Commit | Line | Data |
---|---|---|
d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
8fc2c767 KH |
2 | /* |
3 | * Driver for ST M41T94 SPI RTC | |
4 | * | |
5 | * Copyright (C) 2008 Kim B. Heino | |
8fc2c767 KH |
6 | */ |
7 | ||
8 | #include <linux/module.h> | |
9 | #include <linux/kernel.h> | |
10 | #include <linux/platform_device.h> | |
11 | #include <linux/rtc.h> | |
12 | #include <linux/spi/spi.h> | |
13 | #include <linux/bcd.h> | |
14 | ||
15 | #define M41T94_REG_SECONDS 0x01 | |
16 | #define M41T94_REG_MINUTES 0x02 | |
17 | #define M41T94_REG_HOURS 0x03 | |
18 | #define M41T94_REG_WDAY 0x04 | |
19 | #define M41T94_REG_DAY 0x05 | |
20 | #define M41T94_REG_MONTH 0x06 | |
21 | #define M41T94_REG_YEAR 0x07 | |
22 | #define M41T94_REG_HT 0x0c | |
23 | ||
24 | #define M41T94_BIT_HALT 0x40 | |
25 | #define M41T94_BIT_STOP 0x80 | |
26 | #define M41T94_BIT_CB 0x40 | |
27 | #define M41T94_BIT_CEB 0x80 | |
28 | ||
29 | static int m41t94_set_time(struct device *dev, struct rtc_time *tm) | |
30 | { | |
31 | struct spi_device *spi = to_spi_device(dev); | |
32 | u8 buf[8]; /* write cmd + 7 registers */ | |
33 | ||
34 | dev_dbg(dev, "%s secs=%d, mins=%d, " | |
35 | "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n", | |
36 | "write", tm->tm_sec, tm->tm_min, | |
37 | tm->tm_hour, tm->tm_mday, | |
38 | tm->tm_mon, tm->tm_year, tm->tm_wday); | |
39 | ||
40 | buf[0] = 0x80 | M41T94_REG_SECONDS; /* write time + date */ | |
fe20ba70 AB |
41 | buf[M41T94_REG_SECONDS] = bin2bcd(tm->tm_sec); |
42 | buf[M41T94_REG_MINUTES] = bin2bcd(tm->tm_min); | |
43 | buf[M41T94_REG_HOURS] = bin2bcd(tm->tm_hour); | |
44 | buf[M41T94_REG_WDAY] = bin2bcd(tm->tm_wday + 1); | |
45 | buf[M41T94_REG_DAY] = bin2bcd(tm->tm_mday); | |
46 | buf[M41T94_REG_MONTH] = bin2bcd(tm->tm_mon + 1); | |
8fc2c767 KH |
47 | |
48 | buf[M41T94_REG_HOURS] |= M41T94_BIT_CEB; | |
49 | if (tm->tm_year >= 100) | |
50 | buf[M41T94_REG_HOURS] |= M41T94_BIT_CB; | |
fe20ba70 | 51 | buf[M41T94_REG_YEAR] = bin2bcd(tm->tm_year % 100); |
8fc2c767 KH |
52 | |
53 | return spi_write(spi, buf, 8); | |
54 | } | |
55 | ||
56 | static int m41t94_read_time(struct device *dev, struct rtc_time *tm) | |
57 | { | |
58 | struct spi_device *spi = to_spi_device(dev); | |
59 | u8 buf[2]; | |
60 | int ret, hour; | |
61 | ||
62 | /* clear halt update bit */ | |
63 | ret = spi_w8r8(spi, M41T94_REG_HT); | |
64 | if (ret < 0) | |
65 | return ret; | |
66 | if (ret & M41T94_BIT_HALT) { | |
67 | buf[0] = 0x80 | M41T94_REG_HT; | |
68 | buf[1] = ret & ~M41T94_BIT_HALT; | |
69 | spi_write(spi, buf, 2); | |
70 | } | |
71 | ||
72 | /* clear stop bit */ | |
