RTC: M48T35: new RTC driver

This driver replaces the broken ip27-rtc driver in drivers/char and gives back RTC support for SGI IP27 machines. Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Acked-by: Alessandro Zummo <alessandro.zummo@towertech.it> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

RTC: M48T35: new RTC driver
This driver replaces the broken ip27-rtc driver in drivers/char and gives back RTC support for SGI IP27 machines. Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Acked-by: Alessandro Zummo <alessandro.zummo@towertech.it> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Thomas Bogendoerfer · Ralf Baechle
1 parent 3ec066cdb7
Showing 3 changed files with 244 additions and 0 deletions Side-by-side Diff
drivers/rtc/Kconfig
drivers/rtc/Makefile
drivers/rtc/rtc-m48t35.c
@@ -410,6 +410,15 @@
 	  This driver can also be built as a module. If so, the module
 	  will be called rtc-m48t86.
  
+config RTC_DRV_M48T35
+	tristate "ST M48T35"
+	help
+	  If you say Y here you will get support for the
+	  ST M48T35 RTC chip.
+
+	  This driver can also be built as a module, if so, the module
+	  will be called "rtc-m48t35".
+
 config RTC_DRV_M48T59
 	tristate "ST M48T59/M48T08/M48T02"
 	help
@@ -37,6 +37,7 @@
 obj-$(CONFIG_RTC_DRV_ISL1208)	+= rtc-isl1208.o
 obj-$(CONFIG_RTC_DRV_M41T80)	+= rtc-m41t80.o
 obj-$(CONFIG_RTC_DRV_M41T94)	+= rtc-m41t94.o
+obj-$(CONFIG_RTC_DRV_M48T35)	+= rtc-m48t35.o
 obj-$(CONFIG_RTC_DRV_M48T59)	+= rtc-m48t59.o
 obj-$(CONFIG_RTC_DRV_M48T86)	+= rtc-m48t86.o
 obj-$(CONFIG_RTC_DRV_BQ4802)	+= rtc-bq4802.o
+/*
+ * 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/platform_device.h>
+#include <linux/bcd.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 __devinit m48t35_probe(struct platform_device *pdev)
+{
+	struct rtc_device *rtc;
+	struct resource *res;
+	struct m48t35_priv *priv;
+	int ret = 0;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -ENODEV;
+	priv = kzalloc(sizeof(struct m48t35_priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->size = res->end - res->start + 1;
+	/*
+	 * kludge: remove the #ifndef after ioc3 resource
+	 * conflicts are resolved
+	 */
+#ifndef CONFIG_SGI_IP27
+	if (!request_mem_region(res->start, priv->size, pdev->name)) {
+		ret = -EBUSY;
+		goto out;
+	}
+#endif
+	priv->baseaddr = res->start;
+	priv->reg = ioremap(priv->baseaddr, priv->size);
+	if (!priv->reg) {
+		ret = -ENOMEM;
+		goto out;
+	}
+	spin_lock_init(&priv->lock);
+	rtc = rtc_device_register("m48t35", &pdev->dev,
+				  &m48t35_ops, THIS_MODULE);
+	if (IS_ERR(rtc)) {
+		ret = PTR_ERR(rtc);
+		goto out;
+	}
+	priv->rtc = rtc;
+	platform_set_drvdata(pdev, priv);
+	return 0;
+
+out:
+	if (priv->rtc)
+		rtc_device_unregister(priv->rtc);
+	if (priv->reg)
+		iounmap(priv->reg);
+	if (priv->baseaddr)
+		release_mem_region(priv->baseaddr, priv->size);
+	kfree(priv);
+	return ret;
+}
+
+static int __devexit m48t35_remove(struct platform_device *pdev)
+{
+	struct m48t35_priv *priv = platform_get_drvdata(pdev);
+
+	rtc_device_unregister(priv->rtc);
+	iounmap(priv->reg);
+#ifndef CONFIG_SGI_IP27
+	release_mem_region(priv->baseaddr, priv->size);
+#endif
+	kfree(priv);
+	return 0;
+}
+
+static struct platform_driver m48t35_platform_driver = {
+	.driver		= {
+		.name	= "rtc-m48t35",
+		.owner	= THIS_MODULE,
+	},
+	.probe		= m48t35_probe,
+	.remove		= __devexit_p(m48t35_remove),
+};
+
+static int __init m48t35_init(void)
+{
+	return platform_driver_register(&m48t35_platform_driver);
+}
+
+static void __exit m48t35_exit(void)
+{
+	platform_driver_unregister(&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");
+
+module_init(m48t35_init);
+module_exit(m48t35_exit);
...	...	@@ -410,6 +410,15 @@
410	410	This driver can also be built as a module. If so, the module
411	411	will be called rtc-m48t86.
412	412
	413	+config RTC_DRV_M48T35
	414	+ tristate "ST M48T35"
	415	+ help
	416	+ If you say Y here you will get support for the
	417	+ ST M48T35 RTC chip.
