| /* |
| * rtc-st-lpc.c - ST's LPC RTC, powered by the Low Power Timer |
| * |
| * Copyright (C) 2014 STMicroelectronics Limited |
| * |
| * Author: David Paris <david.paris@st.com> for STMicroelectronics |
| * Lee Jones <lee.jones@linaro.org> for STMicroelectronics |
| * |
| * Based on the original driver written by Stuart Menefy. |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public Licence |
| * as published by the Free Software Foundation; either version |
| * 2 of the Licence, or (at your option) any later version. |
| */ |
| |
| #include <linux/clk.h> |
| #include <linux/delay.h> |
| #include <linux/init.h> |
| #include <linux/io.h> |
| #include <linux/irq.h> |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/of.h> |
| #include <linux/of_irq.h> |
| #include <linux/platform_device.h> |
| #include <linux/rtc.h> |
| |
| #include <dt-bindings/mfd/st-lpc.h> |
| |
| /* Low Power Timer */ |
| #define LPC_LPT_LSB_OFF 0x400 |
| #define LPC_LPT_MSB_OFF 0x404 |
| #define LPC_LPT_START_OFF 0x408 |
| |
| /* Low Power Alarm */ |
| #define LPC_LPA_LSB_OFF 0x410 |
| #define LPC_LPA_MSB_OFF 0x414 |
| #define LPC_LPA_START_OFF 0x418 |
| |
| /* LPC as WDT */ |
| #define LPC_WDT_OFF 0x510 |
| #define LPC_WDT_FLAG_OFF 0x514 |
| |
| struct st_rtc { |
| struct rtc_device *rtc_dev; |
| struct rtc_wkalrm alarm; |
| struct resource *res; |
| struct clk *clk; |
| unsigned long clkrate; |
| void __iomem *ioaddr; |
| bool irq_enabled:1; |
| spinlock_t lock; |
| short irq; |
| }; |
| |
| static void st_rtc_set_hw_alarm(struct st_rtc *rtc, |
| unsigned long msb, unsigned long lsb) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&rtc->lock, flags); |
| |
| writel_relaxed(1, rtc->ioaddr + LPC_WDT_OFF); |
| |
| writel_relaxed(msb, rtc->ioaddr + LPC_LPA_MSB_OFF); |
| writel_relaxed(lsb, rtc->ioaddr + LPC_LPA_LSB_OFF); |
| writel_relaxed(1, rtc->ioaddr + LPC_LPA_START_OFF); |
| |
| writel_relaxed(0, rtc->ioaddr + LPC_WDT_OFF); |
| |
| spin_unlock_irqrestore(&rtc->lock, flags); |
| } |
| |
| static irqreturn_t st_rtc_handler(int this_irq, void *data) |
| { |
| struct st_rtc *rtc = (struct st_rtc *)data; |
| |
| rtc_update_irq(rtc->rtc_dev, 1, RTC_AF); |
| |
| return IRQ_HANDLED; |
| } |
| |
| static int st_rtc_read_time(struct device *dev, struct rtc_time *tm) |
| { |
| struct st_rtc *rtc = dev_get_drvdata(dev); |
| unsigned long lpt_lsb, lpt_msb; |
| unsigned long long lpt; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&rtc->lock, flags); |
| |
| do { |
| lpt_msb = readl_relaxed(rtc->ioaddr + LPC_LPT_MSB_OFF); |
| lpt_lsb = readl_relaxed(rtc->ioaddr + LPC_LPT_LSB_OFF); |
| } while (readl_relaxed(rtc->ioaddr + LPC_LPT_MSB_OFF) != lpt_msb); |
| |
| spin_unlock_irqrestore(&rtc->lock, flags); |
| |
| lpt = ((unsigned long long)lpt_msb << 32) | lpt_lsb; |
| do_div(lpt, rtc->clkrate); |
| rtc_time_to_tm(lpt, tm); |
| |
| return 0; |
| } |
| |
| static int st_rtc_set_time(struct device *dev, struct rtc_time *tm) |
| { |
| struct st_rtc *rtc = dev_get_drvdata(dev); |
| unsigned long long lpt; |
| unsigned long secs, flags; |
| int ret; |
| |
| ret = rtc_tm_to_time(tm, &secs); |
| if (ret) |
| return ret; |
