diff options
Diffstat (limited to 'drivers/hwmon/ab8500.c')
| -rw-r--r-- | drivers/hwmon/ab8500.c | 207 |
1 files changed, 207 insertions, 0 deletions
diff --git a/drivers/hwmon/ab8500.c b/drivers/hwmon/ab8500.c new file mode 100644 index 000000000..8b6a4f4c8 --- /dev/null +++ b/drivers/hwmon/ab8500.c @@ -0,0 +1,207 @@ +/* + * 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"); |