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.pinch...@ideasonboard.com>
Signed-off-by: Daniel Scally <djrsca...@gmail.com>
---
Changes in v3:

        - Added clk_recalc_rate() operation to the clk that's registered, plus
          some associated functions / revisions.
        - Moved source and header files to their own folder within platform/x86
        - Switched the GPIO toggling for the clock from enable/disable to
          prepare/unprepare to avoid any sleep problems
        - Switched handling of the privacy LED GPIO from map-to-sensor to being
          toggled along with the clk enable GPIO; register the clock in
          intel_skl_int3472_parse_crs() instead of during handle_gpio_resources
        - Better commenting in a lot of places
        - Used the sensor_name formed from acpi_dev_name(int3472->sensor) and
          the i2c name format macro as the dev_id in regulator init data rather
          than hardcoding an instance name.
        - Fetched the sensor module config a single time rather than once per
          GPIO
        - Switched int3472-tps68470 driver to use MFD framework properly rather
          than open coding the same functionality
        - A myriad of other fixes too minor to call out.

Suggested changes (from Andy) that I didn't follow:

        - Using clk-gpio.c as a library: The requirement to add clk_recalc_rate
        so that clk_get_rate() would be supported, along with driving the
        privacy LED on clk_enable() meant this wouldn't work I think
        - Leave the MFD driver in its usual place, and prevent the INT3472 from
        probing as an i2c device from ACPI. I definitely see the argument for
        this, but in the end I think probably having all the code for the HID
        within a single place is probably a bit preferable.

 MAINTAINERS                                   |   5 +
 drivers/platform/x86/Kconfig                  |   2 +
 drivers/platform/x86/Makefile                 |   1 +
 drivers/platform/x86/intel-int3472/Kconfig    |  31 +
 drivers/platform/x86/intel-int3472/Makefile   |   4 +
 .../intel-int3472/intel_skl_int3472_common.c  | 106 ++++
 .../intel-int3472/intel_skl_int3472_common.h  | 110 ++++
 .../intel_skl_int3472_discrete.c              | 592 ++++++++++++++++++
 .../intel_skl_int3472_tps68470.c              | 113 ++++
 9 files changed, 964 insertions(+)
 create mode 100644 drivers/platform/x86/intel-int3472/Kconfig
 create mode 100644 drivers/platform/x86/intel-int3472/Makefile
 create mode 100644 
drivers/platform/x86/intel-int3472/intel_skl_int3472_common.c
 create mode 100644 
drivers/platform/x86/intel-int3472/intel_skl_int3472_common.h
 create mode 100644 
drivers/platform/x86/intel-int3472/intel_skl_int3472_discrete.c
 create mode 100644 
drivers/platform/x86/intel-int3472/intel_skl_int3472_tps68470.c

