diff mbox series

[v3,14/19] media: i2c: rdacm20: Enable noise immunity

Message ID 20210319164148.199192-15-jacopo+renesas@jmondi.org (mailing list archive)
State New
Delegated to: Kieran Bingham
Headers show
Series media: gmsl: Reliability improvement | expand

Commit Message

Jacopo Mondi March 19, 2021, 4:41 p.m. UTC 
Enable the noise immunity threshold at the end of the rdacm20
initialization routine.

The rdacm20 camera module has been so far tested with a startup
delay that allowed the embedded MCU to program the serializer. If
the initialization routine is run before the MCU programs the
serializer and the image sensor and their addresses gets changed
by the rdacm20 driver it is required to manually enable the noise
immunity threshold to make the communication on the control channel
more reliable.

Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
---
 drivers/media/i2c/rdacm20.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

Comments

Laurent Pinchart March 20, 2021, 4:16 p.m. UTC | #1 
Hi Jacopo,

Thank you for the patch.

On Fri, Mar 19, 2021 at 05:41:43PM +0100, Jacopo Mondi wrote:
> Enable the noise immunity threshold at the end of the rdacm20
> initialization routine.
> 
> The rdacm20 camera module has been so far tested with a startup
> delay that allowed the embedded MCU to program the serializer. If
> the initialization routine is run before the MCU programs the
> serializer and the image sensor and their addresses gets changed
> by the rdacm20 driver it is required to manually enable the noise
> immunity threshold to make the communication on the control channel
> more reliable.
> 
> Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
> Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> ---
>  drivers/media/i2c/rdacm20.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/media/i2c/rdacm20.c b/drivers/media/i2c/rdacm20.c
> index 2881e752efbe..554fd3b3ec3d 100644
> --- a/drivers/media/i2c/rdacm20.c
> +++ b/drivers/media/i2c/rdacm20.c
> @@ -518,7 +518,19 @@ static int rdacm20_init(struct v4l2_subdev *sd, unsigned int val)
>  
>  	dev_info(dev->dev, "Identified MAX9271 + OV10635 device\n");
>  
> -	return 0;
> +	/*
> +	 * Set reverse channel high threshold to increase noise immunity.
> +	 *
> +	 * This should be compensated by increasing the reverse channel
> +	 * amplitude on the remote deserializer side.
> +	 *
> +	 * TODO Inspect the embedded MCU programming sequence to make sure
> +	 * there are no conflicts with the configuration applied here.
> +	 *
> +	 * TODO Clarify the embedded MCU startup delay to avoid write
> +	 * collisions on the I2C bus.
> +	 */
> +	return max9271_set_high_threshold(&dev->serializer, true);
>  }
>  
>  static const struct v4l2_subdev_core_ops rdacm20_core_ops = {
diff mbox series

Patch

diff --git a/drivers/media/i2c/rdacm20.c b/drivers/media/i2c/rdacm20.c
index 2881e752efbe..554fd3b3ec3d 100644
--- a/drivers/media/i2c/rdacm20.c
+++ b/drivers/media/i2c/rdacm20.c
@@ -518,7 +518,19 @@  static int rdacm20_init(struct v4l2_subdev *sd, unsigned int val)
 
 	dev_info(dev->dev, "Identified MAX9271 + OV10635 device\n");
 
-	return 0;
+	/*
+	 * Set reverse channel high threshold to increase noise immunity.
+	 *
+	 * This should be compensated by increasing the reverse channel
+	 * amplitude on the remote deserializer side.
+	 *
+	 * TODO Inspect the embedded MCU programming sequence to make sure
+	 * there are no conflicts with the configuration applied here.
+	 *
+	 * TODO Clarify the embedded MCU startup delay to avoid write
+	 * collisions on the I2C bus.
+	 */
+	return max9271_set_high_threshold(&dev->serializer, true);
 }
 
 static const struct v4l2_subdev_core_ops rdacm20_core_ops = {