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>

3 files changed, 217 insertions, 0 deletions

diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 7ab0b2fba503..585db6fa64b8 100644
--- a/drivers/platform/x86/Kconfig
+++ b/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
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index bf7e4f935b17..ace2b38942fe 100644
--- a/drivers/platform/x86/Makefile
+++ b/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
diff --git a/drivers/platform/x86/chromeos_laptop.c b/drivers/platform/x86/chromeos_laptop.c
new file mode 100644
index 000000000000..a8329c3a9d0d
--- /dev/null
+++ b/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");