diff --git a/MAINTAINERS b/MAINTAINERS
index a091b496fdd8..cf44b3e77b90 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 SKYLAKE INT3472 ACPI DEVICE DRIVER
+M:     Daniel Scally <djrsca...@gmail.com>
+S:     Maintained
+F:     drivers/platform/x86/intel-int3472/intel_skl_int3472_*
+
 INTEL SPEED SELECT TECHNOLOGY
 M:     Srinivas Pandruvada <srinivas.pandruv...@linux.intel.com>
 L:     platform-driver-...@vger.kernel.org
diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 91e6176cdfbd..9739d30951b6 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -844,6 +844,8 @@ 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
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index 581475f59819..2293b6c3d1c2 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -86,6 +86,7 @@ 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
diff --git a/drivers/platform/x86/intel-int3472/Kconfig 
b/drivers/platform/x86/intel-int3472/Kconfig
new file mode 100644
index 000000000000..b94622245c21
--- /dev/null
+++ b/drivers/platform/x86/intel-int3472/Kconfig
@@ -0,0 +1,31 @@
+config INTEL_SKL_INT3472
+       tristate "Intel SkyLake ACPI INT3472 Driver"
+       depends on ACPI
+       depends on REGULATOR
+       depends on GPIOLIB
+       depends on COMMON_CLK && CLKDEV_LOOKUP
+       depends on I2C
+       select MFD_CORE
+       select REGMAP_I2C
+       help
+         This driver adds support for the INT3472 ACPI devices found on some
+         Intel SkyLake devices.
+
+         The INT3472 is an Intel camera power controller, a logical device
+         found on some 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"
diff --git a/drivers/platform/x86/intel-int3472/Makefile 
b/drivers/platform/x86/intel-int3472/Makefile
new file mode 100644
index 000000000000..c887ee7d52ca
--- /dev/null
+++ b/drivers/platform/x86/intel-int3472/Makefile
@@ -0,0 +1,4 @@
+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
diff --git a/drivers/platform/x86/intel-int3472/intel_skl_int3472_common.c 
b/drivers/platform/x86/intel-int3472/intel_skl_int3472_common.c
new file mode 100644
index 000000000000..f61166b6c497
--- /dev/null
+++ b/drivers/platform/x86/intel-int3472/intel_skl_int3472_common.c
@@ -0,0 +1,106 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Author: Dan Scally <djrsca...@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) {
+               dev_err(&adev->dev, "%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 = 0;
+
+       obj = skl_int3472_get_acpi_buffer(adev, "CLDB");
+       if (IS_ERR(obj))
+               return PTR_ERR(obj);
+
+       if (obj->buffer.length > sizeof(*cldb)) {
+               dev_err(&adev->dev, "The CLDB buffer is too large\n");
+               ret = -EINVAL;
+               goto out_free_obj;
+       }
+
+       memcpy(cldb, obj->buffer.pointer, obj->buffer.length);
+
+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 = 0;
+
+       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 <djrsca...@gmail.com>");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/platform/x86/intel-int3472/intel_skl_int3472_common.h 
b/drivers/platform/x86/intel-int3472/intel_skl_int3472_common.h
new file mode 100644
index 000000000000..9169356cd522
--- /dev/null
+++ b/drivers/platform/x86/intel-int3472/intel_skl_int3472_common.h
@@ -0,0 +1,110 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Author: Dan Scally <djrsca...@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>
+
+/* 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 platform_device;
+struct i2c_client;
+struct acpi_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 {
+       char *documented;
+       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;
+
+       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 n_gpios; /* 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);
+
+#endif
diff --git a/drivers/platform/x86/intel-int3472/intel_skl_int3472_discrete.c 
b/drivers/platform/x86/intel-int3472/intel_skl_int3472_discrete.c
new file mode 100644
index 000000000000..40652161bbbf
--- /dev/null
+++ b/drivers/platform/x86/intel-int3472/intel_skl_int3472_discrete.c
@@ -0,0 +1,592 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Author: Dan Scally <djrsca...@gmail.com> */
+
+#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/overflow.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/driver.h>
+#include <linux/slab.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 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},
+};
+
+/*
+ * 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_prepare(struct clk_hw *hw)
+{
+       struct int3472_gpio_clock *clk = to_int3472_clk(hw);
+
+       gpiod_set_value(clk->ena_gpio, 1);
+       if (clk->led_gpio)
+               gpiod_set_value(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(clk->ena_gpio, 0);
+       if (clk->led_gpio)
+               gpiod_set_value(clk->led_gpio, 0);
+}
+
+static int skl_int3472_clk_enable(struct clk_hw *hw)
+{
+       /*
+        * We're just turning a GPIO on to enable, 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 ret = 0;
+
+       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");
+               goto out_free_buff;
+       }
+
+       ret = *(u32 *)(obj->buffer.pointer + CIO2_SENSOR_SSDB_MCLKSPEED_OFFSET);
+
+out_free_buff:
+       kfree(obj);
+       return ret;
+}
+
+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);
+       struct int3472_discrete_device *int3472 = to_int3472_device(clk);
+
+       return int3472->clock.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,
+};
+
+static struct int3472_sensor_config *
+skl_int3472_get_sensor_module_config(struct int3472_discrete_device *int3472)
+{
+       struct int3472_sensor_config *ret;
+       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");
+               ret = ERR_PTR(-EINVAL);
+               goto out_free_obj;
+       }
+
+       ret = NULL;
+       for (i = 0; i < ARRAY_SIZE(int3472_sensor_configs); i++) {
+               if (!strcmp(int3472_sensor_configs[i].sensor_module_name,
+                           obj->string.pointer)) {
+                       ret = &int3472_sensor_configs[i];
