drivers/rtc/rtc-fsl-ftm-alarm.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * Freescale FlexTimer Module (FTM) alarm device driver.
  *
  * Copyright 2014 Freescale Semiconductor, Inc.
  * Copyright 2019-2020 NXP
  *
  */

 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
 #include <linux/platform_device.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/module.h>
 #include <linux/fsl/ftm.h>
 #include <linux/rtc.h>
 #include <linux/time.h>
 #include <linux/acpi.h>
 #include <linux/pm_wakeirq.h>

 #define FTM_SC_CLK(c)		((c) << FTM_SC_CLK_MASK_SHIFT)

 /*
  * Select Fixed frequency clock (32KHz) as clock source
  * of FlexTimer Module
  */
 #define FTM_SC_CLKS_FIXED_FREQ	0x02
 #define FIXED_FREQ_CLK		32000

 /* Select 128 (2^7) as divider factor */
 #define MAX_FREQ_DIV		(1 << FTM_SC_PS_MASK)

 /* Maximum counter value in FlexTimer's CNT registers */
 #define MAX_COUNT_VAL		0xffff

 struct ftm_rtc {
 	struct rtc_device *rtc_dev;
 	void __iomem *base;
 	bool big_endian;
 	u32 alarm_freq;
 };

 static inline u32 rtc_readl(struct ftm_rtc *dev, u32 reg)
 {
 	if (dev->big_endian)
 		return ioread32be(dev->base + reg);
 	else
 		return ioread32(dev->base + reg);
 }

 static inline void rtc_writel(struct ftm_rtc *dev, u32 reg, u32 val)
 {
 	if (dev->big_endian)
 		iowrite32be(val, dev->base + reg);
 	else
 		iowrite32(val, dev->base + reg);
 }

 static inline void ftm_counter_enable(struct ftm_rtc *rtc)
 {
 	u32 val;

 	/* select and enable counter clock source */
 	val = rtc_readl(rtc, FTM_SC);
 	val &= ~(FTM_SC_PS_MASK | FTM_SC_CLK_MASK);
 	val |= (FTM_SC_PS_MASK | FTM_SC_CLK(FTM_SC_CLKS_FIXED_FREQ));
 	rtc_writel(rtc, FTM_SC, val);
 }

 static inline void ftm_counter_disable(struct ftm_rtc *rtc)
 {
 	u32 val;

 	/* disable counter clock source */
 	val = rtc_readl(rtc, FTM_SC);
 	val &= ~(FTM_SC_PS_MASK | FTM_SC_CLK_MASK);
 	rtc_writel(rtc, FTM_SC, val);
 }

 static inline void ftm_irq_acknowledge(struct ftm_rtc *rtc)
 {
 	unsigned int timeout = 100;

 	/*
 	 *Fix errata A-007728 for flextimer
 	 *	If the FTM counter reaches the FTM_MOD value between
 	 *	the reading of the TOF bit and the writing of 0 to
 	 *	the TOF bit, the process of clearing the TOF bit
 	 *	does not work as expected when FTMx_CONF[NUMTOF] != 0
 	 *	and the current TOF count is less than FTMx_CONF[NUMTOF].
 	 *	If the above condition is met, the TOF bit remains set.
 	 *	If the TOF interrupt is enabled (FTMx_SC[TOIE] = 1),the
 	 *	TOF interrupt also remains asserted.
 	 *
 	 *	Above is the errata discription
 	 *
 	 *	In one word: software clearing TOF bit not works when
 	 *	FTMx_CONF[NUMTOF] was seted as nonzero and FTM counter
 	 *	reaches the FTM_MOD value.
 	 *
 	 *	The workaround is clearing TOF bit until it works
 	 *	(FTM counter doesn't always reache the FTM_MOD anyway),
 	 *	which may cost some cycles.
 	 */
 	while ((FTM_SC_TOF & rtc_readl(rtc, FTM_SC)) && timeout--)
 		rtc_writel(rtc, FTM_SC, rtc_readl(rtc, FTM_SC) & (~FTM_SC_TOF));
 }

