drivers/platform/chrome/chromeos_laptop.c - arm/linux - Git at Google

 /*
  *  chromeos_laptop.c - Driver to instantiate Chromebook i2c/smbus devices.
  *
  *  Author : Benson Leung <bleung@chromium.org>
  *
  *  Copyright (C) 2012 Google, Inc.
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
  *  the Free Software Foundation; either version 2 of the License, or
  *  (at your option) any later version.
  *
  *  This program is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *  GNU General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License
  *  along with this program; if not, write to the Free Software
  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  *
  */

 #include <linux/dmi.h>
 #include <linux/i2c.h>
 #include <linux/platform_data/atmel_mxt_ts.h>
 #include <linux/input.h>
 #include <linux/interrupt.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>

 #define ATMEL_TP_I2C_ADDR	0x4b
 #define ATMEL_TP_I2C_BL_ADDR	0x25
 #define ATMEL_TS_I2C_ADDR	0x4a
 #define ATMEL_TS_I2C_BL_ADDR	0x26
 #define CYAPA_TP_I2C_ADDR	0x67
 #define ELAN_TP_I2C_ADDR	0x15
 #define ISL_ALS_I2C_ADDR	0x44
 #define TAOS_ALS_I2C_ADDR	0x29

 #define MAX_I2C_DEVICE_DEFERRALS	5

 static struct i2c_client *als;
 static struct i2c_client *tp;
 static struct i2c_client *ts;

 static const char *i2c_adapter_names[] = {
 	"SMBus I801 adapter",
 	"i915 gmbus vga",
 	"i915 gmbus panel",
 	"Synopsys DesignWare I2C adapter",
 	"Synopsys DesignWare I2C adapter",
 };

 /* Keep this enum consistent with i2c_adapter_names */
 enum i2c_adapter_type {
 	I2C_ADAPTER_SMBUS = 0,
 	I2C_ADAPTER_VGADDC,
 	I2C_ADAPTER_PANEL,
 	I2C_ADAPTER_DESIGNWARE_0,
 	I2C_ADAPTER_DESIGNWARE_1,
 };

 enum i2c_peripheral_state {
 	UNPROBED = 0,
 	PROBED,
 	TIMEDOUT,
 };

 struct i2c_peripheral {
 	int (*add)(enum i2c_adapter_type type);
 	enum i2c_adapter_type type;
 	enum i2c_peripheral_state state;
 	int tries;
 };

 #define MAX_I2C_PERIPHERALS 4

 struct chromeos_laptop {
 	struct i2c_peripheral i2c_peripherals[MAX_I2C_PERIPHERALS];
 };

 static struct chromeos_laptop *cros_laptop;

 static struct i2c_board_info cyapa_device = {
 	I2C_BOARD_INFO("cyapa", CYAPA_TP_I2C_ADDR),
 	.flags		= I2C_CLIENT_WAKE,
 };

 static struct i2c_board_info elantech_device = {
 	I2C_BOARD_INFO("elan_i2c", ELAN_TP_I2C_ADDR),
 	.flags		= I2C_CLIENT_WAKE,
 };

 static struct i2c_board_info isl_als_device = {
 	I2C_BOARD_INFO("isl29018", ISL_ALS_I2C_ADDR),
 };

 static struct i2c_board_info tsl2583_als_device = {
 	I2C_BOARD_INFO("tsl2583", TAOS_ALS_I2C_ADDR),
 };

 static struct i2c_board_info tsl2563_als_device = {
 	I2C_BOARD_INFO("tsl2563", TAOS_ALS_I2C_ADDR),
 };

 static int mxt_t19_keys[] = {
 	KEY_RESERVED,
 	KEY_RESERVED,
 	KEY_RESERVED,
 	KEY_RESERVED,
 	KEY_RESERVED,
 	BTN_LEFT
 };

 static struct mxt_platform_data atmel_224s_tp_platform_data = {
 	.irqflags		= IRQF_TRIGGER_FALLING,
 	.t19_num_keys		= ARRAY_SIZE(mxt_t19_keys),
 	.t19_keymap		= mxt_t19_keys,
 	.suspend_mode		= MXT_SUSPEND_T9_CTRL,
 };

 static struct i2c_board_info atmel_224s_tp_device = {
 	I2C_BOARD_INFO("atmel_mxt_tp", ATMEL_TP_I2C_ADDR),
 	.platform_data = &atmel_224s_tp_platform_data,
 	.flags		= I2C_CLIENT_WAKE,
 };

 static struct mxt_platform_data atmel_1664s_platform_data = {
 	.irqflags		= IRQF_TRIGGER_FALLING,
 	.suspend_mode		= MXT_SUSPEND_T9_CTRL,
 };

 static struct i2c_board_info atmel_1664s_device = {
 	I2C_BOARD_INFO("atmel_mxt_ts", ATMEL_TS_I2C_ADDR),
 	.platform_data = &atmel_1664s_platform_data,
 	.flags		= I2C_CLIENT_WAKE,
 };

 static struct i2c_client *__add_probed_i2c_device(
 		const char *name,
 		int bus,
 		struct i2c_board_info *info,
 		const unsigned short *alt_addr_list)
 {
 	const struct dmi_device *dmi_dev;
 	const struct dmi_dev_onboard *dev_data;
 	struct i2c_adapter *adapter;
 	struct i2c_client *client = NULL;
 	const unsigned short addr_list[] = { info->addr, I2C_CLIENT_END };

