platform/x86: Add intel_skl_int3472 driver

ACPI devices with _HID INT3472 are currently matched to the tps68470
driver, however this does not cover all situations in which that _HID
occurs. We've encountered three possibilities:

1. On Chrome OS devices, an ACPI device with _HID INT3472 (representing
a physical TPS68470 device) that requires a GPIO and OpRegion driver
2. On devices designed for Windows, an ACPI device with _HID INT3472
(again representing a physical TPS68470 device) which requires GPIO,
Clock and Regulator drivers.
3. On other devices designed for Windows, an ACPI device with _HID
INT3472 which does **not** represent a physical TPS68470, and is instead
used as a dummy device to group some system GPIO lines which are meant
to be consumed by the sensor that is dependent on this entry.

This commit adds a new module, registering a platform driver to deal
with the 3rd scenario plus an i2c driver to deal with #1 and #2, by
querying the CLDB buffer found against INT3472 entries to determine
which is most appropriate.

Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Daniel Scally <djrscally@gmail.com>
Link: https://lore.kernel.org/r/20210603224007.120560-6-djrscally@gmail.com


[hdegoede@redhat.com Make skl_int3472_tps68470_calc_type() static]
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

MAINTAINERS

@@ -9385,6 +9385,11 @@ S:	Maintained
 F:	arch/x86/include/asm/intel_scu_ipc.h
 F:	drivers/platform/x86/intel_scu_*
+INTEL SKYLAKE INT3472 ACPI DEVICE DRIVER
+M:	Daniel Scally <djrscally@gmail.com>
+S:	Maintained
+F:	drivers/platform/x86/intel-int3472/
+
 INTEL SPEED SELECT TECHNOLOGY
 M:	Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
 L:	platform-driver-x86@vger.kernel.org

drivers/platform/x86/Kconfig

@@ -709,6 +709,8 @@ config INTEL_CHT_INT33FE
 	  device and CONFIG_TYPEC_FUSB302=m and CONFIG_BATTERY_MAX17042=m
 	  for Type-C device.
 
+source "drivers/platform/x86/intel-int3472/Kconfig"
+
 config INTEL_HID_EVENT
 	tristate "INTEL HID Event"
 	depends on ACPI

drivers/platform/x86/Makefile

@@ -76,6 +76,7 @@ obj-$(CONFIG_INTEL_HID_EVENT)		+= intel-hid.o
 obj-$(CONFIG_INTEL_INT0002_VGPIO)	+= intel_int0002_vgpio.o
 obj-$(CONFIG_INTEL_MENLOW)		+= intel_menlow.o
 obj-$(CONFIG_INTEL_OAKTRAIL)		+= intel_oaktrail.o
+obj-$(CONFIG_INTEL_SKL_INT3472)		+= intel-int3472/
 obj-$(CONFIG_INTEL_VBTN)		+= intel-vbtn.o
 
 # MSI

drivers/platform/x86/intel-int3472/Kconfig

+config INTEL_SKL_INT3472
+	tristate "Intel SkyLake ACPI INT3472 Driver"
+	depends on ACPI
+	depends on COMMON_CLK && CLKDEV_LOOKUP
+	depends on I2C
+	depends on GPIOLIB
+	depends on REGULATOR
+	select MFD_CORE
+	select REGMAP_I2C
+	help
+	  This driver adds power controller support for the Intel SkyCam
+	  devices found on the Intel SkyLake platforms.
+
+	  The INT3472 is a camera power controller, a logical device found on
+	  Intel Skylake-based systems that can map to different hardware
+	  devices depending on the platform. On machines designed for Chrome OS
+	  it maps to a TPS68470 camera PMIC. On machines designed for Windows,
+	  it maps to either a TP68470 camera PMIC, a uP6641Q sensor PMIC, or a
+	  set of discrete GPIOs and power gates.
+
+	  If your device was designed for Chrome OS, this driver will provide
+	  an ACPI OpRegion, which must be available before any of the devices
+	  using it are probed. For this reason, you should select Y if your
+	  device was designed for ChromeOS. For the same reason the
+	  I2C_DESIGNWARE_PLATFORM option must be set to Y too.
+
+	  Say Y or M here if you have a SkyLake device designed for use
+	  with Windows or ChromeOS. Say N here if you are not sure.
+
+	  The module will be named "intel-skl-int3472".

