1/*
2 * An I2C driver for the NXP PCF2127 RTC
3 * Copyright 2013 Til-Technologies
4 *
5 * Author: Renaud Cerrato <r.cerrato@til-technologies.fr>
6 *
7 * based on the other drivers in this same directory.
8 *
9 * http://www.nxp.com/documents/data_sheet/PCF2127AT.pdf
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License version 2 as
13 * published by the Free Software Foundation.
14 */
15
16#include <linux/i2c.h>
17#include <linux/bcd.h>
18#include <linux/rtc.h>
19#include <linux/slab.h>
20#include <linux/module.h>
21#include <linux/of.h>
22
23#define PCF2127_REG_CTRL1       (0x00)  /* Control Register 1 */
24#define PCF2127_REG_CTRL2       (0x01)  /* Control Register 2 */
25
26#define PCF2127_REG_CTRL3       (0x02)  /* Control Register 3 */
27#define PCF2127_REG_CTRL3_BLF		BIT(2)
28
29#define PCF2127_REG_SC          (0x03)  /* datetime */
30#define PCF2127_REG_MN          (0x04)
31#define PCF2127_REG_HR          (0x05)
32#define PCF2127_REG_DM          (0x06)
33#define PCF2127_REG_DW          (0x07)
34#define PCF2127_REG_MO          (0x08)
35#define PCF2127_REG_YR          (0x09)
36
37#define PCF2127_OSF             BIT(7)  /* Oscillator Fail flag */
38
39static struct i2c_driver pcf2127_driver;
40
41struct pcf2127 {
42	struct rtc_device *rtc;
43};
44
45/*
46 * In the routines that deal directly with the pcf2127 hardware, we use
47 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
48 */
49static int pcf2127_get_datetime(struct i2c_client *client, struct rtc_time *tm)
50{
51	unsigned char buf[10] = { PCF2127_REG_CTRL1 };
52
53	/* read registers */
54	if (i2c_master_send(client, buf, 1) != 1 ||
55		i2c_master_recv(client, buf, sizeof(buf)) != sizeof(buf)) {
56		dev_err(&client->dev, "%s: read error\n", __func__);
57		return -EIO;
58	}
59
60	if (buf[PCF2127_REG_CTRL3] & PCF2127_REG_CTRL3_BLF)
61		dev_info(&client->dev,
62			"low voltage detected, check/replace RTC battery.\n");
63
64	if (buf[PCF2127_REG_SC] & PCF2127_OSF) {
65		/*
66		 * no need clear the flag here,
67		 * it will be cleared once the new date is saved
68		 */
69		dev_warn(&client->dev,
70			 "oscillator stop detected, date/time is not reliable\n");
71		return -EINVAL;
72	}
73
74	dev_dbg(&client->dev,
75		"%s: raw data is cr1=%02x, cr2=%02x, cr3=%02x, "
76		"sec=%02x, min=%02x, hr=%02x, "
77		"mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
78		__func__,
79		buf[0], buf[1], buf[2],
80		buf[3], buf[4], buf[5],
81		buf[6], buf[7], buf[8], buf[9]);
82
83
84	tm->tm_sec = bcd2bin(buf[PCF2127_REG_SC] & 0x7F);
85	tm->tm_min = bcd2bin(buf[PCF2127_REG_MN] & 0x7F);
86	tm->tm_hour = bcd2bin(buf[PCF2127_REG_HR] & 0x3F); /* rtc hr 0-23 */
87	tm->tm_mday = bcd2bin(buf[PCF2127_REG_DM] & 0x3F);
88	tm->tm_wday = buf[PCF2127_REG_DW] & 0x07;
89	tm->tm_mon = bcd2bin(buf[PCF2127_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
90	tm->tm_year = bcd2bin(buf[PCF2127_REG_YR]);
91	if (tm->tm_year < 70)
92		tm->tm_year += 100;	/* assume we are in 1970...2069 */
93
94	dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
95		"mday=%d, mon=%d, year=%d, wday=%d\n",
96		__func__,
97		tm->tm_sec, tm->tm_min, tm->tm_hour,
98		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
99
100	return rtc_valid_tm(tm);
101}
102
103static int pcf2127_set_datetime(struct i2c_client *client, struct rtc_time *tm)
104{
105	unsigned char buf[8];
106	int i = 0, err;
107
108	dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
