Re: [PATCH 18/18] ipu3: Add driver for dummy INT3472 ACPI device

[Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>]

Hello,

On Mon, Nov 30, 2020 at 04:29:04PM +0000, Kieran Bingham wrote:
> On 30/11/2020 13:31, Daniel Scally wrote:
> > On platforms where ACPI is designed for use with Windows, resources
> > that are intended to be consumed by sensor devices are sometimes in
> > the _CRS of a dummy INT3472 device upon which the sensor depends. This
> > driver binds to the dummy acpi device (which does not represent a
> > physical PMIC) and maps them into GPIO lines and regulators for use by
> > the sensor device instead.
> > 
> > Suggested-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> > Signed-off-by: Daniel Scally <djrscally@xxxxxxxxx>
> > ---
> > Changes since RFC v3:
> > 
> > 	- Patch introduced
> > 
> > This patch contains the bits of this process that we're least sure about.
> > The sensors in scope for this work are called out as dependent (in their
> > DSDT entry's _DEP) on a device with _HID INT3472. These come in at least
> > 2 kinds; those with an I2cSerialBusV2 entry (which we presume therefore
> > are legitimate tps68470 PMICs that need handling by those drivers - work
> > on that in the future). And those without an I2C device. For those without
> > an I2C device they instead have an array of GPIO pins defined in _CRS.

Those are called "discrete regulators", and can also be identified by
the type reported in the CLDB. They're not regulators, just ACPI device
objects that group a set of GPIOs and a referenced from the consumers of
those GPIOs. I'll refrain here from sharing my opinion on the ACPI
design...

> > So
> > for example, my Lenovo Miix 510's OVTI2680 sensor is dependent on one of
> > the _latter_ kind of INT3472 devices, with this _CRS:
> > 
> > Method (_CRS, 0, NotSerialized)  // _CRS: Current Resource Settings
> > {
> >     Name (SBUF, ResourceTemplate ()
> >     {
> >         GpioIo (Exclusive, PullDefault, 0x0000, 0x0000,
> > 	    IoRestrictionOutputOnly, "\\_SB.PCI0.GPI0",
> > 	    0x00, ResourceConsumer, ,
> >             )
> >             {   // Pin list
> >                 0x0079
> >             }
> >         GpioIo (Exclusive, PullDefault, 0x0000, 0x0000,
> > 	    IoRestrictionOutputOnly, "\\_SB.PCI0.GPI0",
> > 	    0x00, ResourceConsumer, ,
> >             )
> >             {   // Pin list
> >                 0x007A
> >             }
> >         GpioIo (Exclusive, PullDefault, 0x0000, 0x0000,
> > 	    IoRestrictionOutputOnly, "\\_SB.PCI0.GPI0",
> > 	    0x00, ResourceConsumer, ,
> >             )
> >             {   // Pin list
> >                 0x008F
> >             }
> >     })
> >     Return (SBUF) /* \_SB_.PCI0.PMI1._CRS.SBUF */
> > }
> > 
> > and the same device has a _DSM Method, which returns 32-bit ints where
> > the second lowest byte we noticed to match the pin numbers of the GPIO
> > lines:
> > 
> > Method (_DSM, 4, NotSerialized)  // _DSM: Device-Specific Method
> > {
> >     If ((Arg0 == ToUUID ("79234640-9e10-4fea-a5c1-b5aa8b19756f")))
> >     {
> >         If ((Arg2 == One))
> >         {
> >             Return (0x03)
> >         }
> > 
> >         If ((Arg2 == 0x02))
> >         {
> >             Return (0x01007900)
> >         }
> > 
> >         If ((Arg2 == 0x03))
> >         {
> >             Return (0x01007A0C)
> >         }
> > 
> >         If ((Arg2 == 0x04))
> >         {
> >             Return (0x01008F01)
> >         }
> >     }
> > 
> >     Return (Zero)
> > }
> > 
> > We know that at least some of those pins have to be toggled active for the
> > sensor devices to be available in i2c, so the conclusion we came to was
> > that those GPIO entries assigned to the INT3472 device actually represent
> > GPIOs and regulators to be consumed by the sensors themselves. Tsuchiya
> > noticed that the lowest byte in the return values of the _DSM method
> > seemed to represent the type or function of the GPIO line, and we
> > confirmed that by testing on each surface device that GPIO lines where the
> > low byte in the _DSM entry for that pin was 0x0d controlled the privacy
> > LED of the cameras.
> > 
> > We're guessing as to the exact meaning of the function byte, but I
> > conclude they're something like this:
> > 
> > 0x00 - probably a reset GPIO
> > 0x01 - regulator for the sensor

I think 0x01 is probably a power down GPIO.

