From aa18cc911ae2f172429d59169e95726b8e63525c Mon Sep 17 00:00:00 2001 From: Joshua Scott Date: Mon, 8 Aug 2016 13:35:45 +1200 Subject: [PATCH] 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 Signed-off-by: Guenter Roeck --- Documentation/hwmon/adt7470 | 17 +++++++++ drivers/hwmon/adt7470.c | 74 +++++++++++++++++++++++++++++++++++++ 2 files changed, 91 insertions(+) diff --git a/Documentation/hwmon/adt7470 b/Documentation/hwmon/adt7470 index 8ce4aa0a0f55..fe68e18a0c8d 100644 --- a/Documentation/hwmon/adt7470 +++ b/Documentation/hwmon/adt7470 @@ -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 ----- diff --git a/drivers/hwmon/adt7470.c b/drivers/hwmon/adt7470.c index f5da39a68929..94550d79ca48 100644 --- a/drivers/hwmon/adt7470.c +++ b/drivers/hwmon/adt7470.c @@ -32,6 +32,7 @@ #include #include #include +#include /* 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, -- 2.20.1