drivers/platform/x86/intel-int3472/Makefile

+obj-$(CONFIG_INTEL_SKL_INT3472)		+= intel_skl_int3472.o
+intel_skl_int3472-objs			:= intel_skl_int3472_common.o \
+					   intel_skl_int3472_discrete.o \
+					   intel_skl_int3472_tps68470.o \
+					   intel_skl_int3472_clk_and_regulator.o

drivers/platform/x86/intel-int3472/intel_skl_int3472_clk_and_regulator.c

+// SPDX-License-Identifier: GPL-2.0
+/* Author: Dan Scally <djrscally@gmail.com> */
+
+#include <linux/acpi.h>
+#include <linux/clkdev.h>
+#include <linux/clk-provider.h>
+#include <linux/device.h>
+#include <linux/gpio/consumer.h>
+#include <linux/regulator/driver.h>
+#include <linux/slab.h>
+
+#include "intel_skl_int3472_common.h"
+
+/*
+ * The regulators have to have .ops to be valid, but the only ops we actually
+ * support are .enable and .disable which are handled via .ena_gpiod. Pass an
+ * empty struct to clear the check without lying about capabilities.
+ */
+static const struct regulator_ops int3472_gpio_regulator_ops;
+
+static int skl_int3472_clk_prepare(struct clk_hw *hw)
+{
+	struct int3472_gpio_clock *clk = to_int3472_clk(hw);
+
+	gpiod_set_value_cansleep(clk->ena_gpio, 1);
+	gpiod_set_value_cansleep(clk->led_gpio, 1);
+
+	return 0;
+}
+
+static void skl_int3472_clk_unprepare(struct clk_hw *hw)
+{
+	struct int3472_gpio_clock *clk = to_int3472_clk(hw);
+
+	gpiod_set_value_cansleep(clk->ena_gpio, 0);
+	gpiod_set_value_cansleep(clk->led_gpio, 0);
+}
+
+static int skl_int3472_clk_enable(struct clk_hw *hw)
+{
+	/*
+	 * We're just turning a GPIO on to enable the clock, which operation
+	 * has the potential to sleep. Given .enable() cannot sleep, but
+	 * .prepare() can, we toggle the GPIO in .prepare() instead. Thus,
+	 * nothing to do here.
+	 */
+	return 0;
+}
+
+static void skl_int3472_clk_disable(struct clk_hw *hw)
+{
+	/* Likewise, nothing to do here... */
+}
+
+static unsigned int skl_int3472_get_clk_frequency(struct int3472_discrete_device *int3472)
+{
+	union acpi_object *obj;
+	unsigned int freq;
+
+	obj = skl_int3472_get_acpi_buffer(int3472->sensor, "SSDB");
+	if (IS_ERR(obj))
+		return 0; /* report rate as 0 on error */
+
+	if (obj->buffer.length < CIO2_SENSOR_SSDB_MCLKSPEED_OFFSET + sizeof(u32)) {
+		dev_err(int3472->dev, "The buffer is too small\n");
+		kfree(obj);
+		return 0;
+	}
+
+	freq = *(u32 *)(obj->buffer.pointer + CIO2_SENSOR_SSDB_MCLKSPEED_OFFSET);
+
+	kfree(obj);
+	return freq;
+}
+
+static unsigned long skl_int3472_clk_recalc_rate(struct clk_hw *hw,
+						 unsigned long parent_rate)
+{
+	struct int3472_gpio_clock *clk = to_int3472_clk(hw);
+
+	return clk->frequency;
+}
+
+static const struct clk_ops skl_int3472_clock_ops = {
+	.prepare = skl_int3472_clk_prepare,
+	.unprepare = skl_int3472_clk_unprepare,
+	.enable = skl_int3472_clk_enable,
+	.disable = skl_int3472_clk_disable,
+	.recalc_rate = skl_int3472_clk_recalc_rate,
+};
+
+int skl_int3472_register_clock(struct int3472_discrete_device *int3472)
+{
+	struct clk_init_data init = {
+		.ops = &skl_int3472_clock_ops,
+		.flags = CLK_GET_RATE_NOCACHE,
+	};
+	int ret;
+
+	init.name = kasprintf(GFP_KERNEL, "%s-clk",
+			      acpi_dev_name(int3472->adev));
+	if (!init.name)
+		return -ENOMEM;
+
+	int3472->clock.frequency = skl_int3472_get_clk_frequency(int3472);
+
+	int3472->clock.clk_hw.init = &init;
+	int3472->clock.clk = clk_register(&int3472->adev->dev,
+					  &int3472->clock.clk_hw);
+	if (IS_ERR(int3472->clock.clk)) {
+		ret = PTR_ERR(int3472->clock.clk);
+		goto out_free_init_name;
+	}
+
+	int3472->clock.cl = clkdev_create(int3472->clock.clk, NULL,
+					  int3472->sensor_name);
+	if (!int3472->clock.cl) {
+		ret = -ENOMEM;
+		goto err_unregister_clk;
+	}
+
+	kfree(init.name);
+	return 0;
+
+err_unregister_clk:
+	clk_unregister(int3472->clock.clk);
+out_free_init_name:
+	kfree(init.name);
+
+	return ret;
+}
+
+int skl_int3472_register_regulator(struct int3472_discrete_device *int3472,
+				   struct acpi_resource *ares)
+{
+	char *path = ares->data.gpio.resource_source.string_ptr;
+	const struct int3472_sensor_config *sensor_config;
+	struct regulator_consumer_supply supply_map;
+	struct regulator_init_data init_data = { };
+	struct regulator_config cfg = { };
+	int ret;
+
+	sensor_config = int3472->sensor_config;
+	if (IS_ERR(sensor_config)) {
+		dev_err(int3472->dev, "No sensor module config\n");
+		return PTR_ERR(sensor_config);
+	}
+
+	if (!sensor_config->supply_map.supply) {
+		dev_err(int3472->dev, "No supply name defined\n");
+		return -ENODEV;
+	}
+
+	init_data.constraints.valid_ops_mask = REGULATOR_CHANGE_STATUS;
+	init_data.num_consumer_supplies = 1;
+	supply_map = sensor_config->supply_map;
+	supply_map.dev_name = int3472->sensor_name;
+	init_data.consumer_supplies = &supply_map;
+
+	snprintf(int3472->regulator.regulator_name,
+		 sizeof(int3472->regulator.regulator_name), "%s-regulator",
+		 acpi_dev_name(int3472->adev));
+	snprintf(int3472->regulator.supply_name,
+		 GPIO_REGULATOR_SUPPLY_NAME_LENGTH, "supply-0");
+
+	int3472->regulator.rdesc = INT3472_REGULATOR(
+						int3472->regulator.regulator_name,
+						int3472->regulator.supply_name,
+						&int3472_gpio_regulator_ops);
+
+	int3472->regulator.gpio = acpi_get_and_request_gpiod(path,
+							     ares->data.gpio.pin_table[0],
+							     "int3472,regulator");
+	if (IS_ERR(int3472->regulator.gpio)) {
+		dev_err(int3472->dev, "Failed to get regulator GPIO line\n");
+		return PTR_ERR(int3472->regulator.gpio);
+	}
+
+	cfg.dev = &int3472->adev->dev;
+	cfg.init_data = &init_data;
+	cfg.ena_gpiod = int3472->regulator.gpio;
+
+	int3472->regulator.rdev = regulator_register(&int3472->regulator.rdesc,
+						     &cfg);
+	if (IS_ERR(int3472->regulator.rdev)) {
+		ret = PTR_ERR(int3472->regulator.rdev);
+		goto err_free_gpio;
+	}
+
+	return 0;
+
+err_free_gpio:
+	gpiod_put(int3472->regulator.gpio);
+
+	return ret;
+}

drivers/platform/x86/intel-int3472/intel_skl_int3472_common.c

+// SPDX-License-Identifier: GPL-2.0
+/* Author: Dan Scally <djrscally@gmail.com> */
+
+#include <linux/acpi.h>
+#include <linux/i2c.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#include "intel_skl_int3472_common.h"
+
+union acpi_object *skl_int3472_get_acpi_buffer(struct acpi_device *adev, char *id)
+{
+	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+	acpi_handle handle = adev->handle;
+	union acpi_object *obj;
+	acpi_status status;
+
+	status = acpi_evaluate_object(handle, id, NULL, &buffer);
+	if (ACPI_FAILURE(status))
+		return ERR_PTR(-ENODEV);
+
+	obj = buffer.pointer;
+	if (!obj)
+		return ERR_PTR(-ENODEV);
+
+	if (obj->type != ACPI_TYPE_BUFFER) {
+		acpi_handle_err(handle, "%s object is not an ACPI buffer\n", id);
+		kfree(obj);
+		return ERR_PTR(-EINVAL);
+	}
+
+	return obj;
+}
+
+int skl_int3472_fill_cldb(struct acpi_device *adev, struct int3472_cldb *cldb)
+{
+	union acpi_object *obj;
+	int ret;
+
+	obj = skl_int3472_get_acpi_buffer(adev, "CLDB");
+	if (IS_ERR(obj))
+		return PTR_ERR(obj);
+
+	if (obj->buffer.length > sizeof(*cldb)) {
+		acpi_handle_err(adev->handle, "The CLDB buffer is too large\n");
+		ret = -EINVAL;
+		goto out_free_obj;
+	}
+
+	memcpy(cldb, obj->buffer.pointer, obj->buffer.length);
+	ret = 0;
+
+out_free_obj:
+	kfree(obj);
+	return ret;
+}
+
+static const struct acpi_device_id int3472_device_id[] = {
+	{ "INT3472", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, int3472_device_id);
+
+static struct platform_driver int3472_discrete = {
+	.driver = {
+		.name = "int3472-discrete",
+		.acpi_match_table = int3472_device_id,
+	},
+	.probe = skl_int3472_discrete_probe,
+	.remove = skl_int3472_discrete_remove,
+};
+
+static struct i2c_driver int3472_tps68470 = {
+	.driver = {
+		.name = "int3472-tps68470",
+		.acpi_match_table = int3472_device_id,
+	},
+	.probe_new = skl_int3472_tps68470_probe,
+};
+
+static int skl_int3472_init(void)
+{
+	int ret;
+
+	ret = platform_driver_register(&int3472_discrete);
+	if (ret)
+		return ret;
+
+	ret = i2c_register_driver(THIS_MODULE, &int3472_tps68470);
+	if (ret)
+		platform_driver_unregister(&int3472_discrete);
+
+	return ret;
+}
+module_init(skl_int3472_init);
+
+static void skl_int3472_exit(void)
+{
+	platform_driver_unregister(&int3472_discrete);
+	i2c_del_driver(&int3472_tps68470);
+}
+module_exit(skl_int3472_exit);
+
+MODULE_DESCRIPTION("Intel SkyLake INT3472 ACPI Device Driver");
+MODULE_AUTHOR("Daniel Scally <djrscally@gmail.com>");
+MODULE_LICENSE("GPL v2");

