// SPDX-License-Identifier: GPL-2.0+//// Copyright (C) 2011-2012 Freescale Semiconductor, Inc. #include <linux/init.h>#include <linux/io.h>#include <linux/kernel.h>#include <linux/module.h>#include <linux/of.h>#include <linux/platform_device.h>#include <linux/pm_wakeirq.h>#include <linux/rtc.h>#include <linux/clk.h>#include <linux/mfd/syscon.h>#include <linux/regmap.h> #define SNVS_LPREGISTER_OFFSET	0x34 /* These register offsets are relative to LP (Low Power) range */#define SNVS_LPCR		0x04#define SNVS_LPSR		0x18#define SNVS_LPSRTCMR		0x1c#define SNVS_LPSRTCLR		0x20#define SNVS_LPTAR		0x24#define SNVS_LPPGDR		0x30 #define SNVS_LPCR_SRTC_ENV	(1 << 0)#define SNVS_LPCR_LPTA_EN	(1 << 1)#define SNVS_LPCR_LPWUI_EN	(1 << 3)#define SNVS_LPSR_LPTA		(1 << 0) #define SNVS_LPPGDR_INIT	0x41736166#define CNTR_TO_SECS_SH		15 /* The maximum RTC clock cycles that are allowed to pass between two * consecutive clock counter register reads. If the values are corrupted a * bigger difference is expected. The RTC frequency is 32kHz. With 320 cycles * we end at 10ms which should be enough for most cases. If it once takes * longer than expected we do a retry. */#define MAX_RTC_READ_DIFF_CYCLES	320 struct snvs_rtc_data {	struct rtc_device *rtc;	struct regmap *regmap;	int offset;	int irq;	struct clk *clk;}; /* Read 64 bit timer register, which could be in inconsistent state */static u64 rtc_read_lpsrt(struct snvs_rtc_data *data){	u32 msb, lsb; 	regmap_read(data->regmap, data->offset + SNVS_LPSRTCMR, &msb);	regmap_read(data->regmap, data->offset + SNVS_LPSRTCLR, &lsb);	return (u64)msb << 32 | lsb;} /* Read the secure real time counter, taking care to deal with the cases of the * counter updating while being read. */static u32 rtc_read_lp_counter(struct snvs_rtc_data *data){	u64 read1, read2;	s64 diff;	unsigned int timeout = 100; 	/* As expected, the registers might update between the read of the LSB	 * reg and the MSB reg.  It's also possible that one register might be	 * in partially modified state as well.	 */	read1 = rtc_read_lpsrt(data);	do {		read2 = read1;		read1 = rtc_read_lpsrt(data);		diff = read1 - read2;	} while (((diff < 0) || (diff > MAX_RTC_READ_DIFF_CYCLES)) && --timeout);	if (!timeout)		dev_err(&data->rtc->dev, "Timeout trying to get valid LPSRT Counter read\n"); 	/* Convert 47-bit counter to 32-bit raw second count */	return (u32) (read1 >> CNTR_TO_SECS_SH);} /* Just read the lsb from the counter, dealing with inconsistent state */static int rtc_read_lp_counter_lsb(struct snvs_rtc_data *data, u32 *lsb){	u32 count1, count2;	s32 diff;	unsigned int timeout = 100; 	regmap_read(data->regmap, data->offset + SNVS_LPSRTCLR, &count1);	do {		count2 = count1;		regmap_read(data->regmap, data->offset + SNVS_LPSRTCLR, &count1);		diff = count1 - count2;	} while (((diff < 0) || (diff > MAX_RTC_READ_DIFF_CYCLES)) && --timeout);	if (!timeout) {		dev_err(&data->rtc->dev, "Timeout trying to get valid LPSRT Counter read\n");		return -ETIMEDOUT;	} 	*lsb = count1;	return 0;} static int rtc_write_sync_lp(struct snvs_rtc_data *data){	u32 count1, count2;	u32 elapsed;	unsigned int timeout = 1000;	int ret; 	ret = rtc_read_lp_counter_lsb(data, &count1);	if (ret)		return ret; 	/* Wait for 3 CKIL cycles, about 61.0-91.5 µs */	do {		ret = rtc_read_lp_counter_lsb(data, &count2);		if (ret)			return ret;		elapsed = count2 - count1; /* wrap around _is_ handled! */	} while (elapsed < 3 && --timeout);	if (!timeout) {		dev_err(&data->rtc->dev, "Timeout waiting for LPSRT Counter to change\n");		return -ETIMEDOUT;	}	return 0;} static int snvs_rtc_enable(struct snvs_rtc_data *data, bool enable){	int timeout = 1000;	u32 lpcr; 	regmap_update_bits(data->regmap, data->offset + SNVS_LPCR, SNVS_LPCR_SRTC_ENV,			   enable ? SNVS_LPCR_SRTC_ENV : 0); 	while (--timeout) {		regmap_read(data->regmap, data->offset + SNVS_LPCR, &lpcr); 		if (enable) {			if (lpcr & SNVS_LPCR_SRTC_ENV)				break;		} else {			if (!(lpcr & SNVS_LPCR_SRTC_ENV))				break;		}	} 	if (!timeout)		return -ETIMEDOUT; 	return 0;} static int snvs_rtc_read_time(struct device *dev, struct rtc_time *tm){	struct snvs_rtc_data *data = dev_get_drvdata(dev);	unsigned long time;	int ret; 	ret = clk_enable(data->clk);	if (ret)		return ret; 	time = rtc_read_lp_counter(data);	rtc_time64_to_tm(time, tm); 	clk_disable(data->clk); 	return 0;} static int snvs_rtc_set_time(struct device *dev, struct rtc_time *tm){	struct snvs_rtc_data *data = dev_get_drvdata(dev);	unsigned long time = rtc_tm_to_time64(tm);	int ret; 	ret = clk_enable(data->clk);	if (ret)		return ret; 	/* Disable RTC first */	ret = snvs_rtc_enable(data, false);	if (ret)		return ret; 	/* Write 32-bit time to 47-bit timer, leaving 15 LSBs blank */	regmap_write(data->regmap, data->offset + SNVS_LPSRTCLR, time << CNTR_TO_SECS_SH);	regmap_write(data->regmap, data->offset + SNVS_LPSRTCMR, time >> (32 - CNTR_TO_SECS_SH)); 	/* Enable RTC again */	ret = snvs_rtc_enable(data, true); 	clk_disable(data->clk); 	return ret;} static int snvs_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm){	struct snvs_rtc_data *data = dev_get_drvdata(dev);	u32 lptar, lpsr;	int ret; 	ret = clk_enable(data->clk);	if (ret)		return ret; 	regmap_read(data->regmap, data->offset + SNVS_LPTAR, &lptar);	rtc_time64_to_tm(lptar, &alrm->time); 	regmap_read(data->regmap, data->offset + SNVS_LPSR, &lpsr);	alrm->pending = (lpsr & SNVS_LPSR_LPTA) ? 1 : 0; 	clk_disable(data->clk); 	return 0;} static int snvs_rtc_alarm_irq_enable(struct device *dev, unsigned int enable){	struct snvs_rtc_data *data = dev_get_drvdata(dev);	int ret; 	ret = clk_enable(data->clk);	if (ret)		return ret; 	regmap_update_bits(data->regmap, data->offset + SNVS_LPCR,			   (SNVS_LPCR_LPTA_EN | SNVS_LPCR_LPWUI_EN),			   enable ? (SNVS_LPCR_LPTA_EN | SNVS_LPCR_LPWUI_EN) : 0); 	ret = rtc_write_sync_lp(data); 	clk_disable(data->clk); 	return ret;} static int snvs_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm){	struct snvs_rtc_data *data = dev_get_drvdata(dev);	unsigned long time = rtc_tm_to_time64(&alrm->time);	int ret; 	ret = clk_enable(data->clk);	if (ret)		return ret; 	regmap_update_bits(data->regmap, data->offset + SNVS_LPCR, SNVS_LPCR_LPTA_EN, 0);	ret = rtc_write_sync_lp(data);	if (ret)		return ret;	regmap_write(data->regmap, data->offset + SNVS_LPTAR, time); 	/* Clear alarm interrupt status bit */	regmap_write(data->regmap, data->offset + SNVS_LPSR, SNVS_LPSR_LPTA); 	clk_disable(data->clk); 	return snvs_rtc_alarm_irq_enable(dev, alrm->enabled);} static const struct rtc_class_ops snvs_rtc_ops = {	.read_time = snvs_rtc_read_time,	.set_time = snvs_rtc_set_time,	.read_alarm = snvs_rtc_read_alarm,	.set_alarm = snvs_rtc_set_alarm,	.alarm_irq_enable = snvs_rtc_alarm_irq_enable,}; static irqreturn_t snvs_rtc_irq_handler(int irq, void *dev_id){	struct device *dev = dev_id;	struct snvs_rtc_data *data = dev_get_drvdata(dev);	u32 lpsr;	u32 events = 0; 	clk_enable(data->clk); 	regmap_read(data->regmap, data->offset + SNVS_LPSR, &lpsr); 	if (lpsr & SNVS_LPSR_LPTA) {		events |= (RTC_AF | RTC_IRQF); 		/* RTC alarm should be one-shot */		