[PATCH 0/2] RTC support for NXP LPC18xx family

[PATCH 0/2] RTC support for NXP LPC18xx family

[Joachim Eastwood]

This patch set adds support for the RTC found on many NXP devices
including LPC24xx/178x/18xx/43xx. The RTC provides calendar and
clock functionality together with periodic tick and alarm interrupt
support.

The driver is a rework of an old driver by Kevin Wells. It has been
modified to support modern resource allocation, device tree and
generally cleaned up.

Patch set is based on Linux v4.1-rc1.

Base support for the NXP LPC18xx family can be found here:
http://marc.info/?l=linux-arm-kernel&m=143016894704253&w=2

Joachim Eastwood (2):
  rtc: add rtc-lpc24xx driver
  doc: dt: add documentation for nxp,lpc1788-rtc

 .../devicetree/bindings/rtc/nxp,lpc1788-rtc.txt    |  21 ++
 drivers/rtc/Kconfig                                |  11 +
 drivers/rtc/Makefile                               |   1 +
 drivers/rtc/rtc-lpc24xx.c                          | 379 +++++++++++++++++++++
 4 files changed, 412 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/rtc/nxp,lpc1788-rtc.txt
 create mode 100644 drivers/rtc/rtc-lpc24xx.c

-- 
1.8.0

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[PATCH 1/2] rtc: add rtc-lpc24xx driver

[Joachim Eastwood]

Add driver for the RTC found on NXP LPC24xx/178x/18xx/43xx devices.
The RTC provides calendar and clock functionality together with
periodic tick and alarm interrupt support.

Signed-off-by: Joachim Eastwood <manabian-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 drivers/rtc/Kconfig       |  11 ++
 drivers/rtc/Makefile      |   1 +
 drivers/rtc/rtc-lpc24xx.c | 379 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 391 insertions(+)
 create mode 100644 drivers/rtc/rtc-lpc24xx.c

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 6149ae01e11f..42b890716b1c 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -1427,6 +1427,17 @@ config RTC_DRV_JZ4740
 	  This driver can also be buillt as a module. If so, the module
 	  will be called rtc-jz4740.
 
+config RTC_DRV_LPC24XX
+	depends on OF && (ARCH_LPC18XX || TEST_COMPILE)
+	tristate "NXP LPC2K RTC"
+	help
+	  This enables support for the NXP RTC found which can be found on
+	  LPC24xx/178x/18xx/43xx devices.
+
+	  If you have one of the devices above enable this driver to use
+	  the hardware RTC. This driver can also be buillt as a module. If
+	  so, the module will be called rtc-lpc24xx.
+
 config RTC_DRV_LPC32XX
 	depends on ARCH_LPC32XX
 	tristate "NXP LPC32XX RTC"
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index c31731c29762..8687a2e13247 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -73,6 +73,7 @@ obj-$(CONFIG_RTC_DRV_ISL12022)	+= rtc-isl12022.o
 obj-$(CONFIG_RTC_DRV_ISL12057)	+= rtc-isl12057.o
 obj-$(CONFIG_RTC_DRV_JZ4740)	+= rtc-jz4740.o
 obj-$(CONFIG_RTC_DRV_LP8788)	+= rtc-lp8788.o
+obj-$(CONFIG_RTC_DRV_LPC24XX)	+= rtc-lpc24xx.o
 obj-$(CONFIG_RTC_DRV_LPC32XX)	+= rtc-lpc32xx.o
 obj-$(CONFIG_RTC_DRV_LOONGSON1)	+= rtc-ls1x.o
 obj-$(CONFIG_RTC_DRV_M41T80)	+= rtc-m41t80.o
diff --git a/drivers/rtc/rtc-lpc24xx.c b/drivers/rtc/rtc-lpc24xx.c
new file mode 100644
index 000000000000..ffa6e568b308
--- /dev/null
+++ b/drivers/rtc/rtc-lpc24xx.c
@@ -0,0 +1,379 @@
+/*
+ * Driver for NXP LPC24xx/178x/18xx/43xx Real-Time Clock (RTC)
+ *
+ * Copyright (C) 2011 NXP Semiconductors
+ * Copyright (C) 2015 Joachim Eastwood <manabian-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
+ *
+ * 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/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+
+/* LPC24xx RTC register offsets */
+#define LPC24XX_ILR		0x00
+#define LPC24XX_CTC		0x04
+#define LPC24XX_CCR		0x08
+#define LPC24XX_CIIR		0x0c
+#define LPC24XX_AMR		0x10
+#define LPC24XX_CTIME0		0x14
+#define LPC24XX_CTIME1		0x18
+#define LPC24XX_CTIME2		0x1c
+#define LPC24XX_SEC		0x20
+#define LPC24XX_MIN		0x24
+#define LPC24XX_HOUR		0x28
+#define LPC24XX_DOM		0x2c
+#define LPC24XX_DOW		0x30
+#define LPC24XX_DOY		0x34
+#define LPC24XX_MONTH		0x38
+#define LPC24XX_YEAR		0x3c
+#define LPC24XX_CISS		0x40 /* LPC24xx only */
+#define LPC178X_CALIBRATION	0x40 /* LPC178x and up */
+#define LPC24XX_ALSEC		0x60
+#define LPC24XX_ALMIN		0x64
+#define LPC24XX_ALHOUR		0x68
+#define LPC24XX_ALDOM		0x6c
+#define LPC24XX_ALDOW		0x70
+#define LPC24XX_ALDOY		0x74
+#define LPC24XX_ALMON		0x78
+#define LPC24XX_ALYEAR		0x7c
+#define LPC24XX_PREINT		0x80 /* LPC24xx only */
+#define LPC24XX_PREFRAC		0x84 /* LPC24xx only */
+
+#define LPC24XX_RTCCIF		BIT(0)
+#define LPC24XX_RTCALF		BIT(1)
+#define LPC24XX_RTSSF		BIT(2) /* LPC24xx only */
+
+#define LPC24XX_CLKEN		BIT(0)
+#define LPC24XX_CTCRST		BIT(1)
+#define LPC24XX_CLKSRC		BIT(4) /* LPC24xx only */
+#define LPC178X_CCALEN		BIT(4) /* LPC178x and up */
+
+#define LPC24XX_IMSEC		BIT(0)
+#define LPC24XX_IMMIN		BIT(1)
+#define LPC24XX_IMHOUR		BIT(2)
+#define LPC24XX_IMDOM		BIT(3)
+#define LPC24XX_IMDOW		BIT(4)
+#define LPC24XX_IMDOY		BIT(5)
+#define LPC24XX_IMMON		BIT(6)
+#define LPC24XX_IMYEAR		BIT(7)
+
+#define LPC24XX_ALARM_DISABLE	0xff
+
+#define CT0_SECS(x)		(((x) >> 0)  & 0x3f)
+#define CT0_MINS(x)		(((x) >> 8)  & 0x3f)
+#define CT0_HOURS(x)		(((x) >> 16) & 0x1f)
+#define CT0_DOW(x)		(((x) >> 24) & 0x07)
+#define CT1_DOM(x)		(((x) >> 0)  & 0x1f)
+#define CT1_MONTH(x)		(((x) >> 8)  & 0x0f)
+#define CT1_YEAR(x)		(((x) >> 16) & 0xfff)
+#define CT2_DOY(x)		(((x) >> 0)  & 0xfff)
+
+#define rtc_readl(dev, reg)		readl((dev)->rtc_base + (reg))
+#define rtc_writel(dev, reg, val)	writel((val), (dev)->rtc_base + (reg))
+
+/* lpc2k-rtc driver feature flags */
+#define HAVE_SUBSECOND		BIT(0)
+#define HAVE_CALIBRATION	BIT(1)
+#define HAVE_PRESCALER		BIT(2)
+
+struct lpc24xx_rtc {
+	void __iomem *rtc_base;
+	struct rtc_device *rtc;
+	struct clk *clk_rtc;
+	struct clk *clk_reg;
+	u32 features;
+};
+
+static int lpc24xx_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
+	u32 rtc_ctrl;
+
+	/* Disable RTC during update */
+	rtc_ctrl = rtc_readl(rtc, LPC24XX_CCR);
+	rtc_writel(rtc, LPC24XX_CCR, rtc_ctrl & ~LPC24XX_CLKEN);
+
+	rtc_writel(rtc, LPC24XX_SEC,	tm->tm_sec);
+	rtc_writel(rtc, LPC24XX_MIN,	tm->tm_min);
+	rtc_writel(rtc, LPC24XX_HOUR,	tm->tm_hour);
+	rtc_writel(rtc, LPC24XX_DOW,	tm->tm_wday);
+	rtc_writel(rtc, LPC24XX_DOM,	tm->tm_mday);
+	rtc_writel(rtc, LPC24XX_DOY,	tm->tm_yday);
+	rtc_writel(rtc, LPC24XX_MONTH,	tm->tm_mon);
+	rtc_writel(rtc, LPC24XX_YEAR,	tm->tm_year);
+
+	rtc_writel(rtc, LPC24XX_CCR, rtc_ctrl | LPC24XX_CLKEN);
+
+	return 0;
+}
+
+static int lpc24xx_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
+	u32 ct0, ct1, ct2;
+
+	ct0 = rtc_readl(rtc, LPC24XX_CTIME0);
+	ct1 = rtc_readl(rtc, LPC24XX_CTIME1);
+	ct2 = rtc_readl(rtc, LPC24XX_CTIME2);
+
+	tm->tm_sec  = CT0_SECS(ct0);
+	tm->tm_min  = CT0_MINS(ct0);
+	tm->tm_hour = CT0_HOURS(ct0);
+	tm->tm_wday = CT0_DOW(ct0);
+	tm->tm_mon  = CT1_MONTH(ct1);
+	tm->tm_mday = CT1_DOM(ct1);
+	tm->tm_year = CT1_YEAR(ct1);
+	tm->tm_yday = CT2_DOY(ct2);
+
+	if (rtc_valid_tm(tm) < 0) {
+		dev_warn(dev, "retrieved date and time is invalid\n");
+		rtc_time64_to_tm(0, tm);
+		lpc24xx_rtc_set_time(dev, tm);
+	}
+
+	return 0;
+}
+
+static int lpc24xx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
+{
+	struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
+	struct rtc_time *tm = &wkalrm->time;
+
+	tm->tm_sec  = rtc_readl(rtc, LPC24XX_ALSEC);
+	tm->tm_min  = rtc_readl(rtc, LPC24XX_ALMIN);
+	tm->tm_hour = rtc_readl(rtc, LPC24XX_ALHOUR);
+	tm->tm_mday = rtc_readl(rtc, LPC24XX_ALDOM);
+	tm->tm_wday = rtc_readl(rtc, LPC24XX_ALDOW);
+	tm->tm_yday = rtc_readl(rtc, LPC24XX_ALDOY);
+	tm->tm_mon  = rtc_readl(rtc, LPC24XX_ALMON);
+	tm->tm_year = rtc_readl(rtc, LPC24XX_ALYEAR);
+
+	wkalrm->enabled = rtc_readl(rtc, LPC24XX_AMR) == 0;
