/*
 * Support for OLPC XO-1 System Control Interrupts (SCI)
 *
 * Copyright (C) 2010 One Laptop per Child
 * Copyright (C) 2006 Red Hat, Inc.
 * Copyright (C) 2006 Advanced Micro Devices, 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.
 */

#include <linux/cs5535.h>
#include <linux/device.h>
#include <linux/gpio.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/pm.h>
#include <linux/pm_wakeup.h>
#include <linux/mfd/core.h>
#include <linux/power_supply.h>
#include <linux/suspend.h>
#include <linux/workqueue.h>
#include <linux/olpc-ec.h>

#include <asm/io.h>
#include <asm/msr.h>
#include <asm/olpc.h>

#define DRV_NAME        "olpc-xo1-sci"
#define PFX             DRV_NAME ": "

static unsigned long acpi_base;
static struct input_dev *power_button_idev;
static struct input_dev *ebook_switch_idev;
static struct input_dev *lid_switch_idev;

static int sci_irq;

static bool lid_open;
static bool lid_inverted;
static int lid_wake_mode;

enum lid_wake_modes {
        LID_WAKE_ALWAYS,
        LID_WAKE_OPEN,
        LID_WAKE_CLOSE,
};

static const char * const lid_wake_mode_names[] = {
        [LID_WAKE_ALWAYS] = "always",
        [LID_WAKE_OPEN] = "open",
        [LID_WAKE_CLOSE] = "close",
};

static void battery_status_changed(void)
{
        struct power_supply *psy = power_supply_get_by_name("olpc-battery");

        if (psy) {
                power_supply_changed(psy);
                put_device(psy->dev);
        }
}

static void ac_status_changed(void)
{
        struct power_supply *psy = power_supply_get_by_name("olpc-ac");

        if (psy) {
                power_supply_changed(psy);
                put_device(psy->dev);
        }
}

/* Report current ebook switch state through input layer */
static void send_ebook_state(void)
{
        unsigned char state;

        if (olpc_ec_cmd(EC_READ_EB_MODE, NULL, 0, &state, 1)) {
                pr_err(PFX "failed to get ebook state\n");
                return;
        }

        if (!!test_bit(SW_TABLET_MODE, ebook_switch_idev->sw) == state)
                return; /* Nothing new to report. */

        input_report_switch(ebook_switch_idev, SW_TABLET_MODE, state);
        input_sync(ebook_switch_idev);
        pm_wakeup_event(&ebook_switch_idev->dev, 0);
}

static void flip_lid_inverter(void)
{
        /* gpio is high; invert so we'll get l->h event interrupt */
        if (lid_inverted)
                cs5535_gpio_clear(OLPC_GPIO_LID, GPIO_INPUT_INVERT);
        else
                cs5535_gpio_set(OLPC_GPIO_LID, GPIO_INPUT_INVERT);
        lid_inverted = !lid_inverted;
}

static void detect_lid_state(void)
{
        /*
         * the edge detector hookup on the gpio inputs on the geode is
         * odd, to say the least.  See http://dev.laptop.org/ticket/5703
         * for details, but in a nutshell:  we don't use the edge
         * detectors.  instead, we make use of an anomoly:  with the both
         * edge detectors turned off, we still get an edge event on a
         * positive edge transition.  to take advantage of this, we use the
         * front-end inverter to ensure that that's the edge we're always
         * going to see next.
         */

        int state;

        state = cs5535_gpio_isset(OLPC_GPIO_LID, GPIO_READ_BACK);
        lid_open = !state ^ !lid_inverted; /* x ^^ y */
        if (!state)
                return;

        flip_lid_inverter();
}

/* Report current lid switch state through input layer */
static void send_lid_state(void)
{
        if (!!test_bit(SW_LID, lid_switch_idev->sw) == !lid_open)
                return; /* Nothing new to report. */

        input_report_switch(lid_switch_idev, SW_LID, !lid_open);
        input_sync(lid_switch_idev);
        pm_wakeup_event(&lid_switch_idev->dev, 0);
}

