[PATCH v3 0/6] RZN1 RTC support

[PATCH v3 0/6] RZN1 RTC support

[Miquel Raynal]

Hello,

This small series adds support for the RZN1 RTC.

Despite its limitations, I found useful to at least have alarm and
offset support.

The RTC hclk fix has been merged in the renesas-clk-for-v5.19 branch so
I dropped it from the series.

Cheers,
Miquèl

Changes in v3:
* Collected tags.
* s/soc:/clk:/ in the clock commit title.
* Dropped the RTC hclk fix which has already been applied.
* Added the power-domain properties both in the bindings and in the DT.
* Used runtime PM to enable the clock instead of using the clk API
  directly. 

Changes in v2:
* Fixed the error path in the clk driver, where I missed to release a
  spin_lock.
* Collected tags.
* Moved the rtc subnode in the dt to keep the nodes ordered by unit
  address.
* Dropped the useless "oneOf" statement in the bindings (compatible
  property).
* Dropped the start-year property in the bindings (already defined).
* Avoided rollover calculations that could be more easily handled (and
  reviewed) with a time64_t conversion.
* Returned ERANGE instead of EOPNOTSUPP when the alarm date is not
  valid.
* Cleared RTC_FEATURE_UPDATE_INTERRUPT to avoid warning from the tools.
* Dropped the sysctl patch adding the reset helper, instead fulfilled
  the description of the RTC clock so that when requesting this clock to
  be enabled, the idle bit is released.
* Avoided rollover calculations that could be more easily handled
  (and reviewed) with a time64_t conversion.
* Fixed the max_range value, after a rtc-range test and looking at other
  implementations.

Michel Pollet (1):
  rtc: rzn1: Add new RTC driver

Miquel Raynal (5):
  dt-bindings: rtc: rzn1: Describe the RZN1 RTC
  rtc: rzn1: Add alarm support
  rtc: rzn1: Add oscillator offset support
  MAINTAINERS: Add myself as maintainer of the RZN1 RTC driver
  ARM: dts: r9a06g032: Describe the RTC

 .../bindings/rtc/renesas,rzn1-rtc.yaml        |  70 +++
 MAINTAINERS                                   |   8 +
 arch/arm/boot/dts/r9a06g032.dtsi              |  13 +
 drivers/rtc/Kconfig                           |   7 +
 drivers/rtc/Makefile                          |   1 +
 drivers/rtc/rtc-rzn1.c                        | 423 ++++++++++++++++++
 6 files changed, 522 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
 create mode 100644 drivers/rtc/rtc-rzn1.c

-- 
2.27.0

[PATCH v3 1/6] dt-bindings: rtc: rzn1: Describe the RZN1 RTC

[Miquel Raynal]

Add new binding file for this RTC.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
 .../bindings/rtc/renesas,rzn1-rtc.yaml        | 70 +++++++++++++++++++
 1 file changed, 70 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml

diff --git a/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml b/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
new file mode 100644
index 000000000000..2d4741f51663
--- /dev/null
+++ b/Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
@@ -0,0 +1,70 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/rtc/renesas,rzn1-rtc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Renesas RZ/N1 SoCs Real-Time Clock DT bindings
+
+maintainers:
+  - Miquel Raynal <miquel.raynal@bootlin.com>
+
+allOf:
+  - $ref: rtc.yaml#
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - renesas,r9a06g032-rtc
+      - const: renesas,rzn1-rtc
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    minItems: 3
+    maxItems: 3
+
+  interrupt-names:
+    items:
+      - const: alarm
+      - const: timer
+      - const: pps
+
+  clocks:
+    maxItems: 1
+
+  clock-names:
+    const: hclk
+
+  power-domains:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - interrupt-names
+  - clocks
+  - clock-names
+  - power-domains
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/clock/r9a06g032-sysctrl.h>
+    rtc@40006000 {
+       compatible = "renesas,r9a06g032-rtc", "renesas,rzn1-rtc";
+       reg = <0x40006000 0x1000>;
+       interrupts = <GIC_SPI 66 IRQ_TYPE_EDGE_RISING>,
+                    <GIC_SPI 67 IRQ_TYPE_EDGE_RISING>,
+                    <GIC_SPI 68 IRQ_TYPE_EDGE_RISING>;
+       interrupt-names = "alarm", "timer", "pps";
+       clocks = <&sysctrl R9A06G032_HCLK_RTC>;
+       clock-names = "hclk";
+       power-domains = <&sysctrl>;
+       start-year = <2000>;
+     };
-- 
2.27.0

[PATCH v3 2/6] rtc: rzn1: Add new RTC driver

[Miquel Raynal]

From: Michel Pollet <michel.pollet@bp.renesas.com>

Add a basic RTC driver for the RZ/N1.

Signed-off-by: Michel Pollet <michel.pollet@bp.renesas.com>
Co-developed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
 drivers/rtc/Kconfig    |   7 ++
 drivers/rtc/Makefile   |   1 +
 drivers/rtc/rtc-rzn1.c | 246 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 254 insertions(+)
 create mode 100644 drivers/rtc/rtc-rzn1.c

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 41c65b4d2baf..a00f901b5c1d 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -1548,6 +1548,13 @@ config RTC_DRV_RS5C313
 	help
 	  If you say yes here you get support for the Ricoh RS5C313 RTC chips.
 
+config RTC_DRV_RZN1
+	tristate "Renesas RZ/N1 RTC"
+	depends on ARCH_RZN1 || COMPILE_TEST
+	depends on OF && HAS_IOMEM
+	help
+	  If you say yes here you get support for the Renesas RZ/N1 RTC.
+
 config RTC_DRV_GENERIC
 	tristate "Generic RTC support"
 	# Please consider writing a new RTC driver instead of using the generic
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 2d827d8261d5..fb04467b652d 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -151,6 +151,7 @@ obj-$(CONFIG_RTC_DRV_RX6110)	+= rtc-rx6110.o
 obj-$(CONFIG_RTC_DRV_RX8010)	+= rtc-rx8010.o
 obj-$(CONFIG_RTC_DRV_RX8025)	+= rtc-rx8025.o
 obj-$(CONFIG_RTC_DRV_RX8581)	+= rtc-rx8581.o
+obj-$(CONFIG_RTC_DRV_RZN1)	+= rtc-rzn1.o
 obj-$(CONFIG_RTC_DRV_S35390A)	+= rtc-s35390a.o
 obj-$(CONFIG_RTC_DRV_S3C)	+= rtc-s3c.o
 obj-$(CONFIG_RTC_DRV_S5M)	+= rtc-s5m.o
diff --git a/drivers/rtc/rtc-rzn1.c b/drivers/rtc/rtc-rzn1.c
new file mode 100644
index 000000000000..19f323f62f20
--- /dev/null
+++ b/drivers/rtc/rtc-rzn1.c
@@ -0,0 +1,246 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Renesas RZN1 Real Time Clock interface for Linux
+ *
+ * Copyright:
+ * - 2014 Renesas Electronics Europe Limited
+ * - 2022 Schneider Electric
+ *
+ * Authors:
+ * - Michel Pollet <michel.pollet@bp.renesas.com>, <buserror@gmail.com>
+ * - Miquel Raynal <miquel.raynal@bootlin.com>
+ */
+
+#include <linux/bcd.h>
+#include <linux/clk.h>
+#include <linux/init.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/rtc.h>
+#include <linux/soc/renesas/r9a06g032-sysctrl.h>
+
+#define RZN1_RTC_CTL0 0x00
+#define   RZN1_RTC_CTL0_SLSB_SUBU 0
+#define   RZN1_RTC_CTL0_SLSB_SCMP BIT(4)
+#define   RZN1_RTC_CTL0_AMPM BIT(5)
+#define   RZN1_RTC_CTL0_CE BIT(7)
+
+#define RZN1_RTC_CTL1 0x04
+#define   RZN1_RTC_CTL1_ALME BIT(4)
+
+#define RZN1_RTC_CTL2 0x08
+#define   RZN1_RTC_CTL2_WAIT BIT(0)
+#define   RZN1_RTC_CTL2_WST BIT(1)
+#define   RZN1_RTC_CTL2_WUST BIT(5)
+#define   RZN1_RTC_CTL2_STOPPED (RZN1_RTC_CTL2_WAIT | RZN1_RTC_CTL2_WST)
+
+#define RZN1_RTC_SEC 0x14
+#define RZN1_RTC_MIN 0x18
+#define RZN1_RTC_HOUR 0x1c
+#define RZN1_RTC_WEEK 0x20
+#define RZN1_RTC_DAY 0x24
+#define RZN1_RTC_MONTH 0x28
