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Thomas Bogendoerfer537739d2007-07-17 04:05:06 -07001/*
2 * Dallas DS1216 RTC driver
3 *
4 * Copyright (c) 2007 Thomas Bogendoerfer
5 *
6 */
7
8#include <linux/module.h>
9#include <linux/rtc.h>
10#include <linux/platform_device.h>
11#include <linux/bcd.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090012#include <linux/slab.h>
Thomas Bogendoerfer537739d2007-07-17 04:05:06 -070013
Thomas Bogendoerfer537739d2007-07-17 04:05:06 -070014struct ds1216_regs {
15 u8 tsec;
16 u8 sec;
17 u8 min;
18 u8 hour;
19 u8 wday;
20 u8 mday;
21 u8 month;
22 u8 year;
23};
24
25#define DS1216_HOUR_1224 (1 << 7)
26#define DS1216_HOUR_AMPM (1 << 5)
27
28struct ds1216_priv {
29 struct rtc_device *rtc;
30 void __iomem *ioaddr;
Thomas Bogendoerfer537739d2007-07-17 04:05:06 -070031};
32
33static const u8 magic[] = {
34 0xc5, 0x3a, 0xa3, 0x5c, 0xc5, 0x3a, 0xa3, 0x5c
35};
36
37/*
38 * Read the 64 bit we'd like to have - It a series
39 * of 64 bits showing up in the LSB of the base register.
40 *
41 */
42static void ds1216_read(u8 __iomem *ioaddr, u8 *buf)
43{
44 unsigned char c;
45 int i, j;
46
47 for (i = 0; i < 8; i++) {
48 c = 0;
49 for (j = 0; j < 8; j++)
50 c |= (readb(ioaddr) & 0x1) << j;
51 buf[i] = c;
52 }
53}
54
55static void ds1216_write(u8 __iomem *ioaddr, const u8 *buf)
56{
57 unsigned char c;
58 int i, j;
59
60 for (i = 0; i < 8; i++) {
61 c = buf[i];
62 for (j = 0; j < 8; j++) {
63 writeb(c, ioaddr);
64 c = c >> 1;
65 }
66 }
67}
68
69static void ds1216_switch_ds_to_clock(u8 __iomem *ioaddr)
70{
71 /* Reset magic pointer */
72 readb(ioaddr);
73 /* Write 64 bit magic to DS1216 */
74 ds1216_write(ioaddr, magic);
75}
76
77static int ds1216_rtc_read_time(struct device *dev, struct rtc_time *tm)
78{
79 struct platform_device *pdev = to_platform_device(dev);
80 struct ds1216_priv *priv = platform_get_drvdata(pdev);
81 struct ds1216_regs regs;
82
83 ds1216_switch_ds_to_clock(priv->ioaddr);
84 ds1216_read(priv->ioaddr, (u8 *)&regs);
85
Adrian Bunkfe20ba72008-10-18 20:28:41 -070086 tm->tm_sec = bcd2bin(regs.sec);
87 tm->tm_min = bcd2bin(regs.min);
Thomas Bogendoerfer537739d2007-07-17 04:05:06 -070088 if (regs.hour & DS1216_HOUR_1224) {
89 /* AM/PM mode */
Adrian Bunkfe20ba72008-10-18 20:28:41 -070090 tm->tm_hour = bcd2bin(regs.hour & 0x1f);
Thomas Bogendoerfer537739d2007-07-17 04:05:06 -070091 if (regs.hour & DS1216_HOUR_AMPM)
92 tm->tm_hour += 12;
93 } else
Adrian Bunkfe20ba72008-10-18 20:28:41 -070094 tm->tm_hour = bcd2bin(regs.hour & 0x3f);
Thomas Bogendoerfer537739d2007-07-17 04:05:06 -070095 tm->tm_wday = (regs.wday & 7) - 1;
Adrian Bunkfe20ba72008-10-18 20:28:41 -070096 tm->tm_mday = bcd2bin(regs.mday & 0x3f);
97 tm->tm_mon = bcd2bin(regs.month & 0x1f);
98 tm->tm_year = bcd2bin(regs.year);
Thomas Bogendoerfer537739d2007-07-17 04:05:06 -070099 if (tm->tm_year < 70)
100 tm->tm_year += 100;
Alessandro Zummo97a1f952009-01-06 14:42:23 -0800101
102 return rtc_valid_tm(tm);
Thomas Bogendoerfer537739d2007-07-17 04:05:06 -0700103}
104
105static int ds1216_rtc_set_time(struct device *dev, struct rtc_time *tm)
106{
107 struct platform_device *pdev = to_platform_device(dev);
