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Commit 9e006953 authored by Frank Schaefer's avatar Frank Schaefer Committed by Mauro Carvalho Chehab
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[media] em28xx: reduce stack usage in sensor probing functions 



It's no longer necessary to keep the i2c_client in the device struct
unmodified until a sensor is found, so reduce stack usage in
em28xx_probe_sensor_micron() and em28xx_probe_sensor_omnivision() by using
a pointer to the client instead of a local copy.

Reported-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarFrank Schäfer <fschaefer.oss@googlemail.com>
Signed-off-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@s-opensource.com>
parent 3b8b2e1c

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

+20 −22
Original line number Original line Diff line number Diff line
@@ -110,44 +110,44 @@ static int em28xx_probe_sensor_micron(struct em28xx *dev) 
	__be16 id_be;

	__be16 id_be;

	u16 id;

	u16 id;





	struct i2c_client client = dev->i2c_client[dev->def_i2c_bus];

	struct i2c_client *client = &dev->i2c_client[dev->def_i2c_bus];





	dev->em28xx_sensor = EM28XX_NOSENSOR;

	dev->em28xx_sensor = EM28XX_NOSENSOR;

	for (i = 0; micron_sensor_addrs[i] != I2C_CLIENT_END; i++) {

	for (i = 0; micron_sensor_addrs[i] != I2C_CLIENT_END; i++) {

		client.addr = micron_sensor_addrs[i];

		client->addr = micron_sensor_addrs[i];

		/* NOTE: i2c_smbus_read_word_data() doesn't work with BE data */

		/* NOTE: i2c_smbus_read_word_data() doesn't work with BE data */

		/* Read chip ID from register 0x00 */

		/* Read chip ID from register 0x00 */

		reg = 0x00;

		reg = 0x00;

		ret = i2c_master_send(&client, &reg, 1);

		ret = i2c_master_send(client, &reg, 1);

		if (ret < 0) {

		if (ret < 0) {

			if (ret != -ENXIO)

			if (ret != -ENXIO)

				dev_err(&dev->intf->dev,

				dev_err(&dev->intf->dev,

					"couldn't read from i2c device 0x%02x: error %i\n",

					"couldn't read from i2c device 0x%02x: error %i\n",

				       client.addr << 1, ret);

				       client->addr << 1, ret);

			continue;

			continue;

		}

		}

		ret = i2c_master_recv(&client, (u8 *)&id_be, 2);

		ret = i2c_master_recv(client, (u8 *)&id_be, 2);

		if (ret < 0) {

		if (ret < 0) {

			dev_err(&dev->intf->dev,

			dev_err(&dev->intf->dev,

				"couldn't read from i2c device 0x%02x: error %i\n",

				"couldn't read from i2c device 0x%02x: error %i\n",

				client.addr << 1, ret);

				client->addr << 1, ret);

			continue;

			continue;

		}

		}

		id = be16_to_cpu(id_be);

		id = be16_to_cpu(id_be);

		/* Read chip ID from register 0xff */

		/* Read chip ID from register 0xff */

		reg = 0xff;

		reg = 0xff;

		ret = i2c_master_send(&client, &reg, 1);

		ret = i2c_master_send(client, &reg, 1);

		if (ret < 0) {

		if (ret < 0) {

			dev_err(&dev->intf->dev,

			dev_err(&dev->intf->dev,

				"couldn't read from i2c device 0x%02x: error %i\n",

				"couldn't read from i2c device 0x%02x: error %i\n",

				client.addr << 1, ret);

				client->addr << 1, ret);

			continue;

			continue;

		}

		}

		ret = i2c_master_recv(&client, (u8 *)&id_be, 2);

		ret = i2c_master_recv(client, (u8 *)&id_be, 2);

		if (ret < 0) {

		if (ret < 0) {

			dev_err(&dev->intf->dev,

			dev_err(&dev->intf->dev,

				"couldn't read from i2c device 0x%02x: error %i\n",

				"couldn't read from i2c device 0x%02x: error %i\n",

				client.addr << 1, ret);

				client->addr << 1, ret);

			continue;

			continue;

		}

		}

		/* Validate chip ID to be sure we have a Micron device */

		/* Validate chip ID to be sure we have a Micron device */
@@ -197,7 +197,6 @@ static int em28xx_probe_sensor_micron(struct em28xx *dev) 
			dev_info(&dev->intf->dev,

			dev_info(&dev->intf->dev,

				 "sensor %s detected\n", name);