> > 0x0c - regulator for the sensor
> > 0x0b - regulator again, but for a VCM or EEPROM
> > 0x0d - privacy led (only one we're totally confident of since we can see
> >        it happen!)
> > 
> > After much internal debate I decided to write this as a standalone
> > acpi_driver. Alternative options we considered:
> > 
> > 1. Squash all this into the cio2-bridge code, which I did originally write
> > but decided I didn't like.
> > 2. Extend the existing tps68470 mfd driver...they share an ACPI ID so this
> > kinda makes sense, but ultimately given there is no actual physical
> > tps68470 in the scenario this patch handles I decided I didn't like this
> > either.
> 
> I would agree, keeping this in a unit file on it's own makes sense to me.
> 
> I'm a bit worried about what happens if the tps68470 is also compiled
> in... Does the right device get mapped in the event that there are also
> actual devices already supported by the tps68470 mfd driver on the
> device as well?

That's my main concern here, two drivers for the same device won't play
well together. We'll need to at least teach the tps68470 driver to
ignore the "discrete regulators".

I however believe this would be better handled in the cio2-bridge
driver, given that the ACPI device object doesn't represent an actual
device.

> >  MAINTAINERS                            |   7 +
> >  drivers/media/pci/intel/ipu3/Kconfig   |  14 +
> >  drivers/media/pci/intel/ipu3/Makefile  |   1 +
> >  drivers/media/pci/intel/ipu3/int3472.c | 381 +++++++++++++++++++++++++
> >  drivers/media/pci/intel/ipu3/int3472.h |  96 +++++++
> >  5 files changed, 499 insertions(+)
> >  create mode 100644 drivers/media/pci/intel/ipu3/int3472.c
> >  create mode 100644 drivers/media/pci/intel/ipu3/int3472.h
> > 
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 188559a0a610..d73471f9c2a3 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -8753,6 +8753,13 @@ L:	linux-crypto@xxxxxxxxxxxxxxx
> >  S:	Maintained
> >  F:	drivers/crypto/inside-secure/
> >  
> > +INT3472 ACPI DEVICE DRIVER
> > +M:	Daniel Scally <djrscally@xxxxxxxxx>
> > +L:	linux-media@xxxxxxxxxxxxxxx
> > +S:	Maintained
> > +F:	drivers/media/pci/intel/ipu3/int3472.c
> > +F:	drivers/media/pci/intel/ipu3/int3472.h
> > +
> >  INTEGRITY MEASUREMENT ARCHITECTURE (IMA)
> >  M:	Mimi Zohar <zohar@xxxxxxxxxxxxx>
> >  M:	Dmitry Kasatkin <dmitry.kasatkin@xxxxxxxxx>
> > diff --git a/drivers/media/pci/intel/ipu3/Kconfig b/drivers/media/pci/intel/ipu3/Kconfig
> > index 2b3350d042be..9dd3b280f821 100644
> > --- a/drivers/media/pci/intel/ipu3/Kconfig
> > +++ b/drivers/media/pci/intel/ipu3/Kconfig
> > @@ -34,3 +34,17 @@ config CIO2_BRIDGE
> >  		- Dell 7285
> >  
> >  	  If in doubt, say N here.
> > +
> > +config INT3472
> > +	tristate "INT3472 Dummy ACPI Device Driver"
> > +	depends on VIDEO_IPU3_CIO2
> > +	depends on ACPI && REGULATOR && GPIOLIB
> > +	help
> > +	  This module provides an ACPI driver for INT3472 devices that do not
> > +	  represent an actual physical tps68470 device.
> > +
> > +	  Say Y here if your device is a detachable / hybrid laptop that comes
> > +	  with Windows installed by the OEM.
> > +	  The module will be called int3472.
> > +
> > +	  If in doubt, say N here.
> > diff --git a/drivers/media/pci/intel/ipu3/Makefile b/drivers/media/pci/intel/ipu3/Makefile
> > index 933777e6ea8a..2285947b2bd2 100644
> > --- a/drivers/media/pci/intel/ipu3/Makefile
> > +++ b/drivers/media/pci/intel/ipu3/Makefile
> > @@ -1,5 +1,6 @@
> >  # SPDX-License-Identifier: GPL-2.0-only
> >  obj-$(CONFIG_VIDEO_IPU3_CIO2) += ipu3-cio2.o
