[PATCH v2 6/7] platform: x86: Add intel_skl_int3472 driver

[Daniel Scally]

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@xxxxxxxxxxxxxxxx>
Signed-off-by: Daniel Scally <djrscally@xxxxxxxxx>
---
Changes in v2:

	- Switched to a module registering a platform driver to run
	the dummy ACPI devices, plus an i2c driver to replace and extend
	the existing tps68470 driver
	- Added clock handling functions to the int3472-discrete driver
	- A whole bunch of other changes too numerous to enumerate
 MAINTAINERS                                   |   5 +
 drivers/platform/x86/Kconfig                  |  25 +
 drivers/platform/x86/Makefile                 |   4 +
 .../platform/x86/intel_skl_int3472_common.c   | 100 ++++
 .../platform/x86/intel_skl_int3472_common.h   | 100 ++++
 .../platform/x86/intel_skl_int3472_discrete.c | 496 ++++++++++++++++++
 .../platform/x86/intel_skl_int3472_tps68470.c | 145 +++++
 7 files changed, 875 insertions(+)
 create mode 100644 drivers/platform/x86/intel_skl_int3472_common.c
 create mode 100644 drivers/platform/x86/intel_skl_int3472_common.h
 create mode 100644 drivers/platform/x86/intel_skl_int3472_discrete.c
 create mode 100644 drivers/platform/x86/intel_skl_int3472_tps68470.c

diff --git a/MAINTAINERS b/MAINTAINERS
index a091b496fdd8..c4ed8c3bc58e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9147,6 +9147,11 @@ S:	Maintained
 F:	arch/x86/include/asm/intel_scu_ipc.h
 F:	drivers/platform/x86/intel_scu_*
 
+INTEL SKL INT3472 ACPI DEVICE DRIVER
+M:	Daniel Scally <djrscally@xxxxxxxxx>
+S:	Maintained
+F:	drivers/platform/x86/intel_skl_int3472_*
+
 INTEL SPEED SELECT TECHNOLOGY
 M:	Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx>
 L:	platform-driver-x86@xxxxxxxxxxxxxxx
diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 91e6176cdfbd..916b077df2d5 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -844,6 +844,31 @@ config INTEL_CHT_INT33FE
 	  device and CONFIG_TYPEC_FUSB302=m and CONFIG_BATTERY_MAX17042=m
 	  for Type-C device.
 
+config INTEL_SKL_INT3472
+	tristate "Intel SkyLake ACPI INT3472 Driver"
+	depends on X86 && ACPI
+	select REGMAP_I2C
+	help
+	  This driver adds support for the INT3472 ACPI devices found on some
+	  Intel SkyLake devices.
+
+	  There are 3 kinds of INT3472 ACPI device possible; two for devices
+	  designed for Windows (either with or without a physical tps68470
+	  PMIC) and one designed for Chrome OS. This driver handles all three
+	  situations by discovering information it needs to discern them at
+	  runtime.
+
+	  If your device was designed for Chrome OS, this driver will provide
+	  an ACPI operation region, which must be available before any of the
+	  devices using this are probed. For this reason, you should select Y
+	  if your device was designed for ChromeOS. This option also configures
+	  the designware-i2c driver to be built-in, for the same reason.
