Root/drivers/rtc/rtc-rv3029c2.c

1/*
2 * Micro Crystal RV-3029C2 rtc class driver
3 *
4 * Author: Gregory Hermant <gregory.hermant@calao-systems.com>
5 *
6 * based on previously existing rtc class drivers
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 *
12 * NOTE: Currently this driver only supports the bare minimum for read
13 * and write the RTC and alarms. The extra features provided by this chip
14 * (trickle charger, eeprom, T° compensation) are unavailable.
15 */
16
17#include <linux/module.h>
18#include <linux/i2c.h>
19#include <linux/bcd.h>
20#include <linux/rtc.h>
21
22/* Register map */
23/* control section */
24#define RV3029C2_ONOFF_CTRL 0x00
25#define RV3029C2_IRQ_CTRL 0x01
26#define RV3029C2_IRQ_CTRL_AIE (1 << 0)
27#define RV3029C2_IRQ_FLAGS 0x02
28#define RV3029C2_IRQ_FLAGS_AF (1 << 0)
29#define RV3029C2_STATUS 0x03
30#define RV3029C2_STATUS_VLOW1 (1 << 2)
31#define RV3029C2_STATUS_VLOW2 (1 << 3)
32#define RV3029C2_STATUS_SR (1 << 4)
33#define RV3029C2_STATUS_PON (1 << 5)
34#define RV3029C2_STATUS_EEBUSY (1 << 7)
35#define RV3029C2_RST_CTRL 0x04
36#define RV3029C2_CONTROL_SECTION_LEN 0x05
37
38/* watch section */
39#define RV3029C2_W_SEC 0x08
40#define RV3029C2_W_MINUTES 0x09
41#define RV3029C2_W_HOURS 0x0A
42#define RV3029C2_REG_HR_12_24 (1<<6) /* 24h/12h mode */
43#define RV3029C2_REG_HR_PM (1<<5) /* PM/AM bit in 12h mode */
44#define RV3029C2_W_DATE 0x0B
45#define RV3029C2_W_DAYS 0x0C
46#define RV3029C2_W_MONTHS 0x0D
47#define RV3029C2_W_YEARS 0x0E
48#define RV3029C2_WATCH_SECTION_LEN 0x07
49
50/* alarm section */
51#define RV3029C2_A_SC 0x10
52#define RV3029C2_A_MN 0x11
53#define RV3029C2_A_HR 0x12
54#define RV3029C2_A_DT 0x13
55#define RV3029C2_A_DW 0x14
56#define RV3029C2_A_MO 0x15
57#define RV3029C2_A_YR 0x16
58#define RV3029C2_ALARM_SECTION_LEN 0x07
59
60/* timer section */
61#define RV3029C2_TIMER_LOW 0x18
62#define RV3029C2_TIMER_HIGH 0x19
63
64/* temperature section */
65#define RV3029C2_TEMP_PAGE 0x20
66
67/* eeprom data section */
68#define RV3029C2_E2P_EEDATA1 0x28
69#define RV3029C2_E2P_EEDATA2 0x29
70
71/* eeprom control section */
72#define RV3029C2_CONTROL_E2P_EECTRL 0x30
73#define RV3029C2_TRICKLE_1K (1<<0) /* 1K resistance */
74#define RV3029C2_TRICKLE_5K (1<<1) /* 5K resistance */
75#define RV3029C2_TRICKLE_20K (1<<2) /* 20K resistance */
76#define RV3029C2_TRICKLE_80K (1<<3) /* 80K resistance */
77#define RV3029C2_CONTROL_E2P_XTALOFFSET 0x31
78#define RV3029C2_CONTROL_E2P_QCOEF 0x32
79#define RV3029C2_CONTROL_E2P_TURNOVER 0x33
80
81/* user ram section */
82#define RV3029C2_USR1_RAM_PAGE 0x38
83#define RV3029C2_USR1_SECTION_LEN 0x04
84#define RV3029C2_USR2_RAM_PAGE 0x3C
85#define RV3029C2_USR2_SECTION_LEN 0x04
86
87static int
88rv3029c2_i2c_read_regs(struct i2c_client *client, u8 reg, u8 *buf,
89    unsigned len)
90{
91    int ret;
92
93    if ((reg > RV3029C2_USR1_RAM_PAGE + 7) ||
94        (reg + len > RV3029C2_USR1_RAM_PAGE + 8))
95        return -EINVAL;
96
97    ret = i2c_smbus_read_i2c_block_data(client, reg, len, buf);
98    if (ret < 0)
99        return ret;
100    if (ret < len)
101        return -EIO;
102    return 0;
103}
104
105static int
106rv3029c2_i2c_write_regs(struct i2c_client *client, u8 reg, u8 const buf[],
107            unsigned len)
108{
109    if ((reg > RV3029C2_USR1_RAM_PAGE + 7) ||
110        (reg + len > RV3029C2_USR1_RAM_PAGE + 8))
111        return -EINVAL;
112
113    return i2c_smbus_write_i2c_block_data(client, reg, len, buf);
114}
115
116static int
117rv3029c2_i2c_get_sr(struct i2c_client *client, u8 *buf)
118{
119    int ret = rv3029c2_i2c_read_regs(client, RV3029C2_STATUS, buf, 1);
