/*
 * intel_oaktrail.c - Intel OakTrail Platform support.
 *
 * Copyright (C) 2010-2011 Intel Corporation
 * Author: Yin Kangkai (kangkai.yin@intel.com)
 *
 * based on Compal driver, Copyright (C) 2008 Cezary Jackiewicz
 * <cezary.jackiewicz (at) gmail.com>, based on MSI driver
 * Copyright (C) 2006 Lennart Poettering <mzxreary (at) 0pointer (dot) de>
 *
 *  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., 51 Franklin Street, Fifth Floor, Boston, MA
 *  02110-1301, USA.
 *
 * This driver does below things:
 * 1. registers itself in the Linux backlight control in
 *    /sys/class/backlight/intel_oaktrail/
 *
 * 2. registers in the rfkill subsystem here: /sys/class/rfkill/rfkillX/
 *    for these components: wifi, bluetooth, wwan (3g), gps
 *
 * This driver might work on other products based on Oaktrail. If you
 * want to try it you can pass force=1 as argument to the module which
 * will force it to load even when the DMI data doesn't identify the
 * product as compatible.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/acpi.h>
#include <linux/fb.h>
#include <linux/mutex.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/backlight.h>
#include <linux/platform_device.h>
#include <linux/dmi.h>
#include <linux/rfkill.h>
#include <acpi/video.h>

#define DRIVER_NAME     "intel_oaktrail"
#define DRIVER_VERSION  "0.4ac1"

/*
 * This is the devices status address in EC space, and the control bits
 * definition:
 *
 * (1 << 0):    Camera enable/disable, RW.
 * (1 << 1):    Bluetooth enable/disable, RW.
 * (1 << 2):    GPS enable/disable, RW.
 * (1 << 3):    WiFi enable/disable, RW.
 * (1 << 4):    WWAN (3G) enable/disable, RW.
 * (1 << 5):    Touchscreen enable/disable, Read Only.
 */
#define OT_EC_DEVICE_STATE_ADDRESS      0xD6

#define OT_EC_CAMERA_MASK       (1 << 0)
#define OT_EC_BT_MASK           (1 << 1)
#define OT_EC_GPS_MASK          (1 << 2)
#define OT_EC_WIFI_MASK         (1 << 3)
#define OT_EC_WWAN_MASK         (1 << 4)
#define OT_EC_TS_MASK           (1 << 5)

/*
 * This is the address in EC space and commands used to control LCD backlight:
 *
 * Two steps needed to change the LCD backlight:
 *   1. write the backlight percentage into OT_EC_BL_BRIGHTNESS_ADDRESS;
 *   2. write OT_EC_BL_CONTROL_ON_DATA into OT_EC_BL_CONTROL_ADDRESS.
 *
 * To read the LCD back light, just read out the value from
 * OT_EC_BL_BRIGHTNESS_ADDRESS.
 *
 * LCD backlight brightness range: 0 - 100 (OT_EC_BL_BRIGHTNESS_MAX)
 */
#define OT_EC_BL_BRIGHTNESS_ADDRESS     0x44
#define OT_EC_BL_BRIGHTNESS_MAX         100
#define OT_EC_BL_CONTROL_ADDRESS        0x3A
#define OT_EC_BL_CONTROL_ON_DATA        0x1A


static bool force;
module_param(force, bool, 0);
MODULE_PARM_DESC(force, "Force driver load, ignore DMI data");

static struct platform_device *oaktrail_device;
static struct backlight_device *oaktrail_bl_device;
static struct rfkill *bt_rfkill;
static struct rfkill *gps_rfkill;
static struct rfkill *wifi_rfkill;
static struct rfkill *wwan_rfkill;