| |
| lpt = (unsigned long long)secs * rtc->clkrate; |
| |
| spin_lock_irqsave(&rtc->lock, flags); |
| |
| writel_relaxed(lpt >> 32, rtc->ioaddr + LPC_LPT_MSB_OFF); |
| writel_relaxed(lpt, rtc->ioaddr + LPC_LPT_LSB_OFF); |
| writel_relaxed(1, rtc->ioaddr + LPC_LPT_START_OFF); |
| |
| spin_unlock_irqrestore(&rtc->lock, flags); |
| |
| return 0; |
| } |
| |
| static int st_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm) |
| { |
| struct st_rtc *rtc = dev_get_drvdata(dev); |
| unsigned long flags; |
| |
| spin_lock_irqsave(&rtc->lock, flags); |
| |
| memcpy(wkalrm, &rtc->alarm, sizeof(struct rtc_wkalrm)); |
| |
| spin_unlock_irqrestore(&rtc->lock, flags); |
| |
| return 0; |
| } |
| |
| static int st_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) |
| { |
| struct st_rtc *rtc = dev_get_drvdata(dev); |
| |
| if (enabled && !rtc->irq_enabled) { |
| enable_irq(rtc->irq); |
| rtc->irq_enabled = true; |
| } else if (!enabled && rtc->irq_enabled) { |
| disable_irq(rtc->irq); |
| rtc->irq_enabled = false; |
| } |
| |
| return 0; |
| } |
| |
| static int st_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *t) |
| { |
| struct st_rtc *rtc = dev_get_drvdata(dev); |
| struct rtc_time now; |
| unsigned long now_secs; |
| unsigned long alarm_secs; |
| unsigned long long lpa; |
| |
| st_rtc_read_time(dev, &now); |
| rtc_tm_to_time(&now, &now_secs); |
| rtc_tm_to_time(&t->time, &alarm_secs); |
| |
| /* Invalid alarm time */ |
| if (now_secs > alarm_secs) |
| return -EINVAL; |
| |
| memcpy(&rtc->alarm, t, sizeof(struct rtc_wkalrm)); |
| |
| /* Now many secs to fire */ |
| alarm_secs -= now_secs; |
| lpa = (unsigned long long)alarm_secs * rtc->clkrate; |
| |
| st_rtc_set_hw_alarm(rtc, lpa >> 32, lpa); |
| st_rtc_alarm_irq_enable(dev, t->enabled); |
| |
| return 0; |
| } |
| |
| static struct rtc_class_ops st_rtc_ops = { |
| .read_time = st_rtc_read_time, |
| .set_time = st_rtc_set_time, |
| .read_alarm = st_rtc_read_alarm, |
| .set_alarm = st_rtc_set_alarm, |
| .alarm_irq_enable = st_rtc_alarm_irq_enable, |
| }; |
| |
| static int st_rtc_probe(struct platform_device *pdev) |
| { |
| struct device_node *np = pdev->dev.of_node; |
| struct st_rtc *rtc; |
| struct resource *res; |
| struct rtc_time tm_check; |
| uint32_t mode; |
| int ret = 0; |
| |
| ret = of_property_read_u32(np, "st,lpc-mode", &mode); |
| if (ret) { |
| dev_err(&pdev->dev, "An LPC mode must be provided\n"); |
| return -EINVAL; |
| } |
| |
| /* LPC can either run in RTC or WDT mode */ |
| if (mode != ST_LPC_MODE_RTC) |
| return -ENODEV; |
| |
| rtc = devm_kzalloc(&pdev->dev, sizeof(struct st_rtc), GFP_KERNEL); |
| if (!rtc) |
| return -ENOMEM; |
| |
| spin_lock_init(&rtc->lock); |
| |
| res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| rtc->ioaddr = devm_ioremap_resource(&pdev->dev, res); |
| if (IS_ERR(rtc->ioaddr)) |
| return PTR_ERR(rtc->ioaddr); |
| |
| rtc->irq = irq_of_parse_and_map(np, 0); |
| if (!rtc->irq) { |
| dev_err(&pdev->dev, "IRQ missing or invalid\n"); |
| return -EINVAL; |
| } |
| |
| ret = devm_request_irq(&pdev->dev, rtc->irq, st_rtc_handler, 0, |
| pdev->name, rtc); |
| if (ret) { |
