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c3ff9a67 GR |
1 | /* |
2 | * Hardware monitoring driver for LTC2978 | |
3 | * | |
4 | * Copyright (c) 2011 Ericsson AB. | |
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 | |
17 | * along with this program; if not, write to the Free Software | |
18 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
19 | */ | |
20 | ||
21 | #include <linux/kernel.h> | |
22 | #include <linux/module.h> | |
23 | #include <linux/init.h> | |
24 | #include <linux/err.h> | |
25 | #include <linux/slab.h> | |
26 | #include <linux/i2c.h> | |
27 | #include "pmbus.h" | |
28 | ||
29 | enum chips { ltc2978 }; | |
30 | ||
31 | #define LTC2978_MFR_VOUT_PEAK 0xdd | |
32 | #define LTC2978_MFR_VIN_PEAK 0xde | |
33 | #define LTC2978_MFR_TEMPERATURE_PEAK 0xdf | |
34 | #define LTC2978_MFR_SPECIAL_ID 0xe7 | |
35 | ||
36 | #define LTC2978_MFR_VOUT_MIN 0xfb | |
37 | #define LTC2978_MFR_VIN_MIN 0xfc | |
38 | #define LTC2978_MFR_TEMPERATURE_MIN 0xfd | |
39 | ||
40 | #define LTC2978_ID_REV1 0x0121 | |
41 | #define LTC2978_ID_REV2 0x0122 | |
42 | ||
43 | /* | |
44 | * LTC2978 clears peak data whenever the CLEAR_FAULTS command is executed, which | |
45 | * happens pretty much each time chip data is updated. Raw peak data therefore | |
46 | * does not provide much value. To be able to provide useful peak data, keep an | |
47 | * internal cache of measured peak data, which is only cleared if an explicit | |
48 | * "clear peak" command is executed for the sensor in question. | |
49 | */ | |
50 | struct ltc2978_data { | |
51 | enum chips id; | |
52 | int vin_min, vin_max; | |
53 | int temp_min, temp_max; | |
54 | int vout_min[8], vout_max[8]; | |
55 | struct pmbus_driver_info info; | |
56 | }; | |
57 | ||
58 | #define to_ltc2978_data(x) container_of(x, struct ltc2978_data, info) | |
59 | ||
60 | static inline int lin11_to_val(int data) | |
61 | { | |
62 | s16 e = ((s16)data) >> 11; | |
63 | s32 m = (((s16)(data << 5)) >> 5); | |
64 | ||
65 | /* | |
66 | * mantissa is 10 bit + sign, exponent adds up to 15 bit. | |
67 | * Add 6 bit to exponent for maximum accuracy (10 + 15 + 6 = 31). | |
68 | */ | |
69 | e += 6; | |
70 | return (e < 0 ? m >> -e : m << e); | |
71 | } | |
72 | ||
73 | static int ltc2978_read_word_data(struct i2c_client *client, int page, int reg) | |
74 | { | |
75 | const struct pmbus_driver_info *info = pmbus_get_driver_info(client); | |
76 | struct ltc2978_data *data = to_ltc2978_data(info); | |
77 | int ret; | |
78 | ||
79 | switch (reg) { | |
80 | case PMBUS_VIRT_READ_VIN_MAX: | |
81 | ret = pmbus_read_word_data(client, page, LTC2978_MFR_VIN_PEAK); | |
82 | if (ret >= 0) { | |
83 | if (lin11_to_val(ret) > lin11_to_val(data->vin_max)) | |
84 | data->vin_max = ret; | |
85 | ret = data->vin_max; | |
86 | } | |
87 | break; | |
88 | case PMBUS_VIRT_READ_VOUT_MAX: | |
89 | ret = pmbus_read_word_data(client, page, LTC2978_MFR_VOUT_PEAK); | |
90 | if (ret >= 0) { | |
91 | /* | |
92 | * VOUT is 16 bit unsigned with fixed exponent, | |
93 | * so we can compare it directly | |
94 | */ | |
95 | if (ret > data->vout_max[page]) | |
96 | data->vout_max[page] = ret; | |
97 | ret = data->vout_max[page]; | |
98 | } | |
99 | break; | |
