linux-imx

/*

 * Copyright (C) ST-Ericsson 2010 - 2013

 * Author: Martin Persson <martin.persson@stericsson.com>

 *         Hongbo Zhang <hongbo.zhang@linaro.org>

 * License Terms: GNU General Public License v2

 *

 * When the AB8500 thermal warning temperature is reached (threshold cannot

 * be changed by SW), an interrupt is set, and if no further action is taken

 * within a certain time frame, kernel_power_off will be called.

 *

 * When AB8500 thermal shutdown temperature is reached a hardware shutdown of

 * the AB8500 will occur.

 */

​

#include <linux/err.h>

#include <linux/hwmon.h>

#include <linux/hwmon-sysfs.h>

#include <linux/mfd/abx500.h>

#include <linux/mfd/abx500/ab8500-bm.h>

#include <linux/mfd/abx500/ab8500-gpadc.h>

#include <linux/module.h>

#include <linux/platform_device.h>

#include <linux/power/ab8500.h>

#include <linux/reboot.h>

#include <linux/slab.h>

#include <linux/sysfs.h>

#include "abx500.h"

​

#define DEFAULT_POWER_OFF_DELAY (HZ * 10)

#define THERMAL_VCC     1800

#define PULL_UP_RESISTOR    47000

/* Number of monitored sensors should not greater than NUM_SENSORS */

#define NUM_MONITORED_SENSORS   4

​

struct ab8500_gpadc_cfg {

    const struct abx500_res_to_temp *temp_tbl;

    int tbl_sz;

    int vcc;

    int r_up;

};

​

struct ab8500_temp {

    struct ab8500_gpadc *gpadc;

    struct ab8500_btemp *btemp;

    struct delayed_work power_off_work;

    struct ab8500_gpadc_cfg cfg;

    struct abx500_temp *abx500_data;

};

​

/*

 * The hardware connection is like this:

 * VCC----[ R_up ]-----[ NTC ]----GND

 * where R_up is pull-up resistance, and GPADC measures voltage on NTC.

 * and res_to_temp table is strictly sorted by falling resistance values.

 */

static int ab8500_voltage_to_temp(struct ab8500_gpadc_cfg *cfg,

        int v_ntc, int *temp)

{

    int r_ntc, i = 0, tbl_sz = cfg->tbl_sz;

    const struct abx500_res_to_temp *tbl = cfg->temp_tbl;

​

    if (cfg->vcc < 0 || v_ntc >= cfg->vcc)

        return -EINVAL;

​

    r_ntc = v_ntc * cfg->r_up / (cfg->vcc - v_ntc);

    if (r_ntc > tbl[0].resist || r_ntc < tbl[tbl_sz - 1].resist)

        return -EINVAL;

​

    while (!(r_ntc <= tbl[i].resist && r_ntc > tbl[i + 1].resist) &&

            i < tbl_sz - 2)

        i++;

​

    /* return milli-Celsius */

    *temp = tbl[i].temp * 1000 + ((tbl[i + 1].temp - tbl[i].temp) * 1000 *

        (r_ntc - tbl[i].resist)) / (tbl[i + 1].resist - tbl[i].resist);

​

    return 0;

}

​

static int ab8500_read_sensor(struct abx500_temp *data, u8 sensor, int *temp)

{

    int voltage, ret;

    struct ab8500_temp *ab8500_data = data->plat_data;

​

    if (sensor == BAT_CTRL) {

        *temp = ab8500_btemp_get_batctrl_temp(ab8500_data->btemp);

    } else if (sensor == BTEMP_BALL) {

        *temp = ab8500_btemp_get_temp(ab8500_data->btemp);

    } else {

        voltage = ab8500_gpadc_convert(ab8500_data->gpadc, sensor);

        if (voltage < 0)

            return voltage;