rtc: add Alphascale asm9260 driver

Add support for RTC controller found on Alphascale asm9260
SoC.

Signed-off-by: Oleksij Rempel <linux@rempel-privat.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

1 files changed, 355 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-asm9260.c b/drivers/rtc/rtc-asm9260.c
new file mode 100644
index 000000000000..14e08c4c1a01
--- /dev/null
+++ b/drivers/rtc/rtc-asm9260.c
@@ -0,0 +1,355 @@
+/*
+ * Copyright (C) 2016 Oleksij Rempel <linux@rempel-privat.de>
+ *
+ * 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/clk.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+
+/* Miscellaneous registers */
+/* Interrupt Location Register */
+#define HW_ILR			0x00
+#define BM_RTCALF		BIT(1)
+#define BM_RTCCIF		BIT(0)
+
+/* Clock Control Register */
+#define HW_CCR			0x08
+/* Calibration counter disable */
+#define BM_CCALOFF		BIT(4)
+/* Reset internal oscillator divider */
+#define BM_CTCRST		BIT(1)
+/* Clock Enable */
+#define BM_CLKEN		BIT(0)
+
+/* Counter Increment Interrupt Register */
+#define HW_CIIR			0x0C
+#define BM_CIIR_IMYEAR		BIT(7)
+#define BM_CIIR_IMMON		BIT(6)
+#define BM_CIIR_IMDOY		BIT(5)
+#define BM_CIIR_IMDOW		BIT(4)
+#define BM_CIIR_IMDOM		BIT(3)
+#define BM_CIIR_IMHOUR		BIT(2)
+#define BM_CIIR_IMMIN		BIT(1)
+#define BM_CIIR_IMSEC		BIT(0)
+
+/* Alarm Mask Register */
+#define HW_AMR			0x10
+#define BM_AMR_IMYEAR		BIT(7)
+#define BM_AMR_IMMON		BIT(6)
+#define BM_AMR_IMDOY		BIT(5)
+#define BM_AMR_IMDOW		BIT(4)
+#define BM_AMR_IMDOM		BIT(3)
+#define BM_AMR_IMHOUR		BIT(2)
+#define BM_AMR_IMMIN		BIT(1)
+#define BM_AMR_IMSEC		BIT(0)
+#define BM_AMR_OFF		0xff
+
+/* Consolidated time registers */
+#define HW_CTIME0		0x14
+#define BM_CTIME0_DOW_S		24
+#define BM_CTIME0_DOW_M		0x7
+#define BM_CTIME0_HOUR_S	16
+#define BM_CTIME0_HOUR_M	0x1f
+#define BM_CTIME0_MIN_S		8
+#define BM_CTIME0_MIN_M		0x3f
+#define BM_CTIME0_SEC_S		0
+#define BM_CTIME0_SEC_M		0x3f
+
+#define HW_CTIME1		0x18
+#define BM_CTIME1_YEAR_S	16
+#define BM_CTIME1_YEAR_M	0xfff
+#define BM_CTIME1_MON_S		8
+#define BM_CTIME1_MON_M		0xf
+#define BM_CTIME1_DOM_S		0
+#define BM_CTIME1_DOM_M		0x1f
+
+#define HW_CTIME2		0x1C
+#define BM_CTIME2_DOY_S		0
+#define BM_CTIME2_DOY_M		0xfff
+
+/* Time counter registers */
+#define HW_SEC			0x20
+#define HW_MIN			0x24
+#define HW_HOUR			0x28
+#define HW_DOM			0x2C
+#define HW_DOW			0x30
+#define HW_DOY			0x34
+#define HW_MONTH		0x38
+#define HW_YEAR			0x3C
+
+#define HW_CALIBRATION		0x40
+#define BM_CALDIR_BACK		BIT(17)
+#define BM_CALVAL_M		0x1ffff
+
+/* General purpose registers */
+#define HW_GPREG0		0x44
+#define HW_GPREG1		0x48
+#define HW_GPREG2		0x4C
+#define HW_GPREG3		0x50
+#define HW_GPREG4		0x54
+
+/* Alarm register group */
+#define HW_ALSEC		0x60
+#define HW_ALMIN		0x64
+#define HW_ALHOUR		0x68
+#define HW_ALDOM		0x6C
+#define HW_ALDOW		0x70
+#define HW_ALDOY		0x74
+#define HW_ALMON		0x78
+#define HW_ALYEAR		0x7C
+
+struct asm9260_rtc_priv {
+	struct device		*dev;
+	void __iomem		*iobase;
+	struct rtc_device	*rtc;
+	struct clk		*clk;
+	/* io lock */
+	spinlock_t		lock;
+};
+
+static irqreturn_t asm9260_rtc_irq(int irq, void *dev_id)
+{
+	struct asm9260_rtc_priv *priv = dev_id;
+	u32 isr;
+	unsigned long events = 0;
+
+	isr = ioread32(priv->iobase + HW_CIIR);
+	if (!isr)
+		return IRQ_NONE;
+
+	iowrite32(0, priv->iobase + HW_CIIR);
+
+	events |= RTC_AF | RTC_IRQF;
+
+	rtc_update_irq(priv->rtc, 1, events);
+
+	return IRQ_HANDLED;
+}
+
+static int asm9260_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);
+	u32 ctime0, ctime1, ctime2;
+	unsigned long irq_flags;
+
+	spin_lock_irqsave(&priv->lock, irq_flags);
+	ctime0 = ioread32(priv->iobase + HW_CTIME0);
+	ctime1 = ioread32(priv->iobase + HW_CTIME1);
+	ctime2 = ioread32(priv->iobase + HW_CTIME2);
+
+	if (ctime1 != ioread32(priv->iobase + HW_CTIME1)) {
+		/*
+		 * woops, counter flipped right now. Now we are safe
+		 * to reread.
+		 */
+		ctime0 = ioread32(priv->iobase + HW_CTIME0);
+		ctime1 = ioread32(priv->iobase + HW_CTIME1);
+		ctime2 = ioread32(priv->iobase + HW_CTIME2);
+	}
+	spin_unlock_irqrestore(&priv->lock, irq_flags);
+
+	tm->tm_sec  = (ctime0 >> BM_CTIME0_SEC_S)  & BM_CTIME0_SEC_M;
+	tm->tm_min  = (ctime0 >> BM_CTIME0_MIN_S)  & BM_CTIME0_MIN_M;
+	tm->tm_hour = (ctime0 >> BM_CTIME0_HOUR_S) & BM_CTIME0_HOUR_M;
+	tm->tm_wday = (ctime0 >> BM_CTIME0_DOW_S)  & BM_CTIME0_DOW_M;
+
+	tm->tm_mday = (ctime1 >> BM_CTIME1_DOM_S)  & BM_CTIME1_DOM_M;
+	tm->tm_mon  = (ctime1 >> BM_CTIME1_MON_S)  & BM_CTIME1_MON_M;
+	tm->tm_year = (ctime1 >> BM_CTIME1_YEAR_S) & BM_CTIME1_YEAR_M;
+
+	tm->tm_yday = (ctime2 >> BM_CTIME2_DOY_S)  & BM_CTIME2_DOY_M;
+
+	return 0;
+}
+
+static int asm9260_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);
+	unsigned long irq_flags;
+
+	spin_lock_irqsave(&priv->lock, irq_flags);
+	/*
+	 * make sure SEC counter will not flip other counter on write time,
+	 * real value will be written at the enf of sequence.
+	 */
+	iowrite32(0, priv->iobase + HW_SEC);
+
+	iowrite32(tm->tm_year, priv->iobase + HW_YEAR);
+	iowrite32(tm->tm_mon,  priv->iobase + HW_MONTH);
+	iowrite32(tm->tm_mday, priv->iobase + HW_DOM);
+	iowrite32(tm->tm_wday, priv->iobase + HW_DOW);
+	iowrite32(tm->tm_yday, priv->iobase + HW_DOY);
+	iowrite32(tm->tm_hour, priv->iobase + HW_HOUR);
+	iowrite32(tm->tm_min,  priv->iobase + HW_MIN);
+	iowrite32(tm->tm_sec,  priv->iobase + HW_SEC);
+	spin_unlock_irqrestore(&priv->lock, irq_flags);
+
+	return 0;
+}
+
+static int asm9260_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);
+	unsigned long irq_flags;
+
+	spin_lock_irqsave(&priv->lock, irq_flags);
+	alrm->time.tm_year = ioread32(priv->iobase + HW_ALYEAR);
+	alrm->time.tm_mon  = ioread32(priv->iobase + HW_ALMON);
+	alrm->time.tm_mday = ioread32(priv->iobase + HW_ALDOM);
+	alrm->time.tm_wday = ioread32(priv->iobase + HW_ALDOW);
+	alrm->time.tm_yday = ioread32(priv->iobase + HW_ALDOY);
+	alrm->time.tm_hour = ioread32(priv->iobase + HW_ALHOUR);
+	alrm->time.tm_min  = ioread32(priv->iobase + HW_ALMIN);
+	alrm->time.tm_sec  = ioread32(priv->iobase + HW_ALSEC);
+
+	alrm->enabled = ioread32(priv->iobase + HW_AMR) ? 1 : 0;
+	alrm->pending = ioread32(priv->iobase + HW_CIIR) ? 1 : 0;
+	spin_unlock_irqrestore(&priv->lock, irq_flags);
+
+	return rtc_valid_tm(&alrm->time);
+}
+
+static int asm9260_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);
+	unsigned long irq_flags;
+
+	spin_lock_irqsave(&priv->lock, irq_flags);
+	iowrite32(alrm->time.tm_year, priv->iobase + HW_ALYEAR);
+	iowrite32(alrm->time.tm_mon,  priv->iobase + HW_ALMON);
+	iowrite32(alrm->time.tm_mday, priv->iobase + HW_ALDOM);
+	iowrite32(alrm->time.tm_wday, priv->iobase + HW_ALDOW);
+	iowrite32(alrm->time.tm_yday, priv->iobase + HW_ALDOY);
+	iowrite32(alrm->time.tm_hour, priv->iobase + HW_ALHOUR);
+	iowrite32(alrm->time.tm_min,  priv->iobase + HW_ALMIN);
+	iowrite32(alrm->time.tm_sec,  priv->iobase + HW_ALSEC);
+
+	iowrite32(alrm->enabled ? 0 : BM_AMR_OFF, priv->iobase + HW_AMR);
