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/*
* 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;
ret = ab8500_voltage_to_temp(&ab8500_data->cfg, voltage, temp);
if (ret < 0)
return ret;
}
return 0;
}
static void ab8500_thermal_power_off(struct work_struct *work)
{
struct ab8500_temp *ab8500_data = container_of(work,
struct ab8500_temp, power_off_work.work);
struct abx500_temp *abx500_data = ab8500_data->abx500_data;
dev_warn(&abx500_data->pdev->dev, "Power off due to critical temp\n");
kernel_power_off();
}
static ssize_t ab8500_show_name(struct device *dev,
struct device_attribute *devattr, char *buf)
{
return sprintf(buf, "ab8500\n");
}
static ssize_t ab8500_show_label(struct device *dev,
struct device_attribute *devattr, char *buf)
{
char *label;
struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
int index = attr->index;
switch (index) {
case 1:
label = "ext_adc1";
break;
case 2:
label = "ext_adc2";
break;
case 3:
label = "bat_temp";
break;
case 4:
label = "bat_ctrl";
break;
default:
return -EINVAL;
}
return sprintf(buf, "%s\n", label);
}
static int ab8500_temp_irq_handler(int irq, struct abx500_temp *data)
{
struct ab8500_temp *ab8500_data = data->plat_data;
dev_warn(&data->pdev->dev, "Power off in %d s\n",
DEFAULT_POWER_OFF_DELAY / HZ);
schedule_delayed_work(&ab8500_data->power_off_work,
DEFAULT_POWER_OFF_DELAY);
return 0;
}
int abx500_hwmon_init(struct abx500_temp *data)
{
struct ab8500_temp *ab8500_data;
ab8500_data = devm_kzalloc(&data->pdev->dev, sizeof(*ab8500_data),
GFP_KERNEL);
if (!ab8500_data)
return -ENOMEM;
ab8500_data->gpadc = ab8500_gpadc_get("ab8500-gpadc.0");
if (IS_ERR(ab8500_data->gpadc))
return PTR_ERR(ab8500_data->gpadc);
ab8500_data->btemp = ab8500_btemp_get();
if (IS_ERR(ab8500_data->btemp))
return PTR_ERR(ab8500_data->btemp);
INIT_DELAYED_WORK(&ab8500_data->power_off_work,
ab8500_thermal_power_off);
ab8500_data->cfg.vcc = THERMAL_VCC;
ab8500_data->cfg.r_up = PULL_UP_RESISTOR;
ab8500_data->cfg.temp_tbl = ab8500_temp_tbl_a_thermistor;
ab8500_data->cfg.tbl_sz = ab8500_temp_tbl_a_size;
data->plat_data = ab8500_data;
/*
* ADC_AUX1 and ADC_AUX2, connected to external NTC
* BTEMP_BALL and BAT_CTRL, fixed usage
*/
data->gpadc_addr[0] = ADC_AUX1;
data->gpadc_addr[1] = ADC_AUX2;
data->gpadc_addr[2] = BTEMP_BALL;
data->gpadc_addr[3] = BAT_CTRL;
data->monitored_sensors = NUM_MONITORED_SENSORS;
data->ops.read_sensor = ab8500_read_sensor;
data->ops.irq_handler = ab8500_temp_irq_handler;
data->ops.show_name = ab8500_show_name;
data->ops.show_label = ab8500_show_label;
data->ops.is_visible = NULL;
return 0;
}
EXPORT_SYMBOL(abx500_hwmon_init);
MODULE_AUTHOR("Hongbo Zhang <hongbo.zhang@linaro.org>");
MODULE_DESCRIPTION("AB8500 temperature driver");
MODULE_LICENSE("GPL");
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