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Subject[PATCH 16/16] RTC subsystem, SA1100/PXA2XX driver
Add an RTC subsystem driver for the ARM SA1100/PXA2XX processor RTC.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Alessandro Zummo <a.zummo@towertech.it>

---
arch/arm/mach-pxa/generic.c | 6
arch/arm/mach-sa1100/generic.c | 6
drivers/rtc/Kconfig | 10 +
drivers/rtc/Makefile | 1
drivers/rtc/rtc-sa1100.c | 392 +++++++++++++++++++++++++++++++++++++++++
5 files changed, 415 insertions(+)

--- linux-rtc.orig/drivers/rtc/Kconfig 2006-03-05 17:03:39.000000000 +0100
+++ linux-rtc/drivers/rtc/Kconfig 2006-03-05 17:03:39.000000000 +0100
@@ -128,6 +128,16 @@ config RTC_DRV_EP93XX
will be called rtc-ep93xx.


+config RTC_DRV_SA1100
+ bool "SA11x0/PXA2xx RTC support"
+ depends on ARCH_SA1100 || ARCH_PXA
+ help
+ If you say Y here you will get access to the real time clock
+ built into your SA11x0 or PXA2xx CPU.
+
+ To compile this driver as a module, choose M here: the
+ module will be called rtc-sa1100.
+
config RTC_DRV_TEST
tristate "Test driver/device"
depends on RTC_CLASS
--- linux-rtc.orig/drivers/rtc/Makefile 2006-03-05 17:03:39.000000000 +0100
+++ linux-rtc/drivers/rtc/Makefile 2006-03-05 17:03:39.000000000 +0100
@@ -17,3 +17,4 @@ obj-$(CONFIG_RTC_DRV_DS1672) += rtc-ds16
obj-$(CONFIG_RTC_DRV_PCF8563) += rtc-pcf8563.o
obj-$(CONFIG_RTC_DRV_RS5C372) += rtc-rs5c372.o
obj-$(CONFIG_RTC_DRV_EP93XX) += rtc-ep93xx.o
+obj-$(CONFIG_RTC_DRV_SA1100) += rtc-sa1100.o
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-rtc/drivers/rtc/rtc-sa1100.c 2006-03-05 17:03:39.000000000 +0100
@@ -0,0 +1,392 @@
+/*
+ * Real Time Clock interface for StrongARM SA1x00 and XScale PXA2xx
+ *
+ * Copyright (c) 2000 Nils Faerber
+ *
+ * Based on rtc.c by Paul Gortmaker
+ *
+ * Original Driver by Nils Faerber <nils@kernelconcepts.de>
+ *
+ * Modifications from:
+ * CIH <cih@coventive.com>
+ * Nicolas Pitre <nico@cam.org>
+ * Andrew Christian <andrew.christian@hp.com>
+ *
+ * Converted to the RTC subsystem and Driver Model
+ * by Richard Purdie <rpurdie@rpsys.net>
+ *
+ * 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. *
+ * 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/platform_device.h>
+#include <linux/module.h>
+#include <linux/rtc.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/interrupt.h>
+#include <linux/string.h>
+#include <linux/pm.h>
+
+#include <asm/bitops.h>
+#include <asm/hardware.h>
+#include <asm/irq.h>
+#include <asm/rtc.h>
+
+#ifdef CONFIG_ARCH_PXA
+#include <asm/arch/pxa-regs.h>
+#endif
+
+#define TIMER_FREQ CLOCK_TICK_RATE
+#define RTC_DEF_DIVIDER 32768 - 1
+#define RTC_DEF_TRIM 0
+
+static unsigned long rtc_freq = 1024;
+static struct rtc_time rtc_alarm;
+static spinlock_t sa1100_rtc_lock = SPIN_LOCK_UNLOCKED;
+
+static int rtc_update_alarm(struct rtc_time *alrm)
+{
+ struct rtc_time alarm_tm, now_tm;
+ unsigned long now, time;
+ int ret;
+
+ do {
+ now = RCNR;
+ rtc_time_to_tm(now, &now_tm);
+ rtc_next_alarm_time(&alarm_tm, &now_tm, alrm);
+ ret = rtc_tm_to_time(&alarm_tm, &time);
+ if (ret != 0)
+ break;
+
+ RTSR = RTSR & (RTSR_HZE|RTSR_ALE|RTSR_AL);
+ RTAR = time;
+ } while (now != RCNR);
+
+ return ret;
+}
+
+static irqreturn_t sa1100_rtc_interrupt(int irq, void *dev_id,
+ struct pt_regs *regs)
+{
+ struct platform_device *pdev = to_platform_device(dev_id);
+ struct rtc_device *rtc = platform_get_drvdata(pdev);
+ unsigned int rtsr;
+ unsigned long events = 0;
+
+ spin_lock(&sa1100_rtc_lock);
+
+ rtsr = RTSR;
+ /* clear interrupt sources */
+ RTSR = 0;
+ RTSR = (RTSR_AL | RTSR_HZ) & (rtsr >> 2);
+
+ /* clear alarm interrupt if it has occurred */
+ if (rtsr & RTSR_AL)
+ rtsr &= ~RTSR_ALE;
+ RTSR = rtsr & (RTSR_ALE | RTSR_HZE);
+
+ /* update irq data & counter */
+ if (rtsr & RTSR_AL)
+ events |= RTC_AF | RTC_IRQF;
+ if (rtsr & RTSR_HZ)
