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

Claudiu
2024-06-14T07:20:01Z

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
+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");
--
2.39.2