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Re: [PATCH v2] M48T35: new RTC driver

To: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Subject: Re: [PATCH v2] M48T35: new RTC driver
From: Alessandro Zummo <alessandro.zummo@towertech.it>
Date: Thu, 7 Aug 2008 10:55:55 +0200
Cc: rtc-linux@googlegroups.com, linux-mips@linux-mips.org, ralf@linux-mips.org
In-reply-to: <20080804170025.CBA97C2EAC@solo.franken.de>
Organization: Tower Technologies
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <20080804170025.CBA97C2EAC@solo.franken.de>
Sender: linux-mips-bounce@linux-mips.org
On Mon,  4 Aug 2008 19:00:25 +0200 (CEST)
Thomas Bogendoerfer <tsbogend@alpha.franken.de> wrote:

 seems ok, please fix that one liner and you can
 send it to andrew with my 

  Acked-by: Alessandro Zummo <a.zummo@towertech.it>

 thanks!


> This driver replaces the broken ip27-rtc driver in drivers/char and
> gives back RTC support for SGI IP27 machines.
> 
> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
> ---
> 
> Changes in v2:
> 
> - don't depend on SGI_IP27
> - use rtc_valid_tm() for tm validation
> - resource is now a physical address and is ioremapped now
> - added kludge to workaround current ioc3 resource conflict
> 
>  drivers/rtc/Kconfig      |    9 ++
>  drivers/rtc/Makefile     |    1 +
>  drivers/rtc/rtc-m48t35.c |  237 
> ++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 247 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
> index 90ab738..2e5a578 100644
> --- a/drivers/rtc/Kconfig
> +++ b/drivers/rtc/Kconfig
> @@ -405,6 +405,15 @@ config RTC_DRV_M48T86
>         This driver can also be built as a module. If so, the module
>         will be called rtc-m48t86.
>  
> +config RTC_DRV_M48T35
> +     tristate "ST M48T35"
> +     help
> +       If you say Y here you will get support for the
> +       ST M48T35 RTC chip.
> +
> +       This driver can also be built as a module, if so, the module
> +       will be called "rtc-m48t35".
> +
>  config RTC_DRV_M48T59
>       tristate "ST M48T59"
>       help
> diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
> index 18622ef..7d10cc0 100644
> --- a/drivers/rtc/Makefile
> +++ b/drivers/rtc/Makefile
> @@ -36,6 +36,7 @@ obj-$(CONFIG_RTC_DRV_FM3130)        += rtc-fm3130.o
>  obj-$(CONFIG_RTC_DRV_ISL1208)        += rtc-isl1208.o
>  obj-$(CONFIG_RTC_DRV_M41T80) += rtc-m41t80.o
>  obj-$(CONFIG_RTC_DRV_M41T94) += rtc-m41t94.o
> +obj-$(CONFIG_RTC_DRV_M48T35) += rtc-m48t35.o
>  obj-$(CONFIG_RTC_DRV_M48T59) += rtc-m48t59.o
>  obj-$(CONFIG_RTC_DRV_M48T86) += rtc-m48t86.o
>  obj-$(CONFIG_RTC_DRV_MAX6900)        += rtc-max6900.o
> diff --git a/drivers/rtc/rtc-m48t35.c b/drivers/rtc/rtc-m48t35.c
> new file mode 100644
> index 0000000..e618b9a
> --- /dev/null
> +++ b/drivers/rtc/rtc-m48t35.c
> @@ -0,0 +1,237 @@
> +/*
> + * Driver for the SGS-Thomson M48T35 Timekeeper RAM chip
> + *
> + * Copyright (C) 2000 Silicon Graphics, Inc.
> + * Written by Ulf Carlsson (ulfc@engr.sgi.com)
> + *
> + * Copyright (C) 2008 Thomas Bogendoerfer
> + *
> + * Based on code written by Paul Gortmaker.
> + *
> + * 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.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/rtc.h>
> +#include <linux/platform_device.h>
> +#include <linux/bcd.h>
> +
> +#define DRV_VERSION          "1.0"
> +
> +struct m48t35_rtc {
> +     u8      pad[0x7ff8];    /* starts at 0x7ff8 */
> +     u8      control;
> +     u8      sec;
> +     u8      min;
> +     u8      hour;
> +     u8      day;
> +     u8      date;
> +     u8      month;
> +     u8      year;
> +};
> +
> +#define M48T35_RTC_SET               0x80
> +#define M48T35_RTC_READ              0x40
