diff options
Diffstat (limited to 'drivers/rtc/rtc-sa1100.c')
| -rw-r--r-- | drivers/rtc/rtc-sa1100.c | 359 |
1 files changed, 359 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-sa1100.c b/drivers/rtc/rtc-sa1100.c new file mode 100644 index 000000000..1250887e4 --- /dev/null +++ b/drivers/rtc/rtc-sa1100.c @@ -0,0 +1,359 @@ +// 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 <nils@kernelconcepts.de> + * + * Modifications from: + * CIH <cih@coventive.com> + * Nicolas Pitre <nico@fluxnic.net> + * Andrew Christian <andrew.christian@hp.com> + * + * Converted to the RTC subsystem and Driver Model + * by Richard Purdie <rpurdie@rpsys.net> + */ + +#include <linux/platform_device.h> +#include <linux/module.h> +#include <linux/clk.h> +#include <linux/rtc.h> +#include <linux/init.h> +#include <linux/fs.h> +#include <linux/interrupt.h> +#include <linux/slab.h> +#include <linux/string.h> +#include <linux/of.h> +#include <linux/pm.h> +#include <linux/bitops.h> +#include <linux/io.h> + +#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_time64_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); + + writel_relaxed(rtc_tm_to_time64(tm), info->rcnr); + + return 0; +} + +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); + + spin_lock_irq(&info->lock); + writel_relaxed(readl_relaxed(info->rtsr) & + (RTSR_HZE | RTSR_ALE | RTSR_AL), info->rtsr); + writel_relaxed(rtc_tm_to_time64(&alrm->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); + spin_unlock_irq(&info->lock); + + return 0; +} + +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 = devm_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 <rpurdie@rpsys.net>"); +MODULE_DESCRIPTION("SA11x0/PXA2xx Realtime Clock Driver (RTC)"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:sa1100-rtc"); |