 	if (bus < 0)
 		return NULL;
 	/*
 	 * If a name is specified, look for irq platform information stashed
 	 * in DMI_DEV_TYPE_DEV_ONBOARD by the Chrome OS custom system firmware.
 	 */
 	if (name) {
 		dmi_dev = dmi_find_device(DMI_DEV_TYPE_DEV_ONBOARD, name, NULL);
 		if (!dmi_dev) {
 			pr_err("%s failed to dmi find device %s.\n",
 			       __func__,
 			       name);
 			return NULL;
 		}
 		dev_data = (struct dmi_dev_onboard *)dmi_dev->device_data;
 		if (!dev_data) {
 			pr_err("%s failed to get data from dmi for %s.\n",
 			       __func__, name);
 			return NULL;
 		}
 		info->irq = dev_data->instance;
 	}

 	adapter = i2c_get_adapter(bus);
 	if (!adapter) {
 		pr_err("%s failed to get i2c adapter %d.\n", __func__, bus);
 		return NULL;
 	}

 	/*
 	 * Add the i2c device. If we can't detect it at the primary
 	 * address we scan secondary addresses. In any case the client
 	 * structure gets assigned primary address.
 	 */
 	client = i2c_new_probed_device(adapter, info, addr_list, NULL);
 	if (!client && alt_addr_list) {
 		struct i2c_board_info dummy_info = {
 			I2C_BOARD_INFO("dummy", info->addr),
 		};
 		struct i2c_client *dummy;

 		dummy = i2c_new_probed_device(adapter, &dummy_info,
 					      alt_addr_list, NULL);
 		if (dummy) {
 			pr_debug("%s %d-%02x is probed at %02x\n",
 				  __func__, bus, info->addr, dummy->addr);
 			i2c_unregister_device(dummy);
 			client = i2c_new_device(adapter, info);
 		}
 	}

 	if (!client)
 		pr_notice("%s failed to register device %d-%02x\n",
 			  __func__, bus, info->addr);
 	else
 		pr_debug("%s added i2c device %d-%02x\n",
 			 __func__, bus, info->addr);

 	i2c_put_adapter(adapter);
 	return client;
 }

 struct i2c_lookup {
 	const char *name;
 	int instance;
 	int n;
 };

 static int __find_i2c_adap(struct device *dev, void *data)
 {
 	struct i2c_lookup *lookup = data;
 	static const char *prefix = "i2c-";
 	struct i2c_adapter *adapter;

 	if (strncmp(dev_name(dev), prefix, strlen(prefix)) != 0)
 		return 0;
 	adapter = to_i2c_adapter(dev);
 	if (strncmp(adapter->name, lookup->name, strlen(lookup->name)) == 0 &&
 	    lookup->n++ == lookup->instance)
 		return 1;
 	return 0;
 }

 static int find_i2c_adapter_num(enum i2c_adapter_type type)
 {
 	struct device *dev = NULL;
 	struct i2c_adapter *adapter;
 	struct i2c_lookup lookup;

 	memset(&lookup, 0, sizeof(lookup));
 	lookup.name = i2c_adapter_names[type];
 	lookup.instance = (type == I2C_ADAPTER_DESIGNWARE_1) ? 1 : 0;

 	/* find the adapter by name */
 	dev = bus_find_device(&i2c_bus_type, NULL, &lookup, __find_i2c_adap);
 	if (!dev) {
 		/* Adapters may appear later. Deferred probing will retry */
 		pr_notice("%s: i2c adapter %s not found on system.\n", __func__,
 			  lookup.name);
 		return -ENODEV;
 	}
 	adapter = to_i2c_adapter(dev);
 	return adapter->nr;
 }

 /*
  * Takes a list of addresses in addrs as such :
  * { addr1, ... , addrn, I2C_CLIENT_END };
  * add_probed_i2c_device will use i2c_new_probed_device
  * and probe for devices at all of the addresses listed.
  * Returns NULL if no devices found.
  * See Documentation/i2c/instantiating-devices for more information.
  */
 static struct i2c_client *add_probed_i2c_device(
 		const char *name,
 		enum i2c_adapter_type type,
 		struct i2c_board_info *info,
 		const unsigned short *addrs)
 {
 	return __add_probed_i2c_device(name,
 				       find_i2c_adapter_num(type),
 				       info,
 				       addrs);
 }

 /*
  * Probes for a device at a single address, the one provided by
  * info->addr.
  * Returns NULL if no device found.
  */
 static struct i2c_client *add_i2c_device(const char *name,
 						enum i2c_adapter_type type,
 						struct i2c_board_info *info)
 {
 	return __add_probed_i2c_device(name,
 				       find_i2c_adapter_num(type),
 				       info,
 				       NULL);
 }

 static int setup_cyapa_tp(enum i2c_adapter_type type)
 {
 	if (tp)
 		return 0;

 	/* add cyapa touchpad */
 	tp = add_i2c_device("trackpad", type, &cyapa_device);
 	return (!tp) ? -EAGAIN : 0;
 }

 static int setup_atmel_224s_tp(enum i2c_adapter_type type)
 {
 	const unsigned short addr_list[] = { ATMEL_TP_I2C_BL_ADDR,
 					     I2C_CLIENT_END };
 	if (tp)
 		return 0;

 	/* add atmel mxt touchpad */
 	tp = add_probed_i2c_device("trackpad", type,
 				   &atmel_224s_tp_device, addr_list);
 	return (!tp) ? -EAGAIN : 0;
 }

 static int setup_elantech_tp(enum i2c_adapter_type type)
 {
 	if (tp)
 		return 0;