120
121    if (ret < 0)
122        return -EIO;
123    dev_dbg(&client->dev, "status = 0x%.2x (%d)\n", buf[0], buf[0]);
124    return 0;
125}
126
127static int
128rv3029c2_i2c_set_sr(struct i2c_client *client, u8 val)
129{
130    u8 buf[1];
131    int sr;
132
133    buf[0] = val;
134    sr = rv3029c2_i2c_write_regs(client, RV3029C2_STATUS, buf, 1);
135    dev_dbg(&client->dev, "status = 0x%.2x (%d)\n", buf[0], buf[0]);
136    if (sr < 0)
137        return -EIO;
138    return 0;
139}
140
141static int
142rv3029c2_i2c_read_time(struct i2c_client *client, struct rtc_time *tm)
143{
144    u8 buf[1];
145    int ret;
146    u8 regs[RV3029C2_WATCH_SECTION_LEN] = { 0, };
147
148    ret = rv3029c2_i2c_get_sr(client, buf);
149    if (ret < 0) {
150        dev_err(&client->dev, "%s: reading SR failed\n", __func__);
151        return -EIO;
152    }
153
154    ret = rv3029c2_i2c_read_regs(client, RV3029C2_W_SEC , regs,
155                    RV3029C2_WATCH_SECTION_LEN);
156    if (ret < 0) {
157        dev_err(&client->dev, "%s: reading RTC section failed\n",
158            __func__);
159        return ret;
160    }
161
162    tm->tm_sec = bcd2bin(regs[RV3029C2_W_SEC-RV3029C2_W_SEC]);
163    tm->tm_min = bcd2bin(regs[RV3029C2_W_MINUTES-RV3029C2_W_SEC]);
164
165    /* HR field has a more complex interpretation */
166    {
167        const u8 _hr = regs[RV3029C2_W_HOURS-RV3029C2_W_SEC];
168        if (_hr & RV3029C2_REG_HR_12_24) {
169            /* 12h format */
170            tm->tm_hour = bcd2bin(_hr & 0x1f);
171            if (_hr & RV3029C2_REG_HR_PM) /* PM flag set */
172                tm->tm_hour += 12;
173        } else /* 24h format */
174            tm->tm_hour = bcd2bin(_hr & 0x3f);
175    }
176
177    tm->tm_mday = bcd2bin(regs[RV3029C2_W_DATE-RV3029C2_W_SEC]);
178    tm->tm_mon = bcd2bin(regs[RV3029C2_W_MONTHS-RV3029C2_W_SEC]) - 1;
179    tm->tm_year = bcd2bin(regs[RV3029C2_W_YEARS-RV3029C2_W_SEC]) + 100;
180    tm->tm_wday = bcd2bin(regs[RV3029C2_W_DAYS-RV3029C2_W_SEC]) - 1;
181
182    return 0;
183}
184
185static int rv3029c2_rtc_read_time(struct device *dev, struct rtc_time *tm)
186{
187    return rv3029c2_i2c_read_time(to_i2c_client(dev), tm);
188}
189
190static int
191rv3029c2_i2c_read_alarm(struct i2c_client *client, struct rtc_wkalrm *alarm)
192{
193    struct rtc_time *const tm = &alarm->time;
194    int ret;
195    u8 regs[8];
196
197    ret = rv3029c2_i2c_get_sr(client, regs);
198    if (ret < 0) {
199        dev_err(&client->dev, "%s: reading SR failed\n", __func__);
200        return -EIO;
201    }
202
203    ret = rv3029c2_i2c_read_regs(client, RV3029C2_A_SC, regs,
204                    RV3029C2_ALARM_SECTION_LEN);
205
206    if (ret < 0) {
207        dev_err(&client->dev, "%s: reading alarm section failed\n",
208            __func__);
209        return ret;
210    }
211
212    tm->tm_sec = bcd2bin(regs[RV3029C2_A_SC-RV3029C2_A_SC] & 0x7f);
213    tm->tm_min = bcd2bin(regs[RV3029C2_A_MN-RV3029C2_A_SC] & 0x7f);
214    tm->tm_hour = bcd2bin(regs[RV3029C2_A_HR-RV3029C2_A_SC] & 0x3f);
215    tm->tm_mday = bcd2bin(regs[RV3029C2_A_DT-RV3029C2_A_SC] & 0x3f);
216    tm->tm_mon = bcd2bin(regs[RV3029C2_A_MO-RV3029C2_A_SC] & 0x1f) - 1;
217    tm->tm_year = bcd2bin(regs[RV3029C2_A_YR-RV3029C2_A_SC] & 0x7f) + 100;
218    tm->tm_wday = bcd2bin(regs[RV3029C2_A_DW-RV3029C2_A_SC] & 0x07) - 1;
219
220    return 0;
221}
222
223static int
224rv3029c2_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
225{
226    return rv3029c2_i2c_read_alarm(to_i2c_client(dev), alarm);
227}
228
229static int rv3029c2_rtc_i2c_alarm_set_irq(struct i2c_client *client,