drivers/platform/x86/intel-int3472/intel_skl_int3472_common.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/* Author: Dan Scally <djrscally@gmail.com> */
+
+#ifndef _INTEL_SKL_INT3472_H
+#define _INTEL_SKL_INT3472_H
+
+#include <linux/clk-provider.h>
+#include <linux/gpio/machine.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+#include <linux/types.h>
+
+/* FIXME drop this once the I2C_DEV_NAME_FORMAT macro has been added to include/linux/i2c.h */
+#ifndef I2C_DEV_NAME_FORMAT
+#define I2C_DEV_NAME_FORMAT					"i2c-%s"
+#endif
+
+/* PMIC GPIO Types */
+#define INT3472_GPIO_TYPE_RESET					0x00
+#define INT3472_GPIO_TYPE_POWERDOWN				0x01
+#define INT3472_GPIO_TYPE_POWER_ENABLE				0x0b
+#define INT3472_GPIO_TYPE_CLK_ENABLE				0x0c
+#define INT3472_GPIO_TYPE_PRIVACY_LED				0x0d
+
+#define INT3472_PDEV_MAX_NAME_LEN				23
+#define INT3472_MAX_SENSOR_GPIOS				3
+
+#define GPIO_REGULATOR_NAME_LENGTH				21
+#define GPIO_REGULATOR_SUPPLY_NAME_LENGTH			9
+
+#define CIO2_SENSOR_SSDB_MCLKSPEED_OFFSET			86
+
+#define INT3472_REGULATOR(_name, _supply, _ops)			\
+	(const struct regulator_desc) {				\
+		.name = _name,					\
+		.supply_name = _supply,				\
+		.type = REGULATOR_VOLTAGE,			\
+		.ops = _ops,					\
+		.owner = THIS_MODULE,				\
+	}
+
+#define to_int3472_clk(hw)					\
+	container_of(hw, struct int3472_gpio_clock, clk_hw)
+
+#define to_int3472_device(clk)					\
+	container_of(clk, struct int3472_discrete_device, clock)
+
+struct acpi_device;
+struct i2c_client;
+struct platform_device;
+
+struct int3472_cldb {
+	u8 version;
+	/*
+	 * control logic type
+	 * 0: UNKNOWN
+	 * 1: DISCRETE(CRD-D)
+	 * 2: PMIC TPS68470
+	 * 3: PMIC uP6641
+	 */
+	u8 control_logic_type;
+	u8 control_logic_id;
+	u8 sensor_card_sku;
+	u8 reserved[28];
+};
+
+struct int3472_gpio_function_remap {
+	const char *documented;
+	const char *actual;
+};
+
+struct int3472_sensor_config {
+	const char *sensor_module_name;
+	struct regulator_consumer_supply supply_map;
+	const struct int3472_gpio_function_remap *function_maps;
+};
+
+struct int3472_discrete_device {
+	struct acpi_device *adev;
+	struct device *dev;
+	struct acpi_device *sensor;
+	const char *sensor_name;
+
+	const struct int3472_sensor_config *sensor_config;
+
+	struct int3472_gpio_regulator {
+		char regulator_name[GPIO_REGULATOR_NAME_LENGTH];
+		char supply_name[GPIO_REGULATOR_SUPPLY_NAME_LENGTH];
+		struct gpio_desc *gpio;
+		struct regulator_dev *rdev;
+		struct regulator_desc rdesc;
+	} regulator;
+
+	struct int3472_gpio_clock {
+		struct clk *clk;
+		struct clk_hw clk_hw;
+		struct clk_lookup *cl;
+		struct gpio_desc *ena_gpio;
+		struct gpio_desc *led_gpio;
+		u32 frequency;
+	} clock;
+
+	unsigned int ngpios; /* how many GPIOs have we seen */
+	unsigned int n_sensor_gpios; /* how many have we mapped to sensor */
+	struct gpiod_lookup_table gpios;
+};
+
+int skl_int3472_discrete_probe(struct platform_device *pdev);
+int skl_int3472_discrete_remove(struct platform_device *pdev);
+int skl_int3472_tps68470_probe(struct i2c_client *client);
+union acpi_object *skl_int3472_get_acpi_buffer(struct acpi_device *adev,
+					       char *id);
+int skl_int3472_fill_cldb(struct acpi_device *adev, struct int3472_cldb *cldb);
+int skl_int3472_register_clock(struct int3472_discrete_device *int3472);
+int skl_int3472_register_regulator(struct int3472_discrete_device *int3472,
+				   struct acpi_resource *ares);
+
+#endif

