- 根目录:
- drivers
- rtc
- rtc-omap.c
/*
* TI OMAP1 Real Time Clock interface for Linux
*
* Copyright (C) 2003 MontaVista Software, Inc.
* Author: George G. Davis <gdavis@mvista.com> or <source@mvista.com>
*
* Copyright (C) 2006 David Brownell (new RTC framework)
*
* 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/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/ioport.h>
#include <linux/delay.h>
#include <linux/rtc.h>
#include <linux/bcd.h>
#include <linux/platform_device.h>
#include <asm/io.h>
/* The OMAP1 RTC is a year/month/day/hours/minutes/seconds BCD clock
* with century-range alarm matching, driven by the 32kHz clock.
*
* The main user-visible ways it differs from PC RTCs are by omitting
* "don't care" alarm fields and sub-second periodic IRQs, and having
* an autoadjust mechanism to calibrate to the true oscillator rate.
*
* Board-specific wiring options include using split power mode with
* RTC_OFF_NOFF used as the reset signal (so the RTC won't be reset),
* and wiring RTC_WAKE_INT (so the RTC alarm can wake the system from
* low power modes) for OMAP1 boards (OMAP-L138 has this built into
* the SoC). See the BOARD-SPECIFIC CUSTOMIZATION comment.
*/
#define OMAP_RTC_BASE 0xfffb4800
/* RTC registers */
#define OMAP_RTC_SECONDS_REG 0x00
#define OMAP_RTC_MINUTES_REG 0x04
#define OMAP_RTC_HOURS_REG 0x08
#define OMAP_RTC_DAYS_REG 0x0C
#define OMAP_RTC_MONTHS_REG 0x10
#define OMAP_RTC_YEARS_REG 0x14
#define OMAP_RTC_WEEKS_REG 0x18
#define OMAP_RTC_ALARM_SECONDS_REG 0x20
#define OMAP_RTC_ALARM_MINUTES_REG 0x24
#define OMAP_RTC_ALARM_HOURS_REG 0x28
#define OMAP_RTC_ALARM_DAYS_REG 0x2c
#define OMAP_RTC_ALARM_MONTHS_REG 0x30
#define OMAP_RTC_ALARM_YEARS_REG 0x34
#define OMAP_RTC_CTRL_REG 0x40
#define OMAP_RTC_STATUS_REG 0x44
#define OMAP_RTC_INTERRUPTS_REG 0x48
#define OMAP_RTC_COMP_LSB_REG 0x4c
#define OMAP_RTC_COMP_MSB_REG 0x50
#define OMAP_RTC_OSC_REG 0x54
/* OMAP_RTC_CTRL_REG bit fields: */
#define OMAP_RTC_CTRL_SPLIT (1<<7)
#define OMAP_RTC_CTRL_DISABLE (1<<6)
#define OMAP_RTC_CTRL_SET_32_COUNTER (1<<5)
#define OMAP_RTC_CTRL_TEST (1<<4)
#define OMAP_RTC_CTRL_MODE_12_24 (1<<3)
#define OMAP_RTC_CTRL_AUTO_COMP (1<<2)
#define OMAP_RTC_CTRL_ROUND_30S (1<<1)
#define OMAP_RTC_CTRL_STOP (1<<0)
/* OMAP_RTC_STATUS_REG bit fields: */
#define OMAP_RTC_STATUS_POWER_UP (1<<7)
#define OMAP_RTC_STATUS_ALARM (1<<6)
#define OMAP_RTC_STATUS_1D_EVENT (1<<5)
#define OMAP_RTC_STATUS_1H_EVENT (1<<4)
#define OMAP_RTC_STATUS_1M_EVENT (1<<3)
#define OMAP_RTC_STATUS_1S_EVENT (1<<2)
#define OMAP_RTC_STATUS_RUN (1<<1)
#define OMAP_RTC_STATUS_BUSY (1<<0)
/* OMAP_RTC_INTERRUPTS_REG bit fields: */
#define OMAP_RTC_INTERRUPTS_IT_ALARM (1<<3)
#define OMAP_RTC_INTERRUPTS_IT_TIMER (1<<2)
static void __iomem *rtc_base;
#define rtc_read(addr) __raw_readb(rtc_base + (addr))
#define rtc_write(val, addr) __raw_writeb(val, rtc_base + (addr))
/* we rely on the rtc framework to handle locking (rtc->ops_lock),
* so the only other requirement is that register accesses which
* require BUSY to be clear are made with IRQs locally disabled
*/
static void rtc_wait_not_busy(void)
{
int count = 0;
u8 status;
/* BUSY may stay active for 1/32768 second (~30 usec) */
for (count = 0; count < 50; count++) {
status = rtc_read(OMAP_RTC_STATUS_REG);
if ((status & (u8)OMAP_RTC_STATUS_BUSY) == 0)
break;
udelay(1);
}