+	wkalrm->pending = !!(rtc_readl(rtc, LPC24XX_ILR) & LPC24XX_RTCCIF);
+
+	return rtc_valid_tm(&wkalrm->time);
+}
+
+static int lpc24xx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
+{
+	struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
+	struct rtc_time *tm = &wkalrm->time;
+
+	/* Disable alarm IRQs during update */
+	rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE);
+
+	rtc_writel(rtc, LPC24XX_ALSEC,  tm->tm_sec);
+	rtc_writel(rtc, LPC24XX_ALMIN,  tm->tm_min);
+	rtc_writel(rtc, LPC24XX_ALHOUR, tm->tm_hour);
+	rtc_writel(rtc, LPC24XX_ALDOM,  tm->tm_mday);
+	rtc_writel(rtc, LPC24XX_ALDOW,  tm->tm_wday);
+	rtc_writel(rtc, LPC24XX_ALDOY,  tm->tm_yday);
+	rtc_writel(rtc, LPC24XX_ALMON,  tm->tm_mon);
+	rtc_writel(rtc, LPC24XX_ALYEAR, tm->tm_year);
+
+	if (wkalrm->enabled)
+		rtc_writel(rtc, LPC24XX_AMR, 0);
+
+	return 0;
+}
+
+static int lpc24xx_rtc_alarm_irq_enable(struct device *dev,
+					unsigned int enabled)
+{
+	struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
+
+	if (enabled)
+		rtc_writel(rtc, LPC24XX_AMR, 0);
+	else
+		rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE);
+
+	return 0;
+}
+
+static irqreturn_t lpc24xx_rtc_interrupt(int irq, void *dev)
+{
+	unsigned long events = RTC_IRQF;
+	struct lpc24xx_rtc *rtc = dev;
+	u32 rtc_iir;
+
+	/* Check interrupt cause */
+	rtc_iir = rtc_readl(rtc, LPC24XX_ILR);
+
+	/* 1s tick */
+	if (rtc_iir & LPC24XX_RTCCIF)
+		events |= RTC_UF;
+
+	/* Alarm */
+	if (rtc_iir & LPC24XX_RTCALF) {
+		events |= RTC_AF;
+		rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE);
+	}
+
+	/* Clear interrupt status and report event */
+	rtc_writel(rtc, LPC24XX_ILR, rtc_iir);
+	rtc_update_irq(rtc->rtc, 1, events);
+
+	return IRQ_HANDLED;
+}
+
+static const struct rtc_class_ops lpc24xx_rtc_ops = {
+	.read_time		= lpc24xx_rtc_read_time,
+	.set_time		= lpc24xx_rtc_set_time,
+	.read_alarm		= lpc24xx_rtc_read_alarm,
+	.set_alarm		= lpc24xx_rtc_set_alarm,
+	.alarm_irq_enable	= lpc24xx_rtc_alarm_irq_enable,
+};
+
+static const struct of_device_id lpc24xx_rtc_match[] = {
+	{ .compatible = "nxp,lpc1788-rtc", .data = (void *)HAVE_CALIBRATION},
+	{ }
+};
+MODULE_DEVICE_TABLE(of, lpc24xx_rtc_match);
+
+static int lpc24xx_rtc_probe(struct platform_device *pdev)
+{
+	const struct of_device_id *match;
+	struct lpc24xx_rtc *rtc;
+	struct resource *res;
+	u32 rtc_ccr = 0;
+	int irq, ret;
+
+	match = of_match_device(lpc24xx_rtc_match, &pdev->dev);
+	if (!match) {
+		dev_err(&pdev->dev, "no device match found\n");
+		return -ENODEV;
+	}
+
+	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
+	if (!rtc)
+		return -ENOMEM;
+
+	rtc->features = (u32)match->data;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	rtc->rtc_base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(rtc->rtc_base))
+		return PTR_ERR(rtc->rtc_base);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_warn(&pdev->dev, "can't get interrupt resource\n");
+		return irq;
+	}
+
+	rtc->clk_rtc = devm_clk_get(&pdev->dev, "rtc");
+	if (IS_ERR(rtc->clk_rtc)) {
+		dev_err(&pdev->dev, "error getting rtc clock\n");
+		return PTR_ERR(rtc->clk_rtc);
+	}
+
+	rtc->clk_reg = devm_clk_get(&pdev->dev, "reg");
+	if (IS_ERR(rtc->clk_reg)) {
+		dev_err(&pdev->dev, "error getting reg clock\n");
+		return PTR_ERR(rtc->clk_reg);
+	}
+
+	ret = clk_prepare_enable(rtc->clk_rtc);
+	if (ret) {
+		dev_err(&pdev->dev, "unable to enable rtc clock\n");
+		return ret;
+	}
+
+	ret = clk_prepare_enable(rtc->clk_reg);
+	if (ret) {
+		dev_err(&pdev->dev, "unable to enable reg clock\n");
+		goto disable_rtc_clk;
+	}
+
+	platform_set_drvdata(pdev, rtc);
+
+	/* Clear the counter increment state */
+	rtc_writel(rtc, LPC24XX_ILR, LPC24XX_RTCCIF);
+
+	if (rtc->features & HAVE_PRESCALER) {
+		/* Clock source is 32k oscillator */
+		rtc_ccr = LPC24XX_CLKSRC;
+		rtc_writel(rtc, LPC24XX_CCR, rtc_ccr);
+
+		/* Set prescaler to divide by 1 */
+		rtc_writel(rtc, LPC24XX_PREINT, 0);
+		rtc_writel(rtc, LPC24XX_PREFRAC, 0);
+	}
+
+	if (rtc->features & HAVE_SUBSECOND) {
+		/* Disable sub-second interrupt */
+		rtc_writel(rtc, LPC24XX_CISS, 0);
+	}
+
+	/* Only 1-second interrupt will generate interrupt */
+	rtc_writel(rtc, LPC24XX_CIIR, LPC24XX_IMSEC);
+
+	/* Enable RTC count */
+	rtc_writel(rtc, LPC24XX_CCR, rtc_ccr | LPC24XX_CLKEN);
+
+	ret = devm_request_irq(&pdev->dev, irq, lpc24xx_rtc_interrupt, 0,
+			       pdev->name, rtc);
+	if (ret < 0) {
+		dev_warn(&pdev->dev, "can't request interrupt\n");
+		goto disable_clks;
+	}
+
+	rtc->rtc = devm_rtc_device_register(&pdev->dev, "lpc2k-rtc",
+					    &lpc24xx_rtc_ops, THIS_MODULE);
+	if (IS_ERR(rtc->rtc)) {
+		dev_err(&pdev->dev, "can't register rtc device\n");
+		ret = PTR_ERR(rtc->rtc);
+		goto disable_clks;
+	}
+
+	return 0;
+
+disable_clks:
+	clk_disable_unprepare(rtc->clk_reg);
+disable_rtc_clk:
+	clk_disable_unprepare(rtc->clk_rtc);
+	return ret;
+}
+
+static int lpc24xx_rtc_remove(struct platform_device *pdev)
+{
+	struct lpc24xx_rtc *rtc = platform_get_drvdata(pdev);
+
+	/*
+	 * Disable alarm, but leave RTC enabled so it
+	 * remains valid across reset cycles.
+	 */
+	rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE);
+	rtc_writel(rtc, LPC24XX_CCR, 0);
+
+	clk_disable_unprepare(rtc->clk_rtc);
+	clk_disable_unprepare(rtc->clk_reg);
+
+	return 0;
+}
+
+static struct platform_driver lpc24xx_rtc_driver = {
+	.probe	= lpc24xx_rtc_probe,
+	.remove	= lpc24xx_rtc_remove,
+	.driver	= {
+		.name = "lpc2k-rtc",
+		.of_match_table	= lpc24xx_rtc_match,
+	},
+};
+module_platform_driver(lpc24xx_rtc_driver);
+
+MODULE_AUTHOR("Kevin Wells <wellsk40-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org");
+MODULE_DESCRIPTION("RTC driver for the LPC24xx SoC");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:lpc2k-rtc");
-- 
1.8.0

