olpc-xo1-sci.c

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/*
 * 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 __devinit 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 __devinit 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 __devinit 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 __devinit 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);
    input_free_device(power_button_idev);
}

static int __devinit 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);
    input_free_device(ebook_switch_idev);
}

static int __devinit 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);
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);
    input_free_device(lid_switch_idev);
}

static int __devinit 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 __devexit 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 = __devexit_p(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);