+#define RZN1_RTC_YEAR 0x2c
+
+#define RZN1_RTC_SUBU 0x38
+#define   RZN1_RTC_SUBU_DEV BIT(7)
+#define   RZN1_RTC_SUBU_DECR BIT(6)
+
+#define RZN1_RTC_ALM 0x40
+#define RZN1_RTC_ALH 0x44
+#define RZN1_RTC_ALW 0x48
+
+#define RZN1_RTC_SECC 0x4c
+#define RZN1_RTC_MINC 0x50
+#define RZN1_RTC_HOURC 0x54
+#define RZN1_RTC_WEEKC 0x58
+#define RZN1_RTC_DAYC 0x5c
+#define RZN1_RTC_MONTHC 0x60
+#define RZN1_RTC_YEARC 0x64
+
+struct rzn1_rtc {
+	struct rtc_device *rtcdev;
+	void __iomem *base;
+	struct clk *clk;
+};
+
+static void rzn1_rtc_get_time_snapshot(struct rzn1_rtc *rtc, struct rtc_time *tm)
+{
+	tm->tm_sec = readl(rtc->base + RZN1_RTC_SECC);
+	tm->tm_min = readl(rtc->base + RZN1_RTC_MINC);
+	tm->tm_hour = readl(rtc->base + RZN1_RTC_HOURC);
+	tm->tm_wday = readl(rtc->base + RZN1_RTC_WEEKC);
+	tm->tm_mday = readl(rtc->base + RZN1_RTC_DAYC);
+	tm->tm_mon = readl(rtc->base + RZN1_RTC_MONTHC);
+	tm->tm_year = readl(rtc->base + RZN1_RTC_YEARC);
+}
+
+static unsigned int rzn1_rtc_tm_to_wday(struct rtc_time *tm)
+{
+	time64_t time;
+	unsigned int days;
+	u32 secs;
+
+	time = rtc_tm_to_time64(tm);
+	days = div_s64_rem(time, 86400, &secs);
+
+	/* day of the week, 1970-01-01 was a Thursday */
+	return (days + 4) % 7;
+}
+
+static int rzn1_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	struct rzn1_rtc *rtc = dev_get_drvdata(dev);
+	u32 val, secs;
+
+	/*
+	 * The RTC was not started or is stopped and thus does not carry the
+	 * proper time/date.
+	 */
+	val = readl(rtc->base + RZN1_RTC_CTL2);
+	if (val & RZN1_RTC_CTL2_STOPPED)
+		return -EINVAL;
+
+	rzn1_rtc_get_time_snapshot(rtc, tm);
+	secs = readl(rtc->base + RZN1_RTC_SECC);
+	if (tm->tm_sec != secs)
+		rzn1_rtc_get_time_snapshot(rtc, tm);
+
+	tm->tm_sec = bcd2bin(tm->tm_sec);
+	tm->tm_min = bcd2bin(tm->tm_min);
+	tm->tm_hour = bcd2bin(tm->tm_hour);
+	tm->tm_wday = bcd2bin(tm->tm_wday);
+	tm->tm_mday = bcd2bin(tm->tm_mday);
+	tm->tm_mon = bcd2bin(tm->tm_mon);
+	tm->tm_year = bcd2bin(tm->tm_year);
+
+	return 0;
+}
+
+static int rzn1_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct rzn1_rtc *rtc = dev_get_drvdata(dev);
+	u32 val;
+	int ret;
+
+	tm->tm_sec = bin2bcd(tm->tm_sec);
+	tm->tm_min = bin2bcd(tm->tm_min);
+	tm->tm_hour = bin2bcd(tm->tm_hour);
+	tm->tm_wday = bin2bcd(rzn1_rtc_tm_to_wday(tm));
+	tm->tm_mday = bin2bcd(tm->tm_mday);
+	tm->tm_mon = bin2bcd(tm->tm_mon);
+	tm->tm_year = bin2bcd(tm->tm_year);
+
+	val = readl(rtc->base + RZN1_RTC_CTL2);
+	if (!(val & RZN1_RTC_CTL2_STOPPED)) {
+		/* Hold the counter if it was counting up */
+		writel(RZN1_RTC_CTL2_WAIT, rtc->base + RZN1_RTC_CTL2);
+
+		/* Wait for the counter to stop: two 32k clock cycles */
+		usleep_range(61, 100);
+		ret = readl_poll_timeout(rtc->base + RZN1_RTC_CTL2, val,
