drivers/rtc/rtc-ti-k3.c - third_party/kernel - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Texas Instruments K3 RTC driver
  *
  * Copyright (C) 2021-2022 Texas Instruments Incorporated - https://www.ti.com/
  */

 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/sys_soc.h>
 #include <linux/property.h>
 #include <linux/regmap.h>
 #include <linux/rtc.h>

 /* Registers */
 #define REG_K3RTC_S_CNT_LSW		0x08
 #define REG_K3RTC_S_CNT_MSW		0x0c
 #define REG_K3RTC_COMP			0x10
 #define REG_K3RTC_ON_OFF_S_CNT_LSW	0x20
 #define REG_K3RTC_ON_OFF_S_CNT_MSW	0x24
 #define REG_K3RTC_SCRATCH0		0x30
 #define REG_K3RTC_SCRATCH7		0x4c
 #define REG_K3RTC_GENERAL_CTL		0x50
 #define REG_K3RTC_IRQSTATUS_RAW_SYS	0x54
 #define REG_K3RTC_IRQSTATUS_SYS		0x58
 #define REG_K3RTC_IRQENABLE_SET_SYS	0x5c
 #define REG_K3RTC_IRQENABLE_CLR_SYS	0x60
 #define REG_K3RTC_SYNCPEND		0x68
 #define REG_K3RTC_KICK0			0x70
 #define REG_K3RTC_KICK1			0x74

 /* Freeze when lsw is read and unfreeze when msw is read */
 #define K3RTC_CNT_FMODE_S_CNT_VALUE	(0x2 << 24)

 /* Magic values for lock/unlock */
 #define K3RTC_KICK0_UNLOCK_VALUE	0x83e70b13
 #define K3RTC_KICK1_UNLOCK_VALUE	0x95a4f1e0

 /* Multiplier for ppb conversions */
 #define K3RTC_PPB_MULT			(1000000000LL)
 /* Min and max values supported with 'offset' interface (swapped sign) */
 #define K3RTC_MIN_OFFSET		(-277761)
 #define K3RTC_MAX_OFFSET		(277778)

 static const struct regmap_config ti_k3_rtc_regmap_config = {
 	.name = "peripheral-registers",
 	.reg_bits = 32,
 	.val_bits = 32,
 	.reg_stride = 4,
 	.max_register = REG_K3RTC_KICK1,
 };

 enum ti_k3_rtc_fields {
 	K3RTC_KICK0,
 	K3RTC_KICK1,
 	K3RTC_S_CNT_LSW,
 	K3RTC_S_CNT_MSW,
 	K3RTC_O32K_OSC_DEP_EN,
 	K3RTC_UNLOCK,
 	K3RTC_CNT_FMODE,
 	K3RTC_PEND,
 	K3RTC_RELOAD_FROM_BBD,
 	K3RTC_COMP,

 	K3RTC_ALM_S_CNT_LSW,
 	K3RTC_ALM_S_CNT_MSW,
 	K3RTC_IRQ_STATUS_RAW,
 	K3RTC_IRQ_STATUS,
 	K3RTC_IRQ_ENABLE_SET,
 	K3RTC_IRQ_ENABLE_CLR,

 	K3RTC_IRQ_STATUS_ALT,
 	K3RTC_IRQ_ENABLE_CLR_ALT,

 	K3_RTC_MAX_FIELDS
 };

 static const struct reg_field ti_rtc_reg_fields[] = {
 	[K3RTC_KICK0] = REG_FIELD(REG_K3RTC_KICK0, 0, 31),
 	[K3RTC_KICK1] = REG_FIELD(REG_K3RTC_KICK1, 0, 31),
 	[K3RTC_S_CNT_LSW] = REG_FIELD(REG_K3RTC_S_CNT_LSW, 0, 31),
 	[K3RTC_S_CNT_MSW] = REG_FIELD(REG_K3RTC_S_CNT_MSW, 0, 15),
 	[K3RTC_O32K_OSC_DEP_EN] = REG_FIELD(REG_K3RTC_GENERAL_CTL, 21, 21),
 	[K3RTC_UNLOCK] = REG_FIELD(REG_K3RTC_GENERAL_CTL, 23, 23),
 	[K3RTC_CNT_FMODE] = REG_FIELD(REG_K3RTC_GENERAL_CTL, 24, 25),
 	[K3RTC_PEND] = REG_FIELD(REG_K3RTC_SYNCPEND, 0, 1),
 	[K3RTC_RELOAD_FROM_BBD] = REG_FIELD(REG_K3RTC_SYNCPEND, 31, 31),
 	[K3RTC_COMP] = REG_FIELD(REG_K3RTC_COMP, 0, 31),

 	/* We use on to off as alarm trigger */
 	[K3RTC_ALM_S_CNT_LSW] = REG_FIELD(REG_K3RTC_ON_OFF_S_CNT_LSW, 0, 31),
 	[K3RTC_ALM_S_CNT_MSW] = REG_FIELD(REG_K3RTC_ON_OFF_S_CNT_MSW, 0, 15),
 	[K3RTC_IRQ_STATUS_RAW] = REG_FIELD(REG_K3RTC_IRQSTATUS_RAW_SYS, 0, 0),
 	[K3RTC_IRQ_STATUS] = REG_FIELD(REG_K3RTC_IRQSTATUS_SYS, 0, 0),
 	[K3RTC_IRQ_ENABLE_SET] = REG_FIELD(REG_K3RTC_IRQENABLE_SET_SYS, 0, 0),
 	[K3RTC_IRQ_ENABLE_CLR] = REG_FIELD(REG_K3RTC_IRQENABLE_CLR_SYS, 0, 0),
 	/* Off to on is alternate */
 	[K3RTC_IRQ_STATUS_ALT] = REG_FIELD(REG_K3RTC_IRQSTATUS_SYS, 1, 1),
 	[K3RTC_IRQ_ENABLE_CLR_ALT] = REG_FIELD(REG_K3RTC_IRQENABLE_CLR_SYS, 1, 1),
 };

