Hi Jacopo,
On 12/11/2020 16:27, Jacopo Mondi wrote:
> Adjust the initial reverse channel amplitude parsing from
> firmware interface the 'maxim,initial-reverse-channel-mV'
> property.
>
> This change is required for both rdacm20 and rdacm21 camera
> modules to be correctly probed when used in combination with
> the max9286 deserializer.
>
> Signed-off-by: Jacopo Mondi <jacopo+renesas@xxxxxxxxxx>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@xxxxxxxxxxxxxxxx>
> ---
> drivers/media/i2c/max9286.c | 20 +++++++++++++++++++-
> 1 file changed, 19 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/media/i2c/max9286.c b/drivers/media/i2c/max9286.c
> index 31e27d0f34f1..11ba047f3793 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
> @@ -1235,6 +1241,18 @@ 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.
> + *
> + * Default it to 170mV for backward compatibility with DTB that do not
> + * provide the property.
> + */
> + if (of_property_read_u32(dev->of_node,
> + "maxim,initial-reverse-channel-mV",
> + &priv->reverse_channel_mV))
> + priv->reverse_channel_mV = 170;
> +
> priv->route_mask = priv->source_mask;
>
> return 0;
>
