/*
 	 * Software mode is enabled when all three oversampling
 	 * pins are set to high. If oversampling gpios are defined
@@ -258,7 +259,7 @@ static int ad7606B_sw_mode_config(struct iio_dev *indio_dev)
 	 * otherwise, they must be hardwired to VDD
 	 */
 	if (st->gpio_os) {
-		gpiod_set_array_value(ARRAY_SIZE(os),
+		gpiod_set_array_value(st->gpio_os->ndescs,
 				      st->gpio_os->desc, st->gpio_os->info, os);
 	}
 	/* OS of 128 and 256 are available only in software mode */