 	/* add elantech touchpad */
 	tp = add_i2c_device("trackpad", type, &elantech_device);
 	return (!tp) ? -EAGAIN : 0;
 }

 static int setup_atmel_1664s_ts(enum i2c_adapter_type type)
 {
 	const unsigned short addr_list[] = { ATMEL_TS_I2C_BL_ADDR,
 					     I2C_CLIENT_END };
 	if (ts)
 		return 0;

 	/* add atmel mxt touch device */
 	ts = add_probed_i2c_device("touchscreen", type,
 				   &atmel_1664s_device, addr_list);
 	return (!ts) ? -EAGAIN : 0;
 }

 static int setup_isl29018_als(enum i2c_adapter_type type)
 {
 	if (als)
 		return 0;

 	/* add isl29018 light sensor */
 	als = add_i2c_device("lightsensor", type, &isl_als_device);
 	return (!als) ? -EAGAIN : 0;
 }

 static int setup_tsl2583_als(enum i2c_adapter_type type)
 {
 	if (als)
 		return 0;

 	/* add tsl2583 light sensor */
 	als = add_i2c_device(NULL, type, &tsl2583_als_device);
 	return (!als) ? -EAGAIN : 0;
 }

 static int setup_tsl2563_als(enum i2c_adapter_type type)
 {
 	if (als)
 		return 0;

 	/* add tsl2563 light sensor */
 	als = add_i2c_device(NULL, type, &tsl2563_als_device);
 	return (!als) ? -EAGAIN : 0;
 }

 static int __init chromeos_laptop_dmi_matched(const struct dmi_system_id *id)
 {
 	cros_laptop = (void *)id->driver_data;
 	pr_debug("DMI Matched %s.\n", id->ident);

 	/* Indicate to dmi_scan that processing is done. */
 	return 1;
 }

 static int chromeos_laptop_probe(struct platform_device *pdev)
 {
 	int i;
 	int ret = 0;

 	for (i = 0; i < MAX_I2C_PERIPHERALS; i++) {
 		struct i2c_peripheral *i2c_dev;

 		i2c_dev = &cros_laptop->i2c_peripherals[i];

 		/* No more peripherals. */
 		if (i2c_dev->add == NULL)
 			break;

 		if (i2c_dev->state == TIMEDOUT || i2c_dev->state == PROBED)
 			continue;

 		/*
 		 * Check that the i2c adapter is present.
 		 * -EPROBE_DEFER if missing as the adapter may appear much
 		 * later.
 		 */
 		if (find_i2c_adapter_num(i2c_dev->type) == -ENODEV) {
 			ret = -EPROBE_DEFER;
 			continue;
 		}

 		/* Add the device. */
 		if (i2c_dev->add(i2c_dev->type) == -EAGAIN) {
 			/*
 			 * Set -EPROBE_DEFER a limited num of times
 			 * if device is not successfully added.
 			 */
 			if (++i2c_dev->tries < MAX_I2C_DEVICE_DEFERRALS) {
 				ret = -EPROBE_DEFER;
 			} else {
 				/* Ran out of tries. */
 				pr_notice("%s: Ran out of tries for device.\n",
 					  __func__);
 				i2c_dev->state = TIMEDOUT;
 			}
 		} else {
 			i2c_dev->state = PROBED;
 		}
 	}

 	return ret;
 }

 static struct chromeos_laptop samsung_series_5_550 = {
 	.i2c_peripherals = {
 		/* Touchpad. */
 		{ .add = setup_cyapa_tp, I2C_ADAPTER_SMBUS },
 		/* Light Sensor. */
 		{ .add = setup_isl29018_als, I2C_ADAPTER_SMBUS },
 	},
 };

 static struct chromeos_laptop samsung_series_5 = {
 	.i2c_peripherals = {
 		/* Light Sensor. */
 		{ .add = setup_tsl2583_als, I2C_ADAPTER_SMBUS },
 	},
 };

 static struct chromeos_laptop chromebook_pixel = {
 	.i2c_peripherals = {
 		/* Touch Screen. */
 		{ .add = setup_atmel_1664s_ts, I2C_ADAPTER_PANEL },
 		/* Touchpad. */
 		{ .add = setup_atmel_224s_tp, I2C_ADAPTER_VGADDC },
 		/* Light Sensor. */
 		{ .add = setup_isl29018_als, I2C_ADAPTER_PANEL },
 	},
 };

 static struct chromeos_laptop hp_chromebook_14 = {
 	.i2c_peripherals = {
 		/* Touchpad. */
 		{ .add = setup_cyapa_tp, I2C_ADAPTER_DESIGNWARE_0 },
 	},
 };

 static struct chromeos_laptop dell_chromebook_11 = {
 	.i2c_peripherals = {
 		/* Touchpad. */
 		{ .add = setup_cyapa_tp, I2C_ADAPTER_DESIGNWARE_0 },
 		/* Elan Touchpad option. */
 		{ .add = setup_elantech_tp, I2C_ADAPTER_DESIGNWARE_0 },
 	},
 };

 static struct chromeos_laptop toshiba_cb35 = {
 	.i2c_peripherals = {
 		/* Touchpad. */
 		{ .add = setup_cyapa_tp, I2C_ADAPTER_DESIGNWARE_0 },
 	},
 };

 static struct chromeos_laptop acer_c7_chromebook = {
 	.i2c_peripherals = {
 		/* Touchpad. */
 		{ .add = setup_cyapa_tp, I2C_ADAPTER_SMBUS },
 	},
 };