 static inline void ftm_irq_enable(struct ftm_rtc *rtc)
 {
 	u32 val;

 	val = rtc_readl(rtc, FTM_SC);
 	val |= FTM_SC_TOIE;
 	rtc_writel(rtc, FTM_SC, val);
 }

 static inline void ftm_irq_disable(struct ftm_rtc *rtc)
 {
 	u32 val;

 	val = rtc_readl(rtc, FTM_SC);
 	val &= ~FTM_SC_TOIE;
 	rtc_writel(rtc, FTM_SC, val);
 }

 static inline void ftm_reset_counter(struct ftm_rtc *rtc)
 {
 	/*
 	 * The CNT register contains the FTM counter value.
 	 * Reset clears the CNT register. Writing any value to COUNT
 	 * updates the counter with its initial value, CNTIN.
 	 */
 	rtc_writel(rtc, FTM_CNT, 0x00);
 }

 static void ftm_clean_alarm(struct ftm_rtc *rtc)
 {
 	ftm_counter_disable(rtc);

 	rtc_writel(rtc, FTM_CNTIN, 0x00);
 	rtc_writel(rtc, FTM_MOD, ~0U);

 	ftm_reset_counter(rtc);
 }

 static irqreturn_t ftm_rtc_alarm_interrupt(int irq, void *dev)
 {
 	struct ftm_rtc *rtc = dev;

 	rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF | RTC_AF);

 	ftm_irq_acknowledge(rtc);
 	ftm_irq_disable(rtc);
 	ftm_clean_alarm(rtc);

 	return IRQ_HANDLED;
 }

 static int ftm_rtc_alarm_irq_enable(struct device *dev,
 		unsigned int enabled)
 {
 	struct ftm_rtc *rtc = dev_get_drvdata(dev);

 	if (enabled)
 		ftm_irq_enable(rtc);
 	else
 		ftm_irq_disable(rtc);

 	return 0;
 }

 /*
  * Note:
  *	The function is not really getting time from the RTC
  *	since FlexTimer is not a RTC device, but we need to
  *	get time to setup alarm, so we are using system time
  *	for now.
  */
 static int ftm_rtc_read_time(struct device *dev, struct rtc_time *tm)
 {
 	rtc_time64_to_tm(ktime_get_real_seconds(), tm);

 	return 0;
 }

 static int ftm_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 {
 	return 0;
 }

 /*
  * 1. Select fixed frequency clock (32KHz) as clock source;
  * 2. Select 128 (2^7) as divider factor;
  * So clock is 250 Hz (32KHz/128).
  *
  * 3. FlexTimer's CNT register is a 32bit register,
  * but the register's 16 bit as counter value,it's other 16 bit
  * is reserved.So minimum counter value is 0x0,maximum counter
  * value is 0xffff.
  * So max alarm value is 262 (65536 / 250) seconds
  */
 static int ftm_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 {
 	time64_t alm_time;
 	unsigned long long cycle;
 	struct ftm_rtc *rtc = dev_get_drvdata(dev);

 	alm_time = rtc_tm_to_time64(&alm->time);

 	ftm_clean_alarm(rtc);
 	cycle = (alm_time - ktime_get_real_seconds()) * rtc->alarm_freq;
 	if (cycle > MAX_COUNT_VAL) {
 		pr_err("Out of alarm range {0~262} seconds.\n");
 		return -ERANGE;
 	}

 	ftm_irq_disable(rtc);

 	/*
 	 * The counter increments until the value of MOD is reached,
 	 * at which point the counter is reloaded with the value of CNTIN.
 	 * The TOF (the overflow flag) bit is set when the FTM counter
 	 * changes from MOD to CNTIN. So we should using the cycle - 1.
 	 */
 	rtc_writel(rtc, FTM_MOD, cycle - 1);

 	ftm_counter_enable(rtc);
 	ftm_irq_enable(rtc);

 	return 0;

