From: James Calligeros <jcalligeros99@gmail.com>
To: Sven Peter <sven@kernel.org>, Janne Grunau <j@jannau.net>,
Alyssa Rosenzweig <alyssa@rosenzweig.io>,
Neal Gompa <neal@gompa.dev>,  Lee Jones <lee@kernel.org>,
Rob Herring <robh@kernel.org>,
Krzysztof Kozlowski <krzk+dt@kernel.org>,
Conor Dooley <conor+dt@kernel.org>,
Alexandre Belloni <alexandre.belloni@bootlin.com>,
Jean Delvare <jdelvare@suse.com>,
Guenter Roeck <linux@roeck-us.net>,
Dmitry Torokhov <dmitry.torokhov@gmail.com>,
Jonathan Corbet <corbet@lwn.net>,
James Calligeros <jcalligeros99@gmail.com>
Cc: asahi@lists.linux.dev, linux-arm-kernel@lists.infradead.org,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-rtc@vger.kernel.org, linux-hwmon@vger.kernel.org,
linux-input@vger.kernel.org, linux-doc@vger.kernel.org,
Hector Martin <marcan@marcan.st>
Subject: [PATCH v6 4/7] input: macsmc-input: New driver to handle the Apple Mac SMC buttons/lid
Date: Mon, 15 Dec 2025 19:37:48 +1000	[thread overview]
Message-ID: <20251215-macsmc-subdevs-v6-4-0518cb5f28ae@gmail.com> (raw)
In-Reply-To: <20251215-macsmc-subdevs-v6-0-0518cb5f28ae@gmail.com>

From: Hector Martin <marcan@marcan.st>

This driver implements power button and lid switch support for Apple Mac
devices using SMC controllers driven by the macsmc driver.

In addition to basic input support, this also responds to the final
shutdown warning (when the power button is held down long enough) by
doing an emergency kernel poweroff. This allows the NVMe controller to
be cleanly shut down, which prevents data loss for in-cache data.

Reviewed-by: Neal Gompa <neal@gompa.dev>
Signed-off-by: Hector Martin <marcan@marcan.st>
Co-developed-by: Sven Peter <sven@kernel.org>
Signed-off-by: Sven Peter <sven@kernel.org>
Signed-off-by: James Calligeros <jcalligeros99@gmail.com>
---
MAINTAINERS                       |   1 +
drivers/input/misc/Kconfig        |  11 ++
drivers/input/misc/Makefile       |   1 +
drivers/input/misc/macsmc-input.c | 207 +++++++++++++++++++++++++
4 files changed, 220 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 5f160eb6762e..7f2160a18da2 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2492,6 +2492,7 @@ F:	drivers/hwmon/macsmc-hwmon.c
F:	drivers/pmdomain/apple/
F:	drivers/i2c/busses/i2c-pasemi-core.c
F:	drivers/i2c/busses/i2c-pasemi-platform.c
+F:	drivers/input/misc/macsmc-input.c
F:	drivers/input/touchscreen/apple_z2.c
F:	drivers/iommu/apple-dart.c
F:	drivers/iommu/io-pgtable-dart.c
diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
index 94a753fcb64f..0e805c870e29 100644
--- a/drivers/input/misc/Kconfig
+++ b/drivers/input/misc/Kconfig
@@ -1003,4 +1003,15 @@ config INPUT_STPMIC1_ONKEY
To compile this driver as a module, choose M here: the
module will be called stpmic1_onkey.