+
+	  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"
+
 config INTEL_HID_EVENT
 	tristate "INTEL HID Event"
 	depends on ACPI
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index 581475f59819..ae29c66842ca 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -86,6 +86,10 @@ 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-$(CONFIG_INTEL_SKL_INT3472)		+= intel_skl_int3472.o
+intel_skl_int3472-objs			:= intel_skl_int3472_common.o \
+				   	   intel_skl_int3472_discrete.o \
+				   	   intel_skl_int3472_tps68470.o
 obj-$(CONFIG_INTEL_VBTN)		+= intel-vbtn.o
 
 # MSI
diff --git a/drivers/platform/x86/intel_skl_int3472_common.c b/drivers/platform/x86/intel_skl_int3472_common.c
new file mode 100644
index 000000000000..08cb9d3c06aa
--- /dev/null
+++ b/drivers/platform/x86/intel_skl_int3472_common.c
@@ -0,0 +1,100 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Author: Dan Scally <djrscally@xxxxxxxxx> */
+
+#include <linux/acpi.h>
+#include <linux/i2c.h>
+#include <linux/platform_device.h>
+
+#include "intel_skl_int3472_common.h"
+
+int skl_int3472_get_cldb_buffer(struct acpi_device *adev,
+				struct int3472_cldb *cldb)
+{
+	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+	acpi_handle handle = adev->handle;
+	union acpi_object *obj;
+	acpi_status status;
+	int ret = 0;
+
+	status = acpi_evaluate_object(handle, "CLDB", NULL, &buffer);
+	if (ACPI_FAILURE(status))
+		return -ENODEV;
+
+	obj = buffer.pointer;
+	if (!obj) {
+		dev_err(&adev->dev, "ACPI device has no CLDB object\n");
+		return -ENODEV;
+	}
+
+	if (obj->type != ACPI_TYPE_BUFFER) {
+		dev_err(&adev->dev, "CLDB object is not an ACPI buffer\n");
+		ret = -EINVAL;
+		goto out_free_buff;
+	}
+
+	if (obj->buffer.length > sizeof(*cldb)) {
+		dev_err(&adev->dev, "The CLDB buffer is too large\n");
+		ret = -EINVAL;
+		goto out_free_buff;
+	}
+
+	memcpy(cldb, obj->buffer.pointer, obj->buffer.length);
+
+out_free_buff:
+	kfree(buffer.pointer);
+	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 = 0;
+
+	ret = platform_driver_register(&int3472_discrete);
+	if (ret)
+		return ret;
+
+	ret = i2c_register_driver(THIS_MODULE, &int3472_tps68470);
+	if (ret)
+		goto err_unregister_plat_drv;
+
+	return 0;
+
+err_unregister_plat_drv:
+	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@xxxxxxxxx>");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/platform/x86/intel_skl_int3472_common.h b/drivers/platform/x86/intel_skl_int3472_common.h
new file mode 100644
index 000000000000..9acd0ce7aed9
--- /dev/null
+++ b/drivers/platform/x86/intel_skl_int3472_common.h
@@ -0,0 +1,100 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Author: Dan Scally <djrscally@xxxxxxxxx> */
+#include <linux/regulator/machine.h>
+#include <linux/clk-provider.h>
+#include <linux/gpio/machine.h>
+#include <linux/regulator/driver.h>
+#include <linux/types.h>
+
+/* PMIC GPIO Types */
+#define INT3472_GPIO_TYPE_RESET					0x00
+#define INT3472_GPIO_TYPE_POWERDOWN				0x01
+#define INT3472_GPIO_TYPE_CLK_ENABLE				0x0c
+#define INT3472_GPIO_TYPE_POWER_ENABLE				0x0b
+#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				27
+#define GPIO_REGULATOR_SUPPLY_NAME_LENGTH			9
+
+#define INT3472_REGULATOR(_NAME, _SUPPLY, _OPS)			\
+	(const struct regulator_desc) {				\
+		.name = _NAME,					\
+		.supply_name = _SUPPLY,				\
+		.id = 0,					\
+		.type = REGULATOR_VOLTAGE,			\
+		.ops = _OPS,					\
+		.owner = THIS_MODULE,				\
+	}
+
+#define INT3472_GPIO_FUNCTION_REMAP(_PIN, _FUNCTION)		\
+	(const struct int3472_gpio_function_remap) {		\
+		.documented = _PIN,					\