> > +obj-$(CONFIG_INT3472) += int3472.o
> >  
> >  ipu3-cio2-y += ipu3-cio2-main.o
> >  ipu3-cio2-$(CONFIG_CIO2_BRIDGE) += cio2-bridge.o
> > diff --git a/drivers/media/pci/intel/ipu3/int3472.c b/drivers/media/pci/intel/ipu3/int3472.c
> > new file mode 100644
> > index 000000000000..6b0be75f7f35
> > --- /dev/null
> > +++ b/drivers/media/pci/intel/ipu3/int3472.c
> > @@ -0,0 +1,381 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/* Author: Dan Scally <djrscally@xxxxxxxxx> */
> > +#include <linux/acpi.h>
> > +#include <linux/gpio/consumer.h>
> > +#include <linux/gpio/machine.h>
> > +#include <linux/i2c.h>
> > +#include <linux/kernel.h>
> > +#include <linux/list.h>
> > +#include <linux/module.h>
> > +#include <linux/regulator/driver.h>
> > +
> > +#include "int3472.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 = { 0 };
> > +
> > +static int int3472_map_gpio_to_sensor(struct int3472_device *int3472,
> > +				      struct acpi_resource *ares, char *func)
> > +{
> > +	char *path = ares->data.gpio.resource_source.string_ptr;
> > +	struct gpiod_lookup table_entry;
> > +	struct acpi_device *adev;
> > +	acpi_handle handle;
> > +	acpi_status status;
> > +	int ret;
> > +
> > +	/* Make sure we don't overflow, and leave room for a terminator */
> > +	if (int3472->n_sensor_gpios >= INT3472_MAX_SENSOR_GPIOS) {
> > +		dev_warn(&int3472->sensor->dev, "Too many GPIOs mapped\n");
> > +		return -EINVAL;
> > +	}
> > +
> > +	/* Fetch ACPI handle for the GPIO chip  */
> > +	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, GPIO_ACTIVE_HIGH);
> > +
> > +	memcpy(&int3472->gpios.table[int3472->n_sensor_gpios], &table_entry,
> > +	       sizeof(table_entry));
> > +	int3472->n_sensor_gpios++;
> > +
> > +	return 0;
> > +}
> > +
> > +static struct int3472_sensor_regulator_map *
> > +int3472_get_sensor_supply_map(struct int3472_device *int3472)
> > +{
> > +	struct int3472_sensor_regulator_map *ret;
> > +	union acpi_object *obj;
> > +	unsigned int i;
> > +
> > +	/*
> > +	 * Sensor modules seem to be identified by a unique string. We use that
> > +	 * to make sure we pass the right device and supply names to the new
> > +	 * regulator's consumer_supplies
> > +	 */
> > +	obj = acpi_evaluate_dsm_typed(int3472->sensor->handle,
> > +				      &cio2_sensor_module_guid, 0x00,
> > +				      0x01, NULL, ACPI_TYPE_STRING);
> > +
> > +	if (!obj) {
> > +		dev_err(&int3472->sensor->dev,
> > +			"Failed to get sensor module string from _DSM\n");
> > +		return ERR_PTR(-ENODEV);
> > +	}
> > +
> > +	if (obj->string.type != ACPI_TYPE_STRING) {
> > +		dev_err(&int3472->sensor->dev,
> > +			"Sensor _DSM returned a non-string value\n");
> > +		ret = ERR_PTR(-EINVAL);
> > +		goto out_free_obj;
> > +	}
> > +
> > +	ret = ERR_PTR(-ENODEV);
> > +	for (i = 0; i < ARRAY_SIZE(int3472_sensor_regulator_maps); i++) {
> > +		if (!strcmp(int3472_sensor_regulator_maps[i].sensor_module_name,
> > +			    obj->string.pointer)) {
> > +			ret = &int3472_sensor_regulator_maps[i];
> > +			goto out_free_obj;
> > +		}
> > +	}
> > +
> > +out_free_obj:
> > +	ACPI_FREE(obj);
> > +	return ret;
> > +}
> > +
> > +static int int3472_register_regulator(struct int3472_device *int3472,
> > +				      struct acpi_resource *ares)
> > +{
> > +	char *path = ares->data.gpio.resource_source.string_ptr;
> > +	struct int3472_sensor_regulator_map *regulator_map;
> > +	struct regulator_init_data init_data = { };
> > +	struct int3472_gpio_regulator *regulator;
> > +	struct regulator_config cfg = { };
> > +	int ret;
> > +
> > +	/*
