From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f196.google.com ([209.85.192.196]:39386 "EHLO mail-pf0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752630AbeDPCwQ (ORCPT ); Sun, 15 Apr 2018 22:52:16 -0400 From: Akinobu Mita Subject: [PATCH v2 01/10] media: ov772x: allow i2c controllers without I2C_FUNC_PROTOCOL_MANGLING Date: Mon, 16 Apr 2018 11:51:42 +0900 Message-Id: <1523847111-12986-2-git-send-email-akinobu.mita@gmail.com> In-Reply-To: <1523847111-12986-1-git-send-email-akinobu.mita@gmail.com> References: <1523847111-12986-1-git-send-email-akinobu.mita@gmail.com> Sender: devicetree-owner@vger.kernel.org To: linux-media@vger.kernel.org, devicetree@vger.kernel.org Cc: Akinobu Mita , Jacopo Mondi , Laurent Pinchart , Hans Verkuil , Sakari Ailus , Mauro Carvalho Chehab List-ID: 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: Jacopo Mondi Cc: Laurent Pinchart Cc: Hans Verkuil Cc: Sakari Ailus Cc: Mauro Carvalho Chehab Signed-off-by: Akinobu Mita --- * v2 - Replace the implementation of ov772x_read() instead of adding an alternative method drivers/media/i2c/ov772x.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-) diff --git a/drivers/media/i2c/ov772x.c b/drivers/media/i2c/ov772x.c index b62860c..7e79da0 100644 --- a/drivers/media/i2c/ov772x.c +++ b/drivers/media/i2c/ov772x.c @@ -542,9 +542,19 @@ static struct ov772x_priv *to_ov772x(struct v4l2_subdev *sd) 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) @@ -1255,10 +1265,9 @@ static int ov772x_probe(struct i2c_client *client, 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; -- 2.7.4