+config INPUT_MACSMC
+	tristate "Apple Mac SMC lid/buttons"
+	depends on MFD_MACSMC
+	help
+	  Say Y here if you want to use the input events delivered via the
+	  SMC controller on Apple Mac machines using the macsmc driver.
+	  This includes lid open/close and the power button.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called macsmc-input.
+
endif
diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile
index 415fc4e2918b..174031304975 100644
--- a/drivers/input/misc/Makefile
+++ b/drivers/input/misc/Makefile
@@ -52,6 +52,7 @@ obj-$(CONFIG_INPUT_IQS7222)		+= iqs7222.o
obj-$(CONFIG_INPUT_KEYSPAN_REMOTE)	+= keyspan_remote.o
obj-$(CONFIG_INPUT_KXTJ9)		+= kxtj9.o
obj-$(CONFIG_INPUT_M68K_BEEP)		+= m68kspkr.o
+obj-$(CONFIG_INPUT_MACSMC_INPUT)	+= macsmc-input.o
obj-$(CONFIG_INPUT_MAX7360_ROTARY)	+= max7360-rotary.o
obj-$(CONFIG_INPUT_MAX77650_ONKEY)	+= max77650-onkey.o
obj-$(CONFIG_INPUT_MAX77693_HAPTIC)	+= max77693-haptic.o
diff --git a/drivers/input/misc/macsmc-input.c b/drivers/input/misc/macsmc-input.c
new file mode 100644
index 000000000000..f4598e65fc80
--- /dev/null
+++ b/drivers/input/misc/macsmc-input.c
@@ -0,0 +1,207 @@
+// SPDX-License-Identifier: GPL-2.0-only OR MIT
+/*
+ * Apple SMC input event driver
+ * Copyright The Asahi Linux Contributors
+ *
+ * This driver exposes certain events from the SMC as an input device.
+ * This includes the lid open/close and power button notifications.
+ */
+
+#include <linux/device.h>
+#include <linux/input.h>
+#include <linux/mfd/macsmc.h>
+#include <linux/module.h>
+#include <linux/reboot.h>
+
+/**
+ * struct macsmc_input
+ * @dev: Underlying struct device for the input sub-device
+ * @smc: Pointer to apple_smc struct of the mfd parent
+ * @input: Allocated input_dev; devres managed
+ * @nb: Notifier block used for incoming events from SMC (e.g. button pressed down)
+ * @wakeup_mode: Set to true when system is suspended and power button events should wake it
+ */
+struct macsmc_input {
+	struct device *dev;
+	struct apple_smc *smc;
+	struct input_dev *input;
+	struct notifier_block nb;
+	bool wakeup_mode;
+};
+
+#define SMC_EV_BTN 0x7201
+#define SMC_EV_LID 0x7203
+
+#define BTN_POWER		0x01 /* power button on e.g. Mac Mini chasis pressed */
+#define BTN_TOUCHID		0x06 /* combined TouchID / power button on MacBooks pressed */
+#define BTN_POWER_HELD_SHORT	0xfe /* power button briefly held down */
+#define BTN_POWER_HELD_LONG	0x00 /* power button held down; sent just before forced poweroff */
+
+static void macsmc_input_event_button(struct macsmc_input *smcin, unsigned long event)
+{
+	u8 button = (event >> 8) & 0xff;
+	u8 state = !!(event & 0xff);
+
+	switch (button) {
+	case BTN_POWER:
+	case BTN_TOUCHID:
+		pm_wakeup_dev_event(smcin->dev, 0, (smcin->wakeup_mode && state));
+
+		/* Suppress KEY_POWER event to prevent immediate shutdown on wake */
+		if (smcin->wakeup_mode)
+			return;
+
+		input_report_key(smcin->input, KEY_POWER, state);
+		input_sync(smcin->input);
+		break;
+	case BTN_POWER_HELD_SHORT: /* power button held down; ignore */
+		break;
+	case BTN_POWER_HELD_LONG:
+		/*
+		 * If we get here the power button has been held down for a while and
+		 * we have about 4 seconds before forced power-off is triggered by SMC.
+		 * Try to do an emergency shutdown to make sure the NVMe cache is
+		 * flushed. macOS actually does this by panicing (!)...
+		 */
+		if (state) {
+			dev_crit(smcin->dev, "Triggering forced shutdown!\n");
+			if (kernel_can_power_off())
+				kernel_power_off();
+			else /* Missing macsmc-reboot driver? */
+				kernel_restart("SMC power button triggered restart");
+		}
+		break;
+	default:
+		dev_warn(smcin->dev, "Unknown SMC button event: %04lx\n", event & 0xffff);
+	}
+}
+
+static void macsmc_input_event_lid(struct macsmc_input *smcin, unsigned long event)
+{
+	u8 lid_state = !!((event >> 8) & 0xff);
+
+	pm_wakeup_dev_event(smcin->dev, 0, (smcin->wakeup_mode && !lid_state));
+	input_report_switch(smcin->input, SW_LID, lid_state);
+	input_sync(smcin->input);
+}
+
+static int macsmc_input_event(struct notifier_block *nb, unsigned long event, void *data)
+{
+	struct macsmc_input *smcin = container_of(nb, struct macsmc_input, nb);
+	u16 type = event >> 16;
+
+	switch (type) {
+	case SMC_EV_BTN:
+		macsmc_input_event_button(smcin, event);
+		return NOTIFY_OK;
+	case SMC_EV_LID:
+		macsmc_input_event_lid(smcin, event);
+		return NOTIFY_OK;
+	default:
+		/* SMC event meant for another driver */
+		return NOTIFY_DONE;
+	}
+}
+
+static int macsmc_input_probe(struct platform_device *pdev)
+{
+	struct apple_smc *smc = dev_get_drvdata(pdev->dev.parent);
+	struct macsmc_input *smcin;
+	bool have_lid, have_power;
+	int error;
+
+	/* Bail early if this SMC neither supports power button nor lid events */
+	have_lid = apple_smc_key_exists(smc, SMC_KEY(MSLD));
+	have_power = apple_smc_key_exists(smc, SMC_KEY(bHLD));
+	if (!have_lid && !have_power)
+		return -ENODEV;
+
+	smcin = devm_kzalloc(&pdev->dev, sizeof(*smcin), GFP_KERNEL);
+	if (!smcin)
+		return -ENOMEM;
+
+	smcin->dev = &pdev->dev;
+	smcin->smc = smc;
+	platform_set_drvdata(pdev, smcin);
+
+	smcin->input = devm_input_allocate_device(&pdev->dev);
+	if (!smcin->input)
+		return -ENOMEM;
+
+	smcin->input->phys = "macsmc-input (0)";
+	smcin->input->name = "Apple SMC power/lid events";
+
+	if (have_lid)
+		input_set_capability(smcin->input, EV_SW, SW_LID);
+	if (have_power)
+		input_set_capability(smcin->input, EV_KEY, KEY_POWER);
+
+	if (have_lid) {
+		u8 val;
+
+		error = apple_smc_read_u8(smc, SMC_KEY(MSLD), &val);
+		if (error < 0)
+			dev_warn(&pdev->dev, "Failed to read initial lid state\n");
+		else
+			input_report_switch(smcin->input, SW_LID, val);
+	}
+
+	if (have_power) {
+		u32 val;
+
+		error = apple_smc_read_u32(smc, SMC_KEY(bHLD), &val);
+		if (error < 0)
+			dev_warn(&pdev->dev, "Failed to read initial power button state\n");
+		else
+			input_report_key(smcin->input, KEY_POWER, val & 1);
+	}
+
+	error = input_register_device(smcin->input);
+	if (error) {
+		dev_err(&pdev->dev, "Failed to register input device: %d\n", error);
+		return error;
+	}
+
+	input_sync(smcin->input);
+
+	smcin->nb.notifier_call = macsmc_input_event;
+	blocking_notifier_chain_register(&smc->event_handlers, &smcin->nb);
+
+	device_init_wakeup(&pdev->dev, true);
+
+	return 0;
+}
+
+static int macsmc_input_pm_prepare(struct device *dev)
+{
+	struct macsmc_input *smcin = dev_get_drvdata(dev);
+
+	smcin->wakeup_mode = true;
+	return 0;
+}
+
+static void macsmc_input_pm_complete(struct device *dev)
+{
+	struct macsmc_input *smcin = dev_get_drvdata(dev);
+
+	smcin->wakeup_mode = false;
+}
+
+static const struct dev_pm_ops macsmc_input_pm_ops = {
+	.prepare = macsmc_input_pm_prepare,
+	.complete = macsmc_input_pm_complete,
+};
+
+static struct platform_driver macsmc_input_driver = {
+	.driver = {
+		.name = "macsmc-input",
+		.pm = &macsmc_input_pm_ops,
+	},
+	.probe = macsmc_input_probe,
+};
+module_platform_driver(macsmc_input_driver);
+
+MODULE_AUTHOR("Hector Martin <marcan@marcan.st>");
+MODULE_LICENSE("Dual MIT/GPL");
+MODULE_DESCRIPTION("Apple SMC input driver");
+MODULE_ALIAS("platform:macsmc-input");