+		.actual = _FUNCTION				\
+	}
+
+#define to_int3472_clk(hw)					\
+	container_of(hw, struct int3472_gpio_clock, clk_hw)
+
+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_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;
+};
+
+struct int3472_gpio_clock {
+	struct clk *clk;
+	struct clk_hw clk_hw;
+	struct clk_lookup *cl;
+	struct gpio_desc *gpio;
+};
+
+struct int3472_device {
+	struct acpi_device *adev;
+	struct platform_device *pdev;
+	struct acpi_device *sensor;
+	char *sensor_name;
+
+	unsigned int n_gpios; /* how many GPIOs have we seen */
+
+	struct int3472_gpio_regulator regulator;
+	struct int3472_gpio_clock clock;
+
+	unsigned int n_sensor_gpios; /* how many have we mapped to sensor */
+	bool gpios_mapped;
+	struct gpiod_lookup_table gpios;
+};
+
+struct int3472_gpio_function_remap {
+	char *documented;
+	char *actual;
+};
+
+struct int3472_sensor_config {
+	char *sensor_module_name;
+	struct regulator_consumer_supply supply_map;
+	const struct int3472_gpio_function_remap *function_maps;
+};
+
+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);
+int skl_int3472_get_cldb_buffer(struct acpi_device *adev,
+				struct int3472_cldb *cldb);
diff --git a/drivers/platform/x86/intel_skl_int3472_discrete.c b/drivers/platform/x86/intel_skl_int3472_discrete.c
new file mode 100644
index 000000000000..93d250dca92f
--- /dev/null
+++ b/drivers/platform/x86/intel_skl_int3472_discrete.c
@@ -0,0 +1,496 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Author: Dan Scally <djrscally@xxxxxxxxx> */
+
+#include <linux/acpi.h>
+#include <linux/clkdev.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/driver.h>
+
+#include "intel_skl_int3472_common.h"
+
+/* 79234640-9e10-4fea-a5c1-b5aa8b19756f */
+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 */
+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. 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[] = {
+	INT3472_GPIO_FUNCTION_REMAP("reset", NULL),
+	INT3472_GPIO_FUNCTION_REMAP("powerdown", "reset"),
+	{ }
+};
+
+static 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", "i2c-OVTI5648:00"), NULL},
+	/* Surface Go 1&2 - OV5693, Front */
+	{ "YHCU", REGULATOR_SUPPLY("avdd", "i2c-INT33BE:00"), NULL},
+};
+
+/*
+ * 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 = { 0 };
+
+static int skl_int3472_clk_enable(struct clk_hw *hw)
+{
+	struct int3472_gpio_clock *clk = to_int3472_clk(hw);
+
+	gpiod_set_value(clk->gpio, 1);
+
+	return 0;
+}
+
+static void skl_int3472_clk_disable(struct clk_hw *hw)
+{
+	struct int3472_gpio_clock *clk = to_int3472_clk(hw);
+
+	gpiod_set_value(clk->gpio, 0);
+}
+
+static int skl_int3472_clk_prepare(struct clk_hw *hw)
+{
+	/*
+	 * We're just turning a GPIO on to enable, so nothing to do here, but
+	 * we want to provide the op so prepare_enable() works.
+	 */
+	return 0;
+}
+
+static void skl_int3472_clk_unprepare(struct clk_hw *hw)
+{
+	/* Likewise, nothing to do here... */
+}
+
+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,
+};
+
+static struct int3472_sensor_config *
+skl_int3472_get_sensor_module_config(struct int3472_device *int3472)
+{
+	unsigned int i = ARRAY_SIZE(int3472_sensor_configs);
+	struct int3472_sensor_config *ret;
+	union acpi_object *obj;
+
+	obj = acpi_evaluate_dsm_typed(int3472->sensor->handle,
+				      &cio2_sensor_module_guid, 0x00,
+				      0x01, NULL, ACPI_TYPE_STRING);
+
+	if (!obj) {
+		dev_err(&int3472->pdev->dev,
+			"Failed to get sensor module string from _DSM\n");
+		return ERR_PTR(-ENODEV);
+	}
+
+	if (obj->string.type != ACPI_TYPE_STRING) {
