diff mbox series

[06/12] rtc: renesas-rtca3: Add driver for RTCA-3 available on Renesas RZ/G3S SoC

Message ID 20240614071932.1014067-7-claudiu.beznea.uj@bp.renesas.com (mailing list archive)
State Not Applicable, archived
Headers show
Series Add RTC support for the Renesas RZ/G3S SoC | expand

Commit Message

claudiu beznea June 14, 2024, 7:19 a.m. UTC
From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>

The RTC IP (RTCA-3) available on the Renesas RZ/G3S SoC has calendar count
mode and binary count mode (selectable though RCR2.CNTMD) capabilities,
alarm capabilities, clock error correction capabilities. It can generate
alarm, period, carry interrupts.

Add a driver for RTCA-3 IP. The driver implements calendar count mode (as
the conversion b/w RTC and system time is simpler, done with bcd2bin(),
bin2bcd()), read and set time, read and set alarm, read and set
an offset.

Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
---
 MAINTAINERS                     |   8 +
 drivers/rtc/Kconfig             |  10 +
 drivers/rtc/Makefile            |   1 +
 drivers/rtc/rtc-renesas-rtca3.c | 891 ++++++++++++++++++++++++++++++++
 4 files changed, 910 insertions(+)
 create mode 100644 drivers/rtc/rtc-renesas-rtca3.c

Comments

Biju Das June 14, 2024, 7:51 a.m. UTC | #1
Hi Claudiu,

Thanks for the patch.

> -----Original Message-----
> From: Claudiu <claudiu.beznea@tuxon.dev>
> Sent: Friday, June 14, 2024 8:19 AM
> Subject: [PATCH 06/12] rtc: renesas-rtca3: Add driver for RTCA-3 available on Renesas RZ/G3S SoC
> 
> From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
> 
> The RTC IP (RTCA-3) available on the Renesas RZ/G3S SoC has calendar count mode and binary count
> mode (selectable though RCR2.CNTMD) capabilities, alarm capabilities, clock error correction
> capabilities. It can generate alarm, period, carry interrupts.
> 
> Add a driver for RTCA-3 IP. The driver implements calendar count mode (as the conversion b/w RTC
> and system time is simpler, done with bcd2bin(), bin2bcd()), read and set time, read and set alarm,
> read and set an offset.
> 
> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
> ---
>  MAINTAINERS                     |   8 +
>  drivers/rtc/Kconfig             |  10 +
>  drivers/rtc/Makefile            |   1 +
>  drivers/rtc/rtc-renesas-rtca3.c | 891 ++++++++++++++++++++++++++++++++
>  4 files changed, 910 insertions(+)
>  create mode 100644 drivers/rtc/rtc-renesas-rtca3.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 670b8201973b..0b4bf350c416 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -19173,6 +19173,14 @@ S:	Supported
>  F:	Documentation/devicetree/bindings/timer/renesas,rz-mtu3.yaml
>  F:	drivers/counter/rz-mtu3-cnt.c
> 
> +RENESAS RZ/G3S RTC DRIVER
Maybe make it generic "RENESAS RTCA3 RTC DRIVER" as it is an IP
can be used in future SoCs??

> +M:	Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
> +L:	linux-rtc@vger.kernel.org
> +L:	linux-renesas-soc@vger.kernel.org
> +S:	Supported
> +F:	Documentation/devicetree/bindings/rtc/renesas,rzg3s-rtc.yaml
Make generic name "renesas,rtca3-rtc.yaml??

