diff options
Diffstat (limited to 'drivers/rtc/rtc-omap.c')
| -rw-r--r-- | drivers/rtc/rtc-omap.c | 492 |
1 files changed, 492 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-omap.c b/drivers/rtc/rtc-omap.c new file mode 100644 index 00000000..0b614e32 --- /dev/null +++ b/drivers/rtc/rtc-omap.c @@ -0,0 +1,492 @@ +/* + * 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, 0, + 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, 0, + 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"); |