RTC tracks clock time during system suspend.
RTC from S32G2/S32G3 is not battery-powered and it is not kept alive
during system reset.
Co-developed-by: Bogdan Hamciuc <bogdan.hamciuc@xxxxxxx>
Signed-off-by: Bogdan Hamciuc <bogdan.hamciuc@xxxxxxx>
Co-developed-by: Ghennadi Procopciuc <Ghennadi.Procopciuc@xxxxxxx>
Signed-off-by: Ghennadi Procopciuc <Ghennadi.Procopciuc@xxxxxxx>
Signed-off-by: Ciprian Marian Costea <ciprianmarian.costea@xxxxxxxxxxx>
---
drivers/rtc/Kconfig | 11 +
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-s32g.c | 692 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 704 insertions(+)
create mode 100644 drivers/rtc/rtc-s32g.c
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index e87c3d74565c..18fc3577f6cd 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -2054,4 +2054,15 @@ config RTC_DRV_SSD202D
This driver can also be built as a module, if so, the module
will be called "rtc-ssd20xd".
+config RTC_DRV_S32G
+ tristate "RTC driver for S32G2/S32G3 SoCs"
+ depends on ARCH_S32 || COMPILE_TEST
+ depends on COMMON_CLK
+ help
+ Say yes to enable RTC driver for platforms based on the
+ S32G2/S32G3 SoC family.
+
+ This RTC module can be used as a wakeup source.
+ Please note that it is not battery-powered.
+
endif # RTC_CLASS
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 8ee79cb18322..a63d010a753c 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -158,6 +158,7 @@ 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-$(CONFIG_RTC_DRV_S32G) += rtc-s32g.o
obj-$(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-s32g.c b/drivers/rtc/rtc-s32g.c
new file mode 100644
index 000000000000..c3792b674a18
--- /dev/null
+++ b/drivers/rtc/rtc-s32g.c
@@ -0,0 +1,692 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2024 NXP
+ */
+
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/err.h>
+#include <linux/iopoll.h>
+#include <linux/math64.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+
+#define RTCC_OFFSET 0x4ul
+#define RTCS_OFFSET 0x8ul
+#define RTCCNT_OFFSET 0xCul
+#define APIVAL_OFFSET 0x10ul
+#define RTCVAL_OFFSET 0x14ul
+
+/* RTCC fields */
+#define RTCC_CNTEN BIT(31)
+#define RTCC_RTCIE_SHIFT 30
+#define RTCC_RTCIE BIT(RTCC_RTCIE_SHIFT)
+#define RTCC_ROVREN BIT(28)
+#define RTCC_APIEN BIT(15)
+#define RTCC_APIIE BIT(14)
+#define RTCC_CLKSEL_OFFSET 12
+#define RTCC_CLKSEL_MASK GENMASK(13, 12)
+#define RTCC_CLKSEL(n) (((n) << 12) & RTCC_CLKSEL_MASK)
+#define RTCC_DIV512EN BIT(11)
+#define RTCC_DIV32EN BIT(10)
+
+/* RTCS fields */
+#define RTCS_RTCF BIT(29)
+#define RTCS_INV_RTC BIT(18)
+#define RTCS_APIF BIT(13)
+#define RTCS_ROVRF BIT(10)
+
+#define ROLLOVER_VAL GENMASK(31, 0)
+#define RTC_SYNCH_TIMEOUT (100 * USEC_PER_MSEC)
+
+#define RTC_CLK_MUX_SIZE 4
+
+/*
+ * S32G2 and S32G3 SoCs have RTC clock source 1 reserved and
+ * should not be used.