 static struct chromeos_laptop acer_ac700 = {
 	.i2c_peripherals = {
 		/* Light Sensor. */
 		{ .add = setup_tsl2563_als, I2C_ADAPTER_SMBUS },
 	},
 };

 static struct chromeos_laptop acer_c720 = {
 	.i2c_peripherals = {
 		/* Touchscreen. */
 		{ .add = setup_atmel_1664s_ts, I2C_ADAPTER_DESIGNWARE_1 },
 		/* Touchpad. */
 		{ .add = setup_cyapa_tp, I2C_ADAPTER_DESIGNWARE_0 },
 		/* Elan Touchpad option. */
 		{ .add = setup_elantech_tp, I2C_ADAPTER_DESIGNWARE_0 },
 		/* Light Sensor. */
 		{ .add = setup_isl29018_als, I2C_ADAPTER_DESIGNWARE_1 },
 	},
 };

 static struct chromeos_laptop hp_pavilion_14_chromebook = {
 	.i2c_peripherals = {
 		/* Touchpad. */
 		{ .add = setup_cyapa_tp, I2C_ADAPTER_SMBUS },
 	},
 };

 static struct chromeos_laptop cr48 = {
 	.i2c_peripherals = {
 		/* Light Sensor. */
 		{ .add = setup_tsl2563_als, I2C_ADAPTER_SMBUS },
 	},
 };

 #define _CBDD(board_) \
 	.callback = chromeos_laptop_dmi_matched, \
 	.driver_data = (void *)&board_

 static const struct dmi_system_id chromeos_laptop_dmi_table[] __initconst = {
 	{
 		.ident = "Samsung Series 5 550",
 		.matches = {
 			DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG"),
 			DMI_MATCH(DMI_PRODUCT_NAME, "Lumpy"),
 		},
 		_CBDD(samsung_series_5_550),
 	},
 	{
 		.ident = "Samsung Series 5",
 		.matches = {
 			DMI_MATCH(DMI_PRODUCT_NAME, "Alex"),
 		},
 		_CBDD(samsung_series_5),
 	},
 	{
 		.ident = "Chromebook Pixel",
 		.matches = {
 			DMI_MATCH(DMI_SYS_VENDOR, "GOOGLE"),
 			DMI_MATCH(DMI_PRODUCT_NAME, "Link"),
 		},
 		_CBDD(chromebook_pixel),
 	},
 	{
 		.ident = "Wolf",
 		.matches = {
 			DMI_MATCH(DMI_BIOS_VENDOR, "coreboot"),
 			DMI_MATCH(DMI_PRODUCT_NAME, "Wolf"),
 		},
 		_CBDD(dell_chromebook_11),
 	},
 	{
 		.ident = "HP Chromebook 14",
 		.matches = {
 			DMI_MATCH(DMI_BIOS_VENDOR, "coreboot"),
 			DMI_MATCH(DMI_PRODUCT_NAME, "Falco"),
 		},
 		_CBDD(hp_chromebook_14),
 	},
 	{
 		.ident = "Toshiba CB35",
 		.matches = {
 			DMI_MATCH(DMI_BIOS_VENDOR, "coreboot"),
 			DMI_MATCH(DMI_PRODUCT_NAME, "Leon"),
 		},
 		_CBDD(toshiba_cb35),
 	},
 	{
 		.ident = "Acer C7 Chromebook",
 		.matches = {
 			DMI_MATCH(DMI_PRODUCT_NAME, "Parrot"),
 		},
 		_CBDD(acer_c7_chromebook),
 	},
 	{
 		.ident = "Acer AC700",
 		.matches = {
 			DMI_MATCH(DMI_PRODUCT_NAME, "ZGB"),
 		},
 		_CBDD(acer_ac700),
 	},
 	{
 		.ident = "Acer C720",
 		.matches = {
 			DMI_MATCH(DMI_PRODUCT_NAME, "Peppy"),
 		},
 		_CBDD(acer_c720),
 	},
 	{
 		.ident = "HP Pavilion 14 Chromebook",
 		.matches = {
 			DMI_MATCH(DMI_PRODUCT_NAME, "Butterfly"),
 		},
 		_CBDD(hp_pavilion_14_chromebook),
 	},
 	{
 		.ident = "Cr-48",
 		.matches = {
 			DMI_MATCH(DMI_PRODUCT_NAME, "Mario"),
 		},
 		_CBDD(cr48),
 	},
 	{ }
 };
 MODULE_DEVICE_TABLE(dmi, chromeos_laptop_dmi_table);

 static struct platform_device *cros_platform_device;

 static struct platform_driver cros_platform_driver = {
 	.driver = {
 		.name = "chromeos_laptop",
 	},
 	.probe = chromeos_laptop_probe,
 };

 static int __init chromeos_laptop_init(void)
 {
 	int ret;

 	if (!dmi_check_system(chromeos_laptop_dmi_table)) {
 		pr_debug("%s unsupported system.\n", __func__);
 		return -ENODEV;
 	}

 	ret = platform_driver_register(&cros_platform_driver);
 	if (ret)
 		return ret;

 	cros_platform_device = platform_device_alloc("chromeos_laptop", -1);
 	if (!cros_platform_device) {
 		ret = -ENOMEM;
 		goto fail_platform_device1;
 	}

 	ret = platform_device_add(cros_platform_device);
 	if (ret)
 		goto fail_platform_device2;

 	return 0;

 fail_platform_device2:
 	platform_device_put(cros_platform_device);
 fail_platform_device1:
 	platform_driver_unregister(&cros_platform_driver);
 	return ret;
 }

 static void __exit chromeos_laptop_exit(void)
 {
 	if (als)
 		i2c_unregister_device(als);
 	if (tp)
 		i2c_unregister_device(tp);
 	if (ts)
 		i2c_unregister_device(ts);

 	platform_device_unregister(cros_platform_device);
 	platform_driver_unregister(&cros_platform_driver);
 }

 module_init(chromeos_laptop_init);
 module_exit(chromeos_laptop_exit);

