From 09741de09bf8a05558c37b2bbd85ca8f516fb753 Mon Sep 17 00:00:00 2001 From: Jacopo Mondi Date: Wed, 16 Jun 2021 14:46:12 +0200 Subject: [PATCH] media: i2c: rdacm20: Enable noise immunity 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. Signed-off-by: Jacopo Mondi Reviewed-by: Laurent Pinchart Reviewed-by: Kieran Bingham Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- 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 91b9b68..9d5de15 100644 --- a/drivers/media/i2c/rdacm20.c +++ b/drivers/media/i2c/rdacm20.c @@ -539,7 +539,19 @@ again: 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 int rdacm20_probe(struct i2c_client *client) -- 2.7.4