2 * ST M48T86 / Dallas DS12887 RTC driver
3 * Copyright (c) 2006 Tower Technologies
5 * Author: Alessandro Zummo <a.zummo@towertech.it>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
11 * This drivers only supports the clock running in BCD and 24H mode.
12 * If it will be ever adapted to binary and 12H mode, care must be taken
13 * to not introduce bugs.
16 #include <linux/module.h>
17 #include <linux/rtc.h>
18 #include <linux/platform_device.h>
19 #include <linux/platform_data/rtc-m48t86.h>
20 #include <linux/bcd.h>
23 #define M48T86_SEC 0x00
24 #define M48T86_SECALRM 0x01
25 #define M48T86_MIN 0x02
26 #define M48T86_MINALRM 0x03
27 #define M48T86_HOUR 0x04
28 #define M48T86_HOURALRM 0x05
29 #define M48T86_DOW 0x06 /* 1 = sunday */
30 #define M48T86_DOM 0x07
31 #define M48T86_MONTH 0x08 /* 1 - 12 */
32 #define M48T86_YEAR 0x09 /* 0 - 99 */
35 #define M48T86_B_SET BIT(7)
36 #define M48T86_B_DM BIT(2)
37 #define M48T86_B_H24 BIT(1)
40 #define M48T86_D_VRT BIT(7)
41 #define M48T86_NVRAM(x) (0x0e + (x))
42 #define M48T86_NVRAM_LEN 114
44 struct m48t86_rtc_info {
45 void __iomem *index_reg;
46 void __iomem *data_reg;
47 struct rtc_device *rtc;
48 struct m48t86_ops *ops;
51 static unsigned char m48t86_readb(struct device *dev, unsigned long addr)
53 struct m48t86_rtc_info *info = dev_get_drvdata(dev);
57 value = info->ops->readbyte(addr);
59 writeb(addr, info->index_reg);
60 value = readb(info->data_reg);
65 static void m48t86_writeb(struct device *dev,
66 unsigned char value, unsigned long addr)
68 struct m48t86_rtc_info *info = dev_get_drvdata(dev);
71 info->ops->writebyte(value, addr);
73 writeb(addr, info->index_reg);
74 writeb(value, info->data_reg);
78 static int m48t86_rtc_read_time(struct device *dev, struct rtc_time *tm)
82 reg = m48t86_readb(dev, M48T86_B);
84 if (reg & M48T86_B_DM) {
85 /* data (binary) mode */
86 tm->tm_sec = m48t86_readb(dev, M48T86_SEC);
87 tm->tm_min = m48t86_readb(dev, M48T86_MIN);
88 tm->tm_hour = m48t86_readb(dev, M48T86_HOUR) & 0x3f;
89 tm->tm_mday = m48t86_readb(dev, M48T86_DOM);
91 tm->tm_mon = m48t86_readb(dev, M48T86_MONTH) - 1;
92 tm->tm_year = m48t86_readb(dev, M48T86_YEAR) + 100;
93 tm->tm_wday = m48t86_readb(dev, M48T86_DOW);
96 tm->tm_sec = bcd2bin(m48t86_readb(dev, M48T86_SEC));
97 tm->tm_min = bcd2bin(m48t86_readb(dev, M48T86_MIN));
98 tm->tm_hour = bcd2bin(m48t86_readb(dev, M48T86_HOUR) &
100 tm->tm_mday = bcd2bin(m48t86_readb(dev, M48T86_DOM));
102 tm->tm_mon = bcd2bin(m48t86_readb(dev, M48T86_MONTH)) - 1;
103 tm->tm_year = bcd2bin(m48t86_readb(dev, M48T86_YEAR)) + 100;
104 tm->tm_wday = bcd2bin(m48t86_readb(dev, M48T86_DOW));
107 /* correct the hour if the clock is in 12h mode */
108 if (!(reg & M48T86_B_H24))
109 if (m48t86_readb(dev, M48T86_HOUR) & 0x80)
112 return rtc_valid_tm(tm);
115 static int m48t86_rtc_set_time(struct device *dev, struct rtc_time *tm)
119 reg = m48t86_readb(dev, M48T86_B);
121 /* update flag and 24h mode */
122 reg |= M48T86_B_SET | M48T86_B_H24;
123 m48t86_writeb(dev, reg, M48T86_B);
125 if (reg & M48T86_B_DM) {
126 /* data (binary) mode */
127 m48t86_writeb(dev, tm->tm_sec, M48T86_SEC);
128 m48t86_writeb(dev, tm->tm_min, M48T86_MIN);
129 m48t86_writeb(dev, tm->tm_hour, M48T86_HOUR);
130 m48t86_writeb(dev, tm->tm_mday, M48T86_DOM);
131 m48t86_writeb(dev, tm->tm_mon + 1, M48T86_MONTH);