 /**
  * struct ti_k3_rtc - Private data for ti-k3-rtc
  * @irq:		IRQ
  * @sync_timeout_us:	data sync timeout period in uSec
  * @rate_32k:		32k clock rate in Hz
  * @rtc_dev:		rtc device
  * @regmap:		rtc mmio regmap
  * @r_fields:		rtc register fields
  */
 struct ti_k3_rtc {
 	unsigned int irq;
 	u32 sync_timeout_us;
 	unsigned long rate_32k;
 	struct rtc_device *rtc_dev;
 	struct regmap *regmap;
 	struct regmap_field *r_fields[K3_RTC_MAX_FIELDS];
 };

 static int k3rtc_field_read(struct ti_k3_rtc *priv, enum ti_k3_rtc_fields f)
 {
 	int ret;
 	int val;

 	ret = regmap_field_read(priv->r_fields[f], &val);
 	/*
 	 * We shouldn't be seeing regmap fail on us for mmio reads
 	 * This is possible if clock context fails, but that isn't the case for us
 	 */
 	if (WARN_ON_ONCE(ret))
 		return ret;
 	return val;
 }

 static void k3rtc_field_write(struct ti_k3_rtc *priv, enum ti_k3_rtc_fields f, u32 val)
 {
 	regmap_field_write(priv->r_fields[f], val);
 }

 /**
  * k3rtc_fence  - Ensure a register sync took place between the two domains
  * @priv:      pointer to priv data
  *
  * Return: 0 if the sync took place, else returns -ETIMEDOUT
  */
 static int k3rtc_fence(struct ti_k3_rtc *priv)
 {
 	int ret;

 	ret = regmap_field_read_poll_timeout(priv->r_fields[K3RTC_PEND], ret,
 					     !ret, 2, priv->sync_timeout_us);

 	return ret;
 }

 static inline int k3rtc_check_unlocked(struct ti_k3_rtc *priv)
 {
 	int ret;

 	ret = k3rtc_field_read(priv, K3RTC_UNLOCK);
 	if (ret < 0)
 		return ret;

 	return (ret) ? 0 : 1;
 }

 static int k3rtc_unlock_rtc(struct ti_k3_rtc *priv)
 {
 	int ret;

 	ret = k3rtc_check_unlocked(priv);
 	if (!ret)
 		return ret;

 	k3rtc_field_write(priv, K3RTC_KICK0, K3RTC_KICK0_UNLOCK_VALUE);
 	k3rtc_field_write(priv, K3RTC_KICK1, K3RTC_KICK1_UNLOCK_VALUE);

 	/* Skip fence since we are going to check the unlock bit as fence */
 	ret = regmap_field_read_poll_timeout(priv->r_fields[K3RTC_UNLOCK], ret,
 					     ret, 2, priv->sync_timeout_us);

 	return ret;
 }

 /*
  * This is the list of SoCs affected by TI's i2327 errata causing the RTC
  * state-machine to break if not unlocked fast enough during boot. These
  * SoCs must have the bootloader unlock this device very early in the
  * boot-flow before we (Linux) can use this device.
  */
 static const struct soc_device_attribute has_erratum_i2327[] = {
 	{ .family = "AM62X", .revision = "SR1.0" },
 	{ /* sentinel */ }
 };

 static int k3rtc_configure(struct device *dev)
 {
 	int ret;
 	struct ti_k3_rtc *priv = dev_get_drvdata(dev);

 	/*
 	 * HWBUG: The compare state machine is broken if the RTC module
 	 * is NOT unlocked in under one second of boot - which is pretty long
 	 * time from the perspective of Linux driver (module load, u-boot
 	 * shell all can take much longer than this.
 	 *
 	 * In such occurrence, it is assumed that the RTC module is unusable
 	 */
 	if (soc_device_match(has_erratum_i2327)) {
 		ret = k3rtc_check_unlocked(priv);
 		/* If there is an error OR if we are locked, return error */
 		if (ret) {
 			dev_err(dev,
 				HW_ERR "Erratum i2327 unlock QUIRK! Cannot operate!!\n");
 			return -EFAULT;
 		}
 	} else {
 		/* May need to explicitly unlock first time */
 		ret = k3rtc_unlock_rtc(priv);
 		if (ret) {
 			dev_err(dev, "Failed to unlock(%d)!\n", ret);
 			return ret;
 		}
 	}

 	/* Enable Shadow register sync on 32k clock boundary */
 	k3rtc_field_write(priv, K3RTC_O32K_OSC_DEP_EN, 0x1);

 	/*
 	 * Wait at least clock sync time before proceeding further programming.
 	 * This ensures that the 32k based sync is active.
 	 */
 	usleep_range(priv->sync_timeout_us, priv->sync_timeout_us + 5);

 	/* We need to ensure fence here to make sure sync here */
 	ret = k3rtc_fence(priv);
 	if (ret) {
 		dev_err(dev,
 			"Failed fence osc_dep enable(%d) - is 32k clk working?!\n", ret);
 		return ret;
 	}

 	/*
 	 * FMODE setting: Reading lower seconds will freeze value on higher
 	 * seconds. This also implies that we must *ALWAYS* read lower seconds
 	 * prior to reading higher seconds
 	 */
 	k3rtc_field_write(priv, K3RTC_CNT_FMODE, K3RTC_CNT_FMODE_S_CNT_VALUE);

 	/* Clear any spurious IRQ sources if any */
 	k3rtc_field_write(priv, K3RTC_IRQ_STATUS_ALT, 0x1);
 	k3rtc_field_write(priv, K3RTC_IRQ_STATUS, 0x1);
 	/* Disable all IRQs */
 	k3rtc_field_write(priv, K3RTC_IRQ_ENABLE_CLR_ALT, 0x1);
 	k3rtc_field_write(priv, K3RTC_IRQ_ENABLE_CLR, 0x1);

 	/* And.. Let us Sync the writes in */
 	return k3rtc_fence(priv);
 }

 static int ti_k3_rtc_read_time(struct device *dev, struct rtc_time *tm)
 {
 	struct ti_k3_rtc *priv = dev_get_drvdata(dev);
 	u32 seconds_lo, seconds_hi;

 	seconds_lo = k3rtc_field_read(priv, K3RTC_S_CNT_LSW);
 	seconds_hi = k3rtc_field_read(priv, K3RTC_S_CNT_MSW);

 	rtc_time64_to_tm((((time64_t)seconds_hi) << 32) | (time64_t)seconds_lo, tm);

 	return 0;
 }

 static int ti_k3_rtc_set_time(struct device *dev, struct rtc_time *tm)
 {
 	struct ti_k3_rtc *priv = dev_get_drvdata(dev);
 	time64_t seconds;

 	seconds = rtc_tm_to_time64(tm);

 	/*
 	 * Read operation on LSW will freeze the RTC, so to update
 	 * the time, we cannot use field operations. Just write since the
 	 * reserved bits are ignored.
 	 */
 	regmap_write(priv->regmap, REG_K3RTC_S_CNT_LSW, seconds);
 	regmap_write(priv->regmap, REG_K3RTC_S_CNT_MSW, seconds >> 32);

 	return k3rtc_fence(priv);
 }

 static int ti_k3_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 {
 	struct ti_k3_rtc *priv = dev_get_drvdata(dev);
 	u32 reg;
 	u32 offset = enabled ? K3RTC_IRQ_ENABLE_SET : K3RTC_IRQ_ENABLE_CLR;

 	reg = k3rtc_field_read(priv, K3RTC_IRQ_ENABLE_SET);
 	if ((enabled && reg) || (!enabled && !reg))
 		return 0;

 	k3rtc_field_write(priv, offset, 0x1);

 	/*
 	 * Ensure the write sync is through - NOTE: it should be OK to have
 	 * ISR to fire as we are checking sync (which should be done in a 32k
 	 * cycle or so).
 	 */
 	return k3rtc_fence(priv);
 }

 static int ti_k3_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 {
 	struct ti_k3_rtc *priv = dev_get_drvdata(dev);
 	u32 seconds_lo, seconds_hi;

 	seconds_lo = k3rtc_field_read(priv, K3RTC_ALM_S_CNT_LSW);
 	seconds_hi = k3rtc_field_read(priv, K3RTC_ALM_S_CNT_MSW);

 	rtc_time64_to_tm((((time64_t)seconds_hi) << 32) | (time64_t)seconds_lo, &alarm->time);

 	alarm->enabled = k3rtc_field_read(priv, K3RTC_IRQ_ENABLE_SET);

 	return 0;
 }

 static int ti_k3_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 {
 	struct ti_k3_rtc *priv = dev_get_drvdata(dev);
 	time64_t seconds;
 	int ret;

 	seconds = rtc_tm_to_time64(&alarm->time);

 	k3rtc_field_write(priv, K3RTC_ALM_S_CNT_LSW, seconds);
 	k3rtc_field_write(priv, K3RTC_ALM_S_CNT_MSW, (seconds >> 32));

 	/* Make sure the alarm time is synced in */
 	ret = k3rtc_fence(priv);
 	if (ret) {
 		dev_err(dev, "Failed to fence(%d)! Potential config issue?\n", ret);
 		return ret;
 	}

 	/* Alarm IRQ enable will do a sync */
 	return ti_k3_rtc_alarm_irq_enable(dev, alarm->enabled);
 }

 static int ti_k3_rtc_read_offset(struct device *dev, long *offset)
 {
 	struct ti_k3_rtc *priv = dev_get_drvdata(dev);
 	u32 ticks_per_hr = priv->rate_32k * 3600;
 	int comp;
 	s64 tmp;

 	comp = k3rtc_field_read(priv, K3RTC_COMP);

 	/* Convert from RTC calibration register format to ppb format */
 	tmp = comp * (s64)K3RTC_PPB_MULT;
 	if (tmp < 0)
 		tmp -= ticks_per_hr / 2LL;
 	else
 		tmp += ticks_per_hr / 2LL;
 	tmp = div_s64(tmp, ticks_per_hr);

 	/* Offset value operates in negative way, so swap sign */
 	*offset = (long)-tmp;

 	return 0;
 }

 static int ti_k3_rtc_set_offset(struct device *dev, long offset)
 {
 	struct ti_k3_rtc *priv = dev_get_drvdata(dev);
 	u32 ticks_per_hr = priv->rate_32k * 3600;
 	int comp;
 	s64 tmp;

 	/* Make sure offset value is within supported range */
 	if (offset < K3RTC_MIN_OFFSET || offset > K3RTC_MAX_OFFSET)
 		return -ERANGE;

 	/* Convert from ppb format to RTC calibration register format */
 	tmp = offset * (s64)ticks_per_hr;
 	if (tmp < 0)
 		tmp -= K3RTC_PPB_MULT / 2LL;
 	else
 		tmp += K3RTC_PPB_MULT / 2LL;
 	tmp = div_s64(tmp, K3RTC_PPB_MULT);

 	/* Offset value operates in negative way, so swap sign */
 	comp = (int)-tmp;

 	k3rtc_field_write(priv, K3RTC_COMP, comp);

 	return k3rtc_fence(priv);
 }

 static irqreturn_t ti_k3_rtc_interrupt(s32 irq, void *dev_id)
 {
 	struct device *dev = dev_id;
 	struct ti_k3_rtc *priv = dev_get_drvdata(dev);
 	u32 reg;
 	int ret;

 	/*
 	 * IRQ assertion can be very fast, however, the IRQ Status clear
 	 * de-assert depends on 32k clock edge in the 32k domain
 	 * If we clear the status prior to the first 32k clock edge,
 	 * the status bit is cleared, but the IRQ stays re-asserted.
 	 *
 	 * To prevent this condition, we need to wait for clock sync time.
 	 * We can either do that by polling the 32k observability signal for
 	 * a toggle OR we could just sleep and let the processor do other
 	 * stuff.
 	 */
 	usleep_range(priv->sync_timeout_us, priv->sync_timeout_us + 2);

 	/* Lets make sure that this is a valid interrupt */
 	reg = k3rtc_field_read(priv, K3RTC_IRQ_STATUS);

 	if (!reg) {
 		u32 raw = k3rtc_field_read(priv, K3RTC_IRQ_STATUS_RAW);

 		dev_err(dev,
 			HW_ERR
 			"Erratum i2327/IRQ trig: status: 0x%08x / 0x%08x\n", reg, raw);
 		return IRQ_NONE;
 	}

 	/*
 	 * Write 1 to clear status reg
 	 * We cannot use a field operation here due to a potential race between
 	 * 32k domain and vbus domain.
 	 */
 	regmap_write(priv->regmap, REG_K3RTC_IRQSTATUS_SYS, 0x1);

 	/* Sync the write in */
 	ret = k3rtc_fence(priv);
 	if (ret) {
 		dev_err(dev, "Failed to fence irq status clr(%d)!\n", ret);
 		return IRQ_NONE;
 	}

 	/*
 	 * Force the 32k status to be reloaded back in to ensure status is
 	 * reflected back correctly.
 	 */
 	k3rtc_field_write(priv, K3RTC_RELOAD_FROM_BBD, 0x1);

 	/* Ensure the write sync is through */
 	ret = k3rtc_fence(priv);
 	if (ret) {
 		dev_err(dev, "Failed to fence reload from bbd(%d)!\n", ret);
 		return IRQ_NONE;
 	}

 	/* Now we ensure that the status bit is cleared */
 	ret = regmap_field_read_poll_timeout(priv->r_fields[K3RTC_IRQ_STATUS],
 					     ret, !ret, 2, priv->sync_timeout_us);
 	if (ret) {
 		dev_err(dev, "Time out waiting for status clear\n");
 		return IRQ_NONE;
 	}

 	/* Notify RTC core on event */
 	rtc_update_irq(priv->rtc_dev, 1, RTC_IRQF | RTC_AF);

 	return IRQ_HANDLED;
 }

 static const struct rtc_class_ops ti_k3_rtc_ops = {
 	.read_time = ti_k3_rtc_read_time,
 	.set_time = ti_k3_rtc_set_time,
 	.read_alarm = ti_k3_rtc_read_alarm,
 	.set_alarm = ti_k3_rtc_set_alarm,
 	.read_offset = ti_k3_rtc_read_offset,
 	.set_offset = ti_k3_rtc_set_offset,
 	.alarm_irq_enable = ti_k3_rtc_alarm_irq_enable,
 };

 static int ti_k3_rtc_scratch_read(void *priv_data, unsigned int offset,
 				  void *val, size_t bytes)
 {
 	struct ti_k3_rtc *priv = (struct ti_k3_rtc *)priv_data;

 	return regmap_bulk_read(priv->regmap, REG_K3RTC_SCRATCH0 + offset, val, bytes / 4);
 }

 static int ti_k3_rtc_scratch_write(void *priv_data, unsigned int offset,
 				   void *val, size_t bytes)
 {
 	struct ti_k3_rtc *priv = (struct ti_k3_rtc *)priv_data;
 	int ret;

 	ret = regmap_bulk_write(priv->regmap, REG_K3RTC_SCRATCH0 + offset, val, bytes / 4);
 	if (ret)
 		return ret;

 	return k3rtc_fence(priv);
 }

 static struct nvmem_config ti_k3_rtc_nvmem_config = {
 	.name = "ti_k3_rtc_scratch",
 	.word_size = 4,
 	.stride = 4,
 	.size = REG_K3RTC_SCRATCH7 - REG_K3RTC_SCRATCH0 + 4,
 	.reg_read = ti_k3_rtc_scratch_read,
 	.reg_write = ti_k3_rtc_scratch_write,
 };

 static int k3rtc_get_32kclk(struct device *dev, struct ti_k3_rtc *priv)
 {
 	struct clk *clk;

 	clk = devm_clk_get_enabled(dev, "osc32k");
 	if (IS_ERR(clk))
 		return PTR_ERR(clk);

 	priv->rate_32k = clk_get_rate(clk);

 	/* Make sure we are exact 32k clock. Else, try to compensate delay */
 	if (priv->rate_32k != 32768)
 		dev_warn(dev, "Clock rate %ld is not 32768! Could misbehave!\n",
 			 priv->rate_32k);

 	/*
 	 * Sync timeout should be two 32k clk sync cycles = ~61uS. We double
 	 * it to comprehend intermediate bus segment and cpu frequency
 	 * deltas
 	 */
 	priv->sync_timeout_us = (u32)(DIV_ROUND_UP_ULL(1000000, priv->rate_32k) * 4);

 	return 0;
 }

 static int k3rtc_get_vbusclk(struct device *dev, struct ti_k3_rtc *priv)
 {
 	struct clk *clk;

 	/* Note: VBUS isn't a context clock, it is needed for hardware operation */
 	clk = devm_clk_get_enabled(dev, "vbus");
 	if (IS_ERR(clk))
 		return PTR_ERR(clk);

 	return 0;
 }

 static int ti_k3_rtc_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct ti_k3_rtc *priv;
 	void __iomem *rtc_base;
 	int ret;

 	priv = devm_kzalloc(dev, sizeof(struct ti_k3_rtc), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;

 	rtc_base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(rtc_base))
 		return PTR_ERR(rtc_base);

 	priv->regmap = devm_regmap_init_mmio(dev, rtc_base, &ti_k3_rtc_regmap_config);
 	if (IS_ERR(priv->regmap))
 		return PTR_ERR(priv->regmap);

 	ret = devm_regmap_field_bulk_alloc(dev, priv->regmap, priv->r_fields,
 					   ti_rtc_reg_fields, K3_RTC_MAX_FIELDS);
 	if (ret)
 		return ret;

 	ret = k3rtc_get_32kclk(dev, priv);
 	if (ret)
 		return ret;
 	ret = k3rtc_get_vbusclk(dev, priv);
 	if (ret)
 		return ret;

 	ret = platform_get_irq(pdev, 0);
 	if (ret < 0)
 		return ret;
 	priv->irq = (unsigned int)ret;

 	priv->rtc_dev = devm_rtc_allocate_device(dev);
 	if (IS_ERR(priv->rtc_dev))
 		return PTR_ERR(priv->rtc_dev);

 	priv->rtc_dev->ops = &ti_k3_rtc_ops;
 	priv->rtc_dev->range_max = (1ULL << 48) - 1;	/* 48Bit seconds */
 	ti_k3_rtc_nvmem_config.priv = priv;

 	ret = devm_request_threaded_irq(dev, priv->irq, NULL,
 					ti_k3_rtc_interrupt,
 					IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
 					dev_name(dev), dev);
 	if (ret) {
 		dev_err(dev, "Could not request IRQ: %d\n", ret);
 		return ret;
 	}

 	platform_set_drvdata(pdev, priv);

 	ret = k3rtc_configure(dev);
 	if (ret)
 		return ret;

 	if (device_property_present(dev, "wakeup-source"))
 		device_init_wakeup(dev, true);
 	else
 		device_set_wakeup_capable(dev, true);

 	ret = devm_rtc_register_device(priv->rtc_dev);
 	if (ret)
 		return ret;

 	return devm_rtc_nvmem_register(priv->rtc_dev, &ti_k3_rtc_nvmem_config);
 }

 static const struct of_device_id ti_k3_rtc_of_match_table[] = {
 	{.compatible = "ti,am62-rtc" },
 	{}
 };
 MODULE_DEVICE_TABLE(of, ti_k3_rtc_of_match_table);

 static int __maybe_unused ti_k3_rtc_suspend(struct device *dev)
 {
 	struct ti_k3_rtc *priv = dev_get_drvdata(dev);

 	if (device_may_wakeup(dev))
 		return enable_irq_wake(priv->irq);

 	return 0;
 }

 static int __maybe_unused ti_k3_rtc_resume(struct device *dev)
 {
 	struct ti_k3_rtc *priv = dev_get_drvdata(dev);

 	if (device_may_wakeup(dev))
 		disable_irq_wake(priv->irq);
 	return 0;
 }

 static SIMPLE_DEV_PM_OPS(ti_k3_rtc_pm_ops, ti_k3_rtc_suspend, ti_k3_rtc_resume);

 static struct platform_driver ti_k3_rtc_driver = {
 	.probe = ti_k3_rtc_probe,
 	.driver = {
 		   .name = "rtc-ti-k3",
 		   .of_match_table = ti_k3_rtc_of_match_table,
 		   .pm = &ti_k3_rtc_pm_ops,
 	},
 };
 module_platform_driver(ti_k3_rtc_driver);

 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("TI K3 RTC driver");
 MODULE_AUTHOR("Nishanth Menon");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Texas Instruments K3 RTC driver
	*
	* Copyright (C) 2021-2022 Texas Instruments Incorporated - https://www.ti.com/
	*/

	#include <linux/clk.h>
	#include <linux/delay.h>
	#include <linux/mod_devicetable.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/platform_device.h>
	#include <linux/sys_soc.h>
	#include <linux/property.h>
	#include <linux/regmap.h>
	#include <linux/rtc.h>

	/* Registers */
	#define REG_K3RTC_S_CNT_LSW 0x08
	#define REG_K3RTC_S_CNT_MSW 0x0c
	#define REG_K3RTC_COMP 0x10
	#define REG_K3RTC_ON_OFF_S_CNT_LSW 0x20
	#define REG_K3RTC_ON_OFF_S_CNT_MSW 0x24
	#define REG_K3RTC_SCRATCH0 0x30
	#define REG_K3RTC_SCRATCH7 0x4c
	#define REG_K3RTC_GENERAL_CTL 0x50
	#define REG_K3RTC_IRQSTATUS_RAW_SYS 0x54
	#define REG_K3RTC_IRQSTATUS_SYS 0x58
	#define REG_K3RTC_IRQENABLE_SET_SYS 0x5c
	#define REG_K3RTC_IRQENABLE_CLR_SYS 0x60
	#define REG_K3RTC_SYNCPEND 0x68
	#define REG_K3RTC_KICK0 0x70
	#define REG_K3RTC_KICK1 0x74

	/* Freeze when lsw is read and unfreeze when msw is read */
	#define K3RTC_CNT_FMODE_S_CNT_VALUE (0x2 << 24)

	/* Magic values for lock/unlock */
	#define K3RTC_KICK0_UNLOCK_VALUE 0x83e70b13
	#define K3RTC_KICK1_UNLOCK_VALUE 0x95a4f1e0

	/* Multiplier for ppb conversions */
	#define K3RTC_PPB_MULT (1000000000LL)
	/* Min and max values supported with 'offset' interface (swapped sign) */
	#define K3RTC_MIN_OFFSET (-277761)
	#define K3RTC_MAX_OFFSET (277778)

	static const struct regmap_config ti_k3_rtc_regmap_config = {
	.name = "peripheral-registers",
	.reg_bits = 32,
	.val_bits = 32,
	.reg_stride = 4,
	.max_register = REG_K3RTC_KICK1,
	};

	enum ti_k3_rtc_fields {
	K3RTC_KICK0,
	K3RTC_KICK1,
	K3RTC_S_CNT_LSW,
	K3RTC_S_CNT_MSW,
	K3RTC_O32K_OSC_DEP_EN,
	K3RTC_UNLOCK,
	K3RTC_CNT_FMODE,
	K3RTC_PEND,
	K3RTC_RELOAD_FROM_BBD,
	K3RTC_COMP,

	K3RTC_ALM_S_CNT_LSW,
	K3RTC_ALM_S_CNT_MSW,
	K3RTC_IRQ_STATUS_RAW,
	K3RTC_IRQ_STATUS,
	K3RTC_IRQ_ENABLE_SET,
	K3RTC_IRQ_ENABLE_CLR,

	K3RTC_IRQ_STATUS_ALT,
	K3RTC_IRQ_ENABLE_CLR_ALT,

	K3_RTC_MAX_FIELDS
	};

	static const struct reg_field ti_rtc_reg_fields[] = {
	[K3RTC_KICK0] = REG_FIELD(REG_K3RTC_KICK0, 0, 31),
	[K3RTC_KICK1] = REG_FIELD(REG_K3RTC_KICK1, 0, 31),
	[K3RTC_S_CNT_LSW] = REG_FIELD(REG_K3RTC_S_CNT_LSW, 0, 31),
	[K3RTC_S_CNT_MSW] = REG_FIELD(REG_K3RTC_S_CNT_MSW, 0, 15),
	[K3RTC_O32K_OSC_DEP_EN] = REG_FIELD(REG_K3RTC_GENERAL_CTL, 21, 21),
	[K3RTC_UNLOCK] = REG_FIELD(REG_K3RTC_GENERAL_CTL, 23, 23),
	[K3RTC_CNT_FMODE] = REG_FIELD(REG_K3RTC_GENERAL_CTL, 24, 25),
	[K3RTC_PEND] = REG_FIELD(REG_K3RTC_SYNCPEND, 0, 1),
	[K3RTC_RELOAD_FROM_BBD] = REG_FIELD(REG_K3RTC_SYNCPEND, 31, 31),
	[K3RTC_COMP] = REG_FIELD(REG_K3RTC_COMP, 0, 31),

	/* We use on to off as alarm trigger */
	[K3RTC_ALM_S_CNT_LSW] = REG_FIELD(REG_K3RTC_ON_OFF_S_CNT_LSW, 0, 31),
	[K3RTC_ALM_S_CNT_MSW] = REG_FIELD(REG_K3RTC_ON_OFF_S_CNT_MSW, 0, 15),
	[K3RTC_IRQ_STATUS_RAW] = REG_FIELD(REG_K3RTC_IRQSTATUS_RAW_SYS, 0, 0),
	[K3RTC_IRQ_STATUS] = REG_FIELD(REG_K3RTC_IRQSTATUS_SYS, 0, 0),
	[K3RTC_IRQ_ENABLE_SET] = REG_FIELD(REG_K3RTC_IRQENABLE_SET_SYS, 0, 0),
	[K3RTC_IRQ_ENABLE_CLR] = REG_FIELD(REG_K3RTC_IRQENABLE_CLR_SYS, 0, 0),
	/* Off to on is alternate */
	[K3RTC_IRQ_STATUS_ALT] = REG_FIELD(REG_K3RTC_IRQSTATUS_SYS, 1, 1),
	[K3RTC_IRQ_ENABLE_CLR_ALT] = REG_FIELD(REG_K3RTC_IRQENABLE_CLR_SYS, 1, 1),
	};

	/**
	* struct ti_k3_rtc - Private data for ti-k3-rtc
	* @irq: IRQ
	* @sync_timeout_us: data sync timeout period in uSec
	* @rate_32k: 32k clock rate in Hz
	* @rtc_dev: rtc device
	* @regmap: rtc mmio regmap
	* @r_fields: rtc register fields
	*/
	struct ti_k3_rtc {
	unsigned int irq;
	u32 sync_timeout_us;
	unsigned long rate_32k;
	struct rtc_device *rtc_dev;
	struct regmap *regmap;
	struct regmap_field *r_fields[K3_RTC_MAX_FIELDS];
	};

	static int k3rtc_field_read(struct ti_k3_rtc *priv, enum ti_k3_rtc_fields f)
	{
	int ret;
	int val;

	ret = regmap_field_read(priv->r_fields[f], &val);
	/*
	* We shouldn't be seeing regmap fail on us for mmio reads
	* This is possible if clock context fails, but that isn't the case for us
	*/
	if (WARN_ON_ONCE(ret))
	return ret;
	return val;
	}

	static void k3rtc_field_write(struct ti_k3_rtc *priv, enum ti_k3_rtc_fields f, u32 val)
	{
	regmap_field_write(priv->r_fields[f], val);
	}

	/**
	* k3rtc_fence - Ensure a register sync took place between the two domains
	* @priv: pointer to priv data
	*
	* Return: 0 if the sync took place, else returns -ETIMEDOUT
	*/
	static int k3rtc_fence(struct ti_k3_rtc *priv)
	{
	int ret;

	ret = regmap_field_read_poll_timeout(priv->r_fields[K3RTC_PEND], ret,
	!ret, 2, priv->sync_timeout_us);

	return ret;
	}

	static inline int k3rtc_check_unlocked(struct ti_k3_rtc *priv)
	{
	int ret;

	ret = k3rtc_field_read(priv, K3RTC_UNLOCK);
	if (ret < 0)
	return ret;

	return (ret) ? 0 : 1;
	}

	static int k3rtc_unlock_rtc(struct ti_k3_rtc *priv)
	{
	int ret;

	ret = k3rtc_check_unlocked(priv);
	if (!ret)
	return ret;

	k3rtc_field_write(priv, K3RTC_KICK0, K3RTC_KICK0_UNLOCK_VALUE);
	k3rtc_field_write(priv, K3RTC_KICK1, K3RTC_KICK1_UNLOCK_VALUE);

	/* Skip fence since we are going to check the unlock bit as fence */
	ret = regmap_field_read_poll_timeout(priv->r_fields[K3RTC_UNLOCK], ret,
	ret, 2, priv->sync_timeout_us);

	return ret;
	}

	/*
	* This is the list of SoCs affected by TI's i2327 errata causing the RTC
	* state-machine to break if not unlocked fast enough during boot. These
	* SoCs must have the bootloader unlock this device very early in the
	* boot-flow before we (Linux) can use this device.
	*/
	static const struct soc_device_attribute has_erratum_i2327[] = {
	{ .family = "AM62X", .revision = "SR1.0" },
	{ /* sentinel */ }
	};

	static int k3rtc_configure(struct device *dev)
	{
	int ret;
	struct ti_k3_rtc *priv = dev_get_drvdata(dev);

	/*
	* HWBUG: The compare state machine is broken if the RTC module
	* is NOT unlocked in under one second of boot - which is pretty long
	* time from the perspective of Linux driver (module load, u-boot
	* shell all can take much longer than this.
	*
	* In such occurrence, it is assumed that the RTC module is unusable
	*/
	if (soc_device_match(has_erratum_i2327)) {
	ret = k3rtc_check_unlocked(priv);
	/* If there is an error OR if we are locked, return error */
	if (ret) {
	dev_err(dev,
	HW_ERR "Erratum i2327 unlock QUIRK! Cannot operate!!\n");
	return -EFAULT;
	}
	} else {
	/* May need to explicitly unlock first time */
	ret = k3rtc_unlock_rtc(priv);
	if (ret) {
	dev_err(dev, "Failed to unlock(%d)!\n", ret);
	return ret;
	}
	}

	/* Enable Shadow register sync on 32k clock boundary */
	k3rtc_field_write(priv, K3RTC_O32K_OSC_DEP_EN, 0x1);

	/*
	* Wait at least clock sync time before proceeding further programming.
	* This ensures that the 32k based sync is active.
	*/
	usleep_range(priv->sync_timeout_us, priv->sync_timeout_us + 5);

	/* We need to ensure fence here to make sure sync here */
	ret = k3rtc_fence(priv);
	if (ret) {
	dev_err(dev,
	"Failed fence osc_dep enable(%d) - is 32k clk working?!\n", ret);
	return ret;
	}

	/*
	* FMODE setting: Reading lower seconds will freeze value on higher
	* seconds. This also implies that we must ALWAYS read lower seconds
	* prior to reading higher seconds
	*/
	k3rtc_field_write(priv, K3RTC_CNT_FMODE, K3RTC_CNT_FMODE_S_CNT_VALUE);

	/* Clear any spurious IRQ sources if any */
	k3rtc_field_write(priv, K3RTC_IRQ_STATUS_ALT, 0x1);
	k3rtc_field_write(priv, K3RTC_IRQ_STATUS, 0x1);
	/* Disable all IRQs */
	k3rtc_field_write(priv, K3RTC_IRQ_ENABLE_CLR_ALT, 0x1);
	k3rtc_field_write(priv, K3RTC_IRQ_ENABLE_CLR, 0x1);

	/* And.. Let us Sync the writes in */
	return k3rtc_fence(priv);
	}

	static int ti_k3_rtc_read_time(struct device dev, struct rtc_time tm)
	{
	struct ti_k3_rtc *priv = dev_get_drvdata(dev);
	u32 seconds_lo, seconds_hi;

	seconds_lo = k3rtc_field_read(priv, K3RTC_S_CNT_LSW);
	seconds_hi = k3rtc_field_read(priv, K3RTC_S_CNT_MSW);

	rtc_time64_to_tm((((time64_t)seconds_hi) << 32) \| (time64_t)seconds_lo, tm);

	return 0;
	}

	static int ti_k3_rtc_set_time(struct device dev, struct rtc_time tm)
	{
	struct ti_k3_rtc *priv = dev_get_drvdata(dev);
	time64_t seconds;

	seconds = rtc_tm_to_time64(tm);

	/*
	* Read operation on LSW will freeze the RTC, so to update
	* the time, we cannot use field operations. Just write since the
	* reserved bits are ignored.
	*/
	regmap_write(priv->regmap, REG_K3RTC_S_CNT_LSW, seconds);
	regmap_write(priv->regmap, REG_K3RTC_S_CNT_MSW, seconds >> 32);

	return k3rtc_fence(priv);
	}

	static int ti_k3_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
	{
	struct ti_k3_rtc *priv = dev_get_drvdata(dev);
	u32 reg;
	u32 offset = enabled ? K3RTC_IRQ_ENABLE_SET : K3RTC_IRQ_ENABLE_CLR;

	reg = k3rtc_field_read(priv, K3RTC_IRQ_ENABLE_SET);
	if ((enabled && reg) \|\| (!enabled && !reg))
	return 0;

	k3rtc_field_write(priv, offset, 0x1);

	/*
	* Ensure the write sync is through - NOTE: it should be OK to have
	* ISR to fire as we are checking sync (which should be done in a 32k
	* cycle or so).
	*/
	return k3rtc_fence(priv);
	}

	static int ti_k3_rtc_read_alarm(struct device dev, struct rtc_wkalrm alarm)
	{
	struct ti_k3_rtc *priv = dev_get_drvdata(dev);
	u32 seconds_lo, seconds_hi;

	seconds_lo = k3rtc_field_read(priv, K3RTC_ALM_S_CNT_LSW);
	seconds_hi = k3rtc_field_read(priv, K3RTC_ALM_S_CNT_MSW);

	rtc_time64_to_tm((((time64_t)seconds_hi) << 32) \| (time64_t)seconds_lo, &alarm->time);

	alarm->enabled = k3rtc_field_read(priv, K3RTC_IRQ_ENABLE_SET);

	return 0;
	}

	static int ti_k3_rtc_set_alarm(struct device dev, struct rtc_wkalrm alarm)
	{
	struct ti_k3_rtc *priv = dev_get_drvdata(dev);
	time64_t seconds;
	int ret;

	seconds = rtc_tm_to_time64(&alarm->time);

	k3rtc_field_write(priv, K3RTC_ALM_S_CNT_LSW, seconds);
	k3rtc_field_write(priv, K3RTC_ALM_S_CNT_MSW, (seconds >> 32));

	/* Make sure the alarm time is synced in */
	ret = k3rtc_fence(priv);
	if (ret) {
	dev_err(dev, "Failed to fence(%d)! Potential config issue?\n", ret);
	return ret;
	}

	/* Alarm IRQ enable will do a sync */
	return ti_k3_rtc_alarm_irq_enable(dev, alarm->enabled);
	}

	static int ti_k3_rtc_read_offset(struct device dev, long offset)
	{
	struct ti_k3_rtc *priv = dev_get_drvdata(dev);
	u32 ticks_per_hr = priv->rate_32k * 3600;
	int comp;
	s64 tmp;

	comp = k3rtc_field_read(priv, K3RTC_COMP);

	/* Convert from RTC calibration register format to ppb format */
	tmp = comp * (s64)K3RTC_PPB_MULT;
	if (tmp < 0)
	tmp -= ticks_per_hr / 2LL;
	else
	tmp += ticks_per_hr / 2LL;
	tmp = div_s64(tmp, ticks_per_hr);

	/* Offset value operates in negative way, so swap sign */
	*offset = (long)-tmp;

	return 0;
	}

	static int ti_k3_rtc_set_offset(struct device *dev, long offset)
	{
	struct ti_k3_rtc *priv = dev_get_drvdata(dev);
	u32 ticks_per_hr = priv->rate_32k * 3600;
	int comp;
	s64 tmp;

	/* Make sure offset value is within supported range */
	if (offset < K3RTC_MIN_OFFSET \|\| offset > K3RTC_MAX_OFFSET)
	return -ERANGE;

	/* Convert from ppb format to RTC calibration register format */
	tmp = offset * (s64)ticks_per_hr;
	if (tmp < 0)
	tmp -= K3RTC_PPB_MULT / 2LL;
	else
	tmp += K3RTC_PPB_MULT / 2LL;
	tmp = div_s64(tmp, K3RTC_PPB_MULT);

	/* Offset value operates in negative way, so swap sign */
	comp = (int)-tmp;

	k3rtc_field_write(priv, K3RTC_COMP, comp);

	return k3rtc_fence(priv);
	}

	static irqreturn_t ti_k3_rtc_interrupt(s32 irq, void *dev_id)
	{
	struct device *dev = dev_id;
	struct ti_k3_rtc *priv = dev_get_drvdata(dev);
	u32 reg;
	int ret;

	/*
	* IRQ assertion can be very fast, however, the IRQ Status clear
	* de-assert depends on 32k clock edge in the 32k domain
	* If we clear the status prior to the first 32k clock edge,
	* the status bit is cleared, but the IRQ stays re-asserted.
	*
	* To prevent this condition, we need to wait for clock sync time.
	* We can either do that by polling the 32k observability signal for
	* a toggle OR we could just sleep and let the processor do other
	* stuff.
	*/
	usleep_range(priv->sync_timeout_us, priv->sync_timeout_us + 2);

	/* Lets make sure that this is a valid interrupt */
	reg = k3rtc_field_read(priv, K3RTC_IRQ_STATUS);

	if (!reg) {
	u32 raw = k3rtc_field_read(priv, K3RTC_IRQ_STATUS_RAW);

	dev_err(dev,
	HW_ERR
	"Erratum i2327/IRQ trig: status: 0x%08x / 0x%08x\n", reg, raw);
	return IRQ_NONE;
	}

	/*
	* Write 1 to clear status reg
	* We cannot use a field operation here due to a potential race between
	* 32k domain and vbus domain.
	*/
	regmap_write(priv->regmap, REG_K3RTC_IRQSTATUS_SYS, 0x1);

	/* Sync the write in */
	ret = k3rtc_fence(priv);
	if (ret) {
	dev_err(dev, "Failed to fence irq status clr(%d)!\n", ret);
	return IRQ_NONE;
	}

	/*
	* Force the 32k status to be reloaded back in to ensure status is
	* reflected back correctly.
	*/
	k3rtc_field_write(priv, K3RTC_RELOAD_FROM_BBD, 0x1);

	/* Ensure the write sync is through */
	ret = k3rtc_fence(priv);
	if (ret) {
	dev_err(dev, "Failed to fence reload from bbd(%d)!\n", ret);
	return IRQ_NONE;
	}

	/* Now we ensure that the status bit is cleared */
	ret = regmap_field_read_poll_timeout(priv->r_fields[K3RTC_IRQ_STATUS],
	ret, !ret, 2, priv->sync_timeout_us);
	if (ret) {
	dev_err(dev, "Time out waiting for status clear\n");
	return IRQ_NONE;
	}