+ */
+#define RTC_QUIRK_SRC1_RESERVED BIT(2)
+
+enum {
+ RTC_CLK_SRC0,
+ RTC_CLK_SRC1,
+ RTC_CLK_SRC2,
+ RTC_CLK_SRC3
+};
+
+enum {
+ DIV1 = 1,
+ DIV32 = 32,
+ DIV512 = 512,
+ DIV512_32 = 16384
+};
+
+static const char *rtc_clk_src[RTC_CLK_MUX_SIZE * 2] = {
+ "rtc_runtime_s0",
+ "rtc_runtime_s1",
+ "rtc_runtime_s2",
+ "rtc_runtime_s3",
+ "rtc_standby_s0",
+ "rtc_standby_s1",
+ "rtc_standby_s2",
+ "rtc_standby_s3"
+};
+
+struct rtc_time_base {
+ s64 sec;
+ u64 cycles;
+ u64 rollovers;
+ struct rtc_time tm;
+};
+
+struct rtc_priv {
+ struct rtc_device *rdev;
+ void __iomem *rtc_base;
+ struct clk *ipg;
+ struct clk *runtime_clk;
+ struct clk *suspend_clk;
+ const struct rtc_soc_data *rtc_data;
+ struct rtc_time_base base;
+ u64 rtc_hz;
+ u64 rollovers;
+ int dt_irq_id;
+ int runtime_src_idx;
+ int suspend_src_idx;
+};
+
+struct rtc_soc_data {
+ u32 runtime_div;
+ u32 suspend_div;
+ u32 quirks;
+};
+
+static const struct rtc_soc_data rtc_s32g2_data = {
+ .runtime_div = DIV512,
+ .suspend_div = DIV512,
+ .quirks = RTC_QUIRK_SRC1_RESERVED,
+};
+
+static int is_src1_reserved(struct rtc_priv *priv)
+{
+ return priv->rtc_data->quirks & RTC_QUIRK_SRC1_RESERVED;
+}
+
+static u64 cycles_to_sec(u64 hz, u64 cycles)
+{
+ return div_u64(cycles, hz);
+}
+
+/**
+ * Convert a number of seconds to a value suitable for RTCVAL in our clock's
+ * current configuration.
+ * @rtcval: The value to go into RTCVAL[RTCVAL]
+ * Returns: 0 for success, -EINVAL if @seconds push the counter at least
+ * twice the rollover interval
+ */
+static int sec_to_rtcval(const struct rtc_priv *priv,
+ unsigned long seconds, u32 *rtcval)
+{
+ u32 rtccnt, delta_cnt;
+ u32 target_cnt = 0;
+
+ /* For now, support at most one rollover of the counter */
+ if (!seconds || seconds > cycles_to_sec(priv->rtc_hz, ROLLOVER_VAL))
+ return -EINVAL;
+
+ /*
+ * RTCCNT is read-only; we must return a value relative to the
+ * current value of the counter (and hope we don't linger around
+ * too much before we get to enable the interrupt)
+ */
+ delta_cnt = seconds * priv->rtc_hz;
+ rtccnt = ioread32(priv->rtc_base + RTCCNT_OFFSET);
+
+ if (~rtccnt < delta_cnt)
+ target_cnt = (delta_cnt - ~rtccnt);
+ else
+ target_cnt = rtccnt + delta_cnt;
+
+ /*
+ * According to RTCVAL register description,
+ * its minimum value should be 4.
+ */
+ if (unlikely(target_cnt < 4))
+ target_cnt = 4;
+
+ *rtcval = target_cnt;
+
+ return 0;
+}
+
+static irqreturn_t rtc_handler(int irq, void *dev)
+{
+ struct rtc_priv *priv = platform_get_drvdata(dev);
+ u32 status;
+
+ status = ioread32(priv->rtc_base + RTCS_OFFSET);
+ if (status & RTCS_ROVRF) {
+ if (priv->rollovers == ULONG_MAX)
+ priv->rollovers = 0;
+ else
+ priv->rollovers++;
+ }
+
+ if (status & RTCS_RTCF) {
+ iowrite32(0x0, priv->rtc_base + RTCVAL_OFFSET);
+ rtc_update_irq(priv->rdev, 1, RTC_AF);
+ }
+
+ if (status & RTCS_APIF)
+ rtc_update_irq(priv->rdev, 1, RTC_PF);
+
+ iowrite32(status, priv->rtc_base + RTCS_OFFSET);
+
+ return IRQ_HANDLED;
+}
+
+static int get_time_left(struct device *dev, struct rtc_priv *priv,
+ u32 *sec)
+{
+ u32 rtccnt = ioread32(priv->rtc_base + RTCCNT_OFFSET);
+ u32 rtcval = ioread32(priv->rtc_base + RTCVAL_OFFSET);
+
+ if (rtcval < rtccnt) {
+ dev_err(dev, "RTC timer expired before entering suspend\n");
+ return -EIO;
+ }
+
