/* * 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, pm_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/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"); pm_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");