On 7/8/20 4:53 PM, Chu Lin wrote: > Issue: > When binding adm1272 to the adm1275 driver, PEC error is reported. > See blow:
s/blow/below/ Also, unless I am missing something, the error is only seen if PEC is enabled. > adm1275: probe of xxxx failed with error -74 > > Diagnosis: > Per the datasheet of adm1272 and adm1278 (www.analog.com), > PMON_CONFIG (0xd4) is 16bits wide. On the other hand, > PMON_CONFIG (0xd4) for adm1275 is 8bits wide. > The driver should not assume everything is 8bits wide and read only > 8bits from it. > > Solution: > if it is adm1272 or adm1278, use i2c_read_word. Else, use i2c_read_byte > See below for more chips with 16-bit configuration registers. > Signed-off-by: Chu Lin <linchuy...@google.com> > --- > drivers/hwmon/pmbus/adm1275.c | 24 ++++++++++++++++-------- > 1 file changed, 16 insertions(+), 8 deletions(-) > > diff --git a/drivers/hwmon/pmbus/adm1275.c b/drivers/hwmon/pmbus/adm1275.c > index e25f541227da..a0d547d20358 100644 > --- a/drivers/hwmon/pmbus/adm1275.c > +++ b/drivers/hwmon/pmbus/adm1275.c > @@ -472,6 +472,7 @@ static int adm1275_probe(struct i2c_client *client, > struct adm1275_data *data; > const struct i2c_device_id *mid; > const struct coefficients *coefficients; > + s32 (*config_read_fn_ptr)(const struct i2c_client *client, u8 reg); _ptr is really not needed here and redundant. A variable pointing to a function is always a pointer. > int vindex = -1, voindex = -1, cindex = -1, pindex = -1; > int tindex = -1; > u32 shunt; > @@ -510,14 +511,6 @@ static int adm1275_probe(struct i2c_client *client, > "Device mismatch: Configured %s, detected %s\n", > id->name, mid->name); > > - config = i2c_smbus_read_byte_data(client, ADM1275_PMON_CONFIG); > - if (config < 0) > - return config; > - > - device_config = i2c_smbus_read_byte_data(client, ADM1275_DEVICE_CONFIG); > - if (device_config < 0) > - return device_config; > - The reason for doing this here was to avoid the memory allocation failure on error. I don't really see the point of moving the code block. > data = devm_kzalloc(&client->dev, sizeof(struct adm1275_data), > GFP_KERNEL); > if (!data) > @@ -532,6 +525,21 @@ static int adm1275_probe(struct i2c_client *client, > > data->id = mid->driver_data; > > + /* adm1272 and adm1278 supports temperature monitoring. The config and > device config > + * are 16bits wide for these two devices. On the other hand, other > devices are 8 bits wide > + */ Standard multi-line comments, please. Also, the destinction is really based on have_power_sampling, though that is set only later. > + if (data->id == adm1272 || data->id == adm1278) > + config_read_fn_ptr = &i2c_smbus_read_word_data; Function pointers don't need &. For ADM1293 and ADM1294, the registers are also 16 bit wide (again, see use of have_power_sampling). Thanks, Guenter > + else > + config_read_fn_ptr = &i2c_smbus_read_byte_data; > + config = config_read_fn_ptr(client, ADM1275_PMON_CONFIG); > + if (config < 0) > + return config; > + > + device_config = config_read_fn_ptr(client, ADM1275_DEVICE_CONFIG); > + if (device_config < 0) > + return device_config; > + > info = &data->info; > > info->pages = 1; >
