media: i2c: max9286: Define high channel amplitude

Provide a macro to define the reverse channel amplitude to
be used to compensate the remote serializer noise immunity.

While at it, update a comment.

Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

diff --git a/drivers/media/i2c/max9286.c b/drivers/media/i2c/max9286.c
index 5336862..b0cd9fc 100644 (file)
--- a/drivers/media/i2c/max9286.c
+++ b/drivers/media/i2c/max9286.c
@@ -113,6 +113,7 @@
 #define MAX9286_REV_TRF(n)             ((n) << 4)
 #define MAX9286_REV_AMP(n)             ((((n) - 30) / 10) << 1) /* in mV */
 #define MAX9286_REV_AMP_X              BIT(0)
+#define MAX9286_REV_AMP_HIGH           170
 /* Register 0x3f */
 #define MAX9286_EN_REV_CFG             BIT(6)
 #define MAX9286_REV_FLEN(n)            ((n) - 20)
@@ -567,12 +568,12 @@ static int max9286_notify_bound(struct v4l2_async_notifier *notifier,
         * channels:
         *
         * - Increase the reverse channel amplitude to compensate for the
-        *   remote ends high threshold, if not done already
+        *   remote ends high threshold
         * - Verify all configuration links are properly detected
         * - Disable auto-ack as communication on the control channel are now
         *   stable.
         */
-       max9286_reverse_channel_setup(priv, 170);
+       max9286_reverse_channel_setup(priv, MAX9286_REV_AMP_HIGH);
        max9286_check_config_link(priv, priv->source_mask);
 
        /*