[v2] em28xx: simplify ID-reading from Micron sensors
Commit Message
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>
Acked-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
---
drivers/media/usb/em28xx/em28xx-camera.c | 28 ++++------------------------
1 file changed, 4 insertions(+), 24 deletions(-)
@@ -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 */