				 "sensor %s detected\n", name);





		dev->i2c_client[dev->def_i2c_bus].addr = client.addr;

		return 0;

		return 0;

	}

	}
@@ -213,30 +212,30 @@ static int em28xx_probe_sensor_omnivision(struct em28xx *dev) 
	char *name;

	char *name;

	u8 reg;

	u8 reg;

	u16 id;

	u16 id;

	struct i2c_client client = dev->i2c_client[dev->def_i2c_bus];

	struct i2c_client *client = &dev->i2c_client[dev->def_i2c_bus];





	dev->em28xx_sensor = EM28XX_NOSENSOR;

	dev->em28xx_sensor = EM28XX_NOSENSOR;

	/* NOTE: these devices have the register auto incrementation disabled

	/* NOTE: these devices have the register auto incrementation disabled

	 * by default, so we have to use single byte reads !              */

	 * by default, so we have to use single byte reads !              */

	for (i = 0; omnivision_sensor_addrs[i] != I2C_CLIENT_END; i++) {

	for (i = 0; omnivision_sensor_addrs[i] != I2C_CLIENT_END; i++) {

		client.addr = omnivision_sensor_addrs[i];

		client->addr = omnivision_sensor_addrs[i];

		/* Read manufacturer ID from registers 0x1c-0x1d (BE) */

		/* Read manufacturer ID from registers 0x1c-0x1d (BE) */

		reg = 0x1c;

		reg = 0x1c;

		ret = i2c_smbus_read_byte_data(&client, reg);

		ret = i2c_smbus_read_byte_data(client, reg);

		if (ret < 0) {

		if (ret < 0) {

			if (ret != -ENXIO)

			if (ret != -ENXIO)

				dev_err(&dev->intf->dev,

				dev_err(&dev->intf->dev,

					"couldn't read from i2c device 0x%02x: error %i\n",

					"couldn't read from i2c device 0x%02x: error %i\n",

					client.addr << 1, ret);

					client->addr << 1, ret);

			continue;

			continue;

		}

		}

		id = ret << 8;

		id = ret << 8;

		reg = 0x1d;

		reg = 0x1d;

		ret = i2c_smbus_read_byte_data(&client, reg);

		ret = i2c_smbus_read_byte_data(client, reg);

		if (ret < 0) {

		if (ret < 0) {

			dev_err(&dev->intf->dev,

			dev_err(&dev->intf->dev,

				"couldn't read from i2c device 0x%02x: error %i\n",

				"couldn't read from i2c device 0x%02x: error %i\n",

				client.addr << 1, ret);

				client->addr << 1, ret);

			continue;

			continue;

		}

		}

		id += ret;

		id += ret;
@@ -245,20 +244,20 @@ static int em28xx_probe_sensor_omnivision(struct em28xx *dev) 
			continue;

			continue;

		/* Read product ID from registers 0x0a-0x0b (BE) */

		/* Read product ID from registers 0x0a-0x0b (BE) */

		reg = 0x0a;

		reg = 0x0a;

		ret = i2c_smbus_read_byte_data(&client, reg);

		ret = i2c_smbus_read_byte_data(client, reg);

		if (ret < 0) {

		if (ret < 0) {

			dev_err(&dev->intf->dev,

			dev_err(&dev->intf->dev,

				"couldn't read from i2c device 0x%02x: error %i\n",

				"couldn't read from i2c device 0x%02x: error %i\n",

				client.addr << 1, ret);

				client->addr << 1, ret);

			continue;

			continue;

		}

		}

		id = ret << 8;

		id = ret << 8;

		reg = 0x0b;

		reg = 0x0b;

		ret = i2c_smbus_read_byte_data(&client, reg);

		ret = i2c_smbus_read_byte_data(client, reg);

		if (ret < 0) {

		if (ret < 0) {

			dev_err(&dev->intf->dev,

			dev_err(&dev->intf->dev,

				"couldn't read from i2c device 0x%02x: error %i\n",

				"couldn't read from i2c device 0x%02x: error %i\n",

				client.addr << 1, ret);

				client->addr << 1, ret);

			continue;

			continue;

		}

		}

		id += ret;

		id += ret;
@@ -309,7 +308,6 @@ static int em28xx_probe_sensor_omnivision(struct em28xx *dev) 
			dev_info(&dev->intf->dev,

			dev_info(&dev->intf->dev,

				 "sensor %s detected\n", name);

				 "sensor %s detected\n", name);





		dev->i2c_client[dev->def_i2c_bus].addr = client.addr;

		return 0;

		return 0;

	}

	}