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1// SPDX-License-Identifier: GPL-2.0-only
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>
13#include <linux/slab.h>
14
15struct 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
29struct ds1216_priv {
30 struct rtc_device *rtc;
31 void __iomem *ioaddr;
32};
33
34static 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 */
43static 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
56static 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
70static 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
78static int ds1216_rtc_read_time(struct device *dev, struct rtc_time *tm)
79{
80 struct ds1216_priv *priv = dev_get_drvdata(dev);
81 struct ds1216_regs regs;
82
83 ds1216_switch_ds_to_clock(priv->ioaddr);
84 ds1216_read(priv->ioaddr, (u8 *)®s);
85
86 tm->tm_sec = bcd2bin(regs.sec);
87 tm->tm_min = bcd2bin(regs.min);
88 if (regs.hour & DS1216_HOUR_1224) {
89 /* AM/PM mode */
90 tm->tm_hour = bcd2bin(regs.hour & 0x1f);
91 if (regs.hour & DS1216_HOUR_AMPM)
92 tm->tm_hour += 12;
93 } else
94 tm->tm_hour = bcd2bin(regs.hour & 0x3f);
95 tm->tm_wday = (regs.wday & 7) - 1;
96 tm->tm_mday = bcd2bin(regs.mday & 0x3f);
97 tm->tm_mon = bcd2bin(regs.month & 0x1f);
98 tm->tm_year = bcd2bin(regs.year);
99 if (tm->tm_year < 70)
100 tm->tm_year += 100;
101
102 return 0;
103}
104
105static int ds1216_rtc_set_time(struct device *dev, struct rtc_time *tm)
106{
107 struct ds1216_priv *priv = dev_get_drvdata(dev);
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 */
114 regs.sec = bin2bcd(tm->tm_sec);
115 regs.min = bin2bcd(tm->tm_min);
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 }
121 regs.hour |= bin2bcd(tm->tm_hour);
122 regs.wday &= ~7;
123 regs.wday |= tm->tm_wday;
124 regs.mday = bin2bcd(tm->tm_mday);
125 regs.month = bin2bcd(tm->tm_mon);
126 regs.year = bin2bcd(tm->tm_year % 100);
127
128 ds1216_switch_ds_to_clock(priv->ioaddr);
129 ds1216_write(priv->ioaddr, (u8 *)®s);
130 return 0;
131}
132
133static const struct rtc_class_ops ds1216_rtc_ops = {
134 .read_time = ds1216_rtc_read_time,
135 .set_time = ds1216_rtc_set_time,
136};
137
138static int __init ds1216_rtc_probe(struct platform_device *pdev)
139{
140 struct ds1216_priv *priv;
141 u8 dummy[8];
142
143 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
144 if (!priv)
145 return -ENOMEM;
146
147 platform_set_drvdata(pdev, priv);
148
149 priv->ioaddr = devm_platform_ioremap_resource(pdev, 0);
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);
157
158 /* dummy read to get clock into a known state */
159 ds1216_read(priv->ioaddr, dummy);
160 return 0;
161}
162
163static struct platform_driver ds1216_rtc_platform_driver = {
164 .driver = {
165 .name = "rtc-ds1216",
166 },
167};
168
169module_platform_driver_probe(ds1216_rtc_platform_driver, ds1216_rtc_probe);
170
171MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>");
172MODULE_DESCRIPTION("DS1216 RTC driver");
173MODULE_LICENSE("GPL");
174MODULE_ALIAS("platform:rtc-ds1216");
1/*
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>
12#include <linux/slab.h>
13
14#define DRV_VERSION "0.2"
15
16struct ds1216_regs {
17 u8 tsec;
18 u8 sec;
19 u8 min;
20 u8 hour;
21 u8 wday;
22 u8 mday;
23 u8 month;
24 u8 year;
25};
26
27#define DS1216_HOUR_1224 (1 << 7)
28#define DS1216_HOUR_AMPM (1 << 5)
29
30struct ds1216_priv {
31 struct rtc_device *rtc;
32 void __iomem *ioaddr;
33 size_t size;
34 unsigned long baseaddr;
35};
36
37static const u8 magic[] = {
38 0xc5, 0x3a, 0xa3, 0x5c, 0xc5, 0x3a, 0xa3, 0x5c
39};
40
41/*
42 * Read the 64 bit we'd like to have - It a series
43 * of 64 bits showing up in the LSB of the base register.