drivers/platform/x86/intel-int3472/intel_skl_int3472_discrete.c

+// SPDX-License-Identifier: GPL-2.0
+/* Author: Dan Scally <djrscally@gmail.com> */
+
+#include <linux/acpi.h>
+#include <linux/clkdev.h>
+#include <linux/clk-provider.h>
+#include <linux/device.h>
+#include <linux/gpio/consumer.h>
+#include <linux/gpio/machine.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/overflow.h>
+#include <linux/platform_device.h>
+#include <linux/uuid.h>
+
+#include "intel_skl_int3472_common.h"
+
+/*
+ * 79234640-9e10-4fea-a5c1-b5aa8b19756f
+ * This _DSM GUID returns information about the GPIO lines mapped to a
+ * discrete INT3472 device. Function number 1 returns a count of the GPIO
+ * lines that are mapped. Subsequent functions return 32 bit ints encoding
+ * information about the GPIO line, including its purpose.
+ */
+static const guid_t int3472_gpio_guid =
+	GUID_INIT(0x79234640, 0x9e10, 0x4fea,
+		  0xa5, 0xc1, 0xb5, 0xaa, 0x8b, 0x19, 0x75, 0x6f);
+
+/*
+ * 822ace8f-2814-4174-a56b-5f029fe079ee
+ * This _DSM GUID returns a string from the sensor device, which acts as a
+ * module identifier.
+ */
+static const guid_t cio2_sensor_module_guid =
+	GUID_INIT(0x822ace8f, 0x2814, 0x4174,
+		  0xa5, 0x6b, 0x5f, 0x02, 0x9f, 0xe0, 0x79, 0xee);
+
+/*
+ * Here follows platform specific mapping information that we can pass to
+ * the functions mapping resources to the sensors. Where the sensors have
+ * a power enable pin defined in DSDT we need to provide a supply name so
+ * the sensor drivers can find the regulator. The device name will be derived
+ * from the sensor's ACPI device within the code. Optionally, we can provide a
+ * NULL terminated array of function name mappings to deal with any platform
+ * specific deviations from the documented behaviour of GPIOs.
+ *
+ * Map a GPIO function name to NULL to prevent the driver from mapping that
+ * GPIO at all.
+ */
+
+static const struct int3472_gpio_function_remap ov2680_gpio_function_remaps[] = {
+	{ "reset", NULL },
+	{ "powerdown", "reset" },
+	{ }
+};
+
+static const struct int3472_sensor_config int3472_sensor_configs[] = {
+	/* Lenovo Miix 510-12ISK - OV2680, Front */
+	{ "GNDF140809R", { 0 }, ov2680_gpio_function_remaps },
+	/* Lenovo Miix 510-12ISK - OV5648, Rear */
+	{ "GEFF150023R", REGULATOR_SUPPLY("avdd", NULL), NULL },
+	/* Surface Go 1&2 - OV5693, Front */
+	{ "YHCU", REGULATOR_SUPPLY("avdd", NULL), NULL },
+};
+
+static const struct int3472_sensor_config *
+skl_int3472_get_sensor_module_config(struct int3472_discrete_device *int3472)
+{
+	union acpi_object *obj;
+	unsigned int i;
+
+	obj = acpi_evaluate_dsm_typed(int3472->sensor->handle,
+				      &cio2_sensor_module_guid, 0x00,
+				      0x01, NULL, ACPI_TYPE_STRING);
+
+	if (!obj) {
+		dev_err(int3472->dev,
+			"Failed to get sensor module string from _DSM\n");
+		return ERR_PTR(-ENODEV);
+	}
+
+	if (obj->string.type != ACPI_TYPE_STRING) {
+		dev_err(int3472->dev,
+			"Sensor _DSM returned a non-string value\n");
+
+		ACPI_FREE(obj);
+		return ERR_PTR(-EINVAL);
+	}
+
+	for (i = 0; i < ARRAY_SIZE(int3472_sensor_configs); i++) {
+		if (!strcmp(int3472_sensor_configs[i].sensor_module_name,
+			    obj->string.pointer))
+			break;
+	}
+
+	ACPI_FREE(obj);
+
+	if (i >= ARRAY_SIZE(int3472_sensor_configs))
+		return ERR_PTR(-EINVAL);
+
+	return &int3472_sensor_configs[i];
+}
+
+static int skl_int3472_map_gpio_to_sensor(struct int3472_discrete_device *int3472,
+					  struct acpi_resource *ares,
+					  const char *func, u32 polarity)
+{
+	char *path = ares->data.gpio.resource_source.string_ptr;
+	const struct int3472_sensor_config *sensor_config;
+	struct gpiod_lookup *table_entry;
+	struct acpi_device *adev;
+	acpi_handle handle;
+	acpi_status status;
+	int ret;
+
+	if (int3472->n_sensor_gpios >= INT3472_MAX_SENSOR_GPIOS) {
+		dev_warn(int3472->dev, "Too many GPIOs mapped\n");
+		return -EINVAL;
+	}
+
+	sensor_config = int3472->sensor_config;
+	if (!IS_ERR(sensor_config) && sensor_config->function_maps) {