+ events |= RTC_UF | RTC_IRQF;
+
+ rtc_update_irq(&rtc->class_dev, 1, events);
+
+ if (rtsr & RTSR_AL && rtc_periodic_alarm(&rtc_alarm))
+ rtc_update_alarm(&rtc_alarm);
+
+ spin_unlock(&sa1100_rtc_lock);
+
+ return IRQ_HANDLED;
+}
+
+static int rtc_timer1_count;
+
+static irqreturn_t timer1_interrupt(int irq, void *dev_id,
+ struct pt_regs *regs)
+{
+ struct platform_device *pdev = to_platform_device(dev_id);
+ struct rtc_device *rtc = platform_get_drvdata(pdev);
+
+ /*
+ * If we match for the first time, rtc_timer1_count will be 1.
+ * Otherwise, we wrapped around (very unlikely but
+ * still possible) so compute the amount of missed periods.
+ * The match reg is updated only when the data is actually retrieved
+ * to avoid unnecessary interrupts.
+ */
+ OSSR = OSSR_M1; /* clear match on timer1 */
+
+ rtc_update_irq(&rtc->class_dev, rtc_timer1_count, RTC_PF | RTC_IRQF);
+
+ if (rtc_timer1_count == 1)
+ rtc_timer1_count = (rtc_freq * ((1<<30)/(TIMER_FREQ>>2)));
+
+ return IRQ_HANDLED;
+}
+
+static int sa1100_rtc_read_callback(struct device *dev, int data)
+{
+ if (data & RTC_PF) {
+ /* interpolate missed periods and set match for the next */
+ unsigned long period = TIMER_FREQ/rtc_freq;
+ unsigned long oscr = OSCR;
+ unsigned long osmr1 = OSMR1;
+ unsigned long missed = (oscr - osmr1)/period;
+ data += missed << 8;
+ OSSR = OSSR_M1; /* clear match on timer 1 */
+ OSMR1 = osmr1 + (missed + 1)*period;
+ /* Ensure we didn't miss another match in the mean time.
+ * Here we compare (match - OSCR) 8 instead of 0 --
+ * see comment in pxa_timer_interrupt() for explanation.
+ */
+ while( (signed long)((osmr1 = OSMR1) - OSCR) <= 8 ) {
+ data += 0x100;
+ OSSR = OSSR_M1; /* clear match on timer 1 */
+ OSMR1 = osmr1 + period;
+ }
+ }
+ return data;
+}
+
+static int sa1100_rtc_open(struct device *dev)
+{
+ int ret;
+
+ ret = request_irq(IRQ_RTC1Hz, sa1100_rtc_interrupt, SA_INTERRUPT,
+ "rtc 1Hz", dev);
+ if (ret) {
+ printk(KERN_ERR "rtc: IRQ%d already in use.\n", IRQ_RTC1Hz);
+ goto fail_ui;
+ }
+ ret = request_irq(IRQ_RTCAlrm, sa1100_rtc_interrupt, SA_INTERRUPT,
+ "rtc Alrm", dev);
+ if (ret) {
+ printk(KERN_ERR "rtc: IRQ%d already in use.\n", IRQ_RTCAlrm);
+ goto fail_ai;
+ }
+ ret = request_irq(IRQ_OST1, timer1_interrupt, SA_INTERRUPT,
+ "rtc timer", dev);
+ if (ret) {
+ printk(KERN_ERR "rtc: IRQ%d already in use.\n", IRQ_OST1);
+ goto fail_pi;
+ }
+ return 0;
+
+ fail_pi:
+ free_irq(IRQ_RTCAlrm, NULL);
+ fail_ai:
+ free_irq(IRQ_RTC1Hz, NULL);
+ fail_ui:
+ return ret;
+}
+
+static void sa1100_rtc_release(struct device *dev)
+{
+ spin_lock_irq(&sa1100_rtc_lock);
+ RTSR = 0;
+ OIER &= ~OIER_E1;
+ OSSR = OSSR_M1;
+ spin_unlock_irq(&sa1100_rtc_lock);
+
+ free_irq(IRQ_OST1, dev);
+ free_irq(IRQ_RTCAlrm, dev);
+ free_irq(IRQ_RTC1Hz, dev);
+}
+
+
+static int sa1100_rtc_ioctl(struct device *dev, unsigned int cmd,
+ unsigned long arg)
+{
+ switch(cmd) {
+ case RTC_AIE_OFF:
+ spin_lock_irq(&sa1100_rtc_lock);
+ RTSR &= ~RTSR_ALE;
+ spin_unlock_irq(&sa1100_rtc_lock);
+ return 0;
+ case RTC_AIE_ON:
+ spin_lock_irq(&sa1100_rtc_lock);
+ RTSR |= RTSR_ALE;
+ spin_unlock_irq(&sa1100_rtc_lock);
+ return 0;
+ case RTC_UIE_OFF:
+ spin_lock_irq(&sa1100_rtc_lock);
+ RTSR &= ~RTSR_HZE;
+ spin_unlock_irq(&sa1100_rtc_lock);
+ return 0;
+ case RTC_UIE_ON:
+ spin_lock_irq(&sa1100_rtc_lock);
+ RTSR |= RTSR_HZE;
+ spin_unlock_irq(&sa1100_rtc_lock);
+ return 0;
+ case RTC_PIE_OFF:
+ spin_lock_irq(&sa1100_rtc_lock);
+ OIER &= ~OIER_E1;
+ spin_unlock_irq(&sa1100_rtc_lock);
+ return 0;
+ case RTC_PIE_ON:
+ if ((rtc_freq > 64) && !capable(CAP_SYS_RESOURCE))
+ return -EACCES;
+ spin_lock_irq(&sa1100_rtc_lock);
+ OSMR1 = TIMER_FREQ/rtc_freq + OSCR;
+ OIER |= OIER_E1;
+ rtc_timer1_count = 1;
+ spin_unlock_irq(&sa1100_rtc_lock);
+ return 0;
+ case RTC_IRQP_READ:
+ return put_user(rtc_freq, (unsigned long *)arg);
+ case RTC_IRQP_SET:
