drivers/rtc/rtc-sunplus.c - linux/kernel/git/torvalds/linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0

 /*
  * The RTC driver for Sunplus	SP7021
  *
  * Copyright (C) 2019 Sunplus Technology Inc., All rights reseerved.
  */

 #include <linux/bitfield.h>
 #include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/io.h>
 #include <linux/ktime.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/reset.h>
 #include <linux/rtc.h>

 #define RTC_REG_NAME			"rtc"

 #define RTC_CTRL			0x40
 #define TIMER_FREEZE_MASK_BIT		BIT(5 + 16)
 #define TIMER_FREEZE			BIT(5)
 #define DIS_SYS_RST_RTC_MASK_BIT	BIT(4 + 16)
 #define DIS_SYS_RST_RTC			BIT(4)
 #define RTC32K_MODE_RESET_MASK_BIT	BIT(3 + 16)
 #define RTC32K_MODE_RESET		BIT(3)
 #define ALARM_EN_OVERDUE_MASK_BIT	BIT(2 + 16)
 #define ALARM_EN_OVERDUE		BIT(2)
 #define ALARM_EN_PMC_MASK_BIT		BIT(1 + 16)
 #define ALARM_EN_PMC			BIT(1)
 #define ALARM_EN_MASK_BIT		BIT(0 + 16)
 #define ALARM_EN			BIT(0)
 #define RTC_TIMER_OUT			0x44
 #define RTC_DIVIDER			0x48
 #define RTC_TIMER_SET			0x4c
 #define RTC_ALARM_SET			0x50
 #define RTC_USER_DATA			0x54
 #define RTC_RESET_RECORD		0x58
 #define RTC_BATT_CHARGE_CTRL		0x5c
 #define BAT_CHARGE_RSEL_MASK_BIT	GENMASK(3 + 16, 2 + 16)
 #define BAT_CHARGE_RSEL_MASK		GENMASK(3, 2)
 #define BAT_CHARGE_RSEL_2K_OHM		FIELD_PREP(BAT_CHARGE_RSEL_MASK, 0)
 #define BAT_CHARGE_RSEL_250_OHM		FIELD_PREP(BAT_CHARGE_RSEL_MASK, 1)
 #define BAT_CHARGE_RSEL_50_OHM		FIELD_PREP(BAT_CHARGE_RSEL_MASK, 2)
 #define BAT_CHARGE_RSEL_0_OHM		FIELD_PREP(BAT_CHARGE_RSEL_MASK, 3)
 #define BAT_CHARGE_DSEL_MASK_BIT	BIT(1 + 16)
 #define BAT_CHARGE_DSEL_MASK		GENMASK(1, 1)
 #define BAT_CHARGE_DSEL_ON		FIELD_PREP(BAT_CHARGE_DSEL_MASK, 0)
 #define BAT_CHARGE_DSEL_OFF		FIELD_PREP(BAT_CHARGE_DSEL_MASK, 1)
 #define BAT_CHARGE_EN_MASK_BIT		BIT(0 + 16)
 #define BAT_CHARGE_EN			BIT(0)
 #define RTC_TRIM_CTRL			0x60

 struct sunplus_rtc {
 	struct rtc_device *rtc;
 	struct resource *res;
 	struct clk *rtcclk;
 	struct reset_control *rstc;
 	void __iomem *reg_base;
 	int irq;
 };

 static void sp_get_seconds(struct device *dev, unsigned long *secs)
 {
 	struct sunplus_rtc *sp_rtc = dev_get_drvdata(dev);

