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Philippe De Muyter4d61ff62015-05-05 16:23:44 -07001/*
2 * A driver for the I2C members of the Abracon AB x8xx RTC family,
3 * and compatible: AB 1805 and AB 0805
4 *
5 * Copyright 2014-2015 Macq S.A.
6 *
7 * Author: Philippe De Muyter <phdm@macqel.be>
8 * Author: Alexandre Belloni <alexandre.belloni@free-electrons.com>
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
13 *
14 */
15
16#include <linux/bcd.h>
17#include <linux/i2c.h>
18#include <linux/module.h>
19#include <linux/rtc.h>
20
21#define ABX8XX_REG_HTH 0x00
22#define ABX8XX_REG_SC 0x01
23#define ABX8XX_REG_MN 0x02
24#define ABX8XX_REG_HR 0x03
25#define ABX8XX_REG_DA 0x04
26#define ABX8XX_REG_MO 0x05
27#define ABX8XX_REG_YR 0x06
28#define ABX8XX_REG_WD 0x07
29
30#define ABX8XX_REG_CTRL1 0x10
Mitja Spes5f1b2f72015-09-02 10:02:29 +020031#define ABX8XX_CTRL_WRITE BIT(0)
Philippe De Muyter4d61ff62015-05-05 16:23:44 -070032#define ABX8XX_CTRL_12_24 BIT(6)
33
34#define ABX8XX_REG_CFG_KEY 0x1f
35#define ABX8XX_CFG_KEY_MISC 0x9d
36
37#define ABX8XX_REG_ID0 0x28
38
39#define ABX8XX_REG_TRICKLE 0x20
40#define ABX8XX_TRICKLE_CHARGE_ENABLE 0xa0
41#define ABX8XX_TRICKLE_STANDARD_DIODE 0x8
42#define ABX8XX_TRICKLE_SCHOTTKY_DIODE 0x4
43
44static u8 trickle_resistors[] = {0, 3, 6, 11};
45
46enum abx80x_chip {AB0801, AB0803, AB0804, AB0805,
47 AB1801, AB1803, AB1804, AB1805, ABX80X};
48
49struct abx80x_cap {
50 u16 pn;
51 bool has_tc;
52};
53
54static struct abx80x_cap abx80x_caps[] = {
55 [AB0801] = {.pn = 0x0801},
56 [AB0803] = {.pn = 0x0803},
57 [AB0804] = {.pn = 0x0804, .has_tc = true},
58 [AB0805] = {.pn = 0x0805, .has_tc = true},
59 [AB1801] = {.pn = 0x1801},
60 [AB1803] = {.pn = 0x1803},
61 [AB1804] = {.pn = 0x1804, .has_tc = true},
62 [AB1805] = {.pn = 0x1805, .has_tc = true},
63 [ABX80X] = {.pn = 0}
64};
65
66static struct i2c_driver abx80x_driver;
67
68static int abx80x_enable_trickle_charger(struct i2c_client *client,
69 u8 trickle_cfg)
70{
71 int err;
72
73 /*
74 * Write the configuration key register to enable access to the Trickle
75 * register
76 */
77 err = i2c_smbus_write_byte_data(client, ABX8XX_REG_CFG_KEY,
78 ABX8XX_CFG_KEY_MISC);
79 if (err < 0) {
80 dev_err(&client->dev, "Unable to write configuration key\n");
81 return -EIO;
82 }
83
84 err = i2c_smbus_write_byte_data(client, ABX8XX_REG_TRICKLE,
85 ABX8XX_TRICKLE_CHARGE_ENABLE |
86 trickle_cfg);
87 if (err < 0) {
88 dev_err(&client->dev, "Unable to write trickle register\n");
89 return -EIO;
90 }
91
92 return 0;
93}
94
95static int abx80x_rtc_read_time(struct device *dev, struct rtc_time *tm)
96{
97 struct i2c_client *client = to_i2c_client(dev);
98 unsigned char buf[8];
99 int err;
100
101 err = i2c_smbus_read_i2c_block_data(client, ABX8XX_REG_HTH,
102 sizeof(buf), buf);
103 if (err < 0) {