+                       break;
+               }
+       }
+
+out_free_obj:
+       ACPI_FREE(obj);
+       return ret;
+}
+
+static int skl_int3472_map_gpio_to_sensor(struct int3472_discrete_device 
*int3472,
+                                         struct acpi_resource *ares,
+                                         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_OR_NULL(sensor_config) && sensor_config->function_maps) {
+               const struct int3472_gpio_function_remap *remap =
+                       sensor_config->function_maps;
+
+               for (; 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_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_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%hx for clock\n",
+                       type);
+               break;
+       }
+
+       return 0;
+}
+
+static 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 = 0;
+
+       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;
+       }
+
+       goto out_free_init_name;
+
+err_unregister_clk:
+       clk_unregister(int3472->clock.clk);
+out_free_init_name:
+       kfree(init.name);
+
+       return ret;
+}
+
+static int skl_int3472_register_regulator(struct int3472_discrete_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 = int3472->sensor_config;
+       if (IS_ERR_OR_NULL(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;
+       sensor_config->supply_map.dev_name = int3472->sensor_name;
+       init_data.consumer_supplies = &sensor_config->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_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 lines\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: 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:
+ * * 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;
+       u16 pin = ares->data.gpio.pin_table[0];
+       union acpi_object *obj;
+       char *err_msg;
+       int ret = 0;
+       u8 type;
+
+       if (ares->type != ACPI_RESOURCE_TYPE_GPIO ||
+           ares->data.gpio.connection_type != ACPI_RESOURCE_GPIO_TYPE_IO)
+               return 1; /* 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->dev, "No _DSM entry for GPIO pin %u\n", pin);
+               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;
+       }
+
+       if (ret < 0 && ret != -EPROBE_DEFER)
+               dev_err(int3472->dev, err_msg);
+
+       int3472->n_gpios++;
+       ACPI_FREE(obj);
+
+       return ret;
+}
+
+static int skl_int3472_parse_crs(struct int3472_discrete_device *int3472)
+{
+       struct list_head resource_list;
+       int ret;
+
+       INIT_LIST_HEAD(&resource_list);
+
+       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 (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 = kzalloc(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_dependent_dev(adev);
+       if (IS_ERR_OR_NULL(int3472->sensor)) {
+               dev_err(&pdev->dev,
+                       "INT3472 seems to have no dependents.\n");
+               ret = -ENODEV;
+               goto err_free_int3472;
+       }
+       get_device(&int3472->sensor->dev);
+
+       int3472->sensor_name = kasprintf(GFP_KERNEL, I2C_DEV_NAME_FORMAT,
+                                        acpi_dev_name(int3472->sensor));
+
+       ret = skl_int3472_parse_crs(int3472);
+       if (ret) {
+               skl_int3472_discrete_remove(pdev);
+               return ret;
+       }
+
+       return 0;
+
+err_free_int3472:
+       kfree(int3472);
+       return ret;
+}
+
+int skl_int3472_discrete_remove(struct platform_device *pdev)
+{
+       struct int3472_discrete_device *int3472 = platform_get_drvdata(pdev);
+
+       if (int3472->gpios.dev_id)
+               gpiod_remove_lookup_table(&int3472->gpios);
+
+       if (!IS_ERR(int3472->regulator.rdev))
+               regulator_unregister(int3472->regulator.rdev);
+
+       if (!IS_ERR(int3472->clock.clk))
+               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);
+
+       acpi_dev_put(int3472->sensor);
+
+       kfree(int3472->sensor_name);
+       kfree(int3472);
+
+       return 0;
+}
diff --git a/drivers/platform/x86/intel-int3472/intel_skl_int3472_tps68470.c 
b/drivers/platform/x86/intel-int3472/intel_skl_int3472_tps68470.c
new file mode 100644
index 000000000000..d0d2391e263f
--- /dev/null
+++ b/drivers/platform/x86/intel-int3472/intel_skl_int3472_tps68470.c
@@ -0,0 +1,113 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Author: Dan Scally <djrsca...@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"
+
+static const struct mfd_cell tps68470_c[] = {
+       { .name = "tps68470-gpio" },
+       { .name = "tps68470_pmic_opregion" },
+};
+
+static const struct mfd_cell tps68470_w[] = {
+       { .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;
+}
+
+int skl_int3472_tps68470_probe(struct i2c_client *client)
+{
+       struct acpi_device *adev = ACPI_COMPANION(&client->dev);
+       struct int3472_cldb cldb = { 0 };
+       bool cldb_present = true;
+       struct regmap *regmap;
+       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;
+       }
+
+       /*
+        * 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.
+        */
+       ret = skl_int3472_fill_cldb(adev, &cldb);
+       if (!ret && cldb.control_logic_type != 2) {
+               dev_err(&client->dev, "Unsupported control logic type %u\n",
+                       cldb.control_logic_type);
+               return -EINVAL;
+       }
+
+       if (ret)
+               cldb_present = false;
+
+       if (cldb_present)
+               ret = devm_mfd_add_devices(&client->dev, PLATFORM_DEVID_NONE,
+                                          tps68470_w, ARRAY_SIZE(tps68470_w),
+                                          NULL, 0, NULL);
+       else
+               ret = devm_mfd_add_devices(&client->dev, PLATFORM_DEVID_NONE,
+                                          tps68470_c, ARRAY_SIZE(tps68470_c),
+                                          NULL, 0, NULL);
+
+       if (ret) {
+               dev_err(&client->dev, "Failed to add MFD devices\n");
+               return ret;
+       }
+
+       return 0;
+}
-- 
2.25.1

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