100 | case PMBUS_VIRT_READ_TEMP_MAX: | |
101 | ret = pmbus_read_word_data(client, page, | |
102 | LTC2978_MFR_TEMPERATURE_PEAK); | |
103 | if (ret >= 0) { | |
104 | if (lin11_to_val(ret) > lin11_to_val(data->temp_max)) | |
105 | data->temp_max = ret; | |
106 | ret = data->temp_max; | |
107 | } | |
108 | break; | |
109 | case PMBUS_VIRT_READ_VIN_MIN: | |
110 | ret = pmbus_read_word_data(client, page, LTC2978_MFR_VIN_MIN); | |
111 | if (ret >= 0) { | |
112 | if (lin11_to_val(ret) < lin11_to_val(data->vin_min)) | |
113 | data->vin_min = ret; | |
114 | ret = data->vin_min; | |
115 | } | |
116 | break; | |
117 | case PMBUS_VIRT_READ_VOUT_MIN: | |
118 | ret = pmbus_read_word_data(client, page, LTC2978_MFR_VOUT_MIN); | |
119 | if (ret >= 0) { | |
120 | /* | |
121 | * VOUT_MIN is known to not be supported on some lots | |
122 | * of LTC2978 revision 1, and will return the maximum | |
123 | * possible voltage if read. If VOUT_MAX is valid and | |
124 | * lower than the reading of VOUT_MIN, use it instead. | |
125 | */ | |
126 | if (data->vout_max[page] && ret > data->vout_max[page]) | |
127 | ret = data->vout_max[page]; | |
128 | if (ret < data->vout_min[page]) | |
129 | data->vout_min[page] = ret; | |
130 | ret = data->vout_min[page]; | |
131 | } | |
132 | break; | |
133 | case PMBUS_VIRT_READ_TEMP_MIN: | |
134 | ret = pmbus_read_word_data(client, page, | |
135 | LTC2978_MFR_TEMPERATURE_MIN); | |
136 | if (ret >= 0) { | |
137 | if (lin11_to_val(ret) | |
138 | < lin11_to_val(data->temp_min)) | |
139 | data->temp_min = ret; | |
140 | ret = data->temp_min; | |
141 | } | |
142 | break; | |
143 | case PMBUS_VIRT_RESET_VOUT_HISTORY: | |
144 | case PMBUS_VIRT_RESET_VIN_HISTORY: | |
145 | case PMBUS_VIRT_RESET_TEMP_HISTORY: | |
146 | ret = 0; | |
147 | break; | |
148 | default: | |
149 | ret = -ENODATA; | |
150 | break; | |
151 | } | |
152 | return ret; | |
153 | } | |
154 | ||
155 | static int ltc2978_write_word_data(struct i2c_client *client, int page, | |
156 | int reg, u16 word) | |
157 | { | |
158 | const struct pmbus_driver_info *info = pmbus_get_driver_info(client); | |
159 | struct ltc2978_data *data = to_ltc2978_data(info); | |
160 | int ret; | |
161 | ||
162 | switch (reg) { | |
163 | case PMBUS_VIRT_RESET_VOUT_HISTORY: | |
164 | data->vout_min[page] = 0xffff; | |
165 | data->vout_max[page] = 0; | |
166 | ret = pmbus_write_byte(client, page, PMBUS_CLEAR_FAULTS); | |
167 | break; | |
168 | case PMBUS_VIRT_RESET_VIN_HISTORY: | |
169 | data->vin_min = 0x7bff; | |
170 | data->vin_max = 0; | |
171 | ret = pmbus_write_byte(client, page, PMBUS_CLEAR_FAULTS); | |
172 | break; | |
173 | case PMBUS_VIRT_RESET_TEMP_HISTORY: | |
174 | data->temp_min = 0x7bff; | |
175 | data->temp_max = 0x7fff; | |
176 | ret = pmbus_write_byte(client, page, PMBUS_CLEAR_FAULTS); | |
177 | break; | |
178 | default: | |
179 | ret = -ENODATA; | |
180 | break; | |
181 | } | |
182 | return ret; | |
183 | } | |
184 | ||
185 | static const struct i2c_device_id ltc2978_id[] = { | |
186 | {"ltc2978", ltc2978}, | |
187 | {} | |
188 | }; | |
189 | MODULE_DEVICE_TABLE(i2c, ltc2978_id); | |
190 | ||
191 | static int ltc2978_probe(struct i2c_client *client, | |
192 | const struct i2c_device_id *id) | |