 	*secs = (unsigned long)readl(sp_rtc->reg_base + RTC_TIMER_OUT);
 }

 static void sp_set_seconds(struct device *dev, unsigned long secs)
 {
 	struct sunplus_rtc *sp_rtc = dev_get_drvdata(dev);

 	writel((u32)secs, sp_rtc->reg_base + RTC_TIMER_SET);
 }

 static int sp_rtc_read_time(struct device *dev, struct rtc_time *tm)
 {
 	unsigned long secs;

 	sp_get_seconds(dev, &secs);
 	rtc_time64_to_tm(secs, tm);

 	return 0;
 }

 static int sp_rtc_set_time(struct device *dev, struct rtc_time *tm)
 {
 	unsigned long secs;

 	secs = rtc_tm_to_time64(tm);
 	dev_dbg(dev, "%s, secs = %lu\n", __func__, secs);
 	sp_set_seconds(dev, secs);

 	return 0;
 }

 static int sp_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 {
 	struct sunplus_rtc *sp_rtc = dev_get_drvdata(dev);
 	unsigned long alarm_time;

 	alarm_time = rtc_tm_to_time64(&alrm->time);
 	dev_dbg(dev, "%s, alarm_time: %u\n", __func__, (u32)(alarm_time));
 	writel((u32)alarm_time, sp_rtc->reg_base + RTC_ALARM_SET);

 	return 0;
 }

 static int sp_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 {
 	struct sunplus_rtc *sp_rtc = dev_get_drvdata(dev);
 	unsigned int alarm_time;

 	alarm_time = readl(sp_rtc->reg_base + RTC_ALARM_SET);
 	dev_dbg(dev, "%s, alarm_time: %u\n", __func__, alarm_time);

 	if (alarm_time == 0)
 		alrm->enabled = 0;
 	else
 		alrm->enabled = 1;

 	rtc_time64_to_tm((unsigned long)(alarm_time), &alrm->time);

 	return 0;
 }

 static int sp_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 {
 	struct sunplus_rtc *sp_rtc = dev_get_drvdata(dev);

 	if (enabled)
 		writel((TIMER_FREEZE_MASK_BIT | DIS_SYS_RST_RTC_MASK_BIT |
 			RTC32K_MODE_RESET_MASK_BIT | ALARM_EN_OVERDUE_MASK_BIT |
 			ALARM_EN_PMC_MASK_BIT | ALARM_EN_MASK_BIT) |
 			(DIS_SYS_RST_RTC | ALARM_EN_OVERDUE | ALARM_EN_PMC | ALARM_EN),
 			sp_rtc->reg_base + RTC_CTRL);
 	else
 		writel((ALARM_EN_OVERDUE_MASK_BIT | ALARM_EN_PMC_MASK_BIT | ALARM_EN_MASK_BIT) |
 			0x0, sp_rtc->reg_base + RTC_CTRL);

 	return 0;
 }

 static const struct rtc_class_ops sp_rtc_ops = {
 	.read_time =		sp_rtc_read_time,
 	.set_time =		sp_rtc_set_time,
 	.set_alarm =		sp_rtc_set_alarm,
 	.read_alarm =		sp_rtc_read_alarm,
 	.alarm_irq_enable =	sp_rtc_alarm_irq_enable,
 };

 static irqreturn_t sp_rtc_irq_handler(int irq, void *dev_id)
 {
 	struct platform_device *plat_dev = dev_id;
 	struct sunplus_rtc *sp_rtc = dev_get_drvdata(&plat_dev->dev);

 	rtc_update_irq(sp_rtc->rtc, 1, RTC_IRQF | RTC_AF);
 	dev_dbg(&plat_dev->dev, "[RTC] ALARM INT\n");

 	return IRQ_HANDLED;
 }

 /*
  * -------------------------------------------------------------------------------------
  * bat_charge_rsel   bat_charge_dsel   bat_charge_en     Remarks
  *         x              x                 0            Disable
  *         0              0                 1            0.86mA (2K Ohm with diode)
  *         1              0                 1            1.81mA (250 Ohm with diode)
  *         2              0                 1            2.07mA (50 Ohm with diode)
  *         3              0                 1            16.0mA (0 Ohm with diode)
  *         0              1                 1            1.36mA (2K Ohm without diode)
  *         1              1                 1            3.99mA (250 Ohm without diode)
  *         2              1                 1            4.41mA (50 Ohm without diode)
  *         3              1                 1            16.0mA (0 Ohm without diode)
  * -------------------------------------------------------------------------------------
  */
 static void sp_rtc_set_trickle_charger(struct device dev)
 {
 	struct sunplus_rtc *sp_rtc = dev_get_drvdata(&dev);
 	u32 ohms, rsel;
 	u32 chargeable;

