Attempt at becoming a ssam device driver.

drivers/platform/surface/surface_fan.c

@@ -5,7 +5,6 @@
  * Copyright (C) 2023 Ivor Wanders <ivor@iwanders.net>
  */
 
-#include <linux/acpi.h>
 #include <linux/hwmon.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
@@ -14,9 +13,7 @@
 #include <linux/thermal.h>
 #include <linux/types.h>
 
-// This is a non-SSAM client driver as per the surface documentation.
-// It registers itself as an ACPI driver for PNP0C0B, which requires removing
-// the default fan module.
+// This is a SSAM client driver as per the surface documentation.
 // It both sets up as a cooling device through the thermal cooling device as
 // well as a hwmon fan for monitoring.
 
@@ -29,10 +26,10 @@
 
 struct fan_data {
 	struct device *dev;
-	struct ssam_controller *ctrl;
-	struct acpi_device *acpi_fan;
-
 	struct thermal_cooling_device *cdev;
+
+	struct ssam_device *sdev;
+
 	struct device *hdev;
 };
 
@@ -51,13 +48,6 @@ SSAM_DEFINE_SYNC_REQUEST_R(__ssam_fan_get, __le16, {
 	.instance_id     = 0x01,
 });
 
-// ACPI
-static const struct acpi_device_id surface_fan_match[] = {
-	{ "PNP0C0B" },
-	{},
-};
-MODULE_DEVICE_TABLE(acpi, surface_fan_match);
-
 
 // Thermal cooling device
 static int surface_fan_set_cur_state(struct thermal_cooling_device *cdev,
@@ -66,7 +56,7 @@ static int surface_fan_set_cur_state(struct thermal_cooling_device *cdev,
 	__le16 value;
 	struct fan_data *d = cdev->devdata;
 	value = cpu_to_le16(clamp(state, 0lu, (1lu << 16)));
-	return __ssam_fan_set(d->ctrl, &value);
+	return __ssam_fan_set(d->sdev->ctrl, &value);
 }
 
 static int surface_fan_get_cur_state(struct thermal_cooling_device *cdev,
@@ -75,7 +65,7 @@ static int surface_fan_get_cur_state(struct thermal_cooling_device *cdev,
 	int res;
 	struct fan_data *d = cdev->devdata;
 	__le16 value = 0;
-	res = __ssam_fan_get(d->ctrl, &value);
+	res = __ssam_fan_get(d->sdev->ctrl, &value);
 	*state = le16_to_cpu(value);
 	return res;
 }
@@ -121,15 +111,15 @@ static int surface_fan_hwmon_read(struct device *dev,
 					enum hwmon_sensor_types type,
 					u32 attr, int channel, long *val)
 {
-	struct fan_data *data = dev_get_drvdata(dev);
+	struct fan_data *d = dev_get_drvdata(dev);
 	__le16 value;
 	int res;
 
 	switch (type) {
 	case hwmon_fan:
 		switch (attr) {
 		case hwmon_fan_input:
-			res = __ssam_fan_get(data->ctrl, &value);
+			res = __ssam_fan_get(d->sdev->ctrl, &value);
 			if (res) {
 				return -1;
 			} 
@@ -161,14 +151,14 @@ static int surface_fan_hwmon_write(struct device *dev,
 					u32 attr, int channel, long val)
 {
 	__le16 value;
-	struct fan_data *data = dev_get_drvdata(dev);
+	struct fan_data *d = dev_get_drvdata(dev);
 
 	switch (type) {
 	case hwmon_fan:
 		switch (attr) {
 		case hwmon_fan_target:
 			value = cpu_to_le16(clamp(val, 0l, (1l << 16)));
-			return __ssam_fan_set(data->ctrl, &value);
+			return __ssam_fan_set(d->sdev->ctrl, &value);
 		default:
 			break;
 		}
@@ -200,29 +190,23 @@ static const struct hwmon_chip_info surface_fan_chip_info = {
 	.info = surface_fan_info,
 };
 
-static int surface_fan_probe(struct platform_device *pdev)
+static int surface_fan_probe(struct ssam_device *sdev)
 {
-	struct acpi_device *acpi_fan = ACPI_COMPANION(&pdev->dev);
-
-	struct ssam_controller *ctrl;
 	struct fan_data *data;
 	struct thermal_cooling_device *cdev;
 	struct device *hdev;
 	__le16 value;
 	int status;
 
-	ctrl = ssam_client_bind(&pdev->dev);
-	if (IS_ERR(ctrl))
-		return PTR_ERR(ctrl) == -ENODEV ? -EPROBE_DEFER : PTR_ERR(ctrl);
-
+	printk(KERN_INFO "In probe!");
 	// Probe the fan to confirm we actually have it by retrieving the 
 	// speed.
-	status = __ssam_fan_get(ctrl, &value);
+	status = __ssam_fan_get(sdev->ctrl, &value);
 	if (status) {
 		return -ENODEV;
 	}
 
-	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+	data = devm_kzalloc(&sdev->dev, sizeof(*data), GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;
 
@@ -232,55 +216,45 @@ static int surface_fan_probe(struct platform_device *pdev)
 		return PTR_ERR(cdev);
 
 
-	hdev = devm_hwmon_device_register_with_info(&pdev->dev, "fan", data,
+	hdev = devm_hwmon_device_register_with_info(&sdev->dev, "fan", data,
 							&surface_fan_chip_info,
 							NULL);
 	if (IS_ERR(hdev)) {
 		return PTR_ERR(hdev);
 	}
 
-	data->dev = &pdev->dev;
-	data->ctrl = ctrl;
-	data->acpi_fan = acpi_fan;
-
+	data->sdev = sdev;
 	data->cdev = cdev;
 	data->hdev = hdev;
 
-	acpi_fan->driver_data = data;
-	platform_set_drvdata(pdev, data);
+	ssam_device_set_drvdata(sdev, data);
 
 	return 0;
 }
 
-static int surface_fan_remove(struct platform_device *pdev)
+static void surface_fan_remove(struct ssam_device *sdev)
 {
-	struct fan_data *d = platform_get_drvdata(pdev);
+	struct fan_data *d = ssam_device_get_drvdata(sdev);
 	thermal_cooling_device_unregister(d->cdev);
-	return 0;
 }
 
 
-static struct platform_driver surface_fan = {
+static const struct ssam_device_id ssam_fan_match[] = {
+	{ SSAM_SDEV(FAN, SAM, SSAM_SSH_IID_ANY, SSAM_SSH_FUN_ANY) },
+	{ },
+};
+MODULE_DEVICE_TABLE(ssam, ssam_fan_match);
+
+static struct ssam_device_driver surface_fan = {
 	.probe = surface_fan_probe,
 	.remove = surface_fan_remove,
+	.match_table = ssam_fan_match,
 	.driver = {
 		.name = "surface_fan",
-		.acpi_match_table = surface_fan_match,
 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
 	},
 };
-
-static int __init surface_fan_init(void)
-{
-	return platform_driver_register(&surface_fan);
-}
-module_init(surface_fan_init);
-
-static void __exit surface_fan_exit(void)
-{
-	platform_driver_unregister(&surface_fan);
-}
-module_exit(surface_fan_exit);
+module_ssam_device_driver(surface_fan);
 
 MODULE_AUTHOR("Ivor Wanders <ivor@iwanders.net>");
 MODULE_DESCRIPTION("Fan Driver for Surface System Aggregator Module");