| dev_err(&pdev->dev, "Failed to request irq %i\n", rtc->irq); |
| return ret; |
| } |
| |
| enable_irq_wake(rtc->irq); |
| disable_irq(rtc->irq); |
| |
| rtc->clk = clk_get(&pdev->dev, NULL); |
| if (IS_ERR(rtc->clk)) { |
| dev_err(&pdev->dev, "Unable to request clock\n"); |
| return PTR_ERR(rtc->clk); |
| } |
| |
| clk_prepare_enable(rtc->clk); |
| |
| rtc->clkrate = clk_get_rate(rtc->clk); |
| if (!rtc->clkrate) { |
| dev_err(&pdev->dev, "Unable to fetch clock rate\n"); |
| return -EINVAL; |
| } |
| |
| device_set_wakeup_capable(&pdev->dev, 1); |
| |
| platform_set_drvdata(pdev, rtc); |
| |
| /* |
| * The RTC-LPC is able to manage date.year > 2038 |
| * but currently the kernel can not manage this date! |
| * If the RTC-LPC has a date.year > 2038 then |
| * it's set to the epoch "Jan 1st 2000" |
| */ |
| st_rtc_read_time(&pdev->dev, &tm_check); |
| |
| if (tm_check.tm_year >= (2038 - 1900)) { |
| memset(&tm_check, 0, sizeof(tm_check)); |
| tm_check.tm_year = 100; |
| tm_check.tm_mday = 1; |
| st_rtc_set_time(&pdev->dev, &tm_check); |
| } |
| |
| rtc->rtc_dev = rtc_device_register("st-lpc-rtc", &pdev->dev, |
| &st_rtc_ops, THIS_MODULE); |
| if (IS_ERR(rtc->rtc_dev)) { |
| clk_disable_unprepare(rtc->clk); |
| return PTR_ERR(rtc->rtc_dev); |
| } |
| |
| return 0; |
| } |
| |
| static int st_rtc_remove(struct platform_device *pdev) |
| { |
| struct st_rtc *rtc = platform_get_drvdata(pdev); |
| |
| if (likely(rtc->rtc_dev)) |
| rtc_device_unregister(rtc->rtc_dev); |
| |
| return 0; |
| } |
| |
| #ifdef CONFIG_PM_SLEEP |
| static int st_rtc_suspend(struct device *dev) |
| { |
| struct st_rtc *rtc = dev_get_drvdata(dev); |
| |
| if (device_may_wakeup(dev)) |
| return 0; |
| |
| writel_relaxed(1, rtc->ioaddr + LPC_WDT_OFF); |
| writel_relaxed(0, rtc->ioaddr + LPC_LPA_START_OFF); |
| writel_relaxed(0, rtc->ioaddr + LPC_WDT_OFF); |
| |
| return 0; |
| } |
| |
| static int st_rtc_resume(struct device *dev) |
| { |
| struct st_rtc *rtc = dev_get_drvdata(dev); |
| |
| rtc_alarm_irq_enable(rtc->rtc_dev, 0); |
| |
| /* |
| * clean 'rtc->alarm' to allow a new |
| * .set_alarm to the upper RTC layer |
| */ |
| memset(&rtc->alarm, 0, sizeof(struct rtc_wkalrm)); |
| |
| writel_relaxed(0, rtc->ioaddr + LPC_LPA_MSB_OFF); |
| writel_relaxed(0, rtc->ioaddr + LPC_LPA_LSB_OFF); |
| writel_relaxed(1, rtc->ioaddr + LPC_WDT_OFF); |
| writel_relaxed(1, rtc->ioaddr + LPC_LPA_START_OFF); |
| writel_relaxed(0, rtc->ioaddr + LPC_WDT_OFF); |
| |
| return 0; |
| } |
| #endif |
| |
| static SIMPLE_DEV_PM_OPS(st_rtc_pm_ops, st_rtc_suspend, st_rtc_resume); |
| |
| static const struct of_device_id st_rtc_match[] = { |
| { .compatible = "st,stih407-lpc" }, |
| {} |
| }; |
| MODULE_DEVICE_TABLE(of, st_rtc_match); |
| |
| static struct platform_driver st_rtc_platform_driver = { |
| .driver = { |
| .name = "st-lpc-rtc", |
| .pm = &st_rtc_pm_ops, |
| .of_match_table = st_rtc_match, |
| }, |
| .probe = st_rtc_probe, |
| .remove = st_rtc_remove, |
| }; |
| |
| module_platform_driver(st_rtc_platform_driver); |
| |
| MODULE_DESCRIPTION("STMicroelectronics LPC RTC driver"); |
| MODULE_AUTHOR("David Paris <david.paris@st.com>"); |
| MODULE_LICENSE("GPL"); |