Cheers,
Biju

> +F:	drivers/rtc/rtc-renesas-rtca3.c
> +
>  RENESAS RZ/N1 A5PSW SWITCH DRIVER
>  M:	Clément Léger <clement.leger@bootlin.com>
>  L:	linux-renesas-soc@vger.kernel.org
> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig index 2a95b05982ad..3b29b35e48e0 100644
> --- a/drivers/rtc/Kconfig
> +++ b/drivers/rtc/Kconfig
> @@ -1978,6 +1978,16 @@ config RTC_DRV_MA35D1
>  	   This driver can also be built as a module, if so, the module
>  	   will be called "rtc-ma35d1".
> 
> +config RTC_DRV_RENESAS_RTCA3
> +	tristate "Renesas RTCA-3 RTC"
> +	depends on ARCH_RENESAS
> +	help
> +	  If you say yes here you get support for the Renesas RTCA-3 RTC
> +	  available on the Renesas RZ/G3S SoC.
> +
> +	  This driver can also be built as a module, if so, the module
> +	  will be called "rtc-rtca3".
> +
>  comment "HID Sensor RTC drivers"
> 
>  config RTC_DRV_HID_SENSOR_TIME
> diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile index 3004e372f25f..52844f13b247 100644
> --- a/drivers/rtc/Makefile
> +++ b/drivers/rtc/Makefile
> @@ -157,6 +157,7 @@ obj-$(CONFIG_RTC_DRV_RX8025)	+= rtc-rx8025.o
>  obj-$(CONFIG_RTC_DRV_RX8111)	+= rtc-rx8111.o
>  obj-$(CONFIG_RTC_DRV_RX8581)	+= rtc-rx8581.o
>  obj-$(CONFIG_RTC_DRV_RZN1)	+= rtc-rzn1.o
> +obj-$(CONFIG_RTC_DRV_RENESAS_RTCA3)	+= rtc-renesas-rtca3.o
>  obj-$(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-renesas-rtca3.c b/drivers/rtc/rtc-renesas-rtca3.c new file mode 100644
> index 000000000000..e2edf12d0c54
> --- /dev/null
> +++ b/drivers/rtc/rtc-renesas-rtca3.c
> @@ -0,0 +1,891 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * On-Chip RTC Support available on RZ/G3S SoC
> + *
> + * Copyright (C) 2024 Renesas Electronics Corp.
> + */
> +#include <linux/bcd.h>
> +#include <linux/clk.h>
> +#include <linux/completion.h>
> +#include <linux/delay.h>
> +#include <linux/iopoll.h>
> +#include <linux/interrupt.h>
> +#include <linux/jiffies.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/rtc.h>
> +
> +/* Counter registers. */
> +#define RTCA3_RSECCNT			0x2
> +#define RTCA3_RSECCNT_SEC		GENMASK(6, 0)
> +#define RTCA3_RMINCNT			0x4
> +#define RTCA3_RMINCNT_MIN		GENMASK(6, 0)
> +#define RTCA3_RHRCNT			0x6
> +#define RTCA3_RHRCNT_HR			GENMASK(5, 0)
> +#define RTCA3_RHRCNT_PM			BIT(6)
> +#define RTCA3_RWKCNT			0x8
> +#define RTCA3_RWKCNT_WK			GENMASK(2, 0)
> +#define RTCA3_RDAYCNT			0xa
> +#define RTCA3_RDAYCNT_DAY		GENMASK(5, 0)
> +#define RTCA3_RMONCNT			0xc
> +#define RTCA3_RMONCNT_MONTH		GENMASK(4, 0)
> +#define RTCA3_RYRCNT			0xe
> +#define RTCA3_RYRCNT_YEAR		GENMASK(7, 0)
> +
> +/* Alarm registers. */
> +#define RTCA3_RSECAR			0x10
> +#define RTCA3_RSECAR_SEC		GENMASK(6, 0)
> +#define RTCA3_RMINAR			0x12
> +#define RTCA3_RMINAR_MIN		GENMASK(6, 0)
> +#define RTCA3_RHRAR			0x14
> +#define RTCA3_RHRAR_HR			GENMASK(5, 0)
> +#define RTCA3_RHRAR_PM			BIT(6)
> +#define RTCA3_RWKAR			0x16
> +#define RTCA3_RWKAR_DAYW		GENMASK(2, 0)
> +#define RTCA3_RDAYAR			0x18
> +#define RTCA3_RDAYAR_DATE		GENMASK(5, 0)
> +#define RTCA3_RMONAR			0x1a
> +#define RTCA3_RMONAR_MON		GENMASK(4, 0)
> +#define RTCA3_RYRAR			0x1c
> +#define RTCA3_RYRAR_YR			GENMASK(7, 0)
> +#define RTCA3_RYRAREN			0x1e
> +
> +/* Alarm enable bit (for all alarm registers). */
> +#define RTCA3_AR_ENB			BIT(7)
> +
> +/* Control registers. */
> +#define RTCA3_RCR1			0x22
> +#define RTCA3_RCR1_AIE			BIT(0)
> +#define RTCA3_RCR1_CIE			BIT(1)
> +#define RTCA3_RCR1_PIE			BIT(2)
> +#define RTCA3_RCR1_PES			GENMASK(7, 4)
> +#define RTCA3_RCR1_PES_1_64_SEC		0x8
> +#define RTCA3_RCR2			0x24
> +#define RTCA3_RCR2_START		BIT(0)
> +#define RTCA3_RCR2_RESET		BIT(1)
> +#define RTCA3_RCR2_AADJE		BIT(4)
> +#define RTCA3_RCR2_ADJP			BIT(5)
> +#define RTCA3_RCR2_HR24			BIT(6)
> +#define RTCA3_RCR2_CNTMD		BIT(7)
> +#define RTCA3_RSR			0x20
> +#define RTCA3_RSR_AF			BIT(0)
> +#define RTCA3_RSR_CF			BIT(1)
> +#define RTCA3_RSR_PF			BIT(2)
> +#define RTCA3_RADJ			0x2e
> +#define RTCA3_RADJ_ADJ			GENMASK(5, 0)
> +#define RTCA3_RADJ_ADJ_MAX		0x3f
> +#define RTCA3_RADJ_PMADJ		GENMASK(7, 6)
> +#define RTCA3_RADJ_PMADJ_NONE		0
> +#define RTCA3_RADJ_PMADJ_ADD		1
> +#define RTCA3_RADJ_PMADJ_SUB		2
> +
> +/* Polling operation timeouts. */
> +#define RTCA3_DEFAULT_TIMEOUT_US	150
> +#define RTCA3_IRQSET_TIMEOUT_US		5000
> +#define RTCA3_START_TIMEOUT_US		150000
> +#define RTCA3_RESET_TIMEOUT_US		200000
> +
> +/**
> + * enum rtca3_alrm_set_step - RTCA3 alarm set steps
> + * @RTCA3_ALRM_SSTEP_DONE: alarm setup done step
> + * @RTCA3_ALRM_SSTEP_IRQ: two 1/64 periodic IRQs were generated step
> + * @RTCA3_ALRM_SSTEP_INIT: alarm setup initialization step  */ enum
> +rtca3_alrm_set_step {
> +	RTCA3_ALRM_SSTEP_DONE = 0,
> +	RTCA3_ALRM_SSTEP_IRQ = 1,
> +	RTCA3_ALRM_SSTEP_INIT = 3,
> +};
> +
> +/**
> + * struct rtca3_ppb_per_cycle - PPB per cycle
> + * @ten_sec: PPB per cycle in 10 seconds adjutment mode
> + * @sixty_sec: PPB per cycle in 60 seconds adjustment mode  */ struct
> +rtca3_ppb_per_cycle {
> +	int ten_sec;
> +	int sixty_sec;
> +};
> +
> +/**
> + * struct rtca3_priv - RTCA3 private data structure
> + * @base: base address
> + * @clk: RTC clock
> + * @rtc_dev: RTC device
> + * @set_alarm_completion: alarm setup completion
> + * @alrm_sstep: alarm setup step (see enum rtca3_alrm_set_step)
> + * @lock: device lock
> + * @ppb: ppb per cycle for each the available adjustment modes
> + * @wakeup_irq: wakeup IRQ
> + */
> +struct rtca3_priv {
> +	void __iomem *base;
> +	struct clk *clk;
> +	struct rtc_device *rtc_dev;
> +	struct completion set_alarm_completion;
> +	atomic_t alrm_sstep;
> +	spinlock_t lock;
> +	struct rtca3_ppb_per_cycle ppb;
> +	int wakeup_irq;
> +};
> +
> +static void rtca3_byte_update_bits(struct rtca3_priv *priv, u8 off, u8
> +mask, u8 val) {
> +	u8 tmp;
> +
> +	tmp = readb(priv->base + off);
> +	tmp &= ~(mask);
> +	tmp |= (val & mask);
> +	writeb(tmp, priv->base + off);
> +}
> +
> +static u8 rtca3_alarm_handler_helper(struct rtca3_priv *priv) {
> +	u8 val, pending;
> +
> +	val = readb(priv->base + RTCA3_RSR);
> +	pending = val & RTCA3_RSR_AF;
> +	writeb(val & ~pending, priv->base + RTCA3_RSR);
> +
> +	if (pending)
> +		rtc_update_irq(priv->rtc_dev, 1, RTC_AF | RTC_IRQF);
> +
> +	return pending;
> +}
> +
> +static irqreturn_t rtca3_alarm_handler(int irq, void *dev_id) {
> +	struct rtca3_priv *priv = dev_id;
> +	u8 pending;
> +
> +	spin_lock(&priv->lock);
> +	pending = rtca3_alarm_handler_helper(priv);
> +	spin_unlock(&priv->lock);
> +
> +	return IRQ_RETVAL(pending);
> +}
> +
> +static irqreturn_t rtca3_periodic_handler(int irq, void *dev_id) {
> +	struct rtca3_priv *priv = dev_id;
> +	u8 val, pending;
> +
> +	spin_lock(&priv->lock);
> +
> +	val = readb(priv->base + RTCA3_RSR);
> +	pending = val & RTCA3_RSR_PF;
> +
> +	if (pending) {
> +		writeb(val & ~pending, priv->base + RTCA3_RSR);
> +
> +		if (atomic_read(&priv->alrm_sstep) > RTCA3_ALRM_SSTEP_IRQ) {
> +			/* Alarm setup in progress. */
> +			atomic_dec(&priv->alrm_sstep);
> +
> +			if (atomic_read(&priv->alrm_sstep) == RTCA3_ALRM_SSTEP_IRQ) {
> +				/*
> +				 * We got 2 * 1/64 periodic interrupts. Disable
> +				 * interrupt and let alarm setup continue.
> +				 */
> +				rtca3_byte_update_bits(priv, RTCA3_RCR1,
> +						       RTCA3_RCR1_PIE, 0);
> +				readb_poll_timeout_atomic(priv->base + RTCA3_RCR1, val,
> +							  !(val & RTCA3_RCR1_PIE),
> +							  10, RTCA3_DEFAULT_TIMEOUT_US);
> +				complete(&priv->set_alarm_completion);
> +			}
> +		}
> +	}
> +
> +	spin_unlock(&priv->lock);
> +
> +	return IRQ_RETVAL(pending);
> +}
> +
> +static void rtca3_prepare_cntalrm_regs_for_read(struct rtca3_priv
> +*priv, bool cnt) {
> +	/* Offset b/w time and alarm registers. */
> +	u8 offset = cnt ? 0 : 0xe;
> +
> +	/*
> +	 * According to HW manual (section 22.6.4. Notes on writing to and
> +	 * reading from registers) after writing to count registers, alarm
> +	 * registers, year alarm enable register, bits RCR2.AADJE, AADJP,
> +	 * and HR24 register, we need to do 3 empty reads before being
> +	 * able to fetch the registers content.
> +	 */
> +	for (u8 i = 0; i < 3; i++) {
> +		readb(priv->base + RTCA3_RSECCNT + offset);
> +		readb(priv->base + RTCA3_RMINCNT + offset);
> +		readb(priv->base + RTCA3_RHRCNT  + offset);
> +		readb(priv->base + RTCA3_RWKCNT  + offset);
> +		readb(priv->base + RTCA3_RDAYCNT + offset);
> +		readw(priv->base + RTCA3_RYRCNT  + offset);
> +		if (!cnt)
> +			readb(priv->base + RTCA3_RYRAREN);
> +	}
> +}
> +
> +static int rtca3_read_time(struct device *dev, struct rtc_time *tm) {
> +	struct rtca3_priv *priv = dev_get_drvdata(dev);
> +	u8 sec, min, hour, wday, mday, month, tmp;
> +	unsigned long flags;
> +	u8 trials = 0;
> +	int ret = 0;
> +	u32 year100;
> +	u16 year;
> +
> +	spin_lock_irqsave(&priv->lock, flags);
> +
> +	tmp = readb(priv->base + RTCA3_RCR2);
> +	if (!(tmp & RTCA3_RCR2_START)) {
> +		ret = -EINVAL;
> +		goto unlock;
> +	}
> +
> +	do {
> +		/* Clear carry interrupt. */
> +		rtca3_byte_update_bits(priv, RTCA3_RSR, RTCA3_RSR_CF, 0);
> +
> +		/* Read counters. */
> +		sec = readb(priv->base + RTCA3_RSECCNT);
> +		min = readb(priv->base + RTCA3_RMINCNT);
> +		hour = readb(priv->base + RTCA3_RHRCNT);
> +		wday = readb(priv->base + RTCA3_RWKCNT);
> +		mday = readb(priv->base + RTCA3_RDAYCNT);
> +		month = readb(priv->base + RTCA3_RMONCNT);
> +		year = readw(priv->base + RTCA3_RYRCNT);
> +
> +		tmp = readb(priv->base + RTCA3_RSR);
> +
> +		/*
> +		 * We cannot generate carries due to reading 64Hz counter as
> +		 * the driver doesn't implement carry, thus, carries will be
> +		 * generated once per seconds. Add a timeout of 5 trials here
> +		 * to avoid infinite loop, if any.
> +		 */
> +	} while ((tmp & RTCA3_RSR_CF) && ++trials < 5);
> +
> +	if (trials >= 5) {
> +		ret = -ETIMEDOUT;
> +		goto unlock;
> +	}
> +
> +	tm->tm_sec = bcd2bin(FIELD_GET(RTCA3_RSECCNT_SEC, sec));
> +	tm->tm_min = bcd2bin(FIELD_GET(RTCA3_RMINCNT_MIN, min));
> +	tm->tm_hour = bcd2bin(FIELD_GET(RTCA3_RHRCNT_HR, hour));
> +	if (hour & RTCA3_RHRCNT_PM)
> +		tm->tm_hour += 12;
> +	tm->tm_wday = bcd2bin(FIELD_GET(RTCA3_RWKCNT_WK, wday));
> +	tm->tm_mday = bcd2bin(FIELD_GET(RTCA3_RDAYCNT_DAY, mday));
> +	tm->tm_mon = bcd2bin(FIELD_GET(RTCA3_RMONCNT_MONTH, month)) - 1;
> +	year = FIELD_GET(RTCA3_RYRCNT_YEAR, year);
> +	year100 = bcd2bin((year == 0x99) ? 0x19 : 0x20);
> +	tm->tm_year = (year100 * 100 + bcd2bin(year)) - 1900;
> +
> +unlock:
> +	spin_unlock_irqrestore(&priv->lock, flags);
> +
> +	return ret;
> +}
> +
> +static int rtca3_set_time(struct device *dev, struct rtc_time *tm) {
> +	struct rtca3_priv *priv = dev_get_drvdata(dev);
> +	unsigned long flags;
> +	u8 rcr2, tmp;
> +	int ret;
> +
> +	spin_lock_irqsave(&priv->lock, flags);
> +
> +	/* Stop the RTC. */
> +	rcr2 = readb(priv->base + RTCA3_RCR2);
> +	writeb(rcr2 & ~RTCA3_RCR2_START, priv->base + RTCA3_RCR2);
> +	ret = readb_poll_timeout_atomic(priv->base + RTCA3_RCR2, tmp,
> +					!(tmp & RTCA3_RCR2_START),
> +					10, RTCA3_DEFAULT_TIMEOUT_US);
> +	if (ret)
> +		goto unlock;
> +
> +	/* Update time. */
> +	writeb(bin2bcd(tm->tm_sec), priv->base + RTCA3_RSECCNT);
> +	writeb(bin2bcd(tm->tm_min), priv->base + RTCA3_RMINCNT);
> +	if (tm->tm_hour > 12)
> +		writeb(RTCA3_RHRCNT_PM | bin2bcd(tm->tm_hour - 12), priv->base + RTCA3_RHRCNT);
> +	else
> +		writeb(bin2bcd(tm->tm_hour), priv->base + RTCA3_RHRCNT);
> +	writeb(bin2bcd(tm->tm_wday), priv->base + RTCA3_RWKCNT);
> +	writeb(bin2bcd(tm->tm_mday), priv->base + RTCA3_RDAYCNT);
> +	writeb(bin2bcd(tm->tm_mon + 1), priv->base + RTCA3_RMONCNT);
> +	writew(bin2bcd(tm->tm_year % 100), priv->base + RTCA3_RYRCNT);
> +
> +	/* Make sure we can read back the counters. */
> +	rtca3_prepare_cntalrm_regs_for_read(priv, true);
> +
> +	/* Start RTC. */
> +	writeb(rcr2 | RTCA3_RCR2_START, priv->base + RTCA3_RCR2);
> +	ret = readb_poll_timeout_atomic(priv->base + RTCA3_RCR2, tmp,
> +					(tmp & RTCA3_RCR2_START),
> +					10, RTCA3_DEFAULT_TIMEOUT_US);
> +
> +unlock:
> +	spin_unlock_irqrestore(&priv->lock, flags);
> +
> +	return ret;
> +}
> +
> +static int rtca3_alarm_irq_enable_helper(struct rtca3_priv *priv,
> +					 unsigned int enabled)
> +{
> +	u8 tmp, mask;
> +
> +	if (enabled) {
> +		rtca3_byte_update_bits(priv, RTCA3_RSR, RTCA3_RSR_AF, 0);
> +		mask = RTCA3_RCR1_AIE;
> +	} else {
> +		mask = 0;
> +	}
> +
> +	rtca3_byte_update_bits(priv, RTCA3_RCR1, RTCA3_RCR1_AIE, mask);
> +	return readb_poll_timeout_atomic(priv->base + RTCA3_RCR1, tmp,
> +					 ((tmp & RTCA3_RCR1_AIE) == mask),
> +					 10, RTCA3_IRQSET_TIMEOUT_US);
> +}
> +
> +static int rtca3_alarm_irq_enable(struct device *dev, unsigned int
> +enabled) {
> +	struct rtca3_priv *priv = dev_get_drvdata(dev);
> +	unsigned long flags;
> +	int ret;
> +
> +	spin_lock_irqsave(&priv->lock, flags);
> +	ret = rtca3_alarm_irq_enable_helper(priv, enabled);
> +	spin_unlock_irqrestore(&priv->lock, flags);
> +
> +	return ret;
> +}
> +
> +static int rtca3_read_alarm(struct device *dev, struct rtc_wkalrm
> +*wkalrm) {
> +	struct rtca3_priv *priv = dev_get_drvdata(dev);
> +	u8 sec, min, hour, wday, mday, month;
> +	struct rtc_time *tm = &wkalrm->time;
> +	unsigned long flags;
> +	u32 year100;
> +	u16 year;
> +
> +	spin_lock_irqsave(&priv->lock, flags);
> +
> +	sec = readb(priv->base + RTCA3_RSECAR);
> +	min = readb(priv->base + RTCA3_RMINAR);
> +	hour = readb(priv->base + RTCA3_RHRAR);
> +	wday = readb(priv->base + RTCA3_RWKAR);
> +	mday = readb(priv->base + RTCA3_RDAYAR);
> +	month = readb(priv->base + RTCA3_RMONAR);
> +	year = readw(priv->base + RTCA3_RYRAR);
> +
> +	tm->tm_sec = bcd2bin(FIELD_GET(RTCA3_RSECAR_SEC, sec));
> +	tm->tm_min = bcd2bin(FIELD_GET(RTCA3_RMINAR_MIN, min));
> +	tm->tm_hour = bcd2bin(FIELD_GET(RTCA3_RHRAR_HR, hour));
> +	if (hour & RTCA3_RHRAR_PM)
> +		tm->tm_hour += 12;
> +	tm->tm_wday = bcd2bin(FIELD_GET(RTCA3_RWKAR_DAYW, wday));
> +	tm->tm_mday = bcd2bin(FIELD_GET(RTCA3_RDAYAR_DATE, mday));
> +	tm->tm_mon = bcd2bin(FIELD_GET(RTCA3_RMONAR_MON, month)) - 1;
> +	year = FIELD_GET(RTCA3_RYRAR_YR, year);
> +	year100 = bcd2bin((year == 0x99) ? 0x19 : 0x20);
> +	tm->tm_year = (year100 * 100 + bcd2bin(year)) - 1900;
> +
> +	wkalrm->enabled = !!(readb(priv->base + RTCA3_RCR1) & RTCA3_RCR1_AIE);
> +
> +	spin_unlock_irqrestore(&priv->lock, flags);
> +
> +	return 0;
> +}
> +
> +static int rtca3_set_alarm(struct device *dev, struct rtc_wkalrm
> +*wkalrm) {
> +	struct rtca3_priv *priv = dev_get_drvdata(dev);
> +	struct rtc_time *tm = &wkalrm->time;
> +	unsigned long flags;
> +	u8 rcr1, tmp;
> +	int ret;
> +
> +	spin_lock_irqsave(&priv->lock, flags);
> +
> +	tmp = readb(priv->base + RTCA3_RCR2);
> +	if (!(tmp & RTCA3_RCR2_START)) {
> +		ret = -EPERM;
> +		goto unlock;
> +	}
> +
> +	/* Disable AIE to prevent false interrupts. */
> +	rcr1 = readb(priv->base + RTCA3_RCR1);
> +	rcr1 &= ~RTCA3_RCR1_AIE;
> +	writeb(rcr1, priv->base + RTCA3_RCR1);