+		dev_err(&int3472->pdev->dev,
+			"Sensor _DSM returned a non-string value\n");
+		ret = ERR_PTR(-EINVAL);
+		goto out_free_obj;
+	}
+
+	ret = ERR_PTR(-ENODEV);
+	while (i--) {
+		if (!strcmp(int3472_sensor_configs[i].sensor_module_name,
+			    obj->string.pointer)) {
+			ret = &int3472_sensor_configs[i];
+			goto out_free_obj;
+		}
+	}
+
+out_free_obj:
+	ACPI_FREE(obj);
+	return ret;
+}
+
+static int skl_int3472_map_gpio_to_sensor(struct int3472_device *int3472,
+					  struct acpi_resource *ares,
+					  char *func, u32 polarity)
+{
+	char *path = ares->data.gpio.resource_source.string_ptr;
+	struct int3472_sensor_config *sensor_config;
+	struct gpiod_lookup table_entry;
+	struct acpi_device *adev;
+	acpi_handle handle;
+	acpi_status status;
+	int ret;
+
+	sensor_config = skl_int3472_get_sensor_module_config(int3472);
+	if (!IS_ERR(sensor_config) && sensor_config->function_maps) {
+		unsigned int i = 0;
+
+		while (sensor_config->function_maps[i].documented) {
+			if (!strcmp(func, sensor_config->function_maps[i].documented)) {
+				func = sensor_config->function_maps[i].actual;
+
+				break;
+			}
+
+			i++;
+		}
+	}
+
+	if (!func)
+		return 0;
+
+	if (int3472->n_sensor_gpios >= INT3472_MAX_SENSOR_GPIOS) {
+		dev_warn(&int3472->pdev->dev, "Too many GPIOs mapped\n");
+		return -EINVAL;
+	}
+
+	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 = (struct gpiod_lookup)GPIO_LOOKUP_IDX(acpi_dev_name(adev),
+							   ares->data.gpio.pin_table[0],
+							   func, 0, polarity);
+
+	memcpy(&int3472->gpios.table[int3472->n_sensor_gpios], &table_entry,
+	       sizeof(table_entry));
+
+	int3472->n_sensor_gpios++;
+
+	return 0;
+}
+
+static int skl_int3472_register_clock(struct int3472_device *int3472,
+				      struct acpi_resource *ares)
+{
+	char *path = ares->data.gpio.resource_source.string_ptr;
+	struct clk_init_data init = { };
+	int ret = 0;
+
+	init.name = kasprintf(GFP_KERNEL, "%s-clk",
+			      acpi_dev_name(int3472->adev));
+	init.ops = &skl_int3472_clock_ops;
+
+	int3472->clock.gpio = acpi_get_gpiod(path,
+					     ares->data.gpio.pin_table[0]);
+	if (IS_ERR(int3472->clock.gpio)) {
+		ret = PTR_ERR(int3472->clock.gpio);
+		goto out_free_init_name;
+	}
+
+	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 err_put_gpio;
+	}
+
+	int3472->clock.cl = clkdev_create(int3472->clock.clk, "xvclk",
+					  int3472->sensor_name);
+	if (IS_ERR_OR_NULL(int3472->clock.cl))
+		goto err_unregister_clk;
+
+	goto out_free_init_name;
+
+err_unregister_clk:
+	clk_unregister(int3472->clock.clk);
+err_put_gpio:
+	gpiod_put(int3472->clock.gpio);
+out_free_init_name:
+	kfree(init.name);
+
+	return ret;
+}
+
+static int skl_int3472_register_regulator(struct int3472_device *int3472,
+					  struct acpi_resource *ares)
+{
+	char *path = ares->data.gpio.resource_source.string_ptr;
+	struct int3472_sensor_config *sensor_config;
+	struct regulator_init_data init_data = { };
+	struct regulator_config cfg = { };
+	int ret;
+
+	sensor_config = skl_int3472_get_sensor_module_config(int3472);
+	if (IS_ERR_OR_NULL(sensor_config)) {
+		dev_err(&int3472->pdev->dev, "No sensor module config\n");
+		return PTR_ERR(sensor_config);
+	}
+
+	if (!sensor_config->supply_map.supply) {
+		dev_err(&int3472->pdev->dev, "No supply name defined\n");
+		return -ENODEV;
+	}
+
+	init_data.supply_regulator = NULL;
+	init_data.constraints.valid_ops_mask = REGULATOR_CHANGE_STATUS;
+	init_data.num_consumer_supplies = 1;
+	init_data.consumer_supplies = &sensor_config->supply_map;
+
+	snprintf(int3472->regulator.regulator_name,
