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Commit 184a182e authored by Joel Stanley's avatar Joel Stanley Committed by Alexandre Belloni
Browse files

rtc: Add ASPEED RTC driver 



Read and writes the time to the non-battery backed RTC in the ASPEED BMC
system on chip families.

Signed-off-by: default avatarJoel Stanley <joel@jms.id.au>
Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@bootlin.com>
parent e3b37110

drivers/rtc/Kconfig

+11 −0
Original line number Diff line number Diff line
@@ -1841,6 +1841,17 @@ config RTC_DRV_RTD119X 
	  If you say yes here, you get support for the RTD1295 SoC

	  Real Time Clock.



config RTC_DRV_ASPEED

	tristate "ASPEED RTC"

	depends on OF

	depends on ARCH_ASPEED || COMPILE_TEST

	help

	  If you say yes here you get support for the ASPEED BMC SoC real time

	  clocks.



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

	  will be called "rtc-aspeed".



comment "HID Sensor RTC drivers"



config RTC_DRV_HID_SENSOR_TIME

drivers/rtc/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ obj-$(CONFIG_RTC_DRV_AC100) += rtc-ac100.o 
obj-$(CONFIG_RTC_DRV_ARMADA38X)	+= rtc-armada38x.o

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

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

obj-$(CONFIG_RTC_DRV_ASPEED)	+= rtc-aspeed.o

obj-$(CONFIG_RTC_DRV_AT91RM9200)+= rtc-at91rm9200.o

obj-$(CONFIG_RTC_DRV_AT91SAM9)	+= rtc-at91sam9.o

obj-$(CONFIG_RTC_DRV_AU1XXX)	+= rtc-au1xxx.o

drivers/rtc/rtc-aspeed.c

0 → 100644
+136 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0+

// Copyright 2015 IBM Corp.



#include <linux/module.h>

#include <linux/of.h>

#include <linux/platform_device.h>

#include <linux/rtc.h>

#include <linux/io.h>



struct aspeed_rtc {

	struct rtc_device *rtc_dev;

	void __iomem *base;

};



#define RTC_TIME	0x00

#define RTC_YEAR	0x04

#define RTC_CTRL	0x10



#define RTC_UNLOCK	BIT(1)

#define RTC_ENABLE	BIT(0)



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

{

	struct aspeed_rtc *rtc = dev_get_drvdata(dev);

	unsigned int cent, year;

	u32 reg1, reg2;



	if (!(readl(rtc->base + RTC_CTRL) & RTC_ENABLE)) {

		dev_dbg(dev, "%s failing as rtc disabled\n", __func__);

		return -EINVAL;

	}



	do {

		reg2 = readl(rtc->base + RTC_YEAR);

		reg1 = readl(rtc->base + RTC_TIME);

	} while (reg2 != readl(rtc->base + RTC_YEAR));



	tm->tm_mday = (reg1 >> 24) & 0x1f;

	tm->tm_hour = (reg1 >> 16) & 0x1f;

	tm->tm_min = (reg1 >> 8) & 0x3f;

	tm->tm_sec = (reg1 >> 0) & 0x3f;



	cent = (reg2 >> 16) & 0x1f;

	year = (reg2 >> 8) & 0x7f;

	tm->tm_mon = ((reg2 >>  0) & 0x0f) - 1;

	tm->tm_year = year + (cent * 100) - 1900;



	dev_dbg(dev, "%s %ptR", __func__, tm);



	return 0;

}



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

{

	struct aspeed_rtc *rtc = dev_get_drvdata(dev);

	u32 reg1, reg2, ctrl;

	int year, cent;



	cent = (tm->tm_year + 1900) / 100;

	year = tm->tm_year % 100;



	reg1 = (tm->tm_mday << 24) | (tm->tm_hour << 16) | (tm->tm_min << 8) |

		tm->tm_sec;



	reg2 = ((cent & 0x1f) << 16) | ((year & 0x7f) << 8) |

		((tm->tm_mon + 1) & 0xf);



	ctrl = readl(rtc->base + RTC_CTRL);

	writel(ctrl | RTC_UNLOCK, rtc->base + RTC_CTRL);



	writel(reg1, rtc->base + RTC_TIME);

	writel(reg2, rtc->base + RTC_YEAR);



	/* Re-lock and ensure enable is set now that a time is programmed */

	writel(ctrl | RTC_ENABLE, rtc->base + RTC_CTRL);



	return 0;

}



static const struct rtc_class_ops aspeed_rtc_ops = {

	.read_time = aspeed_rtc_read_time,

	.set_time = aspeed_rtc_set_time,

};



static int aspeed_rtc_probe(struct platform_device *pdev)

{

	struct aspeed_rtc *rtc;

	struct resource *res;

	int ret;



	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);

	if (!rtc)

		return -ENOMEM;



	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	rtc->base = devm_ioremap_resource(&pdev->dev, res);

	if (IS_ERR(rtc->base))

		return PTR_ERR(rtc->base);



	rtc->rtc_dev = devm_rtc_allocate_device(&pdev->dev);

	if (IS_ERR(rtc->rtc_dev))

		return PTR_ERR(rtc->rtc_dev);



	platform_set_drvdata(pdev, rtc);



	rtc->rtc_dev->ops = &aspeed_rtc_ops;

	rtc->rtc_dev->range_min = RTC_TIMESTAMP_BEGIN_1900;

	rtc->rtc_dev->range_max = 38814989399LL; /* 3199-12-31 23:59:59 */



	ret = rtc_register_device(rtc->rtc_dev);

	if (ret)

		return ret;



	return 0;

}



static const struct of_device_id aspeed_rtc_match[] = {

	{ .compatible = "aspeed,ast2400-rtc", },

	{ .compatible = "aspeed,ast2500-rtc", },

	{ .compatible = "aspeed,ast2600-rtc", },

	{}

};

MODULE_DEVICE_TABLE(of, aspeed_rtc_match);



static struct platform_driver aspeed_rtc_driver = {

	.driver = {

		.name = "aspeed-rtc",

		.of_match_table = of_match_ptr(aspeed_rtc_match),

	},

};



module_platform_driver_probe(aspeed_rtc_driver, aspeed_rtc_probe);



MODULE_DESCRIPTION("ASPEED RTC driver");

MODULE_AUTHOR("Joel Stanley <joel@jms.id.au>");

MODULE_LICENSE("GPL");