hwmon: (pmbus/ibm-cffps) max_power_out swap changes

The bytes for max_power_out from the ibm-cffps devices differ in byte
order for some power supplies.

The Witherspoon power supply returns the bytes in MSB/LSB order.

The Rainier power supply returns the bytes in LSB/MSB order.

The Witherspoon power supply uses version cffps1. The Rainier power
supply should use version cffps2. If version is cffps1, swap the bytes
before output to max_power_out.

Tested:
    Witherspoon before: 3148. Witherspoon after: 3148.
    Rainier before: 53255. Rainier after: 2000.

Signed-off-by: Brandon Wyman <bjwyman@gmail.com>
Reviewed-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20210928205051.1222815-1-bjwyman@gmail.com
[groeck: Replaced yoda programming]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/drivers/hwmon/pmbus/ibm-cffps.c b/drivers/hwmon/pmbus/ibm-cffps.c
index df712ce..53f7d14 100644 (file)
--- a/drivers/hwmon/pmbus/ibm-cffps.c
+++ b/drivers/hwmon/pmbus/ibm-cffps.c
@@ -171,8 +171,14 @@ static ssize_t ibm_cffps_debugfs_read(struct file *file, char __user *buf,
                cmd = CFFPS_SN_CMD;
                break;
        case CFFPS_DEBUGFS_MAX_POWER_OUT:
-               rc = i2c_smbus_read_word_swapped(psu->client,
-                                                CFFPS_MAX_POWER_OUT_CMD);
+               if (psu->version == cffps1) {
+                       rc = i2c_smbus_read_word_swapped(psu->client,
+                                       CFFPS_MAX_POWER_OUT_CMD);
+               } else {
+                       rc = i2c_smbus_read_word_data(psu->client,
+                                       CFFPS_MAX_POWER_OUT_CMD);
+               }
+
                if (rc < 0)
                        return rc;