Loading...
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * An rtc driver for the Dallas DS1742
4 *
5 * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
6 *
7 * Copyright (C) 2006 Torsten Ertbjerg Rasmussen <tr@newtec.dk>
8 * - nvram size determined from resource
9 * - this ds1742 driver now supports ds1743.
10 */
11
12#include <linux/bcd.h>
13#include <linux/kernel.h>
14#include <linux/gfp.h>
15#include <linux/delay.h>
16#include <linux/jiffies.h>
17#include <linux/rtc.h>
18#include <linux/of.h>
19#include <linux/platform_device.h>
20#include <linux/io.h>
21#include <linux/module.h>
22
23#define RTC_SIZE 8
24
25#define RTC_CONTROL 0
26#define RTC_CENTURY 0
27#define RTC_SECONDS 1
28#define RTC_MINUTES 2
29#define RTC_HOURS 3
30#define RTC_DAY 4
31#define RTC_DATE 5
32#define RTC_MONTH 6
33#define RTC_YEAR 7
34
35#define RTC_CENTURY_MASK 0x3f
36#define RTC_SECONDS_MASK 0x7f
37#define RTC_DAY_MASK 0x07
38
39/* Bits in the Control/Century register */
40#define RTC_WRITE 0x80
41#define RTC_READ 0x40
42
43/* Bits in the Seconds register */
44#define RTC_STOP 0x80
45
46/* Bits in the Day register */
47#define RTC_BATT_FLAG 0x80
48
49struct rtc_plat_data {
50 void __iomem *ioaddr_nvram;
51 void __iomem *ioaddr_rtc;
52 unsigned long last_jiffies;
53};
54
55static int ds1742_rtc_set_time(struct device *dev, struct rtc_time *tm)
56{
57 struct rtc_plat_data *pdata = dev_get_drvdata(dev);
58 void __iomem *ioaddr = pdata->ioaddr_rtc;
59 u8 century;
60
61 century = bin2bcd((tm->tm_year + 1900) / 100);
62
63 writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
64
65 writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR);
66 writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH);
67 writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY);
68 writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE);
69 writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS);
70 writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES);
71 writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS);
72
73 /* RTC_CENTURY and RTC_CONTROL share same register */
74 writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY);
75 writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
76 return 0;
77}
78
79static int ds1742_rtc_read_time(struct device *dev, struct rtc_time *tm)
80{
81 struct rtc_plat_data *pdata = dev_get_drvdata(dev);
82 void __iomem *ioaddr = pdata->ioaddr_rtc;
83 unsigned int year, month, day, hour, minute, second, week;
84 unsigned int century;
85
86 /* give enough time to update RTC in case of continuous read */
87 if (pdata->last_jiffies == jiffies)
88 msleep(1);
89 pdata->last_jiffies = jiffies;
90 writeb(RTC_READ, ioaddr + RTC_CONTROL);
91 second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;
92 minute = readb(ioaddr + RTC_MINUTES);
93 hour = readb(ioaddr + RTC_HOURS);
94 day = readb(ioaddr + RTC_DATE);
95 week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;
96 month = readb(ioaddr + RTC_MONTH);
97 year = readb(ioaddr + RTC_YEAR);
98 century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
99 writeb(0, ioaddr + RTC_CONTROL);
100 tm->tm_sec = bcd2bin(second);
101 tm->tm_min = bcd2bin(minute);
102 tm->tm_hour = bcd2bin(hour);
103 tm->tm_mday = bcd2bin(day);
104 tm->tm_wday = bcd2bin(week);
105 tm->tm_mon = bcd2bin(month) - 1;
106 /* year is 1900 + tm->tm_year */
107 tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900;
108
109 return 0;
110}
111
112static const struct rtc_class_ops ds1742_rtc_ops = {
113 .read_time = ds1742_rtc_read_time,
114 .set_time = ds1742_rtc_set_time,
115};
116
117static int ds1742_nvram_read(void *priv, unsigned int pos, void *val,
118 size_t bytes)
119{
120 struct rtc_plat_data *pdata = priv;
121 void __iomem *ioaddr = pdata->ioaddr_nvram;
122 u8 *buf = val;
123
124 for (; bytes; bytes--)
125 *buf++ = readb(ioaddr + pos++);
126 return 0;
127}
128
129static int ds1742_nvram_write(void *priv, unsigned int pos, void *val,
130 size_t bytes)
131{
132 struct rtc_plat_data *pdata = priv;
133 void __iomem *ioaddr = pdata->ioaddr_nvram;
134 u8 *buf = val;
135
136 for (; bytes; bytes--)
137 writeb(*buf++, ioaddr + pos++);
138 return 0;
139}
140
141static int ds1742_rtc_probe(struct platform_device *pdev)
142{
143 struct rtc_device *rtc;
144 struct resource *res;
145 unsigned int cen, sec;
146 struct rtc_plat_data *pdata;
147 void __iomem *ioaddr;
148 int ret = 0;
149 struct nvmem_config nvmem_cfg = {
150 .name = "ds1742_nvram",
151 .reg_read = ds1742_nvram_read,
152 .reg_write = ds1742_nvram_write,
153 };
154
155
156 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
157 if (!pdata)
158 return -ENOMEM;
159
160 ioaddr = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
161 if (IS_ERR(ioaddr))
162 return PTR_ERR(ioaddr);
163
164 pdata->ioaddr_nvram = ioaddr;
165 pdata->ioaddr_rtc = ioaddr + resource_size(res) - RTC_SIZE;
166
167 nvmem_cfg.size = resource_size(res) - RTC_SIZE;
168 nvmem_cfg.priv = pdata;
169
170 /* turn RTC on if it was not on */
171 ioaddr = pdata->ioaddr_rtc;
172 sec = readb(ioaddr + RTC_SECONDS);
173 if (sec & RTC_STOP) {
174 sec &= RTC_SECONDS_MASK;
175 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
176 writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
177 writeb(sec, ioaddr + RTC_SECONDS);
178 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
179 }
180 if (!(readb(ioaddr + RTC_DAY) & RTC_BATT_FLAG))
181 dev_warn(&pdev->dev, "voltage-low detected.\n");
182
183 pdata->last_jiffies = jiffies;
184 platform_set_drvdata(pdev, pdata);
185
186 rtc = devm_rtc_allocate_device(&pdev->dev);
187 if (IS_ERR(rtc))
188 return PTR_ERR(rtc);
189
190 rtc->ops = &ds1742_rtc_ops;
191
192 ret = devm_rtc_register_device(rtc);
193 if (ret)
194 return ret;
195
196 devm_rtc_nvmem_register(rtc, &nvmem_cfg);
197
198 return 0;
199}
200
201static const struct of_device_id __maybe_unused ds1742_rtc_of_match[] = {
202 { .compatible = "maxim,ds1742", },
203 { }
204};
205MODULE_DEVICE_TABLE(of, ds1742_rtc_of_match);
206
207static struct platform_driver ds1742_rtc_driver = {
208 .probe = ds1742_rtc_probe,
209 .driver = {
210 .name = "rtc-ds1742",
211 .of_match_table = of_match_ptr(ds1742_rtc_of_match),
212 },
213};
214
215module_platform_driver(ds1742_rtc_driver);
216
217MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
218MODULE_DESCRIPTION("Dallas DS1742 RTC driver");
219MODULE_LICENSE("GPL");
220MODULE_ALIAS("platform:rtc-ds1742");
1/*
2 * An rtc driver for the Dallas DS1742
3 *
4 * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * Copyright (C) 2006 Torsten Ertbjerg Rasmussen <tr@newtec.dk>
11 * - nvram size determined from resource
12 * - this ds1742 driver now supports ds1743.
13 */
14
15#include <linux/bcd.h>
16#include <linux/kernel.h>
17#include <linux/gfp.h>
18#include <linux/delay.h>
19#include <linux/jiffies.h>
20#include <linux/rtc.h>
21#include <linux/of.h>
22#include <linux/of_device.h>
23#include <linux/platform_device.h>
24#include <linux/io.h>
25#include <linux/module.h>
26
27#define RTC_SIZE 8
28
29#define RTC_CONTROL 0
30#define RTC_CENTURY 0
31#define RTC_SECONDS 1
32#define RTC_MINUTES 2
33#define RTC_HOURS 3
34#define RTC_DAY 4
35#define RTC_DATE 5
36#define RTC_MONTH 6
37#define RTC_YEAR 7
38
39#define RTC_CENTURY_MASK 0x3f
40#define RTC_SECONDS_MASK 0x7f
41#define RTC_DAY_MASK 0x07
42
43/* Bits in the Control/Century register */
44#define RTC_WRITE 0x80
45#define RTC_READ 0x40
46
47/* Bits in the Seconds register */
48#define RTC_STOP 0x80
49
50/* Bits in the Day register */
51#define RTC_BATT_FLAG 0x80
52
53struct rtc_plat_data {
54 void __iomem *ioaddr_nvram;
55 void __iomem *ioaddr_rtc;
56 unsigned long last_jiffies;
57};
58
59static int ds1742_rtc_set_time(struct device *dev, struct rtc_time *tm)
60{
61 struct platform_device *pdev = to_platform_device(dev);
62 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
63 void __iomem *ioaddr = pdata->ioaddr_rtc;
64 u8 century;
65
66 century = bin2bcd((tm->tm_year + 1900) / 100);
67
68 writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
69
70 writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR);
71 writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH);
72 writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY);
73 writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE);
74 writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS);
75 writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES);
76 writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS);
77
78 /* RTC_CENTURY and RTC_CONTROL share same register */
79 writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY);
80 writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
81 return 0;
82}
83
84static int ds1742_rtc_read_time(struct device *dev, struct rtc_time *tm)
85{
86 struct platform_device *pdev = to_platform_device(dev);
87 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
88 void __iomem *ioaddr = pdata->ioaddr_rtc;
89 unsigned int year, month, day, hour, minute, second, week;
90 unsigned int century;
91
92 /* give enough time to update RTC in case of continuous read */
93 if (pdata->last_jiffies == jiffies)
94 msleep(1);
95 pdata->last_jiffies = jiffies;
96 writeb(RTC_READ, ioaddr + RTC_CONTROL);
97 second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;
98 minute = readb(ioaddr + RTC_MINUTES);
99 hour = readb(ioaddr + RTC_HOURS);
100 day = readb(ioaddr + RTC_DATE);
101 week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;
102 month = readb(ioaddr + RTC_MONTH);
103 year = readb(ioaddr + RTC_YEAR);
104 century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
105 writeb(0, ioaddr + RTC_CONTROL);
106 tm->tm_sec = bcd2bin(second);
107 tm->tm_min = bcd2bin(minute);
108 tm->tm_hour = bcd2bin(hour);
109 tm->tm_mday = bcd2bin(day);
110 tm->tm_wday = bcd2bin(week);
111 tm->tm_mon = bcd2bin(month) - 1;
112 /* year is 1900 + tm->tm_year */
113 tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900;
114
115 return 0;
116}
117
118static const struct rtc_class_ops ds1742_rtc_ops = {
119 .read_time = ds1742_rtc_read_time,
120 .set_time = ds1742_rtc_set_time,
121};
122
123static int ds1742_nvram_read(void *priv, unsigned int pos, void *val,
124 size_t bytes)
125{
126 struct rtc_plat_data *pdata = priv;
127 void __iomem *ioaddr = pdata->ioaddr_nvram;
128 u8 *buf = val;
129
130 for (; bytes; bytes--)
131 *buf++ = readb(ioaddr + pos++);
132 return 0;
133}
134
135static int ds1742_nvram_write(void *priv, unsigned int pos, void *val,
136 size_t bytes)
137{
138 struct rtc_plat_data *pdata = priv;
139 void __iomem *ioaddr = pdata->ioaddr_nvram;
140 u8 *buf = val;
141
142 for (; bytes; bytes--)
143 writeb(*buf++, ioaddr + pos++);
144 return 0;
145}
146
147static int ds1742_rtc_probe(struct platform_device *pdev)
148{
149 struct rtc_device *rtc;
150 struct resource *res;
151 unsigned int cen, sec;
152 struct rtc_plat_data *pdata;
153 void __iomem *ioaddr;
154 int ret = 0;
155 struct nvmem_config nvmem_cfg = {
156 .name = "ds1742_nvram",
157 .word_size = 1,
158 .stride = 1,
159 .reg_read = ds1742_nvram_read,
160 .reg_write = ds1742_nvram_write,
161 };
162
163
164 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
165 if (!pdata)
166 return -ENOMEM;
167
168 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
169 ioaddr = devm_ioremap_resource(&pdev->dev, res);
170 if (IS_ERR(ioaddr))
171 return PTR_ERR(ioaddr);
172
173 pdata->ioaddr_nvram = ioaddr;
174 pdata->ioaddr_rtc = ioaddr + resource_size(res) - RTC_SIZE;
175
176 nvmem_cfg.size = resource_size(res) - RTC_SIZE;
177 nvmem_cfg.priv = pdata;
178
179 /* turn RTC on if it was not on */
180 ioaddr = pdata->ioaddr_rtc;
181 sec = readb(ioaddr + RTC_SECONDS);
182 if (sec & RTC_STOP) {
183 sec &= RTC_SECONDS_MASK;
184 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
185 writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
186 writeb(sec, ioaddr + RTC_SECONDS);
187 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
188 }
189 if (!(readb(ioaddr + RTC_DAY) & RTC_BATT_FLAG))
190 dev_warn(&pdev->dev, "voltage-low detected.\n");
191
192 pdata->last_jiffies = jiffies;
193 platform_set_drvdata(pdev, pdata);
194
195 rtc = devm_rtc_allocate_device(&pdev->dev);
196 if (IS_ERR(rtc))
197 return PTR_ERR(rtc);
198
199 rtc->ops = &ds1742_rtc_ops;
200 rtc->nvram_old_abi = true;
201
202 ret = rtc_register_device(rtc);
203 if (ret)
204 return ret;
205
206 if (rtc_nvmem_register(rtc, &nvmem_cfg))
207 dev_err(&pdev->dev, "Unable to register nvmem\n");
208
209 return 0;
210}
211
212static const struct of_device_id __maybe_unused ds1742_rtc_of_match[] = {
213 { .compatible = "maxim,ds1742", },
214 { }
215};
216MODULE_DEVICE_TABLE(of, ds1742_rtc_of_match);
217
218static struct platform_driver ds1742_rtc_driver = {
219 .probe = ds1742_rtc_probe,
220 .driver = {
221 .name = "rtc-ds1742",
222 .of_match_table = of_match_ptr(ds1742_rtc_of_match),
223 },
224};
225
226module_platform_driver(ds1742_rtc_driver);
227
228MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
229MODULE_DESCRIPTION("Dallas DS1742 RTC driver");
230MODULE_LICENSE("GPL");
231MODULE_ALIAS("platform:rtc-ds1742");