> +	ret = readb_poll_timeout_atomic(priv->base + RTCA3_RCR1, tmp,
> +					!(tmp & RTCA3_RCR1_AIE),
> +					10, RTCA3_DEFAULT_TIMEOUT_US);
> +	if (ret)
> +		goto unlock;
> +
> +	/* Set the time and enable the alarm. */
> +	writeb(RTCA3_AR_ENB | bin2bcd(tm->tm_sec), priv->base + RTCA3_RSECAR);
> +	writeb(RTCA3_AR_ENB | bin2bcd(tm->tm_min), priv->base + RTCA3_RMINAR);
> +	if (tm->tm_hour > 12) {
> +		writeb(RTCA3_AR_ENB | RTCA3_RHRAR_PM | bin2bcd(tm->tm_hour - 12),
> +		       priv->base + RTCA3_RHRAR);
> +	} else {
> +		writeb(RTCA3_AR_ENB | bin2bcd(tm->tm_hour), priv->base + RTCA3_RHRAR);
> +	}
> +	writeb(RTCA3_AR_ENB | bin2bcd(tm->tm_wday), priv->base + RTCA3_RWKAR);
> +	writeb(RTCA3_AR_ENB | bin2bcd(tm->tm_mday), priv->base + RTCA3_RDAYAR);
> +	writeb(RTCA3_AR_ENB | bin2bcd(tm->tm_mon + 1), priv->base +
> +RTCA3_RMONAR);
> +
> +	writew(bin2bcd(tm->tm_year % 100), priv->base + RTCA3_RYRAR);
> +	writeb(RTCA3_AR_ENB, priv->base + RTCA3_RYRAREN);
> +
> +	/* Make sure we can read back the counters. */
> +	rtca3_prepare_cntalrm_regs_for_read(priv, false);
> +
> +	/* Need to wait for 2 * 1/64 periodic interrupts to be generated. */
> +	atomic_set(&priv->alrm_sstep, RTCA3_ALRM_SSTEP_INIT);
> +	reinit_completion(&priv->set_alarm_completion);
> +
> +	/* Enable periodic interrupt. */
> +	rcr1 |= RTCA3_RCR1_PIE;
> +	writeb(rcr1, priv->base + RTCA3_RCR1);
> +	ret = readb_poll_timeout_atomic(priv->base + RTCA3_RCR1, tmp,
> +					(tmp & RTCA3_RCR1_PIE),
> +					10, RTCA3_IRQSET_TIMEOUT_US);
> +
> +	spin_unlock_irqrestore(&priv->lock, flags);
> +
> +	if (ret)
> +		goto setup_failed;
> +
> +	/* Wait for the 2 * 1/64 periodic interrupts. */
> +	ret = wait_for_completion_interruptible_timeout(&priv->set_alarm_completion,
> +							msecs_to_jiffies(500));
> +	if (ret <= 0) {
> +		ret = -ETIMEDOUT;
> +		goto setup_failed;
> +	}
> +
> +	spin_lock_irqsave(&priv->lock, flags);
> +
> +	ret = rtca3_alarm_irq_enable_helper(priv, wkalrm->enabled);
> +	atomic_set(&priv->alrm_sstep, RTCA3_ALRM_SSTEP_DONE);
> +
> +unlock:
> +	spin_unlock_irqrestore(&priv->lock, flags);
> +
> +	return ret;
> +
> +setup_failed:
> +	spin_lock_irqsave(&priv->lock, flags);
> +	/*
> +	 * Disable PIE to avoid interrupt storm in case HW needed more than
> +	 * specified timeout for setup.
> +	 */
> +	writeb(rcr1 & ~RTCA3_RCR1_PIE, priv->base + RTCA3_RCR1);
> +	readb_poll_timeout_atomic(priv->base + RTCA3_RCR1, tmp, !(tmp & ~RTCA3_RCR1_PIE),
> +				  10, RTCA3_DEFAULT_TIMEOUT_US);
> +	atomic_set(&priv->alrm_sstep, RTCA3_ALRM_SSTEP_DONE);
> +	spin_unlock_irqrestore(&priv->lock, flags);
> +
> +	return ret;
> +}
> +
> +static int rtca3_read_offset(struct device *dev, long *offset) {
> +	struct rtca3_priv *priv = dev_get_drvdata(dev);
> +	u8 val, radj, cycles;
> +	unsigned long flags;
> +	u32 ppb_per_cycle;
> +
> +	spin_lock_irqsave(&priv->lock, flags);
> +	radj = readb(priv->base + RTCA3_RADJ);
> +	val = readb(priv->base + RTCA3_RCR2);
> +	spin_unlock_irqrestore(&priv->lock, flags);
> +
> +	cycles = FIELD_GET(RTCA3_RADJ_ADJ, radj);
> +
> +	if (!cycles) {
> +		*offset = 0;
> +		return 0;
> +	}
> +
> +	if (val & RTCA3_RCR2_ADJP)
> +		ppb_per_cycle = priv->ppb.ten_sec;
> +	else
> +		ppb_per_cycle = priv->ppb.sixty_sec;
> +
> +	*offset = cycles * ppb_per_cycle;
> +	val = FIELD_GET(RTCA3_RADJ_PMADJ, radj);
> +	if (val == RTCA3_RADJ_PMADJ_SUB)
> +		*offset = -(*offset);
> +
> +	return 0;
> +}
> +
> +static int rtca3_set_offset(struct device *dev, long offset) {
> +	struct rtca3_priv *priv = dev_get_drvdata(dev);
> +	int cycles, cycles10, cycles60;
> +	unsigned long flags;
> +	u8 radj, adjp, tmp;
> +	int ret;
> +
> +	/*
> +	 * Automatic time error adjustment could be set at intervals of 10
> +	 * or 60 seconds.
> +	 */
> +	cycles10 = DIV_ROUND_CLOSEST(offset, priv->ppb.ten_sec);
> +	cycles60 = DIV_ROUND_CLOSEST(offset, priv->ppb.sixty_sec);
> +
> +	/* We can set b/w 1 and 63 clock cycles. */
> +	if (cycles60 >= -RTCA3_RADJ_ADJ_MAX &&
> +	    cycles60 <= RTCA3_RADJ_ADJ_MAX) {
> +		cycles = cycles60;
> +		adjp = 0;
> +	} else if (cycles10 >= -RTCA3_RADJ_ADJ_MAX &&
> +		   cycles10 <= RTCA3_RADJ_ADJ_MAX) {
> +		cycles = cycles10;
> +		adjp = RTCA3_RCR2_ADJP;
> +	} else {
> +		return -ERANGE;
> +	}
> +
> +	radj = FIELD_PREP(RTCA3_RADJ_ADJ, abs(cycles));
> +	if (!cycles)
> +		radj |= FIELD_PREP(RTCA3_RADJ_PMADJ, RTCA3_RADJ_PMADJ_NONE);
> +	else if (cycles > 0)
> +		radj |= FIELD_PREP(RTCA3_RADJ_PMADJ, RTCA3_RADJ_PMADJ_ADD);
> +	else
> +		radj |= FIELD_PREP(RTCA3_RADJ_PMADJ, RTCA3_RADJ_PMADJ_SUB);
> +
> +	spin_lock_irqsave(&priv->lock, flags);
> +
> +	tmp = readb(priv->base + RTCA3_RCR2);
> +
> +	if ((tmp & RTCA3_RCR2_ADJP) != adjp) {
> +		/* RADJ.PMADJ need to be set to zero before setting RCR2.ADJP. */
> +		writeb(0, priv->base + RTCA3_RADJ);
> +		ret = readb_poll_timeout_atomic(priv->base + RTCA3_RADJ, tmp, !tmp,
> +						10, RTCA3_DEFAULT_TIMEOUT_US);
> +		if (ret)
> +			goto unlock;
> +
> +		rtca3_byte_update_bits(priv, RTCA3_RCR2, RTCA3_RCR2_ADJP, adjp);
> +		ret = readb_poll_timeout_atomic(priv->base + RTCA3_RCR2, tmp,
> +						((tmp & RTCA3_RCR2_ADJP) == adjp),
> +						10, RTCA3_DEFAULT_TIMEOUT_US);
> +		if (ret)
> +			goto unlock;
> +	}
> +
> +	writeb(radj, priv->base + RTCA3_RADJ);
> +	ret = readb_poll_timeout_atomic(priv->base + RTCA3_RADJ, tmp, (tmp == radj),
> +					10, RTCA3_DEFAULT_TIMEOUT_US);
> +unlock:
> +	spin_unlock_irqrestore(&priv->lock, flags);
> +
> +	return ret;
> +}
> +
> +static const struct rtc_class_ops rtca3_ops = {
> +	.read_time = rtca3_read_time,
> +	.set_time = rtca3_set_time,
> +	.read_alarm = rtca3_read_alarm,
> +	.set_alarm = rtca3_set_alarm,
> +	.alarm_irq_enable = rtca3_alarm_irq_enable,
> +	.set_offset = rtca3_set_offset,
> +	.read_offset = rtca3_read_offset,
> +};
> +
> +static int rtca3_initial_setup(struct rtca3_priv *priv) {
> +	unsigned long osc32k_rate;
> +	u8 pes, tmp, mask;
> +	u32 sleep_us;
> +	int ret;
> +
> +	osc32k_rate = clk_get_rate(priv->clk);
> +	if (!osc32k_rate)
> +		return -EINVAL;
> +
> +	sleep_us = DIV_ROUND_UP_ULL(1000000ULL, osc32k_rate) * 6;
> +
> +	priv->ppb.ten_sec = DIV_ROUND_CLOSEST_ULL(1000000000ULL, (osc32k_rate * 10));
> +	priv->ppb.sixty_sec = DIV_ROUND_CLOSEST_ULL(1000000000ULL,
> +(osc32k_rate * 60));
> +
> +	/*
> +	 * According to HW manual (section 22.4.2. Clock and count mode setting procedure)
> +	 * we need to wait at least 6 cycles of the 32KHz clock after clock was enabled.
> +	 */
> +	usleep_range(sleep_us, sleep_us + 10);
> +
> +	/* Disable alarm and carry interrupts. */
> +	mask = RTCA3_RCR1_AIE | RTCA3_RCR1_CIE;
> +	rtca3_byte_update_bits(priv, RTCA3_RCR1, mask, 0);
> +	ret = readb_poll_timeout(priv->base + RTCA3_RCR1, tmp, !(tmp & mask),
> +				 10, RTCA3_DEFAULT_TIMEOUT_US);
> +	if (ret)
> +		return ret;
> +
> +	/*
> +	 * Stop the RTC and set to 12 hours mode and calendar count mode.
> +	 * RCR2.START initial value is undefined so we need to stop here
> +	 * all the time.
> +	 */
> +	mask = RTCA3_RCR2_START | RTCA3_RCR2_HR24 | RTCA3_RCR2_CNTMD;
> +	writeb(0, priv->base + RTCA3_RCR2);
> +	ret = readb_poll_timeout(priv->base + RTCA3_RCR2, tmp, !(tmp & mask),
> +				 10, RTCA3_DEFAULT_TIMEOUT_US);
> +	if (ret)
> +		return ret;
> +
> +	/* Execute reset and wait for reset and calendar count mode to be applied. */
> +	mask = RTCA3_RCR2_RESET | RTCA3_RCR2_CNTMD;
> +	writeb(RTCA3_RCR2_RESET, priv->base + RTCA3_RCR2);
> +	ret = readb_poll_timeout(priv->base + RTCA3_RCR2, tmp, !(tmp & mask),
> +				 10, RTCA3_RESET_TIMEOUT_US);
> +	if (ret)
> +		return ret;
> +
> +	/*
> +	 * According to HW manual (section 22.6.3. Notes on writing to and reading
> +	 * from registers) after reset we need to wait 6 clock cycles before
> +	 * writing to RTC registers.
> +	 */
> +	usleep_range(sleep_us, sleep_us + 10);
> +
> +	/* Set no adjustment. */
> +	writeb(0, priv->base + RTCA3_RADJ);
> +	ret = readb_poll_timeout(priv->base + RTCA3_RADJ, tmp, !tmp, 10,
> +				 RTCA3_DEFAULT_TIMEOUT_US);
> +
> +	/* Start the RTC and enable automatic time error adjustment. */
> +	mask = RTCA3_RCR2_START | RTCA3_RCR2_AADJE;
> +	writeb(RTCA3_RCR2_START | RTCA3_RCR2_AADJE, priv->base + RTCA3_RCR2);
> +	ret = readb_poll_timeout(priv->base + RTCA3_RCR2, tmp, ((tmp & mask) == mask),
> +				 10, RTCA3_START_TIMEOUT_US);
> +	if (ret)
> +		return ret;
> +
> +	/*
> +	 * According to HW manual (section 22.6.4. Notes on writing to and reading
> +	 * from registers) we need to wait 1/128 seconds while the clock is operating
> +	 * (RCR2.START bit = 1) to be able to read the counters after a return from
> +	 * reset.
> +	 */
> +	usleep_range(8000, 9000);
> +
> +	/* Set period interrupt to 1/64 seconds. It is necessary for alarm setup. */
> +	pes = FIELD_PREP(RTCA3_RCR1_PES, RTCA3_RCR1_PES_1_64_SEC);
> +	rtca3_byte_update_bits(priv, RTCA3_RCR1, RTCA3_RCR1_PES, pes);
> +	return readb_poll_timeout(priv->base + RTCA3_RCR1, tmp, ((tmp & RTCA3_RCR1_PES) == pes),
> +				  10, RTCA3_DEFAULT_TIMEOUT_US);
> +}
> +
> +static int rtca3_request_irqs(struct platform_device *pdev, struct
> +rtca3_priv *priv) {
> +	struct device *dev = &pdev->dev;
> +	int ret, irq;
> +
> +	irq = platform_get_irq_byname(pdev, "alarm");
> +	if (irq < 0)
> +		return dev_err_probe(dev, irq, "Failed to get alarm IRQ!\n");
> +
> +	ret = devm_request_irq(dev, irq, rtca3_alarm_handler, 0, "rtca3-alarm", priv);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "Failed to request alarm IRQ!\n");
> +	priv->wakeup_irq = irq;
> +
> +	irq = platform_get_irq_byname(pdev, "period");
> +	if (irq < 0)
> +		return dev_err_probe(dev, irq, "Failed to get period IRQ!\n");
> +
> +	ret = devm_request_irq(dev, irq, rtca3_periodic_handler, 0, "rtca3-period", priv);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "Failed to request period IRQ!\n");
> +
> +	/*
> +	 * Driver doesn't implement carry handler. Just get the IRQ here
> +	 * for backward compatibility, in case carry support will be added later.
> +	 */
> +	irq = platform_get_irq_byname(pdev, "carry");
> +	if (irq < 0)
> +		return dev_err_probe(dev, irq, "Failed to get carry IRQ!\n");
> +
> +	return 0;
> +}
> +
> +static int rtca3_probe(struct platform_device *pdev) {
> +	struct device *dev = &pdev->dev;
> +	struct rtca3_priv *priv;
> +	int ret;
> +
> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	priv->base = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(priv->base))
> +		return PTR_ERR(priv->base);
> +
> +	priv->clk = devm_clk_get_enabled(dev, "counter");
> +	if (IS_ERR(priv->clk))
> +		return PTR_ERR(priv->clk);
> +
> +	platform_set_drvdata(pdev, priv);
> +
> +	spin_lock_init(&priv->lock);
> +	atomic_set(&priv->alrm_sstep, RTCA3_ALRM_SSTEP_DONE);
> +	init_completion(&priv->set_alarm_completion);
> +
> +	ret = rtca3_initial_setup(priv);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "Failed to setup the RTC!\n");
> +
> +	ret = rtca3_request_irqs(pdev, priv);
> +	if (ret)
> +		return ret;
> +
> +	device_init_wakeup(&pdev->dev, 1);
> +
> +	priv->rtc_dev = devm_rtc_allocate_device(&pdev->dev);
> +	if (IS_ERR(priv->rtc_dev))
> +		return PTR_ERR(priv->rtc_dev);
> +
> +	priv->rtc_dev->ops = &rtca3_ops;
> +	priv->rtc_dev->max_user_freq = 256;
> +	priv->rtc_dev->range_min = mktime64(1999, 1, 1, 0, 0, 0);
> +	priv->rtc_dev->range_max = mktime64(2098, 12, 31, 23, 59, 59);
> +
> +	return devm_rtc_register_device(priv->rtc_dev);
> +}
> +
> +static void rtca3_remove(struct platform_device *pdev) {
> +	struct rtca3_priv *priv = platform_get_drvdata(pdev);
> +	u8 tmp, mask = RTCA3_RCR1_AIE | RTCA3_RCR1_PIE;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&priv->lock, flags);
> +
> +	/* Disable alarm, periodic interrupt. */
> +	rtca3_byte_update_bits(priv, RTCA3_RCR1, mask, 0);
> +	readb_poll_timeout_atomic(priv->base + RTCA3_RCR1, tmp, !(tmp & mask),
> +				  10, RTCA3_IRQSET_TIMEOUT_US);
> +
> +	spin_unlock_irqrestore(&priv->lock, flags); }
> +
> +static int __maybe_unused rtca3_suspend(struct device *dev) {
> +	struct rtca3_priv *priv = dev_get_drvdata(dev);
> +
> +	if (!device_may_wakeup(dev))
> +		return 0;
> +
> +	/* Alarm setup in progress. */
> +	if (atomic_read(&priv->alrm_sstep) != RTCA3_ALRM_SSTEP_DONE)
> +		return -EBUSY;
> +
> +	enable_irq_wake(priv->wakeup_irq);
> +
> +	return 0;
> +}
> +
> +static int rtca3_clean_alarm(struct rtca3_priv *priv) {
> +	struct rtc_device *rtc_dev = priv->rtc_dev;
> +	time64_t alarm_time, now;
> +	struct rtc_wkalrm alarm;
> +	unsigned long flags;
> +	struct rtc_time tm;
> +	u8 pending;
> +	int ret;
> +
> +	ret = rtc_read_alarm(rtc_dev, &alarm);
> +	if (ret)
> +		return ret;
> +
> +	if (!alarm.enabled)
> +		return 0;
> +
> +	ret = rtc_read_time(rtc_dev, &tm);
> +	if (ret)
> +		return ret;
> +
> +	alarm_time = rtc_tm_to_time64(&alarm.time);
> +	now = rtc_tm_to_time64(&tm);
> +	if (alarm_time >= now)
> +		return 0;
> +
> +	/*
> +	 * Heuristically, it has been determined that when returning from deep
> +	 * sleep state the RTCA3_RSR.AF is zero even though the alarm expired.
> +	 * Call again the rtc_update_irq() if alarm helper detects this.
> +	 */
> +
> +	spin_lock_irqsave(&priv->lock, flags);
> +	pending = rtca3_alarm_handler_helper(priv);
> +	if (!pending)
> +		rtc_update_irq(priv->rtc_dev, 1, RTC_AF | RTC_IRQF);
> +	spin_unlock_irqrestore(&priv->lock, flags);
> +
> +	return 0;
> +}
> +
> +static int __maybe_unused rtca3_resume(struct device *dev) {
> +	struct rtca3_priv *priv = dev_get_drvdata(dev);
> +
> +	if (!device_may_wakeup(dev))
> +		return 0;
> +
> +	disable_irq_wake(priv->wakeup_irq);
> +
> +	/*
> +	 * According to the HW manual (section 22.6.4 Notes on writing to
> +	 * and reading from registers) we need to wait 1/128 seconds while
> +	 * RCR2.START = 1 to be able to read the counters after a return from low
> +	 * power consumption state.
> +	 */
> +	mdelay(8);
> +
> +	/*
> +	 * The alarm cannot wake the system from deep sleep states. In case
> +	 * we return from deep sleep states and the alarm expired we need
> +	 * to disable it to avoid failures when setting another alarm.
> +	 */
> +	return rtca3_clean_alarm(priv);
> +}
> +
> +static SIMPLE_DEV_PM_OPS(rtca3_pm_ops, rtca3_suspend, rtca3_resume);
> +
> +static const struct of_device_id rtca3_of_match[] = {
> +	{ .compatible = "renesas,rzg3s-rtc", },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, rtca3_of_match);
> +
> +static struct platform_driver rtca3_platform_driver = {
> +	.driver = {
> +		.name = "rtc-rtca3",
> +		.pm = &rtca3_pm_ops,
> +		.of_match_table = rtca3_of_match,
> +	},
> +	.probe = rtca3_probe,
> +	.remove_new = rtca3_remove,
> +};
> +module_platform_driver(rtca3_platform_driver);
> +
> +MODULE_DESCRIPTION("Renesas RTCA-3 RTC driver"); MODULE_AUTHOR("Claudiu
> +Beznea <claudiu.beznea.uj@bp.renesas.com>");
> +MODULE_LICENSE("GPL");
> --
> 2.39.2
>
Alexandre Belloni June 14, 2024, 9:21 a.m. UTC | #2
Hello Claudiu,

