/* * Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de> * Copyright (C) 2010, Paul Cercueil <paul@crapouillou.net> * JZ4740 SoC RTC driver * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the * Free Software Foundation; either version 2 of the License, or (at your * option) any later version. * * You should have received a copy of the GNU General Public License along * with this program; if not, write to the Free Software Foundation, Inc., * 675 Mass Ave, Cambridge, MA 02139, USA. * */ #include <linux/clk.h> #include <linux/io.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/of_device.h> #include <linux/platform_device.h> #include <linux/reboot.h> #include <linux/rtc.h> #include <linux/slab.h> #include <linux/spinlock.h> #define JZ_REG_RTC_CTRL 0x00 #define JZ_REG_RTC_SEC 0x04 #define JZ_REG_RTC_SEC_ALARM 0x08 #define JZ_REG_RTC_REGULATOR 0x0C #define JZ_REG_RTC_HIBERNATE 0x20 #define JZ_REG_RTC_WAKEUP_FILTER 0x24 #define JZ_REG_RTC_RESET_COUNTER 0x28 #define JZ_REG_RTC_SCRATCHPAD 0x34 /* The following are present on the jz4780 */ #define JZ_REG_RTC_WENR 0x3C #define JZ_RTC_WENR_WEN BIT(31) #define JZ_RTC_CTRL_WRDY BIT(7) #define JZ_RTC_CTRL_1HZ BIT(6) #define JZ_RTC_CTRL_1HZ_IRQ BIT(5) #define JZ_RTC_CTRL_AF BIT(4) #define JZ_RTC_CTRL_AF_IRQ BIT(3) #define JZ_RTC_CTRL_AE BIT(2) #define JZ_RTC_CTRL_ENABLE BIT(0) /* Magic value to enable writes on jz4780 */ #define JZ_RTC_WENR_MAGIC 0xA55A #define JZ_RTC_WAKEUP_FILTER_MASK 0x0000FFE0 #define JZ_RTC_RESET_COUNTER_MASK 0x00000FE0 enum jz4740_rtc_type { ID_JZ4740, ID_JZ4780, }; struct jz4740_rtc { void __iomem *base; enum jz4740_rtc_type type; struct rtc_device *rtc; struct clk *clk; int irq; spinlock_t lock; unsigned int min_wakeup_pin_assert_time; unsigned int reset_pin_assert_time; }; static struct device *dev_for_power_off; static inline uint32_t jz4740_rtc_reg_read(struct jz4740_rtc *rtc, size_t reg) { return readl(rtc->base + reg); } static int jz4740_rtc_wait_write_ready(struct jz4740_rtc *rtc) { uint32_t ctrl; int timeout = 1000; do { ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL); } while (!(ctrl & JZ_RTC_CTRL_WRDY) && --timeout); return timeout ? 0 : -EIO; } static inline int jz4780_rtc_enable_write(struct jz4740_rtc *rtc) { uint32_t ctrl; int ret, timeout = 1000; ret = jz4740_rtc_wait_write_ready(rtc); if (ret != 0) return ret; writel(JZ_RTC_WENR_MAGIC, rtc->base + JZ_REG_RTC_WENR); do { ctrl = readl(rtc->base + JZ_REG_RTC_WENR); } while (!(ctrl & JZ_RTC_WENR_WEN) && --timeout); return timeout ? 0 : -EIO; } static inline int jz4740_rtc_reg_write(struct jz4740_rtc *rtc, size_t reg, uint32_t val) { int ret = 0; if (rtc->type >= ID_JZ4780) ret = jz4780_rtc_enable_write(rtc); if (ret == 0) ret = jz4740_rtc_wait_write_ready(rtc); if (ret == 0) writel(val, rtc->base + reg); return ret; } static int jz4740_rtc_ctrl_set_bits(struct jz4740_rtc *rtc, uint32_t mask, bool set) { int ret; unsigned long flags; uint32_t ctrl; spin_lock_irqsave(&rtc->lock, flags); ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL); /* Don't clear interrupt flags by accident */ ctrl |= JZ_RTC_CTRL_1HZ | JZ_RTC_CTRL_AF; if (set) ctrl |= mask; else ctrl &= ~mask; ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_CTRL, ctrl); spin_unlock_irqrestore(&rtc->lock, flags); return ret; } static int jz4740_rtc_read_time(struct device *dev, struct rtc_time *time) { struct jz4740_rtc *rtc = dev_get_drvdata(dev); uint32_t secs, secs2; int timeout = 5; /* If the seconds register is read while it is updated, it can contain a * bogus value. This can be avoided by making sure that two consecutive * reads have the same value. */ secs = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC); secs2 = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC); while (secs != secs2 && --timeout) { secs = secs2; secs2 = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC); } if (timeout == 0) return -EIO; rtc_time_to_tm(secs, time); return rtc_valid_tm(time); } static int jz4740_rtc_set_mmss(struct device *dev, unsigned long secs) { struct jz4740_rtc *rtc = dev_get_drvdata(dev); return jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC, secs); } static int jz4740_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) { struct jz4740_rtc *rtc = dev_get_drvdata(dev); uint32_t secs; uint32_t ctrl; secs = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC_ALARM); ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL); alrm->enabled = !!(ctrl & JZ_RTC_CTRL_AE); alrm->pending = !!(ctrl & JZ_RTC_CTRL_AF); rtc_time_to_tm(secs, &alrm->time); return rtc_valid_tm(&alrm->time); } static int jz4740_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) { int ret; struct jz4740_rtc *rtc = dev_get_drvdata(dev); unsigned long secs; rtc_tm_to_time(&alrm->time, &secs); ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC_ALARM, secs); if (!ret) ret = jz4740_rtc_ctrl_set_bits(rtc, JZ_RTC_CTRL_AE | JZ_RTC_CTRL_AF_IRQ, alrm->enabled); return ret; } static int jz4740_rtc_alarm_irq_enable(struct device *dev, unsigned int enable) { struct jz4740_rtc *rtc = dev_get_drvdata(dev); return jz4740_rtc_ctrl_set_bits(rtc, JZ_RTC_CTRL_AF_IRQ, enable); } static const struct rtc_class_ops jz4740_rtc_ops = { .read_time = jz4740_rtc_read_time, .set_mmss = jz4740_rtc_set_mmss, .read_alarm = jz4740_rtc_read_alarm, .set_alarm = jz4740_rtc_set_alarm, .alarm_irq_enable = jz4740_rtc_alarm_irq_enable, }; static irqreturn_t jz4740_rtc_irq(int irq, void *data) { struct jz4740_rtc *rtc = data; uint32_t ctrl; unsigned long events = 0; ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL); if (ctrl & JZ_RTC_CTRL_1HZ) events |= (RTC_UF | RTC_IRQF); if (ctrl & JZ_RTC_CTRL_AF) events |= (RTC_AF | RTC_IRQF); rtc_update_irq(rtc->rtc, 1, events); jz4740_rtc_ctrl_set_bits(rtc, JZ_RTC_CTRL_1HZ | JZ_RTC_CTRL_AF, false); return IRQ_HANDLED; } static void jz4740_rtc_poweroff(struct device *dev) { struct jz4740_rtc *rtc = dev_get_drvdata(dev); jz4740_rtc_reg_write(rtc, JZ_REG_RTC_HIBERNATE, 1); } static void jz4740_rtc_power_off(void) { struct jz4740_rtc *rtc = dev_get_drvdata(dev_for_power_off); unsigned long rtc_rate; unsigned long wakeup_filter_ticks; unsigned long reset_counter_ticks; clk_prepare_enable(rtc->clk); rtc_rate = clk_get_rate(rtc->clk); /* * Set minimum wakeup pin assertion time: 100 ms. * Range is 0 to 2 sec if RTC is clocked at 32 kHz. */ wakeup_filter_ticks = (rtc->min_wakeup_pin_assert_time * rtc_rate) / 1000; if (wakeup_filter_ticks < JZ_RTC_WAKEUP_FILTER_MASK) wakeup_filter_ticks &= JZ_RTC_WAKEUP_FILTER_MASK; else wakeup_filter_ticks = JZ_RTC_WAKEUP_FILTER_MASK; jz4740_rtc_reg_write(rtc, JZ_REG_RTC_WAKEUP_FILTER, wakeup_filter_ticks); /* * Set reset pin low-level assertion time after wakeup: 60 ms. * Range is 0 to 125 ms if RTC is clocked at 32 kHz. */ reset_counter_ticks = (rtc->reset_pin_assert_time * rtc_rate) / 1000; if (reset_counter_ticks < JZ_RTC_RESET_COUNTER_MASK) reset_counter_ticks &= JZ_RTC_RESET_COUNTER_MASK; else reset_counter_ticks = JZ_RTC_RESET_COUNTER_MASK; jz4740_rtc_reg_write(rtc, JZ_REG_RTC_RESET_COUNTER, reset_counter_ticks); jz4740_rtc_poweroff(dev_for_power_off); kernel_halt(); } static const struct of_device_id jz4740_rtc_of_match[] = { { .compatible = "ingenic,jz4740-rtc", .data = (void *)ID_JZ4740 }, { .compatible = "ingenic,jz4780-rtc", .data = (void *)ID_JZ4780 }, {}, }; MODULE_DEVICE_TABLE(of, jz4740_rtc_of_match); static int jz4740_rtc_probe(struct platform_device *pdev) { int ret; struct jz4740_rtc *rtc; uint32_t scratchpad; struct resource *mem; const struct platform_device_id *id = platform_get_device_id(pdev); const struct of_device_id *of_id = of_match_device( jz4740_rtc_of_match, &pdev->dev); struct device_node *np = pdev->dev.of_node; rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL); if (!rtc) return -ENOMEM; if (of_id) rtc->type = (enum jz4740_rtc_type)of_id->data; else rtc->type = id->driver_data; rtc->irq = platform_get_irq(pdev, 0); if (rtc->irq < 0) { dev_err(&pdev->dev, "Failed to get platform irq\n"); return -ENOENT; } mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); rtc->base = devm_ioremap_resource(&pdev->dev, mem); if (IS_ERR(rtc->base)) return PTR_ERR(rtc->base); rtc->clk = devm_clk_get(&pdev->dev, "rtc"); if (IS_ERR(rtc->clk)) { dev_err(&pdev->dev, "Failed to get RTC clock\n"); return PTR_ERR(rtc->clk); } spin_lock_init(&rtc->lock); platform_set_drvdata(pdev, rtc); device_init_wakeup(&pdev->dev, 1); rtc->rtc = devm_rtc_device_register(&pdev->dev, pdev->name, &jz4740_rtc_ops, THIS_MODULE); if (IS_ERR(rtc->rtc)) { ret = PTR_ERR(rtc->rtc); dev_err(&pdev->dev, "Failed to register rtc device: %d\n", ret); return ret; } ret = devm_request_irq(&pdev->dev, rtc->irq, jz4740_rtc_irq, 0, pdev->name, rtc); if (ret) { dev_err(&pdev->dev, "Failed to request rtc irq: %d\n", ret); return ret; } scratchpad = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SCRATCHPAD); if (scratchpad != 0x12345678) { ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SCRATCHPAD, 0x12345678); ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC, 0); if (ret) { dev_err(&pdev->dev, "Could not write write to RTC registers\n"); return ret; } } if (np && of_device_is_system_power_controller(np)) { if (!pm_power_off) { /* Default: 60ms */ rtc->reset_pin_assert_time = 60; of_property_read_u32(np, "reset-pin-assert-time-ms", &rtc->reset_pin_assert_time); /* Default: 100ms */ rtc->min_wakeup_pin_assert_time = 100; of_property_read_u32(np, "min-wakeup-pin-assert-time-ms", &rtc->min_wakeup_pin_assert_time); dev_for_power_off = &pdev->dev; pm_power_off = jz4740_rtc_power_off; } else { dev_warn(&pdev->dev, "Poweroff handler already present!\n"); } } return 0; } #ifdef CONFIG_PM static int jz4740_rtc_suspend(struct device *dev) { struct jz4740_rtc *rtc = dev_get_drvdata(dev); if (device_may_wakeup(dev)) enable_irq_wake(rtc->irq); return 0; } static int jz4740_rtc_resume(struct device *dev) { struct jz4740_rtc *rtc = dev_get_drvdata(dev); if (device_may_wakeup(dev)) disable_irq_wake(rtc->irq); return 0; } static const struct dev_pm_ops jz4740_pm_ops = { .suspend = jz4740_rtc_suspend, .resume = jz4740_rtc_resume, }; #define JZ4740_RTC_PM_OPS (&jz4740_pm_ops) #else #define JZ4740_RTC_PM_OPS NULL #endif /* CONFIG_PM */ static const struct platform_device_id jz4740_rtc_ids[] = { { "jz4740-rtc", ID_JZ4740 }, { "jz4780-rtc", ID_JZ4780 }, {} }; MODULE_DEVICE_TABLE(platform, jz4740_rtc_ids); static struct platform_driver jz4740_rtc_driver = { .probe = jz4740_rtc_probe, .driver = { .name = "jz4740-rtc", .pm = JZ4740_RTC_PM_OPS, .of_match_table = of_match_ptr(jz4740_rtc_of_match), }, .id_table = jz4740_rtc_ids, }; module_platform_driver(jz4740_rtc_driver); MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("RTC driver for the JZ4740 SoC\n"); MODULE_ALIAS("platform:jz4740-rtc");