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1/*
2 * Copyright (C) ST-Ericsson 2010 - 2013
3 * Author: Martin Persson <martin.persson@stericsson.com>
4 * Hongbo Zhang <hongbo.zhang@linaro.org>
5 * License Terms: GNU General Public License v2
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/mfd/abx500/ab8500-gpadc.h>
21#include <linux/module.h>
22#include <linux/platform_device.h>
23#include <linux/power/ab8500.h>
24#include <linux/reboot.h>
25#include <linux/slab.h>
26#include <linux/sysfs.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/* Number of monitored sensors should not greater than NUM_SENSORS */
33#define NUM_MONITORED_SENSORS 4
34
35struct ab8500_gpadc_cfg {
36 const struct abx500_res_to_temp *temp_tbl;
37 int tbl_sz;
38 int vcc;
39 int r_up;
40};
41
42struct ab8500_temp {
43 struct ab8500_gpadc *gpadc;
44 struct ab8500_btemp *btemp;
45 struct delayed_work power_off_work;
46 struct ab8500_gpadc_cfg cfg;
47 struct abx500_temp *abx500_data;
48};
49
50/*
51 * The hardware connection is like this:
52 * VCC----[ R_up ]-----[ NTC ]----GND
53 * where R_up is pull-up resistance, and GPADC measures voltage on NTC.
54 * and res_to_temp table is strictly sorted by falling resistance values.
55 */
56static int ab8500_voltage_to_temp(struct ab8500_gpadc_cfg *cfg,
57 int v_ntc, int *temp)
58{
59 int r_ntc, i = 0, tbl_sz = cfg->tbl_sz;
60 const struct abx500_res_to_temp *tbl = cfg->temp_tbl;
61
62 if (cfg->vcc < 0 || v_ntc >= cfg->vcc)
63 return -EINVAL;
64
65 r_ntc = v_ntc * cfg->r_up / (cfg->vcc - v_ntc);
66 if (r_ntc > tbl[0].resist || r_ntc < tbl[tbl_sz - 1].resist)
67 return -EINVAL;
68
69 while (!(r_ntc <= tbl[i].resist && r_ntc > tbl[i + 1].resist) &&
70 i < tbl_sz - 2)
71 i++;
72
73 /* return milli-Celsius */
74 *temp = tbl[i].temp * 1000 + ((tbl[i + 1].temp - tbl[i].temp) * 1000 *
75 (r_ntc - tbl[i].resist)) / (tbl[i + 1].resist - tbl[i].resist);
76
77 return 0;
78}
79
80static int ab8500_read_sensor(struct abx500_temp *data, u8 sensor, int *temp)
81{
82 int voltage, ret;
83 struct ab8500_temp *ab8500_data = data->plat_data;
84
85 if (sensor == BAT_CTRL) {
86 *temp = ab8500_btemp_get_batctrl_temp(ab8500_data->btemp);
87 } else if (sensor == BTEMP_BALL) {
88 *temp = ab8500_btemp_get_temp(ab8500_data->btemp);
89 } else {
90 voltage = ab8500_gpadc_convert(ab8500_data->gpadc, sensor);
91 if (voltage < 0)
92 return voltage;
93
94 ret = ab8500_voltage_to_temp(&ab8500_data->cfg, voltage, temp);
95 if (ret < 0)
96 return ret;
97 }
98
99 return 0;
100}
101
102static void ab8500_thermal_power_off(struct work_struct *work)
103{
104 struct ab8500_temp *ab8500_data = container_of(work,
105 struct ab8500_temp, power_off_work.work);
106 struct abx500_temp *abx500_data = ab8500_data->abx500_data;
107
108 dev_warn(&abx500_data->pdev->dev, "Power off due to critical temp\n");
109
110 kernel_power_off();
111}
112
113static ssize_t ab8500_show_name(struct device *dev,
114 struct device_attribute *devattr, char *buf)
115{
116 return sprintf(buf, "ab8500\n");
117}
118
119static ssize_t ab8500_show_label(struct device *dev,
120 struct device_attribute *devattr, char *buf)
121{
122 char *label;
123 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
124 int index = attr->index;
125
126 switch (index) {
127 case 1:
128 label = "ext_adc1";
129 break;
130 case 2:
131 label = "ext_adc2";
132 break;
133 case 3:
134 label = "bat_temp";
135 break;
136 case 4:
137 label = "bat_ctrl";
138 break;
139 default:
140 return -EINVAL;
141 }
142
143 return sprintf(buf, "%s\n", label);
144}
145
146static int ab8500_temp_irq_handler(int irq, struct abx500_temp *data)
147{
148 struct ab8500_temp *ab8500_data = data->plat_data;
149
150 dev_warn(&data->pdev->dev, "Power off in %d s\n",
151 DEFAULT_POWER_OFF_DELAY / HZ);
152
153 schedule_delayed_work(&ab8500_data->power_off_work,
154 DEFAULT_POWER_OFF_DELAY);
155 return 0;
156}
157
158int abx500_hwmon_init(struct abx500_temp *data)
159{
160 struct ab8500_temp *ab8500_data;
161
162 ab8500_data = devm_kzalloc(&data->pdev->dev, sizeof(*ab8500_data),
163 GFP_KERNEL);
164 if (!ab8500_data)
165 return -ENOMEM;
166
167 ab8500_data->gpadc = ab8500_gpadc_get("ab8500-gpadc.0");
168 if (IS_ERR(ab8500_data->gpadc))
169 return PTR_ERR(ab8500_data->gpadc);
170
171 ab8500_data->btemp = ab8500_btemp_get();
172 if (IS_ERR(ab8500_data->btemp))
173 return PTR_ERR(ab8500_data->btemp);
174
175 INIT_DELAYED_WORK(&ab8500_data->power_off_work,
176 ab8500_thermal_power_off);
177
178 ab8500_data->cfg.vcc = THERMAL_VCC;
179 ab8500_data->cfg.r_up = PULL_UP_RESISTOR;
180 ab8500_data->cfg.temp_tbl = ab8500_temp_tbl_a_thermistor;
181 ab8500_data->cfg.tbl_sz = ab8500_temp_tbl_a_size;
182
183 data->plat_data = ab8500_data;
184
185 /*
186 * ADC_AUX1 and ADC_AUX2, connected to external NTC
187 * BTEMP_BALL and BAT_CTRL, fixed usage
188 */
189 data->gpadc_addr[0] = ADC_AUX1;
190 data->gpadc_addr[1] = ADC_AUX2;
191 data->gpadc_addr[2] = BTEMP_BALL;
192 data->gpadc_addr[3] = BAT_CTRL;
193 data->monitored_sensors = NUM_MONITORED_SENSORS;
194
195 data->ops.read_sensor = ab8500_read_sensor;
196 data->ops.irq_handler = ab8500_temp_irq_handler;
197 data->ops.show_name = ab8500_show_name;
198 data->ops.show_label = ab8500_show_label;
199 data->ops.is_visible = NULL;
200
201 return 0;
202}
203EXPORT_SYMBOL(abx500_hwmon_init);
204
205MODULE_AUTHOR("Hongbo Zhang <hongbo.zhang@linaro.org>");
206MODULE_DESCRIPTION("AB8500 temperature driver");
207MODULE_LICENSE("GPL");
208

Warning: That file was not part of the compilation database. It may have many parsing errors.