On Mon, Jan 5, 2015 at 3:09 PM, Joe Perches <joe@xxxxxxxxxxx> wrote: > On Mon, 2015-01-05 at 12:51 +0200, Daniel Baluta wrote: >> On Thu, Jan 1, 2015 at 2:10 AM, Kevin Tsai <ktsai@xxxxxxxxxxxxxxxx> wrote: >> > CM3232 is an advanced ambient light sensor with I2C protocol interface. >> > The I2C slave address is internally hardwired as 0x10 (7-bit). Writing >> > to configure register is byte mode, but reading ALS register requests to >> > use word mode for 16-bit resolution. >> >> This looks good to me. Few comments inline. > [] >> > diff --git a/drivers/iio/light/cm3232.c b/drivers/iio/light/cm3232.c > [] >> > +/** >> > + * cm3232_reg_init() - Initialize CM3232 registers >> > + * @chip: pointer of struct cm3232. >> > + * >> > + * Initialize CM3232 ambient light sensor register to default values. >> > + * >> > + Return: 0 for success; otherwise for error code. >> > + */ >> > +static int cm3232_reg_init(struct cm3232_chip *chip) >> > +{ >> > + struct i2c_client *client = chip->client; >> > + struct cm3232_als_info *als_info; >> > + s32 ret; >> > + >> > + /* Identify device */ >> > + ret = i2c_smbus_read_word_data(client, CM3232_REG_ADDR_ID); >> > + if (ret < 0) >> > + return ret; >> > + if ((ret & 0xFF) != 0x32) >> > + return -ENODEV; >> > + >> > + /* Disable and reset device */ >> > + chip->regs_cmd = CM3232_CMD_ALS_DISABLE | CM3232_CMD_ALS_RESET; >> > + ret = i2c_smbus_write_byte_data(client, CM3232_REG_ADDR_CMD, >> > + chip->regs_cmd); >> > + if (ret < 0) >> > + return ret; >> > + >> > + /* Initialization */ >> > + als_info = chip->als_info = &cm3232_als_info_default; >> > + chip->regs_cmd = CM3232_CMD_DEFAULT; >> > + >> > + /* Configure register */ >> > + ret = i2c_smbus_write_byte_data(client, CM3232_REG_ADDR_CMD, >> > + chip->regs_cmd); >> >> You could directly return i2c_smbus_write_byte_data(..). > > Sometimes it's better to return a specific value > for the error instead of depending on correctness > of all the indirect functions in the call chain. > > In this case, all the smbus_xfer functions must > return 0 on success. Do they? Yes. http://lxr.free-electrons.com/source/drivers/i2c/i2c-core.c#L2845 > > Inspecting the codebase for correctness or not > depending on that correctness is sometimes better > to avoid doing. You have a valid point. Anyhow, AFAIK the code from IIO prefers a direct return. Also, I guess kbuild test robot will complain about it, like here: http://marc.info/?l=linux-kernel&m=141963536230419&w=2 thanks, Daniel. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html