mlxsw: core: Implement fan control using hwmon

ASIC provides access to fans. Implement their exposure to userspace
using hwmon.
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/core_hwmon.c

@@ -42,7 +42,8 @@
 #include "core.h"
 
 #define MLXSW_HWMON_TEMP_SENSOR_MAX_COUNT 127
-#define MLXSW_HWMON_ATTR_COUNT (MLXSW_HWMON_TEMP_SENSOR_MAX_COUNT * 4)
+#define MLXSW_HWMON_ATTR_COUNT (MLXSW_HWMON_TEMP_SENSOR_MAX_COUNT * 4 + \
+				MLXSW_MFCR_TACHOS_MAX + MLXSW_MFCR_PWMS_MAX)
 
 struct mlxsw_hwmon_attr {
 	struct device_attribute dev_attr;
@@ -106,9 +107,76 @@ static ssize_t mlxsw_hwmon_temp_max_show(struct device *dev,
 	return sprintf(buf, "%u\n", temp_max);
 }
 
+static ssize_t mlxsw_hwmon_fan_rpm_show(struct device *dev,
+					struct device_attribute *attr,
+					char *buf)
+{
+	struct mlxsw_hwmon_attr *mlwsw_hwmon_attr =
+			container_of(attr, struct mlxsw_hwmon_attr, dev_attr);
+	struct mlxsw_hwmon *mlxsw_hwmon = mlwsw_hwmon_attr->hwmon;
+	char mfsm_pl[MLXSW_REG_MFSM_LEN];
+	int err;
+
+	mlxsw_reg_mfsm_pack(mfsm_pl, mlwsw_hwmon_attr->type_index);
+	err = mlxsw_reg_query(mlxsw_hwmon->core, MLXSW_REG(mfsm), mfsm_pl);
+	if (err) {
+		dev_err(mlxsw_hwmon->bus_info->dev, "Failed to query fan\n");
+		return err;
+	}
+	return sprintf(buf, "%u\n", mlxsw_reg_mfsm_rpm_get(mfsm_pl));
+}
+
+static ssize_t mlxsw_hwmon_pwm_show(struct device *dev,
+				    struct device_attribute *attr,
+				    char *buf)
+{
+	struct mlxsw_hwmon_attr *mlwsw_hwmon_attr =
+			container_of(attr, struct mlxsw_hwmon_attr, dev_attr);
+	struct mlxsw_hwmon *mlxsw_hwmon = mlwsw_hwmon_attr->hwmon;
+	char mfsc_pl[MLXSW_REG_MFSC_LEN];
+	int err;
+
+	mlxsw_reg_mfsc_pack(mfsc_pl, mlwsw_hwmon_attr->type_index, 0);
+	err = mlxsw_reg_query(mlxsw_hwmon->core, MLXSW_REG(mfsc), mfsc_pl);
+	if (err) {
+		dev_err(mlxsw_hwmon->bus_info->dev, "Failed to query PWM\n");
+		return err;
+	}
+	return sprintf(buf, "%u\n",
+		       mlxsw_reg_mfsc_pwm_duty_cycle_get(mfsc_pl));
+}
+
+static ssize_t mlxsw_hwmon_pwm_store(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf, size_t len)
+{
+	struct mlxsw_hwmon_attr *mlwsw_hwmon_attr =
+			container_of(attr, struct mlxsw_hwmon_attr, dev_attr);
+	struct mlxsw_hwmon *mlxsw_hwmon = mlwsw_hwmon_attr->hwmon;
+	char mfsc_pl[MLXSW_REG_MFSC_LEN];
+	unsigned long val;
+	int err;
+
+	err = kstrtoul(buf, 10, &val);
+	if (err)
+		return err;
+	if (val > 255)
+		return -EINVAL;
+
+	mlxsw_reg_mfsc_pack(mfsc_pl, mlwsw_hwmon_attr->type_index, val);
+	err = mlxsw_reg_write(mlxsw_hwmon->core, MLXSW_REG(mfsc), mfsc_pl);
+	if (err) {
+		dev_err(mlxsw_hwmon->bus_info->dev, "Failed to write PWM\n");
+		return err;
+	}
+	return err ? err : len;
+}
+
 enum mlxsw_hwmon_attr_type {
 	MLXSW_HWMON_ATTR_TYPE_TEMP,
 	MLXSW_HWMON_ATTR_TYPE_TEMP_MAX,
+	MLXSW_HWMON_ATTR_TYPE_FAN_RPM,
+	MLXSW_HWMON_ATTR_TYPE_PWM,
 };
 
