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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 07/15] media: i2c: max9271: Introduce wake_up() function
Date: Wed, 16 Jun 2021 14:46:08 +0200	[thread overview]
Message-ID: <20210616124616.49249-8-jacopo+renesas@jmondi.org> (raw)
In-Reply-To: <20210616124616.49249-1-jacopo+renesas@jmondi.org>

The MAX9271 chip manual prescribes a delay of 5 milliseconds
after the chip exits from low power state.

Add a new function to the max9271 library driver that wakes up the chip
with a dummy i2c transaction and implements the correct delay of 5
milliseconds after the chip exits from low power state.

Use the newly introduced function in the rdacm20 and rdacm21 camera
drivers. The former was not respecting the required delay while the
latter was waiting for a too-short timeout.

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/max9271.c | 12 ++++++++++++
 drivers/media/i2c/max9271.h |  9 +++++++++
 drivers/media/i2c/rdacm20.c |  4 +---
 drivers/media/i2c/rdacm21.c |  5 +----
 4 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/drivers/media/i2c/max9271.c b/drivers/media/i2c/max9271.c
index 2c7dc7fb9846..ff86c8c4ea61 100644
--- a/drivers/media/i2c/max9271.c
+++ b/drivers/media/i2c/max9271.c
@@ -80,6 +80,18 @@ static int max9271_pclk_detect(struct max9271_device *dev)
 	return -EIO;
 }
 
+void max9271_wake_up(struct max9271_device *dev)
+{
+	/*
+	 * Use the chip default address as this function has to be called
+	 * before any other one.
+	 */
+	dev->client->addr = MAX9271_DEFAULT_ADDR;
+	i2c_smbus_read_byte(dev->client);
+	usleep_range(5000, 8000);
+}
+EXPORT_SYMBOL_GPL(max9271_wake_up);
+
 int max9271_set_serial_link(struct max9271_device *dev, bool enable)
 {
 	int ret;
diff --git a/drivers/media/i2c/max9271.h b/drivers/media/i2c/max9271.h
index d78fb21441e9..dc5e4e70ba6f 100644
--- a/drivers/media/i2c/max9271.h
+++ b/drivers/media/i2c/max9271.h
@@ -85,6 +85,15 @@ struct max9271_device {
 	struct i2c_client *client;
 };
 
+/**
+ * max9271_wake_up() - Wake up the serializer by issuing an i2c transaction
+ * @dev: The max9271 device
+ *
+ * This function shall be called before any other interaction with the
+ * serializer.
+ */
+void max9271_wake_up(struct max9271_device *dev);
+
 /**
  * max9271_set_serial_link() - Enable/disable serial link
  * @dev: The max9271 device
diff --git a/drivers/media/i2c/rdacm20.c b/drivers/media/i2c/rdacm20.c
index 90eb73f0e6e9..c1a717153303 100644
--- a/drivers/media/i2c/rdacm20.c
+++ b/drivers/media/i2c/rdacm20.c
@@ -455,9 +455,7 @@ static int rdacm20_initialize(struct rdacm20_device *dev)
 	unsigned int retry = 3;
 	int ret;
 
-	/* Verify communication with the MAX9271: ping to wakeup. */
-	dev->serializer->client->addr = MAX9271_DEFAULT_ADDR;
-	i2c_smbus_read_byte(dev->serializer->client);
+	max9271_wake_up(dev->serializer);
 
 	/* Serial link disabled during config as it needs a valid pixel clock. */
 	ret = max9271_set_serial_link(dev->serializer, false);
diff --git a/drivers/media/i2c/rdacm21.c b/drivers/media/i2c/rdacm21.c
index 179d107f494c..553e3f03752b 100644
--- a/drivers/media/i2c/rdacm21.c
+++ b/drivers/media/i2c/rdacm21.c
@@ -450,10 +450,7 @@ static int rdacm21_initialize(struct rdacm21_device *dev)
 {
 	int ret;
 
-	/* Verify communication with the MAX9271: ping to wakeup. */
-	dev->serializer.client->addr = MAX9271_DEFAULT_ADDR;
-	i2c_smbus_read_byte(dev->serializer.client);
-	usleep_range(3000, 5000);
+	max9271_wake_up(&dev->serializer);
 
 	/* Enable reverse channel and disable the serial link. */
 	ret = max9271_set_serial_link(&dev->serializer, false);
-- 
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 ` Jacopo Mondi [this message]
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 ` [PATCH v5 15/15] media: i2c: rdacm20: Re-work ov10635 reset Jacopo Mondi

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