1 files changed, 414 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-jz4740.c b/drivers/rtc/rtc-jz4740.c
new file mode 100644
index 000000000..9607e6b6e
--- /dev/null
+++ b/drivers/rtc/rtc-jz4740.c
@@ -0,0 +1,414 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ *  Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de>
+ *  Copyright (C) 2010, Paul Cercueil <paul@crapouillou.net>
+ *	 JZ4740 SoC RTC driver
+ */
+
+#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/pm_wakeirq.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_JZ4760,
+	ID_JZ4780,
+};
+
+struct jz4740_rtc {
+	void __iomem *base;
+	enum jz4740_rtc_type type;
+
+	struct rtc_device *rtc;
+
+	spinlock_t lock;
+};
+
+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 = 10000;
+
+	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 = 10000;
+
+	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_JZ4760)
+		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 (jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SCRATCHPAD) != 0x12345678)
+		return -EINVAL;
+
+	/* 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_time64_to_tm(secs, time);
+
+	return 0;
+}
+
+static int jz4740_rtc_set_time(struct device *dev, struct rtc_time *time)
+{
+	struct jz4740_rtc *rtc = dev_get_drvdata(dev);
+	int ret;
+
+	ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC, rtc_tm_to_time64(time));
+	if (ret)
+		return ret;
+
+	return jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SCRATCHPAD, 0x12345678);
+}
+
+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_time64_to_tm(secs, &alrm->time);
+
+	return 0;
+}
+
+static int jz4740_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	int ret;
+	struct jz4740_rtc *rtc = dev_get_drvdata(dev);
+	uint32_t secs = lower_32_bits(rtc_tm_to_time64(&alrm->time));
+
+	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_time	= jz4740_rtc_set_time,
+	.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)
+{
+	jz4740_rtc_poweroff(dev_for_power_off);
+	kernel_halt();
+}
+
+static void jz4740_rtc_clk_disable(void *data)
+{
+	clk_disable_unprepare(data);
+}
+
+static const struct of_device_id jz4740_rtc_of_match[] = {
+	{ .compatible = "ingenic,jz4740-rtc", .data = (void *)ID_JZ4740 },
+	{ .compatible = "ingenic,jz4760-rtc", .data = (void *)ID_JZ4760 },
+	{ .compatible = "ingenic,jz4780-rtc", .data = (void *)ID_JZ4780 },
+	{},
+};
+MODULE_DEVICE_TABLE(of, jz4740_rtc_of_match);
+
+static void jz4740_rtc_set_wakeup_params(struct jz4740_rtc *rtc,
+					 struct device_node *np,
+					 unsigned long rate)
+{
+	unsigned long wakeup_ticks, reset_ticks;
+	unsigned int min_wakeup_pin_assert_time = 60; /* Default: 60ms */
+	unsigned int reset_pin_assert_time = 100; /* Default: 100ms */
+
+	of_property_read_u32(np, "ingenic,reset-pin-assert-time-ms",
+			     &reset_pin_assert_time);
+	of_property_read_u32(np, "ingenic,min-wakeup-pin-assert-time-ms",
+			     &min_wakeup_pin_assert_time);
+
+	/*
+	 * Set minimum wakeup pin assertion time: 100 ms.
+	 * Range is 0 to 2 sec if RTC is clocked at 32 kHz.
+	 */
+	wakeup_ticks = (min_wakeup_pin_assert_time * rate) / 1000;
+	if (wakeup_ticks < JZ_RTC_WAKEUP_FILTER_MASK)
+		wakeup_ticks &= JZ_RTC_WAKEUP_FILTER_MASK;
+	else
+		wakeup_ticks = JZ_RTC_WAKEUP_FILTER_MASK;
+	jz4740_rtc_reg_write(rtc, JZ_REG_RTC_WAKEUP_FILTER, wakeup_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_ticks = (reset_pin_assert_time * rate) / 1000;
+	if (reset_ticks < JZ_RTC_RESET_COUNTER_MASK)
+		reset_ticks &= JZ_RTC_RESET_COUNTER_MASK;
+	else
+		reset_ticks = JZ_RTC_RESET_COUNTER_MASK;
+	jz4740_rtc_reg_write(rtc, JZ_REG_RTC_RESET_COUNTER, reset_ticks);
+}
+
+static int jz4740_rtc_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct jz4740_rtc *rtc;
+	unsigned long rate;
+	struct clk *clk;
+	int ret, irq;
+
+	rtc = devm_kzalloc(dev, sizeof(*rtc), GFP_KERNEL);
+	if (!rtc)
+		return -ENOMEM;
+
+	rtc->type = (enum jz4740_rtc_type)device_get_match_data(dev);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	rtc->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(rtc->base))
+		return PTR_ERR(rtc->base);
+
+	clk = devm_clk_get(dev, "rtc");
+	if (IS_ERR(clk)) {
+		dev_err(dev, "Failed to get RTC clock\n");
+		return PTR_ERR(clk);
+	}
+
+	ret = clk_prepare_enable(clk);
+	if (ret) {
+		dev_err(dev, "Failed to enable clock\n");
+		return ret;
+	}
+
+	ret = devm_add_action_or_reset(dev, jz4740_rtc_clk_disable, clk);
+	if (ret) {
+		dev_err(dev, "Failed to register devm action\n");
+		return ret;
+	}
+
+	spin_lock_init(&rtc->lock);
+
+	platform_set_drvdata(pdev, rtc);
+
+	device_init_wakeup(dev, 1);
+
+	ret = dev_pm_set_wake_irq(dev, irq);
+	if (ret) {
+		dev_err(dev, "Failed to set wake irq: %d\n", ret);
+		return ret;
+	}
+
+	rtc->rtc = devm_rtc_allocate_device(dev);
+	if (IS_ERR(rtc->rtc)) {
+		ret = PTR_ERR(rtc->rtc);
+		dev_err(dev, "Failed to allocate rtc device: %d\n", ret);
+		return ret;
+	}
+
+	rtc->rtc->ops = &jz4740_rtc_ops;
+	rtc->rtc->range_max = U32_MAX;
+
+	rate = clk_get_rate(clk);
+	jz4740_rtc_set_wakeup_params(rtc, np, rate);
+
+	/* Each 1 Hz pulse should happen after (rate) ticks */
+	jz4740_rtc_reg_write(rtc, JZ_REG_RTC_REGULATOR, rate - 1);
+
+	ret = rtc_register_device(rtc->rtc);
+	if (ret)
+		return ret;
+
+	ret = devm_request_irq(dev, irq, jz4740_rtc_irq, 0,
+			       pdev->name, rtc);
+	if (ret) {
+		dev_err(dev, "Failed to request rtc irq: %d\n", ret);
+		return ret;
+	}
+
+	if (of_device_is_system_power_controller(np)) {
+		dev_for_power_off = dev;
+
+		if (!pm_power_off)
+			pm_power_off = jz4740_rtc_power_off;
+		else
+			dev_warn(dev, "Poweroff handler already present!\n");
+	}
+
+	return 0;
+}
+
+static struct platform_driver jz4740_rtc_driver = {
+	.probe	 = jz4740_rtc_probe,
+	.driver	 = {
+		.name  = "jz4740-rtc",
+		.of_match_table = jz4740_rtc_of_match,
+	},
+};
+
+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");