/* rfkill */
static int oaktrail_rfkill_set(void *data, bool blocked)
{
        u8 value;
        u8 result;
        unsigned long radio = (unsigned long) data;

        ec_read(OT_EC_DEVICE_STATE_ADDRESS, &result);

        if (!blocked)
                value = (u8) (result | radio);
        else
                value = (u8) (result & ~radio);

        ec_write(OT_EC_DEVICE_STATE_ADDRESS, value);

        return 0;
}

static const struct rfkill_ops oaktrail_rfkill_ops = {
        .set_block = oaktrail_rfkill_set,
};

static struct rfkill *oaktrail_rfkill_new(char *name, enum rfkill_type type,
                                          unsigned long mask)
{
        struct rfkill *rfkill_dev;
        u8 value;
        int err;

        rfkill_dev = rfkill_alloc(name, &oaktrail_device->dev, type,
                                  &oaktrail_rfkill_ops, (void *)mask);
        if (!rfkill_dev)
                return ERR_PTR(-ENOMEM);

        ec_read(OT_EC_DEVICE_STATE_ADDRESS, &value);
        rfkill_init_sw_state(rfkill_dev, (value & mask) != 1);

        err = rfkill_register(rfkill_dev);
        if (err) {
                rfkill_destroy(rfkill_dev);
                return ERR_PTR(err);
        }

        return rfkill_dev;
}

static inline void __oaktrail_rfkill_cleanup(struct rfkill *rf)
{
        if (rf) {
                rfkill_unregister(rf);
                rfkill_destroy(rf);
        }
}

static void oaktrail_rfkill_cleanup(void)
{
        __oaktrail_rfkill_cleanup(wifi_rfkill);
        __oaktrail_rfkill_cleanup(bt_rfkill);
        __oaktrail_rfkill_cleanup(gps_rfkill);
        __oaktrail_rfkill_cleanup(wwan_rfkill);
}

static int oaktrail_rfkill_init(void)
{
        int ret;

        wifi_rfkill = oaktrail_rfkill_new("oaktrail-wifi",
                                          RFKILL_TYPE_WLAN,
                                          OT_EC_WIFI_MASK);
        if (IS_ERR(wifi_rfkill)) {
                ret = PTR_ERR(wifi_rfkill);
                wifi_rfkill = NULL;
                goto cleanup;
        }

        bt_rfkill = oaktrail_rfkill_new("oaktrail-bluetooth",
                                        RFKILL_TYPE_BLUETOOTH,
                                        OT_EC_BT_MASK);
        if (IS_ERR(bt_rfkill)) {
                ret = PTR_ERR(bt_rfkill);
                bt_rfkill = NULL;
                goto cleanup;
        }

        gps_rfkill = oaktrail_rfkill_new("oaktrail-gps",
                                         RFKILL_TYPE_GPS,
                                         OT_EC_GPS_MASK);
        if (IS_ERR(gps_rfkill)) {
                ret = PTR_ERR(gps_rfkill);
                gps_rfkill = NULL;
                goto cleanup;
        }

        wwan_rfkill = oaktrail_rfkill_new("oaktrail-wwan",
                                          RFKILL_TYPE_WWAN,
                                          OT_EC_WWAN_MASK);
        if (IS_ERR(wwan_rfkill)) {
                ret = PTR_ERR(wwan_rfkill);
                wwan_rfkill = NULL;
                goto cleanup;
        }

        return 0;

cleanup:
        oaktrail_rfkill_cleanup();
        return ret;
}


/* backlight */
static int get_backlight_brightness(struct backlight_device *b)
{
        u8 value;
        ec_read(OT_EC_BL_BRIGHTNESS_ADDRESS, &value);

        return value;
}

static int set_backlight_brightness(struct backlight_device *b)
{
        u8 percent = (u8) b->props.brightness;
        if (percent < 0 || percent > OT_EC_BL_BRIGHTNESS_MAX)
                return -EINVAL;

        ec_write(OT_EC_BL_BRIGHTNESS_ADDRESS, percent);
        ec_write(OT_EC_BL_CONTROL_ADDRESS, OT_EC_BL_CONTROL_ON_DATA);

        return 0;
}

static const struct backlight_ops oaktrail_bl_ops = {
        .get_brightness = get_backlight_brightness,
        .update_status  = set_backlight_brightness,
};

static int oaktrail_backlight_init(void)
{
        struct backlight_device *bd;
        struct backlight_properties props;

