linux-kernel - [PATCH 5.19 156/192] hwmon: (tps23861) fix byte order in resistance register

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Date:   Tue, 13 Sep 2022 16:04:22 +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, Alexandru Gagniuc <mr.nuke.me@...il.com>,
        Guenter Roeck <linux@...ck-us.net>
Subject: [PATCH 5.19 156/192] hwmon: (tps23861) fix byte order in resistance register

From: Alexandru Gagniuc <mr.nuke.me@...il.com>

commit 1f05f65bddd6958d25b133f886da49c1d4bff3fa upstream.

The tps23861 registers are little-endian, and regmap_read_bulk() does
not do byte order conversion. On BE machines, the bytes were swapped,
and the interpretation of the resistance value was incorrect.

To make it work on both big and little-endian machines, use
le16_to_cpu() to convert the resitance register to host byte order.

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@...il.com>
Fixes: fff7b8ab22554 ("hwmon: add Texas Instruments TPS23861 driver")
Cc: stable@...r.kernel.org
Link: https://lore.kernel.org/r/20220905142806.110598-1-mr.nuke.me@gmail.com
Signed-off-by: Guenter Roeck <linux@...ck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/hwmon/tps23861.c |   10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

--- a/drivers/hwmon/tps23861.c
+++ b/drivers/hwmon/tps23861.c
@@ -489,18 +489,20 @@ static char *tps23861_port_poe_plus_stat
 
 static int tps23861_port_resistance(struct tps23861_data *data, int port)
 {
-	u16 regval;
+	unsigned int raw_val;
+	__le16 regval;
 
 	regmap_bulk_read(data->regmap,
 			 PORT_1_RESISTANCE_LSB + PORT_N_RESISTANCE_LSB_OFFSET * (port - 1),
 			 &regval,
 			 2);
 
-	switch (FIELD_GET(PORT_RESISTANCE_RSN_MASK, regval)) {
+	raw_val = le16_to_cpu(regval);
+	switch (FIELD_GET(PORT_RESISTANCE_RSN_MASK, raw_val)) {
 	case PORT_RESISTANCE_RSN_OTHER:
-		return (FIELD_GET(PORT_RESISTANCE_MASK, regval) * RESISTANCE_LSB) / 10000;
+		return (FIELD_GET(PORT_RESISTANCE_MASK, raw_val) * RESISTANCE_LSB) / 10000;
 	case PORT_RESISTANCE_RSN_LOW:
-		return (FIELD_GET(PORT_RESISTANCE_MASK, regval) * RESISTANCE_LSB_LOW) / 10000;
+		return (FIELD_GET(PORT_RESISTANCE_MASK, raw_val) * RESISTANCE_LSB_LOW) / 10000;
 	case PORT_RESISTANCE_RSN_SHORT:
 	case PORT_RESISTANCE_RSN_OPEN:
 	default: