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![Bartosz Golaszewski](/assets/img/avatar_default.png)
rtc_register_device() is a managed interface but it doesn't use devres by itself - instead it marks an rtc_device as "registered" and the devres callback for devm_rtc_allocate_device() takes care of resource release. This doesn't correspond with the design behind devres where managed structures should not be aware of being managed. The correct solution here is to register a separate devres callback for unregistering the device. While at it: rename rtc_register_device() to devm_rtc_register_device() and add it to the list of managed interfaces in devres.rst. This way we can avoid any potential confusion of driver developers who may expect there to exist a corresponding unregister function. Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20201109163409.24301-8-brgl@bgdev.pl
414 lines
9.8 KiB
C
414 lines
9.8 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de>
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* Copyright (C) 2010, Paul Cercueil <paul@crapouillou.net>
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* JZ4740 SoC RTC driver
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*/
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#include <linux/clk.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/of_device.h>
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#include <linux/platform_device.h>
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#include <linux/pm_wakeirq.h>
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#include <linux/reboot.h>
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#include <linux/rtc.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#define JZ_REG_RTC_CTRL 0x00
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#define JZ_REG_RTC_SEC 0x04
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#define JZ_REG_RTC_SEC_ALARM 0x08
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#define JZ_REG_RTC_REGULATOR 0x0C
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#define JZ_REG_RTC_HIBERNATE 0x20
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#define JZ_REG_RTC_WAKEUP_FILTER 0x24
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#define JZ_REG_RTC_RESET_COUNTER 0x28
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#define JZ_REG_RTC_SCRATCHPAD 0x34
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/* The following are present on the jz4780 */
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#define JZ_REG_RTC_WENR 0x3C
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#define JZ_RTC_WENR_WEN BIT(31)
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#define JZ_RTC_CTRL_WRDY BIT(7)
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#define JZ_RTC_CTRL_1HZ BIT(6)
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#define JZ_RTC_CTRL_1HZ_IRQ BIT(5)
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#define JZ_RTC_CTRL_AF BIT(4)
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#define JZ_RTC_CTRL_AF_IRQ BIT(3)
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#define JZ_RTC_CTRL_AE BIT(2)
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#define JZ_RTC_CTRL_ENABLE BIT(0)
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/* Magic value to enable writes on jz4780 */
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#define JZ_RTC_WENR_MAGIC 0xA55A
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#define JZ_RTC_WAKEUP_FILTER_MASK 0x0000FFE0
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#define JZ_RTC_RESET_COUNTER_MASK 0x00000FE0
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enum jz4740_rtc_type {
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ID_JZ4740,
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ID_JZ4760,
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ID_JZ4780,
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};
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struct jz4740_rtc {
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void __iomem *base;
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enum jz4740_rtc_type type;
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struct rtc_device *rtc;
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spinlock_t lock;
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};
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static struct device *dev_for_power_off;
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static inline uint32_t jz4740_rtc_reg_read(struct jz4740_rtc *rtc, size_t reg)
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{
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return readl(rtc->base + reg);
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}
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static int jz4740_rtc_wait_write_ready(struct jz4740_rtc *rtc)
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{
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uint32_t ctrl;
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int timeout = 10000;
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do {
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ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
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} while (!(ctrl & JZ_RTC_CTRL_WRDY) && --timeout);
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return timeout ? 0 : -EIO;
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}
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static inline int jz4780_rtc_enable_write(struct jz4740_rtc *rtc)
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{
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uint32_t ctrl;
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int ret, timeout = 10000;
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ret = jz4740_rtc_wait_write_ready(rtc);
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if (ret != 0)
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return ret;
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writel(JZ_RTC_WENR_MAGIC, rtc->base + JZ_REG_RTC_WENR);
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do {
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ctrl = readl(rtc->base + JZ_REG_RTC_WENR);
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} while (!(ctrl & JZ_RTC_WENR_WEN) && --timeout);
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return timeout ? 0 : -EIO;
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}
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static inline int jz4740_rtc_reg_write(struct jz4740_rtc *rtc, size_t reg,
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uint32_t val)
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{
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int ret = 0;
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if (rtc->type >= ID_JZ4760)
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ret = jz4780_rtc_enable_write(rtc);
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if (ret == 0)
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ret = jz4740_rtc_wait_write_ready(rtc);
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if (ret == 0)
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writel(val, rtc->base + reg);
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return ret;
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}
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static int jz4740_rtc_ctrl_set_bits(struct jz4740_rtc *rtc, uint32_t mask,
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bool set)
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{
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int ret;
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unsigned long flags;
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uint32_t ctrl;
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spin_lock_irqsave(&rtc->lock, flags);
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ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
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/* Don't clear interrupt flags by accident */
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ctrl |= JZ_RTC_CTRL_1HZ | JZ_RTC_CTRL_AF;
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if (set)
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ctrl |= mask;
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else
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ctrl &= ~mask;
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ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_CTRL, ctrl);
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spin_unlock_irqrestore(&rtc->lock, flags);
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return ret;
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}
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static int jz4740_rtc_read_time(struct device *dev, struct rtc_time *time)
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{
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struct jz4740_rtc *rtc = dev_get_drvdata(dev);
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uint32_t secs, secs2;
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int timeout = 5;
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if (jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SCRATCHPAD) != 0x12345678)
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return -EINVAL;
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/* If the seconds register is read while it is updated, it can contain a
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* bogus value. This can be avoided by making sure that two consecutive
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* reads have the same value.
