linux-kernel - [PATCH 4.18 073/228] media: ov772x: allow i2c controllers without I2C_FUNC_PROTOCOL

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Message-Id: <20181002132504.232798365@linuxfoundation.org>
Date:   Tue,  2 Oct 2018 06:22:50 -0700
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Hans Verkuil <hans.verkuil@...co.com>,
        Wolfram Sang <wsa@...-dreams.de>,
        Jacopo Mondi <jacopo+renesas@...ndi.org>,
        Akinobu Mita <akinobu.mita@...il.com>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        Mauro Carvalho Chehab <mchehab+samsung@...nel.org>,
        Sasha Levin <alexander.levin@...rosoft.com>
Subject: [PATCH 4.18 073/228] media: ov772x: allow i2c controllers without I2C_FUNC_PROTOCOL_MANGLING

4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Akinobu Mita <akinobu.mita@...il.com>

[ Upstream commit 0b964d183cbf3f95a062ad9f3eec87ffa2790558 ]

The ov772x driver only works when the i2c controller have
I2C_FUNC_PROTOCOL_MANGLING.  However, many i2c controller drivers don't
support it.

The reason that the ov772x requires I2C_FUNC_PROTOCOL_MANGLING is that
it doesn't support repeated starts.

This changes the reading ov772x register method so that it doesn't
require I2C_FUNC_PROTOCOL_MANGLING by calling two separated i2c messages.

Cc: Laurent Pinchart <laurent.pinchart@...asonboard.com>
Cc: Hans Verkuil <hans.verkuil@...co.com>
Cc: Wolfram Sang <wsa@...-dreams.de>
Reviewed-by: Jacopo Mondi <jacopo+renesas@...ndi.org>
Signed-off-by: Akinobu Mita <akinobu.mita@...il.com>
Signed-off-by: Sakari Ailus <sakari.ailus@...ux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@...nel.org>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/media/i2c/ov772x.c |   20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

--- a/drivers/media/i2c/ov772x.c
+++ b/drivers/media/i2c/ov772x.c
@@ -542,9 +542,19 @@ static struct ov772x_priv *to_ov772x(str
 	return container_of(sd, struct ov772x_priv, subdev);
 }
 
-static inline int ov772x_read(struct i2c_client *client, u8 addr)
+static int ov772x_read(struct i2c_client *client, u8 addr)
 {
-	return i2c_smbus_read_byte_data(client, addr);
+	int ret;
+	u8 val;
+
+	ret = i2c_master_send(client, &addr, 1);
+	if (ret < 0)
+		return ret;
+	ret = i2c_master_recv(client, &val, 1);
+	if (ret < 0)
+		return ret;
+
+	return val;
 }
 
 static inline int ov772x_write(struct i2c_client *client, u8 addr, u8 value)
@@ -1263,13 +1273,11 @@ static int ov772x_probe(struct i2c_clien
 		return -EINVAL;
 	}
 
-	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
-					      I2C_FUNC_PROTOCOL_MANGLING)) {
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
 		dev_err(&adapter->dev,
-			"I2C-Adapter doesn't support SMBUS_BYTE_DATA or PROTOCOL_MANGLING\n");
+			"I2C-Adapter doesn't support SMBUS_BYTE_DATA\n");
 		return -EIO;
 	}
-	client->flags |= I2C_CLIENT_SCCB;
 
 	priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)