+		const struct int3472_gpio_function_remap *remap;
+
+		for (remap = sensor_config->function_maps; remap->documented; remap++) {
+			if (!strcmp(func, remap->documented)) {
+				func = remap->actual;
+				break;
+			}
+		}
+	}
+
+	/* Functions mapped to NULL should not be mapped to the sensor */
+	if (!func)
+		return 0;
+
+	status = acpi_get_handle(NULL, path, &handle);
+	if (ACPI_FAILURE(status))
+		return -EINVAL;
+
+	ret = acpi_bus_get_device(handle, &adev);
+	if (ret)
+		return -ENODEV;
+
+	table_entry = &int3472->gpios.table[int3472->n_sensor_gpios];
+	table_entry->key = acpi_dev_name(adev);
+	table_entry->chip_hwnum = ares->data.gpio.pin_table[0];
+	table_entry->con_id = func;
+	table_entry->idx = 0;
+	table_entry->flags = polarity;
+
+	int3472->n_sensor_gpios++;
+
+	return 0;
+}
+
+static int skl_int3472_map_gpio_to_clk(struct int3472_discrete_device *int3472,
+				       struct acpi_resource *ares, u8 type)
+{
+	char *path = ares->data.gpio.resource_source.string_ptr;
+	struct gpio_desc *gpio;
+
+	switch (type) {
+	case INT3472_GPIO_TYPE_CLK_ENABLE:
+		gpio = acpi_get_and_request_gpiod(path, ares->data.gpio.pin_table[0],
+						  "int3472,clk-enable");
+		if (IS_ERR(gpio))
+			return (PTR_ERR(gpio));
+
+		int3472->clock.ena_gpio = gpio;
+		break;
+	case INT3472_GPIO_TYPE_PRIVACY_LED:
+		gpio = acpi_get_and_request_gpiod(path, ares->data.gpio.pin_table[0],
+						  "int3472,privacy-led");
+		if (IS_ERR(gpio))
+			return (PTR_ERR(gpio));
+
+		int3472->clock.led_gpio = gpio;
+		break;
+	default:
+		dev_err(int3472->dev, "Invalid GPIO type 0x%02x for clock\n", type);
+		break;
+	}
+
+	return 0;
+}
+
+/**
+ * skl_int3472_handle_gpio_resources: Map PMIC resources to consuming sensor
+ * @ares: A pointer to a &struct acpi_resource
+ * @data: A pointer to a &struct int3472_discrete_device
+ *
+ * This function handles GPIO resources that are against an INT3472
+ * ACPI device, by checking the value of the corresponding _DSM entry.
+ * This will return a 32bit int, where the lowest byte represents the
+ * function of the GPIO pin:
+ *
+ * 0x00 Reset
+ * 0x01 Power down
+ * 0x0b Power enable
+ * 0x0c Clock enable
+ * 0x0d Privacy LED
+ *
+ * There are some known platform specific quirks where that does not quite
+ * hold up; for example where a pin with type 0x01 (Power down) is mapped to
+ * a sensor pin that performs a reset function or entries in _CRS and _DSM that
+ * do not actually correspond to a physical connection. These will be handled
+ * by the mapping sub-functions.
+ *
+ * GPIOs will either be mapped directly to the sensor device or else used
+ * to create clocks and regulators via the usual frameworks.
+ *
+ * Return:
+ * * 1		- To continue the loop
+ * * 0		- When all resources found are handled properly.
+ * * -EINVAL	- If the resource is not a GPIO IO resource
+ * * -ENODEV	- If the resource has no corresponding _DSM entry
+ * * -Other	- Errors propagated from one of the sub-functions.
+ */
+static int skl_int3472_handle_gpio_resources(struct acpi_resource *ares,
+					     void *data)
+{
+	struct int3472_discrete_device *int3472 = data;
+	struct acpi_resource_gpio *agpio;
+	union acpi_object *obj;
+	const char *err_msg;
+	int ret;
+	u8 type;
+
+	if (!acpi_gpio_get_io_resource(ares, &agpio))
+		return 1;
+
+	/*
+	 * ngpios + 2 because the index of this _DSM function is 1-based and
+	 * the first function is just a count.
+	 */
+	obj = acpi_evaluate_dsm_typed(int3472->adev->handle,
+				      &int3472_gpio_guid, 0x00,
+				      int3472->ngpios + 2,
+				      NULL, ACPI_TYPE_INTEGER);
+
+	if (!obj) {
+		dev_warn(int3472->dev, "No _DSM entry for GPIO pin %u\n",
+			 ares->data.gpio.pin_table[0]);
+		return 1;
+	}
+
+	type = obj->integer.value & 0xff;
+
+	switch (type) {
+	case INT3472_GPIO_TYPE_RESET:
+		ret = skl_int3472_map_gpio_to_sensor(int3472, ares, "reset",
+						     GPIO_ACTIVE_LOW);
+		if (ret)
+			err_msg = "Failed to map reset pin to sensor\n";
+
+		break;
