// SPDX-License-Identifier: GPL-2.0-or-later /* * 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 * * Modifications from: * CIH * Nicolas Pitre * Andrew Christian * * Converted to the RTC subsystem and Driver Model * by Richard Purdie */ #include #include #include #include #include #include #include #include #include #include #include #include #include #define RTSR_HZE BIT(3) /* HZ interrupt enable */ #define RTSR_ALE BIT(2) /* RTC alarm interrupt enable */ #define RTSR_HZ BIT(1) /* HZ rising-edge detected */ #define RTSR_AL BIT(0) /* RTC alarm detected */ #include "rtc-sa1100.h" #define RTC_DEF_DIVIDER (32768 - 1) #define RTC_DEF_TRIM 0 #define RTC_FREQ 1024 static irqreturn_t sa1100_rtc_interrupt(int irq, void *dev_id) { struct sa1100_rtc *info = dev_get_drvdata(dev_id); struct rtc_device *rtc = info->rtc; unsigned int rtsr; unsigned long events = 0; spin_lock(&info->lock); rtsr = readl_relaxed(info->rtsr); /* clear interrupt sources */ writel_relaxed(0, info->rtsr); /* Fix for a nasty initialization problem the in SA11xx RTSR register. * See also the comments in sa1100_rtc_probe(). */ if (rtsr & (RTSR_ALE | RTSR_HZE)) { /* This is the original code, before there was the if test * above. This code does not clear interrupts that were not * enabled. */ writel_relaxed((RTSR_AL | RTSR_HZ) & (rtsr >> 2), info->rtsr); } else { /* For some reason, it is possible to enter this routine * without interruptions enabled, it has been tested with * several units (Bug in SA11xx chip?). * * This situation leads to an infinite "loop" of interrupt * routine calling and as a result the processor seems to * lock on its first call to open(). */ writel_relaxed(RTSR_AL | RTSR_HZ, info->rtsr); } /* clear alarm interrupt if it has occurred */ if (rtsr & RTSR_AL) rtsr &= ~RTSR_ALE; writel_relaxed(rtsr & (RTSR_ALE | RTSR_HZE), info->rtsr); /* 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, 1, events); spin_unlock(&info->lock); return IRQ_HANDLED; } static int sa1100_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) { u32 rtsr; struct sa1100_rtc *info = dev_get_drvdata(dev); spin_lock_irq(&info->lock); rtsr = readl_relaxed(info->rtsr); if (enabled) rtsr |= RTSR_ALE; else rtsr &= ~RTSR_ALE; writel_relaxed(rtsr, info->rtsr); spin_unlock_irq(&info->lock); return 0; } static int sa1100_rtc_read_time(struct device *dev, struct rtc_time *tm) { struct sa1100_rtc *info = dev_get_drvdata(dev); rtc_time_to_tm(readl_relaxed(info->rcnr), tm); return 0; } static int sa1100_rtc_set_time(struct device *dev, struct rtc_time *tm) { struct sa1100_rtc *info = dev_get_drvdata(dev); unsigned long time; int ret; ret = rtc_tm_to_time(tm, &time); if (ret == 0) writel_relaxed(time, info->rcnr); return ret; } static int sa1100_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) { u32 rtsr; struct sa1100_rtc *info = dev_get_drvdata(dev); rtsr = readl_relaxed(info->rtsr); alrm->enabled = (rtsr & RTSR_ALE) ? 1 : 0; alrm->pending = (rtsr & RTSR_AL) ? 1 : 0; return 0; } static int sa1100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) { struct sa1100_rtc *info = dev_get_drvdata(dev); unsigned long time; int ret; spin_lock_irq(&info->lock); ret = rtc_tm_to_time(&alrm->time, &time); if (ret != 0) goto out; writel_relaxed(readl_relaxed(info->rtsr) & (RTSR_HZE | RTSR_ALE | RTSR_AL), info->rtsr); writel_relaxed(time, info->rtar); if (alrm->enabled) writel_relaxed(readl_relaxed(info->rtsr) | RTSR_ALE, info->rtsr); else writel_relaxed(readl_relaxed(info->rtsr) & ~RTSR_ALE, info->rtsr); out: spin_unlock_irq(&info->lock); return ret; } static int sa1100_rtc_proc(struct device *dev, struct seq_file *seq) { struct sa1100_rtc *info = dev_get_drvdata(dev); seq_printf(seq, "trim/divider\t\t: 0x%08x\n", readl_relaxed(info->rttr)); seq_printf(seq, "RTSR\t\t\t: 0x%08x\n", readl_relaxed(info->rtsr)); return 0; } static const struct rtc_class_ops sa1100_rtc_ops = { .