+					 val & RZN1_RTC_CTL2_WST, 0, 100);
+		if (ret)
+			return ret;
+	}
+
+	writel(tm->tm_sec, rtc->base + RZN1_RTC_SEC);
+	writel(tm->tm_min, rtc->base + RZN1_RTC_MIN);
+	writel(tm->tm_hour, rtc->base + RZN1_RTC_HOUR);
+	writel(tm->tm_wday, rtc->base + RZN1_RTC_WEEK);
+	writel(tm->tm_mday, rtc->base + RZN1_RTC_DAY);
+	writel(tm->tm_mon, rtc->base + RZN1_RTC_MONTH);
+	writel(tm->tm_year, rtc->base + RZN1_RTC_YEAR);
+	writel(0, rtc->base + RZN1_RTC_CTL2);
+
+	return 0;
+}
+
+static const struct rtc_class_ops rzn1_rtc_ops = {
+	.read_time = rzn1_rtc_read_time,
+	.set_time = rzn1_rtc_set_time,
+};
+
+static int rzn1_rtc_probe(struct platform_device *pdev)
+{
+	struct rzn1_rtc *rtc;
+	int ret;
+
+	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
+	if (!rtc)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, rtc);
+
+	rtc->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(rtc->base))
+		return dev_err_probe(&pdev->dev, PTR_ERR(rtc->base), "Missing reg\n");
+
+	rtc->rtcdev = devm_rtc_allocate_device(&pdev->dev);
+	if (IS_ERR(rtc->rtcdev))
+		return PTR_ERR(rtc);
+
+	rtc->rtcdev->range_min = RTC_TIMESTAMP_BEGIN_2000;
+	rtc->rtcdev->range_max = RTC_TIMESTAMP_END_2099;
+	rtc->rtcdev->ops = &rzn1_rtc_ops;
+	clear_bit(RTC_FEATURE_ALARM, rtc->rtcdev->features);
+	clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->rtcdev->features);
+
+	pm_runtime_enable(&pdev->dev);
+	pm_runtime_get_sync(&pdev->dev);
+
+	/*
+	 * Ensure the clock counter is enabled.
+	 * Set 24-hour mode and possible oscillator offset compensation in SUBU mode.
+	 */
+	writel(RZN1_RTC_CTL0_CE | RZN1_RTC_CTL0_AMPM | RZN1_RTC_CTL0_SLSB_SUBU,
+	       rtc->base + RZN1_RTC_CTL0);
+
+	/* Disable all interrupts */
+	writel(0, rtc->base + RZN1_RTC_CTL1);
+
+	ret = devm_rtc_register_device(rtc->rtcdev);
+	if (ret)
+		goto dis_runtime_pm;
+
+	return 0;
+
+dis_runtime_pm:
+	pm_runtime_put_sync(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
+
+	return ret;
+}
+
+static int rzn1_rtc_remove(struct platform_device *pdev)
+{
+	pm_runtime_put_sync(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
+
+	return 0;
+}
+
+static const struct of_device_id rzn1_rtc_of_match[] = {
+	{ .compatible	= "renesas,rzn1-rtc" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, rzn1_rtc_of_match);
+
+static struct platform_driver rzn1_rtc_driver = {
+	.probe = rzn1_rtc_probe,
+	.remove = rzn1_rtc_remove,
+	.driver = {
+		.name	= "rzn1-rtc",
+		.owner	= THIS_MODULE,
+		.of_match_table = rzn1_rtc_of_match,
+	},
+};
+module_platform_driver(rzn1_rtc_driver);
+
+MODULE_AUTHOR("Michel Pollet <Michel.Pollet@bp.renesas.com");
+MODULE_AUTHOR("Miquel Raynal <miquel.raynal@bootlin.com");
+MODULE_DESCRIPTION("RZ/N1 RTC driver");
+MODULE_LICENSE("GPL");
-- 
2.27.0

