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hwmon: (adt7470) Expose PWM frequency to sysfs 

The ADT7470 supports a variety of PWM frequencies. This patch allows the
frequency to be configured and viewed through the sysfs entry pwm1_freq.

Signed-off-by: Joshua Scott <joshua.scott@alliedtelesis.co.nz>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Joshua Scott 2016-08-08 13:35:45 +12:00 committed by Guenter Roeck
parent 30fe976fe7
commit aa18cc911a
2 changed files with 91 additions and 0 deletions
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17
Documentation/hwmon/adt7470
View File

@ -65,6 +65,23 @@ from 0 (off) to 255 (full speed). Fan speed will be set to maximum when the
temperature sensor associated with the PWM control exceeds
pwm#_auto_point2_temp.
The driver also allows control of the PWM frequency:
* pwm1_freq
The PWM frequency is rounded to the nearest one of:
* 11.0 Hz
* 14.7 Hz
* 22.1 Hz
* 29.4 Hz
* 35.3 Hz
* 44.1 Hz
* 58.8 Hz
* 88.2 Hz
* 1.4 kHz
* 22.5 kHz
Notes
-----

74
drivers/hwmon/adt7470.c
View File

@ -32,6 +32,7 @@
#include <linux/log2.h>
#include <linux/kthread.h>
#include <linux/slab.h>
#include <linux/util_macros.h>
/* Addresses to scan */
static const unsigned short normal_i2c[] = { 0x2C, 0x2E, 0x2F, I2C_CLIENT_END };
@ -83,6 +84,7 @@ static const unsigned short normal_i2c[] = { 0x2C, 0x2E, 0x2F, I2C_CLIENT_END };
#define ADT7470_REG_PWM_MIN_MAX_ADDR 0x6D
#define ADT7470_REG_PWM_TEMP_MIN_BASE_ADDR 0x6E
#define ADT7470_REG_PWM_TEMP_MIN_MAX_ADDR 0x71
#define ADT7470_REG_CFG_2 0x74
#define ADT7470_REG_ACOUSTICS12 0x75
#define ADT7470_REG_ACOUSTICS34 0x76
#define ADT7470_REG_DEVICE 0x3D
@ -142,6 +144,11 @@ static const unsigned short normal_i2c[] = { 0x2C, 0x2E, 0x2F, I2C_CLIENT_END };
#define FAN_PERIOD_INVALID 65535
#define FAN_DATA_VALID(x) ((x) && (x) != FAN_PERIOD_INVALID)
/* Config registers 1 and 2 include fields for selecting the PWM frequency */
#define ADT7470_CFG_LF 0x40
#define ADT7470_FREQ_MASK 0x70
#define ADT7470_FREQ_SHIFT 4
struct adt7470_data {
struct i2c_client *client;
struct mutex lock;
@ -688,6 +695,70 @@ static ssize_t set_pwm(struct device *dev, struct device_attribute *devattr,
return count;
}
/* These are the valid PWM frequencies to the nearest Hz */
static const int adt7470_freq_map[] = {
11, 15, 22, 29, 35, 44, 59, 88, 1400, 22500
};
static ssize_t show_pwm_freq(struct device *dev,
struct device_attribute *devattr, char *buf)
{
struct adt7470_data *data = adt7470_update_device(dev);
unsigned char cfg_reg_1;
unsigned char cfg_reg_2;
int index;
mutex_lock(&data->lock);
cfg_reg_1 = i2c_smbus_read_byte_data(data->client, ADT7470_REG_CFG);
cfg_reg_2 = i2c_smbus_read_byte_data(data->client, ADT7470_REG_CFG_2);
mutex_unlock(&data->lock);
index = (cfg_reg_2 & ADT7470_FREQ_MASK) >> ADT7470_FREQ_SHIFT;
if (!(cfg_reg_1 & ADT7470_CFG_LF))
index += 8;
if (index >= ARRAY_SIZE(adt7470_freq_map))
index = ARRAY_SIZE(adt7470_freq_map) - 1;
return scnprintf(buf, PAGE_SIZE, "%d\n", adt7470_freq_map[index]);
}
static ssize_t set_pwm_freq(struct device *dev,
struct device_attribute *devattr,
const char *buf, size_t count)
{
struct adt7470_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
long freq;
int index;
int low_freq = ADT7470_CFG_LF;
unsigned char val;
if (kstrtol(buf, 10, &freq))
return -EINVAL;
/* Round the user value given to the closest available frequency */
index = find_closest(freq, adt7470_freq_map,
ARRAY_SIZE(adt7470_freq_map));
if (index >= 8) {
index -= 8;
low_freq = 0;
}
mutex_lock(&data->lock);
/* Configuration Register 1 */
val = i2c_smbus_read_byte_data(client, ADT7470_REG_CFG);
i2c_smbus_write_byte_data(client, ADT7470_REG_CFG,
(val & ~ADT7470_CFG_LF) | low_freq);
/* Configuration Register 2 */
val = i2c_smbus_read_byte_data(client, ADT7470_REG_CFG_2);
i2c_smbus_write_byte_data(client, ADT7470_REG_CFG_2,
(val & ~ADT7470_FREQ_MASK) | (index << ADT7470_FREQ_SHIFT));
mutex_unlock(&data->lock);
return count;
}
static ssize_t show_pwm_max(struct device *dev,
struct device_attribute *devattr,
char *buf)
@ -1038,6 +1109,8 @@ static SENSOR_DEVICE_ATTR(pwm2, S_IWUSR | S_IRUGO, show_pwm, set_pwm, 1);
static SENSOR_DEVICE_ATTR(pwm3, S_IWUSR | S_IRUGO, show_pwm, set_pwm, 2);
static SENSOR_DEVICE_ATTR(pwm4, S_IWUSR | S_IRUGO, show_pwm, set_pwm, 3);
static DEVICE_ATTR(pwm1_freq, S_IWUSR | S_IRUGO, show_pwm_freq, set_pwm_freq);
static SENSOR_DEVICE_ATTR(pwm1_auto_point1_pwm, S_IWUSR | S_IRUGO,
show_pwm_min, set_pwm_min, 0);
static SENSOR_DEVICE_ATTR(pwm2_auto_point1_pwm, S_IWUSR | S_IRUGO,
@ -1154,6 +1227,7 @@ static struct attribute *adt7470_attrs[] = {
&sensor_dev_attr_fan4_alarm.dev_attr.attr,
&sensor_dev_attr_force_pwm_max.dev_attr.attr,
&sensor_dev_attr_pwm1.dev_attr.attr,
&dev_attr_pwm1_freq.attr,
&sensor_dev_attr_pwm2.dev_attr.attr,
&sensor_dev_attr_pwm3.dev_attr.attr,
&sensor_dev_attr_pwm4.dev_attr.attr,