From: Michael Lawnick <[email protected]> After system startup currently there is no way to add an i2c client to subsystem. This may occur if the client sits on a subsystem that was powerless at the beginning or is plugged in at runtime. This patch adds ioctl to /dev/i2c-X to initiate a probe of an client and to remove a client that may have gone. Example: fd=open("/dev/i2c-1",O_RDWR); ioctl(fd,I2C_PROBE,"lm75,0x49"); close(fd); will start probing of an lm75 compatible sensor at bus 1, id 0x49 ioctl(fd,I2C_REMOVE,0x49) removes it again.
Signed-off-by: Michael Lawnick <[email protected]> --- Add ioctls I2C_PROBE and I2C_REMOVE to /dev/i2c-x drivers/i2c/i2c-dev.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++- include/linux/i2c-dev.h | 2 + 2 files changed, 51 insertions(+), 1 deletions(-) diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c index c171988..82cbe7f --- a/drivers/i2c/i2c-dev.c +++ b/drivers/i2c/i2c-dev.c @@ -367,9 +367,22 @@ static noinline int i2cdev_ioctl_smbus(struct i2c_client *client, return res; } +static int i2c_check_addr(struct device *dev, void *addrp) +{ + struct i2c_client *client = i2c_verify_client(dev); + int addr = *(int *)addrp; + + if (client && client->addr == addr) + return -EBUSY; + return 0; +} + static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { - struct i2c_client *client = (struct i2c_client *)file->private_data; + struct i2c_client *bus_client, *client = (struct i2c_client *)file->private_data; + struct i2c_board_info bInfo; + struct device *dev; + char *colon, request[I2C_NAME_SIZE + 5]; unsigned long funcs; dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n", @@ -424,6 +437,41 @@ static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) case I2C_TIMEOUT: client->adapter->timeout = arg; break; + case I2C_PROBE: + memset(&bInfo, 0, sizeof(bInfo)); + copy_from_user(request, (char *)arg, sizeof(request)); + + colon = strchr(request, ','); + if((!colon) || (colon - request > I2C_NAME_SIZE - 1)) + return -EINVAL; + + strncpy(bInfo.type, request, colon - request); + bInfo.type[I2C_NAME_SIZE - 1] = '\0'; + bInfo.addr = simple_strtoul(colon + 1, NULL, 0); + + bus_client = i2c_new_device(client->adapter, &bInfo); + + if(!bus_client) + return -EIO; + + if(!bus_client->driver) + { + /* probe failed -> cleanup */ + i2c_unregister_device(bus_client); + return -ENODEV; + } + break; + case I2C_REMOVE: + dev = device_find_child(&client->adapter->dev, &arg, i2c_check_addr); + if (!dev) + return -ENODEV; + + bus_client = i2c_verify_client(dev); + if(!bus_client) + return -EIO; + + i2c_unregister_device(bus_client); + break; default: /* NOTE: returning a fault code here could cause trouble * in buggy userspace code. Some old kernel bugs returned diff --git a/include/linux/i2c-dev.h b/include/linux/i2c-dev.h index 311315b..8b66638 --- a/include/linux/i2c-dev.h +++ b/include/linux/i2c-dev.h @@ -50,6 +50,8 @@ #define I2C_PEC 0x0708 /* != 0 to use PEC with SMBus */ #define I2C_SMBUS 0x0720 /* SMBus transfer */ +#define I2C_PROBE 0x0730 /* Probe for client "<name>,<addr>" */ +#define I2C_REMOVE 0x0731 /* Remove client <addr> */ /* This is the structure as used in the I2C_SMBUS ioctl call */ struct i2c_smbus_ioctl_data { -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