104 dev_err(&client->dev, "Unable to read date\n");
105 return -EIO;
106 }
107
108 tm->tm_sec = bcd2bin(buf[ABX8XX_REG_SC] & 0x7F);
109 tm->tm_min = bcd2bin(buf[ABX8XX_REG_MN] & 0x7F);
110 tm->tm_hour = bcd2bin(buf[ABX8XX_REG_HR] & 0x3F);
111 tm->tm_wday = buf[ABX8XX_REG_WD] & 0x7;
112 tm->tm_mday = bcd2bin(buf[ABX8XX_REG_DA] & 0x3F);
113 tm->tm_mon = bcd2bin(buf[ABX8XX_REG_MO] & 0x1F) - 1;
114 tm->tm_year = bcd2bin(buf[ABX8XX_REG_YR]) + 100;
115
116 err = rtc_valid_tm(tm);
117 if (err < 0)
118 dev_err(&client->dev, "retrieved date/time is not valid.\n");
119
120 return err;
121}
122
123static int abx80x_rtc_set_time(struct device *dev, struct rtc_time *tm)
124{
125 struct i2c_client *client = to_i2c_client(dev);
126 unsigned char buf[8];
127 int err;
128
129 if (tm->tm_year < 100)
130 return -EINVAL;
131
132 buf[ABX8XX_REG_HTH] = 0;
133 buf[ABX8XX_REG_SC] = bin2bcd(tm->tm_sec);
134 buf[ABX8XX_REG_MN] = bin2bcd(tm->tm_min);
135 buf[ABX8XX_REG_HR] = bin2bcd(tm->tm_hour);
136 buf[ABX8XX_REG_DA] = bin2bcd(tm->tm_mday);
137 buf[ABX8XX_REG_MO] = bin2bcd(tm->tm_mon + 1);
138 buf[ABX8XX_REG_YR] = bin2bcd(tm->tm_year - 100);
139 buf[ABX8XX_REG_WD] = tm->tm_wday;
140
141 err = i2c_smbus_write_i2c_block_data(client, ABX8XX_REG_HTH,
142 sizeof(buf), buf);
143 if (err < 0) {
144 dev_err(&client->dev, "Unable to write to date registers\n");
145 return -EIO;
146 }
147
148 return 0;
149}
150
151static const struct rtc_class_ops abx80x_rtc_ops = {
152 .read_time = abx80x_rtc_read_time,
153 .set_time = abx80x_rtc_set_time,
154};
155
156static int abx80x_dt_trickle_cfg(struct device_node *np)
157{
158 const char *diode;
159 int trickle_cfg = 0;
160 int i, ret;
161 u32 tmp;
162
163 ret = of_property_read_string(np, "abracon,tc-diode", &diode);
164 if (ret)
165 return ret;
166
167 if (!strcmp(diode, "standard"))
168 trickle_cfg |= ABX8XX_TRICKLE_STANDARD_DIODE;
169 else if (!strcmp(diode, "schottky"))
170 trickle_cfg |= ABX8XX_TRICKLE_SCHOTTKY_DIODE;
171 else
172 return -EINVAL;
173
174 ret = of_property_read_u32(np, "abracon,tc-resistor", &tmp);
175 if (ret)
176 return ret;
177
178 for (i = 0; i < sizeof(trickle_resistors); i++)
179 if (trickle_resistors[i] == tmp)
180 break;
181
182 if (i == sizeof(trickle_resistors))
183 return -EINVAL;
184
185 return (trickle_cfg | i);
186}
187
188static int abx80x_probe(struct i2c_client *client,
189 const struct i2c_device_id *id)
190{
191 struct device_node *np = client->dev.of_node;
192 struct rtc_device *rtc;
193 int i, data, err, trickle_cfg = -EINVAL;
194 char buf[7];
195 unsigned int part = id->driver_data;
196 unsigned int partnumber;
197 unsigned int majrev, minrev;
198 unsigned int lot;
199 unsigned int wafer;
200 unsigned int uid;
201
202 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
203 return -ENODEV;
204