> > +	 * We lookup supply names from machine specific tables, based on a
> > +	 * unique identifier in the sensor's _DSM
> > +	 */
> > +	regulator_map = int3472_get_sensor_supply_map(int3472);
> > +	if (IS_ERR_OR_NULL(regulator_map)) {
> > +		dev_err(&int3472->sensor->dev,
> > +			"Found no supplies defined for this sensor\n");
> > +		return PTR_ERR(regulator_map);
> > +	}
> > +
> > +	if (int3472->n_regulators >= regulator_map->n_supplies) {
> > +		dev_err(&int3472->sensor->dev,
> > +			"All known supplies are already mapped\n");
> > +		return -EINVAL;
> > +	}
> > +
> > +	init_data.supply_regulator = NULL;
> > +	init_data.constraints.valid_ops_mask = REGULATOR_CHANGE_STATUS;
> > +	init_data.num_consumer_supplies = 1;
> > +	init_data.consumer_supplies = &regulator_map->supplies[int3472->n_regulators];
> > +
> > +	regulator = kmalloc(sizeof(*regulator), GFP_KERNEL);
> > +	if (!regulator)
> > +		return -ENOMEM;
> > +
> > +	snprintf(regulator->regulator_name, GPIO_REGULATOR_NAME_LENGTH,
> > +		 "gpio-regulator-%d", int3472->n_regulators);
> > +	snprintf(regulator->supply_name, GPIO_REGULATOR_SUPPLY_NAME_LENGTH,
> > +		 "supply-%d", int3472->n_regulators);
> > +
> > +	regulator->rdesc = INT3472_REGULATOR(regulator->regulator_name,
> > +					     regulator->supply_name,
> > +					     int3472->n_regulators,
> > +					     &int3472_gpio_regulator_ops);
> > +
> > +	regulator->gpio = acpi_get_gpiod(path, ares->data.gpio.pin_table[0]);
> > +	if (IS_ERR(regulator->gpio)) {
> > +		ret = PTR_ERR(regulator->gpio);
> > +		goto err_free_regulator;
> > +	}
> > +
> > +	cfg.dev = &int3472->adev->dev;
> > +	cfg.init_data = &init_data;
> > +	cfg.ena_gpiod = regulator->gpio;
> > +
> > +	regulator->rdev = regulator_register(&regulator->rdesc, &cfg);
> > +	if (IS_ERR(regulator->rdev)) {
> > +		ret = PTR_ERR(regulator->rdev);
> > +		goto err_free_gpio;
> > +	}
> > +
> > +	list_add(&regulator->list, &int3472->regulators);
> > +	int3472->n_regulators++;
> > +
> > +	return 0;
> > +
> > +err_free_gpio:
> > +	gpiod_put(regulator->gpio);
> > +err_free_regulator:
> > +	kfree(regulator);
> > +
> > +	return ret;
> > +}
> > +
> > +static int 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 */
> > +
> > +	/*
> > +	 * 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->adev->dev,
> > +			 "No _DSM entry for this GPIO pin\n");
> > +		return ENODEV;
> > +	}
> > +
> > +	switch (obj->integer.value & 0xff) { /* low byte holds type data */
> > +	case 0x00: /* Purpose unclear, possibly a reset GPIO pin */
> > +		ret = int3472_map_gpio_to_sensor(int3472, ares, "reset");
> > +		if (ret)
> > +			dev_warn(&int3472->adev->dev,
> > +				 "Failed to map reset pin to sensor\n");
> > +
> > +		break;
> > +	case 0x01: /* Power regulators (we think) */
> > +	case 0x0c:
> 
> A little annoying that 0x0c is before 0x0b ... but I see this is sharing
> with 0x01, so I think this can stay like this.
> 
> It might be nice to wrap the values in some descriptive #defines though,
> but I'm not sure what we'd call them, and if we're not yet sure on their
> purposes - perhaps the raw values are better for now. We'll see I guess.
> 
> > +		ret = int3472_register_regulator(int3472, ares);
> > +		if (ret)
> > +			dev_warn(&int3472->adev->dev,
> > +				 "Failed to map regulator to sensor\n");
> > +
> > +		break;
> > +	case 0x0b: /* Power regulators, but to a device separate to sensor */
> > +		ret = int3472_register_regulator(int3472, ares);
> > +		if (ret)
> > +			dev_warn(&int3472->adev->dev,
> > +				 "Failed to map regulator to sensor\n");
> > +
> > +		break;