[PATCH v3 3/6] rtc: rzn1: Add alarm support

[Miquel Raynal]

The RZN1 RTC can trigger an interrupt when reaching a particular date up
to 7 days ahead. Bring support for this alarm.

One drawback though, the granularity is about a minute.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
 drivers/rtc/rtc-rzn1.c | 106 ++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 105 insertions(+), 1 deletion(-)

diff --git a/drivers/rtc/rtc-rzn1.c b/drivers/rtc/rtc-rzn1.c
index 19f323f62f20..5efbc1aa9040 100644
--- a/drivers/rtc/rtc-rzn1.c
+++ b/drivers/rtc/rtc-rzn1.c
@@ -159,14 +159,107 @@ static int rzn1_rtc_set_time(struct device *dev, struct rtc_time *tm)
 	return 0;
 }
 
+static irqreturn_t rzn1_rtc_alarm_irq(int irq, void *dev_id)
+{
+	struct rzn1_rtc *rtc = dev_id;
+
+	rtc_update_irq(rtc->rtcdev, 1, RTC_AF | RTC_IRQF);
+
+	return IRQ_HANDLED;
+}
+
+static int rzn1_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
+{
+	struct rzn1_rtc *rtc = dev_get_drvdata(dev);
+	u32 ctl1 = readl(rtc->base + RZN1_RTC_CTL1);
+
+	if (enable)
+		ctl1 |= RZN1_RTC_CTL1_ALME;
+	else
+		ctl1 &= ~RZN1_RTC_CTL1_ALME;
+
+	writel(ctl1, rtc->base + RZN1_RTC_CTL1);
+
+	return 0;
+}
+
+static int rzn1_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct rzn1_rtc *rtc = dev_get_drvdata(dev);
+	struct rtc_time *tm = &alrm->time;
+	unsigned int min, hour, wday, delta_days;
+	time64_t alarm;
+	u32 ctl1;
+	int ret;
+
+	ret = rzn1_rtc_read_time(dev, tm);
+	if (ret)
+		return ret;
+
+	min = readl(rtc->base + RZN1_RTC_ALM);
+	hour = readl(rtc->base + RZN1_RTC_ALH);
+	wday = readl(rtc->base + RZN1_RTC_ALW);
+
+	tm->tm_sec = 0;
+	tm->tm_min = bcd2bin(min);
+	tm->tm_hour = bcd2bin(hour);
+	delta_days = ((fls(wday) - 1) - tm->tm_wday + 7) % 7;
+	tm->tm_wday = fls(wday) - 1;
+
+	if (delta_days) {
+		alarm = rtc_tm_to_time64(tm) + (delta_days * 86400);
+		rtc_time64_to_tm(alarm, tm);
+	}
+
+	ctl1 = readl(rtc->base + RZN1_RTC_CTL1);
+	alrm->enabled = !!(ctl1 & RZN1_RTC_CTL1_ALME);
+
+	return 0;
+}
+
+static int rzn1_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct rzn1_rtc *rtc = dev_get_drvdata(dev);
+	struct rtc_time *tm = &alrm->time, tm_now;
+	unsigned long alarm, farest;
+	unsigned int days_ahead, wday;
+	int ret;
+
+	ret = rzn1_rtc_read_time(dev, &tm_now);
+	if (ret)
+		return ret;
+
+	/* We cannot set alarms more than one week ahead */
+	farest = rtc_tm_to_time64(&tm_now) + (7 * 86400);
+	alarm = rtc_tm_to_time64(tm);
+	if (time_after(alarm, farest))
+		return -ERANGE;
+
+	/* Convert alarm day into week day */
+	days_ahead = tm->tm_mday - tm_now.tm_mday;
+	wday = (tm_now.tm_wday + days_ahead) % 7;
+
+	writel(bin2bcd(tm->tm_min), rtc->base + RZN1_RTC_ALM);
+	writel(bin2bcd(tm->tm_hour), rtc->base + RZN1_RTC_ALH);
+	writel(BIT(wday), rtc->base + RZN1_RTC_ALW);
+
+	rzn1_rtc_alarm_irq_enable(dev, alrm->enabled);
+
+	return 0;
+}
+
 static const struct rtc_class_ops rzn1_rtc_ops = {
 	.read_time = rzn1_rtc_read_time,
 	.set_time = rzn1_rtc_set_time,
+	.read_alarm = rzn1_rtc_read_alarm,
+	.set_alarm = rzn1_rtc_set_alarm,
+	.alarm_irq_enable = rzn1_rtc_alarm_irq_enable,
 };
 
 static int rzn1_rtc_probe(struct platform_device *pdev)
 {
 	struct rzn1_rtc *rtc;
+	int alarm_irq;
 	int ret;
 
 	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
@@ -179,6 +272,10 @@ static int rzn1_rtc_probe(struct platform_device *pdev)
 	if (IS_ERR(rtc->base))
 		return dev_err_probe(&pdev->dev, PTR_ERR(rtc->base), "Missing reg\n");
 
+	alarm_irq = platform_get_irq(pdev, 0);
+	if (alarm_irq < 0)
+		return dev_err_probe(&pdev->dev, alarm_irq, "Missing timer IRQ\n");
+
 	rtc->rtcdev = devm_rtc_allocate_device(&pdev->dev);
 	if (IS_ERR(rtc->rtcdev))
 		return PTR_ERR(rtc);
@@ -186,7 +283,7 @@ static int rzn1_rtc_probe(struct platform_device *pdev)
 	rtc->rtcdev->range_min = RTC_TIMESTAMP_BEGIN_2000;
 	rtc->rtcdev->range_max = RTC_TIMESTAMP_END_2099;
 	rtc->rtcdev->ops = &rzn1_rtc_ops;
-	clear_bit(RTC_FEATURE_ALARM, rtc->rtcdev->features);
+	set_bit(RTC_FEATURE_ALARM_RES_MINUTE, rtc->rtcdev->features);
 	clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->rtcdev->features);
 
 	pm_runtime_enable(&pdev->dev);
@@ -202,6 +299,13 @@ static int rzn1_rtc_probe(struct platform_device *pdev)
 	/* Disable all interrupts */
 	writel(0, rtc->base + RZN1_RTC_CTL1);
 
+	ret = devm_request_irq(&pdev->dev, alarm_irq, rzn1_rtc_alarm_irq, 0,
+			       dev_name(&pdev->dev), rtc);
+	if (ret) {
+		dev_err(&pdev->dev, "RTC timer interrupt not available\n");
+		goto dis_runtime_pm;
+	}
+
 	ret = devm_rtc_register_device(rtc->rtcdev);
 	if (ret)
 		goto dis_runtime_pm;
-- 
2.27.0

[PATCH v3 4/6] rtc: rzn1: Add oscillator offset support

[Miquel Raynal]

The RZN1 RTC can compensate the imprecision of the oscillator up to
approximately 190ppm.

Seconds can last slightly shorter or longer depending on the
configuration.

