Message-ID: <62DDBB9E5E23CC4A929EE46F9427CEAF1C0C21@BUDMLVEM04.e2k.ad.ge.com>
Date:	Wed, 18 Jul 2007 11:12:43 +0200
From:	"Hommel, Thomas (GE Indust, GE Fanuc)" <Thomas.Hommel@...anuc.com>
To:	<p_gortmaker@...oo.com>
Cc:	<linux-kernel@...r.kernel.org>
Subject: [PATCH] rtc: Add support for STK17TA8 chip

From: Thomas Hommel <thomas.hommel@...anuc.com>

This patch adds support for the Simtek STK17TA8 timekeeping chip.
Signed-off-by: Thomas Hommel <thomas.hommel@...anuc.com>

---
The STK17TA8 is quite similar to the DS1553, but differs in register
layout and in various control bits in the registers. I chose to make
this a new driver to avoid confusion in the code and to not get lost in
#ifdefs.

diff -uprN -X linux/Documentation/dontdiff
linux-2.6.22.1-vanilla/drivers/rtc/Kconfig linux/drivers/rtc/Kconfig
--- linux-2.6.22.1-vanilla/drivers/rtc/Kconfig	2007-07-09
10:53:32.000000000 +0200
+++ linux/drivers/rtc/Kconfig	2007-07-18 09:48:26.000000000 +0200
@@ -272,6 +272,16 @@ config RTC_DRV_DS1553
 	  This driver can also be built as a module. If so, the module
 	  will be called rtc-ds1553.
 
+config RTC_DRV_STK17TA8
+	tristate "Simtek STK17TA8"
+	depends on RTC_CLASS
+	help
+	  If you say yes here you get support for the
+	  Simtek STK17TA8 timekeeping chip.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called rtc-stk17ta8.
+
 config RTC_DRV_DS1742
 	tristate "Dallas DS1742/1743"
 	depends on RTC_CLASS
diff -uprN -X linux/Documentation/dontdiff
linux-2.6.22.1-vanilla/drivers/rtc/Makefile linux/drivers/rtc/Makefile
--- linux-2.6.22.1-vanilla/drivers/rtc/Makefile	2007-07-09
10:53:32.000000000 +0200
+++ linux/drivers/rtc/Makefile	2007-07-09 11:25:46.000000000 +0200
@@ -30,6 +30,7 @@ obj-$(CONFIG_RTC_DRV_S3C)	+= rtc-s3c.o
 obj-$(CONFIG_RTC_DRV_RS5C348)	+= rtc-rs5c348.o
 obj-$(CONFIG_RTC_DRV_M48T86)	+= rtc-m48t86.o
 obj-$(CONFIG_RTC_DRV_DS1553)	+= rtc-ds1553.o
+obj-$(CONFIG_RTC_DRV_STK17TA8)	+= rtc-stk17ta8.o
 obj-$(CONFIG_RTC_DRV_RS5C313)	+= rtc-rs5c313.o
 obj-$(CONFIG_RTC_DRV_EP93XX)	+= rtc-ep93xx.o
 obj-$(CONFIG_RTC_DRV_SA1100)	+= rtc-sa1100.o
diff -uprN -X linux/Documentation/dontdiff
linux-2.6.22.1-vanilla/drivers/rtc/rtc-stk17ta8.c
linux/drivers/rtc/rtc-stk17ta8.c
--- linux-2.6.22.1-vanilla/drivers/rtc/rtc-stk17ta8.c	1970-01-01
01:00:00.000000000 +0100
+++ linux/drivers/rtc/rtc-stk17ta8.c	2007-07-18 10:42:20.000000000
+0200
@@ -0,0 +1,420 @@
+/*
+ * A RTC driver for the Simtek STK17TA8
+ *
+ * By Thomas Hommel <thomas.hommel@...anuc.com>
+ *
+ * Based on the DS1553 driver from
+ * Atsushi Nemoto <anemo@....ocn.ne.jp>
+ *
+ * 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.
