hwmon: (corsair-psu) add support for reading PWM values and mode

Add support for reading PWM values and mode,
and update documentation accordingly.

Signed-off-by: Wilken Gottwalt <wilken.gottwalt@posteo.net>
Link: https://lore.kernel.org/r/ZJSASByXpzoZ0XyH@monster.localdomain
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/Documentation/hwmon/corsair-psu.rst b/Documentation/hwmon/corsair-psu.rst
index c389bd2..fc798c3 100644 (file)
--- a/Documentation/hwmon/corsair-psu.rst
+++ b/Documentation/hwmon/corsair-psu.rst
@@ -69,6 +69,8 @@ power1_input          Total power usage
 power2_input           Power usage of the 12v psu rail
 power3_input           Power usage of the 5v psu rail
 power4_input           Power usage of the 3.3v psu rail
+pwm1                   PWM value, read only
+pwm1_enable            PWM mode, read only
 temp1_input            Temperature of the psu vrm component
 temp1_crit             Temperature max cirtical value of the psu vrm component
 temp2_input            Temperature of the psu case

diff --git a/drivers/hwmon/corsair-psu.c b/drivers/hwmon/corsair-psu.c
index dc24c56..2389f60 100644 (file)
--- a/drivers/hwmon/corsair-psu.c
+++ b/drivers/hwmon/corsair-psu.c
@@ -58,7 +58,8 @@
 #define OCP_MULTI_RAIL         0x02
 
 #define PSU_CMD_SELECT_RAIL    0x00 /* expects length 2 */
-#define PSU_CMD_RAIL_VOLTS_HCRIT 0x40 /* the rest of the commands expect length 3 */
+#define PSU_CMD_FAN_PWM                0x3B /* the rest of the commands expect length 3 */
+#define PSU_CMD_RAIL_VOLTS_HCRIT 0x40
 #define PSU_CMD_RAIL_VOLTS_LCRIT 0x44
 #define PSU_CMD_RAIL_AMPS_HCRIT        0x46
 #define PSU_CMD_TEMP_HCRIT     0x4F
@@ -76,6 +77,7 @@
 #define PSU_CMD_UPTIME         0xD2
 #define PSU_CMD_OCPMODE                0xD8
 #define PSU_CMD_TOTAL_WATTS    0xEE
+#define PSU_CMD_FAN_PWM_ENABLE 0xF0
 #define PSU_CMD_INIT           0xFE
 
 #define L_IN_VOLTS             "v_in"
@@ -145,6 +147,14 @@ static int corsairpsu_linear11_to_int(const u16 val, const int scale)
        return (exp >= 0) ? (result << exp) : (result >> -exp);
 }
 
+/* the micro-controller uses percentage values to control pwm */
+static int corsairpsu_dutycycle_to_pwm(const long dutycycle)
+{
+       const int result = (256 << 16) / 100;
+
+       return (result * dutycycle) >> 16;
+}
+
 static int corsairpsu_usb_cmd(struct corsairpsu_data *priv, u8 p0, u8 p1, u8 p2, void *data)
 {
        unsigned long time;
@@ -264,6 +274,24 @@ static int corsairpsu_get_value(struct corsairpsu_data *priv, u8 cmd, u8 rail, l
        case PSU_CMD_FAN:
                *val = corsairpsu_linear11_to_int(tmp & 0xFFFF, 1);
                break;
+       case PSU_CMD_FAN_PWM_ENABLE:
+               *val = corsairpsu_linear11_to_int(tmp & 0xFFFF, 1);
+               /*
+                * 0 = automatic mode, means the micro-controller controls the fan using a plan
+                *     which can be modified, but changing this plan is not supported by this
+                *     driver, the matching PWM mode is automatic fan speed control = PWM 2
+                * 1 = fixed mode, fan runs at a fixed speed represented by a percentage
+                *     value 0-100, this matches the PWM manual fan speed control = PWM 1
+                * technically there is no PWM no fan speed control mode, it would be a combination
+                * of 1 at 100%
+                */
+               if (*val == 0)
+                       *val = 2;
+               break;
+       case PSU_CMD_FAN_PWM:
+               *val = corsairpsu_linear11_to_int(tmp & 0xFFFF, 1);
+               *val = corsairpsu_dutycycle_to_pwm(*val);
+               break;
        case PSU_CMD_RAIL_WATTS:
        case PSU_CMD_TOTAL_WATTS:
                *val = corsairpsu_linear11_to_int(tmp & 0xFFFF, 1000000);
@@ -349,6 +377,18 @@ static umode_t corsairpsu_hwmon_fan_is_visible(const struct corsairpsu_data *pri
        }
 }
 