 	if (of_property_read_u32(dev.of_node, "trickle-resistor-ohms", &ohms) ||
 	    of_property_read_u32(dev.of_node, "aux-voltage-chargeable", &chargeable)) {
 		dev_warn(&dev, "battery charger disabled\n");
 		return;
 	}

 	switch (ohms) {
 	case 2000:
 		rsel = BAT_CHARGE_RSEL_2K_OHM;
 		break;
 	case 250:
 		rsel = BAT_CHARGE_RSEL_250_OHM;
 		break;
 	case 50:
 		rsel = BAT_CHARGE_RSEL_50_OHM;
 		break;
 	case 0:
 		rsel = BAT_CHARGE_RSEL_0_OHM;
 		break;
 	default:
 		dev_err(&dev, "invalid charger resistor value (%d)\n", ohms);
 		return;
 	}

 	writel(BAT_CHARGE_RSEL_MASK_BIT | rsel, sp_rtc->reg_base + RTC_BATT_CHARGE_CTRL);

 	switch (chargeable) {
 	case 0:
 		writel(BAT_CHARGE_DSEL_MASK_BIT | BAT_CHARGE_DSEL_OFF,
 		       sp_rtc->reg_base + RTC_BATT_CHARGE_CTRL);
 		break;
 	case 1:
 		writel(BAT_CHARGE_DSEL_MASK_BIT | BAT_CHARGE_DSEL_ON,
 		       sp_rtc->reg_base + RTC_BATT_CHARGE_CTRL);
 		break;
 	default:
 		dev_err(&dev, "invalid aux-voltage-chargeable value (%d)\n", chargeable);
 		return;
 	}

 	writel(BAT_CHARGE_EN_MASK_BIT | BAT_CHARGE_EN, sp_rtc->reg_base + RTC_BATT_CHARGE_CTRL);
 }

 static int sp_rtc_probe(struct platform_device *plat_dev)
 {
 	struct sunplus_rtc *sp_rtc;
 	int ret;

 	sp_rtc = devm_kzalloc(&plat_dev->dev, sizeof(*sp_rtc), GFP_KERNEL);
 	if (!sp_rtc)
 		return -ENOMEM;

 	sp_rtc->res = platform_get_resource_byname(plat_dev, IORESOURCE_MEM, RTC_REG_NAME);
 	sp_rtc->reg_base = devm_ioremap_resource(&plat_dev->dev, sp_rtc->res);
 	if (IS_ERR(sp_rtc->reg_base))
 		return dev_err_probe(&plat_dev->dev, PTR_ERR(sp_rtc->reg_base),
 					    "%s devm_ioremap_resource fail\n", RTC_REG_NAME);
 	dev_dbg(&plat_dev->dev, "res = 0x%x, reg_base = 0x%lx\n",
 		sp_rtc->res->start, (unsigned long)sp_rtc->reg_base);

 	sp_rtc->irq = platform_get_irq(plat_dev, 0);
 	if (sp_rtc->irq < 0)
 		return dev_err_probe(&plat_dev->dev, sp_rtc->irq, "platform_get_irq failed\n");

 	ret = devm_request_irq(&plat_dev->dev, sp_rtc->irq, sp_rtc_irq_handler,
 			       IRQF_TRIGGER_RISING, "rtc irq", plat_dev);
 	if (ret)
 		return dev_err_probe(&plat_dev->dev, ret, "devm_request_irq failed:\n");

