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From: Jacopo Mondi <jacopo+renesas@jmondi.org>
To: Hans Verkuil <hverkuil-cisco@xs4all.nl>,
	kieran.bingham+renesas@ideasonboard.com,
	laurent.pinchart+renesas@ideasonboard.com,
	niklas.soderlund+renesas@ragnatech.se, geert@linux-m68k.org
Cc: Jacopo Mondi <jacopo+renesas@jmondi.org>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	linux-media@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Subject: [PATCH v5 11/15] media: i2c: rdacm20: Enable noise immunity
Date: Wed, 16 Jun 2021 14:46:12 +0200	[thread overview]
Message-ID: <20210616124616.49249-12-jacopo+renesas@jmondi.org> (raw)
In-Reply-To: <20210616124616.49249-1-jacopo+renesas@jmondi.org>

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 <jacopo+renesas@jmondi.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@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 c1a717153303..5e0314a2b1ca 100644
--- a/drivers/media/i2c/rdacm20.c
+++ b/drivers/media/i2c/rdacm20.c
@@ -539,7 +539,19 @@ static int rdacm20_initialize(struct rdacm20_device *dev)
 
 	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)
-- 
2.31.1


  parent reply	other threads:[~2021-06-16 12:46 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-16 12:46 [PATCH v5 00/15] media: gmsl: Reliability improvements Jacopo Mondi
2021-06-16 12:46 ` [PATCH v5 01/15] media: i2c: max9286: Adjust parameters indent Jacopo Mondi
2021-06-16 12:46 ` [PATCH v5 02/15] media: i2c: max9286: Rename reverse_channel_mv Jacopo Mondi
2021-06-16 12:46 ` [PATCH v5 03/15] media: i2c: max9286: Cache channel amplitude Jacopo Mondi
2021-06-16 12:46 ` [PATCH v5 04/15] media: i2c: max9286: Define high " Jacopo Mondi
2021-06-16 12:46 ` [PATCH v5 05/15] media: i2c: max9286: Rework comments in .bound() Jacopo Mondi
2021-06-16 12:46 ` [PATCH v5 06/15] media: i2c: max9271: Check max9271_write() return Jacopo Mondi
2021-06-16 12:46 ` [PATCH v5 07/15] media: i2c: max9271: Introduce wake_up() function Jacopo Mondi
2021-06-16 12:46 ` [PATCH v5 08/15] media: i2c: rdacm21: Add delay after OV490 reset Jacopo Mondi
2021-06-16 12:46 ` [PATCH v5 09/15] media: i2c: rdacm21: Fix OV10640 powerup Jacopo Mondi
2021-06-16 12:46 ` [PATCH v5 10/15] media: i2c: rdacm21: Power up OV10640 before OV490 Jacopo Mondi
2021-06-16 23:47   ` Kieran Bingham
2021-06-16 12:46 ` Jacopo Mondi [this message]
2021-06-16 12:46 ` [PATCH v5 12/15] media: i2c: rdacm20: Embed 'serializer' field Jacopo Mondi
2021-06-17  0:14   ` Laurent Pinchart
2021-06-17  6:18     ` Hans Verkuil
2021-06-17  7:42       ` Jacopo Mondi
2021-06-17  8:12         ` Hans Verkuil
2021-06-17  8:20           ` Jacopo Mondi
2021-06-16 12:46 ` [PATCH v5 13/15] media: i2c: rdacm20: Report camera module name Jacopo Mondi
2021-06-16 12:46 ` [PATCH v5 14/15] media: i2c: rdacm20: Check return values Jacopo Mondi
2021-06-16 12:46 ` [PATCH v5 15/15] media: i2c: rdacm20: Re-work ov10635 reset Jacopo Mondi

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