 MODULE_DESCRIPTION("Chrome OS Laptop driver");
 MODULE_AUTHOR("Benson Leung <bleung@chromium.org>");
 MODULE_LICENSE("GPL");
	/*
	* chromeos_laptop.c - Driver to instantiate Chromebook i2c/smbus devices.
	*
	* Author : Benson Leung <bleung@chromium.org>
	*
	* Copyright (C) 2012 Google, Inc.
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	*
	*/

	#include <linux/dmi.h>
	#include <linux/i2c.h>
	#include <linux/platform_data/atmel_mxt_ts.h>
	#include <linux/input.h>
	#include <linux/interrupt.h>
	#include <linux/module.h>
	#include <linux/platform_device.h>

	#define ATMEL_TP_I2C_ADDR 0x4b
	#define ATMEL_TP_I2C_BL_ADDR 0x25
	#define ATMEL_TS_I2C_ADDR 0x4a
	#define ATMEL_TS_I2C_BL_ADDR 0x26
	#define CYAPA_TP_I2C_ADDR 0x67
	#define ELAN_TP_I2C_ADDR 0x15
	#define ISL_ALS_I2C_ADDR 0x44
	#define TAOS_ALS_I2C_ADDR 0x29

	#define MAX_I2C_DEVICE_DEFERRALS 5

	static struct i2c_client *als;
	static struct i2c_client *tp;
	static struct i2c_client *ts;

	static const char *i2c_adapter_names[] = {
	"SMBus I801 adapter",
	"i915 gmbus vga",
	"i915 gmbus panel",
	"Synopsys DesignWare I2C adapter",
	"Synopsys DesignWare I2C adapter",
	};

	/* Keep this enum consistent with i2c_adapter_names */
	enum i2c_adapter_type {
	I2C_ADAPTER_SMBUS = 0,
	I2C_ADAPTER_VGADDC,
	I2C_ADAPTER_PANEL,
	I2C_ADAPTER_DESIGNWARE_0,
	I2C_ADAPTER_DESIGNWARE_1,
	};

	enum i2c_peripheral_state {
	UNPROBED = 0,
	PROBED,
	TIMEDOUT,
	};

	struct i2c_peripheral {
	int (*add)(enum i2c_adapter_type type);
	enum i2c_adapter_type type;
	enum i2c_peripheral_state state;
	int tries;
	};

	#define MAX_I2C_PERIPHERALS 4

	struct chromeos_laptop {
	struct i2c_peripheral i2c_peripherals[MAX_I2C_PERIPHERALS];
	};

	static struct chromeos_laptop *cros_laptop;

	static struct i2c_board_info cyapa_device = {
	I2C_BOARD_INFO("cyapa", CYAPA_TP_I2C_ADDR),
	.flags = I2C_CLIENT_WAKE,
	};

	static struct i2c_board_info elantech_device = {
	I2C_BOARD_INFO("elan_i2c", ELAN_TP_I2C_ADDR),
	.flags = I2C_CLIENT_WAKE,
	};

	static struct i2c_board_info isl_als_device = {
	I2C_BOARD_INFO("isl29018", ISL_ALS_I2C_ADDR),
	};

	static struct i2c_board_info tsl2583_als_device = {
	I2C_BOARD_INFO("tsl2583", TAOS_ALS_I2C_ADDR),
	};

	static struct i2c_board_info tsl2563_als_device = {
	I2C_BOARD_INFO("tsl2563", TAOS_ALS_I2C_ADDR),
	};

	static int mxt_t19_keys[] = {
	KEY_RESERVED,
	KEY_RESERVED,
	KEY_RESERVED,
	KEY_RESERVED,
	KEY_RESERVED,
	BTN_LEFT
	};

	static struct mxt_platform_data atmel_224s_tp_platform_data = {
	.irqflags = IRQF_TRIGGER_FALLING,
	.t19_num_keys = ARRAY_SIZE(mxt_t19_keys),
	.t19_keymap = mxt_t19_keys,
	.suspend_mode = MXT_SUSPEND_T9_CTRL,
	};

	static struct i2c_board_info atmel_224s_tp_device = {
	I2C_BOARD_INFO("atmel_mxt_tp", ATMEL_TP_I2C_ADDR),
	.platform_data = &atmel_224s_tp_platform_data,
	.flags = I2C_CLIENT_WAKE,
	};

	static struct mxt_platform_data atmel_1664s_platform_data = {
	.irqflags = IRQF_TRIGGER_FALLING,
	.suspend_mode = MXT_SUSPEND_T9_CTRL,
	};

	static struct i2c_board_info atmel_1664s_device = {
	I2C_BOARD_INFO("atmel_mxt_ts", ATMEL_TS_I2C_ADDR),
	.platform_data = &atmel_1664s_platform_data,
	.flags = I2C_CLIENT_WAKE,
	};