+		 GPIO_REGULATOR_NAME_LENGTH, "int3472-discrete-regulator");
+	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_gpiod(path,
+						 ares->data.gpio.pin_table[0]);
+	if (IS_ERR(int3472->regulator.gpio)) {
+		dev_err(&int3472->pdev->dev, "Failed to get 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;
+}
+
+/**
+ * skl_int3472_handle_gpio_resources: maps PMIC resources to consuming sensor
+ * @ares: A pointer to a &struct acpi_resource
+ * @data: A pointer to a &struct int3472_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:
+ * * 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_device *int3472 = data;
+	union acpi_object *obj;
+	int ret = 0;
+
+	if (ares->type != ACPI_RESOURCE_TYPE_GPIO ||
+	    ares->data.gpio.connection_type != ACPI_RESOURCE_GPIO_TYPE_IO)
+		return EINVAL; /* Deliberately positive so parsing continues */
+
+	/*
+	 * n_gpios + 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->n_gpios + 2,
+				      NULL, ACPI_TYPE_INTEGER);
+
+	if (!obj) {
+		dev_warn(&int3472->pdev->dev,
+			 "No _DSM entry for this GPIO pin\n");
+		return ENODEV;
+	}
+
+	switch (obj->integer.value & 0xff) {
+	case INT3472_GPIO_TYPE_RESET:
+		ret = skl_int3472_map_gpio_to_sensor(int3472, ares, "reset",
+						     GPIO_ACTIVE_LOW);
+		if (ret)
+			dev_err(&int3472->pdev->dev,
+				"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)
+			dev_err(&int3472->pdev->dev,
+				"Failed to map powerdown pin to sensor\n");
+
+		break;
+	case INT3472_GPIO_TYPE_CLK_ENABLE:
+		ret = skl_int3472_register_clock(int3472, ares);
+		if (ret)
+			dev_err(&int3472->pdev->dev,
+				"Failed to map clock to sensor\n");
+
+		break;
+	case INT3472_GPIO_TYPE_POWER_ENABLE:
+		ret = skl_int3472_register_regulator(int3472, ares);
+		if (ret) {
+			dev_err(&int3472->pdev->dev,
+				"Failed to map regulator to sensor\n");
+		}
+
+		break;
+	case INT3472_GPIO_TYPE_PRIVACY_LED:
+		ret = skl_int3472_map_gpio_to_sensor(int3472, ares,
+						     "indicator-led",
+						     GPIO_ACTIVE_HIGH);
+		if (ret)
+			dev_err(&int3472->pdev->dev,
+				"Failed to map indicator led to sensor\n");
+
+		break;
+	default:
+		dev_warn(&int3472->pdev->dev,
+			 "GPIO type 0x%llx unknown; the sensor may not work\n",
+			 (obj->integer.value & 0xff));
+		ret = EINVAL;
+	}
+
+	int3472->n_gpios++;
+	ACPI_FREE(obj);
+
+	return ret;
+}
+
+static int skl_int3472_parse_crs(struct int3472_device *int3472)
+{
+	struct list_head resource_list;
+	int ret = 0;
+
+	INIT_LIST_HEAD(&resource_list);
+
+	ret = acpi_dev_get_resources(int3472->adev, &resource_list,
+				     skl_int3472_handle_gpio_resources,
+				     int3472);
+
+	if (!ret) {
+		gpiod_add_lookup_table(&int3472->gpios);
+		int3472->gpios_mapped = true;
+	}
+
+	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_device *int3472;
+	struct int3472_cldb cldb;
+	int ret = 0;
+
+	ret = skl_int3472_get_cldb_buffer(adev, &cldb);
+	if (ret || cldb.control_logic_type != 1)
+		return -EINVAL;
+
+	int3472 = kzalloc(sizeof(*int3472) +
+			 ((INT3472_MAX_SENSOR_GPIOS + 1) * sizeof(struct gpiod_lookup)),
+			 GFP_KERNEL);
+	if (!int3472)
+		return -ENOMEM;
+
+	int3472->adev = adev;
+	int3472->pdev = pdev;
+	platform_set_drvdata(pdev, int3472);
+
+	int3472->sensor = acpi_dev_get_next_dep_dev(adev, NULL);
+	if (!int3472->sensor) {
+		dev_err(&pdev->dev,
+			"This INT3472 entry seems to have no dependents.\n");
+		ret = -ENODEV;
+		goto err_free_int3472;
+	}
+	int3472->sensor_name = i2c_acpi_dev_name(int3472->sensor);
+	int3472->gpios.dev_id = int3472->sensor_name;
+
+	ret = skl_int3472_parse_crs(int3472);
+	if (ret) {
