[rtc-linux] [PATCH 2/3] rtc: Add APM X-Gene SoC RTC driver

[a.zummo@towertech.it (Alessandro Zummo)]

On Fri, 28 Mar 2014 14:56:37 -0600
Loc Ho <lho@apm.com> wrote:

 Hello, a few notes below:

> ---
>  drivers/rtc/Kconfig     |    9 ++
>  drivers/rtc/Makefile    |    1 +
>  drivers/rtc/rtc-xgene.c |  278 +++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 288 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/rtc/rtc-xgene.c
> 
> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
> index db933de..4e3a683 100644
> --- a/drivers/rtc/Kconfig
> +++ b/drivers/rtc/Kconfig
> @@ -1315,6 +1315,15 @@ config RTC_DRV_MOXART
>  	   This driver can also be built as a module. If so, the module
>  	   will be called rtc-moxart
>  
> +config RTC_DRV_XGENE
> +	tristate "APM X-Gene RTC"
> +	help
> +	  If you say yes here you get support for the APM X-Gene SoC real time
> +	  clock.
> +
> +	  This driver can also be built as a module, if so, the module
> +	  will be called "rtc-xgene".
> +
>  comment "HID Sensor RTC drivers"
>  
>  config RTC_DRV_HID_SENSOR_TIME
> diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
> index b427bf7..ceccd46 100644
> --- a/drivers/rtc/Makefile
> +++ b/drivers/rtc/Makefile
> @@ -134,5 +134,6 @@ obj-$(CONFIG_RTC_DRV_VT8500)	+= rtc-vt8500.o
>  obj-$(CONFIG_RTC_DRV_WM831X)	+= rtc-wm831x.o
>  obj-$(CONFIG_RTC_DRV_WM8350)	+= rtc-wm8350.o
>  obj-$(CONFIG_RTC_DRV_X1205)	+= rtc-x1205.o
> +obj-$(CONFIG_RTC_DRV_XGENE)	+= rtc-xgene.o
>  obj-$(CONFIG_RTC_DRV_SIRFSOC)	+= rtc-sirfsoc.o
>  obj-$(CONFIG_RTC_DRV_MOXART)	+= rtc-moxart.o
> diff --git a/drivers/rtc/rtc-xgene.c b/drivers/rtc/rtc-xgene.c
> new file mode 100644
> index 0000000..61223a5
> --- /dev/null
> +++ b/drivers/rtc/rtc-xgene.c
> @@ -0,0 +1,278 @@
> +/*
> + * APM X-Gene SoC Real Time Clock Driver
> + *
> + * Copyright (c) 2014, Applied Micro Circuits Corporation
> + * Author: Rameshwar Prasad Sahu <rsahu@apm.com>
> + *         Loc Ho <lho@apm.com>
> + *
> + * This program is free software; you can redistribute  it and/or modify it
> + * under  the terms of  the GNU General  Public License as published by the
> + * Free Software Foundation;  either version 2 of the  License, or (at your
> + * option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
> + *
> + */
> +
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/io.h>
> +#include <linux/slab.h>
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/rtc.h>
> +
> +/* RTC CSR Registers */
> +#define RTC_CCVR		0x00
> +#define RTC_CMR			0x04
> +#define RTC_CLR			0x08
> +#define RTC_CCR			0x0C
> +#define  RTC_CCR_IE		BIT(0)
> +#define  RTC_CCR_MASK		BIT(1)
> +#define  RTC_CCR_EN		BIT(2)
> +#define  RTC_CCR_WEN		BIT(3)
> +#define RTC_STAT		0x10
> +#define  RTC_STAT_BIT		BIT(0)
> +#define RTC_RSTAT		0x14
> +#define RTC_EOI			0x18
> +#define RTC_VER			0x1C
> +
> +struct xgene_rtc_dev {
> +	struct rtc_device *rtc;
> +	struct device *dev;
> +	unsigned long alarm_time;
> +	void __iomem *csr_base;
> +	struct clk *clk;
> +	unsigned int irq_wake;
> +};
> +
> +static int xgene_rtc_read_time(struct device *dev, struct rtc_time *tm)
> +{
> +	struct xgene_rtc_dev *pdata = dev_get_drvdata(dev);
> +
> +	rtc_time_to_tm(readl(pdata->csr_base + RTC_CCVR), tm);
> +	return 0;
> +}

  return rtc_valid_tm(tm);


