From: Ciprian Marian Costea <ciprianmarian.costea@xxxxxxxxxxx>
Add a RTC driver for NXP S32G2/S32G3 SoCs.
RTC tracks clock time during system suspend. It can be a wakeup source
for the S32G2/S32G3 SoC based boards.
The RTC module 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 | 554 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 566 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..ad78423783da
--- /dev/null
+++ b/drivers/rtc/rtc-s32g.c
@@ -0,0 +1,554 @@
+// 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_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 RTCCNT_MAX_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] = {
+ "source0",
+ "source1",
+ "source2",
+ "source3"
+};
+
+struct rtc_time_base {
+ s64 sec;
+ u64 cycles;
+ struct rtc_time tm;
+};
+
+struct rtc_priv {
+ struct rtc_device *rdev;
+ void __iomem *rtc_base;
+ struct clk *ipg;
+ struct clk *clk_src;
+ const struct rtc_soc_data *rtc_data;
+ struct rtc_time_base base;
+ u64 rtc_hz;
+ int dt_irq_id;
+ int clk_src_idx;
+};
+
+struct rtc_soc_data {
+ u32 clk_div;
+ u32 quirks;
+};
+
+static const struct rtc_soc_data rtc_s32g2_data = {
+ .clk_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 past the
+ * 32bit register range
+ */
+static int sec_to_rtcval(const struct rtc_priv *priv,
+ unsigned long seconds, u32 *rtcval)
+{
+ u32 delta_cnt;
+
+ if (!seconds || seconds > cycles_to_sec(priv->rtc_hz, RTCCNT_MAX_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;
+ *rtcval = delta_cnt + ioread32(priv->rtc_base + RTCCNT_OFFSET);
+
+ return 0;
+}
+
+static irqreturn_t s32g_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_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 s64 s32g_rtc_get_time_or_alrm(struct rtc_priv *priv,
+ u32 offset)
+{
+ u32 counter;
+
+ counter = ioread32(priv->rtc_base + offset);
+
+ if (counter < priv->base.cycles)
+ return -EINVAL;
+
+ counter -= priv->base.cycles;
+
+ return priv->base.sec + cycles_to_sec(priv->rtc_hz, counter);
+}
+
+static int s32g_rtc_read_time(struct device *dev,
+ struct rtc_time *tm)
+{
+ struct rtc_priv *priv = dev_get_drvdata(dev);
+ s64 sec;
+
+ 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, rtccnt, rtcval;
+ s64 sec;
+
+ 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) {
+ rtccnt = ioread32(priv->rtc_base + RTCCNT_OFFSET);
+ rtcval = ioread32(priv->rtc_base + RTCVAL_OFFSET);
+
+ if (rtccnt < rtcval)
+ alrm->pending = 1;
+ }
+
+ 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;
+
+ 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);
+ ret = sec_to_rtcval(priv, t_alrm - t_crt, &rtcval);
+ if (ret) {
+ dev_warn(dev, "Alarm is set too far in the future\n");
+ return -ERANGE;
+ }
+
+ ret = read_poll_timeout(ioread32, rtcs, !(rtcs & RTCS_INV_RTC),
+ 0, RTC_SYNCH_TIMEOUT, false, priv->rtc_base + RTCS_OFFSET);
+ if (ret)
+ 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);
+
+ 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 int rtc_clk_src_setup(struct rtc_priv *priv)
+{
+ u32 rtcc = 0;
+
+ switch (priv->clk_src_idx) {
+ 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:
+ return -EINVAL;
+ }
+
+ switch (priv->rtc_data->clk_div) {
+ case DIV512_32:
+ rtcc |= RTCC_DIV512EN;
+ rtcc |= RTCC_DIV32EN;
+ break;
+ case DIV512:
+ rtcc |= RTCC_DIV512EN;
+ break;
+ case DIV32:
+ rtcc |= RTCC_DIV32EN;
+ break;
+ case DIV1:
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ rtcc |= RTCC_RTCIE;
+ /*
+ * 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->ipg = devm_clk_get_enabled(dev, "ipg");
+ if (IS_ERR(priv->ipg))
+ return dev_err_probe(dev, PTR_ERR(priv->ipg),
+ "Failed to get 'ipg' clock\n");
+
+ for (i = 0; i < RTC_CLK_MUX_SIZE; i++) {
+ priv->clk_src = devm_clk_get_enabled(dev, rtc_clk_src[i]);
+ if (!IS_ERR(priv->clk_src)) {
+ priv->clk_src_idx = i;
+ break;
+ }
+ }
+
+ if (IS_ERR(priv->clk_src))
+ return dev_err_probe(dev, PTR_ERR(priv->clk_src),
+ "Failed to get rtc module clock source\n");
+
+ return 0;
+}
+
