Re: [PATCHv 1/1] RTC:driver for Cortina's SOC

[Alexandre Belloni <alexandre.belloni@free-electrons.com>]

Hi,

On 20/05/2015 at 17:49:31 +0200, Hans Ulli Kroll wrote :
> Driver for the on chip RTC found on Cortina's SoC Gemini.
> 
> Signed-off-by: Hans Ulli Kroll <ulli.kroll@googlemail.com>

I've applied it with a few modifications:
https://git.kernel.org/cgit/linux/kernel/git/abelloni/linux.git/commit/?h=rtc-next&id=a0928c40a908d18f06c05c9db4bdc8e3f0761179

I've removed the need for goto and labels by using devm_request_irq().

> ---
>  MAINTAINERS              |   1 +
>  drivers/rtc/Kconfig      |  11 +++
>  drivers/rtc/Makefile     |   1 +
>  drivers/rtc/rtc-gemini.c | 190 +++++++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 203 insertions(+)
>  create mode 100644 drivers/rtc/rtc-gemini.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index f0d922b..3cff87e 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -977,6 +977,7 @@ L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
>  T:	git git://github.com/ulli-kroll/linux.git
>  S:	Maintained
>  F:	arch/arm/mach-gemini/
> +F:	drivers/rtc/rtc-gemini.c
>  
>  ARM/CSR SIRFPRIMA2 MACHINE SUPPORT
>  M:	Barry Song <baohua@kernel.org>
> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
> index 0fe4ad8..4a37931 100644
> --- a/drivers/rtc/Kconfig
> +++ b/drivers/rtc/Kconfig
> @@ -1372,6 +1372,17 @@ config RTC_DRV_ARMADA38X
>  	  This driver can also be built as a module. If so, the module
>  	  will be called armada38x-rtc.
>  
> +config RTC_DRV_GEMINI
> +	tristate "Gemini SoC RTC"
> +	depends on ARCH_GEMINI || COMPILE_TEST
> +	depends on HAS_IOMEM
> +	help
> +	  If you say Y here you will get support for the
> +	  RTC found on Gemini SoC's.
> +
> +	  This driver can also be built as a module. If so, the module
> +	  will be called rtc-gemini.
> +
>  config RTC_DRV_PS3
>  	tristate "PS3 RTC"
>  	depends on PPC_PS3
> diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
> index 2b82e2b..ed4057a 100644
> --- a/drivers/rtc/Makefile
> +++ b/drivers/rtc/Makefile
> @@ -65,6 +65,7 @@ obj-$(CONFIG_RTC_DRV_EFI)	+= rtc-efi.o
>  obj-$(CONFIG_RTC_DRV_EM3027)	+= rtc-em3027.o
>  obj-$(CONFIG_RTC_DRV_EP93XX)	+= rtc-ep93xx.o
>  obj-$(CONFIG_RTC_DRV_FM3130)	+= rtc-fm3130.o
> +obj-$(CONFIG_RTC_DRV_GEMINI)	+= rtc-gemini.o
>  obj-$(CONFIG_RTC_DRV_GENERIC)	+= rtc-generic.o
>  obj-$(CONFIG_RTC_DRV_HID_SENSOR_TIME) += rtc-hid-sensor-time.o
>  obj-$(CONFIG_RTC_DRV_HYM8563)	+= rtc-hym8563.o
> diff --git a/drivers/rtc/rtc-gemini.c b/drivers/rtc/rtc-gemini.c
> new file mode 100644
> index 0000000..5b36450
> --- /dev/null
> +++ b/drivers/rtc/rtc-gemini.c
> @@ -0,0 +1,190 @@
> +/*
> + *  Gemini OnChip RTC
> + *
> + *  Copyright (C) 2009 Janos Laube <janos.dev@gmail.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.
> + *
> + * Original code for older kernel 2.6.15 are from Stormlinksemi
> + * first update from Janos Laube for > 2.6.29 kernels
> + *
> + * checkpatch fixes and usage of rtc-lib code
> + * Hans Ulli Kroll <ulli.kroll@googlemail.com>
> + */
> +
> +#include <linux/rtc.h>
> +#include <linux/io.h>
> +#include <linux/slab.h>
> +#include <linux/platform_device.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +
> +#define DRV_NAME        "rtc-gemini"
> +#define DRV_VERSION     "0.2"
> +
> +MODULE_AUTHOR("Hans Ulli Kroll <ulli.kroll@googlemail.com>");
> +MODULE_DESCRIPTION("RTC driver for Gemini SoC");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:" DRV_NAME);
> +
> +struct gemini_rtc {
> +	struct rtc_device	*rtc_dev;
> +	void __iomem		*rtc_base;
> +	int			rtc_irq;
> +};
> +
> +enum gemini_rtc_offsets {
> +	GEMINI_RTC_SECOND	= 0x00,
> +	GEMINI_RTC_MINUTE	= 0x04,
> +	GEMINI_RTC_HOUR		= 0x08,
> +	GEMINI_RTC_DAYS		= 0x0C,
> +	GEMINI_RTC_ALARM_SECOND	= 0x10,
> +	GEMINI_RTC_ALARM_MINUTE	= 0x14,
