[PATCH v2 04/11] hwmon: (amc6821) Add support for fan1_target and pwm1_enable mode 4

Guenter Roeck
2024-07-01T21:23:58Z

After setting fan1_target and setting pwm1_enable to 4,
the fan controller tries to achieve the requested fan speed.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v2: Do not permit writing negative or unlimited target fan speed

Documentation/hwmon/amc6821.rst | 4 ++++
drivers/hwmon/amc6821.c | 25 +++++++++++++++++--------
2 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/Documentation/hwmon/amc6821.rst b/Documentation/hwmon/amc6821.rst
index 4ce67c268e52..96e604c5ea8e 100644
--- a/Documentation/hwmon/amc6821.rst
+++ b/Documentation/hwmon/amc6821.rst
@@ -48,12 +48,16 @@ fan1_min rw "
fan1_max rw "
fan1_fault ro "
fan1_pulses rw Pulses per revolution can be either 2 or 4.
+fan1_target rw Target fan speed, to be used with pwm1_enable
+ mode 4.

pwm1 rw pwm1
pwm1_enable rw regulator mode, 1=open loop, 2=fan controlled
by remote temperature, 3=fan controlled by
combination of the on-chip temperature and
remote-sensor temperature,
+ 4=fan controlled by target rpm set with
+ fan1_target attribute.
pwm1_auto_channels_temp ro 1 if pwm_enable==2, 3 if pwm_enable==3
pwm1_auto_point1_pwm ro Hardwired to 0, shared for both
temperature channels.
diff --git a/drivers/hwmon/amc6821.c b/drivers/hwmon/amc6821.c
index ed98d470a308..caf720ff674c 100644
--- a/drivers/hwmon/amc6821.c
+++ b/drivers/hwmon/amc6821.c
@@ -66,6 +66,8 @@ enum chips { amc6821 };
#define AMC6821_REG_TACH_LLIMITH 0x11
#define AMC6821_REG_TACH_HLIMITL 0x12
#define AMC6821_REG_TACH_HLIMITH 0x13
+#define AMC6821_REG_TACH_SETTINGL 0x1e
+#define AMC6821_REG_TACH_SETTINGH 0x1f

#define AMC6821_CONF1_START 0x01
#define AMC6821_CONF1_FAN_INT_EN 0x02
@@ -122,17 +124,18 @@ static const u8 temp_reg[] = {AMC6821_REG_LTEMP_HI,
AMC6821_REG_RTEMP_LIMIT_MAX,
AMC6821_REG_RTEMP_CRIT, };

-enum {IDX_FAN1_INPUT = 0, IDX_FAN1_MIN, IDX_FAN1_MAX,
+enum {IDX_FAN1_INPUT = 0, IDX_FAN1_MIN, IDX_FAN1_MAX, IDX_FAN1_TARGET,
FAN1_IDX_LEN, };

static const u8 fan_reg_low[] = {AMC6821_REG_TDATA_LOW,
AMC6821_REG_TACH_LLIMITL,
- AMC6821_REG_TACH_HLIMITL, };
-
+ AMC6821_REG_TACH_HLIMITL,
+ AMC6821_REG_TACH_SETTINGL, };

static const u8 fan_reg_hi[] = {AMC6821_REG_TDATA_HI,
AMC6821_REG_TACH_LLIMITH,
- AMC6821_REG_TACH_HLIMITH, };
+ AMC6821_REG_TACH_HLIMITH,
+ AMC6821_REG_TACH_SETTINGH, };

/*
* Client data (each client gets its own)
@@ -250,10 +253,10 @@ static struct amc6821_data *amc6821_update_device(struct device *dev)
break;
case 1: /*
* semi-open loop: software sets rpm, chip controls
- * pwm1, currently not implemented
+ * pwm1
*/
data->pwm1_auto_channels_temp = 0;
- data->pwm1_enable = 0;
+ data->pwm1_enable = 4;
break;
}

@@ -407,6 +410,10 @@ static ssize_t pwm1_enable_store(struct device *dev,
config |= AMC6821_CONF1_FDRC0;
config |= AMC6821_CONF1_FDRC1;
break;
+ case 4:
+ config |= AMC6821_CONF1_FDRC0;
+ config &= ~AMC6821_CONF1_FDRC1;
+ break;
default:
count = -EINVAL;
goto unlock;
@@ -623,8 +630,8 @@ static ssize_t fan_store(struct device *dev, struct device_attribute *attr,
if (ret)
return ret;

- /* The minimum fan speed must not be unlimited (0) */
- if (ix == IDX_FAN1_MIN && !val)
+ /* Minimum and target fan speed must not be unlimited (0) */
+ if ((ix == IDX_FAN1_MIN || ix == IDX_FAN1_TARGET) && !val)
return -EINVAL;

val = val > 0 ? 6000000 / clamp_val(val, 1, 6000000) : 0;
@@ -714,6 +721,7 @@ static SENSOR_DEVICE_ATTR_RO(temp2_crit_alarm, temp_alarm, IDX_TEMP2_CRIT);
static SENSOR_DEVICE_ATTR_RO(fan1_input, fan, IDX_FAN1_INPUT);
static SENSOR_DEVICE_ATTR_RW(fan1_min, fan, IDX_FAN1_MIN);
static SENSOR_DEVICE_ATTR_RW(fan1_max, fan, IDX_FAN1_MAX);
+static SENSOR_DEVICE_ATTR_RW(fan1_target, fan, IDX_FAN1_TARGET);
static SENSOR_DEVICE_ATTR_RO(fan1_fault, fan1_fault, 0);
static SENSOR_DEVICE_ATTR_RW(fan1_pulses, fan1_pulses, 0);

@@ -757,6 +765,7 @@ static struct attribute *amc6821_attrs[] = {
&sensor_dev_attr_fan1_input.dev_attr.attr,
&sensor_dev_attr_fan1_min.dev_attr.attr,
&sensor_dev_attr_fan1_max.dev_attr.attr,
+ &sensor_dev_attr_fan1_target.dev_attr.attr,
&sensor_dev_attr_fan1_fault.dev_attr.attr,
&sensor_dev_attr_fan1_pulses.dev_attr.attr,
&sensor_dev_attr_pwm1.dev_attr.attr,
--
2.39.2