/* now we have ~15 usec to read/write various registers */
}
static irqreturn_t rtc_irq(int irq, void *rtc)
{
unsigned long events = 0;
u8 irq_data;
irq_data = rtc_read(OMAP_RTC_STATUS_REG);
/* alarm irq? */
if (irq_data & OMAP_RTC_STATUS_ALARM) {
rtc_write(OMAP_RTC_STATUS_ALARM, OMAP_RTC_STATUS_REG);
events |= RTC_IRQF | RTC_AF;
}
/* 1/sec periodic/update irq? */
if (irq_data & OMAP_RTC_STATUS_1S_EVENT)
events |= RTC_IRQF | RTC_UF;
rtc_update_irq(rtc, 1, events);
return IRQ_HANDLED;
}
static int omap_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
u8 reg;
local_irq_disable();
rtc_wait_not_busy();
reg = rtc_read(OMAP_RTC_INTERRUPTS_REG);
if (enabled)
reg |= OMAP_RTC_INTERRUPTS_IT_ALARM;
else
reg &= ~OMAP_RTC_INTERRUPTS_IT_ALARM;
rtc_wait_not_busy();
rtc_write(reg, OMAP_RTC_INTERRUPTS_REG);
local_irq_enable();
return 0;
}
/* this hardware doesn't support "don't care" alarm fields */
static int tm2bcd(struct rtc_time *tm)
{
if (rtc_valid_tm(tm) != 0)
return -EINVAL;
tm->tm_sec = bin2bcd(tm->tm_sec);
tm->tm_min = bin2bcd(tm->tm_min);
tm->tm_hour = bin2bcd(tm->tm_hour);
tm->tm_mday = bin2bcd(tm->tm_mday);
tm->tm_mon = bin2bcd(tm->tm_mon + 1);
/* epoch == 1900 */
if (tm->tm_year < 100 || tm->tm_year > 199)
return -EINVAL;
tm->tm_year = bin2bcd(tm->tm_year - 100);
return 0;
}
static void bcd2tm(struct rtc_time *tm)
{
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) - 1;
/* epoch == 1900 */
tm->tm_year = bcd2bin(tm->tm_year) + 100;
}
static int omap_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
/* we don't report wday/yday/isdst ... */
local_irq_disable();
rtc_wait_not_busy();
tm->tm_sec = rtc_read(OMAP_RTC_SECONDS_REG);
tm->tm_min = rtc_read(OMAP_RTC_MINUTES_REG);
tm->tm_hour = rtc_read(OMAP_RTC_HOURS_REG);
tm->tm_mday = rtc_read(OMAP_RTC_DAYS_REG);
tm->tm_mon = rtc_read(OMAP_RTC_MONTHS_REG);
tm->tm_year = rtc_read(OMAP_RTC_YEARS_REG);
local_irq_enable();
bcd2tm(tm);
return 0;
}
static int omap_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
if (tm2bcd(tm) < 0)
return -EINVAL;
local_irq_disable();
rtc_wait_not_busy();
rtc_write(tm->tm_year, OMAP_RTC_YEARS_REG);
rtc_write(tm->tm_mon, OMAP_RTC_MONTHS_REG);
rtc_write(tm->tm_mday, OMAP_RTC_DAYS_REG);
rtc_write(tm->tm_hour, OMAP_RTC_HOURS_REG);
rtc_write(tm->tm_min, OMAP_RTC_MINUTES_REG);
rtc_write(tm->tm_sec, OMAP_RTC_SECONDS_REG);
local_irq_enable();
return 0;
}
static int omap_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
local_irq_disable();
rtc_wait_not_busy();
alm->time.tm_sec = rtc_read(OMAP_RTC_ALARM_SECONDS_REG);
alm->time.tm_min = rtc_read(OMAP_RTC_ALARM_MINUTES_REG);
alm->time.tm_hour = rtc_read(OMAP_RTC_ALARM_HOURS_REG);
alm->time.tm_mday = rtc_read(OMAP_RTC_ALARM_DAYS_REG);
alm->time.tm_mon = rtc_read(OMAP_RTC_ALARM_MONTHS_REG);
alm->time.tm_year = rtc_read(OMAP_RTC_ALARM_YEARS_REG);
local_irq_enable();
bcd2tm(&alm->time);
alm->enabled = !!(rtc_read(OMAP_RTC_INTERRUPTS_REG)
& OMAP_RTC_INTERRUPTS_IT_ALARM);
return 0;
}
static int omap_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
u8 reg;
if (tm2bcd(&alm->time) < 0)
return -EINVAL;
local_irq_disable();
rtc_wait_not_busy();
rtc_write(alm->time.tm_year, OMAP_RTC_ALARM_YEARS_REG);
rtc_write(alm->time.tm_mon, OMAP_RTC_ALARM_MONTHS_REG);
rtc_write(alm->time.tm_mday, OMAP_RTC_ALARM_DAYS_REG);
rtc_write(alm->time.tm_hour, OMAP_RTC_ALARM_HOURS_REG);
