C180_oyster_driver/sysfs_power.c

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/kobject.h>
#include <linux/sysfs.h>
#include <linux/acpi.h>
#include <linux/io.h>
#include <linux/delay.h>
#include "gpioregs.h"

extern struct kobject *hwmon_kobj;

static int wait_ibf(void)
{
    int i = 0;
    while (inb(EC_CMD_PORT) & EC_IBF)
    {
        if (++i > TIMEOUT_LOOPS)
        {
            return -1;
        }
        udelay(1);
    }
    return 0;
}

static int wait_obf(void)
{
    int i = 0;
    while (!(inb(EC_CMD_PORT) & EC_OBF))
    {
        if (++i > TIMEOUT_LOOPS)
        {
            return -1;
        }
        udelay(1);
    }
    return 0;
}

static int oem_ec_read_ram(uint8_t page, uint8_t offset, uint8_t *data)
{
    unsigned char WEC, REC;
    switch (page)
    {
    case 0:
    {
        WEC = 0x96;
        REC = 0x95;
        break;
    }

    case 1:
    {
        WEC = 0x98;
        REC = 0x97;
        break;
    }

    default:
    {
        WEC = 0x81;
        REC = 0x80;
        break;
    }
    }
    if (wait_ibf() < 0)
        return -1;
    outb(REC, EC_CMD_PORT);

    if (wait_ibf() < 0)
        return -1;
    outb(offset, EC_DATA_PORT);

    if (wait_obf() < 0)
        return -1;
    *data = inb(EC_DATA_PORT);

    return 0;
}

static ssize_t ac_power_show(struct kobject *kobj, struct kobj_attribute *attr,
                             char *buf)
{
    int ac_power_flag = 0;
    uint8_t val = 0x00;
    if (oem_ec_read_ram(2, 0x36, &val) < 0)
        return -1;
    ac_power_flag = (val & 0x03) ? 1 : 0;

    return sprintf(buf, "%d\n", ac_power_flag);
}

static ssize_t ac_power_store(struct kobject *kobj, struct kobj_attribute *attr,
                              const char *buf, size_t count)
{
    return -EINVAL;
}

static struct kobj_attribute ac_power =
    __ATTR(ac_power, 0644, ac_power_show, ac_power_store);

static struct attribute *sysfs_power_attrs[] = {
    &ac_power.attr,
    NULL,
};

static struct attribute_group sysfs_power_attr_group = {
    .attrs = sysfs_power_attrs,
};

int sysfs_power_init(void)
{
    int ret = 0;

    ret = sysfs_create_group(hwmon_kobj, &sysfs_power_attr_group);

    return ret;
}

void sysfs_power_exit(void)
{
    sysfs_remove_group(hwmon_kobj, &sysfs_power_attr_group);
}