> +
> +static int xgene_rtc_set_mmss(struct device *dev, unsigned long secs)
> +{
> +	struct xgene_rtc_dev *pdata = dev_get_drvdata(dev);
> +
> +	/*
> +	 * NOTE: After the following write, the RTC_CCVR is only reflected
> +	 *       after the update cycle of 1 seconds.
> +	 */
> +	writel((u32) secs, pdata->csr_base + RTC_CLR);
> +	readl(pdata->csr_base + RTC_CLR); /* Force a barrier */
> +
> +	return 0;
> +}
> +
> +static int xgene_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
> +{
> +	struct xgene_rtc_dev *pdata = dev_get_drvdata(dev);
> +
> +	rtc_time_to_tm(pdata->alarm_time, &alrm->time);
> +	alrm->enabled = readl(pdata->csr_base + RTC_CCR) & RTC_CCR_IE;
> +
> +	return 0;
> +}
> +
> +static int xgene_rtc_alarm_irq_enable(struct device *dev, u32 enabled)
> +{
> +	struct xgene_rtc_dev *pdata = dev_get_drvdata(dev);
> +	u32 ccr;
> +
> +	ccr = readl(pdata->csr_base + RTC_CCR);
> +	if (enabled) {
> +		ccr &= ~RTC_CCR_MASK;
> +		ccr |= RTC_CCR_IE;
> +	} else {
> +		ccr &= ~RTC_CCR_IE;
> +		ccr |= RTC_CCR_MASK;
> +	}
> +	writel(ccr, pdata->csr_base + RTC_CCR);
> +
> +	return 0;
> +}
> +
> +static int xgene_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
> +{
> +	struct xgene_rtc_dev *pdata = dev_get_drvdata(dev);
> +	unsigned long rtc_time;
> +	unsigned long alarm_time;
> +
> +	rtc_time = readl(pdata->csr_base + RTC_CCVR);
> +	rtc_tm_to_time(&alrm->time, &alarm_time);
> +
> +	pdata->alarm_time = alarm_time;
> +	writel((u32) pdata->alarm_time, pdata->csr_base + RTC_CMR);
> +
> +	xgene_rtc_alarm_irq_enable(dev, alrm->enabled);
> +
> +	return 0;
> +}
> +
> +static const struct rtc_class_ops xgene_rtc_ops = {
> +	.read_time	= xgene_rtc_read_time,
> +	.set_mmss	= xgene_rtc_set_mmss,
> +	.read_alarm	= xgene_rtc_read_alarm,
> +	.set_alarm	= xgene_rtc_set_alarm,
> +	.alarm_irq_enable = xgene_rtc_alarm_irq_enable,
> +};
> +
> +static irqreturn_t xgene_rtc_interrupt(int irq, void *id)
> +{
> +	struct xgene_rtc_dev *pdata = (struct xgene_rtc_dev *) id;
> +
> +	/* Check if interrupt asserted */
> +	if (!(readl(pdata->csr_base + RTC_STAT) & RTC_STAT_BIT))
> +		return IRQ_NONE;
> +
> +	/* Clear interrupt */
> +	readl(pdata->csr_base + RTC_EOI);
> +
> +	rtc_update_irq(pdata->rtc, 1, RTC_IRQF | RTC_AF);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int xgene_rtc_probe(struct platform_device *pdev)
> +{
> +	struct xgene_rtc_dev *pdata;
> +	struct resource *res;
> +	int ret;
> +	int irq;
> +
> +	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
> +	if (!pdata)
> +		return -ENOMEM;
> +	platform_set_drvdata(pdev, pdata);
> +	pdata->dev = &pdev->dev;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	pdata->csr_base = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(pdata->csr_base))
> +		return PTR_ERR(pdata->csr_base);
> +
> +	irq = platform_get_irq(pdev, 0);
> +	if (irq < 0) {
> +		dev_err(&pdev->dev, "No IRQ resource\n");
> +		return irq;
> +	}
> +	ret = devm_request_irq(&pdev->dev, irq, xgene_rtc_interrupt, 0,