+ if (arg < 1 || arg > TIMER_FREQ)
+ return -EINVAL;
+ if ((arg > 64) && (!capable(CAP_SYS_RESOURCE)))
+ return -EACCES;
+ rtc_freq = arg;
+ return 0;
+ }
+ return -EINVAL;
+}
+
+static int sa1100_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ rtc_time_to_tm(RCNR, tm);
+ return 0;
+}
+
+static int sa1100_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ unsigned long time;
+ int ret;
+
+ ret = rtc_tm_to_time(tm, &time);
+ if (ret == 0)
+ RCNR = time;
+ return ret;
+}
+
+static int sa1100_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ memcpy(&alrm->time, &rtc_alarm, sizeof(struct rtc_time));
+ alrm->pending = RTSR & RTSR_AL ? 1 : 0;
+ return 0;
+}
+
+static int sa1100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ int ret;
+
+ spin_lock_irq(&sa1100_rtc_lock);
+ ret = rtc_update_alarm(&alrm->time);
+ if (ret == 0) {
+ memcpy(&rtc_alarm, &alrm->time, sizeof(struct rtc_time));
+
+ if (alrm->enabled)
+ enable_irq_wake(IRQ_RTCAlrm);
+ else
+ disable_irq_wake(IRQ_RTCAlrm);
+ }
+ spin_unlock_irq(&sa1100_rtc_lock);
+
+ return ret;
+}
+
+static int sa1100_rtc_proc(struct device *dev, struct seq_file *seq)
+{
+ seq_printf(seq, "trim/divider\t: 0x%08x\n", RTTR);
+ seq_printf(seq, "alarm_IRQ\t: %s\n",
+ (RTSR & RTSR_ALE) ? "yes" : "no" );
+ seq_printf(seq, "update_IRQ\t: %s\n",
+ (RTSR & RTSR_HZE) ? "yes" : "no");
+ seq_printf(seq, "periodic_IRQ\t: %s\n",
+ (OIER & OIER_E1) ? "yes" : "no");
+ seq_printf(seq, "periodic_freq\t: %ld\n", rtc_freq);
+
+ return 0;
+}
+
+static struct rtc_class_ops sa1100_rtc_ops = {
+ .open = sa1100_rtc_open,
+ .read_callback = sa1100_rtc_read_callback,
+ .release = sa1100_rtc_release,
+ .ioctl = sa1100_rtc_ioctl,
+ .read_time = sa1100_rtc_read_time,
+ .set_time = sa1100_rtc_set_time,
+ .read_alarm = sa1100_rtc_read_alarm,
+ .set_alarm = sa1100_rtc_set_alarm,
+ .proc = sa1100_rtc_proc,
+};
+
+static int sa1100_rtc_probe(struct platform_device *pdev)
+{
+ struct rtc_device *rtc;
+
+ /*
+ * According to the manual we should be able to let RTTR be zero
+ * and then a default diviser for a 32.768KHz clock is used.
+ * Apparently this doesn't work, at least for my SA1110 rev 5.
+ * If the clock divider is uninitialized then reset it to the
+ * default value to get the 1Hz clock.
+ */
+ if (RTTR == 0) {
+ RTTR = RTC_DEF_DIVIDER + (RTC_DEF_TRIM << 16);
+ printk(KERN_WARNING "rtc: warning: initializing default clock divider/trim value\n");
+ /* The current RTC value probably doesn't make sense either */
+ RCNR = 0;
+ }
+
+ rtc = rtc_device_register(pdev->name, &pdev->dev, &sa1100_rtc_ops,
+ THIS_MODULE);
+
+ if (IS_ERR(rtc)) {
+ dev_err(&pdev->dev, "Unable to register the RTC device\n");
+ return PTR_ERR(rtc);
+ }
+
+ platform_set_drvdata(pdev, rtc);
+
+ dev_info(&pdev->dev, "SA11xx/PXA2xx RTC Registered\n");
+
+ return 0;
+}
+
+static int sa1100_rtc_remove(struct platform_device *pdev)
+{
+ struct rtc_device *rtc = platform_get_drvdata(pdev);
+
+ if (rtc)
+ rtc_device_unregister(rtc);
+
+ return 0;
+}
+
+static struct platform_driver sa1100_rtc_driver = {
+ .probe = sa1100_rtc_probe,
+ .remove = sa1100_rtc_remove,
+ .driver = {
+ .name = "sa1100-rtc",
+ },
+};
+
+static int __init sa1100_rtc_init(void)
+{
+ return platform_driver_register(&sa1100_rtc_driver);
+}
+
+static void __exit sa1100_rtc_exit(void)
+{
+ platform_driver_unregister(&sa1100_rtc_driver);
+}
+
+module_init(sa1100_rtc_init);
+module_exit(sa1100_rtc_exit);
+
+MODULE_AUTHOR("Richard Purdie <rpurdie@rpsys.net>");
+MODULE_DESCRIPTION("SA11x0/PXA2xx Realtime Clock Driver (RTC)");
+MODULE_LICENSE("GPL");
--- linux-rtc.orig/arch/arm/mach-pxa/generic.c 2006-03-05 14:40:51.000000000 +0100
+++ linux-rtc/arch/arm/mach-pxa/generic.c 2006-03-05 17:03:39.000000000 +0100
@@ -319,6 +319,11 @@ void __init pxa_set_ficp_info(struct pxa
pxaficp_device.dev.platform_data = info;
}

