Commit c89ac918 authored by Yiting Deng's avatar Yiting Deng Committed by Alexandre Belloni
Browse files

rtc: support for the Amlogic on-chip RTC 



This is the third amlogic driver. The RTC hardware of A4 SoC is different
from the previous one. This RTC hardware includes a timing function and
an alarm function. But the existing has only timing function, alarm
function is using the system clock to implement a virtual alarm. Add
the RTC driver to support it.

Signed-off-by: default avatarYiting Deng <yiting.deng@amlogic.com>
Signed-off-by: default avatarXianwei Zhao <xianwei.zhao@amlogic.com>
Link: https://lore.kernel.org/r/20241112-rtc-v6-2-a71b60d2f354@amlogic.com


Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@bootlin.com>
parent ce57cf73

drivers/rtc/Kconfig

+12 −0
Original line number Diff line number Diff line
@@ -2091,4 +2091,16 @@ 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_AMLOGIC_A4

	tristate "Amlogic RTC"

	depends on ARCH_MESON || COMPILE_TEST

	select REGMAP_MMIO

	default y

	help

	  If you say yes here you get support for the RTC block on the

	  Amlogic A113L2(A4) and A113X2(A5) SoCs.



	  This driver can also be built as a module. If so, the module

	  will be called "rtc-amlogic-a4".



endif # RTC_CLASS

drivers/rtc/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ obj-$(CONFIG_RTC_DRV_ABB5ZES3) += rtc-ab-b5ze-s3.o 
obj-$(CONFIG_RTC_DRV_ABEOZ9)	+= rtc-ab-eoz9.o

obj-$(CONFIG_RTC_DRV_ABX80X)	+= rtc-abx80x.o

obj-$(CONFIG_RTC_DRV_AC100)	+= rtc-ac100.o

obj-$(CONFIG_RTC_DRV_AMLOGIC_A4)	+= rtc-amlogic-a4.o

obj-$(CONFIG_RTC_DRV_ARMADA38X)	+= rtc-armada38x.o

obj-$(CONFIG_RTC_DRV_AS3722)	+= rtc-as3722.o

obj-$(CONFIG_RTC_DRV_ASM9260)	+= rtc-asm9260.o

drivers/rtc/rtc-amlogic-a4.c

0 → 100644
+474 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: (GPL-2.0-only OR MIT)

/*

 * Copyright (C) 2024 Amlogic, Inc. All rights reserved

 * Author: Yiting Deng <yiting.deng@amlogic.com>

 */



#include <linux/bitfield.h>

#include <linux/clk.h>

#include <linux/clk-provider.h>

#include <linux/delay.h>

#include <linux/module.h>

#include <linux/platform_device.h>

#include <linux/regmap.h>

#include <linux/rtc.h>

#include <linux/time64.h>



/* rtc oscillator rate */

#define OSC_32K			32768

#define OSC_24M			24000000



#define RTC_CTRL		(0x0 << 2)		/* Control RTC */

#define RTC_ALRM0_EN		BIT(0)

#define RTC_OSC_SEL		BIT(8)

#define RTC_ENABLE		BIT(12)



#define RTC_COUNTER_REG		(0x1 << 2)		/* Program RTC counter initial value */



#define RTC_ALARM0_REG		(0x2 << 2)		/* Program RTC alarm0 value */



#define RTC_SEC_ADJUST_REG	(0x6 << 2)		/* Control second-based timing adjustment */

#define RTC_MATCH_COUNTER	GENMASK(18, 0)

#define RTC_SEC_ADJUST_CTRL	GENMASK(20, 19)

#define RTC_ADJ_VALID		BIT(23)



#define RTC_INT_MASK		(0x8 << 2)		/* RTC interrupt mask */

#define RTC_ALRM0_IRQ_MSK	BIT(0)



#define RTC_INT_CLR		(0x9 << 2)		/* Clear RTC interrupt */

#define RTC_ALRM0_IRQ_CLR	BIT(0)



#define RTC_OSCIN_CTRL0		(0xa << 2)		/* Control RTC clk from 24M */

#define RTC_OSCIN_CTRL1		(0xb << 2)		/* Control RTC clk from 24M */

#define RTC_OSCIN_IN_EN		BIT(31)