> > +	case 0x0d: /* Indicator LEDs */
> > +		ret = int3472_map_gpio_to_sensor(int3472, ares, "indicator-led");
> > +		if (ret)
> > +			dev_warn(&int3472->adev->dev,
> > +				 "Failed to map indicator led to sensor\n");
> > +
> > +		break;
> > +	default:
> > +		/* if we've gotten here, we're not sure what they are yet */
> > +		dev_warn(&int3472->adev->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 abs(ret);
> > +}
> > +
> > +static void int3472_parse_crs(struct int3472_device *int3472)
> > +{
> > +	struct list_head resource_list;
> > +
> > +	INIT_LIST_HEAD(&resource_list);
> > +
> > +	acpi_dev_get_resources(int3472->adev, &resource_list,
> > +			       int3472_handle_gpio_resources, int3472);
> > +
> > +	acpi_dev_free_resource_list(&resource_list);
> > +	gpiod_add_lookup_table(&int3472->gpios);
> > +}
> > +
> > +static int int3472_add(struct acpi_device *adev)
> > +{
> > +	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
> > +	struct int3472_device *int3472;
> > +	struct int3472_cldb cldb;
> > +	union acpi_object *obj;
> > +	acpi_status status;
> > +	int ret = 0;
> > +
> > +	/*
> > +	 * This driver is only intended to support "dummy" INT3472 devices
> > +	 * which appear in ACPI designed for Windows. These are distinguishable
> > +	 * from INT3472 entries representing an actual tps68470 PMIC through
> > +	 * the presence of a CLDB buffer with a particular value set.
> > +	 */
> > +	status = acpi_evaluate_object(adev->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);
> > +
> > +	/*
> > +	 * control_logic_type = 1 indicates this is a dummy INT3472 device of
> > +	 * the kind we're looking for. If any other value then we shouldn't try
> > +	 * to handle it
> > +	 */
> > +	if (cldb.control_logic_type != 1) {
> > +		ret = -EINVAL;
> > +		goto out_free_buff;
> > +	}
> > +
> > +	/* Space for 4 GPIOs - one more than we've seen so far plus a null */
> > +	int3472 = kzalloc(sizeof(*int3472) +
> > +			 ((INT3472_MAX_SENSOR_GPIOS + 1) * sizeof(struct gpiod_lookup)),
> > +			 GFP_KERNEL);
> > +	if (!int3472) {
> > +		ret = -ENOMEM;
> > +		goto out_free_buff;
> > +	}
> > +
> > +	int3472->adev = adev;
> > +	adev->driver_data = int3472;
> > +
> > +	int3472->sensor = acpi_dev_get_next_dep_dev(adev, NULL);
> > +	if (!int3472->sensor) {
> > +		dev_err(&adev->dev,
> > +			"This INT3472 entry seems to have no dependents.\n");
> > +		ret = -ENODEV;
> > +		goto out_free_int3472;
> > +	}
> > +
> > +	int3472->gpios.dev_id = i2c_acpi_dev_name(int3472->sensor);
> > +
> > +	INIT_LIST_HEAD(&int3472->regulators);
> > +
> > +	int3472_parse_crs(int3472);
> > +
> > +	goto out_free_buff;
> > +
> > +out_free_int3472:
> > +	kfree(int3472);
> > +out_free_buff:
> > +	kfree(buffer.pointer);
> > +	return ret;
> > +}
> > +
> > +static int int3472_remove(struct acpi_device *adev)
> > +{
> > +	struct int3472_gpio_regulator *reg;
> > +	struct int3472_device *int3472;
> > +
> > +	int3472 = acpi_driver_data(adev);
> > +
> > +	acpi_dev_put(int3472->sensor);
> > +	gpiod_remove_lookup_table(&int3472->gpios);
> > +
> > +	list_for_each_entry(reg, &int3472->regulators, list) {
> > +		gpiod_put(reg->gpio);
> > +		regulator_unregister(reg->rdev);
> > +	}
> > +
> > +	kfree(int3472);
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct acpi_device_id int3472_device_id[] = {
> > +	{ "INT3472", 0 },
> > +	{ },
> > +};
> > +MODULE_DEVICE_TABLE(acpi, int3472_device_id);
> > +
> > +static struct acpi_driver int3472_driver = {
> > +	.name = "int3472",
> > +	.ids = int3472_device_id,
> > +	.ops = {
> > +		.add = int3472_add,
> > +		.remove = int3472_remove,