	418	+
	419	+ This driver can also be built as a module, if so, the module
	420	+ will be called "rtc-m48t35".
	421	+
413	422	config RTC_DRV_M48T59
414	423	tristate "ST M48T59/M48T08/M48T02"
415	424	help
...	...	@@ -37,6 +37,7 @@
37	37	obj-$(CONFIG_RTC_DRV_ISL1208) += rtc-isl1208.o
38	38	obj-$(CONFIG_RTC_DRV_M41T80) += rtc-m41t80.o
39	39	obj-$(CONFIG_RTC_DRV_M41T94) += rtc-m41t94.o
	40	+obj-$(CONFIG_RTC_DRV_M48T35) += rtc-m48t35.o
40	41	obj-$(CONFIG_RTC_DRV_M48T59) += rtc-m48t59.o
41	42	obj-$(CONFIG_RTC_DRV_M48T86) += rtc-m48t86.o
42	43	obj-$(CONFIG_RTC_DRV_BQ4802) += rtc-bq4802.o
	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>
	19	+#include <linux/platform_device.h>
	20	+#include <linux/bcd.h>
	21	+
	22	+#define DRV_VERSION "1.0"
	23	+
	24	+struct m48t35_rtc {
	25	+ u8 pad[0x7ff8]; /* starts at 0x7ff8 */
	26	+ u8 control;
	27	+ u8 sec;
	28	+ u8 min;
	29	+ u8 hour;
	30	+ u8 day;
	31	+ u8 date;
	32	+ u8 month;
	33	+ u8 year;
	34	+};
	35	+
	36	+#define M48T35_RTC_SET 0x80
	37	+#define M48T35_RTC_READ 0x40
	38	+
	39	+struct m48t35_priv {
	40	+ struct rtc_device *rtc;
	41	+ struct m48t35_rtc __iomem *reg;
	42	+ size_t size;
	43	+ unsigned long baseaddr;
	44	+ spinlock_t lock;
	45	+};
	46	+
	47	+static int m48t35_read_time(struct device dev, struct rtc_time tm)
	48	+{
	49	+ struct m48t35_priv *priv = dev_get_drvdata(dev);
	50	+ u8 control;
	51	+
	52	+ /*
	53	+ * Only the values that we read from the RTC are set. We leave
	54	+ * tm_wday, tm_yday and tm_isdst untouched. Even though the
	55	+ * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
	56	+ * by the RTC when initially set to a non-zero value.
	57	+ */
	58	+ spin_lock_irq(&priv->lock);
	59	+ control = readb(&priv->reg->control);
	60	+ writeb(control \| M48T35_RTC_READ, &priv->reg->control);
	61	+ tm->tm_sec = readb(&priv->reg->sec);
	62	+ tm->tm_min = readb(&priv->reg->min);
	63	+ tm->tm_hour = readb(&priv->reg->hour);
	64	+ tm->tm_mday = readb(&priv->reg->date);
	65	+ tm->tm_mon = readb(&priv->reg->month);
	66	+ tm->tm_year = readb(&priv->reg->year);
	67	+ writeb(control, &priv->reg->control);
	68	+ spin_unlock_irq(&priv->lock);
	69	+
	70	+ tm->tm_sec = bcd2bin(tm->tm_sec);
	71	+ tm->tm_min = bcd2bin(tm->tm_min);
	72	+ tm->tm_hour = bcd2bin(tm->tm_hour);
	73	+ tm->tm_mday = bcd2bin(tm->tm_mday);
	74	+ tm->tm_mon = bcd2bin(tm->tm_mon);
	75	+ tm->tm_year = bcd2bin(tm->tm_year);
	76	+
	77	+ /*
	78	+ * Account for differences between how the RTC uses the values
	79	+ * and how they are defined in a struct rtc_time;
	80	+ */
	81	+ tm->tm_year += 70;
	82	+ if (tm->tm_year <= 69)
	83	+ tm->tm_year += 100;
	84	+
	85	+ tm->tm_mon--;
	86	+ return rtc_valid_tm(tm);
	87	+}
	88	+
	89	+static int m48t35_set_time(struct device dev, struct rtc_time tm)
	90	+{
	91	+ struct m48t35_priv *priv = dev_get_drvdata(dev);
	92	+ unsigned char mon, day, hrs, min, sec;
	93	+ unsigned int yrs;
	94	+ u8 control;
	95	+
	96	+ yrs = tm->tm_year + 1900;
	97	+ mon = tm->tm_mon + 1; /* tm_mon starts at zero */
	98	+ day = tm->tm_mday;
	99	+ hrs = tm->tm_hour;
	100	+ min = tm->tm_min;
	101	+ sec = tm->tm_sec;
	102	+
	103	+ if (yrs < 1970)
	104	+ return -EINVAL;
	105	+
	106	+ yrs -= 1970;
	107	+ if (yrs > 255) /* They are unsigned */
	108	+ return -EINVAL;
	109	+
	110	+ if (yrs > 169)
	111	+ return -EINVAL;
	112	+
	113	+ if (yrs >= 100)
	114	+ yrs -= 100;
	115	+
	116	+ sec = bin2bcd(sec);