--
2.52.0

next prev parent reply	other threads:[~2025-12-15  9:38 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-12-15  9:37 [PATCH v6 0/7] mfd: macsmc: add rtc, hwmon and hid subdevices James Calligeros
2025-12-15  9:37 ` [PATCH v6 1/7] dt-bindings: hwmon: Add Apple System Management Controller hwmon schema James Calligeros
2025-12-15 10:36   ` Rob Herring (Arm)
2025-12-15  9:37 ` [PATCH v6 2/7] mfd: macsmc: Wire up Apple SMC RTC subdevice James Calligeros
2025-12-15  9:37 ` [PATCH v6 3/7] mfd: macsmc: Wire up Apple SMC hwmon subdevice James Calligeros
2025-12-15  9:37 ` James Calligeros [this message]
2025-12-15  9:37 ` [PATCH v6 5/7] mfd: macsmc: Wire up Apple SMC input subdevice James Calligeros
2025-12-15  9:37 ` [PATCH v6 6/7] arm64: dts: apple: t8103,t60xx,t8112: Add SMC RTC node James Calligeros
2025-12-15  9:37 ` [PATCH v6 7/7] arm64: dts: apple: t8103, t8112, t60xx: Add hwmon SMC subdevice James Calligeros
2025-12-16 12:37 ` (subset) [PATCH v6 0/7] mfd: macsmc: add rtc, hwmon and hid subdevices Sven Peter

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