From a60f58eb70e4e4c2ba4ace8b292dea64e5b7b290 Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Mon, 27 Jul 2026 13:13:54 -0700 Subject: hwmon: (lm63) Mask PWM frequency multiplier to supported bits Sashiko is concerned that reading a PWM frequency multiplier outside the supported range of [1, 31] might result in bad PWM values written to the chip. Technically, the chip should never return a value with the upper 3 bits set, so this should never happen. However, it is unknown if there are LM63 variants where the upper bits of the register can be written. Mask the register value read from the chip to only accept the lower 5 bit when reading it from the chip to avoid the problem. Reported-by: Sashiko Signed-off-by: Guenter Roeck --- drivers/hwmon/lm63.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/hwmon/lm63.c b/drivers/hwmon/lm63.c index e2a429e579ac..da09770c05e7 100644 --- a/drivers/hwmon/lm63.c +++ b/drivers/hwmon/lm63.c @@ -247,8 +247,7 @@ static struct lm63_data *lm63_update_device(struct device *dev) LM63_REG_TACH_LIMIT_MSB) << 8); } - data->pwm1_freq = i2c_smbus_read_byte_data(client, - LM63_REG_PWM_FREQ); + data->pwm1_freq = i2c_smbus_read_byte_data(client, LM63_REG_PWM_FREQ) & 0x1f; if (data->pwm1_freq == 0) data->pwm1_freq = 1; data->pwm1[0] = i2c_smbus_read_byte_data(client, @@ -1187,7 +1186,7 @@ static void lm63_init_client(struct lm63_data *data) data->config |= 0x04; /* We may need pwm1_freq before ever updating the client data */ - data->pwm1_freq = i2c_smbus_read_byte_data(client, LM63_REG_PWM_FREQ); + data->pwm1_freq = i2c_smbus_read_byte_data(client, LM63_REG_PWM_FREQ) & 0x1f; if (data->pwm1_freq == 0) data->pwm1_freq = 1; -- cgit v1.2.3