[PATCH 0/6] rtc: generic: follow up for COMPILE_TEST

[PATCH 0/6] rtc: generic: follow up for COMPILE_TEST

[Arnd Bergmann]

Today's linux-next kernel allowed building the rtc-generic
driver (and most other rtc drivers) on all architectures,
but this caused some errors on architectures without asm/rtc.h.

This series reworks that driver to avoid the dependency,
and simplifies all four implementations. My first approach
was to split the driver into four separate drivers, but
that didn't feel right when three of them have their own
multiplexors.

The first five patches can be applied independent of one other,
while patch 6 is optional and can be applied when all others
are merged. Alternatively, they can all go in through the
rtc tree. I compile-tested only the powerpc and sh targets for
which I happened to have cross-compilers installed.

	Arnd

[PATCH 1/6] rtc: generic: allow building on all architectures

[Arnd Bergmann]

There are four architectures using this driver, but since we can
build it with COMPILE_TEST, we should try dealing with the absence
of the asm/rtc.h header file, to avoid getting a build error:

drivers/rtc/rtc-generic.c:12:21: fatal error: asm/rtc.h: No such file or directory

This creates an alternative use of the driver, allowing architectures
to pass a set of rtc_class_ops in platform data. We can convert the
four architectures to use this and then remove the original
code.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/rtc/rtc-generic.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/rtc/rtc-generic.c b/drivers/rtc/rtc-generic.c
index e782ebd719b2..d726c6aa96a8 100644
--- a/drivers/rtc/rtc-generic.c
+++ b/drivers/rtc/rtc-generic.c
@@ -9,6 +9,8 @@
 #include <linux/platform_device.h>
 #include <linux/rtc.h>
 
+#if defined(CONFIG_M68K) || defined(CONFIG_PARISC) || \
+    defined(CONFIG_PPC) || defined(CONFIG_SUPERH32)
 #include <asm/rtc.h>
 
 static int generic_get_time(struct device *dev, struct rtc_time *tm)
@@ -33,13 +35,21 @@ static const struct rtc_class_ops generic_rtc_ops = {
 	.read_time = generic_get_time,
 	.set_time = generic_set_time,
 };
+#else
+#define generic_rtc_ops *(struct rtc_class_ops*)NULL
+#endif
 
 static int __init generic_rtc_probe(struct platform_device *dev)
 {
 	struct rtc_device *rtc;
+	const struct rtc_class_ops *ops;
+
+	ops = dev_get_platdata(&dev->dev);
+	if (!ops)
+		ops = &generic_rtc_ops;
 
 	rtc = devm_rtc_device_register(&dev->dev, "rtc-generic",
-					&generic_rtc_ops, THIS_MODULE);
+					ops, THIS_MODULE);
 	if (IS_ERR(rtc))
 		return PTR_ERR(rtc);
 
-- 
2.7.0

Re: [PATCH 1/6] rtc: generic: allow building on all architectures

[Geert Uytterhoeven]

Hi Arnd,

On Tue, Mar 1, 2016 at 5:59 PM, Arnd Bergmann <arnd@arndb.de> wrote:
> There are four architectures using this driver, but since we can
> build it with COMPILE_TEST, we should try dealing with the absence
> of the asm/rtc.h header file, to avoid getting a build error:
>
> drivers/rtc/rtc-generic.c:12:21: fatal error: asm/rtc.h: No such file or directory
>
> This creates an alternative use of the driver, allowing architectures
> to pass a set of rtc_class_ops in platform data. We can convert the
> four architectures to use this and then remove the original
> code.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  drivers/rtc/rtc-generic.c | 12 +++++++++++-
>  1 file changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/rtc/rtc-generic.c b/drivers/rtc/rtc-generic.c
> index e782ebd719b2..d726c6aa96a8 100644
> --- a/drivers/rtc/rtc-generic.c
> +++ b/drivers/rtc/rtc-generic.c
> @@ -9,6 +9,8 @@
>  #include <linux/platform_device.h>
>  #include <linux/rtc.h>
>
> +#if defined(CONFIG_M68K) || defined(CONFIG_PARISC) || \
> +    defined(CONFIG_PPC) || defined(CONFIG_SUPERH32)
>  #include <asm/rtc.h>
>
>  static int generic_get_time(struct device *dev, struct rtc_time *tm)
> @@ -33,13 +35,21 @@ static const struct rtc_class_ops generic_rtc_ops = {
>         .read_time = generic_get_time,
>         .set_time = generic_set_time,
>  };
> +#else
> +#define generic_rtc_ops *(struct rtc_class_ops*)NULL
> +#endif
>
>  static int __init generic_rtc_probe(struct platform_device *dev)
>  {
>         struct rtc_device *rtc;
> +       const struct rtc_class_ops *ops;
> +
> +       ops = dev_get_platdata(&dev->dev);
> +       if (!ops)
> +               ops = &generic_rtc_ops;