	static struct i2c_client *__add_probed_i2c_device(
	const char *name,
	int bus,
	struct i2c_board_info *info,
	const unsigned short *alt_addr_list)
	{
	const struct dmi_device *dmi_dev;
	const struct dmi_dev_onboard *dev_data;
	struct i2c_adapter *adapter;
	struct i2c_client *client = NULL;
	const unsigned short addr_list[] = { info->addr, I2C_CLIENT_END };

	if (bus < 0)
	return NULL;
	/*
	* If a name is specified, look for irq platform information stashed
	* in DMI_DEV_TYPE_DEV_ONBOARD by the Chrome OS custom system firmware.
	*/
	if (name) {
	dmi_dev = dmi_find_device(DMI_DEV_TYPE_DEV_ONBOARD, name, NULL);
	if (!dmi_dev) {
	pr_err("%s failed to dmi find device %s.\n",
	__func__,
	name);
	return NULL;
	}
	dev_data = (struct dmi_dev_onboard *)dmi_dev->device_data;
	if (!dev_data) {
	pr_err("%s failed to get data from dmi for %s.\n",
	__func__, name);
	return NULL;
	}
	info->irq = dev_data->instance;
	}

	adapter = i2c_get_adapter(bus);
	if (!adapter) {
	pr_err("%s failed to get i2c adapter %d.\n", __func__, bus);
	return NULL;
	}

	/*
	* Add the i2c device. If we can't detect it at the primary
	* address we scan secondary addresses. In any case the client
	* structure gets assigned primary address.
	*/
	client = i2c_new_probed_device(adapter, info, addr_list, NULL);
	if (!client && alt_addr_list) {
	struct i2c_board_info dummy_info = {
	I2C_BOARD_INFO("dummy", info->addr),
	};
	struct i2c_client *dummy;

	dummy = i2c_new_probed_device(adapter, &dummy_info,
	alt_addr_list, NULL);
	if (dummy) {
	pr_debug("%s %d-%02x is probed at %02x\n",
	__func__, bus, info->addr, dummy->addr);
	i2c_unregister_device(dummy);
	client = i2c_new_device(adapter, info);
	}
	}

	if (!client)
	pr_notice("%s failed to register device %d-%02x\n",
	__func__, bus, info->addr);
	else
	pr_debug("%s added i2c device %d-%02x\n",
	__func__, bus, info->addr);

	i2c_put_adapter(adapter);
	return client;
	}

	struct i2c_lookup {
	const char *name;
	int instance;
	int n;
	};

	static int __find_i2c_adap(struct device dev, void data)
	{
	struct i2c_lookup *lookup = data;
	static const char *prefix = "i2c-";
	struct i2c_adapter *adapter;

	if (strncmp(dev_name(dev), prefix, strlen(prefix)) != 0)
	return 0;
	adapter = to_i2c_adapter(dev);
	if (strncmp(adapter->name, lookup->name, strlen(lookup->name)) == 0 &&
	lookup->n++ == lookup->instance)
	return 1;
	return 0;
	}

	static int find_i2c_adapter_num(enum i2c_adapter_type type)
	{
	struct device *dev = NULL;
	struct i2c_adapter *adapter;
	struct i2c_lookup lookup;

	memset(&lookup, 0, sizeof(lookup));
	lookup.name = i2c_adapter_names[type];
	lookup.instance = (type == I2C_ADAPTER_DESIGNWARE_1) ? 1 : 0;

	/* find the adapter by name */
	dev = bus_find_device(&i2c_bus_type, NULL, &lookup, __find_i2c_adap);
	if (!dev) {
	/* Adapters may appear later. Deferred probing will retry */
	pr_notice("%s: i2c adapter %s not found on system.\n", __func__,
	lookup.name);
	return -ENODEV;
	}
	adapter = to_i2c_adapter(dev);
	return adapter->nr;
	}

	/*
	* Takes a list of addresses in addrs as such :
	* { addr1, ... , addrn, I2C_CLIENT_END };
	* add_probed_i2c_device will use i2c_new_probed_device
	* and probe for devices at all of the addresses listed.
	* Returns NULL if no devices found.
	* See Documentation/i2c/instantiating-devices for more information.
	*/
	static struct i2c_client *add_probed_i2c_device(
	const char *name,
	enum i2c_adapter_type type,
	struct i2c_board_info *info,
	const unsigned short *addrs)
	{
	return __add_probed_i2c_device(name,
	find_i2c_adapter_num(type),
	info,
	addrs);
	}

	/*
	* Probes for a device at a single address, the one provided by
	* info->addr.
	* Returns NULL if no device found.
	*/
	static struct i2c_client add_i2c_device(const char name,
	enum i2c_adapter_type type,
	struct i2c_board_info *info)
	{
	return __add_probed_i2c_device(name,
	find_i2c_adapter_num(type),
	info,
	NULL);
	}

	static int setup_cyapa_tp(enum i2c_adapter_type type)
	{
	if (tp)
	return 0;

	/* add cyapa touchpad */
	tp = add_i2c_device("trackpad", type, &cyapa_device);
	return (!tp) ? -EAGAIN : 0;
	}

	static int setup_atmel_224s_tp(enum i2c_adapter_type type)
	{
	const unsigned short addr_list[] = { ATMEL_TP_I2C_BL_ADDR,
	I2C_CLIENT_END };
	if (tp)
	return 0;

	/* add atmel mxt touchpad */
	tp = add_probed_i2c_device("trackpad", type,
	&atmel_224s_tp_device, addr_list);
	return (!tp) ? -EAGAIN : 0;
	}

	static int setup_elantech_tp(enum i2c_adapter_type type)
	{
	if (tp)
	return 0;