#define RTC_OSCIN_OUT_CFG	GENMASK(29, 28)

#define RTC_OSCIN_OUT_N0M0	GENMASK(11, 0)

#define RTC_OSCIN_OUT_N1M1	GENMASK(23, 12)



#define RTC_INT_STATUS		(0xc << 2)		/* RTC interrupt status */

#define RTC_ALRM0_IRQ_STATUS	BIT(0)



#define RTC_REAL_TIME		(0xd << 2)		/* RTC time value */



#define RTC_OSCIN_OUT_32K_N0	0x2dc

#define RTC_OSCIN_OUT_32K_N1	0x2db

#define RTC_OSCIN_OUT_32K_M0	0x1

#define RTC_OSCIN_OUT_32K_M1	0x2



#define RTC_SWALLOW_SECOND	0x2

#define RTC_INSERT_SECOND	0x3



struct aml_rtc_config {

	bool gray_stored;

};



struct aml_rtc_data {

	struct regmap *map;

	struct rtc_device *rtc_dev;

	int irq;

	struct clk *rtc_clk;

	struct clk *sys_clk;

	int rtc_enabled;

	const struct aml_rtc_config *config;

};



static const struct regmap_config aml_rtc_regmap_config = {

	.reg_bits = 32,

	.val_bits = 32,

	.reg_stride = 4,

	.max_register = RTC_REAL_TIME,

};



static inline u32 gray_to_binary(u32 gray)

{

	u32 bcd = gray;

	int size = sizeof(bcd) * 8;

	int i;



	for (i = 0; (1 << i) < size; i++)

		bcd ^= bcd >> (1 << i);



	return bcd;

}



static inline u32 binary_to_gray(u32 bcd)

{

	return bcd ^ (bcd >> 1);

}



static int aml_rtc_read_time(struct device *dev, struct rtc_time *tm)

{

	struct aml_rtc_data *rtc = dev_get_drvdata(dev);

	u32 time_sec;



	/* if RTC disabled, read time failed */

	if (!rtc->rtc_enabled) {

		dev_err(dev, "RTC disabled, read time failed\n");

		return -EINVAL;

	}



	regmap_read(rtc->map, RTC_REAL_TIME, &time_sec);

	if (rtc->config->gray_stored)

		time_sec = gray_to_binary(time_sec);

	rtc_time64_to_tm(time_sec, tm);

	dev_dbg(dev, "%s: read time = %us\n", __func__, time_sec);



	return 0;

}



static int aml_rtc_set_time(struct device *dev, struct rtc_time *tm)

{

	struct aml_rtc_data *rtc = dev_get_drvdata(dev);

	u32 time_sec;



	/* if RTC disabled, first enable it */

	if (!rtc->rtc_enabled) {

		regmap_write_bits(rtc->map, RTC_CTRL, RTC_ENABLE, RTC_ENABLE);

		usleep_range(100, 200);

		rtc->rtc_enabled = regmap_test_bits(rtc->map, RTC_CTRL, RTC_ENABLE);

		if (!rtc->rtc_enabled)

			return -EINVAL;

	}



	time_sec = rtc_tm_to_time64(tm);

	if (rtc->config->gray_stored)

		time_sec = binary_to_gray(time_sec);

	regmap_write(rtc->map, RTC_COUNTER_REG, time_sec);

	dev_dbg(dev, "%s: set time = %us\n", __func__, time_sec);



	return 0;

}



static int aml_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)

{

	struct aml_rtc_data *rtc = dev_get_drvdata(dev);

	time64_t alarm_sec;



	/* if RTC disabled, set alarm failed */

	if (!rtc->rtc_enabled) {

		dev_err(dev, "RTC disabled, set alarm failed\n");

		return -EINVAL;

	}



	regmap_update_bits(rtc->map, RTC_CTRL,

			   RTC_ALRM0_EN, RTC_ALRM0_EN);

	regmap_update_bits(rtc->map, RTC_INT_MASK,

			   RTC_ALRM0_IRQ_MSK, 0);



	alarm_sec = rtc_tm_to_time64(&alarm->time);

	if (rtc->config->gray_stored)

		alarm_sec = binary_to_gray(alarm_sec);

	regmap_write(rtc->map, RTC_ALARM0_REG, alarm_sec);



	dev_dbg(dev, "%s: alarm->enabled=%d alarm_set=%llds\n", __func__,

		alarm->enabled, alarm_sec);



	return 0;

