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hwmon: (max6650) Allow fan shutdown and initial rpm target

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The fan can be stopped by writing "3" to pwm1_enable in sysfs.

Add devicetree property for early initialization of the fan controller
to prevent overheating, for example when resetting the board while the
fan was completely turned off.

Also improve error reporting, I2C failures were ignored while writing
new values.

Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Mike Looijmans 2016-08-24 10:13:26 +02:00 committed by Guenter Roeck
parent a6cdeefeca
commit 20005cc58d
2 changed files with 68 additions and 41 deletions
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1
Documentation/hwmon/max6650
View File

@ -34,6 +34,7 @@ fan3_input ro "
fan4_input ro "
fan1_target rw desired fan speed in RPM (closed loop mode only)
pwm1_enable rw regulator mode, 0=full on, 1=open loop, 2=closed loop
3=off
pwm1 rw relative speed (0-255), 255=max. speed.
Used in open loop mode only.
fan1_div rw sets the speed range the inputs can handle. Legal

108
drivers/hwmon/max6650.c
View File

@ -185,6 +185,30 @@ static struct max6650_data *max6650_update_device(struct device *dev)
return data;
}
/*
* Change the operating mode of the chip (if needed).
* mode is one of the MAX6650_CFG_MODE_* values.
*/
static int max6650_set_operating_mode(struct max6650_data *data, u8 mode)
{
int result;
u8 config = data->config;
if (mode == (config & MAX6650_CFG_MODE_MASK))
return 0;
config = (config & ~MAX6650_CFG_MODE_MASK) | mode;
result = i2c_smbus_write_byte_data(data->client, MAX6650_REG_CONFIG,
config);
if (result < 0)
return result;
data->config = config;
return 0;
}
static ssize_t get_fan(struct device *dev, struct device_attribute *devattr,
char *buf)
{
@ -266,18 +290,12 @@ static ssize_t get_target(struct device *dev, struct device_attribute *devattr,
return sprintf(buf, "%d\n", rpm);
}
static ssize_t set_target(struct device *dev, struct device_attribute *devattr,
const char *buf, size_t count)
static int max6650_set_target(struct max6650_data *data, unsigned long rpm)
{
struct max6650_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
int kscale, ktach;
unsigned long rpm;
int err;
err = kstrtoul(buf, 10, &rpm);
if (err)
return err;
if (rpm == 0)
return max6650_set_operating_mode(data, MAX6650_CFG_MODE_OFF);
rpm = clamp_val(rpm, FAN_RPM_MIN, FAN_RPM_MAX);
@ -288,8 +306,6 @@ static ssize_t set_target(struct device *dev, struct device_attribute *devattr,
* KTACH = [(fCLK x KSCALE) / (256 x FanSpeed)] - 1
*/
mutex_lock(&data->update_lock);
kscale = DIV_FROM_REG(data->config);
ktach = ((clock * kscale) / (256 * rpm / 60)) - 1;
if (ktach < 0)
@ -298,10 +314,30 @@ static ssize_t set_target(struct device *dev, struct device_attribute *devattr,
ktach = 255;
data->speed = ktach;
i2c_smbus_write_byte_data(client, MAX6650_REG_SPEED, data->speed);
return i2c_smbus_write_byte_data(data->client, MAX6650_REG_SPEED,
data->speed);
}
static ssize_t set_target(struct device *dev, struct device_attribute *devattr,
const char *buf, size_t count)
{
struct max6650_data *data = dev_get_drvdata(dev);
unsigned long rpm;
int err;
err = kstrtoul(buf, 10, &rpm);
if (err)
return err;
mutex_lock(&data->update_lock);
err = max6650_set_target(data, rpm);
mutex_unlock(&data->update_lock);
if (err < 0)
return err;
return count;
}
@ -355,12 +391,11 @@ static ssize_t set_pwm(struct device *dev, struct device_attribute *devattr,
data->dac = 180 - (180 * pwm)/255;
else
data->dac = 76 - (76 * pwm)/255;
i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, data->dac);
err = i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, data->dac);
mutex_unlock(&data->update_lock);
return count;
return err < 0 ? err : count;
}
/*
@ -369,14 +404,14 @@ static ssize_t set_pwm(struct device *dev, struct device_attribute *devattr,
* 0 = Fan always on
* 1 = Open loop, Voltage is set according to speed, not regulated.
* 2 = Closed loop, RPM for all fans regulated by fan1 tachometer
* 3 = Fan off
*/
static ssize_t get_enable(struct device *dev, struct device_attribute *devattr,
char *buf)
{
struct max6650_data *data = max6650_update_device(dev);
int mode = (data->config & MAX6650_CFG_MODE_MASK) >> 4;
int sysfs_modes[4] = {0, 1, 2, 1};
int sysfs_modes[4] = {0, 3, 2, 1};
return sprintf(buf, "%d\n", sysfs_modes[mode]);
}
@ -385,25 +420,25 @@ static ssize_t set_enable(struct device *dev, struct device_attribute *devattr,
const char *buf, size_t count)
{
struct max6650_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
int max6650_modes[3] = {0, 3, 2};
unsigned long mode;
int err;
const u8 max6650_modes[] = {
MAX6650_CFG_MODE_ON,
MAX6650_CFG_MODE_OPEN_LOOP,
MAX6650_CFG_MODE_CLOSED_LOOP,
MAX6650_CFG_MODE_OFF,
};
err = kstrtoul(buf, 10, &mode);
if (err)
return err;
if (mode > 2)
if (mode >= ARRAY_SIZE(max6650_modes))
return -EINVAL;
mutex_lock(&data->update_lock);
data->config = i2c_smbus_read_byte_data(client, MAX6650_REG_CONFIG);
data->config = (data->config & ~MAX6650_CFG_MODE_MASK)
| (max6650_modes[mode] << 4);
i2c_smbus_write_byte_data(client, MAX6650_REG_CONFIG, data->config);
max6650_set_operating_mode(data, max6650_modes[mode]);
mutex_unlock(&data->update_lock);
@ -582,6 +617,7 @@ static int max6650_init_client(struct max6650_data *data,
int err = -EIO;
u32 voltage;
u32 prescale;
u32 target_rpm;
if (of_property_read_u32(dev->of_node, "maxim,fan-microvolt",
&voltage))
@ -642,22 +678,6 @@ static int max6650_init_client(struct max6650_data *data,
(config & MAX6650_CFG_V12) ? 12 : 5,
1 << (config & MAX6650_CFG_PRESCALER_MASK));
/*
* If mode is set to "full off", we change it to "open loop" and
* set DAC to 255, which has the same effect. We do this because
* there's no "full off" mode defined in hwmon specifications.
*/
if ((config & MAX6650_CFG_MODE_MASK) == MAX6650_CFG_MODE_OFF) {
dev_dbg(dev, "Change mode to open loop, full off.\n");
config = (config & ~MAX6650_CFG_MODE_MASK)
| MAX6650_CFG_MODE_OPEN_LOOP;
if (i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, 255)) {
dev_err(dev, "DAC write error, aborting.\n");
return err;
}
}
if (i2c_smbus_write_byte_data(client, MAX6650_REG_CONFIG, config)) {
dev_err(dev, "Config write error, aborting.\n");
return err;
@ -666,6 +686,12 @@ static int max6650_init_client(struct max6650_data *data,
data->config = config;
data->count = i2c_smbus_read_byte_data(client, MAX6650_REG_COUNT);
if (!of_property_read_u32(client->dev.of_node, "maxim,fan-target-rpm",
&target_rpm)) {
max6650_set_target(data, target_rpm);
max6650_set_operating_mode(data, MAX6650_CFG_MODE_CLOSED_LOOP);
}
return 0;
}