/*
* ST M48T86 / Dallas DS12887 RTC driver
* Copyright (c) 2006 Tower Technologies
*
* Author: Alessandro Zummo <a.zummo@towertech.it>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This drivers only supports the clock running in BCD and 24H mode.
* If it will be ever adapted to binary and 12H mode, care must be taken
* to not introduce bugs.
*/
#include <linux/module.h>
#include <linux/rtc.h>
#include <linux/platform_device.h>
#include <linux/platform_data/rtc-m48t86.h>
#include <linux/bcd.h>
#include <linux/io.h>
#define M48T86_SEC 0x00
#define M48T86_SECALRM 0x01
#define M48T86_MIN 0x02
#define M48T86_MINALRM 0x03
#define M48T86_HOUR 0x04
#define M48T86_HOURALRM 0x05
#define M48T86_DOW 0x06 /* 1 = sunday */
#define M48T86_DOM 0x07
#define M48T86_MONTH 0x08 /* 1 - 12 */
#define M48T86_YEAR 0x09 /* 0 - 99 */
#define M48T86_A 0x0a
#define M48T86_B 0x0b
#define M48T86_B_SET BIT(7)
#define M48T86_B_DM BIT(2)
#define M48T86_B_H24 BIT(1)
#define M48T86_C 0x0c
#define M48T86_D 0x0d
#define M48T86_D_VRT BIT(7)
struct m48t86_rtc_info {
void __iomem *index_reg;
void __iomem *data_reg;
struct rtc_device *rtc;
struct m48t86_ops *ops;
};
static unsigned char m48t86_readb(struct device *dev, unsigned long addr)
{
struct m48t86_rtc_info *info = dev_get_drvdata(dev);
unsigned char value;
if (info->ops) {
value = info->ops->readbyte(addr);
} else {
writeb(addr, info->index_reg);
value = readb(info->data_reg);
}
return value;
}
static void m48t86_writeb(struct device *dev,
unsigned char value, unsigned long addr)
{
struct m48t86_rtc_info *info = dev_get_drvdata(dev);
if (info->ops) {
info->ops->writebyte(value, addr);
} else {
writeb(addr, info->index_reg);
writeb(value, info->data_reg);
}
}
static int m48t86_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
unsigned char reg;
reg = m48t86_readb(dev, M48T86_B);
if (reg & M48T86_B_DM) {
/* data (binary) mode */
tm->tm_sec = m48t86_readb(dev, M48T86_SEC);
tm->tm_min = m48t86_readb(dev, M48T86_MIN);
tm->tm_hour = m48t86_readb(dev, M48T86_HOUR) & 0x3f;
tm->tm_mday = m48t86_readb(dev, M48T86_DOM);
/* tm_mon is 0-11 */
tm->tm_mon = m48t86_readb(dev, M48T86_MONTH) - 1;
tm->tm_year = m48t86_readb(dev, M48T86_YEAR) + 100;
tm->tm_wday = m48t86_readb(dev, M48T86_DOW);
} else {
/* bcd mode */
tm->tm_sec = bcd2bin(m48t86_readb(dev, M48T86_SEC));
tm->tm_min = bcd2bin(m48t86_readb(dev, M48T86_MIN));
tm->tm_hour = bcd2bin(m48t86_readb(dev, M48T86_HOUR) &
0x3f);
tm->tm_mday = bcd2bin(m48t86_readb(dev, M48T86_DOM));
/* tm_mon is 0-11 */
tm->tm_mon = bcd2bin(m48t86_readb(dev, M48T86_MONTH)) - 1;
tm->tm_year = bcd2bin(m48t86_readb(dev, M48T86_YEAR)) + 100;
tm->tm_wday = bcd2bin(m48t86_readb(dev, M48T86_DOW));
}
/* correct the hour if the clock is in 12h mode */
if (!(reg & M48T86_B_H24))
if (m48t86_readb(dev, M48T86_HOUR) & 0x80)
tm->tm_hour += 12;
return rtc_valid_tm(tm);
}
static int m48t86_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
