mvebu: add support for the in-CPU RTC on the Armada 38x

Signed-off-by: Imre Kaloz <kaloz@openwrt.org> SVN-Revision: 45415

mvebu: add support for the in-CPU RTC on the Armada 38x
Signed-off-by: Imre Kaloz <kaloz@openwrt.org> SVN-Revision: 45415
8c684f42 · Imre Kaloz · c9e6c7c8 · 8c684f42 · 8c684f42
Commit 8c684f42 authored 9 years ago by Imre Kaloz
--- a/package/kernel/linux/modules/other.mk
+++ b/package/kernel/linux/modules/other.mk
@@ -573,6 +573,23 @@ endef

 $(eval $(call KernelPackage,rtc-marvell))

+
+define KernelPackage/rtc-armada38x
+  SUBMENU:=$(OTHER_MENU)
+  TITLE:=Marvell Armada 38x SoC built-in RTC support
+  DEPENDS:=@RTC_SUPPORT @TARGET_mvebu
+  KCONFIG:=CONFIG_RTC_DRV_ARMADA38X
+  FILES:=$(LINUX_DIR)/drivers/rtc/rtc-armada38x.ko
+  AUTOLOAD:=$(call AutoProbe,rtc-armada38x)
+endef
+
+define KernelPackage/rtc-armada38x/description
+ Kernel module for Marvell Armada 38x SoC built-in RTC.
+endef
+
+$(eval $(call KernelPackage,rtc-armada38x))
+
+
 define KernelPackage/rtc-pcf8563
  SUBMENU:=$(OTHER_MENU)
  TITLE:=Philips PCF8563/Epson RTC8564 RTC support

--- a/target/linux/mvebu/patches-3.18/600-armada_38x_rtc.patch
+++ b/target/linux/mvebu/patches-3.18/600-armada_38x_rtc.patch
+--- /dev/null
+++ b/Documentation/devicetree/bindings/rtc/armada-380-rtc.txt
+@@ -0,0 +1,22 @@
+* Real Time Clock of the Armada 38x SoCs
+
+RTC controller for the Armada 38x SoCs
+
+Required properties:
+- compatible : Should be "marvell,armada-380-rtc"
+- reg: a list of base address and size pairs, one for each entry in
+  reg-names
+- reg names: should contain:
+  * "rtc" for the RTC registers
+  * "rtc-soc" for the SoC related registers and among them the one
+    related to the interrupt.
+- interrupts: IRQ line for the RTC.
+
+Example:
+
+rtc@a3800 {
+	compatible = "marvell,armada-380-rtc";
+	reg = <0xa3800 0x20>, <0x184a0 0x0c>;
+	reg-names = "rtc", "rtc-soc";
+	interrupts = <GIC_SPI 21 IRQ_TYPE_LEVEL_HIGH>;
+};
+--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
+@@ -1262,6 +1262,16 @@ config RTC_DRV_MV
+ 	  This driver can also be built as a module. If so, the module
+ 	  will be called rtc-mv.
+ 
+config RTC_DRV_ARMADA38X
+	tristate "Armada 38x Marvell SoC RTC"
+	depends on ARCH_MVEBU
+	help
+	  If you say yes here you will get support for the in-chip RTC
+	  that can be found in the Armada 38x Marvell's SoC device
+
+	  This driver can also be built as a module. If so, the module
+	  will be called armada38x-rtc.
+
+ config RTC_DRV_PS3
+ 	tristate "PS3 RTC"
+ 	depends on PPC_PS3
+--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
+@@ -24,6 +24,7 @@ obj-$(CONFIG_RTC_DRV_88PM860X)  += rtc-8
+ obj-$(CONFIG_RTC_DRV_88PM80X)	+= rtc-88pm80x.o
+ obj-$(CONFIG_RTC_DRV_AB3100)	+= rtc-ab3100.o
+ obj-$(CONFIG_RTC_DRV_AB8500)	+= rtc-ab8500.o
+obj-$(CONFIG_RTC_DRV_ARMADA38X)	+= rtc-armada38x.o
+ obj-$(CONFIG_RTC_DRV_AS3722)	+= rtc-as3722.o
+ obj-$(CONFIG_RTC_DRV_AT32AP700X)+= rtc-at32ap700x.o
+ obj-$(CONFIG_RTC_DRV_AT91RM9200)+= rtc-at91rm9200.o
+--- /dev/null
+++ b/drivers/rtc/rtc-armada38x.c
+@@ -0,0 +1,320 @@
+/*
+ * RTC driver for the Armada 38x Marvell SoCs
+ *
+ * Copyright (C) 2015 Marvell
+ *
+ * Gregory Clement <gregory.clement@free-electrons.com>
+ *
+ * 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.