rtc_write(alm->time.tm_min, OMAP_RTC_ALARM_MINUTES_REG);
rtc_write(alm->time.tm_sec, OMAP_RTC_ALARM_SECONDS_REG);
reg = rtc_read(OMAP_RTC_INTERRUPTS_REG);
if (alm->enabled)
reg |= OMAP_RTC_INTERRUPTS_IT_ALARM;
else
reg &= ~OMAP_RTC_INTERRUPTS_IT_ALARM;
rtc_write(reg, OMAP_RTC_INTERRUPTS_REG);
local_irq_enable();
return 0;
}
static struct rtc_class_ops omap_rtc_ops = {
.read_time = omap_rtc_read_time,
.set_time = omap_rtc_set_time,
.read_alarm = omap_rtc_read_alarm,
.set_alarm = omap_rtc_set_alarm,
.alarm_irq_enable = omap_rtc_alarm_irq_enable,
};
static int omap_rtc_alarm;
static int omap_rtc_timer;
static int __init omap_rtc_probe(struct platform_device *pdev)
{
struct resource *res, *mem;
struct rtc_device *rtc;
u8 reg, new_ctrl;
omap_rtc_timer = platform_get_irq(pdev, 0);
if (omap_rtc_timer <= 0) {
pr_debug("%s: no update irq?\n", pdev->name);
return -ENOENT;
}
omap_rtc_alarm = platform_get_irq(pdev, 1);
if (omap_rtc_alarm <= 0) {
pr_debug("%s: no alarm irq?\n", pdev->name);
return -ENOENT;
}
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res) {
pr_debug("%s: RTC resource data missing\n", pdev->name);
return -ENOENT;
}
mem = request_mem_region(res->start, resource_size(res), pdev->name);
if (!mem) {
pr_debug("%s: RTC registers at %08x are not free\n",
pdev->name, res->start);
return -EBUSY;
}
rtc_base = ioremap(res->start, resource_size(res));
if (!rtc_base) {
pr_debug("%s: RTC registers can't be mapped\n", pdev->name);
goto fail;
}
rtc = rtc_device_register(pdev->name, &pdev->dev,
&omap_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc)) {
pr_debug("%s: can't register RTC device, err %ld\n",
pdev->name, PTR_ERR(rtc));
goto fail0;
}
platform_set_drvdata(pdev, rtc);
dev_set_drvdata(&rtc->dev, mem);
/* clear pending irqs, and set 1/second periodic,
* which we'll use instead of update irqs
*/
rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
/* clear old status */
reg = rtc_read(OMAP_RTC_STATUS_REG);
if (reg & (u8) OMAP_RTC_STATUS_POWER_UP) {
pr_info("%s: RTC power up reset detected\n",
pdev->name);
rtc_write(OMAP_RTC_STATUS_POWER_UP, OMAP_RTC_STATUS_REG);
}
if (reg & (u8) OMAP_RTC_STATUS_ALARM)
rtc_write(OMAP_RTC_STATUS_ALARM, OMAP_RTC_STATUS_REG);
/* handle periodic and alarm irqs */
if (request_irq(omap_rtc_timer, rtc_irq, IRQF_DISABLED,
dev_name(&rtc->dev), rtc)) {
pr_debug("%s: RTC timer interrupt IRQ%d already claimed\n",
pdev->name, omap_rtc_timer);
goto fail1;
}
if ((omap_rtc_timer != omap_rtc_alarm) &&
(request_irq(omap_rtc_alarm, rtc_irq, IRQF_DISABLED,
dev_name(&rtc->dev), rtc))) {
pr_debug("%s: RTC alarm interrupt IRQ%d already claimed\n",
pdev->name, omap_rtc_alarm);
goto fail2;
}
/* On boards with split power, RTC_ON_NOFF won't reset the RTC */
reg = rtc_read(OMAP_RTC_CTRL_REG);
if (reg & (u8) OMAP_RTC_CTRL_STOP)
pr_info("%s: already running\n", pdev->name);
/* force to 24 hour mode */
new_ctrl = reg & ~(OMAP_RTC_CTRL_SPLIT|OMAP_RTC_CTRL_AUTO_COMP);
new_ctrl |= OMAP_RTC_CTRL_STOP;
/* BOARD-SPECIFIC CUSTOMIZATION CAN GO HERE:
*
* - Device wake-up capability setting should come through chip
* init logic. OMAP1 boards should initialize the "wakeup capable"
* flag in the platform device if the board is wired right for
* being woken up by RTC alarm. For OMAP-L138, this capability
* is built into the SoC by the "Deep Sleep" capability.
