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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, 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 | */ | |
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 | ||
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 | ||
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 | ||
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 | ||
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 | ||
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 | ||
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"); |