[hwmon PATCH v2 5/8] hwmon: (adt7470) Fix temperature alarm logic in hwmon_temp_read()

During the conversion the alarm callback started interpreting the
channel index as an alarm bitmask, resulting in incorrect alarm
reporting. Compute the proper alarm bit instead.

Reported-by: [email protected]
Closes: https://lore.kernel.org/r/[email protected]
Fixes: fc958a61ff6d ("hwmon: (adt7470) Convert to devm_hwmon_device_register_with_info API")
Signed-off-by: Luiz Angelo Daros de Luca <[email protected]>
---
 drivers/hwmon/adt7470.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/adt7470.c b/drivers/hwmon/adt7470.c
index a34635526aaa..c6fc7d38d698 100644
--- a/drivers/hwmon/adt7470.c
+++ b/drivers/hwmon/adt7470.c
@@ -110,6 +110,21 @@ static const unsigned short normal_i2c[] = { 0x2C, 0x2E, 0x2F, I2C_CLIENT_END };
 
 #define ALARM2(x)		((x) << 8)
 
+/* TEMP1..TEMP7 (ch 0..6) are, respectively BIT(0)..BIT(6) of reg 0x41 and
+ * 0x72, or BIT(0)..BIT(6) of data->alarm.
+ * TEMP8..TEMP9 (ch 7..9) are, respectively BIT(0)..BIT(2) of reg 0x42 and
+ * 0x73, or BIT(8)..BIT(10) of data->alarm.
+ */
+#define TEMP_ALARM_BIT(ch)	({		\
+	typeof(ch) _ch = (ch);			\
+	(1 << (_ch < 7 ? _ch : _ch + 1));	\
+})
+
+/* FAN1..FAN4 (ch 0..3) are respectively BIT(4)..BIT(7) in
+ * reg 0x42 and 0x73 or BIT(12)..BIT(15) in data->alarm.
+ */
+#define FAN_ALARM_BIT(ch)	(1 << (12 + (ch)))
+
 #define ADT7470_VENDOR		0x41
 #define ADT7470_DEVICE		0x70
 /* datasheet only mentions a revision 2 */
@@ -569,7 +584,7 @@ static int adt7470_temp_read(struct device *dev, u32 attr, int channel, long *va
 		*val = 1000 * data->temp_max[channel];
 		break;
 	case hwmon_temp_alarm:
-		*val = !!(data->alarm & channel);
+		*val = !!(data->alarm & TEMP_ALARM_BIT(channel));
 		break;
 	default:
 		return -EOPNOTSUPP;
@@ -668,7 +683,7 @@ static int adt7470_fan_read(struct device *dev, u32 attr, int channel, long *val
 			*val = 0;
 		break;
 	case hwmon_fan_alarm:
-		*val = !!(data->alarm & (1 << (12 + channel)));
+		*val = !!(data->alarm & FAN_ALARM_BIT(channel));
 		break;
 	default:
 		return -EOPNOTSUPP;

-- 
2.55.0