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Re: [PATCH 1/2] rtc: add rtc-lpc24xx driver

[Josh Cartwright]

[-- Attachment #1: Type: text/plain, Size: 1590 bytes --]

Hello Joachim,

Just a quick comment/question below.

On Thu, May 14, 2015 at 07:34:34PM +0200, Joachim Eastwood wrote:
> Add driver for the RTC found on NXP LPC24xx/178x/18xx/43xx devices.
> The RTC provides calendar and clock functionality together with
> periodic tick and alarm interrupt support.
> 
> Signed-off-by: Joachim Eastwood <manabian-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> ---
[..]
> +
> +static const struct of_device_id lpc24xx_rtc_match[] = {
> +	{ .compatible = "nxp,lpc1788-rtc", .data = (void *)HAVE_CALIBRATION},
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, lpc24xx_rtc_match);
> +
> +static int lpc24xx_rtc_probe(struct platform_device *pdev)
> +{
> +	const struct of_device_id *match;
> +	struct lpc24xx_rtc *rtc;
> +	struct resource *res;
> +	u32 rtc_ccr = 0;
> +	int irq, ret;
> +
[..]
> +
> +	/* Clear the counter increment state */
> +	rtc_writel(rtc, LPC24XX_ILR, LPC24XX_RTCCIF);
> +
> +	if (rtc->features & HAVE_PRESCALER) {
> +		/* Clock source is 32k oscillator */
> +		rtc_ccr = LPC24XX_CLKSRC;
> +		rtc_writel(rtc, LPC24XX_CCR, rtc_ccr);
> +
> +		/* Set prescaler to divide by 1 */
> +		rtc_writel(rtc, LPC24XX_PREINT, 0);
> +		rtc_writel(rtc, LPC24XX_PREFRAC, 0);
> +	}
> +
> +	if (rtc->features & HAVE_SUBSECOND) {
> +		/* Disable sub-second interrupt */
> +		rtc_writel(rtc, LPC24XX_CISS, 0);
> +	}

Neither HAVE_PRESCALER, nor HAVE_SUBSECOND are used for the claimed
supported RTC, so this is effectively dead code.  Was this something you
intended to add later?  Some remnant of the rework?

  Josh

[-- Attachment #2: Type: application/pgp-signature, Size: 473 bytes --]

Re: [PATCH 1/2] rtc: add rtc-lpc24xx driver

[Joachim Eastwood]

On 14 May 2015 at 20:19, Josh Cartwright <joshc-acOepvfBmUk@public.gmane.org> wrote:
> Hello Joachim,
>
> Just a quick comment/question below.
>
> On Thu, May 14, 2015 at 07:34:34PM +0200, Joachim Eastwood wrote:
>> Add driver for the RTC found on NXP LPC24xx/178x/18xx/43xx devices.
>> The RTC provides calendar and clock functionality together with
>> periodic tick and alarm interrupt support.
>>
>> Signed-off-by: Joachim Eastwood <manabian-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
>> ---
> [..]
>> +
>> +static const struct of_device_id lpc24xx_rtc_match[] = {
>> +     { .compatible = "nxp,lpc1788-rtc", .data = (void *)HAVE_CALIBRATION},
>> +     { }
>> +};
>> +MODULE_DEVICE_TABLE(of, lpc24xx_rtc_match);
>> +
>> +static int lpc24xx_rtc_probe(struct platform_device *pdev)
>> +{
>> +     const struct of_device_id *match;
>> +     struct lpc24xx_rtc *rtc;
>> +     struct resource *res;
>> +     u32 rtc_ccr = 0;
>> +     int irq, ret;
>> +
> [..]
>> +
>> +     /* Clear the counter increment state */
>> +     rtc_writel(rtc, LPC24XX_ILR, LPC24XX_RTCCIF);
>> +
>> +     if (rtc->features & HAVE_PRESCALER) {
>> +             /* Clock source is 32k oscillator */
>> +             rtc_ccr = LPC24XX_CLKSRC;
>> +             rtc_writel(rtc, LPC24XX_CCR, rtc_ccr);
>> +
>> +             /* Set prescaler to divide by 1 */
>> +             rtc_writel(rtc, LPC24XX_PREINT, 0);
>> +             rtc_writel(rtc, LPC24XX_PREFRAC, 0);
>> +     }
>> +
>> +     if (rtc->features & HAVE_SUBSECOND) {
>> +             /* Disable sub-second interrupt */
>> +             rtc_writel(rtc, LPC24XX_CISS, 0);
>> +     }
>
> Neither HAVE_PRESCALER, nor HAVE_SUBSECOND are used for the claimed
> supported RTC, so this is effectively dead code.  Was this something you
> intended to add later?  Some remnant of the rework?

The features are only available on the old LPC24xx-series which isn't
in mainline so, yeah, this can be removed. I'll send out a new version
in a couple of days removing all of the LPC24xx support.

Thanks for looking.

regards,
Joachim Eastwood
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Re: [rtc-linux] [PATCH 1/2] rtc: add rtc-lpc24xx driver

[Alexandre Belloni]

Hi,

On 14/05/2015 at 19:34:34 +0200, Joachim Eastwood wrote :
> Add driver for the RTC found on NXP LPC24xx/178x/18xx/43xx devices.
> The RTC provides calendar and clock functionality together with
> periodic tick and alarm interrupt support.
> 
> Signed-off-by: Joachim Eastwood <manabian-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> ---
>  drivers/rtc/Kconfig       |  11 ++
>  drivers/rtc/Makefile      |   1 +
>  drivers/rtc/rtc-lpc24xx.c | 379 ++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 391 insertions(+)
>  create mode 100644 drivers/rtc/rtc-lpc24xx.c
> 
> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
> index 6149ae01e11f..42b890716b1c 100644
> --- a/drivers/rtc/Kconfig
> +++ b/drivers/rtc/Kconfig
> @@ -1427,6 +1427,17 @@ config RTC_DRV_JZ4740
>  	  This driver can also be buillt as a module. If so, the module
>  	  will be called rtc-jz4740.
>  
> +config RTC_DRV_LPC24XX
> +	depends on OF && (ARCH_LPC18XX || TEST_COMPILE)

You probably meant COMPILE_TEST and it probably needs to depend on
HAS_IOMEM

> +	tristate "NXP LPC2K RTC"

I'm not sure about LPC2K, you use LPC24XX for the config symbol and the
filename also, just below the string is LPC32XX. But maybe that is fine
if this is the most commonly used denomination.

