Commit e64e8498 authored by Hans de Goede's avatar Hans de Goede Committed by Rafael J. Wysocki
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platform/x86: Add ACPI i2c-multi-instantiate pseudo driver 



On systems with ACPI instantiated i2c-clients, normally there is 1 fw_node
per i2c-device and that fw-node contains 1 I2cSerialBus resource for that 1
i2c-device.

But in some rare cases the manufacturer has decided to describe multiple
i2c-devices in a single ACPI fwnode with multiple I2cSerialBus resources.

An earlier attempt to fix this in the i2c-core resulted in a lot of extra
code to support this corner-case.

This commit introduces a new i2c-multi-instantiate driver which fixes this
in a different way. This new driver can be built as a module which will
only loaded on affected systems.

This driver will instantiate a new i2c-client per I2cSerialBus resource,
using the driver_data from the acpi_device_id it is binding to to tell it
which chip-type (and optional irq-resource) to use when instantiating.

Note this driver depends on a platform device being instantiated for the
ACPI fwnode, see the i2c_multi_instantiate_ids list of ACPI device-ids in
drivers/acpi/scan.c: acpi_device_enumeration_by_parent().

Acked-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: default avatarWolfram Sang <wsa@the-dreams.de>
Signed-off-by: default avatarHans de Goede <hdegoede@redhat.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 21ba074c

MAINTAINERS

+6 −0
Original line number Diff line number Diff line
@@ -367,6 +367,12 @@ L: linux-acpi@vger.kernel.org 
S:	Maintained

F:	drivers/acpi/arm64



ACPI I2C MULTI INSTANTIATE DRIVER

M:	Hans de Goede <hdegoede@redhat.com>

L:	platform-driver-x86@vger.kernel.org

S:	Maintained

F:	drivers/platform/x86/i2c-multi-instantiate.c



ACPI PMIC DRIVERS

M:	"Rafael J. Wysocki" <rjw@rjwysocki.net>

M:	Len Brown <lenb@kernel.org>

drivers/platform/x86/Kconfig

+11 −0
Original line number Diff line number Diff line
@@ -1218,6 +1218,17 @@ config INTEL_CHTDC_TI_PWRBTN 
	  To compile this driver as a module, choose M here: the module

	  will be called intel_chtdc_ti_pwrbtn.



config I2C_MULTI_INSTANTIATE

	tristate "I2C multi instantiate pseudo device driver"

	depends on I2C && ACPI

	help

	  Some ACPI-based systems list multiple i2c-devices in a single ACPI

	  firmware-node. This driver will instantiate separate i2c-clients

	  for each device in the firmware-node.



	  To compile this driver as a module, choose M here: the module

	  will be called i2c-multi-instantiate.



endif # X86_PLATFORM_DEVICES



config PMC_ATOM

drivers/platform/x86/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -91,3 +91,4 @@ obj-$(CONFIG_PMC_ATOM) += pmc_atom.o 
obj-$(CONFIG_MLX_PLATFORM)	+= mlx-platform.o

obj-$(CONFIG_INTEL_TURBO_MAX_3) += intel_turbo_max_3.o

obj-$(CONFIG_INTEL_CHTDC_TI_PWRBTN)	+= intel_chtdc_ti_pwrbtn.o

obj-$(CONFIG_I2C_MULTI_INSTANTIATE)	+= i2c-multi-instantiate.o

drivers/platform/x86/i2c-multi-instantiate.c

0 → 100644
+132 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0+

/*

 * I2C multi-instantiate driver, pseudo driver to instantiate multiple

 * i2c-clients from a single fwnode.

 *

 * Copyright 2018 Hans de Goede <hdegoede@redhat.com>

 */



#include <linux/acpi.h>

#include <linux/i2c.h>

#include <linux/interrupt.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/platform_device.h>



struct i2c_inst_data {

	const char *type;

	int gpio_irq_idx;

};



struct i2c_multi_inst_data {

	int num_clients;

	struct i2c_client *clients[0];

};



static int i2c_multi_inst_probe(struct platform_device *pdev)

{

	struct i2c_multi_inst_data *multi;

	const struct acpi_device_id *match;

	const struct i2c_inst_data *inst_data;

	struct i2c_board_info board_info = {};

	struct device *dev = &pdev->dev;

	struct acpi_device *adev;

	char name[32];

	int i, ret;



	match = acpi_match_device(dev->driver->acpi_match_table, dev);

	if (!match) {

		dev_err(dev, "Error ACPI match data is missing\n");

		return -ENODEV;

	}

	inst_data = (const struct i2c_inst_data *)match->driver_data;



	adev = ACPI_COMPANION(dev);



	/* Count number of clients to instantiate */

	for (i = 0; inst_data[i].type; i++) {}



	multi = devm_kmalloc(dev,

			offsetof(struct i2c_multi_inst_data, clients[i]),

			GFP_KERNEL);

	if (!multi)

		return -ENOMEM;



	multi->num_clients = i;



	for (i = 0; i < multi->num_clients; i++) {

		memset(&board_info, 0, sizeof(board_info));

		strlcpy(board_info.type, inst_data[i].type, I2C_NAME_SIZE);

		snprintf(name, sizeof(name), "%s-%s", match->id,

			 inst_data[i].type);

		board_info.dev_name = name;

		board_info.irq = 0;

		if (inst_data[i].gpio_irq_idx != -1) {

			ret = acpi_dev_gpio_irq_get(adev,

						    inst_data[i].gpio_irq_idx);

			if (ret < 0) {

				dev_err(dev, "Error requesting irq at index %d: %d\n",

					inst_data[i].gpio_irq_idx, ret);

				goto error;

			}

			board_info.irq = ret;

		}

		multi->clients[i] = i2c_acpi_new_device(dev, i, &board_info);

		if (!multi->clients[i]) {

			dev_err(dev, "Error creating i2c-client, idx %d\n", i);

			ret = -ENODEV;

			goto error;

		}

	}



	platform_set_drvdata(pdev, multi);

	return 0;



error:

	while (--i >= 0)

		i2c_unregister_device(multi->clients[i]);



	return ret;

}



static int i2c_multi_inst_remove(struct platform_device *pdev)

{

	struct i2c_multi_inst_data *multi = platform_get_drvdata(pdev);

	int i;



	for (i = 0; i < multi->num_clients; i++)

		i2c_unregister_device(multi->clients[i]);



	return 0;

}



static const struct i2c_inst_data bsg1160_data[]  = {

	{ "bmc150_accel", 0 },

	{ "bmc150_magn", -1 },

	{ "bmg160", -1 },

	{}

};



/*

 * Note new device-ids must also be added to i2c_multi_instantiate_ids in

 * drivers/acpi/scan.c: acpi_device_enumeration_by_parent().

 */

static const struct acpi_device_id i2c_multi_inst_acpi_ids[] = {

	{ "BSG1160", (unsigned long)bsg1160_data },

	{ }

};

MODULE_DEVICE_TABLE(acpi, i2c_multi_inst_acpi_ids);



static struct platform_driver i2c_multi_inst_driver = {

	.driver	= {

		.name = "I2C multi instantiate pseudo device driver",

		.acpi_match_table = ACPI_PTR(i2c_multi_inst_acpi_ids),

	},

	.probe = i2c_multi_inst_probe,

	.remove = i2c_multi_inst_remove,

};

module_platform_driver(i2c_multi_inst_driver);



MODULE_DESCRIPTION("I2C multi instantiate pseudo device driver");

MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");

MODULE_LICENSE("GPL");

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