44 *
45 */
46static void ds1216_read(u8 __iomem *ioaddr, u8 *buf)
47{
48 unsigned char c;
49 int i, j;
50
51 for (i = 0; i < 8; i++) {
52 c = 0;
53 for (j = 0; j < 8; j++)
54 c |= (readb(ioaddr) & 0x1) << j;
55 buf[i] = c;
56 }
57}
58
59static void ds1216_write(u8 __iomem *ioaddr, const u8 *buf)
60{
61 unsigned char c;
62 int i, j;
63
64 for (i = 0; i < 8; i++) {
65 c = buf[i];
66 for (j = 0; j < 8; j++) {
67 writeb(c, ioaddr);
68 c = c >> 1;
69 }
70 }
71}
72
73static void ds1216_switch_ds_to_clock(u8 __iomem *ioaddr)
74{
75 /* Reset magic pointer */
76 readb(ioaddr);
77 /* Write 64 bit magic to DS1216 */
78 ds1216_write(ioaddr, magic);
79}
80
81static int ds1216_rtc_read_time(struct device *dev, struct rtc_time *tm)
82{
83 struct platform_device *pdev = to_platform_device(dev);
84 struct ds1216_priv *priv = platform_get_drvdata(pdev);
85 struct ds1216_regs regs;
86
87 ds1216_switch_ds_to_clock(priv->ioaddr);
88 ds1216_read(priv->ioaddr, (u8 *)®s);
89
90 tm->tm_sec = bcd2bin(regs.sec);
91 tm->tm_min = bcd2bin(regs.min);
92 if (regs.hour & DS1216_HOUR_1224) {
93 /* AM/PM mode */
94 tm->tm_hour = bcd2bin(regs.hour & 0x1f);
95 if (regs.hour & DS1216_HOUR_AMPM)
96 tm->tm_hour += 12;
97 } else
98 tm->tm_hour = bcd2bin(regs.hour & 0x3f);
99 tm->tm_wday = (regs.wday & 7) - 1;
100 tm->tm_mday = bcd2bin(regs.mday & 0x3f);
101 tm->tm_mon = bcd2bin(regs.month & 0x1f);
102 tm->tm_year = bcd2bin(regs.year);
103 if (tm->tm_year < 70)
104 tm->tm_year += 100;
105
106 return rtc_valid_tm(tm);
107}
108
109static int ds1216_rtc_set_time(struct device *dev, struct rtc_time *tm)
110{
111 struct platform_device *pdev = to_platform_device(dev);
112 struct ds1216_priv *priv = platform_get_drvdata(pdev);
113 struct ds1216_regs regs;
114
115 ds1216_switch_ds_to_clock(priv->ioaddr);
116 ds1216_read(priv->ioaddr, (u8 *)®s);
117
118 regs.tsec = 0; /* clear 0.1 and 0.01 seconds */
119 regs.sec = bin2bcd(tm->tm_sec);
120 regs.min = bin2bcd(tm->tm_min);
121 regs.hour &= DS1216_HOUR_1224;
122 if (regs.hour && tm->tm_hour > 12) {
123 regs.hour |= DS1216_HOUR_AMPM;
124 tm->tm_hour -= 12;
125 }
126 regs.hour |= bin2bcd(tm->tm_hour);
127 regs.wday &= ~7;
128 regs.wday |= tm->tm_wday;
129 regs.mday = bin2bcd(tm->tm_mday);
130 regs.month = bin2bcd(tm->tm_mon);
131 regs.year = bin2bcd(tm->tm_year % 100);
132
133 ds1216_switch_ds_to_clock(priv->ioaddr);
134 ds1216_write(priv->ioaddr, (u8 *)®s);
135 return 0;
136}
137
138static const struct rtc_class_ops ds1216_rtc_ops = {
139 .read_time = ds1216_rtc_read_time,
140 .set_time = ds1216_rtc_set_time,
141};
142
143static int __init ds1216_rtc_probe(struct platform_device *pdev)
144{
145 struct resource *res;
146 struct ds1216_priv *priv;
147 int ret = 0;
148 u8 dummy[8];
149
150 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
151 if (!res)
152 return -ENODEV;
153 priv = kzalloc(sizeof *priv, GFP_KERNEL);
154 if (!priv)
155 return -ENOMEM;
156
157 platform_set_drvdata(pdev, priv);
158
159 priv->size = resource_size(res);
160 if (!request_mem_region(res->start, priv->size, pdev->name)) {
161 ret = -EBUSY;
162 goto out;
163 }
164 priv->baseaddr = res->start;
165 priv->ioaddr = ioremap(priv->baseaddr, priv->size);
166 if (!priv->ioaddr) {
167 ret = -ENOMEM;
168 goto out;
169 }
170 priv->rtc = rtc_device_register("ds1216", &pdev->dev,
171 &ds1216_rtc_ops, THIS_MODULE);
172 if (IS_ERR(priv->rtc)) {
173 ret = PTR_ERR(priv->rtc);
174 goto out;
175 }
176
177 /* dummy read to get clock into a known state */
178 ds1216_read(priv->ioaddr, dummy);
179 return 0;
180
181out:
182 if (priv->ioaddr)
183 iounmap(priv->ioaddr);
184 if (priv->baseaddr)
185 release_mem_region(priv->baseaddr, priv->size);
186 kfree(priv);
187 return ret;
188}
189
190static int __exit ds1216_rtc_remove(struct platform_device *pdev)
191{
192 struct ds1216_priv *priv = platform_get_drvdata(pdev);
193
194 rtc_device_unregister(priv->rtc);
195 iounmap(priv->ioaddr);
196 release_mem_region(priv->baseaddr, priv->size);
197 kfree(priv);
198 return 0;
199}
200
201static struct platform_driver ds1216_rtc_platform_driver = {
202 .driver = {
203 .name = "rtc-ds1216",
204 .owner = THIS_MODULE,
205 },
206 .remove = __exit_p(ds1216_rtc_remove),
207};
208
209static int __init ds1216_rtc_init(void)
210{
211 return platform_driver_probe(&ds1216_rtc_platform_driver, ds1216_rtc_probe);
212}
213
214static void __exit ds1216_rtc_exit(void)
215{
216 platform_driver_unregister(&ds1216_rtc_platform_driver);
217}
218
219MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>");
220MODULE_DESCRIPTION("DS1216 RTC driver");
221MODULE_LICENSE("GPL");
222MODULE_VERSION(DRV_VERSION);
223MODULE_ALIAS("platform:rtc-ds1216");
224
225module_init(ds1216_rtc_init);
226module_exit(ds1216_rtc_exit);