230                    int enable)
231{
232    int ret;
233    u8 buf[1];
234
235    /* enable AIE irq */
236    ret = rv3029c2_i2c_read_regs(client, RV3029C2_IRQ_CTRL, buf, 1);
237    if (ret < 0) {
238        dev_err(&client->dev, "can't read INT reg\n");
239        return ret;
240    }
241    if (enable)
242        buf[0] |= RV3029C2_IRQ_CTRL_AIE;
243    else
244        buf[0] &= ~RV3029C2_IRQ_CTRL_AIE;
245
246    ret = rv3029c2_i2c_write_regs(client, RV3029C2_IRQ_CTRL, buf, 1);
247    if (ret < 0) {
248        dev_err(&client->dev, "can't set INT reg\n");
249        return ret;
250    }
251
252    return 0;
253}
254
255static int rv3029c2_rtc_i2c_set_alarm(struct i2c_client *client,
256                    struct rtc_wkalrm *alarm)
257{
258    struct rtc_time *const tm = &alarm->time;
259    int ret;
260    u8 regs[8];
261
262    /*
263     * The clock has an 8 bit wide bcd-coded register (they never learn)
264     * for the year. tm_year is an offset from 1900 and we are interested
265     * in the 2000-2099 range, so any value less than 100 is invalid.
266    */
267    if (tm->tm_year < 100)
268        return -EINVAL;
269
270    ret = rv3029c2_i2c_get_sr(client, regs);
271    if (ret < 0) {
272        dev_err(&client->dev, "%s: reading SR failed\n", __func__);
273        return -EIO;
274    }
275    regs[RV3029C2_A_SC-RV3029C2_A_SC] = bin2bcd(tm->tm_sec & 0x7f);
276    regs[RV3029C2_A_MN-RV3029C2_A_SC] = bin2bcd(tm->tm_min & 0x7f);
277    regs[RV3029C2_A_HR-RV3029C2_A_SC] = bin2bcd(tm->tm_hour & 0x3f);
278    regs[RV3029C2_A_DT-RV3029C2_A_SC] = bin2bcd(tm->tm_mday & 0x3f);
279    regs[RV3029C2_A_MO-RV3029C2_A_SC] = bin2bcd((tm->tm_mon & 0x1f) - 1);
280    regs[RV3029C2_A_DW-RV3029C2_A_SC] = bin2bcd((tm->tm_wday & 7) - 1);
281    regs[RV3029C2_A_YR-RV3029C2_A_SC] = bin2bcd((tm->tm_year & 0x7f) - 100);
282
283    ret = rv3029c2_i2c_write_regs(client, RV3029C2_A_SC, regs,
284                    RV3029C2_ALARM_SECTION_LEN);
285    if (ret < 0)
286        return ret;
287
288    if (alarm->enabled) {
289        u8 buf[1];
290
291        /* clear AF flag */
292        ret = rv3029c2_i2c_read_regs(client, RV3029C2_IRQ_FLAGS,
293                        buf, 1);
294        if (ret < 0) {
295            dev_err(&client->dev, "can't read alarm flag\n");
296            return ret;
297        }
298        buf[0] &= ~RV3029C2_IRQ_FLAGS_AF;
299        ret = rv3029c2_i2c_write_regs(client, RV3029C2_IRQ_FLAGS,
300                        buf, 1);
301        if (ret < 0) {
302            dev_err(&client->dev, "can't set alarm flag\n");
303            return ret;
304        }
305        /* enable AIE irq */
306        ret = rv3029c2_rtc_i2c_alarm_set_irq(client, 1);
307        if (ret)
308            return ret;
309
310        dev_dbg(&client->dev, "alarm IRQ armed\n");
311    } else {
312        /* disable AIE irq */
313        ret = rv3029c2_rtc_i2c_alarm_set_irq(client, 1);
314        if (ret)
315            return ret;
316
317        dev_dbg(&client->dev, "alarm IRQ disabled\n");
318    }
319
320    return 0;
321}
322
323static int rv3029c2_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
324{
325    return rv3029c2_rtc_i2c_set_alarm(to_i2c_client(dev), alarm);
326}
327
328static int
329rv3029c2_i2c_set_time(struct i2c_client *client, struct rtc_time const *tm)
330{
331    u8 regs[8];
332    int ret;
333
334    /*
335     * The clock has an 8 bit wide bcd-coded register (they never learn)
336     * for the year. tm_year is an offset from 1900 and we are interested
337     * in the 2000-2099 range, so any value less than 100 is invalid.