+ *
+ */
+
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+
+#define RTC_STATUS	    0x0
+#define RTC_STATUS_ALARM1	    BIT(0)
+#define RTC_STATUS_ALARM2	    BIT(1)
+#define RTC_IRQ1_CONF	    0x4
+#define RTC_IRQ1_AL_EN		    BIT(0)
+#define RTC_IRQ1_FREQ_EN	    BIT(1)
+#define RTC_IRQ1_FREQ_1HZ	    BIT(2)
+#define RTC_TIME	    0xC
+#define RTC_ALARM1	    0x10
+
+#define SOC_RTC_INTERRUPT   0x8
+#define SOC_RTC_ALARM1		BIT(0)
+#define SOC_RTC_ALARM2		BIT(1)
+#define SOC_RTC_ALARM1_MASK	BIT(2)
+#define SOC_RTC_ALARM2_MASK	BIT(3)
+
+struct armada38x_rtc {
+	struct rtc_device   *rtc_dev;
+	void __iomem	    *regs;
+	void __iomem	    *regs_soc;
+	spinlock_t	    lock;
+	int		    irq;
+};
+
+/*
+ * According to the datasheet, the OS should wait 5us after every
+ * register write to the RTC hard macro so that the required update
+ * can occur without holding off the system bus
+ */
+static void rtc_delayed_write(u32 val, struct armada38x_rtc *rtc, int offset)
+{
+	writel(val, rtc->regs + offset);
+	udelay(5);
+}
+
+static int armada38x_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	struct armada38x_rtc *rtc = dev_get_drvdata(dev);
+	unsigned long time, time_check, flags;
+
+	spin_lock_irqsave(&rtc->lock, flags);
+
+	time = readl(rtc->regs + RTC_TIME);
+	/*
+	 * WA for failing time set attempts. As stated in HW ERRATA if
+	 * more than one second between two time reads is detected
+	 * then read once again.
+	 */
+	time_check = readl(rtc->regs + RTC_TIME);
+	if ((time_check - time) > 1)
+		time_check = readl(rtc->regs + RTC_TIME);
+
+	spin_unlock_irqrestore(&rtc->lock, flags);
+
+	rtc_time_to_tm(time_check, tm);
+
+	return 0;
+}
+
+static int armada38x_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct armada38x_rtc *rtc = dev_get_drvdata(dev);
+	int ret = 0;
+	unsigned long time, flags;
+
+	ret = rtc_tm_to_time(tm, &time);
+
+	if (ret)
+		goto out;
+	/*
+	 * Setting the RTC time not always succeeds. According to the
+	 * errata we need to first write on the status register and
+	 * then wait for 100ms before writing to the time register to be
+	 * sure that the data will be taken into account.