	/* add elantech touchpad */
	tp = add_i2c_device("trackpad", type, &elantech_device);
	return (!tp) ? -EAGAIN : 0;
	}

	static int setup_atmel_1664s_ts(enum i2c_adapter_type type)
	{
	const unsigned short addr_list[] = { ATMEL_TS_I2C_BL_ADDR,
	I2C_CLIENT_END };
	if (ts)
	return 0;

	/* add atmel mxt touch device */
	ts = add_probed_i2c_device("touchscreen", type,
	&atmel_1664s_device, addr_list);
	return (!ts) ? -EAGAIN : 0;
	}

	static int setup_isl29018_als(enum i2c_adapter_type type)
	{
	if (als)
	return 0;

	/* add isl29018 light sensor */
	als = add_i2c_device("lightsensor", type, &isl_als_device);
	return (!als) ? -EAGAIN : 0;
	}

	static int setup_tsl2583_als(enum i2c_adapter_type type)
	{
	if (als)
	return 0;

	/* add tsl2583 light sensor */
	als = add_i2c_device(NULL, type, &tsl2583_als_device);
	return (!als) ? -EAGAIN : 0;
	}

	static int setup_tsl2563_als(enum i2c_adapter_type type)
	{
	if (als)
	return 0;

	/* add tsl2563 light sensor */
	als = add_i2c_device(NULL, type, &tsl2563_als_device);
	return (!als) ? -EAGAIN : 0;
	}

	static int __init chromeos_laptop_dmi_matched(const struct dmi_system_id *id)
	{
	cros_laptop = (void *)id->driver_data;
	pr_debug("DMI Matched %s.\n", id->ident);

	/* Indicate to dmi_scan that processing is done. */
	return 1;
	}

	static int chromeos_laptop_probe(struct platform_device *pdev)
	{
	int i;
	int ret = 0;

	for (i = 0; i < MAX_I2C_PERIPHERALS; i++) {
	struct i2c_peripheral *i2c_dev;

	i2c_dev = &cros_laptop->i2c_peripherals[i];

	/* No more peripherals. */
	if (i2c_dev->add == NULL)
	break;

	if (i2c_dev->state == TIMEDOUT \|\| i2c_dev->state == PROBED)
	continue;

	/*
	* Check that the i2c adapter is present.
	* -EPROBE_DEFER if missing as the adapter may appear much
	* later.
	*/
	if (find_i2c_adapter_num(i2c_dev->type) == -ENODEV) {
	ret = -EPROBE_DEFER;
	continue;
	}

	/* Add the device. */
	if (i2c_dev->add(i2c_dev->type) == -EAGAIN) {
	/*
	* Set -EPROBE_DEFER a limited num of times
	* if device is not successfully added.
	*/
	if (++i2c_dev->tries < MAX_I2C_DEVICE_DEFERRALS) {
	ret = -EPROBE_DEFER;
	} else {
	/* Ran out of tries. */
	pr_notice("%s: Ran out of tries for device.\n",
	__func__);
	i2c_dev->state = TIMEDOUT;
	}
	} else {
	i2c_dev->state = PROBED;
	}
	}

	return ret;
	}

	static struct chromeos_laptop samsung_series_5_550 = {
	.i2c_peripherals = {
	/* Touchpad. */
	{ .add = setup_cyapa_tp, I2C_ADAPTER_SMBUS },
	/* Light Sensor. */
	{ .add = setup_isl29018_als, I2C_ADAPTER_SMBUS },
	},
	};

	static struct chromeos_laptop samsung_series_5 = {
	.i2c_peripherals = {
	/* Light Sensor. */
	{ .add = setup_tsl2583_als, I2C_ADAPTER_SMBUS },
	},
	};

	static struct chromeos_laptop chromebook_pixel = {
	.i2c_peripherals = {
	/* Touch Screen. */
	{ .add = setup_atmel_1664s_ts, I2C_ADAPTER_PANEL },
	/* Touchpad. */
	{ .add = setup_atmel_224s_tp, I2C_ADAPTER_VGADDC },
	/* Light Sensor. */
	{ .add = setup_isl29018_als, I2C_ADAPTER_PANEL },
	},
	};

	static struct chromeos_laptop hp_chromebook_14 = {
	.i2c_peripherals = {
	/* Touchpad. */
	{ .add = setup_cyapa_tp, I2C_ADAPTER_DESIGNWARE_0 },
	},
	};

	static struct chromeos_laptop dell_chromebook_11 = {
	.i2c_peripherals = {
	/* Touchpad. */
	{ .add = setup_cyapa_tp, I2C_ADAPTER_DESIGNWARE_0 },
	/* Elan Touchpad option. */
	{ .add = setup_elantech_tp, I2C_ADAPTER_DESIGNWARE_0 },
	},
	};

	static struct chromeos_laptop toshiba_cb35 = {
	.i2c_peripherals = {
	/* Touchpad. */
	{ .add = setup_cyapa_tp, I2C_ADAPTER_DESIGNWARE_0 },
	},
	};

	static struct chromeos_laptop acer_c7_chromebook = {
	.i2c_peripherals = {
	/* Touchpad. */
	{ .add = setup_cyapa_tp, I2C_ADAPTER_SMBUS },
	},
	};

	static struct chromeos_laptop acer_ac700 = {
	.i2c_peripherals = {
	/* Light Sensor. */
	{ .add = setup_tsl2563_als, I2C_ADAPTER_SMBUS },
	},
	};

