diff options
Diffstat (limited to 'drivers/rtc/rtc-at32ap700x.c')
| -rw-r--r-- | drivers/rtc/rtc-at32ap700x.c | 317 |
1 files changed, 317 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-at32ap700x.c b/drivers/rtc/rtc-at32ap700x.c new file mode 100644 index 000000000000..2999214ca534 --- /dev/null +++ b/drivers/rtc/rtc-at32ap700x.c @@ -0,0 +1,317 @@ +/* + * An RTC driver for the AVR32 AT32AP700x processor series. + * + * Copyright (C) 2007 Atmel Corporation + * + * 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/module.h> +#include <linux/kernel.h> +#include <linux/platform_device.h> +#include <linux/rtc.h> +#include <linux/io.h> + +/* + * This is a bare-bones RTC. It runs during most system sleep states, but has + * no battery backup and gets reset during system restart. It must be + * initialized from an external clock (network, I2C, etc) before it can be of + * much use. + * + * The alarm functionality is limited by the hardware, not supporting + * periodic interrupts. + */ + +#define RTC_CTRL 0x00 +#define RTC_CTRL_EN 0 +#define RTC_CTRL_PCLR 1 +#define RTC_CTRL_TOPEN 2 +#define RTC_CTRL_PSEL 8 + +#define RTC_VAL 0x04 + +#define RTC_TOP 0x08 + +#define RTC_IER 0x10 +#define RTC_IER_TOPI 0 + +#define RTC_IDR 0x14 +#define RTC_IDR_TOPI 0 + +#define RTC_IMR 0x18 +#define RTC_IMR_TOPI 0 + +#define RTC_ISR 0x1c +#define RTC_ISR_TOPI 0 + +#define RTC_ICR 0x20 +#define RTC_ICR_TOPI 0 + +#define RTC_BIT(name) (1 << RTC_##name) +#define RTC_BF(name, value) ((value) << RTC_##name) + +#define rtc_readl(dev, reg) \ + __raw_readl((dev)->regs + RTC_##reg) +#define rtc_writel(dev, reg, value) \ + __raw_writel((value), (dev)->regs + RTC_##reg) + +struct rtc_at32ap700x { + struct rtc_device *rtc; + void __iomem *regs; + unsigned long alarm_time; + unsigned long irq; + /* Protect against concurrent register access. */ + spinlock_t lock; +}; + +static int at32_rtc_readtime(struct device *dev, struct rtc_time *tm) +{ + struct rtc_at32ap700x *rtc = dev_get_drvdata(dev); + unsigned long now; + + now = rtc_readl(rtc, VAL); + rtc_time_to_tm(now, tm); + + return 0; +} + +static int at32_rtc_settime(struct device *dev, struct rtc_time *tm) +{ + struct rtc_at32ap700x *rtc = dev_get_drvdata(dev); + unsigned long now; + int ret; + + ret = rtc_tm_to_time(tm, &now); + if (ret == 0) + rtc_writel(rtc, VAL, now); + + return ret; +} + +static int at32_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm) +{ + struct rtc_at32ap700x *rtc = dev_get_drvdata(dev); + + rtc_time_to_tm(rtc->alarm_time, &alrm->time); + alrm->pending = rtc_readl(rtc, IMR) & RTC_BIT(IMR_TOPI) ? 1 : 0; + + return 0; +} + +static int at32_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm) +{ + struct rtc_at32ap700x *rtc = dev_get_drvdata(dev); + unsigned long rtc_unix_time; + unsigned long alarm_unix_time; + int ret; + + rtc_unix_time = rtc_readl(rtc, VAL); + + ret = rtc_tm_to_time(&alrm->time, &alarm_unix_time); + if (ret) + return ret; + + if (alarm_unix_time < rtc_unix_time) + return -EINVAL; + + spin_lock_irq(&rtc->lock); + rtc->alarm_time = alarm_unix_time; + rtc_writel(rtc, TOP, rtc->alarm_time); + if (alrm->pending) + rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL) + | RTC_BIT(CTRL_TOPEN)); + else + rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL) + & ~RTC_BIT(CTRL_TOPEN)); + spin_unlock_irq(&rtc->lock); + + return ret; +} + +static int at32_rtc_ioctl(struct device *dev, unsigned int cmd, + unsigned long arg) +{ + struct rtc_at32ap700x *rtc = dev_get_drvdata(dev); + int ret = 0; + + spin_lock_irq(&rtc->lock); + + switch (cmd) { + case RTC_AIE_ON: + if (rtc_readl(rtc, VAL) > rtc->alarm_time) { + ret = -EINVAL; + break; + } + rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL) + | RTC_BIT(CTRL_TOPEN)); + rtc_writel(rtc, ICR, RTC_BIT(ICR_TOPI)); + rtc_writel(rtc, IER, RTC_BIT(IER_TOPI)); + break; + case RTC_AIE_OFF: + rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL) + & ~RTC_BIT(CTRL_TOPEN)); + rtc_writel(rtc, IDR, RTC_BIT(IDR_TOPI)); + rtc_writel(rtc, ICR, RTC_BIT(ICR_TOPI)); + break; + default: + ret = -ENOIOCTLCMD; + break; + } + + spin_unlock_irq(&rtc->lock); + + return ret; +} + +static irqreturn_t at32_rtc_interrupt(int irq, void *dev_id) +{ + struct rtc_at32ap700x *rtc = (struct rtc_at32ap700x *)dev_id; + unsigned long isr = rtc_readl(rtc, ISR); + unsigned long events = 0; + int ret = IRQ_NONE; + + spin_lock(&rtc->lock); + + if (isr & RTC_BIT(ISR_TOPI)) { + rtc_writel(rtc, ICR, RTC_BIT(ICR_TOPI)); + rtc_writel(rtc, IDR, RTC_BIT(IDR_TOPI)); + rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL) + & ~RTC_BIT(CTRL_TOPEN)); + rtc_writel(rtc, VAL, rtc->alarm_time); + events = RTC_AF | RTC_IRQF; + rtc_update_irq(rtc->rtc, 1, events); + ret = IRQ_HANDLED; + } + + spin_unlock(&rtc->lock); + + return ret; +} + +static struct rtc_class_ops at32_rtc_ops = { + .ioctl = at32_rtc_ioctl, + .read_time = at32_rtc_readtime, + .set_time = at32_rtc_settime, + .read_alarm = at32_rtc_readalarm, + .set_alarm = at32_rtc_setalarm, +}; + +static int __init at32_rtc_probe(struct platform_device *pdev) +{ + struct resource *regs; + struct rtc_at32ap700x *rtc; + int irq = -1; + int ret; + + rtc = kzalloc(sizeof(struct rtc_at32ap700x), GFP_KERNEL); + if (!rtc) { + dev_dbg(&pdev->dev, "out of memory\n"); + return -ENOMEM; + } + + regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!regs) { + dev_dbg(&pdev->dev, "no mmio resource defined\n"); + ret = -ENXIO; + goto out; + } + + irq = platform_get_irq(pdev, 0); + if (irq < 0) { + dev_dbg(&pdev->dev, "could not get irq\n"); + ret = -ENXIO; + goto out; + } + + ret = request_irq(irq, at32_rtc_interrupt, IRQF_SHARED, "rtc", rtc); + if (ret) { + dev_dbg(&pdev->dev, "could not request irq %d\n", irq); + goto out; + } + + rtc->irq = irq; + rtc->regs = ioremap(regs->start, regs->end - regs->start + 1); + if (!rtc->regs) { + ret = -ENOMEM; + dev_dbg(&pdev->dev, "could not map I/O memory\n"); + goto out_free_irq; + } + spin_lock_init(&rtc->lock); + + /* + * Maybe init RTC: count from zero at 1 Hz, disable wrap irq. + * + * Do not reset VAL register, as it can hold an old time + * from last JTAG reset. + */ + if (!(rtc_readl(rtc, CTRL) & RTC_BIT(CTRL_EN))) { + rtc_writel(rtc, CTRL, RTC_BIT(CTRL_PCLR)); + rtc_writel(rtc, IDR, RTC_BIT(IDR_TOPI)); + rtc_writel(rtc, CTRL, RTC_BF(CTRL_PSEL, 0xe) + | RTC_BIT(CTRL_EN)); + } + + rtc->rtc = rtc_device_register(pdev->name, &pdev->dev, + &at32_rtc_ops, THIS_MODULE); + if (IS_ERR(rtc->rtc)) { + dev_dbg(&pdev->dev, "could not register rtc device\n"); + ret = PTR_ERR(rtc->rtc); + goto out_iounmap; + } + + platform_set_drvdata(pdev, rtc); + + dev_info(&pdev->dev, "Atmel RTC for AT32AP700x at %08lx irq %ld\n", + (unsigned long)rtc->regs, rtc->irq); + + return 0; + +out_iounmap: + iounmap(rtc->regs); +out_free_irq: + free_irq(irq, rtc); +out: + kfree(rtc); + return ret; +} + +static int __exit at32_rtc_remove(struct platform_device *pdev) +{ + struct rtc_at32ap700x *rtc = platform_get_drvdata(pdev); + + free_irq(rtc->irq, rtc); + iounmap(rtc->regs); + rtc_device_unregister(rtc->rtc); + kfree(rtc); + platform_set_drvdata(pdev, NULL); + + return 0; +} + +MODULE_ALIAS("at32ap700x_rtc"); + +static struct platform_driver at32_rtc_driver = { + .remove = __exit_p(at32_rtc_remove), + .driver = { + .name = "at32ap700x_rtc", + .owner = THIS_MODULE, + }, +}; + +static int __init at32_rtc_init(void) +{ + return platform_driver_probe(&at32_rtc_driver, at32_rtc_probe); +} +module_init(at32_rtc_init); + +static void __exit at32_rtc_exit(void) +{ + platform_driver_unregister(&at32_rtc_driver); +} +module_exit(at32_rtc_exit); + +MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>"); +MODULE_DESCRIPTION("Real time clock for AVR32 AT32AP700x"); +MODULE_LICENSE("GPL"); |