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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: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Frank Schäfer <fschaefer.oss@googlemail.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
hifive-unleashed-5.1
Frank Schaefer 2017-02-19 15:29:17 -03:00 committed by Mauro Carvalho Chehab
parent 3b8b2e1cea
commit 9e00695364
1 changed files with 20 additions and 22 deletions
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42
drivers/media/usb/em28xx/em28xx-camera.c
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@ -110,44 +110,44 @@ static int em28xx_probe_sensor_micron(struct em28xx *dev)
__be16 id_be;
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;
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 */
/* Read chip ID from register 0x00 */
reg = 0x00;
ret = i2c_master_send(&client, &reg, 1);
ret = i2c_master_send(client, &reg, 1);
if (ret < 0) {
if (ret != -ENXIO)
dev_err(&dev->intf->dev,
"couldn't read from i2c device 0x%02x: error %i\n",
client.addr << 1, ret);
client->addr << 1, ret);
continue;
}
ret = i2c_master_recv(&client, (u8 *)&id_be, 2);
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);
client->addr << 1, ret);
continue;
}
id = be16_to_cpu(id_be);
/* Read chip ID from register 0xff */
reg = 0xff;
ret = i2c_master_send(&client, &reg, 1);
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);
client->addr << 1, ret);
continue;
}
ret = i2c_master_recv(&client, (u8 *)&id_be, 2);
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);
client->addr << 1, ret);
continue;
}
/* 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,
"sensor %s detected\n", name);
dev->i2c_client[dev->def_i2c_bus].addr = client.addr;
return 0;
}
@ -213,30 +212,30 @@ static int em28xx_probe_sensor_omnivision(struct em28xx *dev)
char *name;
u8 reg;
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;
/* NOTE: these devices have the register auto incrementation disabled
* by default, so we have to use single byte reads ! */
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) */
reg = 0x1c;
ret = i2c_smbus_read_byte_data(&client, reg);
ret = i2c_smbus_read_byte_data(client, reg);
if (ret < 0) {
if (ret != -ENXIO)
dev_err(&dev->intf->dev,
"couldn't read from i2c device 0x%02x: error %i\n",
client.addr << 1, ret);
client->addr << 1, ret);
continue;
}
id = ret << 8;
reg = 0x1d;
ret = i2c_smbus_read_byte_data(&client, reg);
ret = i2c_smbus_read_byte_data(client, reg);
if (ret < 0) {
dev_err(&dev->intf->dev,
"couldn't read from i2c device 0x%02x: error %i\n",
client.addr << 1, ret);
client->addr << 1, ret);
continue;
}
id += ret;
@ -245,20 +244,20 @@ static int em28xx_probe_sensor_omnivision(struct em28xx *dev)
continue;
/* Read product ID from registers 0x0a-0x0b (BE) */
reg = 0x0a;
ret = i2c_smbus_read_byte_data(&client, reg);
ret = i2c_smbus_read_byte_data(client, reg);
if (ret < 0) {
dev_err(&dev->intf->dev,
"couldn't read from i2c device 0x%02x: error %i\n",
client.addr << 1, ret);
client->addr << 1, ret);
continue;
}
id = ret << 8;
reg = 0x0b;
ret = i2c_smbus_read_byte_data(&client, reg);
ret = i2c_smbus_read_byte_data(client, reg);
if (ret < 0) {
dev_err(&dev->intf->dev,
"couldn't read from i2c device 0x%02x: error %i\n",
client.addr << 1, ret);
client->addr << 1, ret);
continue;
}
id += ret;
@ -309,7 +308,6 @@ static int em28xx_probe_sensor_omnivision(struct em28xx *dev)
dev_info(&dev->intf->dev,
"sensor %s detected\n", name);
dev->i2c_client[dev->def_i2c_bus].addr = client.addr;
return 0;
}