+	case INT3472_GPIO_TYPE_POWERDOWN:
+		ret = skl_int3472_map_gpio_to_sensor(int3472, ares,
+						     "powerdown",
+						     GPIO_ACTIVE_LOW);
+		if (ret)
+			err_msg = "Failed to map powerdown pin to sensor\n";
+
+		break;
+	case INT3472_GPIO_TYPE_CLK_ENABLE:
+	case INT3472_GPIO_TYPE_PRIVACY_LED:
+		ret = skl_int3472_map_gpio_to_clk(int3472, ares, type);
+		if (ret)
+			err_msg = "Failed to map GPIO to clock\n";
+
+		break;
+	case INT3472_GPIO_TYPE_POWER_ENABLE:
+		ret = skl_int3472_register_regulator(int3472, ares);
+		if (ret)
+			err_msg = "Failed to map regulator to sensor\n";
+
+		break;
+	default:
+		dev_warn(int3472->dev,
+			 "GPIO type 0x%02x unknown; the sensor may not work\n",
+			 type);
+		ret = 1;
+		break;
+	}
+
+	int3472->ngpios++;
+	ACPI_FREE(obj);
+
+	if (ret)
+		return dev_err_probe(int3472->dev, ret, err_msg);
+
+	return 0;
+}
+
+static int skl_int3472_parse_crs(struct int3472_discrete_device *int3472)
+{
+	LIST_HEAD(resource_list);
+	int ret;
+
+	/*
+	 * No error check, because not having a sensor config is not necessarily
+	 * a failure mode.
+	 */
+	int3472->sensor_config = skl_int3472_get_sensor_module_config(int3472);
+
+	ret = acpi_dev_get_resources(int3472->adev, &resource_list,
+				     skl_int3472_handle_gpio_resources,
+				     int3472);
+	if (ret)
+		goto out_free_res_list;
+
+	/*
+	 * If we find no clock enable GPIO pin then the privacy LED won't work.
+	 * We've never seen that situation, but it's possible. Warn the user so
+	 * it's clear what's happened.
+	 */
+	if (int3472->clock.ena_gpio) {
+		ret = skl_int3472_register_clock(int3472);
+		if (ret)
+			goto out_free_res_list;
+	} else {
+		if (int3472->clock.led_gpio)
+			dev_warn(int3472->dev,
+				 "No clk GPIO. The privacy LED won't work\n");
+	}
+
+	int3472->gpios.dev_id = int3472->sensor_name;
+	gpiod_add_lookup_table(&int3472->gpios);
+
+out_free_res_list:
+	acpi_dev_free_resource_list(&resource_list);
+
+	return ret;
+}
+
+int skl_int3472_discrete_probe(struct platform_device *pdev)
+{
+	struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
+	struct int3472_discrete_device *int3472;
+	struct int3472_cldb cldb;
+	int ret;
+
+	ret = skl_int3472_fill_cldb(adev, &cldb);
+	if (ret) {
+		dev_err(&pdev->dev, "Couldn't fill CLDB structure\n");
+		return ret;
+	}
+
+	if (cldb.control_logic_type != 1) {
+		dev_err(&pdev->dev, "Unsupported control logic type %u\n",
+			cldb.control_logic_type);
+		return -EINVAL;
+	}
+
+	/* Max num GPIOs we've seen plus a terminator */
+	int3472 = devm_kzalloc(&pdev->dev, struct_size(int3472, gpios.table,
+			       INT3472_MAX_SENSOR_GPIOS + 1), GFP_KERNEL);
+	if (!int3472)
+		return -ENOMEM;
+
+	int3472->adev = adev;
+	int3472->dev = &pdev->dev;
+	platform_set_drvdata(pdev, int3472);
+
+	int3472->sensor = acpi_dev_get_first_consumer_dev(adev);
+	if (!int3472->sensor) {
+		dev_err(&pdev->dev, "INT3472 seems to have no dependents.\n");
+		return -ENODEV;
+	}
+
+	int3472->sensor_name = devm_kasprintf(int3472->dev, GFP_KERNEL,
+					      I2C_DEV_NAME_FORMAT,
+					      acpi_dev_name(int3472->sensor));
+	if (!int3472->sensor_name) {
+		ret = -ENOMEM;
+		goto err_put_sensor;
+	}
+
+	/*
+	 * Initialising this list means we can call gpiod_remove_lookup_table()
+	 * in failure paths without issue.
+	 */
+	INIT_LIST_HEAD(&int3472->gpios.list);
+
+	ret = skl_int3472_parse_crs(int3472);
+	if (ret) {
+		skl_int3472_discrete_remove(pdev);
+		return ret;
+	}
+
+	return 0;
+
+err_put_sensor:
+	acpi_dev_put(int3472->sensor);
+
+	return ret;
+}
+
+int skl_int3472_discrete_remove(struct platform_device *pdev)
+{
+	struct int3472_discrete_device *int3472 = platform_get_drvdata(pdev);
+
+	gpiod_remove_lookup_table(&int3472->gpios);
+	regulator_unregister(int3472->regulator.rdev);
+	clk_unregister(int3472->clock.clk);
+
+	if (int3472->clock.cl)
+		clkdev_drop(int3472->clock.cl);
+
+	gpiod_put(int3472->regulator.gpio);
+	gpiod_put(int3472->clock.ena_gpio);
+	gpiod_put(int3472->clock.led_gpio);
+
+	return 0;
+}

