linux-t2-patches/3004-accel.patch

From 01e20cd5c09aa316734b0a322e7d4635ae93ea93 Mon Sep 17 00:00:00 2001
From: Atharva Tiwari <atharvatiwarilinuxdev@gmail.com>
Date: Fri, 24 Apr 2026 18:19:04 +0530
Subject: [PATCH 04/12] accel

Signed-off-by: Atharva Tiwari <atharvatiwarilinuxdev@gmail.com>
---
 MAINTAINERS                      |   1 +
 drivers/iio/accel/Kconfig        |  10 ++
 drivers/iio/accel/Makefile       |   1 +
 drivers/iio/accel/macsmc-accel.c | 266 +++++++++++++++++++++++++++++++
 drivers/mfd/macsmc-core.c        |   1 +
 5 files changed, 279 insertions(+)
 create mode 100644 drivers/iio/accel/macsmc-accel.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 03917e410dd5..25c8146b17a4 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1940,6 +1940,7 @@ F:	drivers/hwmon/applesmc.c
 MACSMC SUPPORT FOR INTEL MACS
 M:	Atharva Tiwari <atharvatiwarilinuxdev@gmail.com>
 S:	Odd fixes
+F:	drivers/iio/accel/macsmc-accel.c
 F:	drivers/iio/light/macsmc-light.c
 F:	drivers/platform/x86/macsmc-acpi.c
 
diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
index 3d3f8d8673dd..7ac4f265d186 100644
--- a/drivers/iio/accel/Kconfig
+++ b/drivers/iio/accel/Kconfig
@@ -531,6 +531,16 @@ config KXCJK1013
 	  To compile this driver as a module, choose M here: the module will
 	  be called kxcjk-1013.
 
+config MACSMC_ACCEL
+	tristate "Apple SMC Motion Sensor Driver"
+	depends on MACSMC_ACPI
+	help
+	  Say yes here if you want support for Apple Motion Sensors, that uses
+	  the System Management Controller.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called macsmc-accel.
+
 config MC3230
 	tristate "mCube MC3230 Digital Accelerometer Driver"
 	depends on I2C
diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile
index fa440a859283..52fe661dec66 100644
--- a/drivers/iio/accel/Makefile
+++ b/drivers/iio/accel/Makefile
@@ -54,6 +54,7 @@ obj-$(CONFIG_KXSD9)	+= kxsd9.o
 obj-$(CONFIG_KXSD9_SPI)	+= kxsd9-spi.o
 obj-$(CONFIG_KXSD9_I2C)	+= kxsd9-i2c.o
 obj-$(CONFIG_MC3230)	+= mc3230.o
+obj-$(CONFIG_MACSMC_ACCEL)	+= macsmc-accel.o
 