Below ~65ppm of correction, we can change the time spent in a second
every minute, which is the most accurate compensation that the RTC can
offer. Above, the compensation will be active every 20s.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
 drivers/rtc/rtc-rzn1.c | 73 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 73 insertions(+)

diff --git a/drivers/rtc/rtc-rzn1.c b/drivers/rtc/rtc-rzn1.c
index 5efbc1aa9040..6d05d0454a98 100644
--- a/drivers/rtc/rtc-rzn1.c
+++ b/drivers/rtc/rtc-rzn1.c
@@ -248,12 +248,85 @@ static int rzn1_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 	return 0;
 }
 
+static int rzn1_rtc_read_offset(struct device *dev, long *offset)
+{
+	struct rzn1_rtc *rtc = dev_get_drvdata(dev);
+	unsigned int ppb_per_step;
+	bool subtract;
+	u32 val;
+
+	val = readl(rtc->base + RZN1_RTC_SUBU);
+	ppb_per_step = val & RZN1_RTC_SUBU_DEV ? 1017 : 3051;
+	subtract = val & RZN1_RTC_SUBU_DECR;
+	val &= 0x3F;
+
+	if (!val)
+		*offset = 0;
+	else if (subtract)
+		*offset = -(((~val) & 0x3F) + 1) * ppb_per_step;
+	else
+		*offset = (val - 1) * ppb_per_step;
+
+	return 0;
+}
+
+static int rzn1_rtc_set_offset(struct device *dev, long offset)
+{
+	struct rzn1_rtc *rtc = dev_get_drvdata(dev);
+	unsigned int steps, ppb_per_step;
+	int stepsh, stepsl;
+	u32 val;
+	int ret;
+
+	/*
+	 * Check which resolution mode (every 20 or 60s) can be used.
+	 * Between 2 and 124 clock pulses can be added or substracted.
+	 *
+	 * In 20s mode, the minimum resolution is 2 / (32768 * 20) which is
+	 * close to 3051 ppb. In 60s mode, the resolution is closer to 1017.
+	 */
+	stepsh = DIV_ROUND_CLOSEST(offset, 1017);
+	stepsl = DIV_ROUND_CLOSEST(offset, 3051);
+
+	if (stepsh >= -0x3E && stepsh <= 0x3E) {
+		ppb_per_step = 1017;
+		steps = stepsh;
+		val |= RZN1_RTC_SUBU_DEV;
+	} else if (stepsl >= -0x3E && stepsl <= 0x3E) {
+		ppb_per_step = 3051;
+		steps = stepsl;
+	} else {
+		return -ERANGE;
+	}
+
+	if (!steps)
+		return 0;
+
+	if (steps > 0) {
+		val |= steps + 1;
+	} else {
+		val |= RZN1_RTC_SUBU_DECR;
+		val |= (~(-steps - 1)) & 0x3F;
+	}
+
+	ret = readl_poll_timeout(rtc->base + RZN1_RTC_CTL2, val,
+				 !(val & RZN1_RTC_CTL2_WUST), 100, 2000000);
+	if (ret)
+		return ret;
+
+	writel(val, rtc->base + RZN1_RTC_SUBU);
+
+	return 0;
+}
+
 static const struct rtc_class_ops rzn1_rtc_ops = {
 	.read_time = rzn1_rtc_read_time,
 	.set_time = rzn1_rtc_set_time,
 	.read_alarm = rzn1_rtc_read_alarm,
 	.set_alarm = rzn1_rtc_set_alarm,
 	.alarm_irq_enable = rzn1_rtc_alarm_irq_enable,
+	.read_offset = rzn1_rtc_read_offset,
+	.set_offset = rzn1_rtc_set_offset,
 };
 
 static int rzn1_rtc_probe(struct platform_device *pdev)
-- 
2.27.0

[PATCH v3 5/6] MAINTAINERS: Add myself as maintainer of the RZN1 RTC driver

[Miquel Raynal]

After contributing it, I'll volunteer to maintain it.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
 MAINTAINERS | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 9cf74e4eacce..cc4a3cca022e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16847,6 +16847,14 @@ S:	Supported
 F:	Documentation/devicetree/bindings/iio/adc/renesas,rzg2l-adc.yaml
 F:	drivers/iio/adc/rzg2l_adc.c
 
+RENESAS RZ/N1 RTC CONTROLLER DRIVER
+M:	Miquel Raynal <miquel.raynal@bootlin.com>
+L:	linux-rtc@vger.kernel.org
+L:	linux-renesas-soc@vger.kernel.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/rtc/renesas,rzn1-rtc.yaml
+F:	drivers/rtc/rtc-rzn1.c
+
 RENESAS R-CAR GEN3 & RZ/N1 NAND CONTROLLER DRIVER
 M:	Miquel Raynal <miquel.raynal@bootlin.com>
 L:	linux-mtd@lists.infradead.org
-- 
2.27.0

[PATCH v3 6/6] ARM: dts: r9a06g032: Describe the RTC

[Miquel Raynal]

Describe the SoC RTC which counts time and provides alarm support.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
 arch/arm/boot/dts/r9a06g032.dtsi | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/arch/arm/boot/dts/r9a06g032.dtsi b/arch/arm/boot/dts/r9a06g032.dtsi
index eaf305d938cc..a35bd19c616a 100644
--- a/arch/arm/boot/dts/r9a06g032.dtsi
+++ b/arch/arm/boot/dts/r9a06g032.dtsi
@@ -66,6 +66,19 @@ soc {
 		interrupt-parent = <&gic>;
 		ranges;
 
