iio: adc: ad7124: Micro-optimize channel disabling

The key objective in ad7124_disable_one() is clearing the
AD7124_CHANNEL_EN_MSK bit in the channel register. However there is no
advantage to keep the other bits in that register because when the
channel is used next time, all fields are rewritten anyhow. So instead
of using ad7124_spi_write_mask() (which is a register read plus a
register write) use a simple register write clearing the complete
register.

Also do the same in the .disable_all() callback by using the
.disable_one() callback there.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Link: https://patch.msgid.link/20250120140708.1093655-2-u.kleine-koenig@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/adc/ad7124.c b/drivers/iio/adc/ad7124.c
index 6ae27cdd32503c6219cbd3d60036b403f3db9560..2fdeb32479522123668ff5c7f00a9c1f76ca3cdf 100644 (file)
--- a/drivers/iio/adc/ad7124.c
+++ b/drivers/iio/adc/ad7124.c
@@ -540,6 +540,14 @@ static int ad7124_append_status(struct ad_sigma_delta *sd, bool append)
        return 0;
 }
 
+static int ad7124_disable_one(struct ad_sigma_delta *sd, unsigned int chan)
+{
+       struct ad7124_state *st = container_of(sd, struct ad7124_state, sd);
+
+       /* The relevant thing here is that AD7124_CHANNEL_EN_MSK is cleared. */
+       return ad_sd_write_reg(&st->sd, AD7124_CHANNEL(chan), 2, 0);
+}
+
 static int ad7124_disable_all(struct ad_sigma_delta *sd)
 {
        struct ad7124_state *st = container_of(sd, struct ad7124_state, sd);
@@ -547,7 +555,7 @@ static int ad7124_disable_all(struct ad_sigma_delta *sd)
        int i;
 
        for (i = 0; i < st->num_channels; i++) {
-               ret = ad7124_spi_write_mask(st, AD7124_CHANNEL(i), AD7124_CHANNEL_EN_MSK, 0, 2);
+               ret = ad7124_disable_one(sd, i);
                if (ret < 0)
                        return ret;
        }
@@ -555,13 +563,6 @@ static int ad7124_disable_all(struct ad_sigma_delta *sd)
        return 0;
 }
 
-static int ad7124_disable_one(struct ad_sigma_delta *sd, unsigned int chan)
-{
-       struct ad7124_state *st = container_of(sd, struct ad7124_state, sd);
-
-       return ad7124_spi_write_mask(st, AD7124_CHANNEL(chan), AD7124_CHANNEL_EN_MSK, 0, 2);
-}
-
 static const struct ad_sigma_delta_info ad7124_sigma_delta_info = {
        .set_channel = ad7124_set_channel,
        .append_status = ad7124_append_status,