I hope no compiler version treats "&*(struct rtc_class_ops*)NULL" as
undefined behavior?

>
>         rtc = devm_rtc_device_register(&dev->dev, "rtc-generic",
> -                                       &generic_rtc_ops, THIS_MODULE);
> +                                       ops, THIS_MODULE);
>         if (IS_ERR(rtc))
>                 return PTR_ERR(rtc);

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

Re: [PATCH 1/6] rtc: generic: allow building on all architectures

[Arnd Bergmann]

On Wednesday 02 March 2016 09:57:27 Geert Uytterhoeven wrote:
> > @@ -33,13 +35,21 @@ static const struct rtc_class_ops generic_rtc_ops = {
> >         .read_time = generic_get_time,
> >         .set_time = generic_set_time,
> >  };
> > +#else
> > +#define generic_rtc_ops *(struct rtc_class_ops*)NULL
> > +#endif
> >
> >  static int __init generic_rtc_probe(struct platform_device *dev)
> >  {
> >         struct rtc_device *rtc;
> > +       const struct rtc_class_ops *ops;
> > +
> > +       ops = dev_get_platdata(&dev->dev);
> > +       if (!ops)
> > +               ops = &generic_rtc_ops;
> 
> I hope no compiler version treats "&*(struct rtc_class_ops*)NULL" as
> undefined behavior?

It's a bit odd, but I think it's syntactically correct C, and not
much too different from 

#define offsetof(TYPE, MEMBER)  ((size_t)&((TYPE *)0)->MEMBER)

is it? My last patch gets rid of it again.

	Arnd

Re: [PATCH 1/6] rtc: generic: allow building on all architectures

[Andreas Schwab]

Geert Uytterhoeven <geert@linux-m68k.org> writes:

>> +#else
>> +#define generic_rtc_ops *(struct rtc_class_ops*)NULL
>> +#endif
>>
>>  static int __init generic_rtc_probe(struct platform_device *dev)
>>  {
>>         struct rtc_device *rtc;
>> +       const struct rtc_class_ops *ops;
>> +
>> +       ops = dev_get_platdata(&dev->dev);
>> +       if (!ops)
>> +               ops = &generic_rtc_ops;
>
> I hope no compiler version treats "&*(struct rtc_class_ops*)NULL" as
> undefined behavior?

Yes, that is guaranteed, the operations cancel each other (6.5.3.2#3: If
the operand is the result of a unary * operator, neither that operator
nor the & operator is evaluated and the result is as if both were
omitted).

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."

Re: [PATCH 1/6] rtc: generic: allow building on all architectures

[Geert Uytterhoeven]

On Wed, Mar 2, 2016 at 10:28 AM, Andreas Schwab <schwab@linux-m68k.org> wrote:
> Geert Uytterhoeven <geert@linux-m68k.org> writes:
>
>>> +#else
>>> +#define generic_rtc_ops *(struct rtc_class_ops*)NULL
>>> +#endif
>>>
>>>  static int __init generic_rtc_probe(struct platform_device *dev)
>>>  {
>>>         struct rtc_device *rtc;
>>> +       const struct rtc_class_ops *ops;
>>> +
>>> +       ops = dev_get_platdata(&dev->dev);
>>> +       if (!ops)
>>> +               ops = &generic_rtc_ops;
>>
>> I hope no compiler version treats "&*(struct rtc_class_ops*)NULL" as
>> undefined behavior?
>
> Yes, that is guaranteed, the operations cancel each other (6.5.3.2#3: If
> the operand is the result of a unary * operator, neither that operator
> nor the & operator is evaluated and the result is as if both were
> omitted).