+		rtc0: rtc@40006000 {
+			compatible = "renesas,r9a06g032-rtc", "renesas,rzn1-rtc";
+			reg = <0x40006000 0x1000>;
+			interrupts = <GIC_SPI 66 IRQ_TYPE_EDGE_RISING>,
+				     <GIC_SPI 67 IRQ_TYPE_EDGE_RISING>,
+				     <GIC_SPI 68 IRQ_TYPE_EDGE_RISING>;
+			interrupt-names = "alarm", "timer", "pps";
+			clocks = <&sysctrl R9A06G032_HCLK_RTC>;
+			clock-names = "hclk";
+			power-domains = <&sysctrl>;
+			status = "disabled";
+		};
+
 		wdt0: watchdog@40008000 {
 			compatible = "renesas,r9a06g032-wdt", "renesas,rzn1-wdt";
 			reg = <0x40008000 0x1000>;
-- 
2.27.0

Re: [PATCH v3 2/6] rtc: rzn1: Add new RTC driver

[Geert Uytterhoeven]

Hi Miquel,

On Fri, Apr 29, 2022 at 12:46 PM Miquel Raynal
<miquel.raynal@bootlin.com> wrote:
> From: Michel Pollet <michel.pollet@bp.renesas.com>
>
> Add a basic RTC driver for the RZ/N1.
>
> Signed-off-by: Michel Pollet <michel.pollet@bp.renesas.com>
> Co-developed-by: Miquel Raynal <miquel.raynal@bootlin.com>
> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

Thanks for your patch!

> --- /dev/null
> +++ b/drivers/rtc/rtc-rzn1.c
> @@ -0,0 +1,246 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Renesas RZN1 Real Time Clock interface for Linux

RZ/N1

> +static int rzn1_rtc_probe(struct platform_device *pdev)
> +{
> +       struct rzn1_rtc *rtc;
> +       int ret;
> +
> +       rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
> +       if (!rtc)
> +               return -ENOMEM;
> +
> +       platform_set_drvdata(pdev, rtc);
> +
> +       rtc->base = devm_platform_ioremap_resource(pdev, 0);
> +       if (IS_ERR(rtc->base))
> +               return dev_err_probe(&pdev->dev, PTR_ERR(rtc->base), "Missing reg\n");
> +
> +       rtc->rtcdev = devm_rtc_allocate_device(&pdev->dev);
> +       if (IS_ERR(rtc->rtcdev))
> +               return PTR_ERR(rtc);
> +
> +       rtc->rtcdev->range_min = RTC_TIMESTAMP_BEGIN_2000;
> +       rtc->rtcdev->range_max = RTC_TIMESTAMP_END_2099;
> +       rtc->rtcdev->ops = &rzn1_rtc_ops;
> +       clear_bit(RTC_FEATURE_ALARM, rtc->rtcdev->features);
> +       clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->rtcdev->features);
> +
> +       pm_runtime_enable(&pdev->dev);
> +       pm_runtime_get_sync(&pdev->dev);

While this call cannot really fail on this platform, you may want to
call pm_runtime_resume_and_get() instead, and check its return
value (else the janitors will make that change later ;-)

> +
> +       /*
> +        * Ensure the clock counter is enabled.
> +        * Set 24-hour mode and possible oscillator offset compensation in SUBU mode.
> +        */
> +       writel(RZN1_RTC_CTL0_CE | RZN1_RTC_CTL0_AMPM | RZN1_RTC_CTL0_SLSB_SUBU,
> +              rtc->base + RZN1_RTC_CTL0);
> +
> +       /* Disable all interrupts */
> +       writel(0, rtc->base + RZN1_RTC_CTL1);
> +
> +       ret = devm_rtc_register_device(rtc->rtcdev);
> +       if (ret)
> +               goto dis_runtime_pm;
> +
> +       return 0;
> +
> +dis_runtime_pm:
> +       pm_runtime_put_sync(&pdev->dev);

pm_runtime_put() should be fine, no need for the synchronous version.

> +       pm_runtime_disable(&pdev->dev);
> +
> +       return ret;
> +}
> +
> +static int rzn1_rtc_remove(struct platform_device *pdev)
> +{
> +       pm_runtime_put_sync(&pdev->dev);

pm_runtime_put().

> +       pm_runtime_disable(&pdev->dev);
> +
> +       return 0;
> +}

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH v3 3/6] rtc: rzn1: Add alarm support

[Geert Uytterhoeven]

Hi Miquel,

On Fri, Apr 29, 2022 at 12:46 PM Miquel Raynal
<miquel.raynal@bootlin.com> wrote:
> The RZN1 RTC can trigger an interrupt when reaching a particular date up
> to 7 days ahead. Bring support for this alarm.
>
> One drawback though, the granularity is about a minute.
>
> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

Thanks for your patch!