*
* - Boards wired so RTC_ON_nOFF is used as the reset signal,
* rather than nPWRON_RESET, should forcibly enable split
* power mode. (Some chip errata report that RTC_CTRL_SPLIT
* is write-only, and always reads as zero...)
*/
if (new_ctrl & (u8) OMAP_RTC_CTRL_SPLIT)
pr_info("%s: split power mode\n", pdev->name);
if (reg != new_ctrl)
rtc_write(new_ctrl, OMAP_RTC_CTRL_REG);
return 0;
fail2:
free_irq(omap_rtc_timer, rtc);
fail1:
rtc_device_unregister(rtc);
fail0:
iounmap(rtc_base);
fail:
release_mem_region(mem->start, resource_size(mem));
return -EIO;
}
static int __exit omap_rtc_remove(struct platform_device *pdev)
{
struct rtc_device *rtc = platform_get_drvdata(pdev);
struct resource *mem = dev_get_drvdata(&rtc->dev);
device_init_wakeup(&pdev->dev, 0);
/* leave rtc running, but disable irqs */
rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
free_irq(omap_rtc_timer, rtc);
if (omap_rtc_timer != omap_rtc_alarm)
free_irq(omap_rtc_alarm, rtc);
rtc_device_unregister(rtc);
iounmap(rtc_base);
release_mem_region(mem->start, resource_size(mem));
return 0;
}
#ifdef CONFIG_PM
static u8 irqstat;
static int omap_rtc_suspend(struct platform_device *pdev, pm_message_t state)
{
irqstat = rtc_read(OMAP_RTC_INTERRUPTS_REG);
/* FIXME the RTC alarm is not currently acting as a wakeup event
* source, and in fact this enable() call is just saving a flag
* that's never used...
*/
if (device_may_wakeup(&pdev->dev))
enable_irq_wake(omap_rtc_alarm);
else
rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
return 0;
}
static int omap_rtc_resume(struct platform_device *pdev)
{
if (device_may_wakeup(&pdev->dev))
disable_irq_wake(omap_rtc_alarm);
else
rtc_write(irqstat, OMAP_RTC_INTERRUPTS_REG);
return 0;
}
#else
#define omap_rtc_suspend NULL
#define omap_rtc_resume NULL
#endif
static void omap_rtc_shutdown(struct platform_device *pdev)
{
rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
}
MODULE_ALIAS("platform:omap_rtc");
static struct platform_driver omap_rtc_driver = {
.remove = __exit_p(omap_rtc_remove),
.suspend = omap_rtc_suspend,
.resume = omap_rtc_resume,
.shutdown = omap_rtc_shutdown,
.driver = {
.name = "omap_rtc",
.owner = THIS_MODULE,
},
};
static int __init rtc_init(void)
{
return platform_driver_probe(&omap_rtc_driver, omap_rtc_probe);
}
module_init(rtc_init);
static void __exit rtc_exit(void)
{
platform_driver_unregister(&omap_rtc_driver);
}
module_exit(rtc_exit);
MODULE_AUTHOR("George G. Davis (and others)");
MODULE_LICENSE("GPL");