From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-ea0-f176.google.com ([209.85.215.176]:65535 "EHLO mail-ea0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750992AbaAELGA (ORCPT ); Sun, 5 Jan 2014 06:06:00 -0500 Received: by mail-ea0-f176.google.com with SMTP id h14so7355926eaj.35 for ; Sun, 05 Jan 2014 03:05:59 -0800 (PST) Message-ID: <52C93CDB.1050202@googlemail.com> Date: Sun, 05 Jan 2014 12:07:07 +0100 From: =?ISO-8859-15?Q?Frank_Sch=E4fer?= MIME-Version: 1.0 To: Mauro Carvalho Chehab , unlisted-recipients:; CC: Linux Media Mailing List , Mauro Carvalho Chehab Subject: Re: [PATCH v4 09/22] [media] tvp5150: make read operations atomic References: <1388832951-11195-1-git-send-email-m.chehab@samsung.com> <1388832951-11195-10-git-send-email-m.chehab@samsung.com> In-Reply-To: <1388832951-11195-10-git-send-email-m.chehab@samsung.com> Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 8bit Sender: linux-media-owner@vger.kernel.org List-ID: Am 04.01.2014 11:55, schrieb Mauro Carvalho Chehab: > Instead of using two I2C operations between write and read, > use just one i2c_transfer. That allows I2C mutexes to not > let any other I2C transfer between the two. > > Signed-off-by: Mauro Carvalho Chehab > --- > drivers/media/i2c/tvp5150.c | 26 +++++++++++--------------- > 1 file changed, 11 insertions(+), 15 deletions(-) > > diff --git a/drivers/media/i2c/tvp5150.c b/drivers/media/i2c/tvp5150.c > index 89c0b13463b7..2ed05b67218b 100644 > --- a/drivers/media/i2c/tvp5150.c > +++ b/drivers/media/i2c/tvp5150.c > @@ -58,21 +58,17 @@ static int tvp5150_read(struct v4l2_subdev *sd, unsigned char addr) > struct i2c_client *c = v4l2_get_subdevdata(sd); > unsigned char buffer[1]; > int rc; > - > - buffer[0] = addr; > - > - rc = i2c_master_send(c, buffer, 1); > - if (rc < 0) { > - v4l2_err(sd, "i2c i/o error: rc == %d (should be 1)\n", rc); > - return rc; > - } > - > - msleep(10); > - > - rc = i2c_master_recv(c, buffer, 1); > - if (rc < 0) { > - v4l2_err(sd, "i2c i/o error: rc == %d (should be 1)\n", rc); > - return rc; > + struct i2c_msg msg[] = { > + { .addr = c->addr, .flags = 0, > + .buf = &addr, .len = 1 }, > + { .addr = c->addr, .flags = I2C_M_RD, > + .buf = buffer, .len = 1 } > + }; > + > + rc = i2c_transfer(c->adapter, msg, 2); > + if (rc < 0 || rc != 2) { > + v4l2_err(sd, "i2c i/o error: rc == %d (should be 2)\n", rc); > + return rc < 0 ? rc : -EIO; > } > > v4l2_dbg(2, debug, sd, "tvp5150: read 0x%02x = 0x%02x\n", addr, buffer[0]); Reviewed-by: Frank Schäfer Tested-by: Frank Schäfer