From c88a6338ae485e4d6210cc74cdb7664d6476c925 Mon Sep 17 00:00:00 2001 From: Ali Ahmet Memis Date: Mon, 3 Aug 2026 10:21:48 +0000 Subject: [PATCH] hwmon: (nct6694) do not expose enable on DTIN temperature channels The driver registers 26 temperature channels, all advertising HWMON_T_ENABLE, and indexes the enable bitmap with the raw channel: data->hwmon_en.tin_en[channel / 8] |= BIT(channel % 8); tin_en is two bytes and only covers the 5 THR and 5 TDP channels (index 0-9). The 16 DTIN channels (index 10-25) are enabled by the firmware and were never meant to carry an enable bit. Because the control structure is packed, writing temp17_enable and above indexes past tin_en into the fin_en bytes that follow it, so it toggles fan enable state instead; nct6694_hwmon_init() then sends the whole structure back to the device, and reads report fan state as temperature state. It stays within the structure, so this is not a memory safety problem, but on a board that uses the fan channels it is not harmless. Give the DTIN channels a temperature config without HWMON_T_ENABLE so the core never creates their enable attribute. The enable path is then reachable only for the first 10 channels, which stay within tin_en, and fin_en is left alone. The DTIN input and limit attributes are unchanged. Fixes: 197e779d29d8 ("hwmon: Add Nuvoton NCT6694 HWMON support") Suggested-by: Ming Yu Link: https://lore.kernel.org/all/20260802124730.20387-1-ali@iusegentoo.com/ Signed-off-by: Ali Ahmet Memis Link: https://patch.msgid.link/20260803102148.14196-1-ali@iusegentoo.com Signed-off-by: Guenter Roeck --- drivers/hwmon/nct6694-hwmon.c | 35 +++++++++++++++++++---------------- 1 file changed, 19 insertions(+), 16 deletions(-) diff --git a/drivers/hwmon/nct6694-hwmon.c b/drivers/hwmon/nct6694-hwmon.c index 6dcf22ca5018..9a9a4db434c4 100644 --- a/drivers/hwmon/nct6694-hwmon.c +++ b/drivers/hwmon/nct6694-hwmon.c @@ -159,6 +159,9 @@ static inline s8 temp_to_reg(long val) #define NCT6694_HWMON_TEMP_CONFIG (HWMON_T_INPUT | HWMON_T_ENABLE | \ HWMON_T_MAX | HWMON_T_MAX_HYST | \ HWMON_T_MAX_ALARM) +#define NCT6694_HWMON_DTIN_CONFIG (HWMON_T_INPUT | \ + HWMON_T_MAX | HWMON_T_MAX_HYST | \ + HWMON_T_MAX_ALARM) #define NCT6694_HWMON_FAN_CONFIG (HWMON_F_INPUT | HWMON_F_ENABLE | \ HWMON_F_MIN | HWMON_F_MIN_ALARM) #define NCT6694_HWMON_PWM_CONFIG (HWMON_PWM_INPUT | HWMON_PWM_ENABLE | \ @@ -193,22 +196,22 @@ static const struct hwmon_channel_info *nct6694_info[] = { NCT6694_HWMON_TEMP_CONFIG, /* TDP2 */ NCT6694_HWMON_TEMP_CONFIG, /* TDP3 */ NCT6694_HWMON_TEMP_CONFIG, /* TDP4 */ - NCT6694_HWMON_TEMP_CONFIG, /* DTIN0 */ - NCT6694_HWMON_TEMP_CONFIG, /* DTIN1 */ - NCT6694_HWMON_TEMP_CONFIG, /* DTIN2 */ - NCT6694_HWMON_TEMP_CONFIG, /* DTIN3 */ - NCT6694_HWMON_TEMP_CONFIG, /* DTIN4 */ - NCT6694_HWMON_TEMP_CONFIG, /* DTIN5 */ - NCT6694_HWMON_TEMP_CONFIG, /* DTIN6 */ - NCT6694_HWMON_TEMP_CONFIG, /* DTIN7 */ - NCT6694_HWMON_TEMP_CONFIG, /* DTIN8 */ - NCT6694_HWMON_TEMP_CONFIG, /* DTIN9 */ - NCT6694_HWMON_TEMP_CONFIG, /* DTIN10 */ - NCT6694_HWMON_TEMP_CONFIG, /* DTIN11 */ - NCT6694_HWMON_TEMP_CONFIG, /* DTIN12 */ - NCT6694_HWMON_TEMP_CONFIG, /* DTIN13 */ - NCT6694_HWMON_TEMP_CONFIG, /* DTIN14 */ - NCT6694_HWMON_TEMP_CONFIG), /* DTIN15 */ + NCT6694_HWMON_DTIN_CONFIG, /* DTIN0 */ + NCT6694_HWMON_DTIN_CONFIG, /* DTIN1 */ + NCT6694_HWMON_DTIN_CONFIG, /* DTIN2 */ + NCT6694_HWMON_DTIN_CONFIG, /* DTIN3 */ + NCT6694_HWMON_DTIN_CONFIG, /* DTIN4 */ + NCT6694_HWMON_DTIN_CONFIG, /* DTIN5 */ + NCT6694_HWMON_DTIN_CONFIG, /* DTIN6 */ + NCT6694_HWMON_DTIN_CONFIG, /* DTIN7 */ + NCT6694_HWMON_DTIN_CONFIG, /* DTIN8 */ + NCT6694_HWMON_DTIN_CONFIG, /* DTIN9 */ + NCT6694_HWMON_DTIN_CONFIG, /* DTIN10 */ + NCT6694_HWMON_DTIN_CONFIG, /* DTIN11 */ + NCT6694_HWMON_DTIN_CONFIG, /* DTIN12 */ + NCT6694_HWMON_DTIN_CONFIG, /* DTIN13 */ + NCT6694_HWMON_DTIN_CONFIG, /* DTIN14 */ + NCT6694_HWMON_DTIN_CONFIG), /* DTIN15 */ HWMON_CHANNEL_INFO(fan, NCT6694_HWMON_FAN_CONFIG, /* FIN0 */