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04930baf PR |
1 | /* |
2 | * Nokia RX-51 battery driver | |
3 | * | |
4 | * Copyright (C) 2012 Pali Rohár <pali.rohar@gmail.com> | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; either version 2 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License along | |
17 | * with this program; if not, write to the Free Software Foundation, Inc., | |
18 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. | |
19 | */ | |
20 | ||
21 | #include <linux/module.h> | |
22 | #include <linux/param.h> | |
23 | #include <linux/platform_device.h> | |
24 | #include <linux/power_supply.h> | |
25 | #include <linux/slab.h> | |
26 | #include <linux/i2c/twl4030-madc.h> | |
27 | ||
28 | struct rx51_device_info { | |
29 | struct device *dev; | |
30 | struct power_supply bat; | |
31 | }; | |
32 | ||
33 | /* | |
34 | * Read ADCIN channel value, code copied from maemo kernel | |
35 | */ | |
36 | static int rx51_battery_read_adc(int channel) | |
37 | { | |
38 | struct twl4030_madc_request req; | |
39 | ||
40 | req.channels = 1 << channel; | |
41 | req.do_avg = 1; | |
42 | req.method = TWL4030_MADC_SW1; | |
43 | req.func_cb = NULL; | |
44 | req.type = TWL4030_MADC_WAIT; | |
45 | ||
46 | if (twl4030_madc_conversion(&req) <= 0) | |
47 | return -ENODATA; | |
48 | ||
49 | return req.rbuf[channel]; | |
50 | } | |
51 | ||
52 | /* | |
53 | * Read ADCIN channel 12 (voltage) and convert RAW value to micro voltage | |
54 | * This conversion formula was extracted from maemo program bsi-read | |
55 | */ | |
56 | static int rx51_battery_read_voltage(struct rx51_device_info *di) | |
57 | { | |
58 | int voltage = rx51_battery_read_adc(12); | |
59 | ||
60 | if (voltage < 0) | |
61 | return voltage; | |
62 | ||
63 | return 1000 * (10000 * voltage / 1705); | |
64 | } | |
65 | ||
66 | /* | |
67 | * Temperature look-up tables | |
68 | * TEMP = (1/(t1 + 1/298) - 273.15) | |
69 | * Where t1 = (1/B) * ln((RAW_ADC_U * 2.5)/(R * I * 255)) | |
70 | * Formula is based on experimental data, RX-51 CAL data, maemo program bme | |
71 | * and formula from da9052 driver with values R = 100, B = 3380, I = 0.00671 | |
72 | */ | |
73 | ||
74 | /* | |
75 | * Table1 (temperature for first 25 RAW values) | |
76 | * Usage: TEMP = rx51_temp_table1[RAW] | |
77 | * RAW is between 1 and 24 | |
78 | * TEMP is between 201 C and 55 C | |
79 | */ | |
80 | static u8 rx51_temp_table1[] = { | |
81 | 255, 201, 159, 138, 124, 114, 106, 99, 94, 89, 85, 82, 78, 75, | |
82 | 73, 70, 68, 66, 64, 62, 61, 59, 57, 56, 55 | |
83 | }; | |
84 | ||
85 | /* | |
86 | * Table2 (lowest RAW value for temperature) | |
87 | * Usage: RAW = rx51_temp_table2[TEMP-rx51_temp_table2_first] | |
88 | * TEMP is between 53 C and -32 C | |
89 | * RAW is between 25 and 993 | |
90 | */ | |
91 | #define rx51_temp_table2_first 53 | |
92 | static u16 rx51_temp_table2[] = { | |
93 | 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 39, | |
94 | 40, 41, 43, 44, 46, 48, 49, 51, 53, 55, 57, 59, 61, 64, | |
95 | 66, 69, 71, 74, 77, 80, 83, 86, 90, 94, 97, 101, 106, 110, | |
96 | 115, 119, 125, 130, 136, 141, 148, 154, 161, 168, 176, 184, 202, 211, | |
97 | 221, 231, 242, 254, 266, 279, 293, 308, 323, 340, 357, 375, 395, 415, | |
98 | 437, 460, 485, 511, 539, 568, 600, 633, 669, 706, 747, 790, 836, 885, | |
99 | 937, 993, 1024 | |
100 | }; | |
101 | ||
102 | /* | |
103 | * Read ADCIN channel 0 (battery temp) and convert value to tenths of Celsius | |
104 | * Use Temperature look-up tables for conversation | |
105 | */ | |
106 | static int rx51_battery_read_temperature(struct rx51_device_info *di) | |
107 | { | |
108 | int min = 0; | |
109 | int max = ARRAY_SIZE(rx51_temp_table2) - 1; | |
110 | int raw = rx51_battery_read_adc(0); | |
111 | ||
112 | /* Zero and negative values are undefined */ | |
113 | if (raw <= 0) | |
114 | return INT_MAX; | |
115 | ||
116 | /* ADC channels are 10 bit, higher value are undefined */ | |
117 | if (raw >= (1 << 10)) | |
118 | return INT_MIN; | |
119 | ||
120 | /* First check for temperature in first direct table */ | |
121 | if (raw < ARRAY_SIZE(rx51_temp_table1)) | |
122 | return rx51_temp_table1[raw] * 100; | |
123 | ||
124 | /* Binary search RAW value in second inverse table */ | |