 obj-$(CONFIG_MMA7455)		+= mma7455_core.o
 obj-$(CONFIG_MMA7455_I2C)	+= mma7455_i2c.o
diff --git a/drivers/iio/accel/macsmc-accel.c b/drivers/iio/accel/macsmc-accel.c
new file mode 100644
index 000000000000..48bb7c4d9a8c
--- /dev/null
+++ b/drivers/iio/accel/macsmc-accel.c
@@ -0,0 +1,266 @@
+// SPDX-License-Identifier: GPL-2.0-only OR MIT
+/*
+ * Apple SMC Motion Sensor Driver
+ *
+ * Copyright (C) 2026 Atharva Tiwari <atharvatiwarilinuxdev@gmail.com>
+ */
+
+#include <linux/delay.h>
+#include <linux/iio/iio.h>
+#include <linux/input.h>
+#include <linux/mfd/macsmc.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/byteorder/generic.h>
+
+#define INIT_KEY SMC_KEY(MOCN)
+#define X_KEY	SMC_KEY(MO_X)
+#define Y_KEY	SMC_KEY(MO_Y)
+#define Z_KEY	SMC_KEY(MO_Z)
+
+enum {
+	CALIBRATE = 1,
+};
+
+struct macsmc_accel {
+	struct apple_smc *smc;
+	s16 rest_x, rest_y;
+};
+
+static int macsmc_accel_read(struct macsmc_accel *drv, smc_key key, s16 *p)
+{
+	int ret;
+
+	ret = apple_smc_read_s16(drv->smc, key, p);
+	if (ret < 0)
+		return ret;
+
+	*p = cpu_to_be16(*p);
+	return 0;
+}
+
+static int macsmc_accel_dev_init(struct macsmc_accel *drv)
+{
+	int ret, total;
+	u16 buf;
+
+
+	for (total = 5000; total > 0; total -= 50) {
+		ret = apple_smc_read_u16(drv->smc, INIT_KEY, &buf);
+		if (!ret && buf)
+			return 0;
+
+		buf = 0xE0;
+		apple_smc_write_u16(drv->smc, INIT_KEY, buf);
+		msleep(50);
+	}
+
+	return -ENODEV;
+}
+
+static int macsmc_accel_calibrate(struct macsmc_accel *drv)
+{
+	int ret;
+
+	ret = macsmc_accel_read(drv, X_KEY, &drv->rest_x);
+	if (ret < 0)
+		return ret;
+
+	ret = macsmc_accel_read(drv, Y_KEY, &drv->rest_y);
+	if (ret < 0)
+		return ret;
+
+	drv->rest_x = -drv->rest_x;
+	return 0;
+}
+
+static void macsmc_accel_poll(struct input_dev *idev)
+{
+	struct macsmc_accel *drv = input_get_drvdata(idev);
+	int ret;
+	s16 x, y;
+
+	ret = macsmc_accel_read(drv, X_KEY, &x);
+	if (ret < 0)
+		return;
+
+	ret = macsmc_accel_read(drv, Y_KEY, &y);
+	if (ret < 0)
+		return;
+
+	x = -x;
+	input_report_abs(idev, ABS_X, x - drv->rest_x);
+	input_report_abs(idev, ABS_Y, y - drv->rest_y);
+	input_sync(idev);
+}
+
+static int macsmc_accel_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan,
+		int *val, int *val2, long mask)
+{
+	struct macsmc_accel *drv = iio_priv(indio_dev);
+	int ret;
+	s16 buf;
+
+	if (mask != IIO_CHAN_INFO_RAW)
+		return -EINVAL;
+
+	if (chan->channel == CALIBRATE) {
+		*val = drv->rest_x;
+		*val2 = drv->rest_y;
+		return IIO_VAL_INT_MULTIPLE;
+	}
+
+	switch (chan->channel2) {
+	case IIO_MOD_X:
+		ret = macsmc_accel_read(drv, X_KEY, &buf);
+		if (ret < 0)
+			return ret;
+
+		*val = buf;
+		return IIO_VAL_INT;
+	case IIO_MOD_Y:
+		ret = macsmc_accel_read(drv, Y_KEY, &buf);
+		if (ret < 0)
+			return ret;
+
+		*val = buf;
+		return IIO_VAL_INT;
+	case IIO_MOD_Z:
+		ret = macsmc_accel_read(drv, Z_KEY, &buf);
+		if (ret < 0)
+			return ret;
+
+		*val = buf;
+		return IIO_VAL_INT;
+	}
+	return -EINVAL;
+}
+
+static int macsmc_accel_write_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan,
+		int val, int val2, long mask)
+{
+	struct macsmc_accel *drv = iio_priv(indio_dev);
+
+	if (mask != IIO_CHAN_INFO_RAW || chan->channel != CALIBRATE)
