[linux-2.6-block.git] / drivers / rtc / rtc-m48t35.c

/*
 * Driver for the SGS-Thomson M48T35 Timekeeper RAM chip
 *
 * Copyright (C) 2000 Silicon Graphics, Inc.
 * Written by Ulf Carlsson (ulfc@engr.sgi.com)
 *
 * Copyright (C) 2008 Thomas Bogendoerfer
 *
 * Based on code written by Paul Gortmaker.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 */

#include <linux/module.h>
#include <linux/rtc.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/bcd.h>
#include <linux/io.h>
#include <linux/err.h>

#define DRV_VERSION		"1.0"

struct m48t35_rtc {
	u8	pad[0x7ff8];    /* starts at 0x7ff8 */
	u8	control;
	u8	sec;
	u8	min;
	u8	hour;
	u8	day;
	u8	date;
	u8	month;
	u8	year;
};

#define M48T35_RTC_SET		0x80
#define M48T35_RTC_READ		0x40

struct m48t35_priv {
	struct rtc_device *rtc;
	struct m48t35_rtc __iomem *reg;
	size_t size;
	unsigned long baseaddr;
	spinlock_t lock;
};

static int m48t35_read_time(struct device *dev, struct rtc_time *tm)
{
	struct m48t35_priv *priv = dev_get_drvdata(dev);
	u8 control;

	/*
	 * Only the values that we read from the RTC are set. We leave
	 * tm_wday, tm_yday and tm_isdst untouched. Even though the
	 * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
	 * by the RTC when initially set to a non-zero value.
	 */
	spin_lock_irq(&priv->lock);
	control = readb(&priv->reg->control);
	writeb(control | M48T35_RTC_READ, &priv->reg->control);
	tm->tm_sec = readb(&priv->reg->sec);
	tm->tm_min = readb(&priv->reg->min);
	tm->tm_hour = readb(&priv->reg->hour);
	tm->tm_mday = readb(&priv->reg->date);
	tm->tm_mon = readb(&priv->reg->month);
	tm->tm_year = readb(&priv->reg->year);
	writeb(control, &priv->reg->control);
	spin_unlock_irq(&priv->lock);

	tm->tm_sec = bcd2bin(tm->tm_sec);
	tm->tm_min = bcd2bin(tm->tm_min);
	tm->tm_hour = bcd2bin(tm->tm_hour);
	tm->tm_mday = bcd2bin(tm->tm_mday);
	tm->tm_mon = bcd2bin(tm->tm_mon);
	tm->tm_year = bcd2bin(tm->tm_year);

	/*
	 * Account for differences between how the RTC uses the values
	 * and how they are defined in a struct rtc_time;
	 */
	tm->tm_year += 70;
	if (tm->tm_year <= 69)
		tm->tm_year += 100;

	tm->tm_mon--;
	return rtc_valid_tm(tm);
}

static int m48t35_set_time(struct device *dev, struct rtc_time *tm)
{
	struct m48t35_priv *priv = dev_get_drvdata(dev);
	unsigned char mon, day, hrs, min, sec;
	unsigned int yrs;
	u8 control;

	yrs = tm->tm_year + 1900;
	mon = tm->tm_mon + 1;   /* tm_mon starts at zero */
	day = tm->tm_mday;
	hrs = tm->tm_hour;
	min = tm->tm_min;
	sec = tm->tm_sec;

	if (yrs < 1970)
		return -EINVAL;

	yrs -= 1970;
	if (yrs > 255)    /* They are unsigned */
		return -EINVAL;

	if (yrs > 169)
		return -EINVAL;

	if (yrs >= 100)
		yrs -= 100;

	sec = bin2bcd(sec);
	min = bin2bcd(min);
	hrs = bin2bcd(hrs);
	day = bin2bcd(day);
	mon = bin2bcd(mon);
	yrs = bin2bcd(yrs);

	spin_lock_irq(&priv->lock);
	control = readb(&priv->reg->control);
	writeb(control | M48T35_RTC_SET, &priv->reg->control);
	writeb(yrs, &priv->reg->year);
	writeb(mon, &priv->reg->month);
	writeb(day, &priv->reg->date);
	writeb(hrs, &priv->reg->hour);
	writeb(min, &priv->reg->min);
	writeb(sec, &priv->reg->sec);
	writeb(control, &priv->reg->control);
	spin_unlock_irq(&priv->lock);
	return 0;
}

static const struct rtc_class_ops m48t35_ops = {
	.read_time	= m48t35_read_time,
	.set_time	= m48t35_set_time,
};

static int m48t35_probe(struct platform_device *pdev)
{
	struct resource *res;
	struct m48t35_priv *priv;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res)
		return -ENODEV;
	priv = devm_kzalloc(&pdev->dev, sizeof(struct m48t35_priv), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	priv->size = resource_size(res);
	/*
	 * kludge: remove the #ifndef after ioc3 resource
	 * conflicts are resolved
	 */
#ifndef CONFIG_SGI_IP27
	if (!devm_request_mem_region(&pdev->dev, res->start, priv->size,
				     pdev->name))
		return -EBUSY;
#endif
	priv->baseaddr = res->start;
	priv->reg = devm_ioremap(&pdev->dev, priv->baseaddr, priv->size);
	if (!priv->reg)
		return -ENOMEM;

	spin_lock_init(&priv->lock);

	platform_set_drvdata(pdev, priv);

	priv->rtc = devm_rtc_device_register(&pdev->dev, "m48t35",
				  &m48t35_ops, THIS_MODULE);
	return PTR_ERR_OR_ZERO(priv->rtc);
}

static struct platform_driver m48t35_platform_driver = {
	.driver		= {
		.name	= "rtc-m48t35",
	},
	.probe		= m48t35_probe,
};

module_platform_driver(m48t35_platform_driver);

MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>");
MODULE_DESCRIPTION("M48T35 RTC driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);
MODULE_ALIAS("platform:rtc-m48t35");
Commit	Line	Data
d1dbd82e TB	1	/*
	2	* Driver for the SGS-Thomson M48T35 Timekeeper RAM chip
	3	*
	4	* Copyright (C) 2000 Silicon Graphics, Inc.
	5	* Written by Ulf Carlsson (ulfc@engr.sgi.com)
	6	*
	7	* Copyright (C) 2008 Thomas Bogendoerfer
	8	*
	9	* Based on code written by Paul Gortmaker.
	10	*
	11	* This program is free software; you can redistribute it and/or modify it
	12	* under the terms of the GNU General Public License as published by the
	13	* Free Software Foundation; either version 2 of the License, or (at your
	14	* option) any later version.
	15	*/
	16
	17	#include <linux/module.h>
	18	#include <linux/rtc.h>
5a0e3ad6	19	#include <linux/slab.h>
d1dbd82e TB	20	#include <linux/platform_device.h>
d1dbd82e TB	21	#include <linux/bcd.h>
d7a6119f	22	#include <linux/io.h>
8ff7b7d9	23	#include <linux/err.h>
d1dbd82e TB	24
	25	#define DRV_VERSION "1.0"
	26
	27	struct m48t35_rtc {
	28	u8 pad[0x7ff8]; /* starts at 0x7ff8 */
	29	u8 control;
	30	u8 sec;
	31	u8 min;
	32	u8 hour;
	33	u8 day;
	34	u8 date;
	35	u8 month;
	36	u8 year;
	37	};
	38
	39	#define M48T35_RTC_SET 0x80
	40	#define M48T35_RTC_READ 0x40
	41
	42	struct m48t35_priv {
	43	struct rtc_device *rtc;
	44	struct m48t35_rtc __iomem *reg;
	45	size_t size;
	46	unsigned long baseaddr;
	47	spinlock_t lock;
	48	};
	49
	50	static int m48t35_read_time(struct device dev, struct rtc_time tm)
	51	{
	52	struct m48t35_priv *priv = dev_get_drvdata(dev);
	53	u8 control;
	54
	55	/*
	56	* Only the values that we read from the RTC are set. We leave
	57	* tm_wday, tm_yday and tm_isdst untouched. Even though the
	58	* RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
	59	* by the RTC when initially set to a non-zero value.
	60	*/
	61	spin_lock_irq(&priv->lock);
	62	control = readb(&priv->reg->control);
	63	writeb(control \| M48T35_RTC_READ, &priv->reg->control);
	64	tm->tm_sec = readb(&priv->reg->sec);
	65	tm->tm_min = readb(&priv->reg->min);
	66	tm->tm_hour = readb(&priv->reg->hour);
	67	tm->tm_mday = readb(&priv->reg->date);
	68	tm->tm_mon = readb(&priv->reg->month);
	69	tm->tm_year = readb(&priv->reg->year);
	70	writeb(control, &priv->reg->control);
	71	spin_unlock_irq(&priv->lock);
	72
	73	tm->tm_sec = bcd2bin(tm->tm_sec);
	74	tm->tm_min = bcd2bin(tm->tm_min);