205 err = i2c_smbus_read_i2c_block_data(client, ABX8XX_REG_ID0,
206 sizeof(buf), buf);
207 if (err < 0) {
208 dev_err(&client->dev, "Unable to read partnumber\n");
209 return -EIO;
210 }
211
212 partnumber = (buf[0] << 8) | buf[1];
213 majrev = buf[2] >> 3;
214 minrev = buf[2] & 0x7;
215 lot = ((buf[4] & 0x80) << 2) | ((buf[6] & 0x80) << 1) | buf[3];
216 uid = ((buf[4] & 0x7f) << 8) | buf[5];
217 wafer = (buf[6] & 0x7c) >> 2;
218 dev_info(&client->dev, "model %04x, revision %u.%u, lot %x, wafer %x, uid %x\n",
219 partnumber, majrev, minrev, lot, wafer, uid);
220
221 data = i2c_smbus_read_byte_data(client, ABX8XX_REG_CTRL1);
222 if (data < 0) {
223 dev_err(&client->dev, "Unable to read control register\n");
224 return -EIO;
225 }
226
227 err = i2c_smbus_write_byte_data(client, ABX8XX_REG_CTRL1,
228 ((data & ~ABX8XX_CTRL_12_24) |
229 ABX8XX_CTRL_WRITE));
230 if (err < 0) {
231 dev_err(&client->dev, "Unable to write control register\n");
232 return -EIO;
233 }
234
235 /* part autodetection */
236 if (part == ABX80X) {
237 for (i = 0; abx80x_caps[i].pn; i++)
238 if (partnumber == abx80x_caps[i].pn)
239 break;
240 if (abx80x_caps[i].pn == 0) {
241 dev_err(&client->dev, "Unknown part: %04x\n",
242 partnumber);
243 return -EINVAL;
244 }
245 part = i;
246 }
247
248 if (partnumber != abx80x_caps[part].pn) {
249 dev_err(&client->dev, "partnumber mismatch %04x != %04x\n",
250 partnumber, abx80x_caps[part].pn);
251 return -EINVAL;
252 }
253
254 if (np && abx80x_caps[part].has_tc)
255 trickle_cfg = abx80x_dt_trickle_cfg(np);
256
257 if (trickle_cfg > 0) {
258 dev_info(&client->dev, "Enabling trickle charger: %02x\n",
259 trickle_cfg);
260 abx80x_enable_trickle_charger(client, trickle_cfg);
261 }
262
263 rtc = devm_rtc_device_register(&client->dev, abx80x_driver.driver.name,
264 &abx80x_rtc_ops, THIS_MODULE);
265
266 if (IS_ERR(rtc))
267 return PTR_ERR(rtc);
268
269 i2c_set_clientdata(client, rtc);
270
271 return 0;
272}
273
274static int abx80x_remove(struct i2c_client *client)
275{
276 return 0;
277}
278
279static const struct i2c_device_id abx80x_id[] = {
280 { "abx80x", ABX80X },
281 { "ab0801", AB0801 },
282 { "ab0803", AB0803 },
283 { "ab0804", AB0804 },
284 { "ab0805", AB0805 },
285 { "ab1801", AB1801 },
286 { "ab1803", AB1803 },
287 { "ab1804", AB1804 },
288 { "ab1805", AB1805 },
289 { }
290};
291MODULE_DEVICE_TABLE(i2c, abx80x_id);
292
293static struct i2c_driver abx80x_driver = {
294 .driver = {
295 .name = "rtc-abx80x",
296 },
297 .probe = abx80x_probe,
298 .remove = abx80x_remove,
299 .id_table = abx80x_id,
300};
301
302module_i2c_driver(abx80x_driver);
303
304MODULE_AUTHOR("Philippe De Muyter <phdm@macqel.be>");
305MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@free-electrons.com>");
306MODULE_DESCRIPTION("Abracon ABX80X RTC driver");
307MODULE_LICENSE("GPL v2");