> +	help
> +	  This enables support for the NXP RTC found which can be found on
> +	  LPC24xx/178x/18xx/43xx devices.
> +
> +	  If you have one of the devices above enable this driver to use
> +	  the hardware RTC. This driver can also be buillt as a module. If
> +	  so, the module will be called rtc-lpc24xx.
> +
>  config RTC_DRV_LPC32XX
>  	depends on ARCH_LPC32XX
>  	tristate "NXP LPC32XX RTC"
> diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
> index c31731c29762..8687a2e13247 100644
> --- a/drivers/rtc/Makefile
> +++ b/drivers/rtc/Makefile
> @@ -73,6 +73,7 @@ obj-$(CONFIG_RTC_DRV_ISL12022)	+= rtc-isl12022.o
>  obj-$(CONFIG_RTC_DRV_ISL12057)	+= rtc-isl12057.o
>  obj-$(CONFIG_RTC_DRV_JZ4740)	+= rtc-jz4740.o
>  obj-$(CONFIG_RTC_DRV_LP8788)	+= rtc-lp8788.o
> +obj-$(CONFIG_RTC_DRV_LPC24XX)	+= rtc-lpc24xx.o
>  obj-$(CONFIG_RTC_DRV_LPC32XX)	+= rtc-lpc32xx.o
>  obj-$(CONFIG_RTC_DRV_LOONGSON1)	+= rtc-ls1x.o
>  obj-$(CONFIG_RTC_DRV_M41T80)	+= rtc-m41t80.o
> diff --git a/drivers/rtc/rtc-lpc24xx.c b/drivers/rtc/rtc-lpc24xx.c
> new file mode 100644
> index 000000000000..ffa6e568b308
> --- /dev/null
> +++ b/drivers/rtc/rtc-lpc24xx.c
> @@ -0,0 +1,379 @@
> +/*
> + * Driver for NXP LPC24xx/178x/18xx/43xx Real-Time Clock (RTC)
> + *
> + * Copyright (C) 2011 NXP Semiconductors
> + * Copyright (C) 2015 Joachim Eastwood <manabian-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> + *
> + * 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/io.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/rtc.h>
> +
> +/* LPC24xx RTC register offsets */
> +#define LPC24XX_ILR		0x00
> +#define LPC24XX_CTC		0x04
> +#define LPC24XX_CCR		0x08
> +#define LPC24XX_CIIR		0x0c
> +#define LPC24XX_AMR		0x10
> +#define LPC24XX_CTIME0		0x14
> +#define LPC24XX_CTIME1		0x18
> +#define LPC24XX_CTIME2		0x1c
> +#define LPC24XX_SEC		0x20
> +#define LPC24XX_MIN		0x24
> +#define LPC24XX_HOUR		0x28
> +#define LPC24XX_DOM		0x2c
> +#define LPC24XX_DOW		0x30
> +#define LPC24XX_DOY		0x34
> +#define LPC24XX_MONTH		0x38
> +#define LPC24XX_YEAR		0x3c
> +#define LPC24XX_CISS		0x40 /* LPC24xx only */
> +#define LPC178X_CALIBRATION	0x40 /* LPC178x and up */
> +#define LPC24XX_ALSEC		0x60
> +#define LPC24XX_ALMIN		0x64
> +#define LPC24XX_ALHOUR		0x68
> +#define LPC24XX_ALDOM		0x6c
> +#define LPC24XX_ALDOW		0x70
> +#define LPC24XX_ALDOY		0x74
> +#define LPC24XX_ALMON		0x78
> +#define LPC24XX_ALYEAR		0x7c
> +#define LPC24XX_PREINT		0x80 /* LPC24xx only */
> +#define LPC24XX_PREFRAC		0x84 /* LPC24xx only */
> +
> +#define LPC24XX_RTCCIF		BIT(0)
> +#define LPC24XX_RTCALF		BIT(1)
> +#define LPC24XX_RTSSF		BIT(2) /* LPC24xx only */
> +
> +#define LPC24XX_CLKEN		BIT(0)
> +#define LPC24XX_CTCRST		BIT(1)
> +#define LPC24XX_CLKSRC		BIT(4) /* LPC24xx only */
> +#define LPC178X_CCALEN		BIT(4) /* LPC178x and up */
> +
> +#define LPC24XX_IMSEC		BIT(0)
> +#define LPC24XX_IMMIN		BIT(1)
> +#define LPC24XX_IMHOUR		BIT(2)
> +#define LPC24XX_IMDOM		BIT(3)
> +#define LPC24XX_IMDOW		BIT(4)
> +#define LPC24XX_IMDOY		BIT(5)
> +#define LPC24XX_IMMON		BIT(6)
> +#define LPC24XX_IMYEAR		BIT(7)
> +
> +#define LPC24XX_ALARM_DISABLE	0xff
> +
> +#define CT0_SECS(x)		(((x) >> 0)  & 0x3f)
> +#define CT0_MINS(x)		(((x) >> 8)  & 0x3f)
> +#define CT0_HOURS(x)		(((x) >> 16) & 0x1f)
> +#define CT0_DOW(x)		(((x) >> 24) & 0x07)
> +#define CT1_DOM(x)		(((x) >> 0)  & 0x1f)
> +#define CT1_MONTH(x)		(((x) >> 8)  & 0x0f)
> +#define CT1_YEAR(x)		(((x) >> 16) & 0xfff)
> +#define CT2_DOY(x)		(((x) >> 0)  & 0xfff)
> +
> +#define rtc_readl(dev, reg)		readl((dev)->rtc_base + (reg))
> +#define rtc_writel(dev, reg, val)	writel((val), (dev)->rtc_base + (reg))
> +
> +/* lpc2k-rtc driver feature flags */
> +#define HAVE_SUBSECOND		BIT(0)
> +#define HAVE_CALIBRATION	BIT(1)
> +#define HAVE_PRESCALER		BIT(2)
> +
> +struct lpc24xx_rtc {
> +	void __iomem *rtc_base;
> +	struct rtc_device *rtc;
> +	struct clk *clk_rtc;
> +	struct clk *clk_reg;
> +	u32 features;
> +};
> +
> +static int lpc24xx_rtc_set_time(struct device *dev, struct rtc_time *tm)
> +{
> +	struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
> +	u32 rtc_ctrl;
> +
> +	/* Disable RTC during update */
> +	rtc_ctrl = rtc_readl(rtc, LPC24XX_CCR);
> +	rtc_writel(rtc, LPC24XX_CCR, rtc_ctrl & ~LPC24XX_CLKEN);
> +
> +	rtc_writel(rtc, LPC24XX_SEC,	tm->tm_sec);
> +	rtc_writel(rtc, LPC24XX_MIN,	tm->tm_min);
> +	rtc_writel(rtc, LPC24XX_HOUR,	tm->tm_hour);
> +	rtc_writel(rtc, LPC24XX_DOW,	tm->tm_wday);
> +	rtc_writel(rtc, LPC24XX_DOM,	tm->tm_mday);
> +	rtc_writel(rtc, LPC24XX_DOY,	tm->tm_yday);
> +	rtc_writel(rtc, LPC24XX_MONTH,	tm->tm_mon);
> +	rtc_writel(rtc, LPC24XX_YEAR,	tm->tm_year);
> +
> +	rtc_writel(rtc, LPC24XX_CCR, rtc_ctrl | LPC24XX_CLKEN);
> +
> +	return 0;
> +}
> +
> +static int lpc24xx_rtc_read_time(struct device *dev, struct rtc_time *tm)
> +{
> +	struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
> +	u32 ct0, ct1, ct2;
> +
> +	ct0 = rtc_readl(rtc, LPC24XX_CTIME0);
> +	ct1 = rtc_readl(rtc, LPC24XX_CTIME1);
> +	ct2 = rtc_readl(rtc, LPC24XX_CTIME2);
> +
> +	tm->tm_sec  = CT0_SECS(ct0);
> +	tm->tm_min  = CT0_MINS(ct0);
> +	tm->tm_hour = CT0_HOURS(ct0);
> +	tm->tm_wday = CT0_DOW(ct0);
> +	tm->tm_mon  = CT1_MONTH(ct1);
> +	tm->tm_mday = CT1_DOM(ct1);
> +	tm->tm_year = CT1_YEAR(ct1);
> +	tm->tm_yday = CT2_DOY(ct2);
> +
> +	if (rtc_valid_tm(tm) < 0) {
> +		dev_warn(dev, "retrieved date and time is invalid\n");
> +		rtc_time64_to_tm(0, tm);
> +		lpc24xx_rtc_set_time(dev, tm);
> +	}
> +
> +	return 0;
> +}
> +
> +static int lpc24xx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
> +{
> +	struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
> +	struct rtc_time *tm = &wkalrm->time;
> +
> +	tm->tm_sec  = rtc_readl(rtc, LPC24XX_ALSEC);
> +	tm->tm_min  = rtc_readl(rtc, LPC24XX_ALMIN);
> +	tm->tm_hour = rtc_readl(rtc, LPC24XX_ALHOUR);
> +	tm->tm_mday = rtc_readl(rtc, LPC24XX_ALDOM);
> +	tm->tm_wday = rtc_readl(rtc, LPC24XX_ALDOW);
> +	tm->tm_yday = rtc_readl(rtc, LPC24XX_ALDOY);
> +	tm->tm_mon  = rtc_readl(rtc, LPC24XX_ALMON);
> +	tm->tm_year = rtc_readl(rtc, LPC24XX_ALYEAR);
> +
> +	wkalrm->enabled = rtc_readl(rtc, LPC24XX_AMR) == 0;
> +	wkalrm->pending = !!(rtc_readl(rtc, LPC24XX_ILR) & LPC24XX_RTCCIF);
> +
> +	return rtc_valid_tm(&wkalrm->time);
> +}
> +
> +static int lpc24xx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
> +{
> +	struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
> +	struct rtc_time *tm = &wkalrm->time;
> +
> +	/* Disable alarm IRQs during update */
> +	rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE);
> +
> +	rtc_writel(rtc, LPC24XX_ALSEC,  tm->tm_sec);
> +	rtc_writel(rtc, LPC24XX_ALMIN,  tm->tm_min);
> +	rtc_writel(rtc, LPC24XX_ALHOUR, tm->tm_hour);
> +	rtc_writel(rtc, LPC24XX_ALDOM,  tm->tm_mday);
> +	rtc_writel(rtc, LPC24XX_ALDOW,  tm->tm_wday);
> +	rtc_writel(rtc, LPC24XX_ALDOY,  tm->tm_yday);
> +	rtc_writel(rtc, LPC24XX_ALMON,  tm->tm_mon);
> +	rtc_writel(rtc, LPC24XX_ALYEAR, tm->tm_year);
> +
> +	if (wkalrm->enabled)
> +		rtc_writel(rtc, LPC24XX_AMR, 0);
> +
> +	return 0;
> +}
> +
> +static int lpc24xx_rtc_alarm_irq_enable(struct device *dev,
> +					unsigned int enabled)
> +{
> +	struct lpc24xx_rtc *rtc = dev_get_drvdata(dev);
> +
> +	if (enabled)
> +		rtc_writel(rtc, LPC24XX_AMR, 0);
> +	else
> +		rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE);
> +
> +	return 0;
> +}
> +
> +static irqreturn_t lpc24xx_rtc_interrupt(int irq, void *dev)
> +{
> +	unsigned long events = RTC_IRQF;
> +	struct lpc24xx_rtc *rtc = dev;
> +	u32 rtc_iir;
> +
> +	/* Check interrupt cause */
> +	rtc_iir = rtc_readl(rtc, LPC24XX_ILR);
> +
> +	/* 1s tick */
> +	if (rtc_iir & LPC24XX_RTCCIF)
> +		events |= RTC_UF;
> +
> +	/* Alarm */
> +	if (rtc_iir & LPC24XX_RTCALF) {
> +		events |= RTC_AF;
> +		rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE);
> +	}
> +
> +	/* Clear interrupt status and report event */
> +	rtc_writel(rtc, LPC24XX_ILR, rtc_iir);
> +	rtc_update_irq(rtc->rtc, 1, events);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static const struct rtc_class_ops lpc24xx_rtc_ops = {
> +	.read_time		= lpc24xx_rtc_read_time,
> +	.set_time		= lpc24xx_rtc_set_time,
> +	.read_alarm		= lpc24xx_rtc_read_alarm,
> +	.set_alarm		= lpc24xx_rtc_set_alarm,
> +	.alarm_irq_enable	= lpc24xx_rtc_alarm_irq_enable,
> +};
> +
> +static const struct of_device_id lpc24xx_rtc_match[] = {
> +	{ .compatible = "nxp,lpc1788-rtc", .data = (void *)HAVE_CALIBRATION},
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, lpc24xx_rtc_match);
> +
> +static int lpc24xx_rtc_probe(struct platform_device *pdev)
> +{
> +	const struct of_device_id *match;
> +	struct lpc24xx_rtc *rtc;
> +	struct resource *res;
> +	u32 rtc_ccr = 0;
> +	int irq, ret;
> +
> +	match = of_match_device(lpc24xx_rtc_match, &pdev->dev);
> +	if (!match) {

