linux-kernel - [PATCH 5.10 22/22] hwmon: (pmbus/ibm-cffps) max_power

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Date:   Thu, 14 Oct 2021 16:54:28 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Brandon Wyman <bjwyman@...il.com>,
        Eddie James <eajames@...ux.ibm.com>,
        Guenter Roeck <linux@...ck-us.net>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.10 22/22] hwmon: (pmbus/ibm-cffps) max_power_out swap changes

From: Brandon Wyman <bjwyman@...il.com>

[ Upstream commit f067d5585cda2de1e47dde914a8a4f151659e0ad ]

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@...il.com>
Reviewed-by: Eddie James <eajames@...ux.ibm.com>
Link: https://lore.kernel.org/r/20210928205051.1222815-1-bjwyman@gmail.com
[groeck: Replaced yoda programming]
Signed-off-by: Guenter Roeck <linux@...ck-us.net>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/hwmon/pmbus/ibm-cffps.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/pmbus/ibm-cffps.c b/drivers/hwmon/pmbus/ibm-cffps.c
index 79bc2032dcb2..da261d32450d 100644
--- 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;
 
-- 
2.33.0