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09c434b8 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
537739de TB |
2 | /* |
3 | * Dallas DS1216 RTC driver | |
4 | * | |
5 | * Copyright (c) 2007 Thomas Bogendoerfer | |
6 | * | |
7 | */ | |
8 | ||
9 | #include <linux/module.h> | |
10 | #include <linux/rtc.h> | |
11 | #include <linux/platform_device.h> | |
12 | #include <linux/bcd.h> | |
5a0e3ad6 | 13 | #include <linux/slab.h> |
537739de | 14 | |
537739de TB |
15 | struct ds1216_regs { |
16 | u8 tsec; | |
17 | u8 sec; | |
18 | u8 min; | |
19 | u8 hour; | |
20 | u8 wday; | |
21 | u8 mday; | |
22 | u8 month; | |
23 | u8 year; | |
24 | }; | |
25 | ||
26 | #define DS1216_HOUR_1224 (1 << 7) | |
27 | #define DS1216_HOUR_AMPM (1 << 5) | |
28 | ||
29 | struct ds1216_priv { | |
30 | struct rtc_device *rtc; | |
31 | void __iomem *ioaddr; | |
537739de TB |
32 | }; |
33 | ||
34 | static const u8 magic[] = { | |
35 | 0xc5, 0x3a, 0xa3, 0x5c, 0xc5, 0x3a, 0xa3, 0x5c | |
36 | }; | |
37 | ||
38 | /* | |
39 | * Read the 64 bit we'd like to have - It a series | |
40 | * of 64 bits showing up in the LSB of the base register. | |
41 | * | |
42 | */ | |
43 | static void ds1216_read(u8 __iomem *ioaddr, u8 *buf) | |
44 | { | |
45 | unsigned char c; | |
46 | int i, j; | |
47 | ||
48 | for (i = 0; i < 8; i++) { | |
49 | c = 0; | |
50 | for (j = 0; j < 8; j++) | |
51 | c |= (readb(ioaddr) & 0x1) << j; | |
52 | buf[i] = c; | |
53 | } | |
54 | } | |
55 | ||
56 | static void ds1216_write(u8 __iomem *ioaddr, const u8 *buf) | |
57 | { | |
58 | unsigned char c; | |
59 | int i, j; | |
60 | ||
61 | for (i = 0; i < 8; i++) { | |
62 | c = buf[i]; | |
63 | for (j = 0; j < 8; j++) { | |
64 | writeb(c, ioaddr); | |
65 | c = c >> 1; | |
66 | } | |
67 | } | |
68 | } | |
69 | ||
70 | static void ds1216_switch_ds_to_clock(u8 __iomem *ioaddr) | |
71 | { | |
72 | /* Reset magic pointer */ | |
73 | readb(ioaddr); | |
74 | /* Write 64 bit magic to DS1216 */ | |
75 | ds1216_write(ioaddr, magic); | |
76 | } | |
77 | ||
78 | static int ds1216_rtc_read_time(struct device *dev, struct rtc_time *tm) | |
79 | { | |
85368bb9 | 80 | struct ds1216_priv *priv = dev_get_drvdata(dev); |
537739de TB |
81 | struct ds1216_regs regs; |
82 | ||
83 | ds1216_switch_ds_to_clock(priv->ioaddr); | |
84 | ds1216_read(priv->ioaddr, (u8 *)®s); | |
85 | ||
fe20ba70 AB |
86 | tm->tm_sec = bcd2bin(regs.sec); |
87 | tm->tm_min = bcd2bin(regs.min); | |
537739de TB |
88 | if (regs.hour & DS1216_HOUR_1224) { |
89 | /* AM/PM mode */ | |
fe20ba70 | 90 | tm->tm_hour = bcd2bin(regs.hour & 0x1f); |
537739de TB |
91 | if (regs.hour & DS1216_HOUR_AMPM) |
92 | tm->tm_hour += 12; | |
93 | } else | |
fe20ba70 | 94 | tm->tm_hour = bcd2bin(regs.hour & 0x3f); |
537739de | 95 | tm->tm_wday = (regs.wday & 7) - 1; |
fe20ba70 AB |
96 | tm->tm_mday = bcd2bin(regs.mday & 0x3f); |
97 | tm->tm_mon = bcd2bin(regs.month & 0x1f); | |