unsigned char reg;
reg = m48t86_readb(dev, M48T86_B);
/* update flag and 24h mode */
reg |= M48T86_B_SET | M48T86_B_H24;
m48t86_writeb(dev, reg, M48T86_B);
if (reg & M48T86_B_DM) {
/* data (binary) mode */
m48t86_writeb(dev, tm->tm_sec, M48T86_SEC);
m48t86_writeb(dev, tm->tm_min, M48T86_MIN);
m48t86_writeb(dev, tm->tm_hour, M48T86_HOUR);
m48t86_writeb(dev, tm->tm_mday, M48T86_DOM);
m48t86_writeb(dev, tm->tm_mon + 1, M48T86_MONTH);
m48t86_writeb(dev, tm->tm_year % 100, M48T86_YEAR);
m48t86_writeb(dev, tm->tm_wday, M48T86_DOW);
} else {
/* bcd mode */
m48t86_writeb(dev, bin2bcd(tm->tm_sec), M48T86_SEC);
m48t86_writeb(dev, bin2bcd(tm->tm_min), M48T86_MIN);
m48t86_writeb(dev, bin2bcd(tm->tm_hour), M48T86_HOUR);
m48t86_writeb(dev, bin2bcd(tm->tm_mday), M48T86_DOM);
m48t86_writeb(dev, bin2bcd(tm->tm_mon + 1), M48T86_MONTH);
m48t86_writeb(dev, bin2bcd(tm->tm_year % 100), M48T86_YEAR);
m48t86_writeb(dev, bin2bcd(tm->tm_wday), M48T86_DOW);
}
/* update ended */
reg &= ~M48T86_B_SET;
m48t86_writeb(dev, reg, M48T86_B);
return 0;
}
static int m48t86_rtc_proc(struct device *dev, struct seq_file *seq)
{
unsigned char reg;
reg = m48t86_readb(dev, M48T86_B);
seq_printf(seq, "mode\t\t: %s\n",
(reg & M48T86_B_DM) ? "binary" : "bcd");
reg = m48t86_readb(dev, M48T86_D);
seq_printf(seq, "battery\t\t: %s\n",
(reg & M48T86_D_VRT) ? "ok" : "exhausted");
return 0;
}
static const struct rtc_class_ops m48t86_rtc_ops = {
.read_time = m48t86_rtc_read_time,
.set_time = m48t86_rtc_set_time,
.proc = m48t86_rtc_proc,
};
static int m48t86_rtc_probe(struct platform_device *pdev)
{
struct m48t86_rtc_info *info;
unsigned char reg;
info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
if (!info)
return -ENOMEM;
info->ops = dev_get_platdata(&pdev->dev);
if (!info->ops) {
struct resource *res;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res)
return -ENODEV;
info->index_reg = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(info->index_reg))
return PTR_ERR(info->index_reg);
res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
if (!res)
return -ENODEV;
info->data_reg = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(info->data_reg))
return PTR_ERR(info->data_reg);
}
dev_set_drvdata(&pdev->dev, info);
info->rtc = devm_rtc_device_register(&pdev->dev, "m48t86",
&m48t86_rtc_ops, THIS_MODULE);
if (IS_ERR(info->rtc))
return PTR_ERR(info->rtc);
/* read battery status */
reg = m48t86_readb(&pdev->dev, M48T86_D);
dev_info(&pdev->dev, "battery %s\n",
(reg & M48T86_D_VRT) ? "ok" : "exhausted");
return 0;
}
static struct platform_driver m48t86_rtc_platform_driver = {
.driver = {
.name = "rtc-m48t86",
},
.probe = m48t86_rtc_probe,
};
module_platform_driver(m48t86_rtc_platform_driver);
MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
MODULE_DESCRIPTION("M48T86 RTC driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:rtc-m48t86");