> > +	},
> > +	.owner = THIS_MODULE,
> > +};
> > +
> > +module_acpi_driver(int3472_driver);
> > +
> > +MODULE_LICENSE("GPL v2");
> > +MODULE_AUTHOR("Dan Scally <djrscally@xxxxxxxxx>");
> > +MODULE_DESCRIPTION("ACPI Driver for Discrete type INT3472 ACPI Devices");
> > diff --git a/drivers/media/pci/intel/ipu3/int3472.h b/drivers/media/pci/intel/ipu3/int3472.h
> > new file mode 100644
> > index 000000000000..6964726e8e1f
> > --- /dev/null
> > +++ b/drivers/media/pci/intel/ipu3/int3472.h
> > @@ -0,0 +1,96 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/* Author: Dan Scally <djrscally@xxxxxxxxx> */
> > +#include <linux/regulator/machine.h>
> > +
> > +#define INT3472_MAX_SENSOR_GPIOS			3
> > +#define GPIO_REGULATOR_NAME_LENGTH			17
> > +#define GPIO_REGULATOR_SUPPLY_NAME_LENGTH		9
> > +
> > +#define INT3472_REGULATOR(_NAME, _SUPPLY, _ID, _OPS)	\
> > +	((const struct regulator_desc) {		\
> > +		.name = _NAME,				\
> > +		.supply_name = _SUPPLY,			\
> > +		.id = _ID,				\
> > +		.type = REGULATOR_VOLTAGE,		\
> > +		.ops = _OPS,				\
> > +		.owner = THIS_MODULE,			\
> > +	})
> > +
> > +const guid_t int3472_gpio_guid = GUID_INIT(0x79234640, 0x9e10, 0x4fea,
> > +					     0xa5, 0xc1, 0xb5, 0xaa, 0x8b,
> > +					     0x19, 0x75, 0x6f);
> > +
> > +const guid_t cio2_sensor_module_guid = GUID_INIT(0x822ace8f, 0x2814, 0x4174,
> > +						 0xa5, 0x6b, 0x5f, 0x02, 0x9f,
> > +						 0xe0, 0x79, 0xee);
> > +
> > +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_device {
> > +	struct acpi_device *adev;
> > +	struct acpi_device *sensor;
> > +
> > +	unsigned int n_gpios; /* how many GPIOs have we seen */
> > +
> > +	unsigned int n_regulators;
> > +	struct list_head regulators;
> > +
> > +	unsigned int n_sensor_gpios; /* how many have we mapped to sensor */
> > +	struct gpiod_lookup_table gpios;
> > +};
> > +
> > +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 list_head list;
> > +};
> > +
> > +struct int3472_sensor_regulator_map {
> > +	char *sensor_module_name;
> > +	unsigned int n_supplies;
> > +	struct regulator_consumer_supply *supplies;
> > +};
> > +
> 
> I think the data tables below can be moved to the .c file, and also
> marked as static const.
> 
> > +/*
> > + * Here follows platform specific mapping information that we can pass to
> > + * regulator_init_data when we register our regulators. They're just mapped
> > + * via index, I.E. the first regulator pin that the code finds for the
> > + * i2c-OVTI2680:00 device is avdd, the second is dovdd and so on.
> > + */
> > +
> > +static struct regulator_consumer_supply miix_510_ov2680[] = {
> > +	{ "i2c-OVTI2680:00", "avdd" },
> > +	{ "i2c-OVTI2680:00", "dovdd" },
> > +};
> > +
> > +static struct regulator_consumer_supply surface_go2_ov5693[] = {
> > +	{ "i2c-INT33BE:00", "avdd" },
> > +	{ "i2c-INT33BE:00", "dovdd" },
> > +};
> > +
> > +static struct regulator_consumer_supply surface_book_ov5693[] = {
> > +	{ "i2c-INT33BE:00", "avdd" },
> > +	{ "i2c-INT33BE:00", "dovdd" },
> > +};
> 
> Should we de-duplicate repeated identical entries?
> 
> for instance, if we 'know' the surface range all uses the same
> configuration, or at least a reduced set of configuration we could point
> to a single definition for the each set, rather than a specific one for
> each device perhaps?
> 
> > +
> > +static struct int3472_sensor_regulator_map int3472_sensor_regulator_maps[] = {
> > +	{ "GNDF140809R", 2, miix_510_ov2680 },
> > +	{ "YHCU", 2, surface_go2_ov5693 },
> > +	{ "MSHW0070", 2, surface_book_ov5693 },
> > +};

-- 
Regards,

Laurent Pinchart