oxp-sensors: hwmon: Add GPD Win Mini

Add GPD Win Mini. GPD devices don't have a separate enable register, the PWM
register is used for this purpose. A write value of 0 puts the PWM into auto
mode, writing anything 1-244 puts the PWM into manual mode, and 245-255 are
undefined. We scale to 1-255 and handle manual by writing a value to 70% as a
common sense default.

drivers/hwmon/oxp-sensors.c

@@ -50,6 +50,7 @@ enum oxp_board {
 	aya_neo_geek,
 	aya_neo_geek_1s,
 	aya_neo_kun,
+	gpd_win_mini,
 	orange_pi_neo,
 	oxp_2,
 	oxp_fly,
@@ -69,8 +70,19 @@ static enum oxp_board board;
 #define ORANGEPI_SENSOR_PWM_ENABLE_REG  0x40 /* PWM enable is 1 register long */
 #define ORANGEPI_SENSOR_PWM_REG         0x38 /* PWM reading is 1 register long */
 
+/* GPD devices don't have a separate enable register for the fan.
+ * For the PWM register, 0 is auto, 1+ is a manual value, up to 255
+ * depending on the specific model. This driver will scale to 0-255
+ * and treat PWM enable without a value as "set to manual, 70%."
+ * The mini uses the same fan register as the OrangePi NEO.
+ */
+#define GPD_MINI_SENSOR_PWM_REG         0x7A /* PWM reading is 1 register long */
+/* Values for fan auto mode */
 #define PWM_MODE_AUTO                   0x00
+
+ /* Values for fan manual mode */
 #define PWM_MODE_MANUAL                 0x01
+#define GPD_MINI_PWM_MODE_MANUAL        0xAA /* 70% */
 /* Turbo button takeover function
  * Different boards have different values and EC registers
  * for the same function
@@ -161,6 +173,13 @@ static const struct dmi_system_id dmi_table[] = {
 		},
 		.driver_data = (void *)aya_neo_kun,
 	},
+	{
+		.matches = {
+			DMI_MATCH(DMI_BOARD_VENDOR, "GPD"),
+			DMI_EXACT_MATCH(DMI_BOARD_NAME, "G1617-01"),
+		},
+		.driver_data = (void *)gpd_win_mini,
+	},
 	{
 		.matches = {
 			DMI_MATCH(DMI_BOARD_VENDOR, "OrangePi"),
@@ -388,6 +407,11 @@ static DEVICE_ATTR_RW(tt_toggle);
 static int oxp_pwm_enable(void)
 {
 	switch (board) {
+	/* GPD has no separate enable register, instead, set the fan to
+	 * a safe default.
+	 */
+	case gpd_win_mini:
+		return write_to_ec(GPD_MINI_SENSOR_PWM_REG, GPD_MINI_PWM_MODE_MANUAL);
 	case orange_pi_neo:
 		return write_to_ec(ORANGEPI_SENSOR_PWM_ENABLE_REG, PWM_MODE_MANUAL);
 	case aok_zoe_a1:
@@ -414,6 +438,8 @@ static int oxp_pwm_enable(void)
 static int oxp_pwm_disable(void)
 {
 	switch (board) {
+	case gpd_win_mini:
+		return write_to_ec(GPD_MINI_SENSOR_PWM_REG, PWM_MODE_AUTO);
 	case orange_pi_neo:
 		return write_to_ec(ORANGEPI_SENSOR_PWM_ENABLE_REG, PWM_MODE_AUTO);
 	case aok_zoe_a1:
@@ -461,6 +487,7 @@ static int oxp_platform_read(struct device *dev, enum hwmon_sensor_types type,
 		switch (attr) {
 		case hwmon_fan_input:
 			switch (board) {
+			case gpd_win_mini:
 			case orange_pi_neo:
 				return read_from_ec(ORANGEPI_SENSOR_FAN_REG, 2, val);
 			case aok_zoe_a1:
@@ -490,6 +517,14 @@ static int oxp_platform_read(struct device *dev, enum hwmon_sensor_types type,
 		switch (attr) {
 		case hwmon_pwm_input:
 			switch (board) {
+			case gpd_win_mini:
+				ret = read_from_ec(GPD_MINI_SENSOR_PWM_REG, 1, val);
+				if (ret)
+					return ret;
+				if (*val != PWM_MODE_AUTO)
+					/* scale from range [1-244] */
+					*val = ((*val - 1) * 254 / 243) + 1;
+				break;
 			case orange_pi_neo:
 				ret = read_from_ec(ORANGEPI_SENSOR_PWM_REG, 1, val);
 				if (ret)
@@ -522,6 +557,10 @@ static int oxp_platform_read(struct device *dev, enum hwmon_sensor_types type,
 			return 0;
 		case hwmon_pwm_enable:
 			switch (board) {
+			case gpd_win_mini:
+				ret = read_from_ec(GPD_MINI_SENSOR_PWM_REG, 1, val);
+				*val = (*val != PWM_MODE_AUTO);
+				return ret;
 			case orange_pi_neo:
 				return read_from_ec(ORANGEPI_SENSOR_PWM_ENABLE_REG, 1, val);
 			case aok_zoe_a1:
@@ -569,6 +608,10 @@ static int oxp_platform_write(struct device *dev, enum hwmon_sensor_types type,
 			if (val < 0 || val > 255)
 				return -EINVAL;
 			switch (board) {
+			case gpd_win_mini:
+				/* scale to range [1-244] */
+				val = ((val - 1) * 243 / 254) + 1;
+				return write_to_ec(GPD_MINI_SENSOR_PWM_REG, val);
 			case orange_pi_neo:
 				/* scale to range [1-244] */
 				val = ((val - 1) * 243 / 254) + 1;