	static struct chromeos_laptop acer_c720 = {
	.i2c_peripherals = {
	/* Touchscreen. */
	{ .add = setup_atmel_1664s_ts, I2C_ADAPTER_DESIGNWARE_1 },
	/* Touchpad. */
	{ .add = setup_cyapa_tp, I2C_ADAPTER_DESIGNWARE_0 },
	/* Elan Touchpad option. */
	{ .add = setup_elantech_tp, I2C_ADAPTER_DESIGNWARE_0 },
	/* Light Sensor. */
	{ .add = setup_isl29018_als, I2C_ADAPTER_DESIGNWARE_1 },
	},
	};

	static struct chromeos_laptop hp_pavilion_14_chromebook = {
	.i2c_peripherals = {
	/* Touchpad. */
	{ .add = setup_cyapa_tp, I2C_ADAPTER_SMBUS },
	},
	};

	static struct chromeos_laptop cr48 = {
	.i2c_peripherals = {
	/* Light Sensor. */
	{ .add = setup_tsl2563_als, I2C_ADAPTER_SMBUS },
	},
	};

	#define _CBDD(board_) \
	.callback = chromeos_laptop_dmi_matched, \
	.driver_data = (void *)&board_

	static const struct dmi_system_id chromeos_laptop_dmi_table[] __initconst = {
	{
	.ident = "Samsung Series 5 550",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG"),
	DMI_MATCH(DMI_PRODUCT_NAME, "Lumpy"),
	},
	_CBDD(samsung_series_5_550),
	},
	{
	.ident = "Samsung Series 5",
	.matches = {
	DMI_MATCH(DMI_PRODUCT_NAME, "Alex"),
	},
	_CBDD(samsung_series_5),
	},
	{
	.ident = "Chromebook Pixel",
	.matches = {
	DMI_MATCH(DMI_SYS_VENDOR, "GOOGLE"),
	DMI_MATCH(DMI_PRODUCT_NAME, "Link"),
	},
	_CBDD(chromebook_pixel),
	},
	{
	.ident = "Wolf",
	.matches = {
	DMI_MATCH(DMI_BIOS_VENDOR, "coreboot"),
	DMI_MATCH(DMI_PRODUCT_NAME, "Wolf"),
	},
	_CBDD(dell_chromebook_11),
	},
	{
	.ident = "HP Chromebook 14",
	.matches = {
	DMI_MATCH(DMI_BIOS_VENDOR, "coreboot"),
	DMI_MATCH(DMI_PRODUCT_NAME, "Falco"),
	},
	_CBDD(hp_chromebook_14),
	},
	{
	.ident = "Toshiba CB35",
	.matches = {
	DMI_MATCH(DMI_BIOS_VENDOR, "coreboot"),
	DMI_MATCH(DMI_PRODUCT_NAME, "Leon"),
	},
	_CBDD(toshiba_cb35),
	},
	{
	.ident = "Acer C7 Chromebook",
	.matches = {
	DMI_MATCH(DMI_PRODUCT_NAME, "Parrot"),
	},
	_CBDD(acer_c7_chromebook),
	},
	{
	.ident = "Acer AC700",
	.matches = {
	DMI_MATCH(DMI_PRODUCT_NAME, "ZGB"),
	},
	_CBDD(acer_ac700),
	},
	{
	.ident = "Acer C720",
	.matches = {
	DMI_MATCH(DMI_PRODUCT_NAME, "Peppy"),
	},
	_CBDD(acer_c720),
	},
	{
	.ident = "HP Pavilion 14 Chromebook",
	.matches = {
	DMI_MATCH(DMI_PRODUCT_NAME, "Butterfly"),
	},
	_CBDD(hp_pavilion_14_chromebook),
	},
	{
	.ident = "Cr-48",
	.matches = {
	DMI_MATCH(DMI_PRODUCT_NAME, "Mario"),
	},
	_CBDD(cr48),
	},
	{ }
	};
	MODULE_DEVICE_TABLE(dmi, chromeos_laptop_dmi_table);

	static struct platform_device *cros_platform_device;

	static struct platform_driver cros_platform_driver = {
	.driver = {
	.name = "chromeos_laptop",
	},
	.probe = chromeos_laptop_probe,
	};

	static int __init chromeos_laptop_init(void)
	{
	int ret;

	if (!dmi_check_system(chromeos_laptop_dmi_table)) {
	pr_debug("%s unsupported system.\n", __func__);
	return -ENODEV;
	}

	ret = platform_driver_register(&cros_platform_driver);
	if (ret)
	return ret;

	cros_platform_device = platform_device_alloc("chromeos_laptop", -1);
	if (!cros_platform_device) {
	ret = -ENOMEM;
	goto fail_platform_device1;
	}

	ret = platform_device_add(cros_platform_device);
	if (ret)
	goto fail_platform_device2;

	return 0;

	fail_platform_device2:
	platform_device_put(cros_platform_device);
	fail_platform_device1:
	platform_driver_unregister(&cros_platform_driver);
	return ret;
	}

	static void __exit chromeos_laptop_exit(void)
	{
	if (als)
	i2c_unregister_device(als);
	if (tp)
	i2c_unregister_device(tp);
	if (ts)
	i2c_unregister_device(ts);

	platform_device_unregister(cros_platform_device);
	platform_driver_unregister(&cros_platform_driver);
	}

	module_init(chromeos_laptop_init);
	module_exit(chromeos_laptop_exit);

	MODULE_DESCRIPTION("Chrome OS Laptop driver");
	MODULE_AUTHOR("Benson Leung <bleung@chromium.org>");
	MODULE_LICENSE("GPL");