+ *sec = cycles_to_sec(priv->rtc_hz, rtcval - rtccnt);
+
+ return 0;
+}
+
+static s64 s32g_rtc_get_time_or_alrm(struct rtc_priv *priv,
+ u32 offset)
+{
+ u64 cycles, base_cycles;
+ u32 counter;
+ s64 sec;
+
+ counter = ioread32(priv->rtc_base + offset);
+ cycles = priv->rollovers * ROLLOVER_VAL + counter;
+ base_cycles = priv->base.cycles + priv->base.rollovers * ROLLOVER_VAL;
+
+ if (cycles < base_cycles)
+ return -EINVAL;
+
+ cycles -= base_cycles;
+ sec = priv->base.sec + cycles_to_sec(priv->rtc_hz, cycles);
+
+ return sec;
+}
+
+static int s32g_rtc_read_time(struct device *dev,
+ struct rtc_time *tm)
+{
+ struct rtc_priv *priv = dev_get_drvdata(dev);
+ s64 sec;
+
+ if (!tm)
+ return -EINVAL;
+
+ sec = s32g_rtc_get_time_or_alrm(priv, RTCCNT_OFFSET);
+ if (sec < 0)
+ return -EINVAL;
+
+ rtc_time64_to_tm(sec, tm);
+
+ return 0;
+}
+
+static int s32g_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct rtc_priv *priv = dev_get_drvdata(dev);
+ u32 rtcc, sec_left;
+ s64 sec;
+
+ if (!alrm)
+ return -EINVAL;
+
+ sec = s32g_rtc_get_time_or_alrm(priv, RTCVAL_OFFSET);
+ if (sec < 0)
+ return -EINVAL;
+
+ rtc_time64_to_tm(sec, &alrm->time);
+
+ rtcc = ioread32(priv->rtc_base + RTCC_OFFSET);
+ alrm->enabled = sec && (rtcc & RTCC_RTCIE);
+
+ alrm->pending = 0;
+ if (alrm->enabled && !get_time_left(dev, priv, &sec_left))
+ alrm->pending = !!sec_left;
+
+ return 0;
+}
+
+static int s32g_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+ struct rtc_priv *priv = dev_get_drvdata(dev);
+ u32 rtcc;
+
+ if (!priv->dt_irq_id)
+ return -EIO;
+
+ /*
+ * RTCIE cannot be deasserted because it will also disable the
+ * rollover interrupt.
+ */
+ rtcc = ioread32(priv->rtc_base + RTCC_OFFSET);
+ if (enabled)
+ rtcc |= RTCC_RTCIE;
+
+ iowrite32(rtcc, priv->rtc_base + RTCC_OFFSET);
+
+ return 0;
+}
+
+static int s32g_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct rtc_priv *priv = dev_get_drvdata(dev);
+ struct rtc_time time_crt;
+ long long t_crt, t_alrm;
+ u32 rtcval, rtcs;
+ int ret = 0;
+
+ iowrite32(0x0, priv->rtc_base + RTCVAL_OFFSET);
+
+ t_alrm = rtc_tm_to_time64(&alrm->time);
+
+ /*
+ * Assuming the alarm is being set relative to the same time
+ * returned by our s32g_rtc_read_time callback
+ */
+ ret = s32g_rtc_read_time(dev, &time_crt);
+ if (ret)
+ return ret;
+
+ t_crt = rtc_tm_to_time64(&time_crt);
+ if (t_alrm <= t_crt) {
+ dev_warn(dev, "Alarm is set in the past\n");
+ return -EINVAL;
+ }
+
+ ret = sec_to_rtcval(priv, t_alrm - t_crt, &rtcval);
+ if (ret) {
+ /*
+ * Rollover support enables RTC alarm
+ * for a maximum timespan of ~3 months.
+ */
+ dev_warn(dev, "Alarm is set too far in the future\n");
+ return ret;
+ }
+
+ ret = read_poll_timeout(ioread32, rtcs, !(rtcs & RTCS_INV_RTC),
+ 0, RTC_SYNCH_TIMEOUT, false, priv->rtc_base + RTCS_OFFSET);
+ if (ret) {
+ dev_err(dev, "Synchronization failed\n");
+ return ret;
+ }
+
+ iowrite32(rtcval, priv->rtc_base + RTCVAL_OFFSET);
+
+ return 0;
+}
+
+static int s32g_rtc_set_time(struct device *dev,
+ struct rtc_time *time)
+{
+ struct rtc_priv *priv = dev_get_drvdata(dev);
+
+ if (!time)
+ return -EINVAL;
+
+ priv->base.rollovers = priv->rollovers;
+ priv->base.cycles = ioread32(priv->rtc_base + RTCCNT_OFFSET);
+ priv->base.sec = rtc_tm_to_time64(time);
+
+ return 0;
+}
+
+/*
+ * Disable the 32-bit free running counter.
