From c0d04e9112ad59d73f23f3b0f6726c5e798dfcbf Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Sun, 4 Dec 2016 18:15:25 -0800 Subject: hwmon: (nct7802) Fix overflows seen when writing into limit attributes Fix overflows seen when writing voltage and temperature limit attributes. The value passed to DIV_ROUND_CLOSEST() needs to be clamped, and the value parameter passed to nct7802_write_fan_min() is an unsigned long. Also, writing values larger than 2700000 into a fan limit attribute results in writing 0 into the chip's limit registers. The exact behavior when writing this value is unspecified. For consistency, report a limit of 1350000 if the chip register reads 0. This may be wrong, and the chip behavior should be verified with the actual chip, but it is better than reporting a value of 0 (which, when written, results in writing a value of 0x1fff into the chip register). Fixes: 3434f3783580 ("hwmon: Driver for Nuvoton NCT7802Y") Reviewed-by: Jean Delvare Signed-off-by: Guenter Roeck --- drivers/hwmon/nct7802.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/hwmon/nct7802.c b/drivers/hwmon/nct7802.c index 3ce33d244cc0..12b94b094c0d 100644 --- a/drivers/hwmon/nct7802.c +++ b/drivers/hwmon/nct7802.c @@ -259,13 +259,15 @@ static int nct7802_read_fan_min(struct nct7802_data *data, u8 reg_fan_low, ret = 0; else if (ret) ret = DIV_ROUND_CLOSEST(1350000U, ret); + else + ret = 1350000U; abort: mutex_unlock(&data->access_lock); return ret; } static int nct7802_write_fan_min(struct nct7802_data *data, u8 reg_fan_low, - u8 reg_fan_high, unsigned int limit) + u8 reg_fan_high, unsigned long limit) { int err; @@ -326,8 +328,8 @@ static int nct7802_write_voltage(struct nct7802_data *data, int nr, int index, int shift = 8 - REG_VOLTAGE_LIMIT_MSB_SHIFT[index - 1][nr]; int err; + voltage = clamp_val(voltage, 0, 0x3ff * nct7802_vmul[nr]); voltage = DIV_ROUND_CLOSEST(voltage, nct7802_vmul[nr]); - voltage = clamp_val(voltage, 0, 0x3ff); mutex_lock(&data->access_lock); err = regmap_write(data->regmap, @@ -402,7 +404,7 @@ static ssize_t store_temp(struct device *dev, struct device_attribute *attr, if (err < 0) return err; - val = clamp_val(DIV_ROUND_CLOSEST(val, 1000), -128, 127); + val = DIV_ROUND_CLOSEST(clamp_val(val, -128000, 127000), 1000); err = regmap_write(data->regmap, nr, val & 0xff); return err ? : count; -- cgit v1.2.3