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[109.90.213.36]) by smtp.googlemail.com with ESMTPSA id j32sm10996200wre.67.2017.04.16.10.42.09 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Sun, 16 Apr 2017 10:42:09 -0700 (PDT) From: =?UTF-8?q?Frank=20Sch=C3=A4fer?= To: linux-media@vger.kernel.org Cc: mchehab@kernel.org, arnd@arndb.de, =?UTF-8?q?Frank=20Sch=C3=A4fer?= Subject: [PATCH v2] em28xx: simplify ID-reading from Micron sensors Date: Sun, 16 Apr 2017 19:41:52 +0200 Message-Id: <20170416174152.4416-1-fschaefer.oss@googlemail.com> X-Mailer: git-send-email 2.12.2 MIME-Version: 1.0 Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org X-PMX-Version: 6.0.0.2142326, Antispam-Engine: 2.7.2.2107409, Antispam-Data: 2017.4.16.173617 X-PMX-Spam: Gauge=IIIIIIII, Probability=8%, Report=' MULTIPLE_RCPTS 0.1, HTML_00_01 0.05, HTML_00_10 0.05, BODYTEXTP_SIZE_3000_LESS 0, BODY_SIZE_2000_2999 0, BODY_SIZE_5000_LESS 0, BODY_SIZE_7000_LESS 0, CT_TEXT_PLAIN_UTF8_CAPS 0, DKIM_SIGNATURE 0, NO_URI_HTTPS 0, __ANY_URI 0, __CC_NAME 0, __CC_NAME_DIFF_FROM_ACC 0, __CC_REAL_NAMES 0, __CT 0, __CTE 0, __CT_TEXT_PLAIN 0, __FRAUD_BODY_WEBMAIL 0, __FRAUD_WEBMAIL 0, __FRAUD_WEBMAIL_FROM 0, __FROM_DOMAIN_IN_ANY_CC2 0, __FROM_DOMAIN_IN_RCPT 0, __HAS_CC_HDR 0, __HAS_FROM 0, __HAS_LIST_ID 0, __HAS_MSGID 0, __HAS_X_MAILER 0, __HAS_X_MAILING_LIST 0, __MIME_TEXT_ONLY 0, __MIME_TEXT_P 0, __MIME_TEXT_P1 0, __MIME_VERSION 0, __MULTIPLE_RCPTS_CC_X2 0, __NO_HTML_TAG_RAW 0, __PHISH_SPEAR_STRUCTURE_1 0, __SANE_MSGID 0, __STOCK_PHRASE_7 0, __SUBJ_ALPHA_END 0, __TO_MALFORMED_2 0, __TO_NO_NAME 0, __URI_NO_WWW 0, __URI_NS , __YOUTUBE_RCVD 0' Use i2c_smbus_read_word_data() instead of i2c_master_send() and i2c_master_recv() for reading the ID of Micorn sensors. i2c_smbus_read_word_data() assumes that byes are in little-endian, so, it uses: data->word = msgbuf1[0] | (msgbuf1[1] << 8); However, Micron datasheet describes the ID as if they were read in big-endian. So, we need to change the byte order in order to match the ID number as described on their datasheets. Signed-off-by: Frank Schäfer Acked-by: Mauro Carvalho Chehab --- drivers/media/usb/em28xx/em28xx-camera.c | 28 ++++------------------------ 1 file changed, 4 insertions(+), 24 deletions(-) diff --git a/drivers/media/usb/em28xx/em28xx-camera.c b/drivers/media/usb/em28xx/em28xx-camera.c index 95eaa55356a9..ae87dd3e671f 100644 --- a/drivers/media/usb/em28xx/em28xx-camera.c +++ b/drivers/media/usb/em28xx/em28xx-camera.c @@ -97,8 +97,6 @@ static int em28xx_probe_sensor_micron(struct em28xx *dev) { int ret, i; char *name; - u8 reg; - __be16 id_be; u16 id; struct i2c_client *client = &dev->i2c_client[dev->def_i2c_bus]; @@ -106,10 +104,8 @@ static int em28xx_probe_sensor_micron(struct em28xx *dev) dev->em28xx_sensor = EM28XX_NOSENSOR; for (i = 0; micron_sensor_addrs[i] != I2C_CLIENT_END; i++) { client->addr = micron_sensor_addrs[i]; - /* NOTE: i2c_smbus_read_word_data() doesn't work with BE data */ /* Read chip ID from register 0x00 */ - reg = 0x00; - ret = i2c_master_send(client, ®, 1); + ret = i2c_smbus_read_word_data(client, 0x00); /* assumes LE */ if (ret < 0) { if (ret != -ENXIO) dev_err(&dev->intf->dev, @@ -117,24 +113,9 @@ static int em28xx_probe_sensor_micron(struct em28xx *dev) client->addr << 1, ret); continue; } - ret = i2c_master_recv(client, (u8 *)&id_be, 2); - if (ret < 0) { - dev_err(&dev->intf->dev, - "couldn't read from i2c device 0x%02x: error %i\n", - client->addr << 1, ret); - continue; - } - id = be16_to_cpu(id_be); + id = swab16(ret); /* LE -> BE */ /* Read chip ID from register 0xff */ - reg = 0xff; - ret = i2c_master_send(client, ®, 1); - if (ret < 0) { - dev_err(&dev->intf->dev, - "couldn't read from i2c device 0x%02x: error %i\n", - client->addr << 1, ret); - continue; - } - ret = i2c_master_recv(client, (u8 *)&id_be, 2); + ret = i2c_smbus_read_word_data(client, 0xff); if (ret < 0) { dev_err(&dev->intf->dev, "couldn't read from i2c device 0x%02x: error %i\n", @@ -142,10 +123,9 @@ static int em28xx_probe_sensor_micron(struct em28xx *dev) continue; } /* Validate chip ID to be sure we have a Micron device */ - if (id != be16_to_cpu(id_be)) + if (id != swab16(ret)) continue; /* Check chip ID */ - id = be16_to_cpu(id_be); switch (id) { case 0x1222: name = "MT9V012"; /* MI370 */ /* 640x480 */