 	sp_rtc->rtcclk = devm_clk_get(&plat_dev->dev, NULL);
 	if (IS_ERR(sp_rtc->rtcclk))
 		return dev_err_probe(&plat_dev->dev, PTR_ERR(sp_rtc->rtcclk),
 					    "devm_clk_get fail\n");

 	sp_rtc->rstc = devm_reset_control_get_exclusive(&plat_dev->dev, NULL);
 	if (IS_ERR(sp_rtc->rstc))
 		return dev_err_probe(&plat_dev->dev, PTR_ERR(sp_rtc->rstc),
 					    "failed to retrieve reset controller\n");

 	ret = clk_prepare_enable(sp_rtc->rtcclk);
 	if (ret)
 		goto free_clk;

 	ret = reset_control_deassert(sp_rtc->rstc);
 	if (ret)
 		goto free_reset_assert;

 	device_init_wakeup(&plat_dev->dev, 1);
 	dev_set_drvdata(&plat_dev->dev, sp_rtc);

 	sp_rtc->rtc = devm_rtc_allocate_device(&plat_dev->dev);
 	if (IS_ERR(sp_rtc->rtc)) {
 		ret = PTR_ERR(sp_rtc->rtc);
 		goto free_reset_assert;
 	}

 	sp_rtc->rtc->range_max = U32_MAX;
 	sp_rtc->rtc->range_min = 0;
 	sp_rtc->rtc->ops = &sp_rtc_ops;

 	ret = devm_rtc_register_device(sp_rtc->rtc);
 	if (ret)
 		goto free_reset_assert;

 	/* Setup trickle charger */
 	if (plat_dev->dev.of_node)
 		sp_rtc_set_trickle_charger(plat_dev->dev);

 	/* Keep RTC from system reset */
 	writel(DIS_SYS_RST_RTC_MASK_BIT | DIS_SYS_RST_RTC, sp_rtc->reg_base + RTC_CTRL);

 	return 0;

 free_reset_assert:
 	reset_control_assert(sp_rtc->rstc);
 free_clk:
 	clk_disable_unprepare(sp_rtc->rtcclk);

 	return ret;
 }

 static int sp_rtc_remove(struct platform_device *plat_dev)
 {
 	struct sunplus_rtc *sp_rtc = dev_get_drvdata(&plat_dev->dev);

 	device_init_wakeup(&plat_dev->dev, 0);
 	reset_control_assert(sp_rtc->rstc);
 	clk_disable_unprepare(sp_rtc->rtcclk);

 	return 0;
 }

 #ifdef CONFIG_PM_SLEEP
 static int sp_rtc_suspend(struct device *dev)
 {
 	struct sunplus_rtc *sp_rtc = dev_get_drvdata(dev);

 	if (device_may_wakeup(dev))
 		enable_irq_wake(sp_rtc->irq);

 	return 0;
 }

 static int sp_rtc_resume(struct device *dev)
 {
 	struct sunplus_rtc *sp_rtc = dev_get_drvdata(dev);

 	if (device_may_wakeup(dev))
 		disable_irq_wake(sp_rtc->irq);

 	return 0;
 }
 #endif

 static const struct of_device_id sp_rtc_of_match[] = {
 	{ .compatible = "sunplus,sp7021-rtc" },
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, sp_rtc_of_match);

 static SIMPLE_DEV_PM_OPS(sp_rtc_pm_ops, sp_rtc_suspend, sp_rtc_resume);

 static struct platform_driver sp_rtc_driver = {
 	.probe   = sp_rtc_probe,
 	.remove  = sp_rtc_remove,
 	.driver  = {
 		.name	= "sp7021-rtc",
 		.of_match_table = sp_rtc_of_match,
 		.pm	= &sp_rtc_pm_ops,
 	},
 };
 module_platform_driver(sp_rtc_driver);