	/* Notify RTC core on event */
	rtc_update_irq(priv->rtc_dev, 1, RTC_IRQF \| RTC_AF);

	return IRQ_HANDLED;
	}

	static const struct rtc_class_ops ti_k3_rtc_ops = {
	.read_time = ti_k3_rtc_read_time,
	.set_time = ti_k3_rtc_set_time,
	.read_alarm = ti_k3_rtc_read_alarm,
	.set_alarm = ti_k3_rtc_set_alarm,
	.read_offset = ti_k3_rtc_read_offset,
	.set_offset = ti_k3_rtc_set_offset,
	.alarm_irq_enable = ti_k3_rtc_alarm_irq_enable,
	};

	static int ti_k3_rtc_scratch_read(void *priv_data, unsigned int offset,
	void *val, size_t bytes)
	{
	struct ti_k3_rtc priv = (struct ti_k3_rtc )priv_data;

	return regmap_bulk_read(priv->regmap, REG_K3RTC_SCRATCH0 + offset, val, bytes / 4);
	}

	static int ti_k3_rtc_scratch_write(void *priv_data, unsigned int offset,
	void *val, size_t bytes)
	{
	struct ti_k3_rtc priv = (struct ti_k3_rtc )priv_data;
	int ret;

	ret = regmap_bulk_write(priv->regmap, REG_K3RTC_SCRATCH0 + offset, val, bytes / 4);
	if (ret)
	return ret;

	return k3rtc_fence(priv);
	}

	static struct nvmem_config ti_k3_rtc_nvmem_config = {
	.name = "ti_k3_rtc_scratch",
	.word_size = 4,
	.stride = 4,
	.size = REG_K3RTC_SCRATCH7 - REG_K3RTC_SCRATCH0 + 4,
	.reg_read = ti_k3_rtc_scratch_read,
	.reg_write = ti_k3_rtc_scratch_write,
	};

	static int k3rtc_get_32kclk(struct device dev, struct ti_k3_rtc priv)
	{
	struct clk *clk;

	clk = devm_clk_get_enabled(dev, "osc32k");
	if (IS_ERR(clk))
	return PTR_ERR(clk);

	priv->rate_32k = clk_get_rate(clk);

	/* Make sure we are exact 32k clock. Else, try to compensate delay */
	if (priv->rate_32k != 32768)
	dev_warn(dev, "Clock rate %ld is not 32768! Could misbehave!\n",
	priv->rate_32k);

	/*
	* Sync timeout should be two 32k clk sync cycles = ~61uS. We double
	* it to comprehend intermediate bus segment and cpu frequency
	* deltas
	*/
	priv->sync_timeout_us = (u32)(DIV_ROUND_UP_ULL(1000000, priv->rate_32k) * 4);

	return 0;
	}

	static int k3rtc_get_vbusclk(struct device dev, struct ti_k3_rtc priv)
	{
	struct clk *clk;

	/* Note: VBUS isn't a context clock, it is needed for hardware operation */
	clk = devm_clk_get_enabled(dev, "vbus");
	if (IS_ERR(clk))
	return PTR_ERR(clk);

	return 0;
	}

	static int ti_k3_rtc_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	struct ti_k3_rtc *priv;
	void __iomem *rtc_base;
	int ret;

	priv = devm_kzalloc(dev, sizeof(struct ti_k3_rtc), GFP_KERNEL);
	if (!priv)
	return -ENOMEM;

	rtc_base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(rtc_base))
	return PTR_ERR(rtc_base);

	priv->regmap = devm_regmap_init_mmio(dev, rtc_base, &ti_k3_rtc_regmap_config);
	if (IS_ERR(priv->regmap))
	return PTR_ERR(priv->regmap);

	ret = devm_regmap_field_bulk_alloc(dev, priv->regmap, priv->r_fields,
	ti_rtc_reg_fields, K3_RTC_MAX_FIELDS);
	if (ret)
	return ret;

	ret = k3rtc_get_32kclk(dev, priv);
	if (ret)
	return ret;
	ret = k3rtc_get_vbusclk(dev, priv);
	if (ret)
	return ret;

	ret = platform_get_irq(pdev, 0);
	if (ret < 0)
	return ret;
	priv->irq = (unsigned int)ret;

	priv->rtc_dev = devm_rtc_allocate_device(dev);
	if (IS_ERR(priv->rtc_dev))
	return PTR_ERR(priv->rtc_dev);

	priv->rtc_dev->ops = &ti_k3_rtc_ops;
	priv->rtc_dev->range_max = (1ULL << 48) - 1; /* 48Bit seconds */
	ti_k3_rtc_nvmem_config.priv = priv;

	ret = devm_request_threaded_irq(dev, priv->irq, NULL,
	ti_k3_rtc_interrupt,
	IRQF_TRIGGER_HIGH \| IRQF_ONESHOT,
	dev_name(dev), dev);
	if (ret) {
	dev_err(dev, "Could not request IRQ: %d\n", ret);
	return ret;
	}

	platform_set_drvdata(pdev, priv);

	ret = k3rtc_configure(dev);
	if (ret)
	return ret;

	if (device_property_present(dev, "wakeup-source"))
	device_init_wakeup(dev, true);
	else
	device_set_wakeup_capable(dev, true);

	ret = devm_rtc_register_device(priv->rtc_dev);
	if (ret)
	return ret;

	return devm_rtc_nvmem_register(priv->rtc_dev, &ti_k3_rtc_nvmem_config);
	}

	static const struct of_device_id ti_k3_rtc_of_match_table[] = {
	{.compatible = "ti,am62-rtc" },
	{}
	};
	MODULE_DEVICE_TABLE(of, ti_k3_rtc_of_match_table);

	static int __maybe_unused ti_k3_rtc_suspend(struct device *dev)
	{
	struct ti_k3_rtc *priv = dev_get_drvdata(dev);

	if (device_may_wakeup(dev))
	return enable_irq_wake(priv->irq);

	return 0;
	}

	static int __maybe_unused ti_k3_rtc_resume(struct device *dev)
	{
	struct ti_k3_rtc *priv = dev_get_drvdata(dev);

	if (device_may_wakeup(dev))
	disable_irq_wake(priv->irq);
	return 0;
	}

	static SIMPLE_DEV_PM_OPS(ti_k3_rtc_pm_ops, ti_k3_rtc_suspend, ti_k3_rtc_resume);

	static struct platform_driver ti_k3_rtc_driver = {
	.probe = ti_k3_rtc_probe,
	.driver = {
	.name = "rtc-ti-k3",
	.of_match_table = ti_k3_rtc_of_match_table,
	.pm = &ti_k3_rtc_pm_ops,
	},
	};
	module_platform_driver(ti_k3_rtc_driver);

	MODULE_LICENSE("GPL");
	MODULE_DESCRIPTION("TI K3 RTC driver");
	MODULE_AUTHOR("Nishanth Menon");