platform/surface: surfacepro3_button: Check ACPI_COMPANION()

Every platform driver can be forced to match a device that doesn't match
its list of device IDs because of device_match_driver_override(), so
platform drivers that rely on the existence of a device's ACPI companion
object need to verify its presence.

Accordingly, add a requisite ACPI_COMPANION() check against NULL to the
surfacepro3_button driver.

Fixes: d913a5a12b40 ("platform/surface: surfacepro3_button: Convert to a platform driver")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Chen Yu <yu.c.chen@intel.com>
Link: https://patch.msgid.link/23119222.EfDdHjke4D@rafael.j.wysocki
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

diff --git a/drivers/platform/surface/surfacepro3_button.c b/drivers/platform/surface/surfacepro3_button.c
index 0293bc517b544ce7c7f4f2fb1c95664c7fa360b6..388a3e1a488cb7372ae6b97f4c43c4daafe313d6 100644 (file)
--- a/drivers/platform/surface/surfacepro3_button.c
+++ b/drivers/platform/surface/surfacepro3_button.c
@@ -185,12 +185,15 @@ static bool surface_button_check_MSHW0040(struct device *dev, acpi_handle handle
 
 static int surface_button_probe(struct platform_device *pdev)
 {
-       struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
        struct surface_button *button;
+       struct acpi_device *device;
        struct input_dev *input;
-       const char *hid = acpi_device_hid(device);
        int error;
 
+       device = ACPI_COMPANION(&pdev->dev);
+       if (!device)
+               return -ENODEV;
+
        if (strncmp(acpi_device_bid(device), SURFACE_BUTTON_OBJ_NAME,
            strlen(SURFACE_BUTTON_OBJ_NAME)))
                return -ENODEV;
@@ -210,7 +213,8 @@ static int surface_button_probe(struct platform_device *pdev)
        }
 
        strscpy(acpi_device_name(device), SURFACE_BUTTON_DEVICE_NAME);
-       snprintf(button->phys, sizeof(button->phys), "%s/buttons", hid);
+       snprintf(button->phys, sizeof(button->phys), "%s/buttons",
+                acpi_device_hid(device));
 
        input->name = acpi_device_name(device);
        input->phys = button->phys;