 MODULE_AUTHOR("Vincent Shih <vincent.sunplus@gmail.com>");
 MODULE_DESCRIPTION("Sunplus RTC driver");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0

	/*
	* The RTC driver for Sunplus SP7021
	*
	* Copyright (C) 2019 Sunplus Technology Inc., All rights reseerved.
	*/

	#include <linux/bitfield.h>
	#include <linux/clk.h>
	#include <linux/err.h>
	#include <linux/io.h>
	#include <linux/ktime.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/platform_device.h>
	#include <linux/reset.h>
	#include <linux/rtc.h>

	#define RTC_REG_NAME "rtc"

	#define RTC_CTRL 0x40
	#define TIMER_FREEZE_MASK_BIT BIT(5 + 16)
	#define TIMER_FREEZE BIT(5)
	#define DIS_SYS_RST_RTC_MASK_BIT BIT(4 + 16)
	#define DIS_SYS_RST_RTC BIT(4)
	#define RTC32K_MODE_RESET_MASK_BIT BIT(3 + 16)
	#define RTC32K_MODE_RESET BIT(3)
	#define ALARM_EN_OVERDUE_MASK_BIT BIT(2 + 16)
	#define ALARM_EN_OVERDUE BIT(2)
	#define ALARM_EN_PMC_MASK_BIT BIT(1 + 16)
	#define ALARM_EN_PMC BIT(1)
	#define ALARM_EN_MASK_BIT BIT(0 + 16)
	#define ALARM_EN BIT(0)
	#define RTC_TIMER_OUT 0x44
	#define RTC_DIVIDER 0x48
	#define RTC_TIMER_SET 0x4c
	#define RTC_ALARM_SET 0x50
	#define RTC_USER_DATA 0x54
	#define RTC_RESET_RECORD 0x58
	#define RTC_BATT_CHARGE_CTRL 0x5c
	#define BAT_CHARGE_RSEL_MASK_BIT GENMASK(3 + 16, 2 + 16)
	#define BAT_CHARGE_RSEL_MASK GENMASK(3, 2)
	#define BAT_CHARGE_RSEL_2K_OHM FIELD_PREP(BAT_CHARGE_RSEL_MASK, 0)
	#define BAT_CHARGE_RSEL_250_OHM FIELD_PREP(BAT_CHARGE_RSEL_MASK, 1)
	#define BAT_CHARGE_RSEL_50_OHM FIELD_PREP(BAT_CHARGE_RSEL_MASK, 2)
	#define BAT_CHARGE_RSEL_0_OHM FIELD_PREP(BAT_CHARGE_RSEL_MASK, 3)
	#define BAT_CHARGE_DSEL_MASK_BIT BIT(1 + 16)
	#define BAT_CHARGE_DSEL_MASK GENMASK(1, 1)
	#define BAT_CHARGE_DSEL_ON FIELD_PREP(BAT_CHARGE_DSEL_MASK, 0)
	#define BAT_CHARGE_DSEL_OFF FIELD_PREP(BAT_CHARGE_DSEL_MASK, 1)
	#define BAT_CHARGE_EN_MASK_BIT BIT(0 + 16)
	#define BAT_CHARGE_EN BIT(0)
	#define RTC_TRIM_CTRL 0x60

	struct sunplus_rtc {
	struct rtc_device *rtc;
	struct resource *res;
	struct clk *rtcclk;
	struct reset_control *rstc;
	void __iomem *reg_base;
	int irq;
	};

	static void sp_get_seconds(struct device dev, unsigned long secs)
	{
	struct sunplus_rtc *sp_rtc = dev_get_drvdata(dev);