+ */
+
+#include <linux/bcd.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/jiffies.h>
+#include <linux/interrupt.h>
+#include <linux/rtc.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+
+#define DRV_VERSION "0.1"
+
+#define RTC_REG_SIZE		0x20000
+#define RTC_OFFSET		0x1fff0
+
+#define RTC_FLAGS		(RTC_OFFSET + 0)
+#define RTC_CENTURY		(RTC_OFFSET + 1)
+#define RTC_SECONDS_ALARM	(RTC_OFFSET + 2)
+#define RTC_MINUTES_ALARM	(RTC_OFFSET + 3)
+#define RTC_HOURS_ALARM		(RTC_OFFSET + 4)
+#define RTC_DATE_ALARM		(RTC_OFFSET + 5)
+#define RTC_INTERRUPTS		(RTC_OFFSET + 6)
+#define RTC_WATCHDOG		(RTC_OFFSET + 7)
+#define RTC_CALIBRATION		(RTC_OFFSET + 8)
+#define RTC_SECONDS		(RTC_OFFSET + 9)
+#define RTC_MINUTES		(RTC_OFFSET + 10)
+#define RTC_HOURS		(RTC_OFFSET + 11)
+#define RTC_DAY			(RTC_OFFSET + 12)
+#define RTC_DATE		(RTC_OFFSET + 13)
+#define RTC_MONTH		(RTC_OFFSET + 14)
+#define RTC_YEAR		(RTC_OFFSET + 15)
+
+#define RTC_SECONDS_MASK	0x7f
+#define RTC_DAY_MASK		0x07
+#define RTC_CAL_MASK		0x3f
+
+/* Bits in the Calibration register */
+#define RTC_STOP		0x80
+
+/* Bits in the Flags register */
+#define RTC_FLAGS_AF		0x40
+#define RTC_FLAGS_PF		0x20
+#define RTC_WRITE		0x02
+#define RTC_READ		0x01
+
+/* Bits in the Interrupts register */
+#define RTC_INTS_AIE		0x40
+
+struct rtc_plat_data {
+	struct rtc_device *rtc;
+	void __iomem *ioaddr;
+	unsigned long baseaddr;
+	unsigned long last_jiffies;
+	int irq;
+	unsigned int irqen;
+	int alrm_sec;
+	int alrm_min;
+	int alrm_hour;
+	int alrm_mday;
+};
+
+static int stk17ta8_rtc_set_time(struct device *dev, struct rtc_time
*tm)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
+	void __iomem *ioaddr = pdata->ioaddr;
+	u8 flags;
+
+	flags = readb(pdata->ioaddr + RTC_FLAGS);
+	writeb(flags | RTC_WRITE, pdata->ioaddr + RTC_FLAGS);
+
+	writeb(BIN2BCD(tm->tm_year % 100), ioaddr + RTC_YEAR);
+	writeb(BIN2BCD(tm->tm_mon + 1), ioaddr + RTC_MONTH);
+	writeb(BIN2BCD(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY);
+	writeb(BIN2BCD(tm->tm_mday), ioaddr + RTC_DATE);
+	writeb(BIN2BCD(tm->tm_hour), ioaddr + RTC_HOURS);
+	writeb(BIN2BCD(tm->tm_min), ioaddr + RTC_MINUTES);
+	writeb(BIN2BCD(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr +
RTC_SECONDS);
+	writeb(BIN2BCD((tm->tm_year + 1900) / 100), ioaddr +
RTC_CENTURY);
+
+	writeb(flags & ~RTC_WRITE, pdata->ioaddr + RTC_FLAGS);
+	return 0;
+}
+
+static int stk17ta8_rtc_read_time(struct device *dev, struct rtc_time
*tm)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
+	void __iomem *ioaddr = pdata->ioaddr;
+	unsigned int year, month, day, hour, minute, second, week;
+	unsigned int century;
+	u8 flags;
+
+	/* give enough time to update RTC in case of continuous read */
+	if (pdata->last_jiffies == jiffies)
+		msleep(1);
+	pdata->last_jiffies = jiffies;
+
+	flags = readb(pdata->ioaddr + RTC_FLAGS);
+	writeb(flags | RTC_READ, ioaddr + RTC_FLAGS);
+	second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;
+	minute = readb(ioaddr + RTC_MINUTES);
+	hour = readb(ioaddr + RTC_HOURS);
+	day = readb(ioaddr + RTC_DATE);
+	week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;
+	month = readb(ioaddr + RTC_MONTH);
+	year = readb(ioaddr + RTC_YEAR);
+	century = readb(ioaddr + RTC_CENTURY);
+	writeb(flags & ~RTC_READ, ioaddr + RTC_FLAGS);
+	tm->tm_sec = BCD2BIN(second);
+	tm->tm_min = BCD2BIN(minute);
+	tm->tm_hour = BCD2BIN(hour);
+	tm->tm_mday = BCD2BIN(day);
+	tm->tm_wday = BCD2BIN(week);
+	tm->tm_mon = BCD2BIN(month) - 1;
+	/* year is 1900 + tm->tm_year */
+	tm->tm_year = BCD2BIN(year) + BCD2BIN(century) * 100 - 1900;
+
+	if (rtc_valid_tm(tm) < 0) {
+		dev_err(dev, "retrieved date/time is not valid.\n");
+		rtc_time_to_tm(0, tm);
+	}
+	return 0;
+}
+
+static void stk17ta8_rtc_update_alarm(struct rtc_plat_data *pdata)
+{
+	void __iomem *ioaddr = pdata->ioaddr;
+	unsigned long irqflags;
+	u8 flags;
+