}



static int aml_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)

{

	struct aml_rtc_data *rtc = dev_get_drvdata(dev);

	u32 alarm_sec;

	int alarm_enable;

	int alarm_mask;



	/* if RTC disabled, read alarm failed */

	if (!rtc->rtc_enabled) {

		dev_err(dev, "RTC disabled, read alarm failed\n");

		return -EINVAL;

	}



	regmap_read(rtc->map, RTC_ALARM0_REG, &alarm_sec);

	if (rtc->config->gray_stored)

		alarm_sec = gray_to_binary(alarm_sec);

	rtc_time64_to_tm(alarm_sec, &alarm->time);



	alarm_enable = regmap_test_bits(rtc->map, RTC_CTRL, RTC_ALRM0_EN);

	alarm_mask = regmap_test_bits(rtc->map, RTC_INT_MASK, RTC_ALRM0_IRQ_MSK);

	alarm->enabled = (alarm_enable && !alarm_mask) ? 1 : 0;

	dev_dbg(dev, "%s: alarm->enabled=%d alarm=%us\n", __func__,

		alarm->enabled, alarm_sec);



	return 0;

}



static int aml_rtc_read_offset(struct device *dev, long *offset)

{

	struct aml_rtc_data *rtc = dev_get_drvdata(dev);

	u32 reg_val;

	long val;

	int sign, match_counter, enable;



	/* if RTC disabled, read offset failed */

	if (!rtc->rtc_enabled) {

		dev_err(dev, "RTC disabled, read offset failed\n");

		return -EINVAL;

	}



	regmap_read(rtc->map, RTC_SEC_ADJUST_REG, &reg_val);

	enable = FIELD_GET(RTC_ADJ_VALID, reg_val);

	if (!enable) {

		val = 0;

	} else {

		sign = FIELD_GET(RTC_SEC_ADJUST_CTRL, reg_val);

		match_counter = FIELD_GET(RTC_MATCH_COUNTER, reg_val);

		val = 1000000000 / (match_counter + 1);

		if (sign == RTC_SWALLOW_SECOND)

			val = -val;

	}

	*offset = val;



	return 0;

}



static int aml_rtc_set_offset(struct device *dev, long offset)

{

	struct aml_rtc_data *rtc = dev_get_drvdata(dev);

	int sign = 0;

	int match_counter = 0;

	int enable = 0;

	u32 reg_val;



	/* if RTC disabled, set offset failed */

	if (!rtc->rtc_enabled) {

		dev_err(dev, "RTC disabled, set offset failed\n");

		return -EINVAL;

	}



	if (offset) {

		enable = 1;

		sign = offset < 0 ? RTC_SWALLOW_SECOND : RTC_INSERT_SECOND;

		match_counter = 1000000000 / abs(offset) - 1;

		if (match_counter < 0 || match_counter > RTC_MATCH_COUNTER)

			return -EINVAL;

	}



	reg_val = FIELD_PREP(RTC_ADJ_VALID, enable) |

		  FIELD_PREP(RTC_SEC_ADJUST_CTRL, sign) |

		  FIELD_PREP(RTC_MATCH_COUNTER, match_counter);

	regmap_write(rtc->map, RTC_SEC_ADJUST_REG, reg_val);



	return 0;

}



static int aml_rtc_alarm_enable(struct device *dev, unsigned int enabled)

{

	struct aml_rtc_data *rtc = dev_get_drvdata(dev);



	if (enabled) {

		regmap_update_bits(rtc->map, RTC_CTRL,

				   RTC_ALRM0_EN, RTC_ALRM0_EN);

		regmap_update_bits(rtc->map, RTC_INT_MASK,

				   RTC_ALRM0_IRQ_MSK, 0);

	} else {

		regmap_update_bits(rtc->map, RTC_INT_MASK,

				   RTC_ALRM0_IRQ_MSK, RTC_ALRM0_IRQ_MSK);

		regmap_update_bits(rtc->map, RTC_CTRL,

				   RTC_ALRM0_EN, 0);