108 struct ds1216_priv *priv = platform_get_drvdata(pdev);
109 struct ds1216_regs regs;
110
111 ds1216_switch_ds_to_clock(priv->ioaddr);
112 ds1216_read(priv->ioaddr, (u8 *)&regs);
113
114 regs.tsec = 0; /* clear 0.1 and 0.01 seconds */
Adrian Bunkfe20ba72008-10-18 20:28:41 -0700115 regs.sec = bin2bcd(tm->tm_sec);
116 regs.min = bin2bcd(tm->tm_min);
Thomas Bogendoerfer537739d2007-07-17 04:05:06 -0700117 regs.hour &= DS1216_HOUR_1224;
118 if (regs.hour && tm->tm_hour > 12) {
119 regs.hour |= DS1216_HOUR_AMPM;
120 tm->tm_hour -= 12;
121 }
Adrian Bunkfe20ba72008-10-18 20:28:41 -0700122 regs.hour |= bin2bcd(tm->tm_hour);
Thomas Bogendoerfer537739d2007-07-17 04:05:06 -0700123 regs.wday &= ~7;
124 regs.wday |= tm->tm_wday;
Adrian Bunkfe20ba72008-10-18 20:28:41 -0700125 regs.mday = bin2bcd(tm->tm_mday);
126 regs.month = bin2bcd(tm->tm_mon);
127 regs.year = bin2bcd(tm->tm_year % 100);
Thomas Bogendoerfer537739d2007-07-17 04:05:06 -0700128
129 ds1216_switch_ds_to_clock(priv->ioaddr);
130 ds1216_write(priv->ioaddr, (u8 *)&regs);
131 return 0;
132}
133
134static const struct rtc_class_ops ds1216_rtc_ops = {
135 .read_time = ds1216_rtc_read_time,
136 .set_time = ds1216_rtc_set_time,
137};
138
Alessandro Zummo97a1f952009-01-06 14:42:23 -0800139static int __init ds1216_rtc_probe(struct platform_device *pdev)
Thomas Bogendoerfer537739d2007-07-17 04:05:06 -0700140{
Thomas Bogendoerfer537739d2007-07-17 04:05:06 -0700141 struct resource *res;
142 struct ds1216_priv *priv;
Thomas Bogendoerfer537739d2007-07-17 04:05:06 -0700143 u8 dummy[8];
144
Jingoo Han15c15672013-04-29 16:20:37 -0700145 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
Thomas Bogendoerfer537739d2007-07-17 04:05:06 -0700146 if (!priv)
147 return -ENOMEM;
Alessandro Zummo97a1f952009-01-06 14:42:23 -0800148
149 platform_set_drvdata(pdev, priv);
150
Julia Lawalle0442532013-08-14 11:11:21 +0200151 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
Jingoo Han15c15672013-04-29 16:20:37 -0700152 priv->ioaddr = devm_ioremap_resource(&pdev->dev, res);
153 if (IS_ERR(priv->ioaddr))
154 return PTR_ERR(priv->ioaddr);
155
156 priv->rtc = devm_rtc_device_register(&pdev->dev, "ds1216",
157 &ds1216_rtc_ops, THIS_MODULE);
158 if (IS_ERR(priv->rtc))
159 return PTR_ERR(priv->rtc);
Thomas Bogendoerfer537739d2007-07-17 04:05:06 -0700160
161 /* dummy read to get clock into a known state */
162 ds1216_read(priv->ioaddr, dummy);
163 return 0;
Thomas Bogendoerfer537739d2007-07-17 04:05:06 -0700164}
165
Thomas Bogendoerfer537739d2007-07-17 04:05:06 -0700166static struct platform_driver ds1216_rtc_platform_driver = {
167 .driver = {
168 .name = "rtc-ds1216",
Thomas Bogendoerfer537739d2007-07-17 04:05:06 -0700169 },
Thomas Bogendoerfer537739d2007-07-17 04:05:06 -0700170};
171
Fabio Porcedda061d2a32013-07-03 15:08:03 -0700172module_platform_driver_probe(ds1216_rtc_platform_driver, ds1216_rtc_probe);
Thomas Bogendoerfer537739d2007-07-17 04:05:06 -0700173
174MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>");
175MODULE_DESCRIPTION("DS1216 RTC driver");
176MODULE_LICENSE("GPL");
Kay Sieversad28a072008-04-10 21:29:25 -0700177MODULE_ALIAS("platform:rtc-ds1216");