+		skl_int3472_discrete_remove(pdev);
+		goto err_return_ret;
+	}
+
+	return 0;
+
+err_free_int3472:
+	kfree(int3472);
+err_return_ret:
+	return ret;
+}
+
+int skl_int3472_discrete_remove(struct platform_device *pdev)
+{
+	struct int3472_device *int3472;
+
+	int3472 = platform_get_drvdata(pdev);
+
+	if (int3472->gpios_mapped)
+		gpiod_remove_lookup_table(&int3472->gpios);
+
+	if (!IS_ERR_OR_NULL(int3472->regulator.rdev)) {
+		gpiod_put(int3472->regulator.gpio);
+		regulator_unregister(int3472->regulator.rdev);
+	}
+
+	if (!IS_ERR_OR_NULL(int3472->clock.clk)) {
+		gpiod_put(int3472->clock.gpio);
+		clk_unregister(int3472->clock.clk);
+		clkdev_drop(int3472->clock.cl);
+	}
+
+	acpi_dev_put(int3472->sensor);
+
+	kfree(int3472->sensor_name);
+	kfree(int3472);
+
+	return 0;
+}
diff --git a/drivers/platform/x86/intel_skl_int3472_tps68470.c b/drivers/platform/x86/intel_skl_int3472_tps68470.c
new file mode 100644
index 000000000000..9bda65d34987
--- /dev/null
+++ b/drivers/platform/x86/intel_skl_int3472_tps68470.c
@@ -0,0 +1,145 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Author: Dan Scally <djrscally@xxxxxxxxx> */
+
+#include <linux/i2c.h>
+#include <linux/mfd/tps68470.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#include "intel_skl_int3472_common.h"
+
+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%x\n", version);
+
+	return 0;
+}
+
+static struct platform_device *
+skl_int3472_register_pdev(const char *name, struct device *parent)
+{
+	struct platform_device *pdev;
+	int ret;
+
+	pdev = platform_device_alloc(name, PLATFORM_DEVID_NONE);
+	if (IS_ERR_OR_NULL(pdev))
+		return ERR_PTR(-ENOMEM);
+
+	pdev->dev.parent = parent;
+	pdev->driver_override = kstrndup(pdev->name, INT3472_PDEV_MAX_NAME_LEN,
+					 GFP_KERNEL);
+
+	ret = platform_device_add(pdev);
+	if (ret) {
+		platform_device_put(pdev);
+		return ERR_PTR(ret);
+	}
+
+	return pdev;
+}
+
+int skl_int3472_tps68470_probe(struct i2c_client *client)
+{
+	struct acpi_device *adev = ACPI_COMPANION(&client->dev);
+	struct platform_device *regulator_dev;
+	struct platform_device *opregion_dev;
+	struct platform_device *gpio_dev;
+	struct int3472_cldb cldb = { 0 };
+	struct platform_device *clk_dev;
+	bool cldb_present = true;
+	struct regmap *regmap;
+	int ret = 0;
+
+	regmap = devm_regmap_init_i2c(client, &tps68470_regmap_config);
+	if (IS_ERR(regmap)) {
+		dev_err(&client->dev, "devm_regmap_init_i2c Error %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;
+	}
+
+	/*
+	 * 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; crash and burn.
+	 */
+	ret = skl_int3472_get_cldb_buffer(adev, &cldb);
+	if (!ret && cldb.control_logic_type != 2)
+		return -EINVAL;
+
+	if (ret)
+		cldb_present = false;
+
+	gpio_dev = skl_int3472_register_pdev("tps68470-gpio", &client->dev);
+	if (IS_ERR(gpio_dev))
+		return PTR_ERR(gpio_dev);
+
+	if (cldb_present) {
+		clk_dev = skl_int3472_register_pdev("tps68470-clk",
+						    &client->dev);
+		if (IS_ERR(clk_dev)) {
+			ret = PTR_ERR(clk_dev);
+			goto err_free_gpio;
+		}
+
+		regulator_dev = skl_int3472_register_pdev("tps68470-regulator",
+							  &client->dev);
+		if (IS_ERR(regulator_dev)) {
+			ret = PTR_ERR(regulator_dev);
+			goto err_free_clk;
+		}
+	} else {
+		opregion_dev = skl_int3472_register_pdev("tps68470_pmic_opregion",
+							 &client->dev);
+		if (IS_ERR(opregion_dev)) {
+			ret = PTR_ERR(opregion_dev);
+			goto err_free_gpio;
+		}
+	}
+
+	return 0;
+
+err_free_clk:
+	platform_device_put(clk_dev);
+err_free_gpio:
+	platform_device_put(gpio_dev);
+
+	return ret;
+}
-- 
2.25.1