+ * This allows Clock Source and Divisors selection
+ * to be performed without causing synchronization issues.
+ */
+static void s32g_rtc_disable(struct rtc_priv *priv)
+{
+ u32 rtcc = ioread32(priv->rtc_base + RTCC_OFFSET);
+
+ rtcc &= ~RTCC_CNTEN;
+ iowrite32(rtcc, priv->rtc_base + RTCC_OFFSET);
+}
+
+static void s32g_rtc_enable(struct rtc_priv *priv)
+{
+ u32 rtcc = ioread32(priv->rtc_base + RTCC_OFFSET);
+
+ rtcc |= RTCC_CNTEN;
+ iowrite32(rtcc, priv->rtc_base + RTCC_OFFSET);
+}
+
+static void adjust_dividers(struct rtc_priv *priv,
+ u32 div_val, u32 *reg)
+{
+ switch (div_val) {
+ case DIV512_32:
+ *reg |= RTCC_DIV512EN;
+ *reg |= RTCC_DIV32EN;
+ break;
+ case DIV512:
+ *reg |= RTCC_DIV512EN;
+ break;
+ case DIV32:
+ *reg |= RTCC_DIV32EN;
+ break;
+ default:
+ return;
+ }
+
+ priv->rtc_hz /= div_val;
+}
+
+static int rtc_get_clk_src(struct rtc_priv *priv)
+{
+ return (ioread32(priv->rtc_base + RTCC_OFFSET) &
+ RTCC_CLKSEL_MASK) >> RTCC_CLKSEL_OFFSET;
+}
+
+static int rtc_clk_src_switch(struct rtc_priv *priv, u32 src)
+{
+ struct device *dev = priv->rdev->dev.parent;
+ u32 rtcc = 0;
+
+ switch (src % RTC_CLK_MUX_SIZE) {
+ case RTC_CLK_SRC0:
+ rtcc |= RTCC_CLKSEL(RTC_CLK_SRC0);
+ break;
+ case RTC_CLK_SRC1:
+ if (is_src1_reserved(priv))
+ return -EOPNOTSUPP;
+ rtcc |= RTCC_CLKSEL(RTC_CLK_SRC1);
+ break;
+ case RTC_CLK_SRC2:
+ rtcc |= RTCC_CLKSEL(RTC_CLK_SRC2);
+ break;
+ case RTC_CLK_SRC3:
+ rtcc |= RTCC_CLKSEL(RTC_CLK_SRC3);
+ break;
+ default:
+ dev_err(dev, "Invalid clock mux parent: %d\n", src);
+ return -EINVAL;
+ }
+
+ if (src < RTC_CLK_MUX_SIZE) {
+ priv->rtc_hz = clk_get_rate(priv->runtime_clk);
+ if (!priv->rtc_hz) {
+ dev_err(dev, "Failed to get RTC frequency\n");
+ return -EINVAL;
+ }
+ adjust_dividers(priv, priv->rtc_data->runtime_div, &rtcc);
+ } else {
+ priv->rtc_hz = clk_get_rate(priv->suspend_clk);
+ if (!priv->rtc_hz) {
+ dev_err(dev, "Failed to get RTC frequency\n");
+ return -EINVAL;
+ }
+ adjust_dividers(priv, priv->rtc_data->suspend_div, &rtcc);
+ }
+
+ rtcc |= RTCC_RTCIE | RTCC_ROVREN;
+ /*
+ * Make sure the CNTEN is 0 before we configure
+ * the clock source and dividers.
+ */
+ s32g_rtc_disable(priv);
+ iowrite32(rtcc, priv->rtc_base + RTCC_OFFSET);
+ s32g_rtc_enable(priv);
+
+ return 0;
+}
+
+static const struct rtc_class_ops rtc_ops = {
+ .read_time = s32g_rtc_read_time,
+ .set_time = s32g_rtc_set_time,
+ .read_alarm = s32g_rtc_read_alarm,
+ .set_alarm = s32g_rtc_set_alarm,
+ .alarm_irq_enable = s32g_rtc_alarm_irq_enable,
+};
+
+static int rtc_clk_dts_setup(struct rtc_priv *priv,
+ struct device *dev)
+{
+ int i;
+
+ priv->runtime_src_idx = -EINVAL;
+ priv->suspend_src_idx = -EINVAL;
+
+ priv->ipg = devm_clk_get_enabled(dev, "ipg");