	117	+ min = bin2bcd(min);
	118	+ hrs = bin2bcd(hrs);
	119	+ day = bin2bcd(day);
	120	+ mon = bin2bcd(mon);
	121	+ yrs = bin2bcd(yrs);
	122	+
	123	+ spin_lock_irq(&priv->lock);
	124	+ control = readb(&priv->reg->control);
	125	+ writeb(control \| M48T35_RTC_SET, &priv->reg->control);
	126	+ writeb(yrs, &priv->reg->year);
	127	+ writeb(mon, &priv->reg->month);
	128	+ writeb(day, &priv->reg->date);
	129	+ writeb(hrs, &priv->reg->hour);
	130	+ writeb(min, &priv->reg->min);
	131	+ writeb(sec, &priv->reg->sec);
	132	+ writeb(control, &priv->reg->control);
	133	+ spin_unlock_irq(&priv->lock);
	134	+ return 0;
	135	+}
	136	+
	137	+static const struct rtc_class_ops m48t35_ops = {
	138	+ .read_time = m48t35_read_time,
	139	+ .set_time = m48t35_set_time,
	140	+};
	141	+
	142	+static int __devinit m48t35_probe(struct platform_device *pdev)
	143	+{
	144	+ struct rtc_device *rtc;
	145	+ struct resource *res;
	146	+ struct m48t35_priv *priv;
	147	+ int ret = 0;
	148	+
	149	+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	150	+ if (!res)
	151	+ return -ENODEV;
	152	+ priv = kzalloc(sizeof(struct m48t35_priv), GFP_KERNEL);
	153	+ if (!priv)
	154	+ return -ENOMEM;
	155	+
	156	+ priv->size = res->end - res->start + 1;
	157	+ /*
	158	+ * kludge: remove the #ifndef after ioc3 resource
	159	+ * conflicts are resolved
	160	+ */
	161	+#ifndef CONFIG_SGI_IP27
	162	+ if (!request_mem_region(res->start, priv->size, pdev->name)) {
	163	+ ret = -EBUSY;
	164	+ goto out;
	165	+ }
	166	+#endif
	167	+ priv->baseaddr = res->start;
	168	+ priv->reg = ioremap(priv->baseaddr, priv->size);
	169	+ if (!priv->reg) {
	170	+ ret = -ENOMEM;
	171	+ goto out;
	172	+ }
	173	+ spin_lock_init(&priv->lock);
	174	+ rtc = rtc_device_register("m48t35", &pdev->dev,
	175	+ &m48t35_ops, THIS_MODULE);
	176	+ if (IS_ERR(rtc)) {
	177	+ ret = PTR_ERR(rtc);
	178	+ goto out;
	179	+ }
	180	+ priv->rtc = rtc;
	181	+ platform_set_drvdata(pdev, priv);
	182	+ return 0;
	183	+
	184	+out:
	185	+ if (priv->rtc)
	186	+ rtc_device_unregister(priv->rtc);
	187	+ if (priv->reg)
	188	+ iounmap(priv->reg);
	189	+ if (priv->baseaddr)
	190	+ release_mem_region(priv->baseaddr, priv->size);
	191	+ kfree(priv);
	192	+ return ret;
	193	+}
	194	+
	195	+static int __devexit m48t35_remove(struct platform_device *pdev)
	196	+{
	197	+ struct m48t35_priv *priv = platform_get_drvdata(pdev);
	198	+
	199	+ rtc_device_unregister(priv->rtc);
	200	+ iounmap(priv->reg);
	201	+#ifndef CONFIG_SGI_IP27
	202	+ release_mem_region(priv->baseaddr, priv->size);
	203	+#endif
	204	+ kfree(priv);
	205	+ return 0;
	206	+}
	207	+
	208	+static struct platform_driver m48t35_platform_driver = {
	209	+ .driver = {
	210	+ .name = "rtc-m48t35",
	211	+ .owner = THIS_MODULE,
	212	+ },
	213	+ .probe = m48t35_probe,
	214	+ .remove = __devexit_p(m48t35_remove),
	215	+};
	216	+
	217	+static int __init m48t35_init(void)
	218	+{
	219	+ return platform_driver_register(&m48t35_platform_driver);
	220	+}
	221	+
	222	+static void __exit m48t35_exit(void)
	223	+{
	224	+ platform_driver_unregister(&m48t35_platform_driver);
	225	+}
	226	+
	227	+MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>");
	228	+MODULE_DESCRIPTION("M48T35 RTC driver");
	229	+MODULE_LICENSE("GPL");
	230	+MODULE_VERSION(DRV_VERSION);
	231	+MODULE_ALIAS("platform:rtc-m48t35");
	232	+
	233	+module_init(m48t35_init);
	234	+module_exit(m48t35_exit);