> --- a/drivers/rtc/rtc-rzn1.c
> +++ b/drivers/rtc/rtc-rzn1.c
> @@ -179,6 +272,10 @@ static int rzn1_rtc_probe(struct platform_device *pdev)
>         if (IS_ERR(rtc->base))
>                 return dev_err_probe(&pdev->dev, PTR_ERR(rtc->base), "Missing reg\n");
>
> +       alarm_irq = platform_get_irq(pdev, 0);
> +       if (alarm_irq < 0)
> +               return dev_err_probe(&pdev->dev, alarm_irq, "Missing timer IRQ\n");

No need to print a message, platform_get_irq() already does that.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH v3 2/6] rtc: rzn1: Add new RTC driver

[Miquel Raynal]

Hi Geert,

geert@linux-m68k.org wrote on Mon, 2 May 2022 16:41:20 +0200:

> Hi Miquel,
> 
> On Fri, Apr 29, 2022 at 12:46 PM Miquel Raynal
> <miquel.raynal@bootlin.com> wrote:
> > From: Michel Pollet <michel.pollet@bp.renesas.com>
> >
> > Add a basic RTC driver for the RZ/N1.
> >
> > Signed-off-by: Michel Pollet <michel.pollet@bp.renesas.com>
> > Co-developed-by: Miquel Raynal <miquel.raynal@bootlin.com>
> > Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>  
> 
> Thanks for your patch!
> 
> > --- /dev/null
> > +++ b/drivers/rtc/rtc-rzn1.c
> > @@ -0,0 +1,246 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * Renesas RZN1 Real Time Clock interface for Linux  
> 
> RZ/N1

Done.

> 
> > +static int rzn1_rtc_probe(struct platform_device *pdev)
> > +{
> > +       struct rzn1_rtc *rtc;
> > +       int ret;
> > +
> > +       rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
> > +       if (!rtc)
> > +               return -ENOMEM;
> > +
> > +       platform_set_drvdata(pdev, rtc);
> > +
> > +       rtc->base = devm_platform_ioremap_resource(pdev, 0);
> > +       if (IS_ERR(rtc->base))
> > +               return dev_err_probe(&pdev->dev, PTR_ERR(rtc->base), "Missing reg\n");
> > +
> > +       rtc->rtcdev = devm_rtc_allocate_device(&pdev->dev);
> > +       if (IS_ERR(rtc->rtcdev))
> > +               return PTR_ERR(rtc);
> > +
> > +       rtc->rtcdev->range_min = RTC_TIMESTAMP_BEGIN_2000;
> > +       rtc->rtcdev->range_max = RTC_TIMESTAMP_END_2099;
> > +       rtc->rtcdev->ops = &rzn1_rtc_ops;
> > +       clear_bit(RTC_FEATURE_ALARM, rtc->rtcdev->features);
> > +       clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->rtcdev->features);
> > +
> > +       pm_runtime_enable(&pdev->dev);
> > +       pm_runtime_get_sync(&pdev->dev);  
> 
> While this call cannot really fail on this platform, you may want to
> call pm_runtime_resume_and_get() instead, and check its return
> value (else the janitors will make that change later ;-)

Right, I misunderstood the doc, I'll change it.

> 
> > +
> > +       /*
> > +        * Ensure the clock counter is enabled.
> > +        * Set 24-hour mode and possible oscillator offset compensation in SUBU mode.
> > +        */
> > +       writel(RZN1_RTC_CTL0_CE | RZN1_RTC_CTL0_AMPM | RZN1_RTC_CTL0_SLSB_SUBU,
> > +              rtc->base + RZN1_RTC_CTL0);
> > +
> > +       /* Disable all interrupts */
> > +       writel(0, rtc->base + RZN1_RTC_CTL1);
> > +
> > +       ret = devm_rtc_register_device(rtc->rtcdev);
> > +       if (ret)
> > +               goto dis_runtime_pm;
> > +
> > +       return 0;
> > +
> > +dis_runtime_pm:
> > +       pm_runtime_put_sync(&pdev->dev);  
> 
> pm_runtime_put() should be fine, no need for the synchronous version.

Right, there is no need for the _sync() version here and below I
believe.

> 
> > +       pm_runtime_disable(&pdev->dev);
> > +
> > +       return ret;
> > +}
> > +
> > +static int rzn1_rtc_remove(struct platform_device *pdev)
> > +{
> > +       pm_runtime_put_sync(&pdev->dev);  
> 
> pm_runtime_put().
> 
> > +       pm_runtime_disable(&pdev->dev);
> > +
> > +       return 0;
> > +}  
> 
> Gr{oetje,eeting}s,
> 
>                         Geert
> 
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
> 
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                 -- Linus Torvalds


Thanks,
Miquèl