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*/
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secs = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC);
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secs2 = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC);
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while (secs != secs2 && --timeout) {
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secs = secs2;
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secs2 = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC);
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}
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if (timeout == 0)
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return -EIO;
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rtc_time64_to_tm(secs, time);
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return 0;
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}
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static int jz4740_rtc_set_time(struct device *dev, struct rtc_time *time)
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{
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struct jz4740_rtc *rtc = dev_get_drvdata(dev);
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int ret;
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ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC, rtc_tm_to_time64(time));
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if (ret)
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return ret;
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return jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SCRATCHPAD, 0x12345678);
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}
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static int jz4740_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
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{
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struct jz4740_rtc *rtc = dev_get_drvdata(dev);
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uint32_t secs;
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uint32_t ctrl;
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secs = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC_ALARM);
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ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
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alrm->enabled = !!(ctrl & JZ_RTC_CTRL_AE);
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alrm->pending = !!(ctrl & JZ_RTC_CTRL_AF);
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rtc_time64_to_tm(secs, &alrm->time);
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return 0;
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}
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static int jz4740_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
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{
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int ret;
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struct jz4740_rtc *rtc = dev_get_drvdata(dev);
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uint32_t secs = lower_32_bits(rtc_tm_to_time64(&alrm->time));
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ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC_ALARM, secs);
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if (!ret)
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ret = jz4740_rtc_ctrl_set_bits(rtc,
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JZ_RTC_CTRL_AE | JZ_RTC_CTRL_AF_IRQ, alrm->enabled);
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return ret;
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}
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static int jz4740_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
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{
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struct jz4740_rtc *rtc = dev_get_drvdata(dev);
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return jz4740_rtc_ctrl_set_bits(rtc, JZ_RTC_CTRL_AF_IRQ, enable);
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}
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static const struct rtc_class_ops jz4740_rtc_ops = {
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.read_time = jz4740_rtc_read_time,
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.set_time = jz4740_rtc_set_time,
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.read_alarm = jz4740_rtc_read_alarm,
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.set_alarm = jz4740_rtc_set_alarm,
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.alarm_irq_enable = jz4740_rtc_alarm_irq_enable,
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};
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static irqreturn_t jz4740_rtc_irq(int irq, void *data)
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{
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struct jz4740_rtc *rtc = data;
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uint32_t ctrl;
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unsigned long events = 0;
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ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
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if (ctrl & JZ_RTC_CTRL_1HZ)
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events |= (RTC_UF | RTC_IRQF);
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if (ctrl & JZ_RTC_CTRL_AF)
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events |= (RTC_AF | RTC_IRQF);
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rtc_update_irq(rtc->rtc, 1, events);
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jz4740_rtc_ctrl_set_bits(rtc, JZ_RTC_CTRL_1HZ | JZ_RTC_CTRL_AF, false);
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return IRQ_HANDLED;
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}
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static void jz4740_rtc_poweroff(struct device *dev)
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{
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struct jz4740_rtc *rtc = dev_get_drvdata(dev);
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jz4740_rtc_reg_write(rtc, JZ_REG_RTC_HIBERNATE, 1);
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}
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static void jz4740_rtc_power_off(void)
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{
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jz4740_rtc_poweroff(dev_for_power_off);
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kernel_halt();
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}
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static void jz4740_rtc_clk_disable(void *data)
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{
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clk_disable_unprepare(data);
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}
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static const struct of_device_id jz4740_rtc_of_match[] = {
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{ .compatible = "ingenic,jz4740-rtc", .data = (void *)ID_JZ4740 },
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{ .compatible = "ingenic,jz4760-rtc", .data = (void *)ID_JZ4760 },
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{ .compatible = "ingenic,jz4780-rtc", .data = (void *)ID_JZ4780 },
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{},
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};
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MODULE_DEVICE_TABLE(of, jz4740_rtc_of_match);
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static void jz4740_rtc_set_wakeup_params(struct jz4740_rtc *rtc,
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struct device_node *np,
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unsigned long rate)
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{
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unsigned long wakeup_ticks, reset_ticks;
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unsigned int min_wakeup_pin_assert_time = 60; /* Default: 60ms */
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unsigned int reset_pin_assert_time = 100; /* Default: 100ms */
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of_property_read_u32(np, "ingenic,reset-pin-assert-time-ms",
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&reset_pin_assert_time);
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of_property_read_u32(np, "ingenic,min-wakeup-pin-assert-time-ms",
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&min_wakeup_pin_assert_time);
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/*
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* Set minimum wakeup pin assertion time: 100 ms.
