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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
44#define RTC_WRITE 0x80
45#define RTC_READ 0x40
46
47
48#define RTC_STOP 0x80
49
50
51#define RTC_BATT_FLAG 0x80
52
53struct rtc_plat_data {
54 void __iomem *ioaddr_nvram;
55 void __iomem *ioaddr_rtc;
56 size_t size_nvram;
57 unsigned long last_jiffies;
58 struct bin_attribute nvram_attr;
59};
60
61static int ds1742_rtc_set_time(struct device *dev, struct rtc_time *tm)
62{
63 struct platform_device *pdev = to_platform_device(dev);
64 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
65 void __iomem *ioaddr = pdata->ioaddr_rtc;
66 u8 century;
67
68 century = bin2bcd((tm->tm_year + 1900) / 100);
69
70 writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
71
72 writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR);
73 writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH);
74 writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY);
75 writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE);
76 writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS);
77 writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES);
78 writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS);
79
80
81 writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY);
82 writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
83 return 0;
84}
85
86static int ds1742_rtc_read_time(struct device *dev, struct rtc_time *tm)
87{
88 struct platform_device *pdev = to_platform_device(dev);
89 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
90 void __iomem *ioaddr = pdata->ioaddr_rtc;
91 unsigned int year, month, day, hour, minute, second, week;
92 unsigned int century;
93
94
95 if (pdata->last_jiffies == jiffies)
96 msleep(1);
97 pdata->last_jiffies = jiffies;
98 writeb(RTC_READ, ioaddr + RTC_CONTROL);
99 second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;
100 minute = readb(ioaddr + RTC_MINUTES);
101 hour = readb(ioaddr + RTC_HOURS);
102 day = readb(ioaddr + RTC_DATE);
103 week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;
104 month = readb(ioaddr + RTC_MONTH);
105 year = readb(ioaddr + RTC_YEAR);
106 century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
107 writeb(0, ioaddr + RTC_CONTROL);
108 tm->tm_sec = bcd2bin(second);
109 tm->tm_min = bcd2bin(minute);
110 tm->tm_hour = bcd2bin(hour);
111 tm->tm_mday = bcd2bin(day);
112 tm->tm_wday = bcd2bin(week);
113 tm->tm_mon = bcd2bin(month) - 1;
114
115 tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900;
116
117 return rtc_valid_tm(tm);
118}
119
120static const struct rtc_class_ops ds1742_rtc_ops = {
121 .read_time = ds1742_rtc_read_time,
122 .set_time = ds1742_rtc_set_time,
123};
124
125static ssize_t ds1742_nvram_read(struct file *filp, struct kobject *kobj,
126 struct bin_attribute *bin_attr,
127 char *buf, loff_t pos, size_t size)
128{
129 struct device *dev = container_of(kobj, struct device, kobj);
130 struct platform_device *pdev = to_platform_device(dev);
131 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
132 void __iomem *ioaddr = pdata->ioaddr_nvram;
133 ssize_t count;
134
135 for (count = 0; count < size; count++)
136 *buf++ = readb(ioaddr + pos++);
137 return count;
138}
139
140static ssize_t ds1742_nvram_write(struct file *filp, struct kobject *kobj,
141 struct bin_attribute *bin_attr,
142 char *buf, loff_t pos, size_t size)
143{
144 struct device *dev = container_of(kobj, struct device, kobj);
145 struct platform_device *pdev = to_platform_device(dev);
146 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
147 void __iomem *ioaddr = pdata->ioaddr_nvram;
148 ssize_t count;
149
150 for (count = 0; count < size; count++)
151 writeb(*buf++, ioaddr + pos++);
152 return count;
153}
154
155static int ds1742_rtc_probe(struct platform_device *pdev)
156{
157 struct rtc_device *rtc;
158 struct resource *res;
159 unsigned int cen, sec;
160 struct rtc_plat_data *pdata;
161 void __iomem *ioaddr;
162 int ret = 0;
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->size_nvram = resource_size(res) - RTC_SIZE;
175 pdata->ioaddr_rtc = ioaddr + pdata->size_nvram;
176
177 sysfs_bin_attr_init(&pdata->nvram_attr);
178 pdata->nvram_attr.attr.name = "nvram";
179 pdata->nvram_attr.attr.mode = S_IRUGO | S_IWUSR;
180 pdata->nvram_attr.read = ds1742_nvram_read;
181 pdata->nvram_attr.write = ds1742_nvram_write;
182 pdata->nvram_attr.size = pdata->size_nvram;
183
184
185 ioaddr = pdata->ioaddr_rtc;
186 sec = readb(ioaddr + RTC_SECONDS);
187 if (sec & RTC_STOP) {
188 sec &= RTC_SECONDS_MASK;
189 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
190 writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
191 writeb(sec, ioaddr + RTC_SECONDS);
192 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
193 }
194 if (!(readb(ioaddr + RTC_DAY) & RTC_BATT_FLAG))
195 dev_warn(&pdev->dev, "voltage-low detected.\n");
196
197 pdata->last_jiffies = jiffies;
198 platform_set_drvdata(pdev, pdata);
199 rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
200 &ds1742_rtc_ops, THIS_MODULE);
201 if (IS_ERR(rtc))
202 return PTR_ERR(rtc);
203
204 ret = sysfs_create_bin_file(&pdev->dev.kobj, &pdata->nvram_attr);
205 if (ret)
206 dev_err(&pdev->dev, "Unable to create sysfs entry: %s\n",
207 pdata->nvram_attr.attr.name);
208
209 return 0;
210}
211
212static int ds1742_rtc_remove(struct platform_device *pdev)
213{
214 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
215
216 sysfs_remove_bin_file(&pdev->dev.kobj, &pdata->nvram_attr);
217 return 0;
218}
219
220static const struct of_device_id __maybe_unused ds1742_rtc_of_match[] = {
221 { .compatible = "maxim,ds1742", },
222 { }
223};
224MODULE_DEVICE_TABLE(of, ds1742_rtc_of_match);
225
226static struct platform_driver ds1742_rtc_driver = {
227 .probe = ds1742_rtc_probe,
228 .remove = ds1742_rtc_remove,
229 .driver = {
230 .name = "rtc-ds1742",
231 .of_match_table = of_match_ptr(ds1742_rtc_of_match),
232 },
233};
234
235module_platform_driver(ds1742_rtc_driver);
236
237MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
238MODULE_DESCRIPTION("Dallas DS1742 RTC driver");
239MODULE_LICENSE("GPL");
240MODULE_ALIAS("platform:rtc-ds1742");
241