109		"mday=%d, mon=%d, year=%d, wday=%d\n",
110		__func__,
111		tm->tm_sec, tm->tm_min, tm->tm_hour,
112		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
113
114	/* start register address */
115	buf[i++] = PCF2127_REG_SC;
116
117	/* hours, minutes and seconds */
118	buf[i++] = bin2bcd(tm->tm_sec);	/* this will also clear OSF flag */
119	buf[i++] = bin2bcd(tm->tm_min);
120	buf[i++] = bin2bcd(tm->tm_hour);
121	buf[i++] = bin2bcd(tm->tm_mday);
122	buf[i++] = tm->tm_wday & 0x07;
123
124	/* month, 1 - 12 */
125	buf[i++] = bin2bcd(tm->tm_mon + 1);
126
127	/* year */
128	buf[i++] = bin2bcd(tm->tm_year % 100);
129
130	/* write register's data */
131	err = i2c_master_send(client, buf, i);
132	if (err != i) {
133		dev_err(&client->dev,
134			"%s: err=%d", __func__, err);
135		return -EIO;
136	}
137
138	return 0;
139}
140
141#ifdef CONFIG_RTC_INTF_DEV
142static int pcf2127_rtc_ioctl(struct device *dev,
143				unsigned int cmd, unsigned long arg)
144{
145	struct i2c_client *client = to_i2c_client(dev);
146	unsigned char buf = PCF2127_REG_CTRL3;
147	int touser;
148	int ret;
149
150	switch (cmd) {
151	case RTC_VL_READ:
152		ret = i2c_master_send(client, &buf, 1);
153		if (!ret)
154			ret = -EIO;
155		if (ret < 0)
156			return ret;
157
158		ret = i2c_master_recv(client, &buf, 1);
159		if (!ret)
160			ret = -EIO;
161		if (ret < 0)
162			return ret;
163
164		touser = buf & PCF2127_REG_CTRL3_BLF ? 1 : 0;
165
166		if (copy_to_user((void __user *)arg, &touser, sizeof(int)))
167			return -EFAULT;
168		return 0;
169	default:
170		return -ENOIOCTLCMD;
171	}
172}
173#else
174#define pcf2127_rtc_ioctl NULL
175#endif
176
177static int pcf2127_rtc_read_time(struct device *dev, struct rtc_time *tm)
178{
179	return pcf2127_get_datetime(to_i2c_client(dev), tm);
180}
181
182static int pcf2127_rtc_set_time(struct device *dev, struct rtc_time *tm)
183{
184	return pcf2127_set_datetime(to_i2c_client(dev), tm);
185}
186
187static const struct rtc_class_ops pcf2127_rtc_ops = {
188	.ioctl		= pcf2127_rtc_ioctl,
189	.read_time	= pcf2127_rtc_read_time,
190	.set_time	= pcf2127_rtc_set_time,
191};
192
193static int pcf2127_probe(struct i2c_client *client,
194				const struct i2c_device_id *id)
195{
196	struct pcf2127 *pcf2127;
197
198	dev_dbg(&client->dev, "%s\n", __func__);
199
200	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
201		return -ENODEV;
202
203	pcf2127 = devm_kzalloc(&client->dev, sizeof(struct pcf2127),
204				GFP_KERNEL);
205	if (!pcf2127)
206		return -ENOMEM;
207
208	i2c_set_clientdata(client, pcf2127);
209
210	pcf2127->rtc = devm_rtc_device_register(&client->dev,
211				pcf2127_driver.driver.name,
212				&pcf2127_rtc_ops, THIS_MODULE);
213
214	return PTR_ERR_OR_ZERO(pcf2127->rtc);
215}
216
217static const struct i2c_device_id pcf2127_id[] = {
218	{ "pcf2127", 0 },
219	{ }
220};
221MODULE_DEVICE_TABLE(i2c, pcf2127_id);
222
223#ifdef CONFIG_OF
224static const struct of_device_id pcf2127_of_match[] = {
225	{ .compatible = "nxp,pcf2127" },
226	{}
227};
228MODULE_DEVICE_TABLE(of, pcf2127_of_match);
229#endif
230
231static struct i2c_driver pcf2127_driver = {
232	.driver		= {
233		.name	= "rtc-pcf2127",
234		.of_match_table = of_match_ptr(pcf2127_of_match),
235	},
236	.probe		= pcf2127_probe,
237	.id_table	= pcf2127_id,
238};
239
240module_i2c_driver(pcf2127_driver);
241
242MODULE_AUTHOR("Renaud Cerrato <r.cerrato@til-technologies.fr>");
243MODULE_DESCRIPTION("NXP PCF2127 RTC driver");
244MODULE_LICENSE("GPL v2");
245