        memset(&props, 0, sizeof(struct backlight_properties));
        props.type = BACKLIGHT_PLATFORM;
        props.max_brightness = OT_EC_BL_BRIGHTNESS_MAX;
        bd = backlight_device_register(DRIVER_NAME,
                                       &oaktrail_device->dev, NULL,
                                       &oaktrail_bl_ops,
                                       &props);

        if (IS_ERR(bd)) {
                oaktrail_bl_device = NULL;
                pr_warning("Unable to register backlight device\n");
                return PTR_ERR(bd);
        }

        oaktrail_bl_device = bd;

        bd->props.brightness = get_backlight_brightness(bd);
        bd->props.power = FB_BLANK_UNBLANK;
        backlight_update_status(bd);

        return 0;
}

static void oaktrail_backlight_exit(void)
{
        backlight_device_unregister(oaktrail_bl_device);
}

static int oaktrail_probe(struct platform_device *pdev)
{
        return 0;
}

static int oaktrail_remove(struct platform_device *pdev)
{
        return 0;
}

static struct platform_driver oaktrail_driver = {
        .driver = {
                .name = DRIVER_NAME,
        },
        .probe  = oaktrail_probe,
        .remove = oaktrail_remove,
};

static int dmi_check_cb(const struct dmi_system_id *id)
{
        pr_info("Identified model '%s'\n", id->ident);
        return 0;
}

static struct dmi_system_id __initdata oaktrail_dmi_table[] = {
        {
                .ident = "OakTrail platform",
                .matches = {
                        DMI_MATCH(DMI_PRODUCT_NAME, "OakTrail platform"),
                },
                .callback = dmi_check_cb
        },
        { }
};
MODULE_DEVICE_TABLE(dmi, oaktrail_dmi_table);

static int __init oaktrail_init(void)
{
        int ret;

        if (acpi_disabled) {
                pr_err("ACPI needs to be enabled for this driver to work!\n");
                return -ENODEV;
        }

        if (!force && !dmi_check_system(oaktrail_dmi_table)) {
                pr_err("Platform not recognized (You could try the module's force-parameter)");
                return -ENODEV;
        }

        ret = platform_driver_register(&oaktrail_driver);
        if (ret) {
                pr_warning("Unable to register platform driver\n");
                goto err_driver_reg;
        }

        oaktrail_device = platform_device_alloc(DRIVER_NAME, -1);
        if (!oaktrail_device) {
                pr_warning("Unable to allocate platform device\n");
                ret = -ENOMEM;
                goto err_device_alloc;
        }

        ret = platform_device_add(oaktrail_device);
        if (ret) {
                pr_warning("Unable to add platform device\n");
                goto err_device_add;
        }

        if (acpi_video_get_backlight_type() == acpi_backlight_vendor) {
                ret = oaktrail_backlight_init();
                if (ret)
                        goto err_backlight;
        }

        ret = oaktrail_rfkill_init();
        if (ret) {
                pr_warning("Setup rfkill failed\n");
                goto err_rfkill;
        }

        pr_info("Driver "DRIVER_VERSION" successfully loaded\n");
        return 0;

err_rfkill:
        oaktrail_backlight_exit();
err_backlight:
        platform_device_del(oaktrail_device);
err_device_add:
        platform_device_put(oaktrail_device);
err_device_alloc:
        platform_driver_unregister(&oaktrail_driver);
err_driver_reg:

        return ret;
}

static void __exit oaktrail_cleanup(void)
{
        oaktrail_backlight_exit();
        oaktrail_rfkill_cleanup();
        platform_device_unregister(oaktrail_device);
        platform_driver_unregister(&oaktrail_driver);

        pr_info("Driver unloaded\n");
}

module_init(oaktrail_init);
module_exit(oaktrail_cleanup);

MODULE_AUTHOR("Yin Kangkai (kangkai.yin@intel.com)");
MODULE_DESCRIPTION("Intel Oaktrail Platform ACPI Extras");
MODULE_VERSION(DRIVER_VERSION);
MODULE_LICENSE("GPL");