drivers/hwmon/ab8500.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) ST-Ericsson 2010 - 2013
   4  * Author: Martin Persson <martin.persson@stericsson.com>
   5  *         Hongbo Zhang <hongbo.zhang@linaro.org>
   6  *
   7  * When the AB8500 thermal warning temperature is reached (threshold cannot
   8  * be changed by SW), an interrupt is set, and if no further action is taken
   9  * within a certain time frame, kernel_power_off will be called.
  10  *
  11  * When AB8500 thermal shutdown temperature is reached a hardware shutdown of
  12  * the AB8500 will occur.
  13  */
  14
  15 #include <linux/err.h>
  16 #include <linux/hwmon.h>
  17 #include <linux/hwmon-sysfs.h>
  18 #include <linux/mfd/abx500.h>
  19 #include <linux/mfd/abx500/ab8500-bm.h>
  20 #include <linux/module.h>
  21 #include <linux/platform_device.h>
  22 #include <linux/power/ab8500.h>
  23 #include <linux/reboot.h>
  24 #include <linux/slab.h>
  25 #include <linux/sysfs.h>
  26 #include <linux/iio/consumer.h>
  27 #include "abx500.h"
  28
  29 #define DEFAULT_POWER_OFF_DELAY (HZ * 10)
  30 #define THERMAL_VCC             1800
  31 #define PULL_UP_RESISTOR        47000
  32
  33 #define AB8500_SENSOR_AUX1              0
  34 #define AB8500_SENSOR_AUX2              1
  35 #define AB8500_SENSOR_BTEMP_BALL        2
  36 #define AB8500_SENSOR_BAT_CTRL          3
  37 #define NUM_MONITORED_SENSORS           4
  38
  39 struct ab8500_gpadc_cfg {
  40         const struct abx500_res_to_temp *temp_tbl;
  41         int tbl_sz;
  42         int vcc;
  43         int r_up;
  44 };
  45
  46 struct ab8500_temp {
  47         struct iio_channel *aux1;
  48         struct iio_channel *aux2;
  49         struct ab8500_btemp *btemp;
  50         struct delayed_work power_off_work;
  51         struct ab8500_gpadc_cfg cfg;
  52         struct abx500_temp *abx500_data;
  53 };
  54
  55 /*
  56  * The hardware connection is like this:
  57  * VCC----[ R_up ]-----[ NTC ]----GND
  58  * where R_up is pull-up resistance, and GPADC measures voltage on NTC.
  59  * and res_to_temp table is strictly sorted by falling resistance values.
  60  */
  61 static int ab8500_voltage_to_temp(struct ab8500_gpadc_cfg *cfg,
  62                 int v_ntc, int *temp)
  63 {
  64         int r_ntc, i = 0, tbl_sz = cfg->tbl_sz;
  65         const struct abx500_res_to_temp *tbl = cfg->temp_tbl;
  66
  67         if (cfg->vcc < 0 || v_ntc >= cfg->vcc)
  68                 return -EINVAL;
  69
  70         r_ntc = v_ntc * cfg->r_up / (cfg->vcc - v_ntc);
  71         if (r_ntc > tbl[0].resist || r_ntc < tbl[tbl_sz - 1].resist)
  72                 return -EINVAL;
  73
  74         while (!(r_ntc <= tbl[i].resist && r_ntc > tbl[i + 1].resist) &&
  75                         i < tbl_sz - 2)
  76                 i++;
  77
  78         /* return milli-Celsius */
  79         *temp = tbl[i].temp * 1000 + ((tbl[i + 1].temp - tbl[i].temp) * 1000 *
  80                 (r_ntc - tbl[i].resist)) / (tbl[i + 1].resist - tbl[i].resist);
  81
  82         return 0;
  83 }
  84
  85 static int ab8500_read_sensor(struct abx500_temp *data, u8 sensor, int *temp)
  86 {
  87         int voltage, ret;
  88         struct ab8500_temp *ab8500_data = data->plat_data;
  89
  90         if (sensor == AB8500_SENSOR_BTEMP_BALL) {
  91                 *temp = ab8500_btemp_get_temp(ab8500_data->btemp);
  92         } else if (sensor == AB8500_SENSOR_BAT_CTRL) {
  93                 *temp = ab8500_btemp_get_batctrl_temp(ab8500_data->btemp);
  94         } else if (sensor == AB8500_SENSOR_AUX1) {
  95                 ret = iio_read_channel_processed(ab8500_data->aux1, &voltage);
  96                 if (ret < 0)
  97                         return ret;
  98                 ret = ab8500_voltage_to_temp(&ab8500_data->cfg, voltage, temp);
  99                 if (ret < 0)
 100                         return ret;
 101         } else if (sensor == AB8500_SENSOR_AUX2) {
 102                 ret = iio_read_channel_processed(ab8500_data->aux2, &voltage);
 103                 if (ret < 0)
 104                         return ret;
 105                 ret = ab8500_voltage_to_temp(&ab8500_data->cfg, voltage, temp);
 106                 if (ret < 0)
 107                         return ret;
 108         }
 109
 110         return 0;