On 14/06/2024 10:19:26+0300, Claudiu wrote:
> +static int rtca3_initial_setup(struct rtca3_priv *priv)
> +{
> +	unsigned long osc32k_rate;
> +	u8 pes, tmp, mask;
> +	u32 sleep_us;
> +	int ret;
> +
> +	osc32k_rate = clk_get_rate(priv->clk);
> +	if (!osc32k_rate)
> +		return -EINVAL;
> +
> +	sleep_us = DIV_ROUND_UP_ULL(1000000ULL, osc32k_rate) * 6;
> +
> +	priv->ppb.ten_sec = DIV_ROUND_CLOSEST_ULL(1000000000ULL, (osc32k_rate * 10));
> +	priv->ppb.sixty_sec = DIV_ROUND_CLOSEST_ULL(1000000000ULL, (osc32k_rate * 60));
> +
> +	/*
> +	 * According to HW manual (section 22.4.2. Clock and count mode setting procedure)
> +	 * we need to wait at least 6 cycles of the 32KHz clock after clock was enabled.
> +	 */
> +	usleep_range(sleep_us, sleep_us + 10);
> +
> +	/* Disable alarm and carry interrupts. */
> +	mask = RTCA3_RCR1_AIE | RTCA3_RCR1_CIE;
> +	rtca3_byte_update_bits(priv, RTCA3_RCR1, mask, 0);
> +	ret = readb_poll_timeout(priv->base + RTCA3_RCR1, tmp, !(tmp & mask),
> +				 10, RTCA3_DEFAULT_TIMEOUT_US);
> +	if (ret)
> +		return ret;
> +
> +	/*
> +	 * Stop the RTC and set to 12 hours mode and calendar count mode.
> +	 * RCR2.START initial value is undefined so we need to stop here
> +	 * all the time.
> +	 */