+	 */
+	spin_lock_irqsave(&rtc->lock, flags);
+
+	rtc_delayed_write(0, rtc, RTC_STATUS);
+
+	spin_unlock_irqrestore(&rtc->lock, flags);
+
+	msleep(100);
+
+	spin_lock_irqsave(&rtc->lock, flags);
+
+	rtc_delayed_write(time, rtc, RTC_TIME);
+
+	spin_unlock_irqrestore(&rtc->lock, flags);
+out:
+	return ret;
+}
+
+static int armada38x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct armada38x_rtc *rtc = dev_get_drvdata(dev);
+	unsigned long time, flags;
+	u32 val;
+
+	spin_lock_irqsave(&rtc->lock, flags);
+
+	time = readl(rtc->regs + RTC_ALARM1);
+	val = readl(rtc->regs + RTC_IRQ1_CONF) & RTC_IRQ1_AL_EN;
+
+	spin_unlock_irqrestore(&rtc->lock, flags);
+
+	alrm->enabled = val ? 1 : 0;
+	rtc_time_to_tm(time,  &alrm->time);
+
+	return 0;
+}
+
+static int armada38x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct armada38x_rtc *rtc = dev_get_drvdata(dev);
+	unsigned long time, flags;
+	int ret = 0;
+	u32 val;
+
+	ret = rtc_tm_to_time(&alrm->time, &time);
+
+	if (ret)
+		goto out;
+
+	spin_lock_irqsave(&rtc->lock, flags);
+
+	rtc_delayed_write(time, rtc, RTC_ALARM1);
+
+	if (alrm->enabled) {
+			rtc_delayed_write(RTC_IRQ1_AL_EN, rtc, RTC_IRQ1_CONF);
+			val = readl(rtc->regs_soc + SOC_RTC_INTERRUPT);
+			writel(val | SOC_RTC_ALARM1_MASK,
+			       rtc->regs_soc + SOC_RTC_INTERRUPT);
+	}
+
+	spin_unlock_irqrestore(&rtc->lock, flags);
+
+out:
+	return ret;
+}
+
+static int armada38x_rtc_alarm_irq_enable(struct device *dev,
+					 unsigned int enabled)
+{
+	struct armada38x_rtc *rtc = dev_get_drvdata(dev);
+	unsigned long flags;
+
+	spin_lock_irqsave(&rtc->lock, flags);
+
+	if (enabled)
+		rtc_delayed_write(RTC_IRQ1_AL_EN, rtc, RTC_IRQ1_CONF);
+	else
+		rtc_delayed_write(0, rtc, RTC_IRQ1_CONF);
+
+	spin_unlock_irqrestore(&rtc->lock, flags);
+
+	return 0;
+}
+
+static irqreturn_t armada38x_rtc_alarm_irq(int irq, void *data)
+{
+	struct armada38x_rtc *rtc = data;
+	u32 val;
+	int event = RTC_IRQF | RTC_AF;
+
+	dev_dbg(&rtc->rtc_dev->dev, "%s:irq(%d)\n", __func__, irq);
+
+	spin_lock(&rtc->lock);
+
+	val = readl(rtc->regs_soc + SOC_RTC_INTERRUPT);
+
+	writel(val & ~SOC_RTC_ALARM1, rtc->regs_soc + SOC_RTC_INTERRUPT);
+	val = readl(rtc->regs + RTC_IRQ1_CONF);
+	/* disable all the interrupts for alarm 1 */
+	rtc_delayed_write(0, rtc, RTC_IRQ1_CONF);
+	/* Ack the event */
+	rtc_delayed_write(RTC_STATUS_ALARM1, rtc, RTC_STATUS);
+
+	spin_unlock(&rtc->lock);
+
+	if (val & RTC_IRQ1_FREQ_EN) {
+		if (val & RTC_IRQ1_FREQ_1HZ)
+			event |= RTC_UF;
+		else
+			event |= RTC_PF;
+	}
+
+	rtc_update_irq(rtc->rtc_dev, 1, event);
+
+	return IRQ_HANDLED;
+}
+
+static struct rtc_class_ops armada38x_rtc_ops = {
+	.read_time = armada38x_rtc_read_time,
+	.set_time = armada38x_rtc_set_time,
+	.read_alarm = armada38x_rtc_read_alarm,
+	.set_alarm = armada38x_rtc_set_alarm,
+	.alarm_irq_enable = armada38x_rtc_alarm_irq_enable,
+};
+
+static __init int armada38x_rtc_probe(struct platform_device *pdev)
+{
+	struct resource *res;
+	struct armada38x_rtc *rtc;
+	int ret;
+
+	rtc = devm_kzalloc(&pdev->dev, sizeof(struct armada38x_rtc),
+			    GFP_KERNEL);
+	if (!rtc)
+		return -ENOMEM;
+