73 | ret = spi_w8r8(spi, M41T94_REG_SECONDS); | |
74 | if (ret < 0) | |
75 | return ret; | |
76 | if (ret & M41T94_BIT_STOP) { | |
77 | buf[0] = 0x80 | M41T94_REG_SECONDS; | |
78 | buf[1] = ret & ~M41T94_BIT_STOP; | |
79 | spi_write(spi, buf, 2); | |
80 | } | |
81 | ||
fe20ba70 AB |
82 | tm->tm_sec = bcd2bin(spi_w8r8(spi, M41T94_REG_SECONDS)); |
83 | tm->tm_min = bcd2bin(spi_w8r8(spi, M41T94_REG_MINUTES)); | |
8fc2c767 | 84 | hour = spi_w8r8(spi, M41T94_REG_HOURS); |
fe20ba70 AB |
85 | tm->tm_hour = bcd2bin(hour & 0x3f); |
86 | tm->tm_wday = bcd2bin(spi_w8r8(spi, M41T94_REG_WDAY)) - 1; | |
87 | tm->tm_mday = bcd2bin(spi_w8r8(spi, M41T94_REG_DAY)); | |
88 | tm->tm_mon = bcd2bin(spi_w8r8(spi, M41T94_REG_MONTH)) - 1; | |
89 | tm->tm_year = bcd2bin(spi_w8r8(spi, M41T94_REG_YEAR)); | |
8fc2c767 KH |
90 | if ((hour & M41T94_BIT_CB) || !(hour & M41T94_BIT_CEB)) |
91 | tm->tm_year += 100; | |
92 | ||
93 | dev_dbg(dev, "%s secs=%d, mins=%d, " | |
94 | "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n", | |
95 | "read", tm->tm_sec, tm->tm_min, | |
96 | tm->tm_hour, tm->tm_mday, | |
97 | tm->tm_mon, tm->tm_year, tm->tm_wday); | |
98 | ||
22652ba7 | 99 | return 0; |
8fc2c767 KH |
100 | } |
101 | ||
102 | static const struct rtc_class_ops m41t94_rtc_ops = { | |
103 | .read_time = m41t94_read_time, | |
104 | .set_time = m41t94_set_time, | |
105 | }; | |
106 | ||
107 | static struct spi_driver m41t94_driver; | |
108 | ||
5a167f45 | 109 | static int m41t94_probe(struct spi_device *spi) |
8fc2c767 KH |
110 | { |
111 | struct rtc_device *rtc; | |
112 | int res; | |
113 | ||
114 | spi->bits_per_word = 8; | |
115 | spi_setup(spi); | |
116 | ||
117 | res = spi_w8r8(spi, M41T94_REG_SECONDS); | |
118 | if (res < 0) { | |
119 | dev_err(&spi->dev, "not found.\n"); | |
120 | return res; | |
121 | } | |
122 | ||
fb320d0a JH |
123 | rtc = devm_rtc_device_register(&spi->dev, m41t94_driver.driver.name, |
124 | &m41t94_rtc_ops, THIS_MODULE); | |
8fc2c767 KH |
125 | if (IS_ERR(rtc)) |
126 | return PTR_ERR(rtc); | |
127 | ||
ee62474d | 128 | spi_set_drvdata(spi, rtc); |
8fc2c767 KH |
129 | |
130 | return 0; | |
131 | } | |
132 | ||
8fc2c767 KH |
133 | static struct spi_driver m41t94_driver = { |
134 | .driver = { | |
135 | .name = "rtc-m41t94", | |
8fc2c767 KH |
136 | }, |
137 | .probe = m41t94_probe, | |
8fc2c767 KH |
138 | }; |
139 | ||
109e9418 | 140 | module_spi_driver(m41t94_driver); |
8fc2c767 KH |
141 | |
142 | MODULE_AUTHOR("Kim B. Heino <Kim.Heino@bluegiga.com>"); | |
143 | MODULE_DESCRIPTION("Driver for ST M41T94 SPI RTC"); | |
144 | MODULE_LICENSE("GPL"); | |
e0626e38 | 145 | MODULE_ALIAS("spi:rtc-m41t94"); |