> +
> +struct m48t35_priv {
> +     struct rtc_device *rtc;
> +     struct m48t35_rtc __iomem *reg;
> +     size_t size;
> +     unsigned long baseaddr;
> +     spinlock_t lock;
> +};
> +
> +static int m48t35_read_time(struct device *dev, struct rtc_time *tm)
> +{
> +     struct m48t35_priv *priv = dev_get_drvdata(dev);
> +     u8 control;
> +
> +     /*
> +      * Only the values that we read from the RTC are set. We leave
> +      * tm_wday, tm_yday and tm_isdst untouched. Even though the
> +      * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
> +      * by the RTC when initially set to a non-zero value.
> +      */
> +     spin_lock_irq(&priv->lock);
> +     control = readb(&priv->reg->control);
> +     writeb(control | M48T35_RTC_READ, &priv->reg->control);
> +     tm->tm_sec = readb(&priv->reg->sec);
> +     tm->tm_min = readb(&priv->reg->min);
> +     tm->tm_hour = readb(&priv->reg->hour);
> +     tm->tm_mday = readb(&priv->reg->date);
> +     tm->tm_mon = readb(&priv->reg->month);
> +     tm->tm_year = readb(&priv->reg->year);
> +     writeb(control, &priv->reg->control);
> +     spin_unlock_irq(&priv->lock);
> +
> +     tm->tm_sec = BCD2BIN(tm->tm_sec);
> +     tm->tm_min = BCD2BIN(tm->tm_min);
> +     tm->tm_hour = BCD2BIN(tm->tm_hour);
> +     tm->tm_mday = BCD2BIN(tm->tm_mday);
> +     tm->tm_mon = BCD2BIN(tm->tm_mon);
> +     tm->tm_year = BCD2BIN(tm->tm_year);
> +
> +     /*
> +      * Account for differences between how the RTC uses the values
> +      * and how they are defined in a struct rtc_time;
> +      */
> +     tm->tm_year += 70;
> +     if (tm->tm_year <= 69)
> +             tm->tm_year += 100;
> +
> +     tm->tm_mon--;
> +     return rtc_valid_tm(tm);
> +}
> +
> +static int m48t35_set_time(struct device *dev, struct rtc_time *tm)
> +{
> +     struct m48t35_priv *priv = dev_get_drvdata(dev);
> +     unsigned char mon, day, hrs, min, sec;
> +     unsigned int yrs;
> +     u8 control;
> +
> +     yrs = tm->tm_year + 1900;
> +     mon = tm->tm_mon + 1;   /* tm_mon starts at zero */
> +     day = tm->tm_mday;
> +     hrs = tm->tm_hour;
> +     min = tm->tm_min;
> +     sec = tm->tm_sec;
> +
> +     if (!rtc_valid_tm(tm))
> +             return -EINVAL;
> +
> +     if (yrs < 1970)
> +             return -EINVAL;
> +
> +     yrs -= 1970;
> +     if (yrs > 255)    /* They are unsigned */
> +             return -EINVAL;
> +
> +     if (yrs > 169)
> +             return -EINVAL;
> +
> +     if (yrs >= 100)
> +             yrs -= 100;
> +
> +     sec = BIN2BCD(sec);
> +     min = BIN2BCD(min);
> +     hrs = BIN2BCD(hrs);
> +     day = BIN2BCD(day);
> +     mon = BIN2BCD(mon);
> +     yrs = BIN2BCD(yrs);
> +
> +     spin_lock_irq(&priv->lock);
> +     control = readb(&priv->reg->control);
> +     writeb(control | M48T35_RTC_SET, &priv->reg->control);
> +     writeb(yrs, &priv->reg->year);
> +     writeb(mon, &priv->reg->month);
> +     writeb(day, &priv->reg->date);
> +     writeb(hrs, &priv->reg->hour);
> +     writeb(min, &priv->reg->min);
> +     writeb(sec, &priv->reg->sec);
> +     writeb(control, &priv->reg->control);
> +     spin_unlock_irq(&priv->lock);
> +     return 0;
> +}
> +
> +static const struct rtc_class_ops m48t35_ops = {
> +     .read_time      = m48t35_read_time,
> +     .set_time       = m48t35_set_time,
> +};
> +
> +static int __devinit m48t35_probe(struct platform_device *pdev)
> +{
> +     struct rtc_device *rtc;
> +     struct resource *res;
> +     struct m48t35_priv *priv;
> +     int ret = 0;
> +
> +     res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +     if (!res)
> +             return -ENODEV;
> +     priv = kzalloc(sizeof *priv, GFP_KERNEL);

