Commit 7b3d4f44 authored by Nick Crews's avatar Nick Crews Committed by Enric Balletbo i Serra
Browse files

platform/chrome: Add new driver for Wilco EC 



This EC is an incompatible variant of the typical Chrome OS embedded
controller.  It uses the same low-level communication and a similar
protocol with some significant differences.  The EC firmware does
not support the same mailbox commands so it is not registered as a
cros_ec device type.  This commit exports the wilco_ec_mailbox()
function so that other modules can use it to communicate with the EC.

Signed-off-by: default avatarDuncan Laurie <dlaurie@google.com>
Signed-off-by: default avatarNick Crews <ncrews@chromium.org>
[Fix the sparse warning: symbol 'wilco_ec_transfer' was not declared]
Signed-off-by: default avatarWei Yongjun <weiyongjun1@huawei.com>
[Fix Kconfig dependencies for wilco_ec]
Reported-by: default avatarRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: default avatarEnric Balletbo i Serra <enric.balletbo@collabora.com>
parent 6b7cb222

drivers/platform/chrome/Kconfig

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@@ -152,4 +152,6 @@ config CROS_EC_SYSFS 
	  To compile this driver as a module, choose M here: the

	  module will be called cros_ec_sysfs.



source "drivers/platform/chrome/wilco_ec/Kconfig"



endif # CHROMEOS_PLATFORMS

drivers/platform/chrome/Makefile

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@@ -14,3 +14,5 @@ obj-$(CONFIG_CROS_EC_LIGHTBAR) += cros_ec_lightbar.o 
obj-$(CONFIG_CROS_EC_VBC)		+= cros_ec_vbc.o

obj-$(CONFIG_CROS_EC_DEBUGFS)		+= cros_ec_debugfs.o

obj-$(CONFIG_CROS_EC_SYSFS)		+= cros_ec_sysfs.o



obj-$(CONFIG_WILCO_EC)			+= wilco_ec/

drivers/platform/chrome/wilco_ec/Kconfig

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config WILCO_EC

	tristate "ChromeOS Wilco Embedded Controller"

	depends on ACPI && X86 && CROS_EC_LPC_MEC

	help

	  If you say Y here, you get support for talking to the ChromeOS

	  Wilco EC over an eSPI bus. This uses a simple byte-level protocol

	  with a checksum.



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

	  module will be called wilco_ec.

drivers/platform/chrome/wilco_ec/Makefile

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# SPDX-License-Identifier: GPL-2.0



wilco_ec-objs				:= core.o mailbox.o

obj-$(CONFIG_WILCO_EC)			+= wilco_ec.o

drivers/platform/chrome/wilco_ec/core.c

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// SPDX-License-Identifier: GPL-2.0

/*

 * Core driver for Wilco Embedded Controller

 *

 * Copyright 2018 Google LLC

 *

 * This is the entry point for the drivers that control the Wilco EC.

 * This driver is responsible for several tasks:

 * - Initialize the register interface that is used by wilco_ec_mailbox()

 * - Create a platform device which is picked up by the debugfs driver

 * - Create a platform device which is picked up by the RTC driver

 */



#include <linux/acpi.h>

#include <linux/device.h>

#include <linux/ioport.h>

#include <linux/module.h>

#include <linux/platform_data/wilco-ec.h>

#include <linux/platform_device.h>



#include "../cros_ec_lpc_mec.h"



#define DRV_NAME "wilco-ec"



static struct resource *wilco_get_resource(struct platform_device *pdev,

					   int index)

{

	struct device *dev = &pdev->dev;

	struct resource *res;



	res = platform_get_resource(pdev, IORESOURCE_IO, index);

	if (!res) {

		dev_dbg(dev, "Couldn't find IO resource %d\n", index);

		return res;

	}



	return devm_request_region(dev, res->start, resource_size(res),

				   dev_name(dev));

}



static int wilco_ec_probe(struct platform_device *pdev)

{

	struct device *dev = &pdev->dev;

	struct wilco_ec_device *ec;



	ec = devm_kzalloc(dev, sizeof(*ec), GFP_KERNEL);

	if (!ec)

		return -ENOMEM;



	platform_set_drvdata(pdev, ec);

	ec->dev = dev;

	mutex_init(&ec->mailbox_lock);



	/* Largest data buffer size requirement is extended data response */

	ec->data_size = sizeof(struct wilco_ec_response) +

		EC_MAILBOX_DATA_SIZE_EXTENDED;

	ec->data_buffer = devm_kzalloc(dev, ec->data_size, GFP_KERNEL);

	if (!ec->data_buffer)

		return -ENOMEM;



	/* Prepare access to IO regions provided by ACPI */

	ec->io_data = wilco_get_resource(pdev, 0);	/* Host Data */

	ec->io_command = wilco_get_resource(pdev, 1);	/* Host Command */

	ec->io_packet = wilco_get_resource(pdev, 2);	/* MEC EMI */

	if (!ec->io_data || !ec->io_command || !ec->io_packet)

		return -ENODEV;



	/* Initialize cros_ec register interface for communication */

	cros_ec_lpc_mec_init(ec->io_packet->start,

			     ec->io_packet->start + EC_MAILBOX_DATA_SIZE);



	return 0;

}



static int wilco_ec_remove(struct platform_device *pdev)

{

	/* Teardown cros_ec interface */

	cros_ec_lpc_mec_destroy();



	return 0;

}



static const struct acpi_device_id wilco_ec_acpi_device_ids[] = {

	{ "GOOG000C", 0 },

	{ }

};

MODULE_DEVICE_TABLE(acpi, wilco_ec_acpi_device_ids);



static struct platform_driver wilco_ec_driver = {

	.driver = {

		.name = DRV_NAME,

		.acpi_match_table = wilco_ec_acpi_device_ids,

	},

	.probe = wilco_ec_probe,

	.remove = wilco_ec_remove,

};



module_platform_driver(wilco_ec_driver);



MODULE_AUTHOR("Nick Crews <ncrews@chromium.org>");

MODULE_AUTHOR("Duncan Laurie <dlaurie@chromium.org>");

MODULE_LICENSE("GPL v2");

MODULE_DESCRIPTION("ChromeOS Wilco Embedded Controller driver");

MODULE_ALIAS("platform:" DRV_NAME);

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