+		return -EINVAL;
+
+	return macsmc_accel_calibrate(drv);
+}
+
+static const struct iio_chan_spec macsmc_accel_channels[] = {
+	{
+		.type = IIO_ACCEL,
+		.modified = 1,
+		.channel2 = IIO_MOD_X,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+	},
+	{
+		.type = IIO_ACCEL,
+		.modified = 1,
+		.channel2 = IIO_MOD_Y,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+	},
+	{
+		.type = IIO_ACCEL,
+		.modified = 1,
+		.channel2 = IIO_MOD_Z,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+	},
+	{
+		.type = IIO_ACCEL,
+		.channel = CALIBRATE,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.output = 1,
+		.indexed = 1,
+	}
+};
+
+static const struct iio_info macsmc_accel_info = {
+	.read_raw = macsmc_accel_read_raw,
+	.write_raw = macsmc_accel_write_raw,
+};
+
+static int macsmc_accel_restore(struct device *dev)
+{
+	struct macsmc_accel *drv = dev_get_drvdata(dev);
+
+	return macsmc_accel_dev_init(drv);
+}
+
+static const struct dev_pm_ops macsmc_accel_pm_ops = {
+	.restore = macsmc_accel_restore,
+};
+
+static int macsmc_accel_probe(struct platform_device *pdev)
+{
+	struct macsmc_accel *drv;
+	struct input_dev *idev;
+	struct iio_dev *indio;
+	int ret;
+
+	indio = devm_iio_device_alloc(&pdev->dev, sizeof(*drv));
+	if (!indio)
+		return -ENOMEM;
+
+	drv = iio_priv(indio);
+	drv->smc = dev_get_drvdata(pdev->dev.parent);
+	if (!drv->smc)
+		return -ENODEV;
+
+	if (!apple_smc_key_exists(drv->smc, INIT_KEY))
+		return -ENODEV;
+
+	ret = macsmc_accel_dev_init(drv);
+	if (ret < 0)
+		return ret;
+
+	ret = macsmc_accel_calibrate(drv);
+	if (ret < 0)
+		return ret;
+
+	indio->info = &macsmc_accel_info;
+	indio->channels = macsmc_accel_channels;
+	indio->num_channels = ARRAY_SIZE(macsmc_accel_channels);
+	indio->name = "macsmc-accel";
+	ret = iio_device_register(indio);
+	if (ret)
+		return ret;
+
+	idev = devm_input_allocate_device(&pdev->dev);
+	if (!idev)
+		return -ENOMEM;
+
+	idev->name = "macsmc-accel";
+	idev->id.bustype = BUS_HOST;
+	input_set_abs_params(idev, ABS_X, -256, 256, 4, 4);
+	input_set_abs_params(idev, ABS_Y, -256, 256, 4, 4);
+	input_set_drvdata(idev, drv);
+
+	ret = input_setup_polling(idev, macsmc_accel_poll);
+	if (ret)
+		return ret;
+
+	input_set_poll_interval(idev, 50);
+
+	ret = input_register_device(idev);
+	if (ret)
+		return ret;
+
+	platform_set_drvdata(pdev, drv);
+
+	return 0;
+}
+
+static struct platform_driver macsmc_accel_driver = {
+	.probe = macsmc_accel_probe,
+	.driver = {
+		.name = "macsmc-accel",
+		.pm = &macsmc_accel_pm_ops,
+	},
+};
+module_platform_driver(macsmc_accel_driver);
+
+MODULE_AUTHOR("Atharva Tiwari <atharvatiwarilinuxdev@gmail.com>");
+MODULE_DESCRIPTION("Apple SMC Motion Sensor Driver");
+MODULE_LICENSE("Dual MIT/GPL");
+MODULE_ALIAS("platform:macsmc-accel");
diff --git a/drivers/mfd/macsmc-core.c b/drivers/mfd/macsmc-core.c
index 814bfb3ae0ec..bcfa77dd8146 100644
--- a/drivers/mfd/macsmc-core.c
+++ b/drivers/mfd/macsmc-core.c
@@ -21,6 +21,7 @@ static const struct mfd_cell apple_smc_devs[] = {
 };
 
 static const struct mfd_cell apple_smc_acpi_devs[] = {
+	MFD_CELL_NAME("macsmc-accel"),
 	MFD_CELL_NAME("macsmc-hwmon"),
 	MFD_CELL_NAME("macsmc-light"),
 	MFD_CELL_NAME("macsmc-power"),
-- 
2.43.0