olpc-xo15-sci.c

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/*
 * Support for OLPC XO-1.5 System Control Interrupts (SCI)
 *
 * Copyright (C) 2009-2010 One Laptop per Child
 *
 * 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/device.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
#include <linux/power_supply.h>
#include <linux/olpc-ec.h>

#include <acpi/acpi_bus.h>
#include <acpi/acpi_drivers.h>
#include <asm/olpc.h>

#define DRV_NAME            "olpc-xo15-sci"
#define PFX             DRV_NAME ": "
#define XO15_SCI_CLASS          DRV_NAME
#define XO15_SCI_DEVICE_NAME        "OLPC XO-1.5 SCI"

static unsigned long            xo15_sci_gpe;
static bool             lid_wake_on_close;

/*
 * The normal ACPI LID wakeup behavior is wake-on-open, but not
 * wake-on-close. This is implemented as standard by the XO-1.5 DSDT.
 *
 * We provide here a sysfs attribute that will additionally enable
 * wake-on-close behavior. This is useful (e.g.) when we oportunistically
 * suspend with the display running; if the lid is then closed, we want to
 * wake up to turn the display off.
 *
 * This is controlled through a custom method in the XO-1.5 DSDT.
 */
static int set_lid_wake_behavior(bool wake_on_close)
{
    struct acpi_object_list arg_list;
    union acpi_object arg;
    acpi_status status;

    arg_list.count      = 1;
    arg_list.pointer    = &arg;
    arg.type        = ACPI_TYPE_INTEGER;
    arg.integer.value   = wake_on_close;

    status = acpi_evaluate_object(NULL, "\\_SB.PCI0.LID.LIDW", &arg_list, NULL);
    if (ACPI_FAILURE(status)) {
        pr_warning(PFX "failed to set lid behavior\n");
        return 1;
    }

    lid_wake_on_close = wake_on_close;

    return 0;
}

static ssize_t
lid_wake_on_close_show(struct kobject *s, struct kobj_attribute *attr, char *buf)
{
    return sprintf(buf, "%u\n", lid_wake_on_close);
}

static ssize_t lid_wake_on_close_store(struct kobject *s,
                       struct kobj_attribute *attr,
                       const char *buf, size_t n)
{
    unsigned int val;

    if (sscanf(buf, "%u", &val) != 1)
        return -EINVAL;

    set_lid_wake_behavior(!!val);

    return n;
}

static struct kobj_attribute lid_wake_on_close_attr =
    __ATTR(lid_wake_on_close, 0644,
           lid_wake_on_close_show,
           lid_wake_on_close_store);

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);
    }
}

static void process_sci_queue(void)
{
    u16 data;
    int r;

    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;
        }
    } 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();
}

static DECLARE_WORK(sci_work, process_sci_queue_work);

static u32 xo15_sci_gpe_handler(acpi_handle gpe_device, u32 gpe, void *context)
{
    schedule_work(&sci_work);
    return ACPI_INTERRUPT_HANDLED | ACPI_REENABLE_GPE;
}

static int xo15_sci_add(struct acpi_device *device)
{
    unsigned long long tmp;
    acpi_status status;
    int r;

    if (!device)
        return -EINVAL;

    strcpy(acpi_device_name(device), XO15_SCI_DEVICE_NAME);
    strcpy(acpi_device_class(device), XO15_SCI_CLASS);

    /* Get GPE bit assignment (EC events). */
    status = acpi_evaluate_integer(device->handle, "_GPE", NULL, &tmp);
    if (ACPI_FAILURE(status))
        return -EINVAL;

    xo15_sci_gpe = tmp;
    status = acpi_install_gpe_handler(NULL, xo15_sci_gpe,
                      ACPI_GPE_EDGE_TRIGGERED,
                      xo15_sci_gpe_handler, device);
    if (ACPI_FAILURE(status))
        return -ENODEV;

    dev_info(&device->dev, "Initialized, GPE = 0x%lx\n", xo15_sci_gpe);

    r = sysfs_create_file(&device->dev.kobj, &lid_wake_on_close_attr.attr);
    if (r)
        goto err_sysfs;

    /* Flush queue, and enable all SCI events */
    process_sci_queue();
    olpc_ec_mask_write(EC_SCI_SRC_ALL);

    acpi_enable_gpe(NULL, xo15_sci_gpe);

    /* Enable wake-on-EC */
    if (device->wakeup.flags.valid)
        device_init_wakeup(&device->dev, true);

    return 0;

err_sysfs:
    acpi_remove_gpe_handler(NULL, xo15_sci_gpe, xo15_sci_gpe_handler);
    cancel_work_sync(&sci_work);
    return r;
}

static int xo15_sci_remove(struct acpi_device *device, int type)
{
    acpi_disable_gpe(NULL, xo15_sci_gpe);
    acpi_remove_gpe_handler(NULL, xo15_sci_gpe, xo15_sci_gpe_handler);
    cancel_work_sync(&sci_work);
    sysfs_remove_file(&device->dev.kobj, &lid_wake_on_close_attr.attr);
    return 0;
}

static int xo15_sci_resume(struct device *dev)
{
    /* Enable all EC events */
    olpc_ec_mask_write(EC_SCI_SRC_ALL);

    /* Power/battery status might have changed */
    battery_status_changed();
    ac_status_changed();

    return 0;
}

static SIMPLE_DEV_PM_OPS(xo15_sci_pm, NULL, xo15_sci_resume);

static const struct acpi_device_id xo15_sci_device_ids[] = {
    {"XO15EC", 0},
    {"", 0},
};

static struct acpi_driver xo15_sci_drv = {
    .name = DRV_NAME,
    .class = XO15_SCI_CLASS,
    .ids = xo15_sci_device_ids,
    .ops = {
        .add = xo15_sci_add,
        .remove = xo15_sci_remove,
    },
    .drv.pm = &xo15_sci_pm,
};

static int __init xo15_sci_init(void)
{
    return acpi_bus_register_driver(&xo15_sci_drv);
}
device_initcall(xo15_sci_init);