	}



	return 0;

}



static const struct rtc_class_ops aml_rtc_ops = {

	.read_time = aml_rtc_read_time,

	.set_time = aml_rtc_set_time,

	.read_alarm = aml_rtc_read_alarm,

	.set_alarm = aml_rtc_set_alarm,

	.alarm_irq_enable = aml_rtc_alarm_enable,

	.read_offset = aml_rtc_read_offset,

	.set_offset = aml_rtc_set_offset,

};



static irqreturn_t aml_rtc_handler(int irq, void *data)

{

	struct aml_rtc_data *rtc = (struct aml_rtc_data *)data;



	regmap_write(rtc->map, RTC_ALARM0_REG, 0);

	regmap_write(rtc->map, RTC_INT_CLR, RTC_ALRM0_IRQ_STATUS);



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



	return IRQ_HANDLED;

}



static void aml_rtc_init(struct aml_rtc_data *rtc)

{

	u32 reg_val = 0;



	rtc->rtc_enabled = regmap_test_bits(rtc->map, RTC_CTRL, RTC_ENABLE);

	if (!rtc->rtc_enabled) {

		if (clk_get_rate(rtc->rtc_clk) == OSC_24M) {

			/* select 24M oscillator */

			regmap_write_bits(rtc->map, RTC_CTRL, RTC_OSC_SEL, RTC_OSC_SEL);



			/*

			 * Set RTC oscillator to freq_out to freq_in/((N0*M0+N1*M1)/(M0+M1))

			 * Enable clock_in gate of oscillator 24MHz

			 * Set N0 to 733, N1 to 732

			 */

			reg_val = FIELD_PREP(RTC_OSCIN_IN_EN, 1)

				  | FIELD_PREP(RTC_OSCIN_OUT_CFG, 1)

				  | FIELD_PREP(RTC_OSCIN_OUT_N0M0, RTC_OSCIN_OUT_32K_N0)

				  | FIELD_PREP(RTC_OSCIN_OUT_N1M1, RTC_OSCIN_OUT_32K_N1);

			regmap_write_bits(rtc->map, RTC_OSCIN_CTRL0, RTC_OSCIN_IN_EN

					  | RTC_OSCIN_OUT_CFG | RTC_OSCIN_OUT_N0M0

					  | RTC_OSCIN_OUT_N1M1, reg_val);



			/* Set M0 to 2, M1 to 3, so freq_out = 32768 Hz*/

			reg_val = FIELD_PREP(RTC_OSCIN_OUT_N0M0, RTC_OSCIN_OUT_32K_M0)

				  | FIELD_PREP(RTC_OSCIN_OUT_N1M1, RTC_OSCIN_OUT_32K_M1);

			regmap_write_bits(rtc->map, RTC_OSCIN_CTRL1, RTC_OSCIN_OUT_N0M0

					  | RTC_OSCIN_OUT_N1M1, reg_val);

		} else {

			/* select 32K oscillator */

			regmap_write_bits(rtc->map, RTC_CTRL, RTC_OSC_SEL, 0);

		}

	}

	regmap_write_bits(rtc->map, RTC_INT_MASK,

			  RTC_ALRM0_IRQ_MSK, RTC_ALRM0_IRQ_MSK);

	regmap_write_bits(rtc->map, RTC_CTRL, RTC_ALRM0_EN, 0);

}



static int aml_rtc_probe(struct platform_device *pdev)

{

	struct device *dev = &pdev->dev;

	struct aml_rtc_data *rtc;

	void __iomem *base;

	int ret = 0;



	rtc = devm_kzalloc(dev, sizeof(*rtc), GFP_KERNEL);

	if (!rtc)

		return -ENOMEM;



	rtc->config = of_device_get_match_data(dev);

	if (!rtc->config)

		return -ENODEV;



	base = devm_platform_ioremap_resource(pdev, 0);

	if (IS_ERR(base))

		return dev_err_probe(dev, PTR_ERR(base), "resource ioremap failed\n");



	rtc->map = devm_regmap_init_mmio(dev, base, &aml_rtc_regmap_config);

	if (IS_ERR(rtc->map))

