platform/x86: system76_acpi: Guard System76 EC specific functionality

Certain functionality or its implementation in System76 EC firmware may
be different to the proprietary ODM EC firmware. Introduce a new bool,
`has_open_ec`, to guard our specific logic. Detect the use of this by
looking for a custom ACPI method name used in System76 firmware.

Signed-off-by: Tim Crawford <tcrawford@system76.com>
Link: https://lore.kernel.org/r/20211222185154.4560-1-tcrawford@system76.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

diff --git a/drivers/platform/x86/system76_acpi.c b/drivers/platform/x86/system76_acpi.c
index 8b292ee..7299ad0 100644 (file)
--- a/drivers/platform/x86/system76_acpi.c
+++ b/drivers/platform/x86/system76_acpi.c
@@ -35,6 +35,7 @@ struct system76_data {
        union acpi_object *nfan;
        union acpi_object *ntmp;
        struct input_dev *input;
+       bool has_open_ec;
 };
 
 static const struct acpi_device_id device_ids[] = {
@@ -279,20 +280,12 @@ static struct acpi_battery_hook system76_battery_hook = {
 
 static void system76_battery_init(void)
 {
-       acpi_handle handle;
-
-       handle = ec_get_handle();
-       if (handle && acpi_has_method(handle, "GBCT"))
-               battery_hook_register(&system76_battery_hook);
+       battery_hook_register(&system76_battery_hook);
 }
 
 static void system76_battery_exit(void)
 {
-       acpi_handle handle;
-
-       handle = ec_get_handle();
-       if (handle && acpi_has_method(handle, "GBCT"))
-               battery_hook_unregister(&system76_battery_hook);
+       battery_hook_unregister(&system76_battery_hook);
 }
 
 // Get the airplane mode LED brightness
@@ -673,6 +666,10 @@ static int system76_add(struct acpi_device *acpi_dev)
        acpi_dev->driver_data = data;
        data->acpi_dev = acpi_dev;
 
+       // Some models do not run open EC firmware. Check for an ACPI method
+       // that only exists on open EC to guard functionality specific to it.
+       data->has_open_ec = acpi_has_method(acpi_device_handle(data->acpi_dev), "NFAN");
+
        err = system76_get(data, "INIT");
        if (err)
                return err;
@@ -718,27 +715,31 @@ static int system76_add(struct acpi_device *acpi_dev)
        if (err)
                goto error;
 
-       err = system76_get_object(data, "NFAN", &data->nfan);
-       if (err)
-               goto error;
+       if (data->has_open_ec) {
+               err = system76_get_object(data, "NFAN", &data->nfan);
+               if (err)
+                       goto error;
 
-       err = system76_get_object(data, "NTMP", &data->ntmp);
-       if (err)
-               goto error;
+               err = system76_get_object(data, "NTMP", &data->ntmp);
+               if (err)
+                       goto error;
 
-       data->therm = devm_hwmon_device_register_with_info(&acpi_dev->dev,
-               "system76_acpi", data, &thermal_chip_info, NULL);
-       err = PTR_ERR_OR_ZERO(data->therm);
-       if (err)
-               goto error;
+               data->therm = devm_hwmon_device_register_with_info(&acpi_dev->dev,
+                       "system76_acpi", data, &thermal_chip_info, NULL);
+               err = PTR_ERR_OR_ZERO(data->therm);
+               if (err)
+                       goto error;
 
-       system76_battery_init();
+               system76_battery_init();
+       }
 
        return 0;
 
 error:
-       kfree(data->ntmp);
-       kfree(data->nfan);
+       if (data->has_open_ec) {
+               kfree(data->ntmp);
+               kfree(data->nfan);
+       }
        return err;
 }
 
@@ -749,14 +750,15 @@ static int system76_remove(struct acpi_device *acpi_dev)
 
        data = acpi_driver_data(acpi_dev);
 
-       system76_battery_exit();
+       if (data->has_open_ec) {
+               system76_battery_exit();
+               kfree(data->nfan);
+               kfree(data->ntmp);
+       }
 
        devm_led_classdev_unregister(&acpi_dev->dev, &data->ap_led);
        devm_led_classdev_unregister(&acpi_dev->dev, &data->kb_led);
 
-       kfree(data->nfan);
-       kfree(data->ntmp);
-
        system76_get(data, "FINI");
 
        return 0;