132 m48t86_writeb(dev, tm->tm_year % 100, M48T86_YEAR);
133 m48t86_writeb(dev, tm->tm_wday, M48T86_DOW);
136 m48t86_writeb(dev, bin2bcd(tm->tm_sec), M48T86_SEC);
137 m48t86_writeb(dev, bin2bcd(tm->tm_min), M48T86_MIN);
138 m48t86_writeb(dev, bin2bcd(tm->tm_hour), M48T86_HOUR);
139 m48t86_writeb(dev, bin2bcd(tm->tm_mday), M48T86_DOM);
140 m48t86_writeb(dev, bin2bcd(tm->tm_mon + 1), M48T86_MONTH);
141 m48t86_writeb(dev, bin2bcd(tm->tm_year % 100), M48T86_YEAR);
142 m48t86_writeb(dev, bin2bcd(tm->tm_wday), M48T86_DOW);
146 reg &= ~M48T86_B_SET;
147 m48t86_writeb(dev, reg, M48T86_B);
152 static int m48t86_rtc_proc(struct device *dev, struct seq_file *seq)
156 reg = m48t86_readb(dev, M48T86_B);
158 seq_printf(seq, "mode\t\t: %s\n",
159 (reg & M48T86_B_DM) ? "binary" : "bcd");
161 reg = m48t86_readb(dev, M48T86_D);
163 seq_printf(seq, "battery\t\t: %s\n",
164 (reg & M48T86_D_VRT) ? "ok" : "exhausted");
169 static const struct rtc_class_ops m48t86_rtc_ops = {
170 .read_time = m48t86_rtc_read_time,
171 .set_time = m48t86_rtc_set_time,
172 .proc = m48t86_rtc_proc,
175 static ssize_t m48t86_nvram_read(struct file *filp, struct kobject *kobj,
176 struct bin_attribute *attr,
177 char *buf, loff_t off, size_t count)
179 struct device *dev = kobj_to_dev(kobj);
182 for (i = 0; i < count; i++)
183 buf[i] = m48t86_readb(dev, M48T86_NVRAM(off + i));
188 static ssize_t m48t86_nvram_write(struct file *filp, struct kobject *kobj,
189 struct bin_attribute *attr,
190 char *buf, loff_t off, size_t count)
192 struct device *dev = kobj_to_dev(kobj);
195 for (i = 0; i < count; i++)
196 m48t86_writeb(dev, buf[i], M48T86_NVRAM(off + i));
201 static BIN_ATTR(nvram, 0644, m48t86_nvram_read, m48t86_nvram_write,
204 static int m48t86_rtc_probe(struct platform_device *pdev)
206 struct m48t86_rtc_info *info;
209 info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
213 info->ops = dev_get_platdata(&pdev->dev);
215 struct resource *res;
217 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
220 info->index_reg = devm_ioremap_resource(&pdev->dev, res);
221 if (IS_ERR(info->index_reg))
222 return PTR_ERR(info->index_reg);
224 res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
227 info->data_reg = devm_ioremap_resource(&pdev->dev, res);
228 if (IS_ERR(info->data_reg))
229 return PTR_ERR(info->data_reg);
232 dev_set_drvdata(&pdev->dev, info);
234 info->rtc = devm_rtc_device_register(&pdev->dev, "m48t86",
235 &m48t86_rtc_ops, THIS_MODULE);
236 if (IS_ERR(info->rtc))
237 return PTR_ERR(info->rtc);
239 /* read battery status */
240 reg = m48t86_readb(&pdev->dev, M48T86_D);
241 dev_info(&pdev->dev, "battery %s\n",
242 (reg & M48T86_D_VRT) ? "ok" : "exhausted");
244 if (device_create_bin_file(&pdev->dev, &bin_attr_nvram))
245 dev_err(&pdev->dev, "failed to create nvram sysfs entry\n");
250 static int m48t86_rtc_remove(struct platform_device *pdev)
252 device_remove_bin_file(&pdev->dev, &bin_attr_nvram);
256 static struct platform_driver m48t86_rtc_platform_driver = {
258 .name = "rtc-m48t86",
260 .probe = m48t86_rtc_probe,
261 .remove = m48t86_rtc_remove,
264 module_platform_driver(m48t86_rtc_platform_driver);
266 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
267 MODULE_DESCRIPTION("M48T86 RTC driver");
268 MODULE_LICENSE("GPL");
269 MODULE_ALIAS("platform:rtc-m48t86");