1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Driver for Epson RTC-9701JE |
4 | * |
5 | * Copyright (C) 2008 Magnus Damm |
6 | * |
7 | * Based on rtc-max6902.c |
8 | * |
9 | * Copyright (C) 2006 8D Technologies inc. |
10 | * Copyright (C) 2004 Compulab Ltd. |
11 | */ |
12 | |
13 | #include <linux/module.h> |
14 | #include <linux/kernel.h> |
15 | #include <linux/platform_device.h> |
16 | #include <linux/device.h> |
17 | #include <linux/init.h> |
18 | #include <linux/rtc.h> |
19 | #include <linux/spi/spi.h> |
20 | #include <linux/bcd.h> |
21 | #include <linux/delay.h> |
22 | #include <linux/bitops.h> |
23 | |
24 | #define RSECCNT 0x00 /* Second Counter */ |
25 | #define RMINCNT 0x01 /* Minute Counter */ |
26 | #define RHRCNT 0x02 /* Hour Counter */ |
27 | #define RWKCNT 0x03 /* Week Counter */ |
28 | #define RDAYCNT 0x04 /* Day Counter */ |
29 | #define RMONCNT 0x05 /* Month Counter */ |
30 | #define RYRCNT 0x06 /* Year Counter */ |
31 | #define R100CNT 0x07 /* Y100 Counter */ |
32 | #define RMINAR 0x08 /* Minute Alarm */ |
33 | #define RHRAR 0x09 /* Hour Alarm */ |
34 | #define RWKAR 0x0a /* Week/Day Alarm */ |
35 | #define RTIMCNT 0x0c /* Interval Timer */ |
36 | #define REXT 0x0d /* Extension Register */ |
37 | #define RFLAG 0x0e /* RTC Flag Register */ |
38 | #define RCR 0x0f /* RTC Control Register */ |
39 | |
40 | static int write_reg(struct device *dev, int address, unsigned char data) |
41 | { |
42 | struct spi_device *spi = to_spi_device(dev); |
43 | unsigned char buf[2]; |
44 | |
45 | buf[0] = address & 0x7f; |
46 | buf[1] = data; |
47 | |
48 | return spi_write(spi, buf, ARRAY_SIZE(buf)); |
49 | } |
50 | |
51 | static int read_regs(struct device *dev, unsigned char *regs, int no_regs) |
52 | { |
53 | struct spi_device *spi = to_spi_device(dev); |
54 | u8 txbuf[1], rxbuf[1]; |
55 | int k, ret; |
56 | |
57 | ret = 0; |
58 | |
59 | for (k = 0; ret == 0 && k < no_regs; k++) { |
60 | txbuf[0] = 0x80 | regs[k]; |
61 | ret = spi_write_then_read(spi, txbuf, n_tx: 1, rxbuf, n_rx: 1); |
62 | regs[k] = rxbuf[0]; |
63 | } |
64 | |
65 | return ret; |
66 | } |
67 | |
68 | static int r9701_get_datetime(struct device *dev, struct rtc_time *dt) |
69 | { |
70 | int ret; |
71 | unsigned char buf[] = { RSECCNT, RMINCNT, RHRCNT, |
72 | RDAYCNT, RMONCNT, RYRCNT }; |
73 | |
74 | ret = read_regs(dev, regs: buf, ARRAY_SIZE(buf)); |
75 | if (ret) |
76 | return ret; |
77 | |
78 | dt->tm_sec = bcd2bin(buf[0]); /* RSECCNT */ |
79 | dt->tm_min = bcd2bin(buf[1]); /* RMINCNT */ |
80 | dt->tm_hour = bcd2bin(buf[2]); /* RHRCNT */ |
81 | |
82 | dt->tm_mday = bcd2bin(buf[3]); /* RDAYCNT */ |
83 | dt->tm_mon = bcd2bin(buf[4]) - 1; /* RMONCNT */ |
84 | dt->tm_year = bcd2bin(buf[5]) + 100; /* RYRCNT */ |
85 | |
86 | return 0; |
87 | } |
88 | |
89 | static int r9701_set_datetime(struct device *dev, struct rtc_time *dt) |
90 | { |
91 | int ret; |
92 | |
93 | ret = write_reg(dev, RHRCNT, bin2bcd(dt->tm_hour)); |
94 | ret = ret ? ret : write_reg(dev, RMINCNT, bin2bcd(dt->tm_min)); |
95 | ret = ret ? ret : write_reg(dev, RSECCNT, bin2bcd(dt->tm_sec)); |
96 | ret = ret ? ret : write_reg(dev, RDAYCNT, bin2bcd(dt->tm_mday)); |
97 | ret = ret ? ret : write_reg(dev, RMONCNT, bin2bcd(dt->tm_mon + 1)); |
98 | ret = ret ? ret : write_reg(dev, RYRCNT, bin2bcd(dt->tm_year - 100)); |
99 | |
100 | return ret; |
101 | } |
102 | |
103 | static const struct rtc_class_ops r9701_rtc_ops = { |
104 | .read_time = r9701_get_datetime, |
105 | .set_time = r9701_set_datetime, |
106 | }; |
107 | |
108 | static int r9701_probe(struct spi_device *spi) |
109 | { |
110 | struct rtc_device *rtc; |
111 | unsigned char tmp; |
112 | int res; |
113 | |
114 | tmp = R100CNT; |
115 | res = read_regs(dev: &spi->dev, regs: &tmp, no_regs: 1); |
116 | if (res || tmp != 0x20) { |
117 | dev_err(&spi->dev, "cannot read RTC register\n" ); |
118 | return -ENODEV; |
119 | } |
120 | |
121 | rtc = devm_rtc_allocate_device(dev: &spi->dev); |
122 | if (IS_ERR(ptr: rtc)) |
123 | return PTR_ERR(ptr: rtc); |
124 | |
125 | spi_set_drvdata(spi, data: rtc); |
126 | rtc->ops = &r9701_rtc_ops; |
127 | rtc->range_min = RTC_TIMESTAMP_BEGIN_2000; |
128 | rtc->range_max = RTC_TIMESTAMP_END_2099; |
129 | |
130 | return devm_rtc_register_device(rtc); |
131 | } |
132 | |
133 | static struct spi_driver r9701_driver = { |
134 | .driver = { |
135 | .name = "rtc-r9701" , |
136 | }, |
137 | .probe = r9701_probe, |
138 | }; |
139 | |
140 | module_spi_driver(r9701_driver); |
141 | |
142 | MODULE_DESCRIPTION("r9701 spi RTC driver" ); |
143 | MODULE_AUTHOR("Magnus Damm <damm@opensource.se>" ); |
144 | MODULE_LICENSE("GPL" ); |
145 | MODULE_ALIAS("spi:rtc-r9701" ); |
146 | |