 same as the other patch :)

> +     if (!priv)
> +             return -ENOMEM;
> +
> +     priv->size = res->end - res->start + 1;
> +     /*
> +      * kludge: remove the #ifndef after ioc3 resource
> +      * conflicts are resolved
> +      */
> +#ifndef CONFIG_SGI_IP27
> +     if (!request_mem_region(res->start, priv->size, pdev->name)) {
> +             ret = -EBUSY;
> +             goto out;
> +     }
> +#endif
> +     priv->baseaddr = res->start;
> +     priv->reg = ioremap(priv->baseaddr, priv->size);
> +     if (!priv->reg) {
> +             ret = -ENOMEM;
> +             goto out;
> +     }
> +     spin_lock_init(&priv->lock);
> +     rtc = rtc_device_register("m48t35", &pdev->dev,
> +                               &m48t35_ops, THIS_MODULE);
> +     if (IS_ERR(rtc)) {
> +             ret = PTR_ERR(rtc);
> +             goto out;
> +     }
> +     priv->rtc = rtc;
> +     platform_set_drvdata(pdev, priv);
> +     return 0;
> +
> +out:
> +     if (priv->rtc)
> +             rtc_device_unregister(priv->rtc);
> +     if (priv->reg)
> +             iounmap(priv->reg);
> +     if (priv->baseaddr)
> +             release_mem_region(priv->baseaddr, priv->size);
> +     kfree(priv);
> +     return ret;
> +}
> +
> +static int __devexit m48t35_remove(struct platform_device *pdev)
> +{
> +     struct m48t35_priv *priv = platform_get_drvdata(pdev);
> +
> +     rtc_device_unregister(priv->rtc);
> +     iounmap(priv->reg);
> +#ifndef CONFIG_SGI_IP27
> +     release_mem_region(priv->baseaddr, priv->size);
> +#endif
> +     kfree(priv);
> +     return 0;
> +}
> +
> +static struct platform_driver m48t35_platform_driver = {
> +     .driver         = {
> +             .name   = "rtc-m48t35",
> +             .owner  = THIS_MODULE,
> +     },
> +     .probe          = m48t35_probe,
> +     .remove         = __devexit_p(m48t35_remove),
> +};
> +
> +static int __init m48t35_init(void)
> +{
> +     return platform_driver_register(&m48t35_platform_driver);
> +}
> +
> +static void __exit m48t35_exit(void)
> +{
> +     platform_driver_unregister(&m48t35_platform_driver);
> +}
> +
> +MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>");
> +MODULE_DESCRIPTION("M48T35 RTC driver");
> +MODULE_LICENSE("GPL");
> +MODULE_VERSION(DRV_VERSION);
> +MODULE_ALIAS("platform:rtc-m48t35");
> +
> +module_init(m48t35_init);
> +module_exit(m48t35_exit);


-- 

 Best regards,

 Alessandro Zummo,
  Tower Technologies - Torino, Italy

  http://www.towertech.it


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