+static int s32g_rtc_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct rtc_priv *priv;
+ int ret = 0;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->rtc_data = of_device_get_match_data(dev);
+ if (!priv->rtc_data)
+ return -ENODEV;
+
+ priv->rtc_base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(priv->rtc_base))
+ return PTR_ERR(priv->rtc_base);
+
+ device_init_wakeup(dev, true);
+
+ ret = rtc_clk_dts_setup(priv, dev);
+ if (ret)
+ return ret;
+
+ priv->rdev = devm_rtc_allocate_device(dev);
+ if (IS_ERR(priv->rdev))
+ return PTR_ERR(priv->rdev);
+
+ ret = rtc_clk_src_setup(priv);
+ if (ret)
+ return ret;
+
+ priv->rtc_hz = clk_get_rate(priv->clk_src);
+ if (!priv->rtc_hz)
+ return dev_err_probe(dev, -EINVAL, "Failed to get RTC frequency\n");
+
+ priv->rtc_hz /= priv->rtc_data->clk_div;
+
+ platform_set_drvdata(pdev, priv);
+ priv->rdev->ops = &rtc_ops;
+
+ priv->dt_irq_id = platform_get_irq(pdev, 0);
+ if (priv->dt_irq_id < 0)
+ return priv->dt_irq_id;
+
+ ret = devm_request_irq(dev, priv->dt_irq_id,
+ s32g_rtc_handler, 0, dev_name(dev), pdev);
+ if (ret) {
+ dev_err(dev, "Request interrupt %d failed, error: %d\n",
+ priv->dt_irq_id, ret);
+ goto disable_rtc;
+ }
+
+ ret = devm_rtc_register_device(priv->rdev);
+ if (ret)
+ goto disable_rtc;
+
+ return 0;
+
+disable_rtc:
+ s32g_rtc_disable(priv);
+ return ret;
+}
+
+static void enable_api_irq(struct device *dev, unsigned int enabled)
+{
+ struct rtc_priv *priv = dev_get_drvdata(dev);
+ u32 api_irq = RTCC_APIEN | RTCC_APIIE;
+ u32 rtcc;
+
+ rtcc = ioread32(priv->rtc_base + RTCC_OFFSET);
+ if (enabled)
+ rtcc |= api_irq;
+ else
+ rtcc &= ~api_irq;
+ iowrite32(rtcc, priv->rtc_base + RTCC_OFFSET);
+}
+
+static int s32g_rtc_suspend(struct device *dev)
+{
+ struct rtc_priv *init_priv = dev_get_drvdata(dev);
+ struct rtc_priv priv;
+ long long base_sec;
+ u32 rtcval, rtccnt;
+ int ret = 0;
+ u32 sec;
+
+ if (!device_may_wakeup(dev))
+ return 0;
+
+ /* Save last known timestamp */
+ ret = s32g_rtc_read_time(dev, &init_priv->base.tm);
+ if (ret)
+ return ret;
+
+ /*
+ * Use a local copy of the RTC control block to
+ * avoid restoring it on resume path.
+ */
+ memcpy(&priv, init_priv, sizeof(priv));
+
+ rtccnt = ioread32(init_priv->rtc_base + RTCCNT_OFFSET);
+ rtcval = ioread32(init_priv->rtc_base + RTCVAL_OFFSET);
+ sec = cycles_to_sec(init_priv->rtc_hz, rtcval - rtccnt);
+
+ /* Adjust for the number of seconds we'll be asleep */
+ base_sec = rtc_tm_to_time64(&init_priv->base.tm);
+ base_sec += sec;
+ rtc_time64_to_tm(base_sec, &init_priv->base.tm);
+
+ /* Reset RTC to prevent overflow.
+ * RTCCNT (RTC Counter) cannot be individually reset
+ * since it is RO (read-only).
+ */
+ s32g_rtc_disable(&priv);
+ s32g_rtc_enable(&priv);
+
+ ret = sec_to_rtcval(&priv, sec, &rtcval);
+ if (ret) {
+ dev_warn(dev, "Alarm is too far in the future\n");
+ return -ERANGE;
+ }
+
+ enable_api_irq(dev, 1);
+ iowrite32(rtcval, priv.rtc_base + APIVAL_OFFSET);
+ iowrite32(0, priv.rtc_base + RTCVAL_OFFSET);
+
+ return ret;
+}
+
+static int s32g_rtc_resume(struct device *dev)
+{
+ struct rtc_priv *priv = dev_get_drvdata(dev);
+ int ret;
+
+ if (!device_may_wakeup(dev))
+ return 0;
+
+ /* Disable wake-up interrupts */
+ enable_api_irq(dev, 0);
+
+ ret = rtc_clk_src_setup(priv);
+ if (ret)
+ return ret;
+
+ /*
+ * Now RTCCNT has just been reset, and is out of sync with priv->base;
+ * reapply the saved time settings.
+ */
+ return s32g_rtc_set_time(dev, &priv->base.tm);
+}
+
+static const struct of_device_id rtc_dt_ids[] = {
+ { .compatible = "nxp,s32g2-rtc", .data = &rtc_s32g2_data},
+ { /* sentinel */ },
+};
+
+static DEFINE_SIMPLE_DEV_PM_OPS(s32g_rtc_pm_ops,
+ s32g_rtc_suspend, s32g_rtc_resume);
+
+static struct platform_driver s32g_rtc_driver = {
+ .driver = {
+ .name = "s32g-rtc",
+ .pm = pm_sleep_ptr(&s32g_rtc_pm_ops),
+ .of_match_table = rtc_dt_ids,
+ },
+ .probe = s32g_rtc_probe,
+};
+module_platform_driver(s32g_rtc_driver);
+
+MODULE_AUTHOR("NXP");
+MODULE_DESCRIPTION("NXP RTC driver for S32G2/S32G3");
+MODULE_LICENSE("GPL");
--
2.45.2
