/*
 * Copyright (C) ST-Ericsson SA 2010
 * Author: Mattias Nilsson <mattias.i.nilsson@stericsson.com> for ST Ericsson.
 * License terms: GNU General Public License (GPL) version 2
 */

#include <linux/err.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pm.h>
#include <linux/reboot.h>
#include <linux/signal.h>
#include <linux/power_supply.h>
#include <linux/mfd/abx500.h>
#include <linux/mfd/abx500/ab8500.h>
#include <linux/mfd/abx500/ab8500-sysctrl.h>

/* RtcCtrl bits */
#define AB8500_ALARM_MIN_LOW  0x08
#define AB8500_ALARM_MIN_MID 0x09
#define RTC_CTRL 0x0B
#define RTC_ALARM_ENABLE 0x4

static struct device *sysctrl_dev;

static void ab8500_power_off(void)
{
        sigset_t old;
        sigset_t all;
        static char *pss[] = {"ab8500_ac", "pm2301", "ab8500_usb"};
        int i;
        bool charger_present = false;
        union power_supply_propval val;
        struct power_supply *psy;
        int ret;

        if (sysctrl_dev == NULL) {
                pr_err("%s: sysctrl not initialized\n", __func__);
                return;
        }

        /*
         * If we have a charger connected and we're powering off,
         * reboot into charge-only mode.
         */

        for (i = 0; i < ARRAY_SIZE(pss); i++) {
                psy = power_supply_get_by_name(pss[i]);
                if (!psy)
                        continue;

                ret = psy->get_property(psy, POWER_SUPPLY_PROP_ONLINE, &val);

                if (!ret && val.intval) {
                        charger_present = true;
                        break;
                }
        }

        if (!charger_present)
                goto shutdown;

        /* Check if battery is known */
        psy = power_supply_get_by_name("ab8500_btemp");
        if (psy) {
                ret = psy->get_property(psy, POWER_SUPPLY_PROP_TECHNOLOGY,
                                        &val);
                if (!ret && val.intval != POWER_SUPPLY_TECHNOLOGY_UNKNOWN) {
                        printk(KERN_INFO
                               "Charger \"%s\" is connected with known battery."
                               " Rebooting.\n",
                               pss[i]);
                        machine_restart("charging");
                }
        }

shutdown:
        sigfillset(&all);

        if (!sigprocmask(SIG_BLOCK, &all, &old)) {
                (void)ab8500_sysctrl_set(AB8500_STW4500CTRL1,
                                         AB8500_STW4500CTRL1_SWOFF |
                                         AB8500_STW4500CTRL1_SWRESET4500N);
                (void)sigprocmask(SIG_SETMASK, &old, NULL);
        }
}

/*
 * Use the AB WD to reset the platform. It will perform a hard
 * reset instead of a soft reset. Write the reset reason to
 * the AB before reset, which can be read upon restart.
 */
void ab8500_restart(char mode, const char *cmd)
{
        struct ab8500_platform_data *plat;
        struct ab8500_sysctrl_platform_data *pdata;
        u16 reason = 0;
        u8 val;

        if (sysctrl_dev == NULL) {
                pr_err("%s: sysctrl not initialized\n", __func__);
                return;
        }

        plat = dev_get_platdata(sysctrl_dev->parent);
        pdata = plat->sysctrl;
        if (pdata && pdata->reboot_reason_code)
                reason = pdata->reboot_reason_code(cmd);
        else
                pr_warn("[%s] No reboot reason set. Default reason %d\n",
                        __func__, reason);

        /*
         * Disable RTC alarm, just a precaution so that no alarm
         * is running when WD reset is executed.
         */
        abx500_get_register_interruptible(sysctrl_dev, AB8500_RTC,
                RTC_CTRL , &val);
        abx500_set_register_interruptible(sysctrl_dev, AB8500_RTC,
                RTC_CTRL , (val & ~RTC_ALARM_ENABLE));

        /*
         * Android is not using the RTC alarm registers during reboot
         * so we borrow them for writing the reason of reset
         */

        /* reason[8 LSB] */
        val = reason & 0xFF;
        abx500_set_register_interruptible(sysctrl_dev, AB8500_RTC,
                AB8500_ALARM_MIN_LOW , val);