+static umode_t corsairpsu_hwmon_pwm_is_visible(const struct corsairpsu_data *priv, u32 attr,
+                                              int channel)
+{
+       switch (attr) {
+       case hwmon_pwm_input:
+       case hwmon_pwm_enable:
+               return 0444;
+       default:
+               return 0;
+       }
+}
+
 static umode_t corsairpsu_hwmon_power_is_visible(const struct corsairpsu_data *priv, u32 attr,
                                                 int channel)
 {
@@ -416,6 +456,8 @@ static umode_t corsairpsu_hwmon_ops_is_visible(const void *data, enum hwmon_sens
                return corsairpsu_hwmon_temp_is_visible(priv, attr, channel);
        case hwmon_fan:
                return corsairpsu_hwmon_fan_is_visible(priv, attr, channel);
+       case hwmon_pwm:
+               return corsairpsu_hwmon_pwm_is_visible(priv, attr, channel);
        case hwmon_power:
                return corsairpsu_hwmon_power_is_visible(priv, attr, channel);
        case hwmon_in:
@@ -447,6 +489,20 @@ static int corsairpsu_hwmon_temp_read(struct corsairpsu_data *priv, u32 attr, in
        return err;
 }
 
+static int corsairpsu_hwmon_pwm_read(struct corsairpsu_data *priv, u32 attr, int channel, long *val)
+{
+       switch (attr) {
+       case hwmon_pwm_input:
+               return corsairpsu_get_value(priv, PSU_CMD_FAN_PWM, 0, val);
+       case hwmon_pwm_enable:
+               return corsairpsu_get_value(priv, PSU_CMD_FAN_PWM_ENABLE, 0, val);
+       default:
+               break;
+       }
+
+       return -EOPNOTSUPP;
+}
+
 static int corsairpsu_hwmon_power_read(struct corsairpsu_data *priv, u32 attr, int channel,
                                       long *val)
 {
@@ -531,6 +587,8 @@ static int corsairpsu_hwmon_ops_read(struct device *dev, enum hwmon_sensor_types
                if (attr == hwmon_fan_input)
                        return corsairpsu_get_value(priv, PSU_CMD_FAN, 0, val);
                return -EOPNOTSUPP;
+       case hwmon_pwm:
+               return corsairpsu_hwmon_pwm_read(priv, attr, channel, val);
        case hwmon_power:
                return corsairpsu_hwmon_power_read(priv, attr, channel, val);
        case hwmon_in:
@@ -579,6 +637,8 @@ static const struct hwmon_channel_info * const corsairpsu_info[] = {
                           HWMON_T_INPUT | HWMON_T_LABEL | HWMON_T_CRIT),
        HWMON_CHANNEL_INFO(fan,
                           HWMON_F_INPUT | HWMON_F_LABEL),
+       HWMON_CHANNEL_INFO(pwm,
+                          HWMON_PWM_INPUT | HWMON_PWM_ENABLE),
        HWMON_CHANNEL_INFO(power,
                           HWMON_P_INPUT | HWMON_P_LABEL,
                           HWMON_P_INPUT | HWMON_P_LABEL,