125 | while (max - min > 1) { | |
126 | int mid = (max + min) / 2; | |
127 | if (rx51_temp_table2[mid] <= raw) | |
128 | min = mid; | |
129 | else if (rx51_temp_table2[mid] > raw) | |
130 | max = mid; | |
131 | if (rx51_temp_table2[mid] == raw) | |
132 | break; | |
133 | } | |
134 | ||
135 | return (rx51_temp_table2_first - min) * 100; | |
136 | } | |
137 | ||
138 | /* | |
139 | * Read ADCIN channel 4 (BSI) and convert RAW value to micro Ah | |
140 | * This conversion formula was extracted from maemo program bsi-read | |
141 | */ | |
142 | static int rx51_battery_read_capacity(struct rx51_device_info *di) | |
143 | { | |
144 | int capacity = rx51_battery_read_adc(4); | |
145 | ||
146 | if (capacity < 0) | |
147 | return capacity; | |
148 | ||
149 | return 1280 * (1200 * capacity)/(1024 - capacity); | |
150 | } | |
151 | ||
152 | /* | |
153 | * Return power_supply property | |
154 | */ | |
155 | static int rx51_battery_get_property(struct power_supply *psy, | |
156 | enum power_supply_property psp, | |
157 | union power_supply_propval *val) | |
158 | { | |
159 | struct rx51_device_info *di = container_of((psy), | |
160 | struct rx51_device_info, bat); | |
161 | ||
162 | switch (psp) { | |
163 | case POWER_SUPPLY_PROP_TECHNOLOGY: | |
164 | val->intval = POWER_SUPPLY_TECHNOLOGY_LION; | |
165 | break; | |
166 | case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN: | |
167 | val->intval = 4200000; | |
168 | break; | |
169 | case POWER_SUPPLY_PROP_PRESENT: | |
170 | val->intval = rx51_battery_read_voltage(di) ? 1 : 0; | |
171 | break; | |
172 | case POWER_SUPPLY_PROP_VOLTAGE_NOW: | |
173 | val->intval = rx51_battery_read_voltage(di); | |
174 | break; | |
175 | case POWER_SUPPLY_PROP_TEMP: | |
176 | val->intval = rx51_battery_read_temperature(di); | |
177 | break; | |
178 | case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN: | |
179 | val->intval = rx51_battery_read_capacity(di); | |
180 | break; | |
181 | default: | |
182 | return -EINVAL; | |
183 | } | |
184 | ||
185 | if (val->intval == INT_MAX || val->intval == INT_MIN) | |
186 | return -EINVAL; | |
187 | ||
188 | return 0; | |
189 | } | |
190 | ||
191 | static enum power_supply_property rx51_battery_props[] = { | |
192 | POWER_SUPPLY_PROP_TECHNOLOGY, | |
193 | POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN, | |
194 | POWER_SUPPLY_PROP_PRESENT, | |
195 | POWER_SUPPLY_PROP_VOLTAGE_NOW, | |
196 | POWER_SUPPLY_PROP_TEMP, | |
197 | POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN, | |
198 | }; | |
199 | ||
200 | static int __devinit rx51_battery_probe(struct platform_device *pdev) | |
201 | { | |
202 | struct rx51_device_info *di; | |
203 | int ret; | |
204 | ||
205 | di = kzalloc(sizeof(*di), GFP_KERNEL); | |
206 | if (!di) | |
207 | return -ENOMEM; | |
208 | ||
209 | platform_set_drvdata(pdev, di); | |
210 | ||
211 | di->bat.name = dev_name(&pdev->dev); | |
212 | di->bat.type = POWER_SUPPLY_TYPE_BATTERY; | |
213 | di->bat.properties = rx51_battery_props; | |
214 | di->bat.num_properties = ARRAY_SIZE(rx51_battery_props); | |
215 | di->bat.get_property = rx51_battery_get_property; | |
216 | ||
217 | ret = power_supply_register(di->dev, &di->bat); | |
218 | if (ret) { | |
219 | platform_set_drvdata(pdev, NULL); | |
220 | kfree(di); | |
221 | return ret; | |
222 | } | |
223 | ||
224 | return 0; | |
225 | } | |
226 | ||
227 | static int __devexit rx51_battery_remove(struct platform_device *pdev) | |
228 | { | |
229 | struct rx51_device_info *di = platform_get_drvdata(pdev); | |
230 | ||
231 | power_supply_unregister(&di->bat); | |
232 | platform_set_drvdata(pdev, NULL); | |
233 | kfree(di); | |
234 | ||
235 | return 0; | |
236 | } | |
237 | ||
238 | static struct platform_driver rx51_battery_driver = { | |
239 | .probe = rx51_battery_probe, | |
240 | .remove = __devexit_p(rx51_battery_remove), | |
241 | .driver = { | |
242 | .name = "rx51-battery", | |
243 | .owner = THIS_MODULE, | |
244 | }, | |
245 | }; | |
246 | module_platform_driver(rx51_battery_driver); | |
247 | ||
248 | MODULE_ALIAS("platform:rx51-battery"); | |
249 | MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>"); | |
250 | MODULE_DESCRIPTION("Nokia RX-51 battery driver"); | |
251 | MODULE_LICENSE("GPL"); |