	75	tm->tm_hour = bcd2bin(tm->tm_hour);
	76	tm->tm_mday = bcd2bin(tm->tm_mday);
	77	tm->tm_mon = bcd2bin(tm->tm_mon);
	78	tm->tm_year = bcd2bin(tm->tm_year);
	79
	80	/*
	81	* Account for differences between how the RTC uses the values
	82	* and how they are defined in a struct rtc_time;
	83	*/
	84	tm->tm_year += 70;
	85	if (tm->tm_year <= 69)
	86	tm->tm_year += 100;
	87
88	tm->tm_mon--;
89	return rtc_valid_tm(tm);
90	}
91
92	static int m48t35_set_time(struct device dev, struct rtc_time tm)
93	{
94	struct m48t35_priv *priv = dev_get_drvdata(dev);
95	unsigned char mon, day, hrs, min, sec;
96	unsigned int yrs;
97	u8 control;
98
99	yrs = tm->tm_year + 1900;
100	mon = tm->tm_mon + 1; /* tm_mon starts at zero */
101	day = tm->tm_mday;
102	hrs = tm->tm_hour;
103	min = tm->tm_min;
104	sec = tm->tm_sec;
105
106	if (yrs < 1970)
107	return -EINVAL;
108
109	yrs -= 1970;
110	if (yrs > 255) /* They are unsigned */
111	return -EINVAL;
112
113	if (yrs > 169)
114	return -EINVAL;
115
116	if (yrs >= 100)
117	yrs -= 100;
118
119	sec = bin2bcd(sec);
120	min = bin2bcd(min);
121	hrs = bin2bcd(hrs);
122	day = bin2bcd(day);
123	mon = bin2bcd(mon);
124	yrs = bin2bcd(yrs);
125
126	spin_lock_irq(&priv->lock);
127	control = readb(&priv->reg->control);
128	writeb(control \| M48T35_RTC_SET, &priv->reg->control);
129	writeb(yrs, &priv->reg->year);
130	writeb(mon, &priv->reg->month);
131	writeb(day, &priv->reg->date);
132	writeb(hrs, &priv->reg->hour);
133	writeb(min, &priv->reg->min);
134	writeb(sec, &priv->reg->sec);
135	writeb(control, &priv->reg->control);
136	spin_unlock_irq(&priv->lock);
137	return 0;
138	}
139
140	static const struct rtc_class_ops m48t35_ops = {
141	.read_time = m48t35_read_time,
142	.set_time = m48t35_set_time,
143	};
144
5a167f45	145	static int m48t35_probe(struct platform_device *pdev)
d1dbd82e	146	{
d1dbd82e TB	147	struct resource *res;
d1dbd82e TB	148	struct m48t35_priv *priv;
d1dbd82e TB	149
	150	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	151	if (!res)
	152	return -ENODEV;
4f58cd9b	153	priv = devm_kzalloc(&pdev->dev, sizeof(struct m48t35_priv), GFP_KERNEL);
d1dbd82e TB	154	if (!priv)
	155	return -ENOMEM;
	156
28f65c11	157	priv->size = resource_size(res);
d1dbd82e TB	158	/*
	159	* kludge: remove the #ifndef after ioc3 resource
	160	* conflicts are resolved
	161	*/
	162	#ifndef CONFIG_SGI_IP27
4f58cd9b SK	163	if (!devm_request_mem_region(&pdev->dev, res->start, priv->size,
	164	pdev->name))
	165	return -EBUSY;
d1dbd82e TB	166	#endif
d1dbd82e TB	167	priv->baseaddr = res->start;
4f58cd9b SK	168	priv->reg = devm_ioremap(&pdev->dev, priv->baseaddr, priv->size);
	169	if (!priv->reg)
	170	return -ENOMEM;
b74d2caa	171
d1dbd82e	172	spin_lock_init(&priv->lock);
b74d2caa AZ	173
	174	platform_set_drvdata(pdev, priv);
	175
4f58cd9b	176	priv->rtc = devm_rtc_device_register(&pdev->dev, "m48t35",
d1dbd82e	177	&m48t35_ops, THIS_MODULE);
dac30a98	178	return PTR_ERR_OR_ZERO(priv->rtc);
d1dbd82e TB	179	}
d1dbd82e TB	180
d1dbd82e TB	181	static struct platform_driver m48t35_platform_driver = {
	182	.driver = {
	183	.name = "rtc-m48t35",
d1dbd82e TB	184	},
d1dbd82e TB	185	.probe = m48t35_probe,
d1dbd82e TB	186	};
d1dbd82e TB	187
0c4eae66	188	module_platform_driver(m48t35_platform_driver);
d1dbd82e TB	189
	190	MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>");
	191	MODULE_DESCRIPTION("M48T35 RTC driver");
	192	MODULE_LICENSE("GPL");
	193	MODULE_VERSION(DRV_VERSION);
	194	MODULE_ALIAS("platform:rtc-m48t35");