snvs_rtc_alarm_irq_enable(dev, 0); 		rtc_update_irq(data->rtc, 1, events);	} 	/* clear interrupt status */	regmap_write(data->regmap, data->offset + SNVS_LPSR, lpsr); 	clk_disable(data->clk); 	return events ? IRQ_HANDLED : IRQ_NONE;} static const struct regmap_config snvs_rtc_config = {	.reg_bits = 32,	.val_bits = 32,	.reg_stride = 4,}; static void snvs_rtc_action(void *data){	clk_disable_unprepare(data);} static int snvs_rtc_probe(struct platform_device *pdev){	struct snvs_rtc_data *data;	int ret;	void __iomem *mmio; 	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);	if (!data)		return -ENOMEM; 	data->rtc = devm_rtc_allocate_device(&pdev->dev);	if (IS_ERR(data->rtc))		return PTR_ERR(data->rtc); 	data->regmap = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, "regmap"); 	if (IS_ERR(data->regmap)) {		dev_warn(&pdev->dev, "snvs rtc: you use old dts file, please update it\n"); 		mmio = devm_platform_ioremap_resource(pdev, 0);		if (IS_ERR(mmio))			return PTR_ERR(mmio); 		data->regmap = devm_regmap_init_mmio(&pdev->dev, mmio, &snvs_rtc_config);	} else {		data->offset = SNVS_LPREGISTER_OFFSET;		of_property_read_u32(pdev->dev.of_node, "offset", &data->offset);	} 	if (IS_ERR(data->regmap)) {		dev_err(&pdev->dev, "Can't find snvs syscon\n");		return -ENODEV;	} 	data->irq = platform_get_irq(pdev, 0);	if (data->irq < 0)		return data->irq; 	data->clk = devm_clk_get(&pdev->dev, "snvs-rtc");	if (IS_ERR(data->clk)) {		data->clk = NULL;	} else {		ret = clk_prepare_enable(data->clk);		if (ret) {			dev_err(&pdev->dev,				"Could not prepare or enable the snvs clock\n");			return ret;		}	} 	ret = devm_add_action_or_reset(&pdev->dev, snvs_rtc_action, data->clk);	if (ret)		return ret; 	platform_set_drvdata(pdev, data); 	/* Initialize glitch detect */	regmap_write(data->regmap, data->offset + SNVS_LPPGDR, SNVS_LPPGDR_INIT); 	/* Clear interrupt status */	regmap_write(data->regmap, data->offset + SNVS_LPSR, 0xffffffff); 	/* Enable RTC */	ret = snvs_rtc_enable(data, true);	if (ret) {		dev_err(&pdev->dev, "failed to enable rtc %d\n", ret);		return ret;	} 	device_init_wakeup(&pdev->dev, true);	ret = dev_pm_set_wake_irq(&pdev->dev, data->irq);	if (ret)		dev_err(&pdev->dev, "failed to enable irq wake\n"); 	ret = devm_request_irq(&pdev->dev, data->irq, snvs_rtc_irq_handler,			       IRQF_SHARED, "rtc alarm", &pdev->dev);	if (ret) {		dev_err(&pdev->dev, "failed to request irq %d: %d\n",			data->irq, ret);		return ret;	} 	data->rtc->ops = &snvs_rtc_ops;	data->rtc->range_max = U32_MAX; 	return devm_rtc_register_device(data->rtc);} static int __maybe_unused snvs_rtc_suspend_noirq(struct device *dev){	struct snvs_rtc_data *data = dev_get_drvdata(dev); 	clk_disable(data->clk); 	return 0;} static int __maybe_unused snvs_rtc_resume_noirq(struct device *dev){	struct snvs_rtc_data *data = dev_get_drvdata(dev); 	if (data->clk)		return clk_enable(data->clk); 	return 0;} static const struct dev_pm_ops snvs_rtc_pm_ops = {	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(snvs_rtc_suspend_noirq, snvs_rtc_resume_noirq)}; static const struct of_device_id snvs_dt_ids[] = {	{ .compatible = "fsl,sec-v4.0-mon-rtc-lp", },	{ /* sentinel */ }};MODULE_DEVICE_TABLE(of, snvs_dt_ids); static struct platform_driver snvs_rtc_driver = {	.driver = {		.name	= "snvs_rtc",		.pm	= &snvs_rtc_pm_ops,		.of_match_table = snvs_dt_ids,	},	.probe		= snvs_rtc_probe,};module_platform_driver(snvs_rtc_driver); MODULE_AUTHOR("Freescale Semiconductor, Inc.");MODULE_DESCRIPTION("Freescale SNVS RTC Driver");MODULE_LICENSE("GPL");