> +			       dev_name(&pdev->dev), pdata);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Could not request IRQ\n");
> +		return ret;
> +	}
> +
> +	pdata->clk = devm_clk_get(&pdev->dev, NULL);
> +	if (IS_ERR(pdata->clk)) {
> +		dev_err(&pdev->dev, "Couldn't get the clock for RTC\n");
> +		return -ENODEV;
> +	}
> +	clk_prepare_enable(pdata->clk);
> +
> +	/* Turn on the clock and the crystal */
> +	writel(RTC_CCR_EN, pdata->csr_base + RTC_CCR);
> +
> +	device_init_wakeup(&pdev->dev, 1);
> +
> +	pdata->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
> +					 &xgene_rtc_ops, THIS_MODULE);
> +	if (IS_ERR(pdata->rtc)) {
> +		clk_disable_unprepare(pdata->clk);
> +		return PTR_ERR(pdata->rtc);
> +	}
> +
> +	/* HW does not support update faster than 1 seconds */
> +	pdata->rtc->uie_unsupported = 1;
> +
> +	return 0;
> +}
> +
> +static int xgene_rtc_remove(struct platform_device *pdev)
> +{
> +	struct xgene_rtc_dev *pdata = platform_get_drvdata(pdev);
> +
> +	xgene_rtc_alarm_irq_enable(&pdev->dev, 0);
> +	device_init_wakeup(&pdev->dev, 0);
> +	clk_disable_unprepare(pdata->clk);
> +	return 0;
> +}
> +
> +#ifdef CONFIG_PM_SLEEP
> +static int xgene_rtc_suspend(struct device *dev)
> +{
> +	struct platform_device *pdev = to_platform_device(dev);
> +	struct xgene_rtc_dev *pdata = platform_get_drvdata(pdev);
> +	int irq;
> +
> +	irq = platform_get_irq(pdev, 0);
> +	if (device_may_wakeup(&pdev->dev)) {
> +		if (!enable_irq_wake(irq))
> +			pdata->irq_wake = 1;
> +	} else {
> +		xgene_rtc_alarm_irq_enable(dev, 0);
> +		clk_disable(pdata->clk);
> +	}
> +
> +	return 0;
> +}
> +
> +static int xgene_rtc_resume(struct device *dev)
> +{
> +	struct platform_device *pdev = to_platform_device(dev);
> +	struct xgene_rtc_dev *pdata = platform_get_drvdata(pdev);
> +	int irq;
> +
> +	irq = platform_get_irq(pdev, 0);
> +	if (device_may_wakeup(&pdev->dev)) {
> +		if (pdata->irq_wake) {
> +			disable_irq_wake(irq);
> +			pdata->irq_wake = 0;
> +		}
> +	} else {
> +		clk_enable(pdata->clk);
> +		xgene_rtc_alarm_irq_enable(dev, 1);
> +	}
> +
> +	return 0;
> +}
> +#endif
> +
> +static SIMPLE_DEV_PM_OPS(xgene_rtc_pm_ops, xgene_rtc_suspend, xgene_rtc_resume);
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id xgene_rtc_of_match[] = {
> +	{.compatible = "apm,xgene-rtc" },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, xgene_rtc_of_match);
> +#endif
> +
> +static struct platform_driver xgene_rtc_driver = {
> +	.probe		= xgene_rtc_probe,
> +	.remove		= xgene_rtc_remove,
> +	.driver		= {
> +		.owner	= THIS_MODULE,
> +		.name	= "xgene-rtc",
> +		.pm = &xgene_rtc_pm_ops,
> +		.of_match_table	= of_match_ptr(xgene_rtc_of_match),
> +	},
> +};
> +
> +module_platform_driver(xgene_rtc_driver);
> +
> +MODULE_DESCRIPTION("APM X-Gene SoC RTC driver");
> +MODULE_AUTHOR("Rameshwar Sahu <rsahu@apm.com>");
> +MODULE_LICENSE("GPL");
> -- 
> 1.5.5
> 
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-- 

 Best regards,

 Alessandro Zummo,
  Tower Technologies - Torino, Italy

  http://www.towertech.it