98 | tm->tm_year = bcd2bin(regs.year); | |
537739de TB |
99 | if (tm->tm_year < 70) |
100 | tm->tm_year += 100; | |
97a1f953 | 101 | |
22652ba7 | 102 | return 0; |
537739de TB |
103 | } |
104 | ||
105 | static int ds1216_rtc_set_time(struct device *dev, struct rtc_time *tm) | |
106 | { | |
85368bb9 | 107 | struct ds1216_priv *priv = dev_get_drvdata(dev); |
537739de TB |
108 | struct ds1216_regs regs; |
109 | ||
110 | ds1216_switch_ds_to_clock(priv->ioaddr); | |
111 | ds1216_read(priv->ioaddr, (u8 *)®s); | |
112 | ||
113 | regs.tsec = 0; /* clear 0.1 and 0.01 seconds */ | |
fe20ba70 AB |
114 | regs.sec = bin2bcd(tm->tm_sec); |
115 | regs.min = bin2bcd(tm->tm_min); | |
537739de TB |
116 | regs.hour &= DS1216_HOUR_1224; |
117 | if (regs.hour && tm->tm_hour > 12) { | |
118 | regs.hour |= DS1216_HOUR_AMPM; | |
119 | tm->tm_hour -= 12; | |
120 | } | |
fe20ba70 | 121 | regs.hour |= bin2bcd(tm->tm_hour); |
537739de TB |
122 | regs.wday &= ~7; |
123 | regs.wday |= tm->tm_wday; | |
fe20ba70 AB |
124 | regs.mday = bin2bcd(tm->tm_mday); |
125 | regs.month = bin2bcd(tm->tm_mon); | |
126 | regs.year = bin2bcd(tm->tm_year % 100); | |
537739de TB |
127 | |
128 | ds1216_switch_ds_to_clock(priv->ioaddr); | |
129 | ds1216_write(priv->ioaddr, (u8 *)®s); | |
130 | return 0; | |
131 | } | |
132 | ||
133 | static const struct rtc_class_ops ds1216_rtc_ops = { | |
134 | .read_time = ds1216_rtc_read_time, | |
135 | .set_time = ds1216_rtc_set_time, | |
136 | }; | |
137 | ||
97a1f953 | 138 | static int __init ds1216_rtc_probe(struct platform_device *pdev) |
537739de | 139 | { |
537739de | 140 | struct ds1216_priv *priv; |
537739de TB |
141 | u8 dummy[8]; |
142 | ||
15c1567a | 143 | priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); |
537739de TB |
144 | if (!priv) |
145 | return -ENOMEM; | |
97a1f953 AZ |
146 | |
147 | platform_set_drvdata(pdev, priv); | |
148 | ||
09ef18bc | 149 | priv->ioaddr = devm_platform_ioremap_resource(pdev, 0); |
15c1567a JH |
150 | if (IS_ERR(priv->ioaddr)) |
151 | return PTR_ERR(priv->ioaddr); | |
152 | ||
153 | priv->rtc = devm_rtc_device_register(&pdev->dev, "ds1216", | |
154 | &ds1216_rtc_ops, THIS_MODULE); | |
155 | if (IS_ERR(priv->rtc)) | |
156 | return PTR_ERR(priv->rtc); | |
537739de TB |
157 | |
158 | /* dummy read to get clock into a known state */ | |
159 | ds1216_read(priv->ioaddr, dummy); | |
160 | return 0; | |
537739de TB |
161 | } |
162 | ||
537739de TB |
163 | static struct platform_driver ds1216_rtc_platform_driver = { |
164 | .driver = { | |
165 | .name = "rtc-ds1216", | |
537739de | 166 | }, |
537739de TB |
167 | }; |
168 | ||
061d2a3e | 169 | module_platform_driver_probe(ds1216_rtc_platform_driver, ds1216_rtc_probe); |
537739de TB |
170 | |
171 | MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>"); | |
172 | MODULE_DESCRIPTION("DS1216 RTC driver"); | |
173 | MODULE_LICENSE("GPL"); | |
ad28a07b | 174 | MODULE_ALIAS("platform:rtc-ds1216"); |