[media] em28xx: simplify ID-reading from Micron sensors

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 <fschaefer.oss@googlemail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

diff --git a/drivers/media/usb/em28xx/em28xx-camera.c b/drivers/media/usb/em28xx/em28xx-camera.c
index 2f59237ee399ed683f219688affc014f3cca957d..f401e5aa13730d69e7d8d0d561a44d0b62051a5d 100644 (file)
--- a/drivers/media/usb/em28xx/em28xx-camera.c
+++ b/drivers/media/usb/em28xx/em28xx-camera.c
@@ -98,8 +98,6 @@ 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];
@@ -107,10 +105,8 @@ 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, &reg, 1);
+               ret = i2c_smbus_read_word_data(client, 0x00); /* assumes LE */
                if (ret < 0) {
                        if (ret != -ENXIO)
                                dev_err(&dev->intf->dev,
@@ -118,24 +114,9 @@ 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, &reg, 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",
@@ -143,10 +124,9 @@ 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 */