Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752192AbbDZSkR (ORCPT ); Sun, 26 Apr 2015 14:40:17 -0400 Received: from saturn.retrosnub.co.uk ([178.18.118.26]:42477 "EHLO saturn.retrosnub.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751194AbbDZSkP (ORCPT ); Sun, 26 Apr 2015 14:40:15 -0400 Message-ID: <553D310D.4010406@kernel.org> Date: Sun, 26 Apr 2015 19:40:13 +0100 From: Jonathan Cameron User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: Irina Tirdea , linux-iio@vger.kernel.org, Hartmut Knaack CC: linux-kernel@vger.kernel.org, Vlad Dogaru Subject: Re: [PATCH v2 01/17] iio: accel: mma9553: fix endianness issue when reading status References: <1428939664-12503-1-git-send-email-irina.tirdea@intel.com> <1428939664-12503-2-git-send-email-irina.tirdea@intel.com> In-Reply-To: <1428939664-12503-2-git-send-email-irina.tirdea@intel.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2007 Lines: 57 On 13/04/15 16:40, Irina Tirdea wrote: > Refactor code for simplicity and clarity. > > This also fixes an endianness issue with the original code. > When reading multiple registers, the received buffer of > 16-bytes words is little endian (status, step count). On > big endian machines, casting them to u32 would result in > reversed order in the buffer (step count, status) leading > to incorrect values for step count and activity. > > Signed-off-by: Irina Tirdea > Reported-by: Hartmut Knaack Applied to the fixes-togreg branch of iio.git Thanks > --- > drivers/iio/accel/mma9553.c | 11 ++++------- > 1 file changed, 4 insertions(+), 7 deletions(-) > > diff --git a/drivers/iio/accel/mma9553.c b/drivers/iio/accel/mma9553.c > index 2df1af7..607dbfc 100644 > --- a/drivers/iio/accel/mma9553.c > +++ b/drivers/iio/accel/mma9553.c > @@ -316,22 +316,19 @@ static int mma9553_set_config(struct mma9553_data *data, u16 reg, > static int mma9553_read_activity_stepcnt(struct mma9553_data *data, > u8 *activity, u16 *stepcnt) > { > - u32 status_stepcnt; > - u16 status; > + u16 buf[2]; > int ret; > > ret = mma9551_read_status_words(data->client, MMA9551_APPID_PEDOMETER, > - MMA9553_REG_STATUS, sizeof(u32), > - (u16 *) &status_stepcnt); > + MMA9553_REG_STATUS, sizeof(u32), buf); > if (ret < 0) { > dev_err(&data->client->dev, > "error reading status and stepcnt\n"); > return ret; > } > > - status = status_stepcnt & MMA9553_MASK_CONF_WORD; > - *activity = mma9553_get_bits(status, MMA9553_MASK_STATUS_ACTIVITY); > - *stepcnt = status_stepcnt >> 16; > + *activity = mma9553_get_bits(buf[0], MMA9553_MASK_STATUS_ACTIVITY); > + *stepcnt = buf[1]; > > return 0; > } > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/