Because you are only using DT, this will never happen. Else the
lpc24xx_rtc_probe would not be called

> +		dev_err(&pdev->dev, "no device match found\n");
> +		return -ENODEV;
> +	}
> +
> +	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
> +	if (!rtc)
> +		return -ENOMEM;
> +
> +	rtc->features = (u32)match->data;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	rtc->rtc_base = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(rtc->rtc_base))
> +		return PTR_ERR(rtc->rtc_base);
> +
> +	irq = platform_get_irq(pdev, 0);
> +	if (irq < 0) {
> +		dev_warn(&pdev->dev, "can't get interrupt resource\n");
> +		return irq;
> +	}
> +
> +	rtc->clk_rtc = devm_clk_get(&pdev->dev, "rtc");
> +	if (IS_ERR(rtc->clk_rtc)) {
> +		dev_err(&pdev->dev, "error getting rtc clock\n");
> +		return PTR_ERR(rtc->clk_rtc);
> +	}
> +
> +	rtc->clk_reg = devm_clk_get(&pdev->dev, "reg");
> +	if (IS_ERR(rtc->clk_reg)) {
> +		dev_err(&pdev->dev, "error getting reg clock\n");
> +		return PTR_ERR(rtc->clk_reg);
> +	}
> +
> +	ret = clk_prepare_enable(rtc->clk_rtc);
> +	if (ret) {
> +		dev_err(&pdev->dev, "unable to enable rtc clock\n");
> +		return ret;
> +	}
> +
> +	ret = clk_prepare_enable(rtc->clk_reg);
> +	if (ret) {
> +		dev_err(&pdev->dev, "unable to enable reg clock\n");
> +		goto disable_rtc_clk;
> +	}
> +
> +	platform_set_drvdata(pdev, rtc);
> +
> +	/* Clear the counter increment state */
> +	rtc_writel(rtc, LPC24XX_ILR, LPC24XX_RTCCIF);
> +
> +	if (rtc->features & HAVE_PRESCALER) {
> +		/* Clock source is 32k oscillator */
> +		rtc_ccr = LPC24XX_CLKSRC;
> +		rtc_writel(rtc, LPC24XX_CCR, rtc_ccr);
> +
> +		/* Set prescaler to divide by 1 */
> +		rtc_writel(rtc, LPC24XX_PREINT, 0);
> +		rtc_writel(rtc, LPC24XX_PREFRAC, 0);
> +	}
> +
> +	if (rtc->features & HAVE_SUBSECOND) {
> +		/* Disable sub-second interrupt */
> +		rtc_writel(rtc, LPC24XX_CISS, 0);
> +	}
> +
> +	/* Only 1-second interrupt will generate interrupt */
> +	rtc_writel(rtc, LPC24XX_CIIR, LPC24XX_IMSEC);
> +
> +	/* Enable RTC count */
> +	rtc_writel(rtc, LPC24XX_CCR, rtc_ccr | LPC24XX_CLKEN);
> +
> +	ret = devm_request_irq(&pdev->dev, irq, lpc24xx_rtc_interrupt, 0,
> +			       pdev->name, rtc);
> +	if (ret < 0) {
> +		dev_warn(&pdev->dev, "can't request interrupt\n");
> +		goto disable_clks;
> +	}
> +
> +	rtc->rtc = devm_rtc_device_register(&pdev->dev, "lpc2k-rtc",

