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Commit aa18cc91 authored by Joshua Scott's avatar Joshua Scott Committed by Guenter Roeck
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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: default avatarJoshua Scott <joshua.scott@alliedtelesis.co.nz>
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent 30fe976f

Documentation/hwmon/adt7470

+17 −0
Original line number Diff line number Diff line
@@ -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

-----

drivers/hwmon/adt7470.c

+74 −0
Original line number Diff line number Diff line
@@ -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,