Certainly not, if you stop the RTC on probe, you lose the time
information, this must only be done when the RTC has never been
initialised. The whole goal of the RTC is the keep time across reboots,
its lifecycle is longer than the system.

Also, why do you insist on 12H-mode? The proper thing to do is to support
12H-mode on read but always use 24H-mode when setting the time.

> +	mask = RTCA3_RCR2_START | RTCA3_RCR2_HR24 | RTCA3_RCR2_CNTMD;
> +	writeb(0, priv->base + RTCA3_RCR2);
> +	ret = readb_poll_timeout(priv->base + RTCA3_RCR2, tmp, !(tmp & mask),
> +				 10, RTCA3_DEFAULT_TIMEOUT_US);
> +	if (ret)
> +		return ret;
> +
> +	/* Execute reset and wait for reset and calendar count mode to be applied. */
> +	mask = RTCA3_RCR2_RESET | RTCA3_RCR2_CNTMD;
> +	writeb(RTCA3_RCR2_RESET, priv->base + RTCA3_RCR2);
> +	ret = readb_poll_timeout(priv->base + RTCA3_RCR2, tmp, !(tmp & mask),
> +				 10, RTCA3_RESET_TIMEOUT_US);
> +	if (ret)
> +		return ret;
> +
> +	/*
> +	 * According to HW manual (section 22.6.3. Notes on writing to and reading
> +	 * from registers) after reset we need to wait 6 clock cycles before
> +	 * writing to RTC registers.
> +	 */
> +	usleep_range(sleep_us, sleep_us + 10);
> +
> +	/* Set no adjustment. */
> +	writeb(0, priv->base + RTCA3_RADJ);
> +	ret = readb_poll_timeout(priv->base + RTCA3_RADJ, tmp, !tmp, 10,
> +				 RTCA3_DEFAULT_TIMEOUT_US);
> +
> +	/* Start the RTC and enable automatic time error adjustment. */
> +	mask = RTCA3_RCR2_START | RTCA3_RCR2_AADJE;
> +	writeb(RTCA3_RCR2_START | RTCA3_RCR2_AADJE, priv->base + RTCA3_RCR2);
> +	ret = readb_poll_timeout(priv->base + RTCA3_RCR2, tmp, ((tmp & mask) == mask),
> +				 10, RTCA3_START_TIMEOUT_US);
> +	if (ret)
> +		return ret;
> +
> +	/*
> +	 * According to HW manual (section 22.6.4. Notes on writing to and reading
> +	 * from registers) we need to wait 1/128 seconds while the clock is operating
> +	 * (RCR2.START bit = 1) to be able to read the counters after a return from
> +	 * reset.
> +	 */
> +	usleep_range(8000, 9000);
> +
> +	/* Set period interrupt to 1/64 seconds. It is necessary for alarm setup. */
> +	pes = FIELD_PREP(RTCA3_RCR1_PES, RTCA3_RCR1_PES_1_64_SEC);
> +	rtca3_byte_update_bits(priv, RTCA3_RCR1, RTCA3_RCR1_PES, pes);
> +	return readb_poll_timeout(priv->base + RTCA3_RCR1, tmp, ((tmp & RTCA3_RCR1_PES) == pes),
> +				  10, RTCA3_DEFAULT_TIMEOUT_US);
> +}
> +
> +static int rtca3_request_irqs(struct platform_device *pdev, struct rtca3_priv *priv)
> +{
> +	struct device *dev = &pdev->dev;
> +	int ret, irq;
> +
> +	irq = platform_get_irq_byname(pdev, "alarm");
> +	if (irq < 0)
> +		return dev_err_probe(dev, irq, "Failed to get alarm IRQ!\n");
> +
> +	ret = devm_request_irq(dev, irq, rtca3_alarm_handler, 0, "rtca3-alarm", priv);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "Failed to request alarm IRQ!\n");
> +	priv->wakeup_irq = irq;
> +
> +	irq = platform_get_irq_byname(pdev, "period");
> +	if (irq < 0)
> +		return dev_err_probe(dev, irq, "Failed to get period IRQ!\n");
> +
> +	ret = devm_request_irq(dev, irq, rtca3_periodic_handler, 0, "rtca3-period", priv);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "Failed to request period IRQ!\n");
> +
> +	/*
> +	 * Driver doesn't implement carry handler. Just get the IRQ here
> +	 * for backward compatibility, in case carry support will be added later.
> +	 */
> +	irq = platform_get_irq_byname(pdev, "carry");
> +	if (irq < 0)
> +		return dev_err_probe(dev, irq, "Failed to get carry IRQ!\n");
> +
> +	return 0;
> +}
> +
> +static int rtca3_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct rtca3_priv *priv;
> +	int ret;
> +
> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	priv->base = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(priv->base))
> +		return PTR_ERR(priv->base);
> +
> +	priv->clk = devm_clk_get_enabled(dev, "counter");
> +	if (IS_ERR(priv->clk))
> +		return PTR_ERR(priv->clk);
> +
> +	platform_set_drvdata(pdev, priv);
> +
> +	spin_lock_init(&priv->lock);
> +	atomic_set(&priv->alrm_sstep, RTCA3_ALRM_SSTEP_DONE);
> +	init_completion(&priv->set_alarm_completion);
> +
> +	ret = rtca3_initial_setup(priv);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "Failed to setup the RTC!\n");
> +
> +	ret = rtca3_request_irqs(pdev, priv);
> +	if (ret)
> +		return ret;
> +
> +	device_init_wakeup(&pdev->dev, 1);
> +
> +	priv->rtc_dev = devm_rtc_allocate_device(&pdev->dev);
> +	if (IS_ERR(priv->rtc_dev))
> +		return PTR_ERR(priv->rtc_dev);
> +
> +	priv->rtc_dev->ops = &rtca3_ops;
> +	priv->rtc_dev->max_user_freq = 256;
> +	priv->rtc_dev->range_min = mktime64(1999, 1, 1, 0, 0, 0);
> +	priv->rtc_dev->range_max = mktime64(2098, 12, 31, 23, 59, 59);

This very much looks like the range should be 2000 to 2099, why do you
want to shift it?
claudiu beznea June 14, 2024, 11:06 a.m. UTC | #3
Hi, Alexandre,

On 14.06.2024 12:21, Alexandre Belloni wrote:
> Hello Claudiu,
> 
> On 14/06/2024 10:19:26+0300, Claudiu wrote:
>> +static int rtca3_initial_setup(struct rtca3_priv *priv)
>> +{
>> +	unsigned long osc32k_rate;
>> +	u8 pes, tmp, mask;
>> +	u32 sleep_us;
>> +	int ret;
>> +
>> +	osc32k_rate = clk_get_rate(priv->clk);
>> +	if (!osc32k_rate)
>> +		return -EINVAL;
>> +
>> +	sleep_us = DIV_ROUND_UP_ULL(1000000ULL, osc32k_rate) * 6;
>> +
>> +	priv->ppb.ten_sec = DIV_ROUND_CLOSEST_ULL(1000000000ULL, (osc32k_rate * 10));
>> +	priv->ppb.sixty_sec = DIV_ROUND_CLOSEST_ULL(1000000000ULL, (osc32k_rate * 60));
>> +
>> +	/*
>> +	 * According to HW manual (section 22.4.2. Clock and count mode setting procedure)
>> +	 * we need to wait at least 6 cycles of the 32KHz clock after clock was enabled.
>> +	 */
>> +	usleep_range(sleep_us, sleep_us + 10);
>> +
>> +	/* Disable alarm and carry interrupts. */
>> +	mask = RTCA3_RCR1_AIE | RTCA3_RCR1_CIE;
>> +	rtca3_byte_update_bits(priv, RTCA3_RCR1, mask, 0);
>> +	ret = readb_poll_timeout(priv->base + RTCA3_RCR1, tmp, !(tmp & mask),
>> +				 10, RTCA3_DEFAULT_TIMEOUT_US);
>> +	if (ret)
>> +		return ret;
>> +
>> +	/*
>> +	 * Stop the RTC and set to 12 hours mode and calendar count mode.
>> +	 * RCR2.START initial value is undefined so we need to stop here
>> +	 * all the time.
>> +	 */
> 
> Certainly not, if you stop the RTC on probe, you lose the time
> information, this must only be done when the RTC has never been
> initialised. The whole goal of the RTC is the keep time across reboots,
> its lifecycle is longer than the system.

