[PATCH v4 2/2] platform/apple-gmux: use apple_brightness to save brightness to EFI

Atharva Tiwari
2026-03-16T15:34:32Z

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