From: Guenter Roeck Date: Mon, 27 Jul 2026 20:13:54 +0000 (-0700) Subject: hwmon: (lm63) Mask PWM frequency multiplier to supported bits X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a60f58eb70e4e4c2ba4ace8b292dea64e5b7b290;p=thirdparty%2Flinux.git 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 --- 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;