 111 }
 112
 113 static void ab8500_thermal_power_off(struct work_struct *work)
 114 {
 115         struct ab8500_temp *ab8500_data = container_of(work,
 116                                 struct ab8500_temp, power_off_work.work);
 117         struct abx500_temp *abx500_data = ab8500_data->abx500_data;
 118
 119         dev_warn(&abx500_data->pdev->dev, "Power off due to critical temp\n");
 120
 121         kernel_power_off();
 122 }
 123
 124 static ssize_t ab8500_show_name(struct device *dev,
 125                 struct device_attribute *devattr, char *buf)
 126 {
 127         return sprintf(buf, "ab8500\n");
 128 }
 129
 130 static ssize_t ab8500_show_label(struct device *dev,
 131                 struct device_attribute *devattr, char *buf)
 132 {
 133         char *label;
 134         struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
 135         int index = attr->index;
 136
 137         switch (index) {
 138         case 1:
 139                 label = "ext_adc1";
 140                 break;
 141         case 2:
 142                 label = "ext_adc2";
 143                 break;
 144         case 3:
 145                 label = "bat_temp";
 146                 break;
 147         case 4:
 148                 label = "bat_ctrl";
 149                 break;
 150         default:
 151                 return -EINVAL;
 152         }
 153
 154         return sprintf(buf, "%s\n", label);
 155 }
 156
 157 static int ab8500_temp_irq_handler(int irq, struct abx500_temp *data)
 158 {
 159         struct ab8500_temp *ab8500_data = data->plat_data;
 160
 161         dev_warn(&data->pdev->dev, "Power off in %d s\n",
 162                  DEFAULT_POWER_OFF_DELAY / HZ);
 163
 164         schedule_delayed_work(&ab8500_data->power_off_work,
 165                 DEFAULT_POWER_OFF_DELAY);
 166         return 0;
 167 }
 168
 169 int abx500_hwmon_init(struct abx500_temp *data)
 170 {
 171         struct ab8500_temp *ab8500_data;
 172
 173         ab8500_data = devm_kzalloc(&data->pdev->dev, sizeof(*ab8500_data),
 174                 GFP_KERNEL);
 175         if (!ab8500_data)
 176                 return -ENOMEM;
 177
 178         ab8500_data->btemp = ab8500_btemp_get();
 179         if (IS_ERR(ab8500_data->btemp))
 180                 return PTR_ERR(ab8500_data->btemp);
 181
 182         INIT_DELAYED_WORK(&ab8500_data->power_off_work,
 183                           ab8500_thermal_power_off);
 184
 185         ab8500_data->cfg.vcc = THERMAL_VCC;
 186         ab8500_data->cfg.r_up = PULL_UP_RESISTOR;
 187         ab8500_data->cfg.temp_tbl = ab8500_temp_tbl_a_thermistor;
 188         ab8500_data->cfg.tbl_sz = ab8500_temp_tbl_a_size;
 189
 190         data->plat_data = ab8500_data;
 191         ab8500_data->aux1 = devm_iio_channel_get(&data->pdev->dev, "aux1");
 192         if (IS_ERR(ab8500_data->aux1)) {
 193                 if (PTR_ERR(ab8500_data->aux1) == -ENODEV)
 194                         return -EPROBE_DEFER;
 195                 dev_err(&data->pdev->dev, "failed to get AUX1 ADC channel\n");
 196                 return PTR_ERR(ab8500_data->aux1);
 197         }
 198         ab8500_data->aux2 = devm_iio_channel_get(&data->pdev->dev, "aux2");
 199         if (IS_ERR(ab8500_data->aux2)) {
 200                 if (PTR_ERR(ab8500_data->aux2) == -ENODEV)
 201                         return -EPROBE_DEFER;
 202                 dev_err(&data->pdev->dev, "failed to get AUX2 ADC channel\n");
 203                 return PTR_ERR(ab8500_data->aux2);
 204         }
 205
 206         data->gpadc_addr[0] = AB8500_SENSOR_AUX1;
 207         data->gpadc_addr[1] = AB8500_SENSOR_AUX2;
 208         data->gpadc_addr[2] = AB8500_SENSOR_BTEMP_BALL;
 209         data->gpadc_addr[3] = AB8500_SENSOR_BAT_CTRL;
 210         data->monitored_sensors = NUM_MONITORED_SENSORS;
 211
 212         data->ops.read_sensor = ab8500_read_sensor;
 213         data->ops.irq_handler = ab8500_temp_irq_handler;
 214         data->ops.show_name = ab8500_show_name;
 215         data->ops.show_label = ab8500_show_label;
 216         data->ops.is_visible = NULL;
 217
 218         return 0;
 219 }
 220 EXPORT_SYMBOL(abx500_hwmon_init);
 221
 222 MODULE_AUTHOR("Hongbo Zhang <hongbo.zhang@linaro.org>");
 223 MODULE_DESCRIPTION("AB8500 temperature driver");
 224 MODULE_LICENSE("GPL");