iio: adc: ad7606: Allow reconfigration after reset

According to datasheet, ad7616 require at least 15ms after a restart
to fully reconfigure and being able to receive new commands via spi.

Signed-off-by: Beniamin Bia <beniamin.bia@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/ad7606.c

@@ -594,6 +594,10 @@ int ad7606_probe(struct device *dev, int irq, void __iomem *base_address,
 	if (ret)
 		dev_warn(st->dev, "failed to RESET: no RESET GPIO specified\n");
 
+	/* AD7616 requires al least 15ms to reconfigure after a reset */
+	if (msleep_interruptible(15))
+		return -ERESTARTSYS;
+
 	st->write_scale = ad7606_write_scale_hw;
 	st->write_os = ad7606_write_os_hw;