+	spin_lock_init(&rtc->lock);
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rtc");
+	rtc->regs = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(rtc->regs))
+		return PTR_ERR(rtc->regs);
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rtc-soc");
+	rtc->regs_soc = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(rtc->regs_soc))
+		return PTR_ERR(rtc->regs_soc);
+
+	rtc->irq = platform_get_irq(pdev, 0);
+
+	if (rtc->irq < 0) {
+		dev_err(&pdev->dev, "no irq\n");
+		return rtc->irq;
+	}
+	if (devm_request_irq(&pdev->dev, rtc->irq, armada38x_rtc_alarm_irq,
+				0, pdev->name, rtc) < 0) {
+		dev_warn(&pdev->dev, "Interrupt not available.\n");
+		rtc->irq = -1;
+		/*
+		 * If there is no interrupt available then we can't
+		 * use the alarm
+		 */
+		armada38x_rtc_ops.set_alarm = NULL;
+		armada38x_rtc_ops.alarm_irq_enable = NULL;
+	}
+	platform_set_drvdata(pdev, rtc);
+	if (rtc->irq != -1)
+		device_init_wakeup(&pdev->dev, 1);
+
+	rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, pdev->name,
+					&armada38x_rtc_ops, THIS_MODULE);
+	if (IS_ERR(rtc->rtc_dev)) {
+		ret = PTR_ERR(rtc->rtc_dev);
+		dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
+		return ret;
+	}
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int armada38x_rtc_suspend(struct device *dev)
+{
+	if (device_may_wakeup(dev)) {
+		struct armada38x_rtc *rtc = dev_get_drvdata(dev);
+
+		return enable_irq_wake(rtc->irq);
+	}
+
+	return 0;
+}
+
+static int armada38x_rtc_resume(struct device *dev)
+{
+	if (device_may_wakeup(dev)) {
+		struct armada38x_rtc *rtc = dev_get_drvdata(dev);
+
+		return disable_irq_wake(rtc->irq);
+	}
+
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(armada38x_rtc_pm_ops,
+			 armada38x_rtc_suspend, armada38x_rtc_resume);
+
+#ifdef CONFIG_OF
+static const struct of_device_id armada38x_rtc_of_match_table[] = {
+	{ .compatible = "marvell,armada-380-rtc", },
+	{}
+};
+#endif
+
+static struct platform_driver armada38x_rtc_driver = {
+	.driver		= {
+		.name	= "armada38x-rtc",
+		.pm	= &armada38x_rtc_pm_ops,
+		.of_match_table = of_match_ptr(armada38x_rtc_of_match_table),
+	},
+};
+
+module_platform_driver_probe(armada38x_rtc_driver, armada38x_rtc_probe);
+
+MODULE_DESCRIPTION("Marvell Armada 38x RTC driver");
+MODULE_AUTHOR("Gregory CLEMENT <gregory.clement@free-electrons.com>");
+MODULE_LICENSE("GPL");
+--- a/MAINTAINERS
+++ b/MAINTAINERS
+@@ -1136,6 +1136,7 @@ M:	Sebastian Hesselbarth <sebastian.hess
+ L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
+ S:	Maintained
+ F:	arch/arm/mach-mvebu/
+F:	drivers/rtc/armada38x-rtc
+ 
+ ARM/Marvell Berlin SoC support
+ M:	Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
+--- a/arch/arm/boot/dts/armada-38x.dtsi
+++ b/arch/arm/boot/dts/armada-38x.dtsi
+@@ -420,6 +420,13 @@
+ 				clocks = <&gateclk 4>;
+ 			};
+ 
+			rtc@a3800 {
+				compatible = "marvell,armada-380-rtc";
+				reg = <0xa3800 0x20>, <0x184a0 0x0c>;
+				reg-names = "rtc", "rtc-soc";
+				interrupts = <GIC_SPI 21 IRQ_TYPE_LEVEL_HIGH>;
+			};
+
+ 			sata@a8000 {
+ 				compatible = "marvell,armada-380-ahci";
+ 				reg = <0xa8000 0x2000>;