Adjust the initial reverse channel amplitude parsing from
firmware interface the 'maxim,reverse-channel-microvolt'
property.
This change is required for both rdacm20 and rdacm21 camera
modules to be correctly probed when used in combination with
the max9286 deserializer.
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@xxxxxxxxxxxxxxxx>
Signed-off-by: Jacopo Mondi <jacopo+renesas@xxxxxxxxxx>
---
drivers/media/i2c/max9286.c | 23 ++++++++++++++++++++++-
1 file changed, 22 insertions(+), 1 deletion(-)
diff --git a/drivers/media/i2c/max9286.c b/drivers/media/i2c/max9286.c
index 021309c6dd6f..9b40a4890c4d 100644
--- a/drivers/media/i2c/max9286.c
+++ b/drivers/media/i2c/max9286.c
@@ -163,6 +163,8 @@ struct max9286_priv {
unsigned int mux_channel;
bool mux_open;
+ u32 reverse_channel_mv;
+
struct v4l2_ctrl_handler ctrls;
struct v4l2_ctrl *pixelrate;
@@ -557,10 +559,14 @@ static int max9286_notify_bound(struct v4l2_async_notifier *notifier,
* All enabled sources have probed and enabled their reverse control
* channels:
*
+ * - Increase the reverse channel amplitude to compensate for the
+ * remote ends high threshold, if not done already
* - Verify all configuration links are properly detected
* - Disable auto-ack as communication on the control channel are now
* stable.
*/
+ if (priv->reverse_channel_mv < 170)
+ max9286_reverse_channel_setup(priv, 170);
max9286_check_config_link(priv, priv->source_mask);
/*
@@ -967,7 +973,7 @@ static int max9286_setup(struct max9286_priv *priv)
* only. This should be disabled after the mux is initialised.
*/
max9286_configure_i2c(priv, true);
- max9286_reverse_channel_setup(priv, 170);
+ max9286_reverse_channel_setup(priv, priv->reverse_channel_mv);
/*
* Enable GMSL links, mask unused ones and autodetect link
@@ -1131,6 +1137,7 @@ static int max9286_parse_dt(struct max9286_priv *priv)
struct device_node *i2c_mux;
struct device_node *node = NULL;
unsigned int i2c_mux_mask = 0;
+ u32 reverse_channel_microvolt;
/* Balance the of_node_put() performed by of_find_node_by_name(). */
of_node_get(dev->of_node);
@@ -1221,6 +1228,20 @@ static int max9286_parse_dt(struct max9286_priv *priv)
}
of_node_put(node);
+ /*
+ * Parse the initial value of the reverse channel amplitude from
+ * the firmware interface and convert it to millivolts.
+ *
+ * Default it to 170mV for backward compatibility with DTBs that do not
+ * provide the property.
+ */
+ if (of_property_read_u32(dev->of_node,
+ "maxim,reverse-channel-microvolt",
+ &reverse_channel_microvolt))
+ priv->reverse_channel_mv = 170;
+ else
+ priv->reverse_channel_mv = reverse_channel_microvolt / 1000U;
+
priv->route_mask = priv->source_mask;
return 0;
--
2.29.2