static ssize_t lid_wake_mode_show(struct device *dev,
                                  struct device_attribute *attr, char *buf)
{
        const char *mode = lid_wake_mode_names[lid_wake_mode];
        return sprintf(buf, "%s\n", mode);
}
static ssize_t lid_wake_mode_set(struct device *dev,
                                 struct device_attribute *attr,
                                 const char *buf, size_t count)
{
        int i;
        for (i = 0; i < ARRAY_SIZE(lid_wake_mode_names); i++) {
                const char *mode = lid_wake_mode_names[i];
                if (strlen(mode) != count || strncasecmp(mode, buf, count))
                        continue;

                lid_wake_mode = i;
                return count;
        }
        return -EINVAL;
}
static DEVICE_ATTR(lid_wake_mode, S_IWUSR | S_IRUGO, lid_wake_mode_show,
                   lid_wake_mode_set);

/*
 * Process all items in the EC's SCI queue.
 *
 * This is handled in a workqueue because olpc_ec_cmd can be slow (and
 * can even timeout).
 *
 * If propagate_events is false, the queue is drained without events being
 * generated for the interrupts.
 */
static void process_sci_queue(bool propagate_events)
{
        int r;
        u16 data;

        do {
                r = olpc_ec_sci_query(&data);
                if (r || !data)
                        break;

                pr_debug(PFX "SCI 0x%x received\n", data);

                switch (data) {
                case EC_SCI_SRC_BATERR:
                case EC_SCI_SRC_BATSOC:
                case EC_SCI_SRC_BATTERY:
                case EC_SCI_SRC_BATCRIT:
                        battery_status_changed();
                        break;
                case EC_SCI_SRC_ACPWR:
                        ac_status_changed();
                        break;
                }

                if (data == EC_SCI_SRC_EBOOK && propagate_events)
                        send_ebook_state();
        } while (data);

        if (r)
                pr_err(PFX "Failed to clear SCI queue");
}

static void process_sci_queue_work(struct work_struct *work)
{
        process_sci_queue(true);
}

static DECLARE_WORK(sci_work, process_sci_queue_work);

static irqreturn_t xo1_sci_intr(int irq, void *dev_id)
{
        struct platform_device *pdev = dev_id;
        u32 sts;
        u32 gpe;

        sts = inl(acpi_base + CS5536_PM1_STS);
        outl(sts | 0xffff, acpi_base + CS5536_PM1_STS);

        gpe = inl(acpi_base + CS5536_PM_GPE0_STS);
        outl(0xffffffff, acpi_base + CS5536_PM_GPE0_STS);

        dev_dbg(&pdev->dev, "sts %x gpe %x\n", sts, gpe);

        if (sts & CS5536_PWRBTN_FLAG) {
                if (!(sts & CS5536_WAK_FLAG)) {
                        /* Only report power button input when it was pressed
                         * during regular operation (as opposed to when it
                         * was used to wake the system). */
                        input_report_key(power_button_idev, KEY_POWER, 1);
                        input_sync(power_button_idev);
                        input_report_key(power_button_idev, KEY_POWER, 0);
                        input_sync(power_button_idev);
                }
                /* Report the wakeup event in all cases. */
                pm_wakeup_event(&power_button_idev->dev, 0);
        }

        if ((sts & (CS5536_RTC_FLAG | CS5536_WAK_FLAG)) ==
                        (CS5536_RTC_FLAG | CS5536_WAK_FLAG)) {
                /* When the system is woken by the RTC alarm, report the
                 * event on the rtc device. */
                struct device *rtc = bus_find_device_by_name(
                        &platform_bus_type, NULL, "rtc_cmos");
                if (rtc) {
                        pm_wakeup_event(rtc, 0);
                        put_device(rtc);
                }
        }

        if (gpe & CS5536_GPIOM7_PME_FLAG) { /* EC GPIO */
                cs5535_gpio_set(OLPC_GPIO_ECSCI, GPIO_NEGATIVE_EDGE_STS);
                schedule_work(&sci_work);
        }

        cs5535_gpio_set(OLPC_GPIO_LID, GPIO_NEGATIVE_EDGE_STS);
        cs5535_gpio_set(OLPC_GPIO_LID, GPIO_POSITIVE_EDGE_STS);
        detect_lid_state();
        send_lid_state();

        return IRQ_HANDLED;
}

static int xo1_sci_suspend(struct platform_device *pdev, pm_message_t state)
{
        if (device_may_wakeup(&power_button_idev->dev))
                olpc_xo1_pm_wakeup_set(CS5536_PM_PWRBTN);
        else
                olpc_xo1_pm_wakeup_clear(CS5536_PM_PWRBTN);

        if (device_may_wakeup(&ebook_switch_idev->dev))
                olpc_ec_wakeup_set(EC_SCI_SRC_EBOOK);
        else
                olpc_ec_wakeup_clear(EC_SCI_SRC_EBOOK);

        if (!device_may_wakeup(&lid_switch_idev->dev)) {
                cs5535_gpio_clear(OLPC_GPIO_LID, GPIO_EVENTS_ENABLE);
        } else if ((lid_open && lid_wake_mode == LID_WAKE_OPEN) ||
                   (!lid_open && lid_wake_mode == LID_WAKE_CLOSE)) {
                flip_lid_inverter();

                /* we may have just caused an event */
                cs5535_gpio_set(OLPC_GPIO_LID, GPIO_NEGATIVE_EDGE_STS);
                cs5535_gpio_set(OLPC_GPIO_LID, GPIO_POSITIVE_EDGE_STS);

                cs5535_gpio_set(OLPC_GPIO_LID, GPIO_EVENTS_ENABLE);
        }

        return 0;
}

static int xo1_sci_resume(struct platform_device *pdev)
{
        /*
         * We don't know what may have happened while we were asleep.
         * Reestablish our lid setup so we're sure to catch all transitions.
         */
        detect_lid_state();
        send_lid_state();
        cs5535_gpio_set(OLPC_GPIO_LID, GPIO_EVENTS_ENABLE);

        /* Enable all EC events */
        olpc_ec_mask_write(EC_SCI_SRC_ALL);

        /* Power/battery status might have changed too */
        battery_status_changed();
        ac_status_changed();
        return 0;
}

static int setup_sci_interrupt(struct platform_device *pdev)
{
        u32 lo, hi;
        u32 sts;
        int r;

        rdmsr(0x51400020, lo, hi);
        sci_irq = (lo >> 20) & 15;

        if (sci_irq) {
                dev_info(&pdev->dev, "SCI is mapped to IRQ %d\n", sci_irq);
        } else {
                /* Zero means masked */
                dev_info(&pdev->dev, "SCI unmapped. Mapping to IRQ 3\n");
                sci_irq = 3;
                lo |= 0x00300000;
                wrmsrl(0x51400020, lo);
        }

        /* Select level triggered in PIC */
        if (sci_irq < 8) {
                lo = inb(CS5536_PIC_INT_SEL1);
                lo |= 1 << sci_irq;
                outb(lo, CS5536_PIC_INT_SEL1);
        } else {
                lo = inb(CS5536_PIC_INT_SEL2);
                lo |= 1 << (sci_irq - 8);
                outb(lo, CS5536_PIC_INT_SEL2);
        }

        /* Enable interesting SCI events, and clear pending interrupts */
        sts = inl(acpi_base + CS5536_PM1_STS);
        outl(((CS5536_PM_PWRBTN | CS5536_PM_RTC) << 16) | 0xffff,
             acpi_base + CS5536_PM1_STS);

        r = request_irq(sci_irq, xo1_sci_intr, 0, DRV_NAME, pdev);
        if (r)
                dev_err(&pdev->dev, "can't request interrupt\n");

        return r;
}

static int setup_ec_sci(void)
{
        int r;

        r = gpio_request(OLPC_GPIO_ECSCI, "OLPC-ECSCI");
        if (r)
                return r;

        gpio_direction_input(OLPC_GPIO_ECSCI);

        /* Clear pending EC SCI events */
        cs5535_gpio_set(OLPC_GPIO_ECSCI, GPIO_NEGATIVE_EDGE_STS);
        cs5535_gpio_set(OLPC_GPIO_ECSCI, GPIO_POSITIVE_EDGE_STS);

        /*
         * Enable EC SCI events, and map them to both a PME and the SCI
         * interrupt.
         *
         * Ordinarily, in addition to functioning as GPIOs, Geode GPIOs can
         * be mapped to regular interrupts *or* Geode-specific Power
         * Management Events (PMEs) - events that bring the system out of
         * suspend. In this case, we want both of those things - the system
         * wakeup, *and* the ability to get an interrupt when an event occurs.
         *
         * To achieve this, we map the GPIO to a PME, and then we use one
         * of the many generic knobs on the CS5535 PIC to additionally map the
         * PME to the regular SCI interrupt line.
         */
        cs5535_gpio_set(OLPC_GPIO_ECSCI, GPIO_EVENTS_ENABLE);

        /* Set the SCI to cause a PME event on group 7 */
        cs5535_gpio_setup_event(OLPC_GPIO_ECSCI, 7, 1);

        /* And have group 7 also fire the SCI interrupt */
        cs5535_pic_unreqz_select_high(7, sci_irq);

        return 0;
}

static void free_ec_sci(void)
{
        gpio_free(OLPC_GPIO_ECSCI);
}

static int setup_lid_events(void)
{
        int r;

        r = gpio_request(OLPC_GPIO_LID, "OLPC-LID");
        if (r)
                return r;

        gpio_direction_input(OLPC_GPIO_LID);

        cs5535_gpio_clear(OLPC_GPIO_LID, GPIO_INPUT_INVERT);
        lid_inverted = 0;

        /* Clear edge detection and event enable for now */
        cs5535_gpio_clear(OLPC_GPIO_LID, GPIO_EVENTS_ENABLE);
        cs5535_gpio_clear(OLPC_GPIO_LID, GPIO_NEGATIVE_EDGE_EN);
        cs5535_gpio_clear(OLPC_GPIO_LID, GPIO_POSITIVE_EDGE_EN);
        cs5535_gpio_set(OLPC_GPIO_LID, GPIO_NEGATIVE_EDGE_STS);
        cs5535_gpio_set(OLPC_GPIO_LID, GPIO_POSITIVE_EDGE_STS);

        /* Set the LID to cause an PME event on group 6 */
        cs5535_gpio_setup_event(OLPC_GPIO_LID, 6, 1);

        /* Set PME group 6 to fire the SCI interrupt */
        cs5535_gpio_set_irq(6, sci_irq);

        /* Enable the event */
        cs5535_gpio_set(OLPC_GPIO_LID, GPIO_EVENTS_ENABLE);

        return 0;
}

static void free_lid_events(void)
{
        gpio_free(OLPC_GPIO_LID);
}

static int setup_power_button(struct platform_device *pdev)
{
        int r;

        power_button_idev = input_allocate_device();
        if (!power_button_idev)
                return -ENOMEM;

        power_button_idev->name = "Power Button";
        power_button_idev->phys = DRV_NAME "/input0";
        set_bit(EV_KEY, power_button_idev->evbit);
        set_bit(KEY_POWER, power_button_idev->keybit);

        power_button_idev->dev.parent = &pdev->dev;
        device_init_wakeup(&power_button_idev->dev, 1);

        r = input_register_device(power_button_idev);
        if (r) {
                dev_err(&pdev->dev, "failed to register power button: %d\n", r);
                input_free_device(power_button_idev);
        }

        return r;
}

static void free_power_button(void)
{
        input_unregister_device(power_button_idev);
}

static int setup_ebook_switch(struct platform_device *pdev)
{
        int r;

        ebook_switch_idev = input_allocate_device();
        if (!ebook_switch_idev)
                return -ENOMEM;

        ebook_switch_idev->name = "EBook Switch";
        ebook_switch_idev->phys = DRV_NAME "/input1";
        set_bit(EV_SW, ebook_switch_idev->evbit);
        set_bit(SW_TABLET_MODE, ebook_switch_idev->swbit);

        ebook_switch_idev->dev.parent = &pdev->dev;
        device_set_wakeup_capable(&ebook_switch_idev->dev, true);

        r = input_register_device(ebook_switch_idev);
        if (r) {
                dev_err(&pdev->dev, "failed to register ebook switch: %d\n", r);
                input_free_device(ebook_switch_idev);
        }