+static struct platform_device pxartc_device = {
+ .name = "sa1100-rtc",
+ .id = -1,
+};
+
static struct platform_device *devices[] __initdata = {
&pxamci_device,
&udc_device,
@@ -329,6 +334,7 @@ static struct platform_device *devices[]
&pxaficp_device,
&i2c_device,
&i2s_device,
+ &pxartc_device,
};

static int __init pxa_init(void)
--- linux-rtc.orig/arch/arm/mach-sa1100/generic.c 2006-03-05 14:40:51.000000000 +0100
+++ linux-rtc/arch/arm/mach-sa1100/generic.c 2006-03-05 17:03:39.000000000 +0100
@@ -324,6 +324,11 @@ void sa11x0_set_irda_data(struct irda_pl
sa11x0ir_device.dev.platform_data = irda;
}

+static struct platform_device sa11x0rtc_device = {
+ .name = "sa1100-rtc",
+ .id = -1,
+};
+
static struct platform_device *sa11x0_devices[] __initdata = {
&sa11x0udc_device,
&sa11x0uart1_device,
@@ -333,6 +338,7 @@ static struct platform_device *sa11x0_de
&sa11x0pcmcia_device,
&sa11x0fb_device,
&sa11x0mtd_device,
+ &sa11x0rtc_device,
};

static int __init sa1100_init(void)
--
-
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