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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 15/15] media: i2c: rdacm20: Re-work ov10635 reset
Date: Wed, 16 Jun 2021 14:46:16 +0200	[thread overview]
Message-ID: <20210616124616.49249-16-jacopo+renesas@jmondi.org> (raw)
In-Reply-To: <20210616124616.49249-1-jacopo+renesas@jmondi.org>

The OV10635 image sensor embedded in the camera module is currently
reset after the MAX9271 initialization with two long delays that were
most probably not correctly characterized.

Re-work the image sensor reset procedure by holding the chip in reset
during the MAX9271 configuration, removing the long sleep delays and
only wait after the chip exits from reset for 350-500 microseconds
interval, which is larger than the minimum (2048 * (1 / XVCLK)) timeout
characterized in the chip manual.

Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
 drivers/media/i2c/rdacm20.c | 29 +++++++++++++++++------------
 1 file changed, 17 insertions(+), 12 deletions(-)

diff --git a/drivers/media/i2c/rdacm20.c b/drivers/media/i2c/rdacm20.c
index e6fed86a3281..cb725c2778c0 100644
--- a/drivers/media/i2c/rdacm20.c
+++ b/drivers/media/i2c/rdacm20.c
@@ -473,6 +473,19 @@ static int rdacm20_initialize(struct rdacm20_device *dev)
 	if (ret)
 		return ret;
 
+	/*
+	 * Hold OV10635 in reset during max9271 configuration. The reset signal
+	 * has to be asserted for at least 200 microseconds.
+	 */
+	ret = max9271_enable_gpios(&dev->serializer, MAX9271_GPIO1OUT);
+	if (ret)
+		return ret;
+
+	ret = max9271_clear_gpios(&dev->serializer, MAX9271_GPIO1OUT);
+	if (ret)
+		return ret;
+	usleep_range(200, 500);
+
 	ret = max9271_configure_gmsl_link(&dev->serializer);
 	if (ret)
 		return ret;
@@ -487,22 +500,14 @@ static int rdacm20_initialize(struct rdacm20_device *dev)
 	dev->serializer.client->addr = dev->addrs[0];
 
 	/*
-	 * Reset the sensor by cycling the OV10635 reset signal connected to the
-	 * MAX9271 GPIO1 and verify communication with the OV10635.
+	 * Release ov10635 from reset and initialize it. The image sensor
+	 * requires at least 2048 XVCLK cycles (85 micro-seconds at 24MHz)
+	 * before being available. Stay safe and wait up to 500 micro-seconds.
 	 */
-	ret = max9271_enable_gpios(&dev->serializer, MAX9271_GPIO1OUT);
-	if (ret)
-		return ret;
-
-	ret = max9271_clear_gpios(&dev->serializer, MAX9271_GPIO1OUT);
-	if (ret)
-		return ret;
-	usleep_range(10000, 15000);
-
 	ret = max9271_set_gpios(&dev->serializer, MAX9271_GPIO1OUT);
 	if (ret)
 		return ret;
-	usleep_range(10000, 15000);
+	usleep_range(100, 500);
 
 again:
 	ret = ov10635_read16(dev, OV10635_PID);
-- 
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 ` [PATCH v5 11/15] media: i2c: rdacm20: Enable noise immunity Jacopo Mondi
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 ` Jacopo Mondi [this message]

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