diff options
Diffstat (limited to 'drivers/hwmon/it87.c')
| -rw-r--r-- | drivers/hwmon/it87.c | 34 |
1 files changed, 25 insertions, 9 deletions
diff --git a/drivers/hwmon/it87.c b/drivers/hwmon/it87.c index 81a43db371f7..5f6c3ad4f3dd 100644 --- a/drivers/hwmon/it87.c +++ b/drivers/hwmon/it87.c @@ -502,15 +502,25 @@ static int DIV_TO_REG(int val) } #define DIV_FROM_REG(val) (1 << (val)) +/* + * PWM base frequencies. The frequency has to be divided by either 128 or 256, + * depending on the chip type, to calculate the actual PWM frequency. + * + * Some of the chip datasheets suggest a base frequency of 51 kHz instead + * of 750 kHz for the slowest base frequency, resulting in a PWM frequency + * of 200 Hz. Sometimes both PWM frequency select registers are affected, + * sometimes just one. It is unknown if this is a datasheet error or real, + * so this is ignored for now. + */ static const unsigned int pwm_freq[8] = { - 48000000 / 128, - 24000000 / 128, - 12000000 / 128, - 8000000 / 128, - 6000000 / 128, - 3000000 / 128, - 1500000 / 128, - 750000 / 128, + 48000000, + 24000000, + 12000000, + 8000000, + 6000000, + 3000000, + 1500000, + 750000, }; static int it87_probe(struct platform_device *pdev); @@ -828,8 +838,11 @@ static ssize_t show_pwm_freq(struct device *dev, struct device_attribute *attr, { struct it87_data *data = it87_update_device(dev); int index = (data->fan_ctl >> 4) & 0x07; + unsigned int freq; - return sprintf(buf, "%u\n", pwm_freq[index]); + freq = pwm_freq[index] / (has_newer_autopwm(data) ? 256 : 128); + + return sprintf(buf, "%u\n", freq); } static ssize_t set_fan(struct device *dev, struct device_attribute *attr, @@ -1051,6 +1064,9 @@ static ssize_t set_pwm_freq(struct device *dev, if (kstrtoul(buf, 10, &val) < 0) return -EINVAL; + val = clamp_val(val, 0, 1000000); + val *= has_newer_autopwm(data) ? 256 : 128; + /* Search for the nearest available frequency */ for (i = 0; i < 7; i++) { if (val > (pwm_freq[i] + pwm_freq[i+1]) / 2) |