 static void mlxsw_hwmon_attr_add(struct mlxsw_hwmon *mlxsw_hwmon,
@@ -133,6 +201,19 @@ static void mlxsw_hwmon_attr_add(struct mlxsw_hwmon *mlxsw_hwmon,
 		snprintf(mlxsw_hwmon_attr->name, sizeof(mlxsw_hwmon_attr->name),
 			 "temp%u_highest", num + 1);
 		break;
+	case MLXSW_HWMON_ATTR_TYPE_FAN_RPM:
+		mlxsw_hwmon_attr->dev_attr.show = mlxsw_hwmon_fan_rpm_show;
+		mlxsw_hwmon_attr->dev_attr.attr.mode = S_IRUGO;
+		snprintf(mlxsw_hwmon_attr->name, sizeof(mlxsw_hwmon_attr->name),
+			 "fan%u_input", num + 1);
+		break;
+	case MLXSW_HWMON_ATTR_TYPE_PWM:
+		mlxsw_hwmon_attr->dev_attr.show = mlxsw_hwmon_pwm_show;
+		mlxsw_hwmon_attr->dev_attr.store = mlxsw_hwmon_pwm_store;
+		mlxsw_hwmon_attr->dev_attr.attr.mode = S_IWUSR | S_IRUGO;
+		snprintf(mlxsw_hwmon_attr->name, sizeof(mlxsw_hwmon_attr->name),
+			 "pwm%u", num + 1);
+		break;
 	default:
 		BUG();
 	}
@@ -177,6 +258,39 @@ static int mlxsw_hwmon_temp_init(struct mlxsw_hwmon *mlxsw_hwmon)
 	return 0;
 }
 
+static int mlxsw_hwmon_fans_init(struct mlxsw_hwmon *mlxsw_hwmon)
+{
+	char mfcr_pl[MLXSW_REG_MFCR_LEN];
+	enum mlxsw_reg_mfcr_pwm_frequency freq;
+	unsigned int type_index;
+	unsigned int num;
+	u16 tacho_active;
+	u8 pwm_active;
+	int err;
+
+	err = mlxsw_reg_query(mlxsw_hwmon->core, MLXSW_REG(mfcr), mfcr_pl);
+	if (err) {
+		dev_err(mlxsw_hwmon->bus_info->dev, "Failed to get to probe PWMs and Tachometers\n");
+		return err;
+	}
+	mlxsw_reg_mfcr_unpack(mfcr_pl, &freq, &tacho_active, &pwm_active);
+	num = 0;
+	for (type_index = 0; type_index < MLXSW_MFCR_TACHOS_MAX; type_index++) {
+		if (tacho_active & BIT(type_index))
+			mlxsw_hwmon_attr_add(mlxsw_hwmon,
+					     MLXSW_HWMON_ATTR_TYPE_FAN_RPM,
+					     type_index, num++);
+	}
+	num = 0;
+	for (type_index = 0; type_index < MLXSW_MFCR_PWMS_MAX; type_index++) {
+		if (pwm_active & BIT(type_index))
+			mlxsw_hwmon_attr_add(mlxsw_hwmon,
+					     MLXSW_HWMON_ATTR_TYPE_PWM,
+					     type_index, num++);
+	}
+	return 0;
+}
+
 int mlxsw_hwmon_init(struct mlxsw_core *mlxsw_core,
 		     const struct mlxsw_bus_info *mlxsw_bus_info,
 		     struct mlxsw_hwmon **p_hwmon)
@@ -195,6 +309,10 @@ int mlxsw_hwmon_init(struct mlxsw_core *mlxsw_core,
 	if (err)
 		goto err_temp_init;
 
+	err = mlxsw_hwmon_fans_init(mlxsw_hwmon);
+	if (err)
+		goto err_fans_init;
+
 	mlxsw_hwmon->groups[0] = &mlxsw_hwmon->group;
 	mlxsw_hwmon->group.attrs = mlxsw_hwmon->attrs;
 
@@ -212,6 +330,7 @@ int mlxsw_hwmon_init(struct mlxsw_core *mlxsw_core,
 	return 0;
 
 err_hwmon_register:
+err_fans_init:
 err_temp_init:
 	kfree(mlxsw_hwmon);
 	return err;