Platform: x86: Add Chrome OS Laptop driver

This adds the chromeos_laptop driver. It supports
the Cypress APA SMBUS touchpad as well as the isl29018 i2c ambient
light sensor on the Samsung Series 5 550 Chromebook.

Signed-off-by: Benson Leung <bleung@chromium.org>
Reviewed-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>

drivers/platform/x86/Kconfig

@@ -79,6 +79,17 @@ config ASUS_LAPTOP
 
 	  If you have an ACPI-compatible ASUS laptop, say Y or M here.
 
+config CHROMEOS_LAPTOP
+	tristate "Chrome OS Laptop"
+	depends on I2C
+	depends on DMI
+	---help---
+	  This driver instantiates i2c and smbus devices such as
+	  light sensors and touchpads.
+
+	  If you have a supported Chromebook, choose Y or M here.
+	  The module will be called chromeos_laptop.
+
 config DELL_LAPTOP
 	tristate "Dell Laptop Extras"
 	depends on X86

drivers/platform/x86/Makefile

@@ -50,3 +50,4 @@ obj-$(CONFIG_INTEL_MID_POWER_BUTTON)	+= intel_mid_powerbtn.o
 obj-$(CONFIG_INTEL_OAKTRAIL)	+= intel_oaktrail.o
 obj-$(CONFIG_SAMSUNG_Q10)	+= samsung-q10.o
 obj-$(CONFIG_APPLE_GMUX)	+= apple-gmux.o
+obj-$(CONFIG_CHROMEOS_LAPTOP)	+= chromeos_laptop.o

drivers/platform/x86/chromeos_laptop.c

@@ -0,0 +1,205 @@
+/*
+ *  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/module.h>
+
+#define CYAPA_TP_I2C_ADDR	0x67
+#define ISL_ALS_I2C_ADDR	0x44
+
+static struct i2c_client *als;
+static struct i2c_client *tp;
+
+const char *i2c_adapter_names[] = {
+	"SMBus I801 adapter",
+};
+
+/* Keep this enum consistent with i2c_adapter_names */
+enum i2c_adapter_type {
+	I2C_ADAPTER_SMBUS = 0,
+};
+
+static struct i2c_board_info __initdata cyapa_device = {
+	I2C_BOARD_INFO("cyapa", CYAPA_TP_I2C_ADDR),
+	.flags		= I2C_CLIENT_WAKE,
+};
+
+static struct i2c_board_info __initdata isl_als_device = {
+	I2C_BOARD_INFO("isl29018", ISL_ALS_I2C_ADDR),
+};
+
+static struct i2c_client __init *__add_probed_i2c_device(
+		const char *name,
+		int bus,
+		struct i2c_board_info *info,
+		const unsigned short *addrs)
+{
+	const struct dmi_device *dmi_dev;
+	const struct dmi_dev_onboard *dev_data;
+	struct i2c_adapter *adapter;
+	struct i2c_client *client;
+
+	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 */
+	client = i2c_new_probed_device(adapter, info, addrs, NULL);
+	if (!client)
+		pr_err("%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;
+}
+
+static int __init __find_i2c_adap(struct device *dev, void *data)
+{
+	const char *name = 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);
+	return (strncmp(adapter->name, name, strlen(name)) == 0);
+}
+
+static int __init find_i2c_adapter_num(enum i2c_adapter_type type)
+{
+	struct device *dev = NULL;
+	struct i2c_adapter *adapter;
+	const char *name = i2c_adapter_names[type];
+	/* find the adapter by name */
+	dev = bus_find_device(&i2c_bus_type, NULL, (void *)name,
+			      __find_i2c_adap);
+	if (!dev) {
+		pr_err("%s: i2c adapter %s not found on system.\n", __func__,
+		       name);
+		return -ENODEV;
+	}
+	adapter = to_i2c_adapter(dev);
+	return adapter->nr;
+}
+
+/*
+ * Probes for a device at a single address, the one provided by
+ * info->addr.
+ * Returns NULL if no device found.
+ */
+static struct i2c_client __init *add_smbus_device(const char *name,
+						  struct i2c_board_info *info)
+{
+	const unsigned short addr_list[] = { info->addr, I2C_CLIENT_END };
+	return __add_probed_i2c_device(name,
+				       find_i2c_adapter_num(I2C_ADAPTER_SMBUS),
+				       info,
+				       addr_list);
+}
+
+static int __init setup_lumpy_tp(const struct dmi_system_id *id)
+{
+	/* add cyapa touchpad on smbus */
+	tp = add_smbus_device("trackpad", &cyapa_device);
+	return 0;
+}
+
+static int __init setup_isl29018_als(const struct dmi_system_id *id)
+{
+	/* add isl29018 light sensor */
+	als = add_smbus_device("lightsensor", &isl_als_device);
+	return 0;
+}
+
+static struct dmi_system_id __initdata chromeos_laptop_dmi_table[] = {
+	{
+		.ident = "Samsung Series 5 550 - Touchpad",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "Lumpy"),
+		},
+		.callback = setup_lumpy_tp,
+	},
+	{
+		.ident = "Samsung Series 5 550 - Light Sensor",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "Lumpy"),
+		},
+		.callback = setup_isl29018_als,
+	},
+	{ }
+};
+MODULE_DEVICE_TABLE(dmi, chromeos_laptop_dmi_table);
+
+static int __init chromeos_laptop_init(void)
+{
+	if (!dmi_check_system(chromeos_laptop_dmi_table)) {
+		pr_debug("%s unsupported system.\n", __func__);
+		return -ENODEV;
+	}
+	return 0;
+}
+
+static void __exit chromeos_laptop_exit(void)
+{
+	if (als)
+		i2c_unregister_device(als);
+	if (tp)
+		i2c_unregister_device(tp);
+}
+
+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");