	*secs = (unsigned long)readl(sp_rtc->reg_base + RTC_TIMER_OUT);
	}

	static void sp_set_seconds(struct device *dev, unsigned long secs)
	{
	struct sunplus_rtc *sp_rtc = dev_get_drvdata(dev);

	writel((u32)secs, sp_rtc->reg_base + RTC_TIMER_SET);
	}

	static int sp_rtc_read_time(struct device dev, struct rtc_time tm)
	{
	unsigned long secs;

	sp_get_seconds(dev, &secs);
	rtc_time64_to_tm(secs, tm);

	return 0;
	}

	static int sp_rtc_set_time(struct device dev, struct rtc_time tm)
	{
	unsigned long secs;

	secs = rtc_tm_to_time64(tm);
	dev_dbg(dev, "%s, secs = %lu\n", __func__, secs);
	sp_set_seconds(dev, secs);

	return 0;
	}

	static int sp_rtc_set_alarm(struct device dev, struct rtc_wkalrm alrm)
	{
	struct sunplus_rtc *sp_rtc = dev_get_drvdata(dev);
	unsigned long alarm_time;

	alarm_time = rtc_tm_to_time64(&alrm->time);
	dev_dbg(dev, "%s, alarm_time: %u\n", __func__, (u32)(alarm_time));
	writel((u32)alarm_time, sp_rtc->reg_base + RTC_ALARM_SET);

	return 0;
	}

	static int sp_rtc_read_alarm(struct device dev, struct rtc_wkalrm alrm)
	{
	struct sunplus_rtc *sp_rtc = dev_get_drvdata(dev);
	unsigned int alarm_time;

	alarm_time = readl(sp_rtc->reg_base + RTC_ALARM_SET);
	dev_dbg(dev, "%s, alarm_time: %u\n", __func__, alarm_time);

	if (alarm_time == 0)
	alrm->enabled = 0;
	else
	alrm->enabled = 1;

	rtc_time64_to_tm((unsigned long)(alarm_time), &alrm->time);

	return 0;
	}

	static int sp_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
	{
	struct sunplus_rtc *sp_rtc = dev_get_drvdata(dev);

	if (enabled)
	writel((TIMER_FREEZE_MASK_BIT \| DIS_SYS_RST_RTC_MASK_BIT \|
	RTC32K_MODE_RESET_MASK_BIT \| ALARM_EN_OVERDUE_MASK_BIT \|
	ALARM_EN_PMC_MASK_BIT \| ALARM_EN_MASK_BIT) \|
	(DIS_SYS_RST_RTC \| ALARM_EN_OVERDUE \| ALARM_EN_PMC \| ALARM_EN),
	sp_rtc->reg_base + RTC_CTRL);
	else
	writel((ALARM_EN_OVERDUE_MASK_BIT \| ALARM_EN_PMC_MASK_BIT \| ALARM_EN_MASK_BIT) \|
	0x0, sp_rtc->reg_base + RTC_CTRL);

	return 0;
	}

	static const struct rtc_class_ops sp_rtc_ops = {
	.read_time = sp_rtc_read_time,
	.set_time = sp_rtc_set_time,
	.set_alarm = sp_rtc_set_alarm,
	.read_alarm = sp_rtc_read_alarm,
	.alarm_irq_enable = sp_rtc_alarm_irq_enable,
	};

	static irqreturn_t sp_rtc_irq_handler(int irq, void *dev_id)
	{
	struct platform_device *plat_dev = dev_id;
	struct sunplus_rtc *sp_rtc = dev_get_drvdata(&plat_dev->dev);

	rtc_update_irq(sp_rtc->rtc, 1, RTC_IRQF \| RTC_AF);
	dev_dbg(&plat_dev->dev, "[RTC] ALARM INT\n");

