From: Ciprian Marian Costea <ciprianmarian.costea@xxxxxxxxxxx> Add a RTC driver for NXP S32G2/S32G3 SoCs. The RTC module is used to enable Suspend to RAM (STR) support on NXP S32G2/S32G3 SoC based boards. 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"); + if (IS_ERR(priv->ipg)) { + dev_err(dev, "Failed to get 'ipg' clock\n"); + return PTR_ERR(priv->ipg); + } + + /* Get RTC runtime clock source */ + for (i = 0; i < RTC_CLK_MUX_SIZE; i++) { + priv->runtime_clk = devm_clk_get_enabled(dev, rtc_clk_src[i]); + if (!IS_ERR(priv->runtime_clk)) { + priv->runtime_src_idx = i; + break; + } + } + + if (IS_ERR(priv->runtime_clk)) { + dev_err(dev, "Failed to get runtime rtc clock\n"); + return PTR_ERR(priv->runtime_clk); + } + + /* If present, get RTC suspend clock source */ + for (i = RTC_CLK_MUX_SIZE; i < RTC_CLK_MUX_SIZE * 2; i++) { + priv->suspend_clk = devm_clk_get_enabled(dev, rtc_clk_src[i]); + if (!IS_ERR(priv->suspend_clk)) { + priv->suspend_src_idx = i; + break; + } + } + + return 0; +} + +static int 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 dev_err_probe(dev, PTR_ERR(priv->rtc_base), + "Failed to map registers\n"); + + 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 dev_err_probe(dev, PTR_ERR(priv->rdev), + "Failed to allocate RTC device\n"); + + ret = rtc_clk_src_switch(priv, priv->runtime_src_idx); + if (ret) + return dev_err_probe(dev, ret, + "Failed clk source switch, err: %d\n", ret); + + platform_set_drvdata(pdev, priv); + priv->rdev->ops = &rtc_ops; + + ret = devm_rtc_register_device(priv->rdev); + if (ret) { + dev_err(dev, "Failed to register RTC device\n"); + goto disable_rtc; + } + + priv->dt_irq_id = platform_get_irq(pdev, 0); + if (priv->dt_irq_id < 0) + return dev_err_probe(dev, priv->dt_irq_id, + "Error reading interrupt # from dts\n"); + + ret = devm_request_irq(dev, priv->dt_irq_id, + 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; + } + + return 0; + +disable_rtc: + s32g_rtc_disable(priv); + return ret; +} + +static void rtc_remove(struct platform_device *pdev) +{ + struct rtc_priv *priv = platform_get_drvdata(pdev); + + s32g_rtc_disable(priv); +} + +static void __maybe_unused 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 __maybe_unused rtc_suspend(struct device *dev) +{ + struct rtc_priv *init_priv = dev_get_drvdata(dev); + struct rtc_priv priv; + long long base_sec; + int ret = 0; + u32 rtcval; + u32 sec; + + if (!device_may_wakeup(dev)) + return 0; + + if (init_priv->suspend_src_idx < 0) + return 0; + + if (rtc_get_clk_src(init_priv) + RTC_CLK_MUX_SIZE == + init_priv->suspend_src_idx) + return 0; + + /* Save last known timestamp before we switch clocks and reinit RTC */ + 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)); + + ret = get_time_left(dev, init_priv, &sec); + if (ret) + return ret; + + /* 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); + + ret = rtc_clk_src_switch(&priv, priv.suspend_src_idx); + if (ret) { + dev_err(dev, "Failed clk source switch, err: %d\n", ret); + return ret; + } + + ret = sec_to_rtcval(&priv, sec, &rtcval); + if (ret) { + dev_warn(dev, "Alarm is too far in the future\n"); + return ret; + } + + s32g_rtc_alarm_irq_enable(dev, 0); + enable_api_irq(dev, 1); + iowrite32(rtcval, priv.rtc_base + APIVAL_OFFSET); + iowrite32(0, priv.rtc_base + RTCVAL_OFFSET); + + return ret; +} + +static int __maybe_unused rtc_resume(struct device *dev) +{ + struct rtc_priv *priv = dev_get_drvdata(dev); + int ret; + + if (!device_may_wakeup(dev)) + return 0; + + if (rtc_get_clk_src(priv) == priv->runtime_src_idx) + return 0; + + /* Disable wake-up interrupts */ + enable_api_irq(dev, 0); + + ret = rtc_clk_src_switch(priv, priv->runtime_src_idx); + if (ret) { + dev_err(dev, "Failed clk source switch, err: %d\n", 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 SIMPLE_DEV_PM_OPS(rtc_pm_ops, + rtc_suspend, rtc_resume); + +static struct platform_driver rtc_driver = { + .driver = { + .name = "s32g-rtc", + .pm = &rtc_pm_ops, + .of_match_table = rtc_dt_ids, + }, + .probe = rtc_probe, + .remove = rtc_remove, +}; +module_platform_driver(rtc_driver); + +MODULE_AUTHOR("NXP"); +MODULE_DESCRIPTION("NXP RTC driver for S32G2/S32G3"); +MODULE_LICENSE("GPL"); -- 2.45.2