 }

 static const struct rtc_class_ops ftm_rtc_ops = {
 	.read_time		= ftm_rtc_read_time,
 	.read_alarm		= ftm_rtc_read_alarm,
 	.set_alarm		= ftm_rtc_set_alarm,
 	.alarm_irq_enable	= ftm_rtc_alarm_irq_enable,
 };

 static int ftm_rtc_probe(struct platform_device *pdev)
 {
 	int irq;
 	int ret;
 	struct ftm_rtc *rtc;

 	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
 	if (unlikely(!rtc)) {
 		dev_err(&pdev->dev, "cannot alloc memory for rtc\n");
 		return -ENOMEM;
 	}

 	platform_set_drvdata(pdev, rtc);

 	rtc->rtc_dev = devm_rtc_allocate_device(&pdev->dev);
 	if (IS_ERR(rtc->rtc_dev))
 		return PTR_ERR(rtc->rtc_dev);

 	rtc->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(rtc->base)) {
 		dev_err(&pdev->dev, "cannot ioremap resource for rtc\n");
 		return PTR_ERR(rtc->base);
 	}

 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0)
 		return irq;

 	ret = devm_request_irq(&pdev->dev, irq, ftm_rtc_alarm_interrupt,
 			       0, dev_name(&pdev->dev), rtc);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "failed to request irq\n");
 		return ret;
 	}

 	rtc->big_endian =
 		device_property_read_bool(&pdev->dev, "big-endian");

 	rtc->alarm_freq = (u32)FIXED_FREQ_CLK / (u32)MAX_FREQ_DIV;
 	rtc->rtc_dev->ops = &ftm_rtc_ops;

 	device_init_wakeup(&pdev->dev, true);
 	ret = dev_pm_set_wake_irq(&pdev->dev, irq);
 	if (ret)
 		dev_err(&pdev->dev, "failed to enable irq wake\n");

 	ret = rtc_register_device(rtc->rtc_dev);
 	if (ret) {
 		dev_err(&pdev->dev, "can't register rtc device\n");
 		return ret;
 	}

 	return 0;
 }

 static const struct of_device_id ftm_rtc_match[] = {
 	{ .compatible = "fsl,ls1012a-ftm-alarm", },
 	{ .compatible = "fsl,ls1021a-ftm-alarm", },
 	{ .compatible = "fsl,ls1028a-ftm-alarm", },
 	{ .compatible = "fsl,ls1043a-ftm-alarm", },
 	{ .compatible = "fsl,ls1046a-ftm-alarm", },
 	{ .compatible = "fsl,ls1088a-ftm-alarm", },
 	{ .compatible = "fsl,ls208xa-ftm-alarm", },
 	{ .compatible = "fsl,lx2160a-ftm-alarm", },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, ftm_rtc_match);

 static const struct acpi_device_id ftm_imx_acpi_ids[] = {
 	{"NXP0014",},
 	{ }
 };
 MODULE_DEVICE_TABLE(acpi, ftm_imx_acpi_ids);

 static struct platform_driver ftm_rtc_driver = {
 	.probe		= ftm_rtc_probe,
 	.driver		= {
 		.name	= "ftm-alarm",
 		.of_match_table = ftm_rtc_match,
 		.acpi_match_table = ACPI_PTR(ftm_imx_acpi_ids),
 	},
 };

 static int __init ftm_alarm_init(void)
 {
 	return platform_driver_register(&ftm_rtc_driver);
 }

 device_initcall(ftm_alarm_init);

 MODULE_DESCRIPTION("NXP/Freescale FlexTimer alarm driver");
 MODULE_AUTHOR("Biwen Li <biwen.li@nxp.com>");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* Freescale FlexTimer Module (FTM) alarm device driver.
	*
	* Copyright 2014 Freescale Semiconductor, Inc.
	* Copyright 2019-2020 NXP
	*
	*/