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, .alarm_irq_enable = sa1100_rtc_alarm_irq_enable, }; int sa1100_rtc_init(struct platform_device *pdev, struct sa1100_rtc *info) { int ret; spin_lock_init(&info->lock); info->clk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(info->clk)) { dev_err(&pdev->dev, "failed to find rtc clock source\n"); return PTR_ERR(info->clk); } ret = clk_prepare_enable(info->clk); if (ret) return ret; /* * 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 (readl_relaxed(info->rttr) == 0) { writel_relaxed(RTC_DEF_DIVIDER + (RTC_DEF_TRIM << 16), info->rttr); dev_warn(&pdev->dev, "warning: " "initializing default clock divider/trim value\n"); /* The current RTC value probably doesn't make sense either */ writel_relaxed(0, info->rcnr); } info->rtc->ops = &sa1100_rtc_ops; info->rtc->max_user_freq = RTC_FREQ; info->rtc->range_max = U32_MAX; ret = rtc_register_device(info->rtc); if (ret) { clk_disable_unprepare(info->clk); return ret; } /* Fix for a nasty initialization problem the in SA11xx RTSR register. * See also the comments in sa1100_rtc_interrupt(). * * Sometimes bit 1 of the RTSR (RTSR_HZ) will wake up 1, which means an * interrupt pending, even though interrupts were never enabled. * In this case, this bit it must be reset before enabling * interruptions to avoid a nonexistent interrupt to occur. * * In principle, the same problem would apply to bit 0, although it has * never been observed to happen. * * This issue is addressed both here and in sa1100_rtc_interrupt(). * If the issue is not addressed here, in the times when the processor * wakes up with the bit set there will be one spurious interrupt. * * The issue is also dealt with in sa1100_rtc_interrupt() to be on the * safe side, once the condition that lead to this strange * initialization is unknown and could in principle happen during * normal processing. * * Notice that clearing bit 1 and 0 is accomplished by writting ONES to * the corresponding bits in RTSR. */ writel_relaxed(RTSR_AL | RTSR_HZ, info->rtsr); return 0; } EXPORT_SYMBOL_GPL(sa1100_rtc_init); static int sa1100_rtc_probe(struct platform_device *pdev) { struct sa1100_rtc *info; void __iomem *base; int irq_1hz, irq_alarm; int ret; irq_1hz = platform_get_irq_byname(pdev, "rtc 1Hz"); irq_alarm = platform_get_irq_byname(pdev, "rtc alarm"); if (irq_1hz < 0 || irq_alarm < 0) return -ENODEV; info = devm_kzalloc(&pdev->dev, sizeof(struct sa1100_rtc), GFP_KERNEL); if (!info) return -ENOMEM; info->irq_1hz = irq_1hz; info->irq_alarm = irq_alarm; info->rtc = devm_rtc_allocate_device(&pdev->dev); if (IS_ERR(info->rtc)) return PTR_ERR(info->rtc); ret = devm_request_irq(&pdev->dev, irq_1hz, sa1100_rtc_interrupt, 0, "rtc 1Hz", &pdev->dev); if (ret) { dev_err(&pdev->dev, "IRQ %d already in use.\n", irq_1hz); return ret; } ret = devm_request_irq(&pdev->dev, irq_alarm, sa1100_rtc_interrupt, 0, "rtc Alrm", &pdev->dev); if (ret) { dev_err(&pdev->dev, "IRQ %d already in use.\n", irq_alarm); return ret; } base = devm_platform_ioremap_resource(pdev, 0); if (IS_ERR(base)) return PTR_ERR(base); if (IS_ENABLED(CONFIG_ARCH_SA1100) || of_device_is_compatible(pdev->dev.of_node, "mrvl,sa1100-rtc")) { info->rcnr = base + 0x04; info->rtsr = base + 0x10; info->rtar = base + 0x00; info->rttr = base + 0x08; } else { info->rcnr = base + 0x0; info->rtsr = base + 0x8; info->rtar = base + 0x4; info->rttr = base + 0xc; } platform_set_drvdata(pdev, info); device_init_wakeup(&pdev->dev, 1); return sa1100_rtc_init(pdev, info); } static int sa1100_rtc_remove(struct platform_device *pdev) { struct sa1100_rtc *info = platform_get_drvdata(pdev); if (info) { spin_lock_irq(&info->lock); writel_relaxed(0, info->rtsr); spin_unlock_irq(&info->lock); clk_disable_unprepare(info->clk); } return 0; } #ifdef CONFIG_PM_SLEEP static int sa1100_rtc_suspend(struct device *dev) { struct sa1100_rtc *info = dev_get_drvdata(dev); if (device_may_wakeup(dev)) enable_irq_wake(info->irq_alarm); return 0; } static int sa1100_rtc_resume(struct device *dev) { struct sa1100_rtc *info = dev_get_drvdata(dev); if (device_may_wakeup(dev)) disable_irq_wake(info->irq_alarm); return 0; } #endif static SIMPLE_DEV_PM_OPS(sa1100_rtc_pm_ops, sa1100_rtc_suspend, sa1100_rtc_resume); #ifdef CONFIG_OF static const struct of_device_id sa1100_rtc_dt_ids[] = { { .compatible = "mrvl,sa1100-rtc", }, { .compatible = "mrvl,mmp-rtc", }, {} }; MODULE_DEVICE_TABLE(of, sa1100_rtc_dt_ids); #endif static struct platform_driver sa1100_rtc_driver = { .probe = sa1100_rtc_probe, .remove = sa1100_rtc_remove, .driver = { .name = "sa1100-rtc", .pm = &sa1100_rtc_pm_ops, .of_match_table = of_match_ptr(sa1100_rtc_dt_ids), }, }; module_platform_driver(sa1100_rtc_driver); MODULE_AUTHOR("Richard Purdie "); MODULE_DESCRIPTION("SA11x0/PXA2xx Realtime Clock Driver (RTC)"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:sa1100-rtc");