> +	GEMINI_RTC_ALARM_HOUR	= 0x18,
> +	GEMINI_RTC_RECORD	= 0x1C,
> +	GEMINI_RTC_CR		= 0x20
> +};
> +
> +static irqreturn_t gemini_rtc_interrupt(int irq, void *dev)
> +{
> +	return IRQ_HANDLED;
> +}
> +
> +/*
> + * Looks like the RTC in the Gemini SoC is (totaly) broken
> + * We can't read/write directly the time from RTC registers.
> + * We must do some "offset" calculation to get the real time
> + *
> + * This FIX works pretty fine and Stormlinksemi aka Cortina-Networks does
> + * the same thing, without the rtc-lib.c calls.
> + */
> +
> +static int gemini_rtc_read_time(struct device *dev, struct rtc_time *tm)
> +{
> +	struct gemini_rtc *rtc = dev_get_drvdata(dev);
> +
> +	unsigned int  days, hour, min, sec;
> +	unsigned long offset, time;
> +
> +	sec  = readl(rtc->rtc_base + GEMINI_RTC_SECOND);
> +	min  = readl(rtc->rtc_base + GEMINI_RTC_MINUTE);
> +	hour = readl(rtc->rtc_base + GEMINI_RTC_HOUR);
> +	days = readl(rtc->rtc_base + GEMINI_RTC_DAYS);
> +	offset = readl(rtc->rtc_base + GEMINI_RTC_RECORD);
> +
> +	time = offset + days * 86400 + hour * 3600 + min * 60 + sec;
> +
> +	rtc_time_to_tm(time, tm);
> +
> +	return 0;
> +}
> +
> +static int gemini_rtc_set_time(struct device *dev, struct rtc_time *tm)
> +{
> +	struct gemini_rtc *rtc = dev_get_drvdata(dev);
> +	unsigned int sec, min, hour, day;
> +	unsigned long offset, time;
> +
> +	if (tm->tm_year >= 2148)	/* EPOCH Year + 179 */
> +		return -EINVAL;
> +
> +	rtc_tm_to_time(tm, &time);
> +
> +	sec = readl(rtc->rtc_base + GEMINI_RTC_SECOND);
> +	min = readl(rtc->rtc_base + GEMINI_RTC_MINUTE);
> +	hour = readl(rtc->rtc_base + GEMINI_RTC_HOUR);
> +	day = readl(rtc->rtc_base + GEMINI_RTC_DAYS);
> +
> +	offset = time - (day * 86400 + hour * 3600 + min * 60 + sec);
> +
> +	writel(offset, rtc->rtc_base + GEMINI_RTC_RECORD);
> +	writel(0x01, rtc->rtc_base + GEMINI_RTC_CR);
> +
> +	return 0;
> +}
> +
> +static struct rtc_class_ops gemini_rtc_ops = {
> +	.read_time     = gemini_rtc_read_time,
> +	.set_time      = gemini_rtc_set_time,
> +};
> +
> +static int gemini_rtc_probe(struct platform_device *pdev)
> +{
> +	struct gemini_rtc *rtc;
> +	struct device *dev = &pdev->dev;
> +	struct resource *res;
> +	int ret;
> +
> +	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
> +	if (unlikely(!rtc))
> +		return -ENOMEM;
> +	platform_set_drvdata(pdev, rtc);
> +
> +	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
> +	if (!res) {
> +		ret = -ENODEV;
> +		goto err_mem;
> +	}
> +	rtc->rtc_irq = res->start;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (!res) {
> +		ret = -ENODEV;
> +		goto err_mem;
> +	}
> +	rtc->rtc_base =	devm_ioremap(&pdev->dev, res->start,
> +				    res->end - res->start + 1);
> +
> +	ret = request_irq(rtc->rtc_irq, gemini_rtc_interrupt,
> +			 IRQF_SHARED, pdev->name, dev);
> +	if (unlikely(ret))
> +		goto err_mem;
> +
> +	rtc->rtc_dev =	rtc_device_register(pdev->name, dev,
> +					   &gemini_rtc_ops, THIS_MODULE);
> +	if (likely(IS_ERR(rtc->rtc_dev))) {
> +		ret = PTR_ERR(rtc->rtc_dev);
> +		goto err_irq;
> +	}
> +	return 0;
> +
> +err_irq:
> +	free_irq(rtc->rtc_irq, dev);
> +
> +err_mem:
> +	kfree(rtc);
> +	return ret;
> +}
> +
> +static int gemini_rtc_remove(struct platform_device *pdev)
> +{
> +	struct gemini_rtc *rtc = platform_get_drvdata(pdev);
> +	struct device *dev = &pdev->dev;
> +
> +	free_irq(rtc->rtc_irq, dev);
> +	rtc_device_unregister(rtc->rtc_dev);
> +	platform_set_drvdata(pdev, NULL);
> +	kfree(rtc);
> +
> +	return 0;
> +}
> +
> +static struct platform_driver gemini_rtc_driver = {
> +	.driver		= {
> +		.name	= DRV_NAME,
> +		.owner	= THIS_MODULE,
> +	},
> +	.probe		= gemini_rtc_probe,
> +	.remove		= gemini_rtc_remove,
> +};
> +
> +module_platform_driver_probe(gemini_rtc_driver, gemini_rtc_probe);
> +
> -- 
> 2.4.0
> 

-- 
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com