	return IRQ_HANDLED;
	}

	/*
	* -------------------------------------------------------------------------------------
	* bat_charge_rsel bat_charge_dsel bat_charge_en Remarks
	* x x 0 Disable
	* 0 0 1 0.86mA (2K Ohm with diode)
	* 1 0 1 1.81mA (250 Ohm with diode)
	* 2 0 1 2.07mA (50 Ohm with diode)
	* 3 0 1 16.0mA (0 Ohm with diode)
	* 0 1 1 1.36mA (2K Ohm without diode)
	* 1 1 1 3.99mA (250 Ohm without diode)
	* 2 1 1 4.41mA (50 Ohm without diode)
	* 3 1 1 16.0mA (0 Ohm without diode)
	* -------------------------------------------------------------------------------------
	*/
	static void sp_rtc_set_trickle_charger(struct device dev)
	{
	struct sunplus_rtc *sp_rtc = dev_get_drvdata(&dev);
	u32 ohms, rsel;
	u32 chargeable;

	if (of_property_read_u32(dev.of_node, "trickle-resistor-ohms", &ohms) \|\|
	of_property_read_u32(dev.of_node, "aux-voltage-chargeable", &chargeable)) {
	dev_warn(&dev, "battery charger disabled\n");
	return;
	}

	switch (ohms) {
	case 2000:
	rsel = BAT_CHARGE_RSEL_2K_OHM;
	break;
	case 250:
	rsel = BAT_CHARGE_RSEL_250_OHM;
	break;
	case 50:
	rsel = BAT_CHARGE_RSEL_50_OHM;
	break;
	case 0:
	rsel = BAT_CHARGE_RSEL_0_OHM;
	break;
	default:
	dev_err(&dev, "invalid charger resistor value (%d)\n", ohms);
	return;
	}

	writel(BAT_CHARGE_RSEL_MASK_BIT \| rsel, sp_rtc->reg_base + RTC_BATT_CHARGE_CTRL);

	switch (chargeable) {
	case 0:
	writel(BAT_CHARGE_DSEL_MASK_BIT \| BAT_CHARGE_DSEL_OFF,
	sp_rtc->reg_base + RTC_BATT_CHARGE_CTRL);
	break;
	case 1:
	writel(BAT_CHARGE_DSEL_MASK_BIT \| BAT_CHARGE_DSEL_ON,
	sp_rtc->reg_base + RTC_BATT_CHARGE_CTRL);
	break;
	default:
	dev_err(&dev, "invalid aux-voltage-chargeable value (%d)\n", chargeable);
	return;
	}

	writel(BAT_CHARGE_EN_MASK_BIT \| BAT_CHARGE_EN, sp_rtc->reg_base + RTC_BATT_CHARGE_CTRL);
	}

	static int sp_rtc_probe(struct platform_device *plat_dev)
	{
	struct sunplus_rtc *sp_rtc;
	int ret;

	sp_rtc = devm_kzalloc(&plat_dev->dev, sizeof(*sp_rtc), GFP_KERNEL);
	if (!sp_rtc)
	return -ENOMEM;

	sp_rtc->res = platform_get_resource_byname(plat_dev, IORESOURCE_MEM, RTC_REG_NAME);
	sp_rtc->reg_base = devm_ioremap_resource(&plat_dev->dev, sp_rtc->res);
	if (IS_ERR(sp_rtc->reg_base))
	return dev_err_probe(&plat_dev->dev, PTR_ERR(sp_rtc->reg_base),
	"%s devm_ioremap_resource fail\n", RTC_REG_NAME);
	dev_dbg(&plat_dev->dev, "res = 0x%x, reg_base = 0x%lx\n",
	sp_rtc->res->start, (unsigned long)sp_rtc->reg_base);

	sp_rtc->irq = platform_get_irq(plat_dev, 0);
	if (sp_rtc->irq < 0)
	return dev_err_probe(&plat_dev->dev, sp_rtc->irq, "platform_get_irq failed\n");

	ret = devm_request_irq(&plat_dev->dev, sp_rtc->irq, sp_rtc_irq_handler,
	IRQF_TRIGGER_RISING, "rtc irq", plat_dev);
	if (ret)
	return dev_err_probe(&plat_dev->dev, ret, "devm_request_irq failed:\n");