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* Range is 0 to 2 sec if RTC is clocked at 32 kHz.
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*/
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wakeup_ticks = (min_wakeup_pin_assert_time * rate) / 1000;
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if (wakeup_ticks < JZ_RTC_WAKEUP_FILTER_MASK)
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wakeup_ticks &= JZ_RTC_WAKEUP_FILTER_MASK;
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else
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wakeup_ticks = JZ_RTC_WAKEUP_FILTER_MASK;
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jz4740_rtc_reg_write(rtc, JZ_REG_RTC_WAKEUP_FILTER, wakeup_ticks);
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/*
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* Set reset pin low-level assertion time after wakeup: 60 ms.
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* Range is 0 to 125 ms if RTC is clocked at 32 kHz.
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*/
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reset_ticks = (reset_pin_assert_time * rate) / 1000;
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if (reset_ticks < JZ_RTC_RESET_COUNTER_MASK)
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reset_ticks &= JZ_RTC_RESET_COUNTER_MASK;
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else
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reset_ticks = JZ_RTC_RESET_COUNTER_MASK;
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jz4740_rtc_reg_write(rtc, JZ_REG_RTC_RESET_COUNTER, reset_ticks);
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}
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static int jz4740_rtc_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct device_node *np = dev->of_node;
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struct jz4740_rtc *rtc;
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unsigned long rate;
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struct clk *clk;
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int ret, irq;
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rtc = devm_kzalloc(dev, sizeof(*rtc), GFP_KERNEL);
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if (!rtc)
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return -ENOMEM;
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rtc->type = (enum jz4740_rtc_type)device_get_match_data(dev);
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irq = platform_get_irq(pdev, 0);
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if (irq < 0)
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return irq;
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rtc->base = devm_platform_ioremap_resource(pdev, 0);
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if (IS_ERR(rtc->base))
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return PTR_ERR(rtc->base);
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clk = devm_clk_get(dev, "rtc");
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if (IS_ERR(clk)) {
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dev_err(dev, "Failed to get RTC clock\n");
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return PTR_ERR(clk);
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}
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ret = clk_prepare_enable(clk);
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if (ret) {
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dev_err(dev, "Failed to enable clock\n");
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return ret;
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}
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ret = devm_add_action_or_reset(dev, jz4740_rtc_clk_disable, clk);
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if (ret) {
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dev_err(dev, "Failed to register devm action\n");
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return ret;
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}
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spin_lock_init(&rtc->lock);
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platform_set_drvdata(pdev, rtc);
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device_init_wakeup(dev, 1);
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ret = dev_pm_set_wake_irq(dev, irq);
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if (ret) {
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dev_err(dev, "Failed to set wake irq: %d\n", ret);
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return ret;
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}
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rtc->rtc = devm_rtc_allocate_device(dev);
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if (IS_ERR(rtc->rtc)) {
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ret = PTR_ERR(rtc->rtc);
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dev_err(dev, "Failed to allocate rtc device: %d\n", ret);
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return ret;
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}
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rtc->rtc->ops = &jz4740_rtc_ops;
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rtc->rtc->range_max = U32_MAX;
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rate = clk_get_rate(clk);
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jz4740_rtc_set_wakeup_params(rtc, np, rate);
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/* Each 1 Hz pulse should happen after (rate) ticks */
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jz4740_rtc_reg_write(rtc, JZ_REG_RTC_REGULATOR, rate - 1);
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ret = devm_rtc_register_device(rtc->rtc);
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if (ret)
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return ret;
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ret = devm_request_irq(dev, irq, jz4740_rtc_irq, 0,
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pdev->name, rtc);
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if (ret) {
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dev_err(dev, "Failed to request rtc irq: %d\n", ret);
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return ret;
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}
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if (of_device_is_system_power_controller(np)) {
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dev_for_power_off = dev;
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if (!pm_power_off)
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pm_power_off = jz4740_rtc_power_off;
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else
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dev_warn(dev, "Poweroff handler already present!\n");
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}
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return 0;
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}
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static struct platform_driver jz4740_rtc_driver = {
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.probe = jz4740_rtc_probe,
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.driver = {
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.name = "jz4740-rtc",
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.of_match_table = jz4740_rtc_of_match,
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},
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};
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module_platform_driver(jz4740_rtc_driver);
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MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("RTC driver for the JZ4740 SoC\n");
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MODULE_ALIAS("platform:jz4740-rtc");
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