+	spin_lock_irqsave(&pdata->rtc->irq_lock, irqflags);
+
+	flags = readb(ioaddr + RTC_FLAGS);
+	writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS);
+
+	writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
+	       0x80 : BIN2BCD(pdata->alrm_mday),
+	       ioaddr + RTC_DATE_ALARM);
+	writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
+	       0x80 : BIN2BCD(pdata->alrm_hour),
+	       ioaddr + RTC_HOURS_ALARM);
+	writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
+	       0x80 : BIN2BCD(pdata->alrm_min),
+	       ioaddr + RTC_MINUTES_ALARM);
+	writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
+	       0x80 : BIN2BCD(pdata->alrm_sec),
+	       ioaddr + RTC_SECONDS_ALARM);
+	writeb(pdata->irqen ? RTC_INTS_AIE : 0, ioaddr +
RTC_INTERRUPTS);
+	readb(ioaddr + RTC_FLAGS);	/* clear interrupts */
+	writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS);
+	spin_unlock_irqrestore(&pdata->rtc->irq_lock, irqflags);
+}
+
+static int stk17ta8_rtc_set_alarm(struct device *dev, struct rtc_wkalrm
*alrm)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
+
+	if (pdata->irq < 0)
+		return -EINVAL;
+	pdata->alrm_mday = alrm->time.tm_mday;
+	pdata->alrm_hour = alrm->time.tm_hour;
+	pdata->alrm_min = alrm->time.tm_min;
+	pdata->alrm_sec = alrm->time.tm_sec;
+	if (alrm->enabled)
+		pdata->irqen |= RTC_AF;
+	stk17ta8_rtc_update_alarm(pdata);
+	return 0;
+}
+
+static int stk17ta8_rtc_read_alarm(struct device *dev, struct
rtc_wkalrm *alrm)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
+
+	if (pdata->irq < 0)
+		return -EINVAL;
+	alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 :
pdata->alrm_mday;
+	alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 :
pdata->alrm_hour;
+	alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;
+	alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;
+	alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;
+	return 0;
+}
+
+static irqreturn_t stk17ta8_rtc_interrupt(int irq, void *dev_id)
+{
+	struct platform_device *pdev = dev_id;
+	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
+	void __iomem *ioaddr = pdata->ioaddr;
+	unsigned long events = RTC_IRQF;
+
+	/* read and clear interrupt */
+	if (!(readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF))
+		return IRQ_NONE;
+	if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80)
+		events |= RTC_UF;
+	else
+		events |= RTC_AF;
+	rtc_update_irq(pdata->rtc, 1, events);
+	return IRQ_HANDLED;
+}
+
+static void stk17ta8_rtc_release(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
+
+	if (pdata->irq >= 0) {
+		pdata->irqen = 0;
+		stk17ta8_rtc_update_alarm(pdata);
+	}
+}
+
+static int stk17ta8_rtc_ioctl(struct device *dev, unsigned int cmd,
+			    unsigned long arg)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
+
+	if (pdata->irq < 0)
+		return -ENOIOCTLCMD; /* fall back into rtc-dev's
emulation */
+	switch (cmd) {
+	case RTC_AIE_OFF:
+		pdata->irqen &= ~RTC_AF;
+		stk17ta8_rtc_update_alarm(pdata);
+		break;
+	case RTC_AIE_ON:
+		pdata->irqen |= RTC_AF;
+		stk17ta8_rtc_update_alarm(pdata);
+		break;
+	default:
+		return -ENOIOCTLCMD;
+	}
+	return 0;
+}
+
+static const struct rtc_class_ops stk17ta8_rtc_ops = {
+	.read_time	= stk17ta8_rtc_read_time,
+	.set_time	= stk17ta8_rtc_set_time,
+	.read_alarm	= stk17ta8_rtc_read_alarm,
+	.set_alarm	= stk17ta8_rtc_set_alarm,
+	.release	= stk17ta8_rtc_release,
+	.ioctl		= stk17ta8_rtc_ioctl,
+};
+
+static ssize_t stk17ta8_nvram_read(struct kobject *kobj, char *buf,
+				 loff_t pos, size_t size)
+{
+	struct platform_device *pdev =
+		to_platform_device(container_of(kobj, struct device,
kobj));
+	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
+	void __iomem *ioaddr = pdata->ioaddr;
+	ssize_t count;
+
+	for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
+		*buf++ = readb(ioaddr + pos++);
+	return count;
+}
+