	sp_rtc->rtcclk = devm_clk_get(&plat_dev->dev, NULL);
	if (IS_ERR(sp_rtc->rtcclk))
	return dev_err_probe(&plat_dev->dev, PTR_ERR(sp_rtc->rtcclk),
	"devm_clk_get fail\n");

	sp_rtc->rstc = devm_reset_control_get_exclusive(&plat_dev->dev, NULL);
	if (IS_ERR(sp_rtc->rstc))
	return dev_err_probe(&plat_dev->dev, PTR_ERR(sp_rtc->rstc),
	"failed to retrieve reset controller\n");

	ret = clk_prepare_enable(sp_rtc->rtcclk);
	if (ret)
	goto free_clk;

	ret = reset_control_deassert(sp_rtc->rstc);
	if (ret)
	goto free_reset_assert;

	device_init_wakeup(&plat_dev->dev, 1);
	dev_set_drvdata(&plat_dev->dev, sp_rtc);

	sp_rtc->rtc = devm_rtc_allocate_device(&plat_dev->dev);
	if (IS_ERR(sp_rtc->rtc)) {
	ret = PTR_ERR(sp_rtc->rtc);
	goto free_reset_assert;
	}

	sp_rtc->rtc->range_max = U32_MAX;
	sp_rtc->rtc->range_min = 0;
	sp_rtc->rtc->ops = &sp_rtc_ops;

	ret = devm_rtc_register_device(sp_rtc->rtc);
	if (ret)
	goto free_reset_assert;

	/* Setup trickle charger */
	if (plat_dev->dev.of_node)
	sp_rtc_set_trickle_charger(plat_dev->dev);

	/* Keep RTC from system reset */
	writel(DIS_SYS_RST_RTC_MASK_BIT \| DIS_SYS_RST_RTC, sp_rtc->reg_base + RTC_CTRL);

	return 0;

	free_reset_assert:
	reset_control_assert(sp_rtc->rstc);
	free_clk:
	clk_disable_unprepare(sp_rtc->rtcclk);

	return ret;
	}

	static int sp_rtc_remove(struct platform_device *plat_dev)
	{
	struct sunplus_rtc *sp_rtc = dev_get_drvdata(&plat_dev->dev);

	device_init_wakeup(&plat_dev->dev, 0);
	reset_control_assert(sp_rtc->rstc);
	clk_disable_unprepare(sp_rtc->rtcclk);

	return 0;
	}

	#ifdef CONFIG_PM_SLEEP
	static int sp_rtc_suspend(struct device *dev)
	{
	struct sunplus_rtc *sp_rtc = dev_get_drvdata(dev);

	if (device_may_wakeup(dev))
	enable_irq_wake(sp_rtc->irq);

	return 0;
	}

	static int sp_rtc_resume(struct device *dev)
	{
	struct sunplus_rtc *sp_rtc = dev_get_drvdata(dev);

	if (device_may_wakeup(dev))
	disable_irq_wake(sp_rtc->irq);

	return 0;
	}
	#endif

	static const struct of_device_id sp_rtc_of_match[] = {
	{ .compatible = "sunplus,sp7021-rtc" },
	{ /* sentinel */ }
	};
	MODULE_DEVICE_TABLE(of, sp_rtc_of_match);

	static SIMPLE_DEV_PM_OPS(sp_rtc_pm_ops, sp_rtc_suspend, sp_rtc_resume);

	static struct platform_driver sp_rtc_driver = {
	.probe = sp_rtc_probe,
	.remove = sp_rtc_remove,
	.driver = {
	.name = "sp7021-rtc",
	.of_match_table = sp_rtc_of_match,
	.pm = &sp_rtc_pm_ops,
	},
	};
	module_platform_driver(sp_rtc_driver);

	MODULE_AUTHOR("Vincent Shih <vincent.sunplus@gmail.com>");
	MODULE_DESCRIPTION("Sunplus RTC driver");
	MODULE_LICENSE("GPL v2");