From c4f07ecee22ec720936eb58e7c63b89a1e86bf32 Mon Sep 17 00:00:00 2001 From: Brian Norris Date: Mon, 26 Jun 2017 14:15:03 -0700 Subject: rtc: brcmstb-waketimer: Add Broadcom STB wake-timer This adds support for the Broadcom STB wake-timer which is a timer in the chip's 27Mhz clock domain that offers the ability to wake the system (wake-up source) from suspend states (S2, S3, S5). It is supported using the rtc framework allowing us to configure alarms for system wake-up. Signed-off-by: Brian Norris Signed-off-by: Markus Mayer Signed-off-by: Florian Fainelli Signed-off-by: Arnd Bergmann Signed-off-by: Alexandre Belloni --- drivers/rtc/rtc-brcmstb-waketimer.c | 330 ++++++++++++++++++++++++++++++++++++ 1 file changed, 330 insertions(+) create mode 100644 drivers/rtc/rtc-brcmstb-waketimer.c (limited to 'drivers/rtc/rtc-brcmstb-waketimer.c') diff --git a/drivers/rtc/rtc-brcmstb-waketimer.c b/drivers/rtc/rtc-brcmstb-waketimer.c new file mode 100644 index 000000000000..796ac792a381 --- /dev/null +++ b/drivers/rtc/rtc-brcmstb-waketimer.c @@ -0,0 +1,330 @@ +/* + * Copyright © 2014-2017 Broadcom + * + * 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. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +struct brcmstb_waketmr { + struct rtc_device *rtc; + struct device *dev; + void __iomem *base; + int irq; + struct notifier_block reboot_notifier; + struct clk *clk; + u32 rate; +}; + +#define BRCMSTB_WKTMR_EVENT 0x00 +#define BRCMSTB_WKTMR_COUNTER 0x04 +#define BRCMSTB_WKTMR_ALARM 0x08 +#define BRCMSTB_WKTMR_PRESCALER 0x0C +#define BRCMSTB_WKTMR_PRESCALER_VAL 0x10 + +#define BRCMSTB_WKTMR_DEFAULT_FREQ 27000000 + +static inline void brcmstb_waketmr_clear_alarm(struct brcmstb_waketmr *timer) +{ + writel_relaxed(1, timer->base + BRCMSTB_WKTMR_EVENT); + (void)readl_relaxed(timer->base + BRCMSTB_WKTMR_EVENT); +} + +static void brcmstb_waketmr_set_alarm(struct brcmstb_waketmr *timer, + unsigned int secs) +{ + brcmstb_waketmr_clear_alarm(timer); + + writel_relaxed(secs + 1, timer->base + BRCMSTB_WKTMR_ALARM); +} + +static irqreturn_t brcmstb_waketmr_irq(int irq, void *data) +{ + struct brcmstb_waketmr *timer = data; + + pm_wakeup_event(timer->dev, 0); + + return IRQ_HANDLED; +} + +struct wktmr_time { + u32 sec; + u32 pre; +}; + +static void wktmr_read(struct brcmstb_waketmr *timer, + struct wktmr_time *t) +{ + u32 tmp; + + do { + t->sec = readl_relaxed(timer->base + BRCMSTB_WKTMR_COUNTER); + tmp = readl_relaxed(timer->base + BRCMSTB_WKTMR_PRESCALER_VAL); + } while (tmp >= timer->rate); + + t->pre = timer->rate - tmp; +} + +static int brcmstb_waketmr_prepare_suspend(struct brcmstb_waketmr *timer) +{ + struct device *dev = timer->dev; + int ret = 0; + + if (device_may_wakeup(dev)) { + ret = enable_irq_wake(timer->irq); + if (ret) { + dev_err(dev, "failed to enable wake-up interrupt\n"); + return ret; + } + } + + return ret; +} + +/* If enabled as a wakeup-source, arm the timer when powering off */ +static int brcmstb_waketmr_reboot(struct notifier_block *nb, + unsigned long action, void *data) +{ + struct brcmstb_waketmr *timer; + + timer = container_of(nb, struct brcmstb_waketmr, reboot_notifier); + + /* Set timer for cold boot */ + if (action == SYS_POWER_OFF) + brcmstb_waketmr_prepare_suspend(timer); + + return NOTIFY_DONE; +} + +static int brcmstb_waketmr_gettime(struct device *dev, + struct rtc_time *tm) +{ + struct brcmstb_waketmr *timer = dev_get_drvdata(dev); + struct wktmr_time now; + + wktmr_read(timer, &now); + + rtc_time_to_tm(now.sec, tm); + + return 0; +} + +static int brcmstb_waketmr_settime(struct device *dev, + struct rtc_time *tm) +{ + struct brcmstb_waketmr *timer = dev_get_drvdata(dev); + time64_t sec; + + sec = rtc_tm_to_time64(tm); + + if (sec > U32_MAX || sec < 0) + return -EINVAL; + + writel_relaxed(sec, timer->base + BRCMSTB_WKTMR_COUNTER); + + return 0; +} + +static int brcmstb_waketmr_getalarm(struct device *dev, + struct rtc_wkalrm *alarm) +{ + struct brcmstb_waketmr *timer = dev_get_drvdata(dev); + time64_t sec; + u32 reg; + + sec = readl_relaxed(timer->base + BRCMSTB_WKTMR_ALARM); + if (sec != 0) { + /* Alarm is enabled */ + alarm->enabled = 1; + rtc_time64_to_tm(sec, &alarm->time); + } + + reg = readl_relaxed(timer->base + BRCMSTB_WKTMR_EVENT); + alarm->pending = !!