+static ssize_t stk17ta8_nvram_write(struct kobject *kobj, char *buf,
+				  loff_t pos, size_t size)
+{
+	struct platform_device *pdev =
+		to_platform_device(container_of(kobj, struct device,
kobj));
+	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
+	void __iomem *ioaddr = pdata->ioaddr;
+	ssize_t count;
+
+	for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
+		writeb(*buf++, ioaddr + pos++);
+	return count;
+}
+
+static struct bin_attribute stk17ta8_nvram_attr = {
+	.attr = {
+		.name = "nvram",
+		.mode = S_IRUGO | S_IWUGO,
+		.owner = THIS_MODULE,
+	},
+	.size = RTC_OFFSET,
+	.read = stk17ta8_nvram_read,
+	.write = stk17ta8_nvram_write,
+};
+
+static int __init stk17ta8_rtc_probe(struct platform_device *pdev)
+{
+	struct rtc_device *rtc;
+	struct resource *res;
+	unsigned int cal;
+	unsigned int flags;
+	struct rtc_plat_data *pdata = NULL;
+	void __iomem *ioaddr = NULL;
+	int ret = 0;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -ENODEV;
+
+	pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
+	if (!pdata)
+		return -ENOMEM;
+	pdata->irq = -1;
+	if (!request_mem_region(res->start, RTC_REG_SIZE, pdev->name)) {
+		ret = -EBUSY;
+		goto out;
+	}
+	pdata->baseaddr = res->start;
+	ioaddr = ioremap(pdata->baseaddr, RTC_REG_SIZE);
+	if (!ioaddr) {
+		ret = -ENOMEM;
+		goto out;
+	}
+	pdata->ioaddr = ioaddr;
+	pdata->irq = platform_get_irq(pdev, 0);
+
+	/* turn RTC on if it was not on */
+	cal = readb(ioaddr + RTC_CALIBRATION);
+	if (cal & RTC_STOP) {
+		cal &= RTC_CAL_MASK;
+		flags = readb(ioaddr + RTC_FLAGS);
+		writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS);
+		writeb(cal, ioaddr + RTC_CALIBRATION);
+		writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS);
+	}
+	if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_PF)
+		dev_warn(&pdev->dev, "voltage-low detected.\n");
+
+	if (pdata->irq >= 0) {
+		writeb(0, ioaddr + RTC_INTERRUPTS);
+		if (request_irq(pdata->irq, stk17ta8_rtc_interrupt,
+				IRQF_DISABLED | IRQF_SHARED,
+				pdev->name, pdev) < 0) {
+			dev_warn(&pdev->dev, "interrupt not
available.\n");
+			pdata->irq = -1;
+		}
+	}
+
+	rtc = rtc_device_register(pdev->name, &pdev->dev,
+				  &stk17ta8_rtc_ops, THIS_MODULE);
+	if (IS_ERR(rtc)) {
+		ret = PTR_ERR(rtc);
+		goto out;
+	}
+	pdata->rtc = rtc;
+	pdata->last_jiffies = jiffies;
+	platform_set_drvdata(pdev, pdata);
+	ret = sysfs_create_bin_file(&pdev->dev.kobj,
&stk17ta8_nvram_attr);
+	if (ret)
+		goto out;
+	return 0;
+ out:
+	if (pdata->rtc)
+		rtc_device_unregister(pdata->rtc);
+	if (pdata->irq >= 0)
+		free_irq(pdata->irq, pdev);
+	if (ioaddr)
+		iounmap(ioaddr);
+	if (pdata->baseaddr)
+		release_mem_region(pdata->baseaddr, RTC_REG_SIZE);
+	kfree(pdata);
+	return ret;
+}
+
+static int __devexit stk17ta8_rtc_remove(struct platform_device *pdev)
+{
+	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
+
+	sysfs_remove_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr);
+	rtc_device_unregister(pdata->rtc);
+	if (pdata->irq >= 0) {
+		writeb(0, pdata->ioaddr + RTC_INTERRUPTS);
+		free_irq(pdata->irq, pdev);
+	}
+	iounmap(pdata->ioaddr);
+	release_mem_region(pdata->baseaddr, RTC_REG_SIZE);
+	kfree(pdata);
+	return 0;
+}
+
+static struct platform_driver stk17ta8_rtc_driver = {
+	.probe		= stk17ta8_rtc_probe,
+	.remove		= __devexit_p(stk17ta8_rtc_remove),
+	.driver		= {
+		.name	= "stk17ta8",
+		.owner	= THIS_MODULE,
+	},
+};
+
+static __init int stk17ta8_init(void)
+{
+	return platform_driver_register(&stk17ta8_rtc_driver);
+}
+
+static __exit void stk17ta8_exit(void)
+{
+	return platform_driver_unregister(&stk17ta8_rtc_driver);
+}
+
+module_init(stk17ta8_init);
+module_exit(stk17ta8_exit);
+
+MODULE_AUTHOR("Thomas Hommel <thomas.hommel@...anuc.com>");
+MODULE_DESCRIPTION("Simtek STK17TA8 RTC driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);
-
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