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..3797a0e7ff40 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 (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

Hi Atharva,

kernel test robot noticed the following build errors:

[auto build test ERROR on efi/next]
[also build test ERROR on linus/master v7.0-rc4 next-20260313]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Atharva-Tiwari/efi-Save-Brightness-using-EFI-on-Macs/20260316-084441
base:   https://git.kernel.org/pub/scm/linux/kernel/git/efi/efi.git next
patch link:    https://lore.kernel.org/r/20260315222020.24341-3-atharvatiwarilinuxdev%40gmail.com
patch subject: [PATCH v3 2/2] platform/apple-gmux: use apple_brightness to save brightness to EFI
config: x86_64-rhel-9.4 (https://download.01.org/0day-ci/archive/20260316/202603161105.ILZkpASC-lkp@intel.com/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260316/202603161105.ILZkpASC-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202603161105.ILZkpASC-lkp@intel.com/

All errors (new ones prefixed by >>, old ones prefixed by <<):

>> ERROR: modpost: "apple_brightness_shutdown" [drivers/platform/x86/apple-gmux.ko] undefined!

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki