Patchwork rtc: rp5c01 - Add NVRAM support

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Submitter Geert Uytterhoeven
Date June 13, 2010, 10:12 a.m.
Message ID <alpine.DEB.2.00.1006131208470.18415@ayla.of.borg>
Download mbox | patch
Permalink /patch/55414/
State New
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Geert Uytterhoeven - June 13, 2010, 10:12 a.m.
The Ricoh RP5C01 RTC contains 26 x 4 bits of NVRAM.
Provide access to it via a sysfs "nvram" attribute file.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
--
Question: Is a spinlock in priv the right kind of locking?
	  Should I use e.g. rtc-device.ops_lock instead?
Wan ZongShun - June 13, 2010, 1:41 p.m.
Hi Geert ,

Minior comment below:

2010/6/13 Geert Uytterhoeven <geert@linux-m68k.org>:
> The Ricoh RP5C01 RTC contains 26 x 4 bits of NVRAM.
> Provide access to it via a sysfs "nvram" attribute file.
>
> Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
> --
> Question: Is a spinlock in priv the right kind of locking?
>          Should I use e.g. rtc-device.ops_lock instead?

Firstly, this 'Question' text should not put here, please put all
texts in front of '---'.
Secondly, You can not use rtc-device.ops_lock here, if so, it would
arouse dead lock,
before the ' rp5c01_read_time()' was called by RTC subsystem upper
API, rtc-device.ops_lock
has been required sucessfully, If continue to require the
rtc-device.ops_lock in ' rp5c01_read_time()',
the 'lock' will cannot be get, dead lock occurs.

>
> diff --git a/drivers/rtc/rtc-rp5c01.c b/drivers/rtc/rtc-rp5c01.c
> index a95f733..36eb661 100644
> --- a/drivers/rtc/rtc-rp5c01.c
> +++ b/drivers/rtc/rtc-rp5c01.c
> @@ -63,6 +63,8 @@ enum {
>  struct rp5c01_priv {
>        u32 __iomem *regs;
>        struct rtc_device *rtc;
> +       spinlock_t lock;        /* against concurrent RTC/NVRAM access */
> +       struct bin_attribute nvram_attr;
>  };
>
>  static inline unsigned int rp5c01_read(struct rp5c01_priv *priv,
> @@ -92,6 +94,7 @@ static int rp5c01_read_time(struct device *dev, struct rtc_time *tm)
>  {
>        struct rp5c01_priv *priv = dev_get_drvdata(dev);
>
> +       spin_lock_irq(&priv->lock);
>        rp5c01_lock(priv);
>
>        tm->tm_sec  = rp5c01_read(priv, RP5C01_10_SECOND) * 10 +
> @@ -111,6 +114,7 @@ static int rp5c01_read_time(struct device *dev, struct rtc_time *tm)
>                tm->tm_year += 100;
>
>        rp5c01_unlock(priv);
> +       spin_unlock_irq(&priv->lock);
>
>        return rtc_valid_tm(tm);
>  }
> @@ -119,6 +123,7 @@ static int rp5c01_set_time(struct device *dev, struct rtc_time *tm)
>  {
>        struct rp5c01_priv *priv = dev_get_drvdata(dev);
>
> +       spin_lock_irq(&priv->lock);
>        rp5c01_lock(priv);
>
>        rp5c01_write(priv, tm->tm_sec / 10, RP5C01_10_SECOND);
> @@ -139,6 +144,7 @@ static int rp5c01_set_time(struct device *dev, struct rtc_time *tm)
>        rp5c01_write(priv, tm->tm_year % 10, RP5C01_1_YEAR);
>
>        rp5c01_unlock(priv);
> +       spin_unlock_irq(&priv->lock);
>        return 0;
>  }
>
> @@ -147,6 +153,72 @@ static const struct rtc_class_ops rp5c01_rtc_ops = {
>        .set_time       = rp5c01_set_time,
>  };
>
> +
> +/*
> + * The NVRAM is organized as 2 blocks of 13 nibbles of 4 bits.
> + * We provide access to them like AmigaOS does: the high nibble of each 8-bit
> + * byte is stored in BLOCK10, the low nibble in BLOCK11.
> + */
> +
> +static ssize_t rp5c01_nvram_read(struct file *filp, struct kobject *kobj,
> +                                struct bin_attribute *bin_attr,
> +                                char *buf, loff_t pos, size_t size)
> +{
> +       struct device *dev = container_of(kobj, struct device, kobj);
> +       struct rp5c01_priv *priv = dev_get_drvdata(dev);
> +       ssize_t count;
> +
> +       spin_lock_irq(&priv->lock);
> +
> +       for (count = 0; size > 0 && pos < RP5C01_MODE; count++, size--) {
> +               u8 data;
> +
> +               rp5c01_write(priv,
> +                            RP5C01_MODE_TIMER_EN | RP5C01_MODE_RAM_BLOCK10,
> +                            RP5C01_MODE);
> +               data = rp5c01_read(priv, pos) << 4;
> +               rp5c01_write(priv,
> +                            RP5C01_MODE_TIMER_EN | RP5C01_MODE_RAM_BLOCK11,
> +                            RP5C01_MODE);
> +               data |= rp5c01_read(priv, pos++);
> +               rp5c01_write(priv, RP5C01_MODE_TIMER_EN | RP5C01_MODE_MODE01,
> +                            RP5C01_MODE);
> +               *buf++ = data;
> +       }
> +
> +       spin_unlock_irq(&priv->lock);
> +       return count;
> +}
> +
> +static ssize_t rp5c01_nvram_write(struct file *filp, struct kobject *kobj,
> +                                 struct bin_attribute *bin_attr,
> +                                 char *buf, loff_t pos, size_t size)
> +{
> +       struct device *dev = container_of(kobj, struct device, kobj);
> +       struct rp5c01_priv *priv = dev_get_drvdata(dev);
> +       ssize_t count;
> +
> +       spin_lock_irq(&priv->lock);
> +
> +       for (count = 0; size > 0 && pos < RP5C01_MODE; count++, size--) {
> +               u8 data = *buf++;
> +
> +               rp5c01_write(priv,
> +                            RP5C01_MODE_TIMER_EN | RP5C01_MODE_RAM_BLOCK10,
> +                            RP5C01_MODE);
> +               rp5c01_write(priv, data >> 4, pos);
> +               rp5c01_write(priv,
> +                            RP5C01_MODE_TIMER_EN | RP5C01_MODE_RAM_BLOCK11,
> +                            RP5C01_MODE);
> +               rp5c01_write(priv, data & 0xf, pos++);
> +               rp5c01_write(priv, RP5C01_MODE_TIMER_EN | RP5C01_MODE_MODE01,
> +                            RP5C01_MODE);
> +       }
> +
> +       spin_unlock_irq(&priv->lock);
> +       return count;
> +}
> +
>  static int __init rp5c01_rtc_probe(struct platform_device *dev)
>  {
>        struct resource *res;
> @@ -168,6 +240,15 @@ static int __init rp5c01_rtc_probe(struct platform_device *dev)
>                goto out_free_priv;
>        }
>
> +       sysfs_bin_attr_init(&priv->nvram_attr);
> +       priv->nvram_attr.attr.name = "nvram";
> +       priv->nvram_attr.attr.mode = S_IRUGO | S_IWUSR;
> +       priv->nvram_attr.read = rp5c01_nvram_read;
> +       priv->nvram_attr.write = rp5c01_nvram_write;
> +       priv->nvram_attr.size = RP5C01_MODE;
> +
> +       spin_lock_init(&priv->lock);
> +
>        rtc = rtc_device_register("rtc-rp5c01", &dev->dev, &rp5c01_rtc_ops,
>                                  THIS_MODULE);
>        if (IS_ERR(rtc)) {
> @@ -177,8 +258,15 @@ static int __init rp5c01_rtc_probe(struct platform_device *dev)
>
>        priv->rtc = rtc;
>        platform_set_drvdata(dev, priv);
> +
> +       error = sysfs_create_bin_file(&dev->dev.kobj, &priv->nvram_attr);
> +       if (error)
> +               goto out_unregister;
> +
>        return 0;
>
> +out_unregister:
> +       rtc_device_unregister(rtc);
>  out_unmap:
>        iounmap(priv->regs);
>  out_free_priv:
> @@ -190,6 +278,7 @@ static int __exit rp5c01_rtc_remove(struct platform_device *dev)
>  {
>        struct rp5c01_priv *priv = platform_get_drvdata(dev);
>
> +       sysfs_remove_bin_file(&dev->dev.kobj, &priv->nvram_attr);
>        rtc_device_unregister(priv->rtc);
>        iounmap(priv->regs);
>        kfree(priv);
> --
> 1.7.0.4
>
> Gr{oetje,eeting}s,
>
>                                                Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                                            -- Linus Torvalds
>
> --
> You received this message because you are subscribed to "rtc-linux".
> Membership options at http://groups.google.com/group/rtc-linux .
> Please read http://groups.google.com/group/rtc-linux/web/checklist
> before submitting a driver.
Geert Uytterhoeven - June 13, 2010, 5:44 p.m.
On Sun, Jun 13, 2010 at 15:41, Wan ZongShun <mcuos.com@gmail.com> wrote:
> Minior comment below:
>
> 2010/6/13 Geert Uytterhoeven <geert@linux-m68k.org>:
>> The Ricoh RP5C01 RTC contains 26 x 4 bits of NVRAM.
>> Provide access to it via a sysfs "nvram" attribute file.
>>
>> Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
>> --
>> Question: Is a spinlock in priv the right kind of locking?
>>          Should I use e.g. rtc-device.ops_lock instead?
>
> Firstly, this 'Question' text should not put here, please put all
> texts in front of '---'.

I explicitly put it there, as the question was meant for the reviewers only,
and I don't want it to be part of the final checkin comment.

> Secondly, You can not use rtc-device.ops_lock here, if so, it would
> arouse dead lock,
> before the ' rp5c01_read_time()' was called by RTC subsystem upper
> API, rtc-device.ops_lock
> has been required sucessfully, If continue to require the
> rtc-device.ops_lock in ' rp5c01_read_time()',
> the 'lock' will cannot be get, dead lock occurs.

Sorry, my question was not that correctly formulated...
I meant whether it's better to take rtc_device.ops_lock in the nvram
access functions
to synchronize with the RTC access functions (which already take that mutex),
instead of adding a spinlock to priv.

Thanks for your comments!

>> diff --git a/drivers/rtc/rtc-rp5c01.c b/drivers/rtc/rtc-rp5c01.c
>> index a95f733..36eb661 100644
>> --- a/drivers/rtc/rtc-rp5c01.c
>> +++ b/drivers/rtc/rtc-rp5c01.c
>> @@ -63,6 +63,8 @@ enum {
>>  struct rp5c01_priv {
>>        u32 __iomem *regs;
>>        struct rtc_device *rtc;
>> +       spinlock_t lock;        /* against concurrent RTC/NVRAM access */
>> +       struct bin_attribute nvram_attr;
>>  };
>>
>>  static inline unsigned int rp5c01_read(struct rp5c01_priv *priv,
>> @@ -92,6 +94,7 @@ static int rp5c01_read_time(struct device *dev, struct rtc_time *tm)
>>  {
>>        struct rp5c01_priv *priv = dev_get_drvdata(dev);
>>
>> +       spin_lock_irq(&priv->lock);
>>        rp5c01_lock(priv);
>>
>>        tm->tm_sec  = rp5c01_read(priv, RP5C01_10_SECOND) * 10 +
>> @@ -111,6 +114,7 @@ static int rp5c01_read_time(struct device *dev, struct rtc_time *tm)
>>                tm->tm_year += 100;
>>
>>        rp5c01_unlock(priv);
>> +       spin_unlock_irq(&priv->lock);
>>
>>        return rtc_valid_tm(tm);
>>  }
>> @@ -119,6 +123,7 @@ static int rp5c01_set_time(struct device *dev, struct rtc_time *tm)
>>  {
>>        struct rp5c01_priv *priv = dev_get_drvdata(dev);
>>
>> +       spin_lock_irq(&priv->lock);
>>        rp5c01_lock(priv);
>>
>>        rp5c01_write(priv, tm->tm_sec / 10, RP5C01_10_SECOND);
>> @@ -139,6 +144,7 @@ static int rp5c01_set_time(struct device *dev, struct rtc_time *tm)
>>        rp5c01_write(priv, tm->tm_year % 10, RP5C01_1_YEAR);
>>
>>        rp5c01_unlock(priv);
>> +       spin_unlock_irq(&priv->lock);
>>        return 0;
>>  }
>>
>> @@ -147,6 +153,72 @@ static const struct rtc_class_ops rp5c01_rtc_ops = {
>>        .set_time       = rp5c01_set_time,
>>  };
>>
>> +
>> +/*
>> + * The NVRAM is organized as 2 blocks of 13 nibbles of 4 bits.
>> + * We provide access to them like AmigaOS does: the high nibble of each 8-bit
>> + * byte is stored in BLOCK10, the low nibble in BLOCK11.
>> + */
>> +
>> +static ssize_t rp5c01_nvram_read(struct file *filp, struct kobject *kobj,
>> +                                struct bin_attribute *bin_attr,
>> +                                char *buf, loff_t pos, size_t size)
>> +{
>> +       struct device *dev = container_of(kobj, struct device, kobj);
>> +       struct rp5c01_priv *priv = dev_get_drvdata(dev);
>> +       ssize_t count;
>> +
>> +       spin_lock_irq(&priv->lock);
>> +
>> +       for (count = 0; size > 0 && pos < RP5C01_MODE; count++, size--) {
>> +               u8 data;
>> +
>> +               rp5c01_write(priv,
>> +                            RP5C01_MODE_TIMER_EN | RP5C01_MODE_RAM_BLOCK10,
>> +                            RP5C01_MODE);
>> +               data = rp5c01_read(priv, pos) << 4;
>> +               rp5c01_write(priv,
>> +                            RP5C01_MODE_TIMER_EN | RP5C01_MODE_RAM_BLOCK11,
>> +                            RP5C01_MODE);
>> +               data |= rp5c01_read(priv, pos++);
>> +               rp5c01_write(priv, RP5C01_MODE_TIMER_EN | RP5C01_MODE_MODE01,
>> +                            RP5C01_MODE);
>> +               *buf++ = data;
>> +       }
>> +
>> +       spin_unlock_irq(&priv->lock);
>> +       return count;
>> +}
>> +
>> +static ssize_t rp5c01_nvram_write(struct file *filp, struct kobject *kobj,
>> +                                 struct bin_attribute *bin_attr,
>> +                                 char *buf, loff_t pos, size_t size)
>> +{
>> +       struct device *dev = container_of(kobj, struct device, kobj);
>> +       struct rp5c01_priv *priv = dev_get_drvdata(dev);
>> +       ssize_t count;
>> +
>> +       spin_lock_irq(&priv->lock);
>> +
>> +       for (count = 0; size > 0 && pos < RP5C01_MODE; count++, size--) {
>> +               u8 data = *buf++;
>> +
>> +               rp5c01_write(priv,
>> +                            RP5C01_MODE_TIMER_EN | RP5C01_MODE_RAM_BLOCK10,
>> +                            RP5C01_MODE);
>> +               rp5c01_write(priv, data >> 4, pos);
>> +               rp5c01_write(priv,
>> +                            RP5C01_MODE_TIMER_EN | RP5C01_MODE_RAM_BLOCK11,
>> +                            RP5C01_MODE);
>> +               rp5c01_write(priv, data & 0xf, pos++);
>> +               rp5c01_write(priv, RP5C01_MODE_TIMER_EN | RP5C01_MODE_MODE01,
>> +                            RP5C01_MODE);
>> +       }
>> +
>> +       spin_unlock_irq(&priv->lock);
>> +       return count;
>> +}
>> +
>>  static int __init rp5c01_rtc_probe(struct platform_device *dev)
>>  {
>>        struct resource *res;
>> @@ -168,6 +240,15 @@ static int __init rp5c01_rtc_probe(struct platform_device *dev)
>>                goto out_free_priv;
>>        }
>>
>> +       sysfs_bin_attr_init(&priv->nvram_attr);
>> +       priv->nvram_attr.attr.name = "nvram";
>> +       priv->nvram_attr.attr.mode = S_IRUGO | S_IWUSR;
>> +       priv->nvram_attr.read = rp5c01_nvram_read;
>> +       priv->nvram_attr.write = rp5c01_nvram_write;
>> +       priv->nvram_attr.size = RP5C01_MODE;
>> +
>> +       spin_lock_init(&priv->lock);
>> +
>>        rtc = rtc_device_register("rtc-rp5c01", &dev->dev, &rp5c01_rtc_ops,
>>                                  THIS_MODULE);
>>        if (IS_ERR(rtc)) {
>> @@ -177,8 +258,15 @@ static int __init rp5c01_rtc_probe(struct platform_device *dev)
>>
>>        priv->rtc = rtc;
>>        platform_set_drvdata(dev, priv);
>> +
>> +       error = sysfs_create_bin_file(&dev->dev.kobj, &priv->nvram_attr);
>> +       if (error)
>> +               goto out_unregister;
>> +
>>        return 0;
>>
>> +out_unregister:
>> +       rtc_device_unregister(rtc);
>>  out_unmap:
>>        iounmap(priv->regs);
>>  out_free_priv:
>> @@ -190,6 +278,7 @@ static int __exit rp5c01_rtc_remove(struct platform_device *dev)
>>  {
>>        struct rp5c01_priv *priv = platform_get_drvdata(dev);
>>
>> +       sysfs_remove_bin_file(&dev->dev.kobj, &priv->nvram_attr);
>>        rtc_device_unregister(priv->rtc);
>>        iounmap(priv->regs);
>>        kfree(priv);
>> --
>> 1.7.0.4

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds
Geert Uytterhoeven - June 23, 2010, 7:55 p.m.
On Sun, Jun 13, 2010 at 12:12, Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> The Ricoh RP5C01 RTC contains 26 x 4 bits of NVRAM.
> Provide access to it via a sysfs "nvram" attribute file.

I also created a small tool to correct NVRAM checksums, interprete the
contents, and
modify individual NVRAM fields on Amiga 3000/4000.
You can find it at
git://git.kernel.org/pub/scm/linux/kernel/git/geert/amiga-nvram.git.

BTW, does anyone (Arno?) know the meaning of the AMIX-specific bits (32-63)?
battmembitsamix.h just says "See Amix documentation for these bit definitions".
I also couldn't find anything about it at http://www.amigaunix.com/.

Thx!

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds
Geert Uytterhoeven - July 18, 2010, 6:32 p.m.
On Sun, Jun 13, 2010 at 12:12, Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> The Ricoh RP5C01 RTC contains 26 x 4 bits of NVRAM.
> Provide access to it via a sysfs "nvram" attribute file.
>
> Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

Alessandro: Ping?

> --
> Question: Is a spinlock in priv the right kind of locking?
>          Should I use e.g. rtc-device.ops_lock instead?
>
> diff --git a/drivers/rtc/rtc-rp5c01.c b/drivers/rtc/rtc-rp5c01.c
> index a95f733..36eb661 100644
> --- a/drivers/rtc/rtc-rp5c01.c
> +++ b/drivers/rtc/rtc-rp5c01.c
> @@ -63,6 +63,8 @@ enum {
>  struct rp5c01_priv {
>        u32 __iomem *regs;
>        struct rtc_device *rtc;
> +       spinlock_t lock;        /* against concurrent RTC/NVRAM access */
> +       struct bin_attribute nvram_attr;
>  };
>
>  static inline unsigned int rp5c01_read(struct rp5c01_priv *priv,
> @@ -92,6 +94,7 @@ static int rp5c01_read_time(struct device *dev, struct rtc_time *tm)
>  {
>        struct rp5c01_priv *priv = dev_get_drvdata(dev);
>
> +       spin_lock_irq(&priv->lock);
>        rp5c01_lock(priv);
>
>        tm->tm_sec  = rp5c01_read(priv, RP5C01_10_SECOND) * 10 +
> @@ -111,6 +114,7 @@ static int rp5c01_read_time(struct device *dev, struct rtc_time *tm)
>                tm->tm_year += 100;
>
>        rp5c01_unlock(priv);
> +       spin_unlock_irq(&priv->lock);
>
>        return rtc_valid_tm(tm);
>  }
> @@ -119,6 +123,7 @@ static int rp5c01_set_time(struct device *dev, struct rtc_time *tm)
>  {
>        struct rp5c01_priv *priv = dev_get_drvdata(dev);
>
> +       spin_lock_irq(&priv->lock);
>        rp5c01_lock(priv);
>
>        rp5c01_write(priv, tm->tm_sec / 10, RP5C01_10_SECOND);
> @@ -139,6 +144,7 @@ static int rp5c01_set_time(struct device *dev, struct rtc_time *tm)
>        rp5c01_write(priv, tm->tm_year % 10, RP5C01_1_YEAR);
>
>        rp5c01_unlock(priv);
> +       spin_unlock_irq(&priv->lock);
>        return 0;
>  }
>
> @@ -147,6 +153,72 @@ static const struct rtc_class_ops rp5c01_rtc_ops = {
>        .set_time       = rp5c01_set_time,
>  };
>
> +
> +/*
> + * The NVRAM is organized as 2 blocks of 13 nibbles of 4 bits.
> + * We provide access to them like AmigaOS does: the high nibble of each 8-bit
> + * byte is stored in BLOCK10, the low nibble in BLOCK11.
> + */
> +
> +static ssize_t rp5c01_nvram_read(struct file *filp, struct kobject *kobj,
> +                                struct bin_attribute *bin_attr,
> +                                char *buf, loff_t pos, size_t size)
> +{
> +       struct device *dev = container_of(kobj, struct device, kobj);
> +       struct rp5c01_priv *priv = dev_get_drvdata(dev);
> +       ssize_t count;
> +
> +       spin_lock_irq(&priv->lock);
> +
> +       for (count = 0; size > 0 && pos < RP5C01_MODE; count++, size--) {
> +               u8 data;
> +
> +               rp5c01_write(priv,
> +                            RP5C01_MODE_TIMER_EN | RP5C01_MODE_RAM_BLOCK10,
> +                            RP5C01_MODE);
> +               data = rp5c01_read(priv, pos) << 4;
> +               rp5c01_write(priv,
> +                            RP5C01_MODE_TIMER_EN | RP5C01_MODE_RAM_BLOCK11,
> +                            RP5C01_MODE);
> +               data |= rp5c01_read(priv, pos++);
> +               rp5c01_write(priv, RP5C01_MODE_TIMER_EN | RP5C01_MODE_MODE01,
> +                            RP5C01_MODE);
> +               *buf++ = data;
> +       }
> +
> +       spin_unlock_irq(&priv->lock);
> +       return count;
> +}
> +
> +static ssize_t rp5c01_nvram_write(struct file *filp, struct kobject *kobj,
> +                                 struct bin_attribute *bin_attr,
> +                                 char *buf, loff_t pos, size_t size)
> +{
> +       struct device *dev = container_of(kobj, struct device, kobj);
> +       struct rp5c01_priv *priv = dev_get_drvdata(dev);
> +       ssize_t count;
> +
> +       spin_lock_irq(&priv->lock);
> +
> +       for (count = 0; size > 0 && pos < RP5C01_MODE; count++, size--) {
> +               u8 data = *buf++;
> +
> +               rp5c01_write(priv,
> +                            RP5C01_MODE_TIMER_EN | RP5C01_MODE_RAM_BLOCK10,
> +                            RP5C01_MODE);
> +               rp5c01_write(priv, data >> 4, pos);
> +               rp5c01_write(priv,
> +                            RP5C01_MODE_TIMER_EN | RP5C01_MODE_RAM_BLOCK11,
> +                            RP5C01_MODE);
> +               rp5c01_write(priv, data & 0xf, pos++);
> +               rp5c01_write(priv, RP5C01_MODE_TIMER_EN | RP5C01_MODE_MODE01,
> +                            RP5C01_MODE);
> +       }
> +
> +       spin_unlock_irq(&priv->lock);
> +       return count;
> +}
> +
>  static int __init rp5c01_rtc_probe(struct platform_device *dev)
>  {
>        struct resource *res;
> @@ -168,6 +240,15 @@ static int __init rp5c01_rtc_probe(struct platform_device *dev)
>                goto out_free_priv;
>        }
>
> +       sysfs_bin_attr_init(&priv->nvram_attr);
> +       priv->nvram_attr.attr.name = "nvram";
> +       priv->nvram_attr.attr.mode = S_IRUGO | S_IWUSR;
> +       priv->nvram_attr.read = rp5c01_nvram_read;
> +       priv->nvram_attr.write = rp5c01_nvram_write;
> +       priv->nvram_attr.size = RP5C01_MODE;
> +
> +       spin_lock_init(&priv->lock);
> +
>        rtc = rtc_device_register("rtc-rp5c01", &dev->dev, &rp5c01_rtc_ops,
>                                  THIS_MODULE);
>        if (IS_ERR(rtc)) {
> @@ -177,8 +258,15 @@ static int __init rp5c01_rtc_probe(struct platform_device *dev)
>
>        priv->rtc = rtc;
>        platform_set_drvdata(dev, priv);
> +
> +       error = sysfs_create_bin_file(&dev->dev.kobj, &priv->nvram_attr);
> +       if (error)
> +               goto out_unregister;
> +
>        return 0;
>
> +out_unregister:
> +       rtc_device_unregister(rtc);
>  out_unmap:
>        iounmap(priv->regs);
>  out_free_priv:
> @@ -190,6 +278,7 @@ static int __exit rp5c01_rtc_remove(struct platform_device *dev)
>  {
>        struct rp5c01_priv *priv = platform_get_drvdata(dev);
>
> +       sysfs_remove_bin_file(&dev->dev.kobj, &priv->nvram_attr);
>        rtc_device_unregister(priv->rtc);
>        iounmap(priv->regs);
>        kfree(priv);
> --
> 1.7.0.4

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Patch

diff --git a/drivers/rtc/rtc-rp5c01.c b/drivers/rtc/rtc-rp5c01.c
index a95f733..36eb661 100644
--- a/drivers/rtc/rtc-rp5c01.c
+++ b/drivers/rtc/rtc-rp5c01.c
@@ -63,6 +63,8 @@  enum {
 struct rp5c01_priv {
 	u32 __iomem *regs;
 	struct rtc_device *rtc;
+	spinlock_t lock;	/* against concurrent RTC/NVRAM access */
+	struct bin_attribute nvram_attr;
 };
 
 static inline unsigned int rp5c01_read(struct rp5c01_priv *priv,
@@ -92,6 +94,7 @@  static int rp5c01_read_time(struct device *dev, struct rtc_time *tm)
 {
 	struct rp5c01_priv *priv = dev_get_drvdata(dev);
 
+	spin_lock_irq(&priv->lock);
 	rp5c01_lock(priv);
 
 	tm->tm_sec  = rp5c01_read(priv, RP5C01_10_SECOND) * 10 +
@@ -111,6 +114,7 @@  static int rp5c01_read_time(struct device *dev, struct rtc_time *tm)
 		tm->tm_year += 100;
 
 	rp5c01_unlock(priv);
+	spin_unlock_irq(&priv->lock);
 
 	return rtc_valid_tm(tm);
 }
@@ -119,6 +123,7 @@  static int rp5c01_set_time(struct device *dev, struct rtc_time *tm)
 {
 	struct rp5c01_priv *priv = dev_get_drvdata(dev);
 
+	spin_lock_irq(&priv->lock);
 	rp5c01_lock(priv);
 
 	rp5c01_write(priv, tm->tm_sec / 10, RP5C01_10_SECOND);
@@ -139,6 +144,7 @@  static int rp5c01_set_time(struct device *dev, struct rtc_time *tm)
 	rp5c01_write(priv, tm->tm_year % 10, RP5C01_1_YEAR);
 
 	rp5c01_unlock(priv);
+	spin_unlock_irq(&priv->lock);
 	return 0;
 }
 
@@ -147,6 +153,72 @@  static const struct rtc_class_ops rp5c01_rtc_ops = {
 	.set_time	= rp5c01_set_time,
 };
 
+
+/*
+ * The NVRAM is organized as 2 blocks of 13 nibbles of 4 bits.
+ * We provide access to them like AmigaOS does: the high nibble of each 8-bit
+ * byte is stored in BLOCK10, the low nibble in BLOCK11.
+ */
+
+static ssize_t rp5c01_nvram_read(struct file *filp, struct kobject *kobj,
+				 struct bin_attribute *bin_attr,
+				 char *buf, loff_t pos, size_t size)
+{
+	struct device *dev = container_of(kobj, struct device, kobj);
+	struct rp5c01_priv *priv = dev_get_drvdata(dev);
+	ssize_t count;
+
+	spin_lock_irq(&priv->lock);
+
+	for (count = 0; size > 0 && pos < RP5C01_MODE; count++, size--) {
+		u8 data;
+
+		rp5c01_write(priv,
+			     RP5C01_MODE_TIMER_EN | RP5C01_MODE_RAM_BLOCK10,
+			     RP5C01_MODE);
+		data = rp5c01_read(priv, pos) << 4;
+		rp5c01_write(priv,
+			     RP5C01_MODE_TIMER_EN | RP5C01_MODE_RAM_BLOCK11,
+			     RP5C01_MODE);
+		data |= rp5c01_read(priv, pos++);
+		rp5c01_write(priv, RP5C01_MODE_TIMER_EN | RP5C01_MODE_MODE01,
+			     RP5C01_MODE);
+		*buf++ = data;
+	}
+
+	spin_unlock_irq(&priv->lock);
+	return count;
+}
+
+static ssize_t rp5c01_nvram_write(struct file *filp, struct kobject *kobj,
+				  struct bin_attribute *bin_attr,
+				  char *buf, loff_t pos, size_t size)
+{
+	struct device *dev = container_of(kobj, struct device, kobj);
+	struct rp5c01_priv *priv = dev_get_drvdata(dev);
+	ssize_t count;
+
+	spin_lock_irq(&priv->lock);
+
+	for (count = 0; size > 0 && pos < RP5C01_MODE; count++, size--) {
+		u8 data = *buf++;
+
+		rp5c01_write(priv,
+			     RP5C01_MODE_TIMER_EN | RP5C01_MODE_RAM_BLOCK10,
+			     RP5C01_MODE);
+		rp5c01_write(priv, data >> 4, pos);
+		rp5c01_write(priv,
+			     RP5C01_MODE_TIMER_EN | RP5C01_MODE_RAM_BLOCK11,
+			     RP5C01_MODE);
+		rp5c01_write(priv, data & 0xf, pos++);
+		rp5c01_write(priv, RP5C01_MODE_TIMER_EN | RP5C01_MODE_MODE01,
+			     RP5C01_MODE);
+	}
+
+	spin_unlock_irq(&priv->lock);
+	return count;
+}
+
 static int __init rp5c01_rtc_probe(struct platform_device *dev)
 {
 	struct resource *res;
@@ -168,6 +240,15 @@  static int __init rp5c01_rtc_probe(struct platform_device *dev)
 		goto out_free_priv;
 	}
 
+	sysfs_bin_attr_init(&priv->nvram_attr);
+	priv->nvram_attr.attr.name = "nvram";
+	priv->nvram_attr.attr.mode = S_IRUGO | S_IWUSR;
+	priv->nvram_attr.read = rp5c01_nvram_read;
+	priv->nvram_attr.write = rp5c01_nvram_write;
+	priv->nvram_attr.size = RP5C01_MODE;
+
+	spin_lock_init(&priv->lock);
+
 	rtc = rtc_device_register("rtc-rp5c01", &dev->dev, &rp5c01_rtc_ops,
 				  THIS_MODULE);
 	if (IS_ERR(rtc)) {
@@ -177,8 +258,15 @@  static int __init rp5c01_rtc_probe(struct platform_device *dev)
 
 	priv->rtc = rtc;
 	platform_set_drvdata(dev, priv);
+
+	error = sysfs_create_bin_file(&dev->dev.kobj, &priv->nvram_attr);
+	if (error)
+		goto out_unregister;
+
 	return 0;
 
+out_unregister:
+	rtc_device_unregister(rtc);
 out_unmap:
 	iounmap(priv->regs);
 out_free_priv:
@@ -190,6 +278,7 @@  static int __exit rp5c01_rtc_remove(struct platform_device *dev)
 {
 	struct rp5c01_priv *priv = platform_get_drvdata(dev);
 
+	sysfs_remove_bin_file(&dev->dev.kobj, &priv->nvram_attr);
 	rtc_device_unregister(priv->rtc);
 	iounmap(priv->regs);
 	kfree(priv);