This was also my first thought when I read the HW manual.

It has been done like this to follow the HW manual. According to HW manual
[1], chapter 22.3.19 RTC Control Register 2 (RCR2), initial value of START
bit is undefined.

If it's 1 while probing but it has never been initialized, we can falsely
detect that RTC is started and skip the rest of the initialization steps.
W/o initialization configuration, the RTC will not be able to work.

Even with this implementation we don't loose the time b/w reboots. Here is
the output on my board [2]. The steps I did were the following:
1/ remove the power to the board (I don't have a battery for RTC installed
   at the moment)
2/ boot the board and issue hwclock -w
3/ reboot
4/ check the systime and rtc time
5/ poweroff
6/ poweron
7/ boot and check systime and RTC time

As you can see the time is not lost but continue to increment. I presume
the hardware takes into account that time needs to increment when initial
configuration is executed.

[1]
https://www.renesas.com/us/en/products/microcontrollers-microprocessors/rz-mpus/rzg3s-general-purpose-microprocessors-single-core-arm-cortex-a55-11-ghz-cpu-and-dual-core-cortex-m33-250
[2] https://p.fr33tux.org/585cd6

> 
> Also, why do you insist on 12H-mode? The proper thing to do is to support
> 12H-mode on read but always use 24H-mode when setting the time.

OK, I wasn't aware of this. I think I followed this approach as it looked
to me the number of operation to update the hardware registers was lower
for 12h mode.

I'll adjust as proposed.

> 
>> +	mask = RTCA3_RCR2_START | RTCA3_RCR2_HR24 | RTCA3_RCR2_CNTMD;
>> +	writeb(0, priv->base + RTCA3_RCR2);
>> +	ret = readb_poll_timeout(priv->base + RTCA3_RCR2, tmp, !(tmp & mask),
>> +				 10, RTCA3_DEFAULT_TIMEOUT_US);
>> +	if (ret)
>> +		return ret;
>> +
>> +	/* Execute reset and wait for reset and calendar count mode to be applied. */
>> +	mask = RTCA3_RCR2_RESET | RTCA3_RCR2_CNTMD;
>> +	writeb(RTCA3_RCR2_RESET, priv->base + RTCA3_RCR2);
>> +	ret = readb_poll_timeout(priv->base + RTCA3_RCR2, tmp, !(tmp & mask),
>> +				 10, RTCA3_RESET_TIMEOUT_US);
>> +	if (ret)
>> +		return ret;
>> +
>> +	/*
>> +	 * According to HW manual (section 22.6.3. Notes on writing to and reading
>> +	 * from registers) after reset we need to wait 6 clock cycles before
>> +	 * writing to RTC registers.
>> +	 */
>> +	usleep_range(sleep_us, sleep_us + 10);
>> +
>> +	/* Set no adjustment. */
>> +	writeb(0, priv->base + RTCA3_RADJ);
>> +	ret = readb_poll_timeout(priv->base + RTCA3_RADJ, tmp, !tmp, 10,
>> +				 RTCA3_DEFAULT_TIMEOUT_US);
>> +
>> +	/* Start the RTC and enable automatic time error adjustment. */
>> +	mask = RTCA3_RCR2_START | RTCA3_RCR2_AADJE;
>> +	writeb(RTCA3_RCR2_START | RTCA3_RCR2_AADJE, priv->base + RTCA3_RCR2);
>> +	ret = readb_poll_timeout(priv->base + RTCA3_RCR2, tmp, ((tmp & mask) == mask),
>> +				 10, RTCA3_START_TIMEOUT_US);
>> +	if (ret)
>> +		return ret;
>> +
>> +	/*
>> +	 * According to HW manual (section 22.6.4. Notes on writing to and reading
>> +	 * from registers) we need to wait 1/128 seconds while the clock is operating
>> +	 * (RCR2.START bit = 1) to be able to read the counters after a return from
>> +	 * reset.
>> +	 */
>> +	usleep_range(8000, 9000);
>> +
>> +	/* Set period interrupt to 1/64 seconds. It is necessary for alarm setup. */
>> +	pes = FIELD_PREP(RTCA3_RCR1_PES, RTCA3_RCR1_PES_1_64_SEC);
>> +	rtca3_byte_update_bits(priv, RTCA3_RCR1, RTCA3_RCR1_PES, pes);
>> +	return readb_poll_timeout(priv->base + RTCA3_RCR1, tmp, ((tmp & RTCA3_RCR1_PES) == pes),
>> +				  10, RTCA3_DEFAULT_TIMEOUT_US);
>> +}
>> +
>> +static int rtca3_request_irqs(struct platform_device *pdev, struct rtca3_priv *priv)
>> +{
>> +	struct device *dev = &pdev->dev;
>> +	int ret, irq;
>> +
>> +	irq = platform_get_irq_byname(pdev, "alarm");
>> +	if (irq < 0)
>> +		return dev_err_probe(dev, irq, "Failed to get alarm IRQ!\n");
>> +
>> +	ret = devm_request_irq(dev, irq, rtca3_alarm_handler, 0, "rtca3-alarm", priv);
>> +	if (ret)
>> +		return dev_err_probe(dev, ret, "Failed to request alarm IRQ!\n");
>> +	priv->wakeup_irq = irq;
>> +
>> +	irq = platform_get_irq_byname(pdev, "period");
>> +	if (irq < 0)
>> +		return dev_err_probe(dev, irq, "Failed to get period IRQ!\n");
>> +
>> +	ret = devm_request_irq(dev, irq, rtca3_periodic_handler, 0, "rtca3-period", priv);
>> +	if (ret)
>> +		return dev_err_probe(dev, ret, "Failed to request period IRQ!\n");
>> +
>> +	/*
>> +	 * Driver doesn't implement carry handler. Just get the IRQ here
>> +	 * for backward compatibility, in case carry support will be added later.
>> +	 */
>> +	irq = platform_get_irq_byname(pdev, "carry");
>> +	if (irq < 0)
>> +		return dev_err_probe(dev, irq, "Failed to get carry IRQ!\n");
>> +
>> +	return 0;
>> +}
>> +
>> +static int rtca3_probe(struct platform_device *pdev)
>> +{
>> +	struct device *dev = &pdev->dev;
>> +	struct rtca3_priv *priv;
>> +	int ret;
>> +
>> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
>> +	if (!priv)
>> +		return -ENOMEM;
>> +
>> +	priv->base = devm_platform_ioremap_resource(pdev, 0);
>> +	if (IS_ERR(priv->base))
>> +		return PTR_ERR(priv->base);
>> +
>> +	priv->clk = devm_clk_get_enabled(dev, "counter");
>> +	if (IS_ERR(priv->clk))
>> +		return PTR_ERR(priv->clk);
>> +
>> +	platform_set_drvdata(pdev, priv);
>> +
>> +	spin_lock_init(&priv->lock);
>> +	atomic_set(&priv->alrm_sstep, RTCA3_ALRM_SSTEP_DONE);
>> +	init_completion(&priv->set_alarm_completion);
>> +
>> +	ret = rtca3_initial_setup(priv);
>> +	if (ret)
>> +		return dev_err_probe(dev, ret, "Failed to setup the RTC!\n");
>> +
>> +	ret = rtca3_request_irqs(pdev, priv);
>> +	if (ret)
>> +		return ret;
>> +
>> +	device_init_wakeup(&pdev->dev, 1);
>> +
>> +	priv->rtc_dev = devm_rtc_allocate_device(&pdev->dev);
>> +	if (IS_ERR(priv->rtc_dev))
>> +		return PTR_ERR(priv->rtc_dev);
>> +
>> +	priv->rtc_dev->ops = &rtca3_ops;
>> +	priv->rtc_dev->max_user_freq = 256;
>> +	priv->rtc_dev->range_min = mktime64(1999, 1, 1, 0, 0, 0);
>> +	priv->rtc_dev->range_max = mktime64(2098, 12, 31, 23, 59, 59);
> 
> This very much looks like the range should be 2000 to 2099, why do you
> want to shift it?

2000-2099 was my first option for this but then I saw one of your old
commits on this topic and, since I'm not very familiar with RTC,
I took it as example. I'll adjust as you proposed.

commit beee05dfbead
Author: Alexandre Belloni <alexandre.belloni@bootlin.com>
Date:   Wed Mar 20 12:30:10 2019 +0100

    rtc: sh: set range

    The SH RTC is a BCD RTC with some version having 4 digits for the year.

    The range for the RTCs with only 2 digits for the year was unfortunately
    shifted to handle 1999 to 2098.

    Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
    Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>


Thank you for your review,
Claudiu Beznea

> 
>
Alexandre Belloni June 17, 2024, 7:25 a.m. UTC | #4
On 14/06/2024 14:06:38+0300, claudiu beznea wrote:
> >> +	/*
> >> +	 * Stop the RTC and set to 12 hours mode and calendar count mode.
> >> +	 * RCR2.START initial value is undefined so we need to stop here
> >> +	 * all the time.
> >> +	 */
> > 
> > Certainly not, if you stop the RTC on probe, you lose the time
> > information, this must only be done when the RTC has never been
> > initialised. The whole goal of the RTC is the keep time across reboots,
> > its lifecycle is longer than the system.
> 
> This was also my first thought when I read the HW manual.
> 
> It has been done like this to follow the HW manual. According to HW manual
> [1], chapter 22.3.19 RTC Control Register 2 (RCR2), initial value of START
> bit is undefined.
> 
> If it's 1 while probing but it has never been initialized, we can falsely
> detect that RTC is started and skip the rest of the initialization steps.
> W/o initialization configuration, the RTC will not be able to work.
> 
> Even with this implementation we don't loose the time b/w reboots. Here is
> the output on my board [2]. The steps I did were the following:
> 1/ remove the power to the board (I don't have a battery for RTC installed
>    at the moment)
> 2/ boot the board and issue hwclock -w
> 3/ reboot
> 4/ check the systime and rtc time
> 5/ poweroff
> 6/ poweron
> 7/ boot and check systime and RTC time
> 
> As you can see the time is not lost but continue to increment. I presume
> the hardware takes into account that time needs to increment when initial
> configuration is executed.

I don't think so, I guess it stops ticking but the registers are not
reset so when ts starts ticking again, you are not too far from the time
that it should report.

> 
> [1]
> https://www.renesas.com/us/en/products/microcontrollers-microprocessors/rz-mpus/rzg3s-general-purpose-microprocessors-single-core-arm-cortex-a55-11-ghz-cpu-and-dual-core-cortex-m33-250
> [2] https://p.fr33tux.org/585cd6
> 
> > 
> > Also, why do you insist on 12H-mode? The proper thing to do is to support
> > 12H-mode on read but always use 24H-mode when setting the time.
> 
> OK, I wasn't aware of this. I think I followed this approach as it looked
> to me the number of operation to update the hardware registers was lower
> for 12h mode.

How come, using 12H-mode implies testing for the AM/PM bit and doing and
addition while 24H-mode would simply be a read?

> >> +	priv->rtc_dev->ops = &rtca3_ops;
> >> +	priv->rtc_dev->max_user_freq = 256;
> >> +	priv->rtc_dev->range_min = mktime64(1999, 1, 1, 0, 0, 0);
> >> +	priv->rtc_dev->range_max = mktime64(2098, 12, 31, 23, 59, 59);
> > 
> > This very much looks like the range should be 2000 to 2099, why do you
> > want to shift it?
> 
> 2000-2099 was my first option for this but then I saw one of your old
> commits on this topic and, since I'm not very familiar with RTC,
> I took it as example. I'll adjust as you proposed.
> 
> commit beee05dfbead
> Author: Alexandre Belloni <alexandre.belloni@bootlin.com>
> Date:   Wed Mar 20 12:30:10 2019 +0100
> 
>     rtc: sh: set range
> 
>     The SH RTC is a BCD RTC with some version having 4 digits for the year.
> 
>     The range for the RTCs with only 2 digits for the year was unfortunately
>     shifted to handle 1999 to 2098.
> 
>     Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
>     Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

This is because the sh driver predated the introduction of the range and
was already shifting it.
claudiu beznea June 17, 2024, 7:31 a.m. UTC | #5
On 17.06.2024 10:25, Alexandre Belloni wrote:
> On 14/06/2024 14:06:38+0300, claudiu beznea wrote:
>>>> +	/*
>>>> +	 * Stop the RTC and set to 12 hours mode and calendar count mode.
>>>> +	 * RCR2.START initial value is undefined so we need to stop here
>>>> +	 * all the time.
>>>> +	 */
>>>
>>> Certainly not, if you stop the RTC on probe, you lose the time
>>> information, this must only be done when the RTC has never been
>>> initialised. The whole goal of the RTC is the keep time across reboots,
>>> its lifecycle is longer than the system.
>>
>> This was also my first thought when I read the HW manual.
>>
>> It has been done like this to follow the HW manual. According to HW manual
>> [1], chapter 22.3.19 RTC Control Register 2 (RCR2), initial value of START
>> bit is undefined.
>>
>> If it's 1 while probing but it has never been initialized, we can falsely
>> detect that RTC is started and skip the rest of the initialization steps.
>> W/o initialization configuration, the RTC will not be able to work.
>>
>> Even with this implementation we don't loose the time b/w reboots. Here is
>> the output on my board [2]. The steps I did were the following:
>> 1/ remove the power to the board (I don't have a battery for RTC installed
>>    at the moment)
>> 2/ boot the board and issue hwclock -w
>> 3/ reboot
>> 4/ check the systime and rtc time
>> 5/ poweroff
>> 6/ poweron
>> 7/ boot and check systime and RTC time
>>
>> As you can see the time is not lost but continue to increment. I presume
>> the hardware takes into account that time needs to increment when initial
>> configuration is executed.
> 
> I don't think so, I guess it stops ticking but the registers are not
> reset so when ts starts ticking again, you are not too far from the time
> that it should report.

