use apple_brightness to save brightness to EFI.

(tested on iMac20,1)

Signed-off-by: Atharva Tiwari <atharvatiwarilinuxdev@gmail.com>
---
 drivers/platform/x86/apple-gmux.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c
index 1417e230edbd..cab3122c1a86 100644
--- a/drivers/platform/x86/apple-gmux.c
+++ b/drivers/platform/x86/apple-gmux.c
@@ -22,6 +22,7 @@
 #include <linux/pci.h>
 #include <linux/vga_switcheroo.h>
 #include <linux/debugfs.h>
+#include <linux/platform_data/apple-brightness.h>
 #include <acpi/video.h>
 #include <asm/io.h>
 
@@ -78,6 +79,8 @@ struct apple_gmux_data {
 	/* debugfs data */
 	u8 selected_port;
 	struct dentry *debug_dentry;
+
+	bool save_efi;
 };
 
 static struct apple_gmux_data *apple_gmux_data;
@@ -960,6 +963,13 @@ static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
 	}
 
 	gmux_init_debugfs(gmux_data);
+	if (IS_ENABLED(CONFIG_APPLE_BRIGHTNESS)) {
+		ret = apple_brightness_probe(gmux_data->bdev, &gmux_get_brightness);
+		if (ret)
+			pr_warn("Unable to Enable EFI brightness save: %d\n", ret);
+		else
+			gmux_data->save_efi = true;
+	}
 	return 0;
 
 err_register_handler:
@@ -1012,6 +1022,16 @@ static void gmux_remove(struct pnp_dev *pnp)
 	kfree(gmux_data);
 }
 
+static void gmux_shutdown(struct pnp_dev *pnp)
+{
+	struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
+
+	if (IS_ENABLED(CONFIG_APPLE_BRIGHTNESS) && gmux_data->save_efi)
+		apple_brightness_shutdown();
+
+	gmux_remove(pnp);
+}
+
 static const struct pnp_device_id gmux_device_ids[] = {
 	{GMUX_ACPI_HID, 0},
 	{"", 0}
@@ -1026,6 +1046,7 @@ static struct pnp_driver gmux_pnp_driver = {
 	.name		= "apple-gmux",
 	.probe		= gmux_probe,
 	.remove		= gmux_remove,
+	.shutdown	= gmux_shutdown,
 	.id_table	= gmux_device_ids,
 	.driver		= {
 			.pm = &gmux_dev_pm_ops,
-- 
2.43.0