1/*
2 * An I2C driver for the PCF85063 RTC
3 * Copyright 2014 Rose Technology
4 *
5 * Author: Søren Andersen <san@rosetechnology.dk>
6 * Maintainers: http://www.nslu2-linux.org/
7 *
8 * based on the other drivers in this same directory.
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#include <linux/i2c.h>
15#include <linux/bcd.h>
16#include <linux/rtc.h>
17#include <linux/module.h>
18
19#define DRV_VERSION "0.0.1"
20
21#define PCF85063_REG_CTRL1		0x00 /* status */
22#define PCF85063_REG_CTRL2		0x01
23
24#define PCF85063_REG_SC			0x04 /* datetime */
25#define PCF85063_REG_MN			0x05
26#define PCF85063_REG_HR			0x06
27#define PCF85063_REG_DM			0x07
28#define PCF85063_REG_DW			0x08
29#define PCF85063_REG_MO			0x09
30#define PCF85063_REG_YR			0x0A
31
32#define PCF85063_MO_C			0x80 /* century */
33
34static struct i2c_driver pcf85063_driver;
35
36struct pcf85063 {
37	struct rtc_device *rtc;
38	int c_polarity;	/* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */
39	int voltage_low; /* indicates if a low_voltage was detected */
40};
41
42/*
43 * In the routines that deal directly with the pcf85063 hardware, we use
44 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
45 */
46static int pcf85063_get_datetime(struct i2c_client *client, struct rtc_time *tm)
47{
48	struct pcf85063 *pcf85063 = i2c_get_clientdata(client);
49	unsigned char buf[13] = { PCF85063_REG_CTRL1 };
50	struct i2c_msg msgs[] = {
51		{/* setup read ptr */
52			.addr = client->addr,
53			.len = 1,
54			.buf = buf
55		},
56		{/* read status + date */
57			.addr = client->addr,
58			.flags = I2C_M_RD,
59			.len = 13,
60			.buf = buf
61		},
62	};
63
64	/* read registers */
65	if ((i2c_transfer(client->adapter, msgs, 2)) != 2) {
66		dev_err(&client->dev, "%s: read error\n", __func__);
67		return -EIO;
68	}
69
70	tm->tm_sec = bcd2bin(buf[PCF85063_REG_SC] & 0x7F);
71	tm->tm_min = bcd2bin(buf[PCF85063_REG_MN] & 0x7F);
72	tm->tm_hour = bcd2bin(buf[PCF85063_REG_HR] & 0x3F); /* rtc hr 0-23 */
73	tm->tm_mday = bcd2bin(buf[PCF85063_REG_DM] & 0x3F);
74	tm->tm_wday = buf[PCF85063_REG_DW] & 0x07;
75	tm->tm_mon = bcd2bin(buf[PCF85063_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
76	tm->tm_year = bcd2bin(buf[PCF85063_REG_YR]);
77	if (tm->tm_year < 70)
78		tm->tm_year += 100;	/* assume we are in 1970...2069 */
79	/* detect the polarity heuristically. see note above. */
80	pcf85063->c_polarity = (buf[PCF85063_REG_MO] & PCF85063_MO_C) ?
81		(tm->tm_year >= 100) : (tm->tm_year < 100);
82
83	/* the clock can give out invalid datetime, but we cannot return
84	 * -EINVAL otherwise hwclock will refuse to set the time on bootup.
85	 */
86	if (rtc_valid_tm(tm) < 0)
87		dev_err(&client->dev, "retrieved date/time is not valid.\n");
88
89	return 0;
90}
91
92static int pcf85063_set_datetime(struct i2c_client *client, struct rtc_time *tm)
93{
94	int i = 0, err = 0;
95	unsigned char buf[11];
96
97	/* Control & status */
98	buf[PCF85063_REG_CTRL1] = 0;
99	buf[PCF85063_REG_CTRL2] = 5;
100
101	/* hours, minutes and seconds */
102	buf[PCF85063_REG_SC] = bin2bcd(tm->tm_sec) & 0x7F;
103
104	buf[PCF85063_REG_MN] = bin2bcd(tm->tm_min);
105	buf[PCF85063_REG_HR] = bin2bcd(tm->tm_hour);
106
107	/* Day of month, 1 - 31 */
108	buf[PCF85063_REG_DM] = bin2bcd(tm->tm_mday);
109
110	/* Day, 0 - 6 */
111	buf[PCF85063_REG_DW] = tm->tm_wday & 0x07;
112
113	/* month, 1 - 12 */
114	buf[PCF85063_REG_MO] = bin2bcd(tm->tm_mon + 1);
115
116	/* year and century */
117	buf[PCF85063_REG_YR] = bin2bcd(tm->tm_year % 100);
118
119	/* write register's data */
120	for (i = 0; i < sizeof(buf); i++) {
121		unsigned char data[2] = { i, buf[i] };
122
123		err = i2c_master_send(client, data, sizeof(data));
124		if (err != sizeof(data)) {
125			dev_err(&client->dev, "%s: err=%d addr=%02x, data=%02x\n",
126					__func__, err, data[0], data[1]);
127			return -EIO;
128		}
129	}
130
131	return 0;
132}
133
134static int pcf85063_rtc_read_time(struct device *dev, struct rtc_time *tm)
135{
136	return pcf85063_get_datetime(to_i2c_client(dev), tm);
137}
138
139static int pcf85063_rtc_set_time(struct device *dev, struct rtc_time *tm)
140{
141	return pcf85063_set_datetime(to_i2c_client(dev), tm);
142}
143
144static const struct rtc_class_ops pcf85063_rtc_ops = {
145	.read_time	= pcf85063_rtc_read_time,
146	.set_time	= pcf85063_rtc_set_time
147};
148
149static int pcf85063_probe(struct i2c_client *client,
150				const struct i2c_device_id *id)
151{
152	struct pcf85063 *pcf85063;
153
154	dev_dbg(&client->dev, "%s\n", __func__);
155
156	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
157		return -ENODEV;
158
159	pcf85063 = devm_kzalloc(&client->dev, sizeof(struct pcf85063),
160				GFP_KERNEL);
161	if (!pcf85063)
162		return -ENOMEM;
163
164	dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
165
166	i2c_set_clientdata(client, pcf85063);
167
168	pcf85063->rtc = devm_rtc_device_register(&client->dev,
169				pcf85063_driver.driver.name,
170				&pcf85063_rtc_ops, THIS_MODULE);
171
172	return PTR_ERR_OR_ZERO(pcf85063->rtc);
173}
174
175static const struct i2c_device_id pcf85063_id[] = {
176	{ "pcf85063", 0 },
177	{ }
178};
179MODULE_DEVICE_TABLE(i2c, pcf85063_id);
180
181#ifdef CONFIG_OF
182static const struct of_device_id pcf85063_of_match[] = {
183	{ .compatible = "nxp,pcf85063" },
184	{}
185};
186MODULE_DEVICE_TABLE(of, pcf85063_of_match);
187#endif
188
189static struct i2c_driver pcf85063_driver = {
190	.driver		= {
191		.name	= "rtc-pcf85063",
192		.owner	= THIS_MODULE,
193		.of_match_table = of_match_ptr(pcf85063_of_match),
194	},
195	.probe		= pcf85063_probe,
196	.id_table	= pcf85063_id,
197};
198
199module_i2c_driver(pcf85063_driver);
200
201MODULE_AUTHOR("Søren Andersen <san@rosetechnology.dk>");
202MODULE_DESCRIPTION("PCF85063 RTC driver");
203MODULE_LICENSE("GPL");
204MODULE_VERSION(DRV_VERSION);
205