I'll double check with hardware team on this and return with an answer.

Thank you for your review,
Claudiu Beznea

> 
>>
>> [1]
>> https://www.renesas.com/us/en/products/microcontrollers-microprocessors/rz-mpus/rzg3s-general-purpose-microprocessors-single-core-arm-cortex-a55-11-ghz-cpu-and-dual-core-cortex-m33-250
>> [2] https://p.fr33tux.org/585cd6
>>
>>>
>>> Also, why do you insist on 12H-mode? The proper thing to do is to support
>>> 12H-mode on read but always use 24H-mode when setting the time.
>>
>> OK, I wasn't aware of this. I think I followed this approach as it looked
>> to me the number of operation to update the hardware registers was lower
>> for 12h mode.
> 
> How come, using 12H-mode implies testing for the AM/PM bit and doing and
> addition while 24H-mode would simply be a read?
> 
>>>> +	priv->rtc_dev->ops = &rtca3_ops;
>>>> +	priv->rtc_dev->max_user_freq = 256;
>>>> +	priv->rtc_dev->range_min = mktime64(1999, 1, 1, 0, 0, 0);
>>>> +	priv->rtc_dev->range_max = mktime64(2098, 12, 31, 23, 59, 59);
>>>
>>> This very much looks like the range should be 2000 to 2099, why do you
>>> want to shift it?
>>
>> 2000-2099 was my first option for this but then I saw one of your old
>> commits on this topic and, since I'm not very familiar with RTC,
>> I took it as example. I'll adjust as you proposed.
>>
>> commit beee05dfbead
>> Author: Alexandre Belloni <alexandre.belloni@bootlin.com>
>> Date:   Wed Mar 20 12:30:10 2019 +0100
>>
>>     rtc: sh: set range
>>
>>     The SH RTC is a BCD RTC with some version having 4 digits for the year.
>>
>>     The range for the RTCs with only 2 digits for the year was unfortunately
>>     shifted to handle 1999 to 2098.
>>
>>     Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
>>     Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
> 
> This is because the sh driver predated the introduction of the range and
> was already shifting it.
> 
>
diff mbox series

Patch

diff --git a/MAINTAINERS b/MAINTAINERS
index 670b8201973b..0b4bf350c416 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -19173,6 +19173,14 @@  S:	Supported
 F:	Documentation/devicetree/bindings/timer/renesas,rz-mtu3.yaml
 F:	drivers/counter/rz-mtu3-cnt.c
 
+RENESAS RZ/G3S RTC DRIVER
+M:	Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
+L:	linux-rtc@vger.kernel.org
+L:	linux-renesas-soc@vger.kernel.org
+S:	Supported
+F:	Documentation/devicetree/bindings/rtc/renesas,rzg3s-rtc.yaml
+F:	drivers/rtc/rtc-renesas-rtca3.c
+
 RENESAS RZ/N1 A5PSW SWITCH DRIVER
 M:	Clément Léger <clement.leger@bootlin.com>
 L:	linux-renesas-soc@vger.kernel.org
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 2a95b05982ad..3b29b35e48e0 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -1978,6 +1978,16 @@  config RTC_DRV_MA35D1
 	   This driver can also be built as a module, if so, the module
 	   will be called "rtc-ma35d1".
 
+config RTC_DRV_RENESAS_RTCA3
+	tristate "Renesas RTCA-3 RTC"
+	depends on ARCH_RENESAS
+	help
+	  If you say yes here you get support for the Renesas RTCA-3 RTC
+	  available on the Renesas RZ/G3S SoC.
+
+	  This driver can also be built as a module, if so, the module
+	  will be called "rtc-rtca3".
+
 comment "HID Sensor RTC drivers"
 