	#include <linux/device.h>
	#include <linux/err.h>
	#include <linux/interrupt.h>
	#include <linux/io.h>
	#include <linux/of_address.h>
	#include <linux/of_irq.h>
	#include <linux/platform_device.h>
	#include <linux/of.h>
	#include <linux/of_device.h>
	#include <linux/module.h>
	#include <linux/fsl/ftm.h>
	#include <linux/rtc.h>
	#include <linux/time.h>
	#include <linux/acpi.h>
	#include <linux/pm_wakeirq.h>

	#define FTM_SC_CLK(c) ((c) << FTM_SC_CLK_MASK_SHIFT)

	/*
	* Select Fixed frequency clock (32KHz) as clock source
	* of FlexTimer Module
	*/
	#define FTM_SC_CLKS_FIXED_FREQ 0x02
	#define FIXED_FREQ_CLK 32000

	/* Select 128 (2^7) as divider factor */
	#define MAX_FREQ_DIV (1 << FTM_SC_PS_MASK)

	/* Maximum counter value in FlexTimer's CNT registers */
	#define MAX_COUNT_VAL 0xffff

	struct ftm_rtc {
	struct rtc_device *rtc_dev;
	void __iomem *base;
	bool big_endian;
	u32 alarm_freq;
	};

	static inline u32 rtc_readl(struct ftm_rtc *dev, u32 reg)
	{
	if (dev->big_endian)
	return ioread32be(dev->base + reg);
	else
	return ioread32(dev->base + reg);
	}

	static inline void rtc_writel(struct ftm_rtc *dev, u32 reg, u32 val)
	{
	if (dev->big_endian)
	iowrite32be(val, dev->base + reg);
	else
	iowrite32(val, dev->base + reg);
	}

	static inline void ftm_counter_enable(struct ftm_rtc *rtc)
	{
	u32 val;

	/* select and enable counter clock source */
	val = rtc_readl(rtc, FTM_SC);
	val &= ~(FTM_SC_PS_MASK \| FTM_SC_CLK_MASK);
	val \|= (FTM_SC_PS_MASK \| FTM_SC_CLK(FTM_SC_CLKS_FIXED_FREQ));
	rtc_writel(rtc, FTM_SC, val);
	}

	static inline void ftm_counter_disable(struct ftm_rtc *rtc)
	{
	u32 val;

	/* disable counter clock source */
	val = rtc_readl(rtc, FTM_SC);
	val &= ~(FTM_SC_PS_MASK \| FTM_SC_CLK_MASK);
	rtc_writel(rtc, FTM_SC, val);
	}

	static inline void ftm_irq_acknowledge(struct ftm_rtc *rtc)
	{
	unsigned int timeout = 100;

	/*
	*Fix errata A-007728 for flextimer
	* If the FTM counter reaches the FTM_MOD value between
	* the reading of the TOF bit and the writing of 0 to
	* the TOF bit, the process of clearing the TOF bit
	* does not work as expected when FTMx_CONF[NUMTOF] != 0
	* and the current TOF count is less than FTMx_CONF[NUMTOF].
	* If the above condition is met, the TOF bit remains set.
	* If the TOF interrupt is enabled (FTMx_SC[TOIE] = 1),the
	* TOF interrupt also remains asserted.
	*
	* Above is the errata discription
	*
	* In one word: software clearing TOF bit not works when
	* FTMx_CONF[NUMTOF] was seted as nonzero and FTM counter
	* reaches the FTM_MOD value.
	*
	* The workaround is clearing TOF bit until it works
	* (FTM counter doesn't always reache the FTM_MOD anyway),
	* which may cost some cycles.
	*/
	while ((FTM_SC_TOF & rtc_readl(rtc, FTM_SC)) && timeout--)
	rtc_writel(rtc, FTM_SC, rtc_readl(rtc, FTM_SC) & (~FTM_SC_TOF));
	}

	static inline void ftm_irq_enable(struct ftm_rtc *rtc)
	{
	u32 val;

	val = rtc_readl(rtc, FTM_SC);
	val \|= FTM_SC_TOIE;
	rtc_writel(rtc, FTM_SC, val);
	}

	static inline void ftm_irq_disable(struct ftm_rtc *rtc)
	{
	u32 val;

	val = rtc_readl(rtc, FTM_SC);
	val &= ~FTM_SC_TOIE;
	rtc_writel(rtc, FTM_SC, val);
	}

	static inline void ftm_reset_counter(struct ftm_rtc *rtc)
	{
	/*
	* The CNT register contains the FTM counter value.
	* Reset clears the CNT register. Writing any value to COUNT
	* updates the counter with its initial value, CNTIN.
	*/
	rtc_writel(rtc, FTM_CNT, 0x00);
	}

	static void ftm_clean_alarm(struct ftm_rtc *rtc)
	{
	ftm_counter_disable(rtc);

	rtc_writel(rtc, FTM_CNTIN, 0x00);
	rtc_writel(rtc, FTM_MOD, ~0U);

	ftm_reset_counter(rtc);
	}

	static irqreturn_t ftm_rtc_alarm_interrupt(int irq, void *dev)
	{
	struct ftm_rtc *rtc = dev;

	rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF \| RTC_AF);

	ftm_irq_acknowledge(rtc);
	ftm_irq_disable(rtc);
	ftm_clean_alarm(rtc);

	return IRQ_HANDLED;
	}

	static int ftm_rtc_alarm_irq_enable(struct device *dev,
	unsigned int enabled)
	{
	struct ftm_rtc *rtc = dev_get_drvdata(dev);

	if (enabled)
	ftm_irq_enable(rtc);
	else
	ftm_irq_disable(rtc);

	return 0;
	}

	/*
	* Note:
	* The function is not really getting time from the RTC
	* since FlexTimer is not a RTC device, but we need to
	* get time to setup alarm, so we are using system time
	* for now.
	*/
	static int ftm_rtc_read_time(struct device dev, struct rtc_time tm)
	{
	rtc_time64_to_tm(ktime_get_real_seconds(), tm);

	return 0;
	}

	static int ftm_rtc_read_alarm(struct device dev, struct rtc_wkalrm alm)
	{
	return 0;
	}

	/*
	* 1. Select fixed frequency clock (32KHz) as clock source;
	* 2. Select 128 (2^7) as divider factor;
	* So clock is 250 Hz (32KHz/128).
	*
	* 3. FlexTimer's CNT register is a 32bit register,
	* but the register's 16 bit as counter value,it's other 16 bit
	* is reserved.So minimum counter value is 0x0,maximum counter
	* value is 0xffff.
	* So max alarm value is 262 (65536 / 250) seconds
	*/
	static int ftm_rtc_set_alarm(struct device dev, struct rtc_wkalrm alm)
	{
	time64_t alm_time;
	unsigned long long cycle;
	struct ftm_rtc *rtc = dev_get_drvdata(dev);

	alm_time = rtc_tm_to_time64(&alm->time);

	ftm_clean_alarm(rtc);
	cycle = (alm_time - ktime_get_real_seconds()) * rtc->alarm_freq;
	if (cycle > MAX_COUNT_VAL) {
	pr_err("Out of alarm range {0~262} seconds.\n");
	return -ERANGE;
	}

	ftm_irq_disable(rtc);

	/*
	* The counter increments until the value of MOD is reached,
	* at which point the counter is reloaded with the value of CNTIN.
	* The TOF (the overflow flag) bit is set when the FTM counter
	* changes from MOD to CNTIN. So we should using the cycle - 1.
	*/
	rtc_writel(rtc, FTM_MOD, cycle - 1);

	ftm_counter_enable(rtc);
	ftm_irq_enable(rtc);

	return 0;