Same comment regarding the lpc2k name, also applies below.

> +					    &lpc24xx_rtc_ops, THIS_MODULE);
> +	if (IS_ERR(rtc->rtc)) {
> +		dev_err(&pdev->dev, "can't register rtc device\n");
> +		ret = PTR_ERR(rtc->rtc);
> +		goto disable_clks;
> +	}
> +
> +	return 0;
> +
> +disable_clks:
> +	clk_disable_unprepare(rtc->clk_reg);
> +disable_rtc_clk:
> +	clk_disable_unprepare(rtc->clk_rtc);
> +	return ret;
> +}
> +
> +static int lpc24xx_rtc_remove(struct platform_device *pdev)
> +{
> +	struct lpc24xx_rtc *rtc = platform_get_drvdata(pdev);
> +
> +	/*
> +	 * Disable alarm, but leave RTC enabled so it
> +	 * remains valid across reset cycles.
> +	 */
> +	rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE);
> +	rtc_writel(rtc, LPC24XX_CCR, 0);
> +
> +	clk_disable_unprepare(rtc->clk_rtc);
> +	clk_disable_unprepare(rtc->clk_reg);
> +
> +	return 0;
> +}
> +
> +static struct platform_driver lpc24xx_rtc_driver = {
> +	.probe	= lpc24xx_rtc_probe,
> +	.remove	= lpc24xx_rtc_remove,
> +	.driver	= {
> +		.name = "lpc2k-rtc",
> +		.of_match_table	= lpc24xx_rtc_match,
> +	},
> +};
> +module_platform_driver(lpc24xx_rtc_driver);
> +
> +MODULE_AUTHOR("Kevin Wells <wellsk40-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org");
> +MODULE_DESCRIPTION("RTC driver for the LPC24xx SoC");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:lpc2k-rtc");

-- 
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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Re: [rtc-linux] [PATCH 1/2] rtc: add rtc-lpc24xx driver

[Joachim Eastwood]

On 15 May 2015 at 00:15, Alexandre Belloni
<alexandre.belloni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org> wrote:
> Hi,
>
> On 14/05/2015 at 19:34:34 +0200, Joachim Eastwood wrote :
>> Add driver for the RTC found on NXP LPC24xx/178x/18xx/43xx devices.
>> The RTC provides calendar and clock functionality together with
>> periodic tick and alarm interrupt support.
>>
>> Signed-off-by: Joachim Eastwood <manabian-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
>> ---
>>  drivers/rtc/Kconfig       |  11 ++
>>  drivers/rtc/Makefile      |   1 +
>>  drivers/rtc/rtc-lpc24xx.c | 379 ++++++++++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 391 insertions(+)
>>  create mode 100644 drivers/rtc/rtc-lpc24xx.c
>>
>> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
>> index 6149ae01e11f..42b890716b1c 100644
>> --- a/drivers/rtc/Kconfig
>> +++ b/drivers/rtc/Kconfig
>> @@ -1427,6 +1427,17 @@ config RTC_DRV_JZ4740
>>         This driver can also be buillt as a module. If so, the module
>>         will be called rtc-jz4740.
>>
>> +config RTC_DRV_LPC24XX
>> +     depends on OF && (ARCH_LPC18XX || TEST_COMPILE)
>
> You probably meant COMPILE_TEST

ops, yes :)

>and it probably needs to depend on HAS_IOMEM

Indeed.

>> +     tristate "NXP LPC2K RTC"
>
> I'm not sure about LPC2K, you use LPC24XX for the config symbol and the
> filename also, just below the string is LPC32XX. But maybe that is fine
> if this is the most commonly used denomination.

I left the name used in the original driver. But I agree, using
LPC24XX everywhere would be more consistent. I'll change it in the
next version.

>> +     help
>> +       This enables support for the NXP RTC found which can be found on
>> +       LPC24xx/178x/18xx/43xx devices.
>> +
>> +       If you have one of the devices above enable this driver to use
>> +       the hardware RTC. This driver can also be buillt as a module. If
>> +       so, the module will be called rtc-lpc24xx.
>> +
>>  config RTC_DRV_LPC32XX
>>       depends on ARCH_LPC32XX
>>       tristate "NXP LPC32XX RTC"

<snip>

>> +static int lpc24xx_rtc_probe(struct platform_device *pdev)
>> +{
>> +     const struct of_device_id *match;
>> +     struct lpc24xx_rtc *rtc;
>> +     struct resource *res;
>> +     u32 rtc_ccr = 0;
>> +     int irq, ret;
>> +
>> +     match = of_match_device(lpc24xx_rtc_match, &pdev->dev);
>> +     if (!match) {
>
> Because you are only using DT, this will never happen. Else the
> lpc24xx_rtc_probe would not be called

This will go away in the next version since I'll be removing support
for the older versions of this ip block and thus no need for the match
data.

