hwmon: (pmbus/bpa-rs600) Don't use rated limits as warn limits

In the initial implementation a number of PMBUS_x_WARN_LIMITs were
mapped to MFR fields. This was incorrect as these MFR limits reflect the
rated limit as opposed to a limit which will generate warning. Instead
return -ENXIO like we were already doing for other WARN_LIMITs.

Subsequently these rated limits have been exposed generically as new
fields in the sysfs ABI so the values are still available.

Fixes: 15b2703e ("hwmon: (pmbus) Add driver for BluTek BPA-RS600")
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Link: https://lore.kernel.org/r/20210812014000.26293-2-chris.packham@alliedtelesis.co.nzSigned-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/pmbus/bpa-rs600.c

@@ -12,15 +12,6 @@
 #include <linux/pmbus.h>
 #include "pmbus.h"
 
-#define BPARS600_MFR_VIN_MIN	0xa0
-#define BPARS600_MFR_VIN_MAX	0xa1
-#define BPARS600_MFR_IIN_MAX	0xa2
-#define BPARS600_MFR_PIN_MAX	0xa3
-#define BPARS600_MFR_VOUT_MIN	0xa4
-#define BPARS600_MFR_VOUT_MAX	0xa5
-#define BPARS600_MFR_IOUT_MAX	0xa6
-#define BPARS600_MFR_POUT_MAX	0xa7
-
 enum chips { bpa_rs600, bpd_rs600 };
 
 static int bpa_rs600_read_byte_data(struct i2c_client *client, int page, int reg)
@@ -83,29 +74,13 @@ static int bpa_rs600_read_word_data(struct i2c_client *client, int page, int pha
 
 	switch (reg) {
 	case PMBUS_VIN_UV_WARN_LIMIT:
-		ret = pmbus_read_word_data(client, 0, 0xff, BPARS600_MFR_VIN_MIN);
-		break;
 	case PMBUS_VIN_OV_WARN_LIMIT:
-		ret = pmbus_read_word_data(client, 0, 0xff, BPARS600_MFR_VIN_MAX);
-		break;
 	case PMBUS_VOUT_UV_WARN_LIMIT:
-		ret = pmbus_read_word_data(client, 0, 0xff, BPARS600_MFR_VOUT_MIN);
-		break;
 	case PMBUS_VOUT_OV_WARN_LIMIT:
-		ret = pmbus_read_word_data(client, 0, 0xff, BPARS600_MFR_VOUT_MAX);
-		break;
 	case PMBUS_IIN_OC_WARN_LIMIT:
-		ret = pmbus_read_word_data(client, 0, 0xff, BPARS600_MFR_IIN_MAX);
-		break;
 	case PMBUS_IOUT_OC_WARN_LIMIT:
-		ret = pmbus_read_word_data(client, 0, 0xff, BPARS600_MFR_IOUT_MAX);
-		break;
 	case PMBUS_PIN_OP_WARN_LIMIT:
-		ret = pmbus_read_word_data(client, 0, 0xff, BPARS600_MFR_PIN_MAX);
-		break;
 	case PMBUS_POUT_OP_WARN_LIMIT:
-		ret = pmbus_read_word_data(client, 0, 0xff, BPARS600_MFR_POUT_MAX);
-		break;
 	case PMBUS_VIN_UV_FAULT_LIMIT:
 	case PMBUS_VIN_OV_FAULT_LIMIT:
 	case PMBUS_VOUT_UV_FAULT_LIMIT: