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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 DRV_VERSION "0.4"
28
29#define RTC_SIZE 8
30
31#define RTC_CONTROL 0
32#define RTC_CENTURY 0
33#define RTC_SECONDS 1
34#define RTC_MINUTES 2
35#define RTC_HOURS 3
36#define RTC_DAY 4
37#define RTC_DATE 5
38#define RTC_MONTH 6
39#define RTC_YEAR 7
40
41#define RTC_CENTURY_MASK 0x3f
42#define RTC_SECONDS_MASK 0x7f
43#define RTC_DAY_MASK 0x07
44
45/* Bits in the Control/Century register */
46#define RTC_WRITE 0x80
47#define RTC_READ 0x40
48
49/* Bits in the Seconds register */
50#define RTC_STOP 0x80
51
52/* Bits in the Day register */
53#define RTC_BATT_FLAG 0x80
54
55struct rtc_plat_data {
56 void __iomem *ioaddr_nvram;
57 void __iomem *ioaddr_rtc;
58 size_t size_nvram;
59 unsigned long last_jiffies;
60 struct bin_attribute nvram_attr;
61};
62
63static int ds1742_rtc_set_time(struct device *dev, struct rtc_time *tm)
64{
65 struct platform_device *pdev = to_platform_device(dev);
66 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
67 void __iomem *ioaddr = pdata->ioaddr_rtc;
68 u8 century;
69
70 century = bin2bcd((tm->tm_year + 1900) / 100);
71
72 writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
73
74 writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR);
75 writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH);
76 writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY);
77 writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE);
78 writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS);
79 writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES);
80 writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS);
81
82 /* RTC_CENTURY and RTC_CONTROL share same register */
83 writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY);
84 writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
85 return 0;
86}
87
88static int ds1742_rtc_read_time(struct device *dev, struct rtc_time *tm)
89{
90 struct platform_device *pdev = to_platform_device(dev);
91 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
92 void __iomem *ioaddr = pdata->ioaddr_rtc;
93 unsigned int year, month, day, hour, minute, second, week;
94 unsigned int century;
95
96 /* give enough time to update RTC in case of continuous read */
97 if (pdata->last_jiffies == jiffies)
98 msleep(1);
99 pdata->last_jiffies = jiffies;
100 writeb(RTC_READ, ioaddr + RTC_CONTROL);
101 second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;
102 minute = readb(ioaddr + RTC_MINUTES);
103 hour = readb(ioaddr + RTC_HOURS);
104 day = readb(ioaddr + RTC_DATE);
105 week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;
106 month = readb(ioaddr + RTC_MONTH);
107 year = readb(ioaddr + RTC_YEAR);
108 century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
109 writeb(0, ioaddr + RTC_CONTROL);
110 tm->tm_sec = bcd2bin(second);
111 tm->tm_min = bcd2bin(minute);
112 tm->tm_hour = bcd2bin(hour);
113 tm->tm_mday = bcd2bin(day);
114 tm->tm_wday = bcd2bin(week);
115 tm->tm_mon = bcd2bin(month) - 1;
116 /* year is 1900 + tm->tm_year */
117 tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900;
118
119 return rtc_valid_tm(tm);
120}
121
122static const struct rtc_class_ops ds1742_rtc_ops = {
123 .read_time = ds1742_rtc_read_time,
124 .set_time = ds1742_rtc_set_time,
125};
126
127static ssize_t ds1742_nvram_read(struct file *filp, struct kobject *kobj,
128 struct bin_attribute *bin_attr,
129 char *buf, loff_t pos, size_t size)
130{
131 struct device *dev = container_of(kobj, struct device, kobj);
132 struct platform_device *pdev = to_platform_device(dev);
133 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
134 void __iomem *ioaddr = pdata->ioaddr_nvram;
135 ssize_t count;
136
137 for (count = 0; count < size; count++)
138 *buf++ = readb(ioaddr + pos++);
139 return count;
140}
141
142static ssize_t ds1742_nvram_write(struct file *filp, struct kobject *kobj,
143 struct bin_attribute *bin_attr,
144 char *buf, loff_t pos, size_t size)
145{
146 struct device *dev = container_of(kobj, struct device, kobj);
147 struct platform_device *pdev = to_platform_device(dev);
148 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
149 void __iomem *ioaddr = pdata->ioaddr_nvram;
150 ssize_t count;
151
152 for (count = 0; count < size; count++)
153 writeb(*buf++, ioaddr + pos++);
154 return count;
155}
156
157static int ds1742_rtc_probe(struct platform_device *pdev)
158{
159 struct rtc_device *rtc;
160 struct resource *res;
161 unsigned int cen, sec;
162 struct rtc_plat_data *pdata;
163 void __iomem *ioaddr;
164 int ret = 0;
165
166 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
167 if (!pdata)
168 return -ENOMEM;
169
170 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
171 ioaddr = devm_ioremap_resource(&pdev->dev, res);
172 if (IS_ERR(ioaddr))
173 return PTR_ERR(ioaddr);
174
175 pdata->ioaddr_nvram = ioaddr;
176 pdata->size_nvram = resource_size(res) - RTC_SIZE;
177 pdata->ioaddr_rtc = ioaddr + pdata->size_nvram;
178
179 sysfs_bin_attr_init(&pdata->nvram_attr);
180 pdata->nvram_attr.attr.name = "nvram";
181 pdata->nvram_attr.attr.mode = S_IRUGO | S_IWUSR;
182 pdata->nvram_attr.read = ds1742_nvram_read;
183 pdata->nvram_attr.write = ds1742_nvram_write;
184 pdata->nvram_attr.size = pdata->size_nvram;
185
186 /* turn RTC on if it was not on */
187 ioaddr = pdata->ioaddr_rtc;
188 sec = readb(ioaddr + RTC_SECONDS);
189 if (sec & RTC_STOP) {
190 sec &= RTC_SECONDS_MASK;
191 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
192 writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
193 writeb(sec, ioaddr + RTC_SECONDS);
194 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
195 }
196 if (!(readb(ioaddr + RTC_DAY) & RTC_BATT_FLAG))
197 dev_warn(&pdev->dev, "voltage-low detected.\n");
198
199 pdata->last_jiffies = jiffies;
200 platform_set_drvdata(pdev, pdata);
201 rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
202 &ds1742_rtc_ops, THIS_MODULE);
203 if (IS_ERR(rtc))
204 return PTR_ERR(rtc);
205
206 ret = sysfs_create_bin_file(&pdev->dev.kobj, &pdata->nvram_attr);
207 if (ret)
208 dev_err(&pdev->dev, "Unable to create sysfs entry: %s\n",
209 pdata->nvram_attr.attr.name);
210
211 return 0;
212}
213
214static int ds1742_rtc_remove(struct platform_device *pdev)
215{
216 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
217
218 sysfs_remove_bin_file(&pdev->dev.kobj, &pdata->nvram_attr);
219 return 0;
220}
221
222static const struct of_device_id __maybe_unused ds1742_rtc_of_match[] = {
223 { .compatible = "maxim,ds1742", },
224 { }
225};
226MODULE_DEVICE_TABLE(of, ds1742_rtc_of_match);
227
228static struct platform_driver ds1742_rtc_driver = {
229 .probe = ds1742_rtc_probe,
230 .remove = ds1742_rtc_remove,
231 .driver = {
232 .name = "rtc-ds1742",
233 .of_match_table = of_match_ptr(ds1742_rtc_of_match),
234 },
235};
236
237module_platform_driver(ds1742_rtc_driver);
238
239MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
240MODULE_DESCRIPTION("Dallas DS1742 RTC driver");
241MODULE_LICENSE("GPL");
242MODULE_VERSION(DRV_VERSION);
243MODULE_ALIAS("platform:rtc-ds1742");
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/of_device.h>
20#include <linux/platform_device.h>
21#include <linux/io.h>
22#include <linux/module.h>
23
24#define RTC_SIZE 8
25
26#define RTC_CONTROL 0
27#define RTC_CENTURY 0
28#define RTC_SECONDS 1
29#define RTC_MINUTES 2
30#define RTC_HOURS 3
31#define RTC_DAY 4
32#define RTC_DATE 5
33#define RTC_MONTH 6
34#define RTC_YEAR 7
35
36#define RTC_CENTURY_MASK 0x3f
37#define RTC_SECONDS_MASK 0x7f
38#define RTC_DAY_MASK 0x07
39
40/* Bits in the Control/Century register */
41#define RTC_WRITE 0x80
42#define RTC_READ 0x40
43
44/* Bits in the Seconds register */
45#define RTC_STOP 0x80
46
47/* Bits in the Day register */
48#define RTC_BATT_FLAG 0x80
49
50struct rtc_plat_data {
51 void __iomem *ioaddr_nvram;
52 void __iomem *ioaddr_rtc;
53 unsigned long last_jiffies;
54};
55
56static int ds1742_rtc_set_time(struct device *dev, struct rtc_time *tm)
57{
58 struct rtc_plat_data *pdata = dev_get_drvdata(dev);
59 void __iomem *ioaddr = pdata->ioaddr_rtc;
60 u8 century;
61
62 century = bin2bcd((tm->tm_year + 1900) / 100);
63
64 writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
65
66 writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR);
67 writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH);
68 writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY);
69 writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE);
70 writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS);
71 writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES);
72 writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS);
73
74 /* RTC_CENTURY and RTC_CONTROL share same register */
75 writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY);
76 writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
77 return 0;
78}
79
80static int ds1742_rtc_read_time(struct device *dev, struct rtc_time *tm)
81{
82 struct rtc_plat_data *pdata = dev_get_drvdata(dev);
83 void __iomem *ioaddr = pdata->ioaddr_rtc;
84 unsigned int year, month, day, hour, minute, second, week;
85 unsigned int century;
86
87 /* give enough time to update RTC in case of continuous read */
88 if (pdata->last_jiffies == jiffies)
89 msleep(1);
90 pdata->last_jiffies = jiffies;
91 writeb(RTC_READ, ioaddr + RTC_CONTROL);
92 second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;
93 minute = readb(ioaddr + RTC_MINUTES);
94 hour = readb(ioaddr + RTC_HOURS);
95 day = readb(ioaddr + RTC_DATE);
96 week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;
97 month = readb(ioaddr + RTC_MONTH);
98 year = readb(ioaddr + RTC_YEAR);
99 century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
100 writeb(0, ioaddr + RTC_CONTROL);
101 tm->tm_sec = bcd2bin(second);
102 tm->tm_min = bcd2bin(minute);
103 tm->tm_hour = bcd2bin(hour);
104 tm->tm_mday = bcd2bin(day);
105 tm->tm_wday = bcd2bin(week);
106 tm->tm_mon = bcd2bin(month) - 1;
107 /* year is 1900 + tm->tm_year */
108 tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900;
109
110 return 0;
111}
112
113static const struct rtc_class_ops ds1742_rtc_ops = {
114 .read_time = ds1742_rtc_read_time,
115 .set_time = ds1742_rtc_set_time,
116};
117
118static int ds1742_nvram_read(void *priv, unsigned int pos, void *val,
119 size_t bytes)
120{
121 struct rtc_plat_data *pdata = priv;
122 void __iomem *ioaddr = pdata->ioaddr_nvram;
123 u8 *buf = val;
124
125 for (; bytes; bytes--)
126 *buf++ = readb(ioaddr + pos++);
127 return 0;
128}
129
130static int ds1742_nvram_write(void *priv, unsigned int pos, void *val,
131 size_t bytes)
132{
133 struct rtc_plat_data *pdata = priv;
134 void __iomem *ioaddr = pdata->ioaddr_nvram;
135 u8 *buf = val;
136
137 for (; bytes; bytes--)
138 writeb(*buf++, ioaddr + pos++);
139 return 0;
140}
141
142static int ds1742_rtc_probe(struct platform_device *pdev)
143{
144 struct rtc_device *rtc;
145 struct resource *res;
146 unsigned int cen, sec;
147 struct rtc_plat_data *pdata;
148 void __iomem *ioaddr;
149 int ret = 0;
150 struct nvmem_config nvmem_cfg = {
151 .name = "ds1742_nvram",
152 .reg_read = ds1742_nvram_read,
153 .reg_write = ds1742_nvram_write,
154 };
155
156
157 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
158 if (!pdata)
159 return -ENOMEM;
160
161 ioaddr = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
162 if (IS_ERR(ioaddr))
163 return PTR_ERR(ioaddr);
164
165 pdata->ioaddr_nvram = ioaddr;
166 pdata->ioaddr_rtc = ioaddr + resource_size(res) - RTC_SIZE;
167
168 nvmem_cfg.size = resource_size(res) - RTC_SIZE;
169 nvmem_cfg.priv = pdata;
170
171 /* turn RTC on if it was not on */
172 ioaddr = pdata->ioaddr_rtc;
173 sec = readb(ioaddr + RTC_SECONDS);
174 if (sec & RTC_STOP) {
175 sec &= RTC_SECONDS_MASK;
176 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
177 writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
178 writeb(sec, ioaddr + RTC_SECONDS);
179 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
180 }
181 if (!(readb(ioaddr + RTC_DAY) & RTC_BATT_FLAG))
182 dev_warn(&pdev->dev, "voltage-low detected.\n");
183
184 pdata->last_jiffies = jiffies;
185 platform_set_drvdata(pdev, pdata);
186
187 rtc = devm_rtc_allocate_device(&pdev->dev);
188 if (IS_ERR(rtc))
189 return PTR_ERR(rtc);
190
191 rtc->ops = &ds1742_rtc_ops;
192
193 ret = devm_rtc_register_device(rtc);
194 if (ret)
195 return ret;
196
197 devm_rtc_nvmem_register(rtc, &nvmem_cfg);
198
199 return 0;
200}
201
202static const struct of_device_id __maybe_unused ds1742_rtc_of_match[] = {
203 { .compatible = "maxim,ds1742", },
204 { }
205};
206MODULE_DEVICE_TABLE(of, ds1742_rtc_of_match);
207
208static struct platform_driver ds1742_rtc_driver = {
209 .probe = ds1742_rtc_probe,
210 .driver = {
211 .name = "rtc-ds1742",
212 .of_match_table = of_match_ptr(ds1742_rtc_of_match),
213 },
214};
215
216module_platform_driver(ds1742_rtc_driver);
217
218MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
219MODULE_DESCRIPTION("Dallas DS1742 RTC driver");
220MODULE_LICENSE("GPL");
221MODULE_ALIAS("platform:rtc-ds1742");