>> +             dev_err(&pdev->dev, "no device match found\n");
>> +             return -ENODEV;
>> +     }
>> +
>> +     rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
>> +     if (!rtc)
>> +             return -ENOMEM;
>> +
>> +     rtc->features = (u32)match->data;
>> +
>> +     res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> +     rtc->rtc_base = devm_ioremap_resource(&pdev->dev, res);
>> +     if (IS_ERR(rtc->rtc_base))
>> +             return PTR_ERR(rtc->rtc_base);
>> +
>> +     irq = platform_get_irq(pdev, 0);
>> +     if (irq < 0) {
>> +             dev_warn(&pdev->dev, "can't get interrupt resource\n");
>> +             return irq;
>> +     }
>> +
>> +     rtc->clk_rtc = devm_clk_get(&pdev->dev, "rtc");
>> +     if (IS_ERR(rtc->clk_rtc)) {
>> +             dev_err(&pdev->dev, "error getting rtc clock\n");
>> +             return PTR_ERR(rtc->clk_rtc);
>> +     }
>> +
>> +     rtc->clk_reg = devm_clk_get(&pdev->dev, "reg");
>> +     if (IS_ERR(rtc->clk_reg)) {
>> +             dev_err(&pdev->dev, "error getting reg clock\n");
>> +             return PTR_ERR(rtc->clk_reg);
>> +     }
>> +
>> +     ret = clk_prepare_enable(rtc->clk_rtc);
>> +     if (ret) {
>> +             dev_err(&pdev->dev, "unable to enable rtc clock\n");
>> +             return ret;
>> +     }
>> +
>> +     ret = clk_prepare_enable(rtc->clk_reg);
>> +     if (ret) {
>> +             dev_err(&pdev->dev, "unable to enable reg clock\n");
>> +             goto disable_rtc_clk;
>> +     }
>> +
>> +     platform_set_drvdata(pdev, rtc);
>> +
>> +     /* Clear the counter increment state */
>> +     rtc_writel(rtc, LPC24XX_ILR, LPC24XX_RTCCIF);
>> +
>> +     if (rtc->features & HAVE_PRESCALER) {
>> +             /* Clock source is 32k oscillator */
>> +             rtc_ccr = LPC24XX_CLKSRC;
>> +             rtc_writel(rtc, LPC24XX_CCR, rtc_ccr);
>> +
>> +             /* Set prescaler to divide by 1 */
>> +             rtc_writel(rtc, LPC24XX_PREINT, 0);
>> +             rtc_writel(rtc, LPC24XX_PREFRAC, 0);
>> +     }
>> +
>> +     if (rtc->features & HAVE_SUBSECOND) {
>> +             /* Disable sub-second interrupt */
>> +             rtc_writel(rtc, LPC24XX_CISS, 0);
>> +     }
>> +
>> +     /* Only 1-second interrupt will generate interrupt */
>> +     rtc_writel(rtc, LPC24XX_CIIR, LPC24XX_IMSEC);
>> +
>> +     /* Enable RTC count */
>> +     rtc_writel(rtc, LPC24XX_CCR, rtc_ccr | LPC24XX_CLKEN);
>> +
>> +     ret = devm_request_irq(&pdev->dev, irq, lpc24xx_rtc_interrupt, 0,
>> +                            pdev->name, rtc);
>> +     if (ret < 0) {
>> +             dev_warn(&pdev->dev, "can't request interrupt\n");
>> +             goto disable_clks;
>> +     }
>> +
>> +     rtc->rtc = devm_rtc_device_register(&pdev->dev, "lpc2k-rtc",
>
> Same comment regarding the lpc2k name, also applies below.

Yeah, I'll change it.

>> +                                         &lpc24xx_rtc_ops, THIS_MODULE);
>> +     if (IS_ERR(rtc->rtc)) {
>> +             dev_err(&pdev->dev, "can't register rtc device\n");
>> +             ret = PTR_ERR(rtc->rtc);
>> +             goto disable_clks;
>> +     }
>> +
>> +     return 0;
>> +
>> +disable_clks:
>> +     clk_disable_unprepare(rtc->clk_reg);
>> +disable_rtc_clk:
>> +     clk_disable_unprepare(rtc->clk_rtc);
>> +     return ret;
>> +}
>> +
>> +static int lpc24xx_rtc_remove(struct platform_device *pdev)
>> +{
>> +     struct lpc24xx_rtc *rtc = platform_get_drvdata(pdev);
>> +
>> +     /*
>> +      * Disable alarm, but leave RTC enabled so it
>> +      * remains valid across reset cycles.
>> +      */
>> +     rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE);
>> +     rtc_writel(rtc, LPC24XX_CCR, 0);
>> +
>> +     clk_disable_unprepare(rtc->clk_rtc);
>> +     clk_disable_unprepare(rtc->clk_reg);
>> +
>> +     return 0;
>> +}
>> +
>> +static struct platform_driver lpc24xx_rtc_driver = {
>> +     .probe  = lpc24xx_rtc_probe,
>> +     .remove = lpc24xx_rtc_remove,
>> +     .driver = {
>> +             .name = "lpc2k-rtc",
>> +             .of_match_table = lpc24xx_rtc_match,
>> +     },
>> +};
>> +module_platform_driver(lpc24xx_rtc_driver);
>> +
>> +MODULE_AUTHOR("Kevin Wells <wellsk40-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org");
>> +MODULE_DESCRIPTION("RTC driver for the LPC24xx SoC");
>> +MODULE_LICENSE("GPL");
>> +MODULE_ALIAS("platform:lpc2k-rtc");

Thanks for looking and commenting.

regards,
Joachim Eastwood
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[PATCH 2/2] doc: dt: add documentation for nxp,lpc1788-rtc

[Joachim Eastwood]

Signed-off-by: Joachim Eastwood <manabian-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 .../devicetree/bindings/rtc/nxp,lpc1788-rtc.txt     | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/rtc/nxp,lpc1788-rtc.txt

diff --git a/Documentation/devicetree/bindings/rtc/nxp,lpc1788-rtc.txt b/Documentation/devicetree/bindings/rtc/nxp,lpc1788-rtc.txt
new file mode 100644
index 000000000000..ad41a040432c
--- /dev/null
+++ b/Documentation/devicetree/bindings/rtc/nxp,lpc1788-rtc.txt
@@ -0,0 +1,21 @@
+NXP LPC1788 real-time clock
+
+The LPC1788 RTC provides calendar and clock functionality
+together with periodic tick and alarm interrupt support.
+
+Required properties:
+- compatible	: must contain "nxp,lpc1788-rtc"
+- reg		: Specifies base physical address and size of the registers.
+- interrupts	: A single interrupt specifier.
+- clocks	: Must contain entries for rtc and register clock
+- clock-names	: Must contain "rtc" and "reg"
+  See ../clocks/clock-bindings.txt for details.
+
+Example:
+rtc: rtc@40046000 {
+	compatible = "nxp,lpc1788-rtc";
+	reg = <0x40046000 0x1000>;
+	interrupts = <47>;
+	clocks = <&creg_clk 0>, <&ccu1 CLK_CPU_BUS>;
+	clock-names = "rtc", "reg";
+};
-- 
1.8.0

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