338    */
339    if (tm->tm_year < 100)
340        return -EINVAL;
341
342    regs[RV3029C2_W_SEC-RV3029C2_W_SEC] = bin2bcd(tm->tm_sec);
343    regs[RV3029C2_W_MINUTES-RV3029C2_W_SEC] = bin2bcd(tm->tm_min);
344    regs[RV3029C2_W_HOURS-RV3029C2_W_SEC] = bin2bcd(tm->tm_hour);
345    regs[RV3029C2_W_DATE-RV3029C2_W_SEC] = bin2bcd(tm->tm_mday);
346    regs[RV3029C2_W_MONTHS-RV3029C2_W_SEC] = bin2bcd(tm->tm_mon+1);
347    regs[RV3029C2_W_DAYS-RV3029C2_W_SEC] = bin2bcd((tm->tm_wday & 7)+1);
348    regs[RV3029C2_W_YEARS-RV3029C2_W_SEC] = bin2bcd(tm->tm_year - 100);
349
350    ret = rv3029c2_i2c_write_regs(client, RV3029C2_W_SEC, regs,
351                    RV3029C2_WATCH_SECTION_LEN);
352    if (ret < 0)
353        return ret;
354
355    ret = rv3029c2_i2c_get_sr(client, regs);
356    if (ret < 0) {
357        dev_err(&client->dev, "%s: reading SR failed\n", __func__);
358        return ret;
359    }
360    /* clear PON bit */
361    ret = rv3029c2_i2c_set_sr(client, (regs[0] & ~RV3029C2_STATUS_PON));
362    if (ret < 0) {
363        dev_err(&client->dev, "%s: reading SR failed\n", __func__);
364        return ret;
365    }
366
367    return 0;
368}
369
370static int rv3029c2_rtc_set_time(struct device *dev, struct rtc_time *tm)
371{
372    return rv3029c2_i2c_set_time(to_i2c_client(dev), tm);
373}
374
375static const struct rtc_class_ops rv3029c2_rtc_ops = {
376    .read_time = rv3029c2_rtc_read_time,
377    .set_time = rv3029c2_rtc_set_time,
378    .read_alarm = rv3029c2_rtc_read_alarm,
379    .set_alarm = rv3029c2_rtc_set_alarm,
380};
381
382static struct i2c_device_id rv3029c2_id[] = {
383    { "rv3029c2", 0 },
384    { }
385};
386MODULE_DEVICE_TABLE(i2c, rv3029c2_id);
387
388static int __devinit
389rv3029c2_probe(struct i2c_client *client, const struct i2c_device_id *id)
390{
391    struct rtc_device *rtc;
392    int rc = 0;
393    u8 buf[1];
394
395    if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_EMUL))
396        return -ENODEV;
397
398    rtc = rtc_device_register(client->name,
399                &client->dev, &rv3029c2_rtc_ops,
400                THIS_MODULE);
401
402    if (IS_ERR(rtc))
403        return PTR_ERR(rtc);
404
405    i2c_set_clientdata(client, rtc);
406
407    rc = rv3029c2_i2c_get_sr(client, buf);
408    if (rc < 0) {
409        dev_err(&client->dev, "reading status failed\n");
410        goto exit_unregister;
411    }
412
413    return 0;
414
415exit_unregister:
416    rtc_device_unregister(rtc);
417
418    return rc;
419}
420
421static int __devexit rv3029c2_remove(struct i2c_client *client)
422{
423    struct rtc_device *rtc = i2c_get_clientdata(client);
424
425    rtc_device_unregister(rtc);
426
427    return 0;
428}
429
430static struct i2c_driver rv3029c2_driver = {
431    .driver = {
432        .name = "rtc-rv3029c2",
433    },
434    .probe = rv3029c2_probe,
435    .remove = __devexit_p(rv3029c2_remove),
436    .id_table = rv3029c2_id,
437};
438
439module_i2c_driver(rv3029c2_driver);
440
441MODULE_AUTHOR("Gregory Hermant <gregory.hermant@calao-systems.com>");
442MODULE_DESCRIPTION("Micro Crystal RV3029C2 RTC driver");
443MODULE_LICENSE("GPL");
444

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