Commit 4d584436 authored by Frank Schaefer's avatar Frank Schaefer Committed by Mauro Carvalho Chehab
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[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: default avatarFrank Schäfer <fschaefer.oss@googlemail.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@s-opensource.com>
parent e7080d44

drivers/media/usb/em28xx/em28xx-camera.c

+4 −24
Original line number Diff line number Diff line
@@ -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 */

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