        /* reason[8 MSB] */
        val = (reason>>8) & 0xFF;
        abx500_set_register_interruptible(sysctrl_dev, AB8500_RTC,
                AB8500_ALARM_MIN_MID , val);

        /* Setting WD timeout to 0 */
        ab8500_sysctrl_write(AB8500_MAINWDOGTIMER, 0xFF, 0x0);

        /* Setting the parameters to AB8500 WD*/
        ab8500_sysctrl_write(AB8500_MAINWDOGCTRL, 0xFF, (AB8500_ENABLE_WD |
                AB8500_WD_RESTART_ON_EXPIRE | AB8500_KICK_WD));
}

static inline bool valid_bank(u8 bank)
{
        return ((bank == AB8500_SYS_CTRL1_BLOCK) ||
                (bank == AB8500_SYS_CTRL2_BLOCK));
}

int ab8500_sysctrl_read(u16 reg, u8 *value)
{
        u8 bank;

        if (sysctrl_dev == NULL)
                return -EINVAL;

        bank = (reg >> 8);
        if (!valid_bank(bank))
                return -EINVAL;

        return abx500_get_register_interruptible(sysctrl_dev, bank,
                (u8)(reg & 0xFF), value);
}
EXPORT_SYMBOL(ab8500_sysctrl_read);

int ab8500_sysctrl_write(u16 reg, u8 mask, u8 value)
{
        u8 bank;

        if (sysctrl_dev == NULL)
                return -EINVAL;

        bank = (reg >> 8);
        if (!valid_bank(bank))
                return -EINVAL;

        return abx500_mask_and_set_register_interruptible(sysctrl_dev, bank,
                (u8)(reg & 0xFF), mask, value);
}
EXPORT_SYMBOL(ab8500_sysctrl_write);

static int ab8500_sysctrl_probe(struct platform_device *pdev)
{
        struct ab8500 *ab8500 = dev_get_drvdata(pdev->dev.parent);
        struct ab8500_platform_data *plat;
        struct ab8500_sysctrl_platform_data *pdata;

        plat = dev_get_platdata(pdev->dev.parent);

        if (!plat)
                return -EINVAL;

        sysctrl_dev = &pdev->dev;

        if (!pm_power_off)
                pm_power_off = ab8500_power_off;

        pdata = plat->sysctrl;
        if (pdata) {
                int last, ret, i, j;

                if (is_ab8505(ab8500))
                        last = AB8500_SYSCLKREQ4RFCLKBUF;
                else
                        last = AB8500_SYSCLKREQ8RFCLKBUF;

                for (i = AB8500_SYSCLKREQ1RFCLKBUF; i <= last; i++) {
                        j = i - AB8500_SYSCLKREQ1RFCLKBUF;
                        ret = ab8500_sysctrl_write(i, 0xff,
                                        pdata->initial_req_buf_config[j]);
                        dev_dbg(&pdev->dev,
                                        "Setting SysClkReq%dRfClkBuf 0x%X\n",
                                        j + 1,
                                        pdata->initial_req_buf_config[j]);
                        if (ret < 0) {
                                dev_err(&pdev->dev,
                                        "unable to set sysClkReq%dRfClkBuf: "
                                        "%d\n", j + 1, ret);
                        }
                }
        }

        return 0;
}

static int ab8500_sysctrl_remove(struct platform_device *pdev)
{
        sysctrl_dev = NULL;

        if (pm_power_off == ab8500_power_off)
                pm_power_off = NULL;

        return 0;
}

static struct platform_driver ab8500_sysctrl_driver = {
        .driver = {
                .name = "ab8500-sysctrl",
                .owner = THIS_MODULE,
        },
        .probe = ab8500_sysctrl_probe,
        .remove = ab8500_sysctrl_remove,
};

static int __init ab8500_sysctrl_init(void)
{
        return platform_driver_register(&ab8500_sysctrl_driver);
}
arch_initcall(ab8500_sysctrl_init);

MODULE_AUTHOR("Mattias Nilsson <mattias.i.nilsson@stericsson.com");
MODULE_DESCRIPTION("AB8500 system control driver");
MODULE_LICENSE("GPL v2");