193 | { | |
194 | int chip_id, ret, i; | |
195 | struct ltc2978_data *data; | |
196 | struct pmbus_driver_info *info; | |
197 | ||
198 | if (!i2c_check_functionality(client->adapter, | |
199 | I2C_FUNC_SMBUS_READ_WORD_DATA)) | |
200 | return -ENODEV; | |
201 | ||
202 | data = kzalloc(sizeof(struct ltc2978_data), GFP_KERNEL); | |
203 | if (!data) | |
204 | return -ENOMEM; | |
205 | ||
206 | chip_id = i2c_smbus_read_word_data(client, LTC2978_MFR_SPECIAL_ID); | |
207 | if (chip_id < 0) { | |
208 | ret = chip_id; | |
209 | goto err_mem; | |
210 | } | |
211 | ||
212 | if (chip_id == LTC2978_ID_REV1 || chip_id == LTC2978_ID_REV2) { | |
213 | data->id = ltc2978; | |
214 | } else { | |
215 | dev_err(&client->dev, "Unsupported chip ID 0x%x\n", chip_id); | |
216 | ret = -ENODEV; | |
217 | goto err_mem; | |
218 | } | |
219 | if (data->id != id->driver_data) | |
220 | dev_warn(&client->dev, | |
221 | "Device mismatch: Configured %s, detected %s\n", | |
222 | id->name, | |
223 | ltc2978_id[data->id].name); | |
224 | ||
225 | info = &data->info; | |
226 | info->read_word_data = ltc2978_read_word_data; | |
227 | info->write_word_data = ltc2978_write_word_data; | |
228 | ||
229 | data->vout_min[0] = 0xffff; | |
230 | data->vin_min = 0x7bff; | |
231 | data->temp_min = 0x7bff; | |
232 | data->temp_max = 0x7fff; | |
233 | ||
234 | switch (id->driver_data) { | |
235 | case ltc2978: | |
236 | info->pages = 8; | |
237 | info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT | |
238 | | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT | |
239 | | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP; | |
240 | for (i = 1; i < 8; i++) { | |
241 | info->func[i] = PMBUS_HAVE_VOUT | |
242 | | PMBUS_HAVE_STATUS_VOUT; | |
243 | data->vout_min[i] = 0xffff; | |
244 | } | |
245 | break; | |
246 | default: | |
247 | ret = -ENODEV; | |
248 | goto err_mem; | |
249 | } | |
250 | ||
251 | ret = pmbus_do_probe(client, id, info); | |
252 | if (ret) | |
253 | goto err_mem; | |
254 | return 0; | |
255 | ||
256 | err_mem: | |
257 | kfree(data); | |
258 | return ret; | |
259 | } | |
260 | ||
261 | static int ltc2978_remove(struct i2c_client *client) | |
262 | { | |
263 | const struct pmbus_driver_info *info = pmbus_get_driver_info(client); | |
264 | const struct ltc2978_data *data = to_ltc2978_data(info); | |
265 | ||
266 | pmbus_do_remove(client); | |
267 | kfree(data); | |
268 | return 0; | |
269 | } | |
270 | ||
271 | /* This is the driver that will be inserted */ | |
272 | static struct i2c_driver ltc2978_driver = { | |
273 | .driver = { | |
274 | .name = "ltc2978", | |
275 | }, | |
276 | .probe = ltc2978_probe, | |
277 | .remove = ltc2978_remove, | |
278 | .id_table = ltc2978_id, | |
279 | }; | |
280 | ||
281 | static int __init ltc2978_init(void) | |
282 | { | |
283 | return i2c_add_driver(<c2978_driver); | |
284 | } | |
285 | ||
286 | static void __exit ltc2978_exit(void) | |
287 | { | |
288 | i2c_del_driver(<c2978_driver); | |
289 | } | |
290 | ||
291 | MODULE_AUTHOR("Guenter Roeck"); | |
292 | MODULE_DESCRIPTION("PMBus driver for LTC2978"); | |
293 | MODULE_LICENSE("GPL"); | |
294 | module_init(ltc2978_init); | |
295 | module_exit(ltc2978_exit); |