drivers/platform/x86/intel-int3472/intel_skl_int3472_tps68470.c

+// SPDX-License-Identifier: GPL-2.0
+/* Author: Dan Scally <djrscally@gmail.com> */
+
+#include <linux/i2c.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/tps68470.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#include "intel_skl_int3472_common.h"
+
+#define DESIGNED_FOR_CHROMEOS		1
+#define DESIGNED_FOR_WINDOWS		2
+
+static const struct mfd_cell tps68470_cros[] = {
+	{ .name = "tps68470-gpio" },
+	{ .name = "tps68470_pmic_opregion" },
+};
+
+static const struct mfd_cell tps68470_win[] = {
+	{ .name = "tps68470-gpio" },
+	{ .name = "tps68470-clk" },
+	{ .name = "tps68470-regulator" },
+};
+
+static const struct regmap_config tps68470_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = TPS68470_REG_MAX,
+};
+
+static int tps68470_chip_init(struct device *dev, struct regmap *regmap)
+{
+	unsigned int version;
+	int ret;
+
+	/* Force software reset */
+	ret = regmap_write(regmap, TPS68470_REG_RESET, TPS68470_REG_RESET_MASK);
+	if (ret)
+		return ret;
+
+	ret = regmap_read(regmap, TPS68470_REG_REVID, &version);
+	if (ret) {
+		dev_err(dev, "Failed to read revision register: %d\n", ret);
+		return ret;
+	}
+
+	dev_info(dev, "TPS68470 REVID: 0x%02x\n", version);
+
+	return 0;
+}
+
+/** skl_int3472_tps68470_calc_type: Check what platform a device is designed for
+ * @adev: A pointer to a &struct acpi_device
+ *
+ * Check CLDB buffer against the PMIC's adev. If present, then we check
+ * the value of control_logic_type field and follow one of the
+ * following scenarios:
+ *
+ *	1. No CLDB - likely ACPI tables designed for ChromeOS. We
+ *	create platform devices for the GPIOs and OpRegion drivers.
+ *
+ *	2. CLDB, with control_logic_type = 2 - probably ACPI tables
+ *	made for Windows 2-in-1 platforms. Register pdevs for GPIO,
+ *	Clock and Regulator drivers to bind to.
+ *
+ *	3. Any other value in control_logic_type, we should never have
+ *	gotten to this point; fail probe and return.
+ *
+ * Return:
+ * * 1		Device intended for ChromeOS
+ * * 2		Device intended for Windows
+ * * -EINVAL	Where @adev has an object named CLDB but it does not conform to
+ *		our expectations
+ */
+static int skl_int3472_tps68470_calc_type(struct acpi_device *adev)
+{
+	struct int3472_cldb cldb = { 0 };
+	int ret;
+
+	/*
+	 * A CLDB buffer that exists, but which does not match our expectations
+	 * should trigger an error so we don't blindly continue.
+	 */
+	ret = skl_int3472_fill_cldb(adev, &cldb);
+	if (ret && ret != -ENODEV)
+		return ret;
+
+	if (ret)
+		return DESIGNED_FOR_CHROMEOS;
+
+	if (cldb.control_logic_type != 2)
+		return -EINVAL;
+
+	return DESIGNED_FOR_WINDOWS;
+}
+
+int skl_int3472_tps68470_probe(struct i2c_client *client)
+{
+	struct acpi_device *adev = ACPI_COMPANION(&client->dev);
+	struct regmap *regmap;
+	int device_type;
+	int ret;
+
+	regmap = devm_regmap_init_i2c(client, &tps68470_regmap_config);
+	if (IS_ERR(regmap)) {
+		dev_err(&client->dev, "Failed to create regmap: %ld\n", PTR_ERR(regmap));
+		return PTR_ERR(regmap);
+	}
+
+	i2c_set_clientdata(client, regmap);
+
+	ret = tps68470_chip_init(&client->dev, regmap);
+	if (ret < 0) {
+		dev_err(&client->dev, "TPS68470 init error %d\n", ret);
+		return ret;
+	}
+
+	device_type = skl_int3472_tps68470_calc_type(adev);
+	switch (device_type) {
+	case DESIGNED_FOR_WINDOWS:
+		ret = devm_mfd_add_devices(&client->dev, PLATFORM_DEVID_NONE,
+					   tps68470_win, ARRAY_SIZE(tps68470_win),
+					   NULL, 0, NULL);
+		break;
+	case DESIGNED_FOR_CHROMEOS:
+		ret = devm_mfd_add_devices(&client->dev, PLATFORM_DEVID_NONE,
+					   tps68470_cros, ARRAY_SIZE(tps68470_cros),
+					   NULL, 0, NULL);
+		break;
+	default:
+		dev_err(&client->dev, "Failed to add MFD devices\n");
+		return device_type;
+	}
+
+	return ret;
+}