		return dev_err_probe(dev, PTR_ERR(rtc->map), "regmap init failed\n");



	rtc->irq = platform_get_irq(pdev, 0);

	if (rtc->irq < 0)

		return rtc->irq;



	rtc->rtc_clk = devm_clk_get(dev, "osc");

	if (IS_ERR(rtc->rtc_clk))

		return dev_err_probe(dev, PTR_ERR(rtc->rtc_clk),

				     "failed to find rtc clock\n");

	if (clk_get_rate(rtc->rtc_clk) != OSC_32K && clk_get_rate(rtc->rtc_clk) != OSC_24M)

		return dev_err_probe(dev, -EINVAL, "Invalid clock configuration\n");



	rtc->sys_clk = devm_clk_get_enabled(dev, "sys");

	if (IS_ERR(rtc->sys_clk))

		return dev_err_probe(dev, PTR_ERR(rtc->sys_clk),

				     "failed to get_enable rtc sys clk\n");

	aml_rtc_init(rtc);



	device_init_wakeup(dev, 1);

	platform_set_drvdata(pdev, rtc);



	rtc->rtc_dev = devm_rtc_allocate_device(dev);

	if (IS_ERR(rtc->rtc_dev)) {

		ret = PTR_ERR(rtc->rtc_dev);

		goto err_clk;

	}



	ret = devm_request_irq(dev, rtc->irq, aml_rtc_handler,

			       IRQF_ONESHOT, "aml-rtc alarm", rtc);

	if (ret) {

		dev_err_probe(dev, ret, "IRQ%d request failed, ret = %d\n",

			      rtc->irq, ret);

		goto err_clk;

	}



	rtc->rtc_dev->ops = &aml_rtc_ops;

	rtc->rtc_dev->range_min = 0;

	rtc->rtc_dev->range_max = U32_MAX;



	ret = devm_rtc_register_device(rtc->rtc_dev);

	if (ret) {

		dev_err_probe(&pdev->dev, ret, "Failed to register RTC device: %d\n", ret);

		goto err_clk;

	}



	return 0;

err_clk:

	clk_disable_unprepare(rtc->sys_clk);

	device_init_wakeup(dev, 0);



	return ret;

}



#ifdef CONFIG_PM_SLEEP

static int aml_rtc_suspend(struct device *dev)

{

	struct aml_rtc_data *rtc = dev_get_drvdata(dev);



	if (device_may_wakeup(dev))

		enable_irq_wake(rtc->irq);



	return 0;

}



static int aml_rtc_resume(struct device *dev)

{

	struct aml_rtc_data *rtc = dev_get_drvdata(dev);



	if (device_may_wakeup(dev))

		disable_irq_wake(rtc->irq);



	return 0;

}

#endif



static SIMPLE_DEV_PM_OPS(aml_rtc_pm_ops,

			 aml_rtc_suspend, aml_rtc_resume);



static void aml_rtc_remove(struct platform_device *pdev)

{

	struct aml_rtc_data *rtc = dev_get_drvdata(&pdev->dev);



	clk_disable_unprepare(rtc->sys_clk);

	device_init_wakeup(&pdev->dev, 0);

}



static const struct aml_rtc_config a5_rtc_config = {

};



static const struct aml_rtc_config a4_rtc_config = {

	.gray_stored = true,

};



static const struct of_device_id aml_rtc_device_id[] = {

	{

		.compatible = "amlogic,a4-rtc",

		.data = &a4_rtc_config,

	},

	{

		.compatible = "amlogic,a5-rtc",

		.data = &a5_rtc_config,

	},

};

MODULE_DEVICE_TABLE(of, aml_rtc_device_id);



static struct platform_driver aml_rtc_driver = {

	.probe = aml_rtc_probe,

	.remove = aml_rtc_remove,

	.driver = {

		.name = "aml-rtc",

		.pm = &aml_rtc_pm_ops,

		.of_match_table = aml_rtc_device_id,

	},

};



module_platform_driver(aml_rtc_driver);

MODULE_DESCRIPTION("Amlogic RTC driver");

MODULE_AUTHOR("Yiting Deng <yiting.deng@amlogic.com>");

MODULE_LICENSE("GPL");