hwmon: (adt7475) add high frequency support

Systems using 4-wire fans usually require high frequency (22.5kHz)
output on the pwm. Add 22500 as a valid option in the pwmfreq_table. In
high frequency mode the low-order bit are ignored so they can safely be
set to 0.

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/adt7475.c

@@ -852,7 +852,7 @@ static ssize_t set_pwmctrl(struct device *dev, struct device_attribute *attr,
 
 /* List of frequencies for the PWM */
 static const int pwmfreq_table[] = {
-	11, 14, 22, 29, 35, 44, 58, 88
+	11, 14, 22, 29, 35, 44, 58, 88, 22500
 };
 
 static ssize_t show_pwmfreq(struct device *dev, struct device_attribute *attr,
@@ -860,9 +860,10 @@ static ssize_t show_pwmfreq(struct device *dev, struct device_attribute *attr,
 {
 	struct adt7475_data *data = adt7475_update_device(dev);
 	struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);
+	int i = clamp_val(data->range[sattr->index] & 0xf, 0,
+			  ARRAY_SIZE(pwmfreq_table) - 1);
 
-	return sprintf(buf, "%d\n",
-		       pwmfreq_table[data->range[sattr->index] & 7]);
+	return sprintf(buf, "%d\n", pwmfreq_table[i]);
 }
 
 static ssize_t set_pwmfreq(struct device *dev, struct device_attribute *attr,
@@ -883,7 +884,7 @@ static ssize_t set_pwmfreq(struct device *dev, struct device_attribute *attr,
 
 	data->range[sattr->index] =
 		adt7475_read(TEMP_TRANGE_REG(sattr->index));
-	data->range[sattr->index] &= ~7;
+	data->range[sattr->index] &= ~0xf;
 	data->range[sattr->index] |= out;
 
 	i2c_smbus_write_byte_data(client, TEMP_TRANGE_REG(sattr->index),