        return r;
}

static void free_ebook_switch(void)
{
        input_unregister_device(ebook_switch_idev);
}

static int setup_lid_switch(struct platform_device *pdev)
{
        int r;

        lid_switch_idev = input_allocate_device();
        if (!lid_switch_idev)
                return -ENOMEM;

        lid_switch_idev->name = "Lid Switch";
        lid_switch_idev->phys = DRV_NAME "/input2";
        set_bit(EV_SW, lid_switch_idev->evbit);
        set_bit(SW_LID, lid_switch_idev->swbit);

        lid_switch_idev->dev.parent = &pdev->dev;
        device_set_wakeup_capable(&lid_switch_idev->dev, true);

        r = input_register_device(lid_switch_idev);
        if (r) {
                dev_err(&pdev->dev, "failed to register lid switch: %d\n", r);
                goto err_register;
        }

        r = device_create_file(&lid_switch_idev->dev, &dev_attr_lid_wake_mode);
        if (r) {
                dev_err(&pdev->dev, "failed to create wake mode attr: %d\n", r);
                goto err_create_attr;
        }

        return 0;

err_create_attr:
        input_unregister_device(lid_switch_idev);
        lid_switch_idev = NULL;
err_register:
        input_free_device(lid_switch_idev);
        return r;
}

static void free_lid_switch(void)
{
        device_remove_file(&lid_switch_idev->dev, &dev_attr_lid_wake_mode);
        input_unregister_device(lid_switch_idev);
}

static int xo1_sci_probe(struct platform_device *pdev)
{
        struct resource *res;
        int r;

        /* don't run on non-XOs */
        if (!machine_is_olpc())
                return -ENODEV;

        r = mfd_cell_enable(pdev);
        if (r)
                return r;

        res = platform_get_resource(pdev, IORESOURCE_IO, 0);
        if (!res) {
                dev_err(&pdev->dev, "can't fetch device resource info\n");
                return -EIO;
        }
        acpi_base = res->start;

        r = setup_power_button(pdev);
        if (r)
                return r;

        r = setup_ebook_switch(pdev);
        if (r)
                goto err_ebook;

        r = setup_lid_switch(pdev);
        if (r)
                goto err_lid;

        r = setup_lid_events();
        if (r)
                goto err_lidevt;

        r = setup_ec_sci();
        if (r)
                goto err_ecsci;

        /* Enable PME generation for EC-generated events */
        outl(CS5536_GPIOM6_PME_EN | CS5536_GPIOM7_PME_EN,
                acpi_base + CS5536_PM_GPE0_EN);

        /* Clear pending events */
        outl(0xffffffff, acpi_base + CS5536_PM_GPE0_STS);
        process_sci_queue(false);

        /* Initial sync */
        send_ebook_state();
        detect_lid_state();
        send_lid_state();

        r = setup_sci_interrupt(pdev);
        if (r)
                goto err_sci;

        /* Enable all EC events */
        olpc_ec_mask_write(EC_SCI_SRC_ALL);

        return r;

err_sci:
        free_ec_sci();
err_ecsci:
        free_lid_events();
err_lidevt:
        free_lid_switch();
err_lid:
        free_ebook_switch();
err_ebook:
        free_power_button();
        return r;
}

static int xo1_sci_remove(struct platform_device *pdev)
{
        mfd_cell_disable(pdev);
        free_irq(sci_irq, pdev);
        cancel_work_sync(&sci_work);
        free_ec_sci();
        free_lid_events();
        free_lid_switch();
        free_ebook_switch();
        free_power_button();
        acpi_base = 0;
        return 0;
}

static struct platform_driver xo1_sci_driver = {
        .driver = {
                .name = "olpc-xo1-sci-acpi",
        },
        .probe = xo1_sci_probe,
        .remove = xo1_sci_remove,
        .suspend = xo1_sci_suspend,
        .resume = xo1_sci_resume,
};

static int __init xo1_sci_init(void)
{
        return platform_driver_register(&xo1_sci_driver);
}
arch_initcall(xo1_sci_init);