 config RTC_DRV_HID_SENSOR_TIME
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 3004e372f25f..52844f13b247 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -157,6 +157,7 @@  obj-$(CONFIG_RTC_DRV_RX8025)	+= rtc-rx8025.o
 obj-$(CONFIG_RTC_DRV_RX8111)	+= rtc-rx8111.o
 obj-$(CONFIG_RTC_DRV_RX8581)	+= rtc-rx8581.o
 obj-$(CONFIG_RTC_DRV_RZN1)	+= rtc-rzn1.o
+obj-$(CONFIG_RTC_DRV_RENESAS_RTCA3)	+= rtc-renesas-rtca3.o
 obj-$(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-renesas-rtca3.c b/drivers/rtc/rtc-renesas-rtca3.c
new file mode 100644
index 000000000000..e2edf12d0c54
--- /dev/null
+++ b/drivers/rtc/rtc-renesas-rtca3.c
@@ -0,0 +1,891 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * On-Chip RTC Support available on RZ/G3S SoC
+ *
+ * Copyright (C) 2024 Renesas Electronics Corp.
+ */
+#include <linux/bcd.h>
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/iopoll.h>
+#include <linux/interrupt.h>
+#include <linux/jiffies.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+
+/* Counter registers. */
+#define RTCA3_RSECCNT			0x2
+#define RTCA3_RSECCNT_SEC		GENMASK(6, 0)
+#define RTCA3_RMINCNT			0x4
+#define RTCA3_RMINCNT_MIN		GENMASK(6, 0)
+#define RTCA3_RHRCNT			0x6
+#define RTCA3_RHRCNT_HR			GENMASK(5, 0)
+#define RTCA3_RHRCNT_PM			BIT(6)
+#define RTCA3_RWKCNT			0x8
+#define RTCA3_RWKCNT_WK			GENMASK(2, 0)
+#define RTCA3_RDAYCNT			0xa
+#define RTCA3_RDAYCNT_DAY		GENMASK(5, 0)
+#define RTCA3_RMONCNT			0xc
+#define RTCA3_RMONCNT_MONTH		GENMASK(4, 0)
+#define RTCA3_RYRCNT			0xe
+#define RTCA3_RYRCNT_YEAR		GENMASK(7, 0)
+
+/* Alarm registers. */
+#define RTCA3_RSECAR			0x10
+#define RTCA3_RSECAR_SEC		GENMASK(6, 0)
+#define RTCA3_RMINAR			0x12
+#define RTCA3_RMINAR_MIN		GENMASK(6, 0)
+#define RTCA3_RHRAR			0x14
+#define RTCA3_RHRAR_HR			GENMASK(5, 0)
+#define RTCA3_RHRAR_PM			BIT(6)
+#define RTCA3_RWKAR			0x16
+#define RTCA3_RWKAR_DAYW		GENMASK(2, 0)
+#define RTCA3_RDAYAR			0x18
+#define RTCA3_RDAYAR_DATE		GENMASK(5, 0)
+#define RTCA3_RMONAR			0x1a
+#define RTCA3_RMONAR_MON		GENMASK(4, 0)
+#define RTCA3_RYRAR			0x1c
+#define RTCA3_RYRAR_YR			GENMASK(7, 0)
+#define RTCA3_RYRAREN			0x1e
+
+/* Alarm enable bit (for all alarm registers). */
+#define RTCA3_AR_ENB			BIT(7)
+
+/* Control registers. */
+#define RTCA3_RCR1			0x22
+#define RTCA3_RCR1_AIE			BIT(0)
+#define RTCA3_RCR1_CIE			BIT(1)
+#define RTCA3_RCR1_PIE			BIT(2)
+#define RTCA3_RCR1_PES			GENMASK(7, 4)
+#define RTCA3_RCR1_PES_1_64_SEC		0x8
+#define RTCA3_RCR2			0x24
+#define RTCA3_RCR2_START		BIT(0)
+#define RTCA3_RCR2_RESET		BIT(1)
+#define RTCA3_RCR2_AADJE		BIT(4)
+#define RTCA3_RCR2_ADJP			BIT(5)
+#define RTCA3_RCR2_HR24			BIT(6)
+#define RTCA3_RCR2_CNTMD		BIT(7)
+#define RTCA3_RSR			0x20
+#define RTCA3_RSR_AF			BIT(0)
+#define RTCA3_RSR_CF			BIT(1)
+#define RTCA3_RSR_PF			BIT(2)
+#define RTCA3_RADJ			0x2e
+#define RTCA3_RADJ_ADJ			GENMASK(5, 0)
+#define RTCA3_RADJ_ADJ_MAX		0x3f
+#define RTCA3_RADJ_PMADJ		GENMASK(7, 6)
+#define RTCA3_RADJ_PMADJ_NONE		0
+#define RTCA3_RADJ_PMADJ_ADD		1
+#define RTCA3_RADJ_PMADJ_SUB		2
+
+/* Polling operation timeouts. */
+#define RTCA3_DEFAULT_TIMEOUT_US	150
+#define RTCA3_IRQSET_TIMEOUT_US		5000
+#define RTCA3_START_TIMEOUT_US		150000
+#define RTCA3_RESET_TIMEOUT_US		200000
+
+/**
+ * enum rtca3_alrm_set_step - RTCA3 alarm set steps
+ * @RTCA3_ALRM_SSTEP_DONE: alarm setup done step
+ * @RTCA3_ALRM_SSTEP_IRQ: two 1/64 periodic IRQs were generated step
+ * @RTCA3_ALRM_SSTEP_INIT: alarm setup initialization step
+ */
+enum rtca3_alrm_set_step {
+	RTCA3_ALRM_SSTEP_DONE = 0,
+	RTCA3_ALRM_SSTEP_IRQ = 1,
+	RTCA3_ALRM_SSTEP_INIT = 3,
+};
+
+/**
+ * struct rtca3_ppb_per_cycle - PPB per cycle
+ * @ten_sec: PPB per cycle in 10 seconds adjutment mode
+ * @sixty_sec: PPB per cycle in 60 seconds adjustment mode
+ */
+struct rtca3_ppb_per_cycle {
+	int ten_sec;
+	int sixty_sec;
+};
+
+/**
+ * struct rtca3_priv - RTCA3 private data structure
+ * @base: base address
+ * @clk: RTC clock
+ * @rtc_dev: RTC device
+ * @set_alarm_completion: alarm setup completion
+ * @alrm_sstep: alarm setup step (see enum rtca3_alrm_set_step)
+ * @lock: device lock
+ * @ppb: ppb per cycle for each the available adjustment modes
+ * @wakeup_irq: wakeup IRQ
+ */
+struct rtca3_priv {
+	void __iomem *base;
+	struct clk *clk;
+	struct rtc_device *rtc_dev;
+	struct completion set_alarm_completion;
+	atomic_t alrm_sstep;
+	spinlock_t lock;
+	struct rtca3_ppb_per_cycle ppb;
+	int wakeup_irq;
+};
+
+static void rtca3_byte_update_bits(struct rtca3_priv *priv, u8 off, u8 mask, u8 val)
+{
+	u8 tmp;
+
+	tmp = readb(priv->base + off);
+	tmp &= ~(mask);
+	tmp |= (val & mask);
+	writeb(tmp, priv->base + off);
+}
+
+static u8 rtca3_alarm_handler_helper(struct rtca3_priv *priv)
+{
+	u8 val, pending;
+
+	val = readb(priv->base + RTCA3_RSR);
+	pending = val & RTCA3_RSR_AF;
+	writeb(val & ~pending, priv->base + RTCA3_RSR);
+
+	if (pending)
+		rtc_update_irq(priv->rtc_dev, 1, RTC_AF | RTC_IRQF);
+
+	return pending;
+}
+
+static irqreturn_t rtca3_alarm_handler(int irq, void *dev_id)
+{
+	struct rtca3_priv *priv = dev_id;
+	u8 pending;
+
+	spin_lock(&priv->lock);
+	pending = rtca3_alarm_handler_helper(priv);
+	spin_unlock(&priv->lock);
+
+	return IRQ_RETVAL(pending);
+}
+
+static irqreturn_t rtca3_periodic_handler(int irq, void *dev_id)
+{
+	struct rtca3_priv *priv = dev_id;
+	u8 val, pending;
+
+	spin_lock(&priv->lock);
+
+	val = readb(priv->base + RTCA3_RSR);
+	pending = val & RTCA3_RSR_PF;
+
+	if (pending) {
+		writeb(val & ~pending, priv->base + RTCA3_RSR);
+
+		if (atomic_read(&priv->alrm_sstep) > RTCA3_ALRM_SSTEP_IRQ) {
+			/* Alarm setup in progress. */
+			atomic_dec(&priv->alrm_sstep);
+
+			if (atomic_read(&priv->alrm_sstep) == RTCA3_ALRM_SSTEP_IRQ) {
+				/*
+				 * We got 2 * 1/64 periodic interrupts. Disable
+				 * interrupt and let alarm setup continue.
+				 */
+				rtca3_byte_update_bits(priv, RTCA3_RCR1,
+						       RTCA3_RCR1_PIE, 0);
+				readb_poll_timeout_atomic(priv->base + RTCA3_RCR1, val,
+							  !(val & RTCA3_RCR1_PIE),
+							  10, RTCA3_DEFAULT_TIMEOUT_US);
+				complete(&priv->set_alarm_completion);
+			}
+		}
+	}
+
+	spin_unlock(&priv->lock);
+
+	return IRQ_RETVAL(pending);
+}
+
+static void rtca3_prepare_cntalrm_regs_for_read(struct rtca3_priv *priv, bool cnt)
+{
+	/* Offset b/w time and alarm registers. */
+	u8 offset = cnt ? 0 : 0xe;
+
+	/*
+	 * According to HW manual (section 22.6.4. Notes on writing to and
+	 * reading from registers) after writing to count registers, alarm
+	 * registers, year alarm enable register, bits RCR2.AADJE, AADJP,
+	 * and HR24 register, we need to do 3 empty reads before being
+	 * able to fetch the registers content.
+	 */
+	for (u8 i = 0; i < 3; i++) {
+		readb(priv->base + RTCA3_RSECCNT + offset);
+		readb(priv->base + RTCA3_RMINCNT + offset);
+		readb(priv->base + RTCA3_RHRCNT  + offset);
+		readb(priv->base + RTCA3_RWKCNT  + offset);
+		readb(priv->base + RTCA3_RDAYCNT + offset);
+		readw(priv->base + RTCA3_RYRCNT  + offset);
+		if (!cnt)
+			readb(priv->base + RTCA3_RYRAREN);
+	}
+}
+
+static int rtca3_read_time(struct device *dev, struct rtc_time *tm)
+{
+	struct rtca3_priv *priv = dev_get_drvdata(dev);
+	u8 sec, min, hour, wday, mday, month, tmp;
+	unsigned long flags;
+	u8 trials = 0;
+	int ret = 0;
+	u32 year100;
+	u16 year;
+
+	spin_lock_irqsave(&priv->lock, flags);
+
+	tmp = readb(priv->base + RTCA3_RCR2);
+	if (!(tmp & RTCA3_RCR2_START)) {
+		ret = -EINVAL;
+		goto unlock;
+	}
+
+	do {
+		/* Clear carry interrupt. */
+		rtca3_byte_update_bits(priv, RTCA3_RSR, RTCA3_RSR_CF, 0);
+
+		/* Read counters. */
+		sec = readb(priv->base + RTCA3_RSECCNT);
+		min = readb(priv->base + RTCA3_RMINCNT);
+		hour = readb(priv->base + RTCA3_RHRCNT);
+		wday = readb(priv->base + RTCA3_RWKCNT);
+		mday = readb(priv->base + RTCA3_RDAYCNT);
+		month = readb(priv->base + RTCA3_RMONCNT);
+		year = readw(priv->base + RTCA3_RYRCNT);
+
+		tmp = readb(priv->base + RTCA3_RSR);
+
+		/*
+		 * We cannot generate carries due to reading 64Hz counter as
+		 * the driver doesn't implement carry, thus, carries will be
+		 * generated once per seconds. Add a timeout of 5 trials here
+		 * to avoid infinite loop, if any.
+		 */
+	} while ((tmp & RTCA3_RSR_CF) && ++trials < 5);
+
+	if (trials >= 5) {
+		ret = -ETIMEDOUT;
+		goto unlock;
+	}
+
+	tm->tm_sec = bcd2bin(FIELD_GET(RTCA3_RSECCNT_SEC, sec));
+	tm->tm_min = bcd2bin(FIELD_GET(RTCA3_RMINCNT_MIN, min));
+	tm->tm_hour = bcd2bin(FIELD_GET(RTCA3_RHRCNT_HR, hour));
+	if (hour & RTCA3_RHRCNT_PM)
+		tm->tm_hour += 12;
+	tm->tm_wday = bcd2bin(FIELD_GET(RTCA3_RWKCNT_WK, wday));
+	tm->tm_mday = bcd2bin(FIELD_GET(RTCA3_RDAYCNT_DAY, mday));
+	tm->tm_mon = bcd2bin(FIELD_GET(RTCA3_RMONCNT_MONTH, month)) - 1;
+	year = FIELD_GET(RTCA3_RYRCNT_YEAR, year);
+	year100 = bcd2bin((year == 0x99) ? 0x19 : 0x20);
+	tm->tm_year = (year100 * 100 + bcd2bin(year)) - 1900;
+
+unlock:
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	return ret;
+}
+
+static int rtca3_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct rtca3_priv *priv = dev_get_drvdata(dev);
+	unsigned long flags;
+	u8 rcr2, tmp;
+	int ret;
+
+	spin_lock_irqsave(&priv->lock, flags);
+
+	/* Stop the RTC. */
+	rcr2 = readb(priv->base + RTCA3_RCR2);
+	writeb(rcr2 & ~RTCA3_RCR2_START, priv->base + RTCA3_RCR2);
+	ret = readb_poll_timeout_atomic(priv->base + RTCA3_RCR2, tmp,
+					!(tmp & RTCA3_RCR2_START),
+					10, RTCA3_DEFAULT_TIMEOUT_US);
+	if (ret)
+		goto unlock;
+
+	/* Update time. */
+	writeb(bin2bcd(tm->tm_sec), priv->base + RTCA3_RSECCNT);
+	writeb(bin2bcd(tm->tm_min), priv->base + RTCA3_RMINCNT);
+	if (tm->tm_hour > 12)
+		writeb(RTCA3_RHRCNT_PM | bin2bcd(tm->tm_hour - 12), priv->base + RTCA3_RHRCNT);
+	else
+		writeb(bin2bcd(tm->tm_hour), priv->base + RTCA3_RHRCNT);
+	writeb(bin2bcd(tm->tm_wday), priv->base + RTCA3_RWKCNT);
+	writeb(bin2bcd(tm->tm_mday), priv->base + RTCA3_RDAYCNT);
+	writeb(bin2bcd(tm->tm_mon + 1), priv->base + RTCA3_RMONCNT);
+	writew(bin2bcd(tm->tm_year % 100), priv->base + RTCA3_RYRCNT);
+
+	/* Make sure we can read back the counters. */
+	rtca3_prepare_cntalrm_regs_for_read(priv, true);
+
+	/* Start RTC. */
+	writeb(rcr2 | RTCA3_RCR2_START, priv->base + RTCA3_RCR2);
+	ret = readb_poll_timeout_atomic(priv->base + RTCA3_RCR2, tmp,
+					(tmp & RTCA3_RCR2_START),
+					10, RTCA3_DEFAULT_TIMEOUT_US);
+
+unlock:
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	return ret;
+}
+
+static int rtca3_alarm_irq_enable_helper(struct rtca3_priv *priv,
+					 unsigned int enabled)
+{
+	u8 tmp, mask;
+
+	if (enabled) {
+		rtca3_byte_update_bits(priv, RTCA3_RSR, RTCA3_RSR_AF, 0);
+		mask = RTCA3_RCR1_AIE;
+	} else {
+		mask = 0;
+	}
+
+	rtca3_byte_update_bits(priv, RTCA3_RCR1, RTCA3_RCR1_AIE, mask);
+	return readb_poll_timeout_atomic(priv->base + RTCA3_RCR1, tmp,
+					 ((tmp & RTCA3_RCR1_AIE) == mask),
+					 10, RTCA3_IRQSET_TIMEOUT_US);
+}
+
+static int rtca3_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+	struct rtca3_priv *priv = dev_get_drvdata(dev);
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&priv->lock, flags);
+	ret = rtca3_alarm_irq_enable_helper(priv, enabled);
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	return ret;
+}
+
+static int rtca3_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
+{
+	struct rtca3_priv *priv = dev_get_drvdata(dev);
+	u8 sec, min, hour, wday, mday, month;
+	struct rtc_time *tm = &wkalrm->time;
+	unsigned long flags;
+	u32 year100;
+	u16 year;
+
+	spin_lock_irqsave(&priv->lock, flags);
+
+	sec = readb(priv->base + RTCA3_RSECAR);
+	min = readb(priv->base + RTCA3_RMINAR);
+	hour = readb(priv->base + RTCA3_RHRAR);
+	wday = readb(priv->base + RTCA3_RWKAR);
+	mday = readb(priv->base + RTCA3_RDAYAR);
+	month = readb(priv->base + RTCA3_RMONAR);
+	year = readw(priv->base + RTCA3_RYRAR);
+
+	tm->tm_sec = bcd2bin(FIELD_GET(RTCA3_RSECAR_SEC, sec));
+	tm->tm_min = bcd2bin(FIELD_GET(RTCA3_RMINAR_MIN, min));
+	tm->tm_hour = bcd2bin(FIELD_GET(RTCA3_RHRAR_HR, hour));
+	if (hour & RTCA3_RHRAR_PM)
+		tm->tm_hour += 12;
+	tm->tm_wday = bcd2bin(FIELD_GET(RTCA3_RWKAR_DAYW, wday));
+	tm->tm_mday = bcd2bin(FIELD_GET(RTCA3_RDAYAR_DATE, mday));
+	tm->tm_mon = bcd2bin(FIELD_GET(RTCA3_RMONAR_MON, month)) - 1;
+	year = FIELD_GET(RTCA3_RYRAR_YR, year);
+	year100 = bcd2bin((year == 0x99) ? 0x19 : 0x20);
+	tm->tm_year = (year100 * 100 + bcd2bin(year)) - 1900;
+
+	wkalrm->enabled = !!(readb(priv->base + RTCA3_RCR1) & RTCA3_RCR1_AIE);
+
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	return 0;
+}
+
+static int rtca3_set_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
+{
+	struct rtca3_priv *priv = dev_get_drvdata(dev);
+	struct rtc_time *tm = &wkalrm->time;
+	unsigned long flags;
+	u8 rcr1, tmp;
+	int ret;
+
+	spin_lock_irqsave(&priv->lock, flags);
+
+	tmp = readb(priv->base + RTCA3_RCR2);
+	if (!(tmp & RTCA3_RCR2_START)) {
+		ret = -EPERM;
+		goto unlock;
+	}
+
+	/* Disable AIE to prevent false interrupts. */
+	rcr1 = readb(priv->base + RTCA3_RCR1);
+	rcr1 &= ~RTCA3_RCR1_AIE;
+	writeb(rcr1, priv->base + RTCA3_RCR1);
+	ret = readb_poll_timeout_atomic(priv->base + RTCA3_RCR1, tmp,
+					!(tmp & RTCA3_RCR1_AIE),
+					10, RTCA3_DEFAULT_TIMEOUT_US);
+	if (ret)
+		goto unlock;
+
+	/* Set the time and enable the alarm. */
+	writeb(RTCA3_AR_ENB | bin2bcd(tm->tm_sec), priv->base + RTCA3_RSECAR);
+	writeb(RTCA3_AR_ENB | bin2bcd(tm->tm_min), priv->base + RTCA3_RMINAR);
+	if (tm->tm_hour > 12) {
+		writeb(RTCA3_AR_ENB | RTCA3_RHRAR_PM | bin2bcd(tm->tm_hour - 12),
+		       priv->base + RTCA3_RHRAR);
+	} else {
+		writeb(RTCA3_AR_ENB | bin2bcd(tm->tm_hour), priv->base + RTCA3_RHRAR);
+	}
+	writeb(RTCA3_AR_ENB | bin2bcd(tm->tm_wday), priv->base + RTCA3_RWKAR);
+	writeb(RTCA3_AR_ENB | bin2bcd(tm->tm_mday), priv->base + RTCA3_RDAYAR);
+	writeb(RTCA3_AR_ENB | bin2bcd(tm->tm_mon + 1), priv->base + RTCA3_RMONAR);
+
+	writew(bin2bcd(tm->tm_year % 100), priv->base + RTCA3_RYRAR);
+	writeb(RTCA3_AR_ENB, priv->base + RTCA3_RYRAREN);
+
+	/* Make sure we can read back the counters. */
+	rtca3_prepare_cntalrm_regs_for_read(priv, false);
+
+	/* Need to wait for 2 * 1/64 periodic interrupts to be generated. */
+	atomic_set(&priv->alrm_sstep, RTCA3_ALRM_SSTEP_INIT);
+	reinit_completion(&priv->set_alarm_completion);
+
+	/* Enable periodic interrupt. */
+	rcr1 |= RTCA3_RCR1_PIE;
+	writeb(rcr1, priv->base + RTCA3_RCR1);
+	ret = readb_poll_timeout_atomic(priv->base + RTCA3_RCR1, tmp,
+					(tmp & RTCA3_RCR1_PIE),
+					10, RTCA3_IRQSET_TIMEOUT_US);
+
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	if (ret)
+		goto setup_failed;
+
+	/* Wait for the 2 * 1/64 periodic interrupts. */
+	ret = wait_for_completion_interruptible_timeout(&priv->set_alarm_completion,
+							msecs_to_jiffies(500));
+	if (ret <= 0) {
+		ret = -ETIMEDOUT;
+		goto setup_failed;
+	}
+
+	spin_lock_irqsave(&priv->lock, flags);
+
+	ret = rtca3_alarm_irq_enable_helper(priv, wkalrm->enabled);
+	atomic_set(&priv->alrm_sstep, RTCA3_ALRM_SSTEP_DONE);
+
+unlock:
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	return ret;
+
+setup_failed:
+	spin_lock_irqsave(&priv->lock, flags);
+	/*
+	 * Disable PIE to avoid interrupt storm in case HW needed more than
+	 * specified timeout for setup.
+	 */
+	writeb(rcr1 & ~RTCA3_RCR1_PIE, priv->base + RTCA3_RCR1);
+	readb_poll_timeout_atomic(priv->base + RTCA3_RCR1, tmp, !(tmp & ~RTCA3_RCR1_PIE),
+				  10, RTCA3_DEFAULT_TIMEOUT_US);
+	atomic_set(&priv->alrm_sstep, RTCA3_ALRM_SSTEP_DONE);
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	return ret;
+}
+
+static int rtca3_read_offset(struct device *dev, long *offset)
+{
+	struct rtca3_priv *priv = dev_get_drvdata(dev);
+	u8 val, radj, cycles;
+	unsigned long flags;
+	u32 ppb_per_cycle;
+
+	spin_lock_irqsave(&priv->lock, flags);
+	radj = readb(priv->base + RTCA3_RADJ);
+	val = readb(priv->base + RTCA3_RCR2);
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	cycles = FIELD_GET(RTCA3_RADJ_ADJ, radj);
+
+	if (!cycles) {
+		*offset = 0;
+		return 0;
+	}
+
+	if (val & RTCA3_RCR2_ADJP)
+		ppb_per_cycle = priv->ppb.ten_sec;
+	else
+		ppb_per_cycle = priv->ppb.sixty_sec;
+
+	*offset = cycles * ppb_per_cycle;
+	val = FIELD_GET(RTCA3_RADJ_PMADJ, radj);
+	if (val == RTCA3_RADJ_PMADJ_SUB)
+		*offset = -(*offset);
+
+	return 0;
+}
+
+static int rtca3_set_offset(struct device *dev, long offset)
+{
+	struct rtca3_priv *priv = dev_get_drvdata(dev);
+	int cycles, cycles10, cycles60;
+	unsigned long flags;
+	u8 radj, adjp, tmp;
+	int ret;
+
+	/*
+	 * Automatic time error adjustment could be set at intervals of 10
+	 * or 60 seconds.
+	 */
+	cycles10 = DIV_ROUND_CLOSEST(offset, priv->ppb.ten_sec);
+	cycles60 = DIV_ROUND_CLOSEST(offset, priv->ppb.sixty_sec);
+
+	/* We can set b/w 1 and 63 clock cycles. */
+	if (cycles60 >= -RTCA3_RADJ_ADJ_MAX &&
+	    cycles60 <= RTCA3_RADJ_ADJ_MAX) {
+		cycles = cycles60;
+		adjp = 0;
+	} else if (cycles10 >= -RTCA3_RADJ_ADJ_MAX &&
+		   cycles10 <= RTCA3_RADJ_ADJ_MAX) {
+		cycles = cycles10;
+		adjp = RTCA3_RCR2_ADJP;
+	} else {
+		return -ERANGE;
+	}
+
+	radj = FIELD_PREP(RTCA3_RADJ_ADJ, abs(cycles));
+	if (!cycles)
+		radj |= FIELD_PREP(RTCA3_RADJ_PMADJ, RTCA3_RADJ_PMADJ_NONE);
+	else if (cycles > 0)
+		radj |= FIELD_PREP(RTCA3_RADJ_PMADJ, RTCA3_RADJ_PMADJ_ADD);
+	else
+		radj |= FIELD_PREP(RTCA3_RADJ_PMADJ, RTCA3_RADJ_PMADJ_SUB);
+
+	spin_lock_irqsave(&priv->lock, flags);
+
+	tmp = readb(priv->base + RTCA3_RCR2);
+
+	if ((tmp & RTCA3_RCR2_ADJP) != adjp) {
+		/* RADJ.PMADJ need to be set to zero before setting RCR2.ADJP. */
+		writeb(0, priv->base + RTCA3_RADJ);
+		ret = readb_poll_timeout_atomic(priv->base + RTCA3_RADJ, tmp, !tmp,
+						10, RTCA3_DEFAULT_TIMEOUT_US);
+		if (ret)
+			goto unlock;
+
+		rtca3_byte_update_bits(priv, RTCA3_RCR2, RTCA3_RCR2_ADJP, adjp);
+		ret = readb_poll_timeout_atomic(priv->base + RTCA3_RCR2, tmp,
+						((tmp & RTCA3_RCR2_ADJP) == adjp),
+						10, RTCA3_DEFAULT_TIMEOUT_US);
+		if (ret)
+			goto unlock;
+	}
+
+	writeb(radj, priv->base + RTCA3_RADJ);
+	ret = readb_poll_timeout_atomic(priv->base + RTCA3_RADJ, tmp, (tmp == radj),
+					10, RTCA3_DEFAULT_TIMEOUT_US);
+unlock:
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	return ret;
+}
+
+static const struct rtc_class_ops rtca3_ops = {
+	.read_time = rtca3_read_time,
+	.set_time = rtca3_set_time,
+	.read_alarm = rtca3_read_alarm,
+	.set_alarm = rtca3_set_alarm,
+	.alarm_irq_enable = rtca3_alarm_irq_enable,
+	.set_offset = rtca3_set_offset,
+	.read_offset = rtca3_read_offset,
+};
+
+static int rtca3_initial_setup(struct rtca3_priv *priv)
+{
+	unsigned long osc32k_rate;
+	u8 pes, tmp, mask;
+	u32 sleep_us;
+	int ret;
+
+	osc32k_rate = clk_get_rate(priv->clk);
+	if (!osc32k_rate)
+		return -EINVAL;
+
+	sleep_us = DIV_ROUND_UP_ULL(1000000ULL, osc32k_rate) * 6;
+
+	priv->ppb.ten_sec = DIV_ROUND_CLOSEST_ULL(1000000000ULL, (osc32k_rate * 10));
+	priv->ppb.sixty_sec = DIV_ROUND_CLOSEST_ULL(1000000000ULL, (osc32k_rate * 60));
+
+	/*
+	 * According to HW manual (section 22.4.2. Clock and count mode setting procedure)
+	 * we need to wait at least 6 cycles of the 32KHz clock after clock was enabled.
+	 */
+	usleep_range(sleep_us, sleep_us + 10);
+
+	/* Disable alarm and carry interrupts. */
+	mask = RTCA3_RCR1_AIE | RTCA3_RCR1_CIE;
+	rtca3_byte_update_bits(priv, RTCA3_RCR1, mask, 0);
+	ret = readb_poll_timeout(priv->base + RTCA3_RCR1, tmp, !(tmp & mask),
+				 10, RTCA3_DEFAULT_TIMEOUT_US);
+	if (ret)
+		return ret;
+
+	/*
+	 * Stop the RTC and set to 12 hours mode and calendar count mode.
+	 * RCR2.START initial value is undefined so we need to stop here
+	 * all the time.
+	 */
+	mask = RTCA3_RCR2_START | RTCA3_RCR2_HR24 | RTCA3_RCR2_CNTMD;
+	writeb(0, priv->base + RTCA3_RCR2);
+	ret = readb_poll_timeout(priv->base + RTCA3_RCR2, tmp, !(tmp & mask),
+				 10, RTCA3_DEFAULT_TIMEOUT_US);
+	if (ret)
+		return ret;
+
+	/* Execute reset and wait for reset and calendar count mode to be applied. */
+	mask = RTCA3_RCR2_RESET | RTCA3_RCR2_CNTMD;
+	writeb(RTCA3_RCR2_RESET, priv->base + RTCA3_RCR2);
+	ret = readb_poll_timeout(priv->base + RTCA3_RCR2, tmp, !(tmp & mask),
+				 10, RTCA3_RESET_TIMEOUT_US);
+	if (ret)
+		return ret;
+
+	/*
+	 * According to HW manual (section 22.6.3. Notes on writing to and reading
+	 * from registers) after reset we need to wait 6 clock cycles before
+	 * writing to RTC registers.
+	 */
+	usleep_range(sleep_us, sleep_us + 10);
+
+	/* Set no adjustment. */
+	writeb(0, priv->base + RTCA3_RADJ);
+	ret = readb_poll_timeout(priv->base + RTCA3_RADJ, tmp, !tmp, 10,
+				 RTCA3_DEFAULT_TIMEOUT_US);
+
+	/* Start the RTC and enable automatic time error adjustment. */
+	mask = RTCA3_RCR2_START | RTCA3_RCR2_AADJE;
+	writeb(RTCA3_RCR2_START | RTCA3_RCR2_AADJE, priv->base + RTCA3_RCR2);
+	ret = readb_poll_timeout(priv->base + RTCA3_RCR2, tmp, ((tmp & mask) == mask),
+				 10, RTCA3_START_TIMEOUT_US);
+	if (ret)
+		return ret;
+
+	/*
+	 * According to HW manual (section 22.6.4. Notes on writing to and reading
+	 * from registers) we need to wait 1/128 seconds while the clock is operating
+	 * (RCR2.START bit = 1) to be able to read the counters after a return from
+	 * reset.
+	 */
+	usleep_range(8000, 9000);
+
+	/* Set period interrupt to 1/64 seconds. It is necessary for alarm setup. */
+	pes = FIELD_PREP(RTCA3_RCR1_PES, RTCA3_RCR1_PES_1_64_SEC);
+	rtca3_byte_update_bits(priv, RTCA3_RCR1, RTCA3_RCR1_PES, pes);
+	return readb_poll_timeout(priv->base + RTCA3_RCR1, tmp, ((tmp & RTCA3_RCR1_PES) == pes),
+				  10, RTCA3_DEFAULT_TIMEOUT_US);
+}
+
+static int rtca3_request_irqs(struct platform_device *pdev, struct rtca3_priv *priv)
+{
+	struct device *dev = &pdev->dev;
+	int ret, irq;
+
+	irq = platform_get_irq_byname(pdev, "alarm");
+	if (irq < 0)
+		return dev_err_probe(dev, irq, "Failed to get alarm IRQ!\n");
+
+	ret = devm_request_irq(dev, irq, rtca3_alarm_handler, 0, "rtca3-alarm", priv);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to request alarm IRQ!\n");
+	priv->wakeup_irq = irq;
+
+	irq = platform_get_irq_byname(pdev, "period");
+	if (irq < 0)
+		return dev_err_probe(dev, irq, "Failed to get period IRQ!\n");
+
+	ret = devm_request_irq(dev, irq, rtca3_periodic_handler, 0, "rtca3-period", priv);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to request period IRQ!\n");
+
+	/*
+	 * Driver doesn't implement carry handler. Just get the IRQ here
+	 * for backward compatibility, in case carry support will be added later.
+	 */
+	irq = platform_get_irq_byname(pdev, "carry");
+	if (irq < 0)
+		return dev_err_probe(dev, irq, "Failed to get carry IRQ!\n");
+
+	return 0;
+}
+
+static int rtca3_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct rtca3_priv *priv;
+	int ret;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(priv->base))
+		return PTR_ERR(priv->base);
+
+	priv->clk = devm_clk_get_enabled(dev, "counter");
+	if (IS_ERR(priv->clk))
+		return PTR_ERR(priv->clk);
+
+	platform_set_drvdata(pdev, priv);
+
+	spin_lock_init(&priv->lock);
+	atomic_set(&priv->alrm_sstep, RTCA3_ALRM_SSTEP_DONE);
+	init_completion(&priv->set_alarm_completion);
+
+	ret = rtca3_initial_setup(priv);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to setup the RTC!\n");
+
+	ret = rtca3_request_irqs(pdev, priv);
+	if (ret)
+		return ret;
+
+	device_init_wakeup(&pdev->dev, 1);
+
+	priv->rtc_dev = devm_rtc_allocate_device(&pdev->dev);
+	if (IS_ERR(priv->rtc_dev))
+		return PTR_ERR(priv->rtc_dev);
+
+	priv->rtc_dev->ops = &rtca3_ops;
+	priv->rtc_dev->max_user_freq = 256;
+	priv->rtc_dev->range_min = mktime64(1999, 1, 1, 0, 0, 0);
+	priv->rtc_dev->range_max = mktime64(2098, 12, 31, 23, 59, 59);
+
+	return devm_rtc_register_device(priv->rtc_dev);
+}
+
+static void rtca3_remove(struct platform_device *pdev)
+{
+	struct rtca3_priv *priv = platform_get_drvdata(pdev);
+	u8 tmp, mask = RTCA3_RCR1_AIE | RTCA3_RCR1_PIE;
+	unsigned long flags;
+
+	spin_lock_irqsave(&priv->lock, flags);
+
+	/* Disable alarm, periodic interrupt. */
+	rtca3_byte_update_bits(priv, RTCA3_RCR1, mask, 0);
+	readb_poll_timeout_atomic(priv->base + RTCA3_RCR1, tmp, !(tmp & mask),
+				  10, RTCA3_IRQSET_TIMEOUT_US);
+
+	spin_unlock_irqrestore(&priv->lock, flags);
+}
+
+static int __maybe_unused rtca3_suspend(struct device *dev)
+{
+	struct rtca3_priv *priv = dev_get_drvdata(dev);
+
+	if (!device_may_wakeup(dev))
+		return 0;
+
+	/* Alarm setup in progress. */
+	if (atomic_read(&priv->alrm_sstep) != RTCA3_ALRM_SSTEP_DONE)
+		return -EBUSY;
+
+	enable_irq_wake(priv->wakeup_irq);
+
+	return 0;
+}
+
+static int rtca3_clean_alarm(struct rtca3_priv *priv)
+{
+	struct rtc_device *rtc_dev = priv->rtc_dev;
+	time64_t alarm_time, now;
+	struct rtc_wkalrm alarm;
+	unsigned long flags;
+	struct rtc_time tm;
+	u8 pending;
+	int ret;
+
+	ret = rtc_read_alarm(rtc_dev, &alarm);
+	if (ret)
+		return ret;
+
+	if (!alarm.enabled)
+		return 0;
+
+	ret = rtc_read_time(rtc_dev, &tm);
+	if (ret)
+		return ret;
+
+	alarm_time = rtc_tm_to_time64(&alarm.time);
+	now = rtc_tm_to_time64(&tm);
+	if (alarm_time >= now)
+		return 0;
+
+	/*
+	 * Heuristically, it has been determined that when returning from deep
+	 * sleep state the RTCA3_RSR.AF is zero even though the alarm expired.
+	 * Call again the rtc_update_irq() if alarm helper detects this.
+	 */
+
+	spin_lock_irqsave(&priv->lock, flags);
+	pending = rtca3_alarm_handler_helper(priv);
+	if (!pending)
+		rtc_update_irq(priv->rtc_dev, 1, RTC_AF | RTC_IRQF);
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	return 0;
+}
+
+static int __maybe_unused rtca3_resume(struct device *dev)
+{
+	struct rtca3_priv *priv = dev_get_drvdata(dev);
+
+	if (!device_may_wakeup(dev))
+		return 0;
+
+	disable_irq_wake(priv->wakeup_irq);
+
+	/*
+	 * According to the HW manual (section 22.6.4 Notes on writing to
+	 * and reading from registers) we need to wait 1/128 seconds while
+	 * RCR2.START = 1 to be able to read the counters after a return from low
+	 * power consumption state.
+	 */
+	mdelay(8);
+
+	/*
+	 * The alarm cannot wake the system from deep sleep states. In case
+	 * we return from deep sleep states and the alarm expired we need
+	 * to disable it to avoid failures when setting another alarm.
+	 */
+	return rtca3_clean_alarm(priv);
+}
+
+static SIMPLE_DEV_PM_OPS(rtca3_pm_ops, rtca3_suspend, rtca3_resume);
+
+static const struct of_device_id rtca3_of_match[] = {
+	{ .compatible = "renesas,rzg3s-rtc", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, rtca3_of_match);
+
+static struct platform_driver rtca3_platform_driver = {
+	.driver = {
+		.name = "rtc-rtca3",
+		.pm = &rtca3_pm_ops,
+		.of_match_table = rtca3_of_match,
+	},
+	.probe = rtca3_probe,
+	.remove_new = rtca3_remove,
+};
+module_platform_driver(rtca3_platform_driver);
+
+MODULE_DESCRIPTION("Renesas RTCA-3 RTC driver");
+MODULE_AUTHOR("Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>");
+MODULE_LICENSE("GPL");