	}

	static const struct rtc_class_ops ftm_rtc_ops = {
	.read_time = ftm_rtc_read_time,
	.read_alarm = ftm_rtc_read_alarm,
	.set_alarm = ftm_rtc_set_alarm,
	.alarm_irq_enable = ftm_rtc_alarm_irq_enable,
	};

	static int ftm_rtc_probe(struct platform_device *pdev)
	{
	int irq;
	int ret;
	struct ftm_rtc *rtc;

	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
	if (unlikely(!rtc)) {
	dev_err(&pdev->dev, "cannot alloc memory for rtc\n");
	return -ENOMEM;
	}

	platform_set_drvdata(pdev, rtc);

	rtc->rtc_dev = devm_rtc_allocate_device(&pdev->dev);
	if (IS_ERR(rtc->rtc_dev))
	return PTR_ERR(rtc->rtc_dev);

	rtc->base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(rtc->base)) {
	dev_err(&pdev->dev, "cannot ioremap resource for rtc\n");
	return PTR_ERR(rtc->base);
	}

	irq = platform_get_irq(pdev, 0);
	if (irq < 0)
	return irq;

	ret = devm_request_irq(&pdev->dev, irq, ftm_rtc_alarm_interrupt,
	0, dev_name(&pdev->dev), rtc);
	if (ret < 0) {
	dev_err(&pdev->dev, "failed to request irq\n");
	return ret;
	}

	rtc->big_endian =
	device_property_read_bool(&pdev->dev, "big-endian");

	rtc->alarm_freq = (u32)FIXED_FREQ_CLK / (u32)MAX_FREQ_DIV;
	rtc->rtc_dev->ops = &ftm_rtc_ops;

	device_init_wakeup(&pdev->dev, true);
	ret = dev_pm_set_wake_irq(&pdev->dev, irq);
	if (ret)
	dev_err(&pdev->dev, "failed to enable irq wake\n");

	ret = rtc_register_device(rtc->rtc_dev);
	if (ret) {
	dev_err(&pdev->dev, "can't register rtc device\n");
	return ret;
	}

	return 0;
	}

	static const struct of_device_id ftm_rtc_match[] = {
	{ .compatible = "fsl,ls1012a-ftm-alarm", },
	{ .compatible = "fsl,ls1021a-ftm-alarm", },
	{ .compatible = "fsl,ls1028a-ftm-alarm", },
	{ .compatible = "fsl,ls1043a-ftm-alarm", },
	{ .compatible = "fsl,ls1046a-ftm-alarm", },
	{ .compatible = "fsl,ls1088a-ftm-alarm", },
	{ .compatible = "fsl,ls208xa-ftm-alarm", },
	{ .compatible = "fsl,lx2160a-ftm-alarm", },
	{ },
	};
	MODULE_DEVICE_TABLE(of, ftm_rtc_match);

	static const struct acpi_device_id ftm_imx_acpi_ids[] = {
	{"NXP0014",},
	{ }
	};
	MODULE_DEVICE_TABLE(acpi, ftm_imx_acpi_ids);

	static struct platform_driver ftm_rtc_driver = {
	.probe = ftm_rtc_probe,
	.driver = {
	.name = "ftm-alarm",
	.of_match_table = ftm_rtc_match,
	.acpi_match_table = ACPI_PTR(ftm_imx_acpi_ids),
	},
	};

	static int __init ftm_alarm_init(void)
	{
	return platform_driver_register(&ftm_rtc_driver);
	}

	device_initcall(ftm_alarm_init);

	MODULE_DESCRIPTION("NXP/Freescale FlexTimer alarm driver");
	MODULE_AUTHOR("Biwen Li <biwen.li@nxp.com>");
	MODULE_LICENSE("GPL");