(reg & 1); + + return 0; +} + +static int brcmstb_waketmr_setalarm(struct device *dev, + struct rtc_wkalrm *alarm) +{ + struct brcmstb_waketmr *timer = dev_get_drvdata(dev); + time64_t sec; + + if (alarm->enabled) + sec = rtc_tm_to_time64(&alarm->time); + else + sec = 0; + + if (sec > U32_MAX || sec < 0) + return -EINVAL; + + brcmstb_waketmr_set_alarm(timer, sec); + + return 0; +} + +/* + * Does not do much but keep the RTC class happy. We always support + * alarms. + */ +static int brcmstb_waketmr_alarm_enable(struct device *dev, + unsigned int enabled) +{ + return 0; +} + +static const struct rtc_class_ops brcmstb_waketmr_ops = { + .read_time = brcmstb_waketmr_gettime, + .set_time = brcmstb_waketmr_settime, + .read_alarm = brcmstb_waketmr_getalarm, + .set_alarm = brcmstb_waketmr_setalarm, + .alarm_irq_enable = brcmstb_waketmr_alarm_enable, +}; + +static int brcmstb_waketmr_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct brcmstb_waketmr *timer; + struct resource *res; + int ret; + + timer = devm_kzalloc(dev, sizeof(*timer), GFP_KERNEL); + if (!timer) + return -ENOMEM; + + platform_set_drvdata(pdev, timer); + timer->dev = dev; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + timer->base = devm_ioremap_resource(dev, res); + if (IS_ERR(timer->base)) + return PTR_ERR(timer->base); + + /* + * Set wakeup capability before requesting wakeup interrupt, so we can + * process boot-time "wakeups" (e.g., from S5 soft-off) + */ + device_set_wakeup_capable(dev, true); + device_wakeup_enable(dev); + + timer->irq = platform_get_irq(pdev, 0); + if (timer->irq < 0) + return -ENODEV; + + timer->clk = devm_clk_get(dev, NULL); + if (!IS_ERR(timer->clk)) { + ret = clk_prepare_enable(timer->clk); + if (ret) + return ret; + timer->rate = clk_get_rate(timer->clk); + if (!timer->rate) + timer->rate = BRCMSTB_WKTMR_DEFAULT_FREQ; + } else { + timer->rate = BRCMSTB_WKTMR_DEFAULT_FREQ; + timer->clk = NULL; + } + + ret = devm_request_irq(dev, timer->irq, brcmstb_waketmr_irq, 0, + "brcmstb-waketimer", timer); + if (ret < 0) + return ret; + + timer->reboot_notifier.notifier_call = brcmstb_waketmr_reboot; + register_reboot_notifier(&timer->reboot_notifier); + + timer->rtc = rtc_device_register("brcmstb-waketmr", dev, + &brcmstb_waketmr_ops, THIS_MODULE); + if (IS_ERR(timer->rtc)) { + dev_err(dev, "unable to register device\n"); + unregister_reboot_notifier(&timer->reboot_notifier); + return PTR_ERR(timer->rtc); + } + + dev_info(dev, "registered, with irq %d\n", timer->irq); + + return ret; +} + +static int brcmstb_waketmr_remove(struct platform_device *pdev) +{ + struct brcmstb_waketmr *timer = dev_get_drvdata(&pdev->dev); + + unregister_reboot_notifier(&timer->reboot_notifier); + rtc_device_unregister(timer->rtc); + + return 0; +} + +#ifdef CONFIG_PM_SLEEP +static int brcmstb_waketmr_suspend(struct device *dev) +{ + struct brcmstb_waketmr *timer = dev_get_drvdata(dev); + + return brcmstb_waketmr_prepare_suspend(timer); +} + +static int brcmstb_waketmr_resume(struct device *dev) +{ + struct brcmstb_waketmr *timer = dev_get_drvdata(dev); + int ret; + + if (!device_may_wakeup(dev)) + return 0; + + ret = disable_irq_wake(timer->irq); + + brcmstb_waketmr_clear_alarm(timer); + + return ret; +} +#endif /* CONFIG_PM_SLEEP */ + +static SIMPLE_DEV_PM_OPS(brcmstb_waketmr_pm_ops, + brcmstb_waketmr_suspend, brcmstb_waketmr_resume); + +static const struct of_device_id brcmstb_waketmr_of_match[] = { + { .compatible = "brcm,brcmstb-waketimer" }, + { /* sentinel */ }, +}; + +static struct platform_driver brcmstb_waketmr_driver = { + .probe = brcmstb_waketmr_probe, + .remove = brcmstb_waketmr_remove, + .driver = { + .name = "brcmstb-waketimer", + .pm = &brcmstb_waketmr_pm_ops, + .of_match_table = of_match_ptr(brcmstb_waketmr_of_match), + } +}; +module_platform_driver(brcmstb_waketmr_driver); + +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Brian Norris"); +MODULE_AUTHOR("Markus Mayer"); +MODULE_DESCRIPTION("Wake-up timer driver for STB chips"); -- cgit