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, pm_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/slab.h>
25 #include <linux/sysfs.h>
26 #include "abx500.h"
27
28 #define DEFAULT_POWER_OFF_DELAY (HZ * 10)
29 #define THERMAL_VCC 1800
30 #define PULL_UP_RESISTOR 47000
31 /* Number of monitored sensors should not greater than NUM_SENSORS */
32 #define NUM_MONITORED_SENSORS 4
33
34 struct ab8500_gpadc_cfg {
35 const struct abx500_res_to_temp *temp_tbl;
36 int tbl_sz;
37 int vcc;
38 int r_up;
39 };
40
41 struct ab8500_temp {
42 struct ab8500_gpadc *gpadc;
43 struct ab8500_btemp *btemp;
44 struct delayed_work power_off_work;
45 struct ab8500_gpadc_cfg cfg;
46 struct abx500_temp *abx500_data;
47 };
48
49 /*
50 * The hardware connection is like this:
51 * VCC----[ R_up ]-----[ NTC ]----GND
52 * where R_up is pull-up resistance, and GPADC measures voltage on NTC.
53 * and res_to_temp table is strictly sorted by falling resistance values.
54 */
ab8500_voltage_to_temp(struct ab8500_gpadc_cfg * cfg,int v_ntc,int * temp)55 static int ab8500_voltage_to_temp(struct ab8500_gpadc_cfg *cfg,
56 int v_ntc, int *temp)
57 {
58 int r_ntc, i = 0, tbl_sz = cfg->tbl_sz;
59 const struct abx500_res_to_temp *tbl = cfg->temp_tbl;
60
61 if (cfg->vcc < 0 || v_ntc >= cfg->vcc)
62 return -EINVAL;
63
64 r_ntc = v_ntc * cfg->r_up / (cfg->vcc - v_ntc);
65 if (r_ntc > tbl[0].resist || r_ntc < tbl[tbl_sz - 1].resist)
66 return -EINVAL;
67
68 while (!(r_ntc <= tbl[i].resist && r_ntc > tbl[i + 1].resist) &&
69 i < tbl_sz - 2)
70 i++;
71
72 /* return milli-Celsius */
73 *temp = tbl[i].temp * 1000 + ((tbl[i + 1].temp - tbl[i].temp) * 1000 *
74 (r_ntc - tbl[i].resist)) / (tbl[i + 1].resist - tbl[i].resist);
75
76 return 0;
77 }
78
ab8500_read_sensor(struct abx500_temp * data,u8 sensor,int * temp)79 static int ab8500_read_sensor(struct abx500_temp *data, u8 sensor, int *temp)
80 {
81 int voltage, ret;
82 struct ab8500_temp *ab8500_data = data->plat_data;
83
84 if (sensor == BAT_CTRL) {
85 *temp = ab8500_btemp_get_batctrl_temp(ab8500_data->btemp);
86 } else if (sensor == BTEMP_BALL) {
87 *temp = ab8500_btemp_get_temp(ab8500_data->btemp);
88 } else {
89 voltage = ab8500_gpadc_convert(ab8500_data->gpadc, sensor);
90 if (voltage < 0)
91 return voltage;
92
93 ret = ab8500_voltage_to_temp(&ab8500_data->cfg, voltage, temp);
94 if (ret < 0)
95 return ret;
96 }
97
98 return 0;
99 }
100
ab8500_thermal_power_off(struct work_struct * work)101 static void ab8500_thermal_power_off(struct work_struct *work)
102 {
103 struct ab8500_temp *ab8500_data = container_of(work,
104 struct ab8500_temp, power_off_work.work);
105 struct abx500_temp *abx500_data = ab8500_data->abx500_data;
106
107 dev_warn(&abx500_data->pdev->dev, "Power off due to critical temp\n");
108
109 pm_power_off();
110 }
111
ab8500_show_name(struct device * dev,struct device_attribute * devattr,char * buf)112 static ssize_t ab8500_show_name(struct device *dev,
113 struct device_attribute *devattr, char *buf)
114 {
115 return sprintf(buf, "ab8500\n");
116 }
117
ab8500_show_label(struct device * dev,struct device_attribute * devattr,char * buf)118 static ssize_t ab8500_show_label(struct device *dev,
119 struct device_attribute *devattr, char *buf)
120 {
121 char *label;
122 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
123 int index = attr->index;
124
125 switch (index) {
126 case 1:
127 label = "ext_adc1";
128 break;
129 case 2:
130 label = "ext_adc2";
131 break;
132 case 3:
133 label = "bat_temp";
134 break;
135 case 4:
136 label = "bat_ctrl";
137 break;
138 default:
139 return -EINVAL;
140 }
141
142 return sprintf(buf, "%s\n", label);
143 }
144
ab8500_temp_irq_handler(int irq,struct abx500_temp * data)145 static int ab8500_temp_irq_handler(int irq, struct abx500_temp *data)
146 {
147 struct ab8500_temp *ab8500_data = data->plat_data;
148
149 dev_warn(&data->pdev->dev, "Power off in %d s\n",
150 DEFAULT_POWER_OFF_DELAY / HZ);
151
152 schedule_delayed_work(&ab8500_data->power_off_work,
153 DEFAULT_POWER_OFF_DELAY);
154 return 0;
155 }
156
abx500_hwmon_init(struct abx500_temp * data)157 int abx500_hwmon_init(struct abx500_temp *data)
158 {
159 struct ab8500_temp *ab8500_data;
160
161 ab8500_data = devm_kzalloc(&data->pdev->dev, sizeof(*ab8500_data),
162 GFP_KERNEL);
163 if (!ab8500_data)
164 return -ENOMEM;
165
166 ab8500_data->gpadc = ab8500_gpadc_get("ab8500-gpadc.0");
167 if (IS_ERR(ab8500_data->gpadc))
168 return PTR_ERR(ab8500_data->gpadc);
169
170 ab8500_data->btemp = ab8500_btemp_get();
171 if (IS_ERR(ab8500_data->btemp))
172 return PTR_ERR(ab8500_data->btemp);
173
174 INIT_DELAYED_WORK(&ab8500_data->power_off_work,
175 ab8500_thermal_power_off);
176
177 ab8500_data->cfg.vcc = THERMAL_VCC;
178 ab8500_data->cfg.r_up = PULL_UP_RESISTOR;
179 ab8500_data->cfg.temp_tbl = ab8500_temp_tbl_a_thermistor;
180 ab8500_data->cfg.tbl_sz = ab8500_temp_tbl_a_size;
181
182 data->plat_data = ab8500_data;
183
184 /*
185 * ADC_AUX1 and ADC_AUX2, connected to external NTC
186 * BTEMP_BALL and BAT_CTRL, fixed usage
187 */
188 data->gpadc_addr[0] = ADC_AUX1;
189 data->gpadc_addr[1] = ADC_AUX2;
190 data->gpadc_addr[2] = BTEMP_BALL;
191 data->gpadc_addr[3] = BAT_CTRL;
192 data->monitored_sensors = NUM_MONITORED_SENSORS;
193
194 data->ops.read_sensor = ab8500_read_sensor;
195 data->ops.irq_handler = ab8500_temp_irq_handler;
196 data->ops.show_name = ab8500_show_name;
197 data->ops.show_label = ab8500_show_label;
198 data->ops.is_visible = NULL;
199
200 return 0;
201 }
202 EXPORT_SYMBOL(abx500_hwmon_init);
203
204 MODULE_AUTHOR("Hongbo Zhang <hongbo.zhang@linaro.org>");
205 MODULE_DESCRIPTION("AB8500 temperature driver");
206 MODULE_LICENSE("GPL");
207