+	spin_unlock_irqrestore(&priv->lock, irq_flags);
+
+	return 0;
+}
+
+static int asm9260_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+	struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);
+
+	iowrite32(enabled ? 0 : BM_AMR_OFF, priv->iobase + HW_AMR);
+	return 0;
+}
+
+static const struct rtc_class_ops asm9260_rtc_ops = {
+	.read_time		= asm9260_rtc_read_time,
+	.set_time		= asm9260_rtc_set_time,
+	.read_alarm		= asm9260_rtc_read_alarm,
+	.set_alarm		= asm9260_rtc_set_alarm,
+	.alarm_irq_enable	= asm9260_alarm_irq_enable,
+};
+
+static int __init asm9260_rtc_probe(struct platform_device *pdev)
+{
+	struct asm9260_rtc_priv *priv;
+	struct device *dev = &pdev->dev;
+	struct resource	*res;
+	int irq_alarm, ret;
+	u32 ccr;
+
+	priv = devm_kzalloc(dev, sizeof(struct asm9260_rtc_priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->dev = &pdev->dev;
+	platform_set_drvdata(pdev, priv);
+
+	irq_alarm = platform_get_irq(pdev, 0);
+	if (irq_alarm < 0) {
+		dev_err(dev, "No alarm IRQ resource defined\n");
+		return irq_alarm;
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	priv->iobase = devm_ioremap_resource(dev, res);
+	if (IS_ERR(priv->iobase))
+		return PTR_ERR(priv->iobase);
+
+	priv->clk = devm_clk_get(dev, "ahb");
+	ret = clk_prepare_enable(priv->clk);
+	if (ret) {
+		dev_err(dev, "Failed to enable clk!\n");
+		return ret;
+	}
+
+	ccr = ioread32(priv->iobase + HW_CCR);
+	/* if dev is not enabled, reset it */
+	if ((ccr & (BM_CLKEN | BM_CTCRST)) != BM_CLKEN) {
+		iowrite32(BM_CTCRST, priv->iobase + HW_CCR);
+		ccr = 0;
+	}
+
+	iowrite32(BM_CLKEN | ccr, priv->iobase + HW_CCR);
+	iowrite32(0, priv->iobase + HW_CIIR);
+	iowrite32(BM_AMR_OFF, priv->iobase + HW_AMR);
+
+	priv->rtc = devm_rtc_device_register(dev, dev_name(dev),
+					     &asm9260_rtc_ops, THIS_MODULE);
+	if (IS_ERR(priv->rtc)) {
+		ret = PTR_ERR(priv->rtc);
+		dev_err(dev, "Failed to register RTC device: %d\n", ret);
+		goto err_return;
+	}
+
+	ret = devm_request_threaded_irq(dev, irq_alarm, NULL,
+					asm9260_rtc_irq, IRQF_ONESHOT,
+					dev_name(dev), priv);
+	if (ret < 0) {
+		dev_err(dev, "can't get irq %i, err %d\n",
+			irq_alarm, ret);
+		goto err_return;
+	}
+
+	return 0;
+
+err_return:
+	clk_disable_unprepare(priv->clk);
+	return ret;
+}
+
+static int __exit asm9260_rtc_remove(struct platform_device *pdev)
+{
+	struct asm9260_rtc_priv *priv = platform_get_drvdata(pdev);
+
+	/* Disable alarm matching */
+	iowrite32(BM_AMR_OFF, priv->iobase + HW_AMR);
+	clk_disable_unprepare(priv->clk);
+	return 0;
+}
+
+static const struct of_device_id asm9260_dt_ids[] = {
+	{ .compatible = "alphascale,asm9260-rtc", },
+	{}
+};
+
+static struct platform_driver asm9260_rtc_driver = {
+	.probe		= asm9260_rtc_probe,
+	.remove		= asm9260_rtc_remove,
+	.driver		= {
+		.name	= "asm9260-rtc",
+		.owner	= THIS_MODULE,
+		.of_match_table = asm9260_dt_ids,
+	},
+};
+
+module_platform_driver(asm9260_rtc_driver);
+
+MODULE_AUTHOR("Oleksij Rempel <linux@rempel-privat.de>");
+MODULE_DESCRIPTION("Alphascale asm9260 SoC Realtime Clock Driver (RTC)");
+MODULE_LICENSE("GPL");