Thanks for confirming.

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 2/6] m68k: rtc: provide rtc_class_ops directly

[Arnd Bergmann]

The rtc-generic driver provides an architecture specific
wrapper on top of the generic rtc_class_ops abstraction,
and m68k has another abstraction on top, which is a bit
silly.

This changes the m68k rtc-generic device to provide its
rtc_class_ops directly, to reduce the number of layers
by one.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 arch/m68k/kernel/time.c | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/arch/m68k/kernel/time.c b/arch/m68k/kernel/time.c
index 3857737e3958..773b2187210d 100644
--- a/arch/m68k/kernel/time.c
+++ b/arch/m68k/kernel/time.c
@@ -87,6 +87,23 @@ void read_persistent_clock(struct timespec *ts)
 }
 
 #ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
+static int rtc_generic_get_time(struct device *dev, struct rtc_time *tm)
+{
+	mach_hwclk(0, tm);
+	return rtc_valid_tm(tm);
+}
+
+static int rtc_generic_set_time(struct device *dev, struct rtc_time *tm)
+{
+	if (mach_hwclk(1, tm) < 0)
+		return -EOPNOTSUPP;
+	return 0;
+}
+
+static const struct rtc_class_ops generic_rtc_ops = {
+	.read_time = rtc_generic_get_time,
+	.set_time = rtc_generic_set_time,
+};
 
 static int __init rtc_init(void)
 {
@@ -95,7 +112,10 @@ static int __init rtc_init(void)
 	if (!mach_hwclk)
 		return -ENODEV;
 
-	pdev = platform_device_register_simple("rtc-generic", -1, NULL, 0);
+	/* or just call devm_rtc_device_register instead? */
+	pdev = platform_device_register_data(NULL, "rtc-generic", -1,
+					     &generic_rtc_ops,
+					     sizeof(generic_rtc_ops));
 	return PTR_ERR_OR_ZERO(pdev);
 }
 
-- 
2.7.0

[PATCH 3/6] powerpc: rtc: provide rtc_class_ops directly

[Arnd Bergmann]

The rtc-generic driver provides an architecture specific
wrapper on top of the generic rtc_class_ops abstraction,
and powerpc has another abstraction on top, which is a bit
silly.

This changes the powerpc rtc-generic device to provide its
rtc_class_ops directly, to reduce the number of layers
by one.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 arch/powerpc/kernel/time.c | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 81b0900a39ee..84a1228be617 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -1080,6 +1080,28 @@ void calibrate_delay(void)
 	loops_per_jiffy = tb_ticks_per_jiffy;
 }
 
+static int rtc_generic_get_time(struct device *dev, struct rtc_time *tm)
+{
+	ppc_md.get_rtc_time(tm);
+	return rtc_valid_tm(tm);
+}
+
+static int rtc_generic_set_time(struct device *dev, struct rtc_time *tm)
+{
+	if (!ppc_md.set_rtc_time)
+		return -EOPNOTSUPP;
+
+	if (ppc_md.set_rtc_time(tm) < 0)
+		return -EOPNOTSUPP;
+
+	return 0;
+}
+
+static const struct rtc_class_ops rtc_generic_ops = {
+	.read_time = rtc_generic_get_time,
+	.set_time = rtc_generic_set_time,
+};
+
 static int __init rtc_init(void)
 {
 	struct platform_device *pdev;
@@ -1087,7 +1109,9 @@ static int __init rtc_init(void)
 	if (!ppc_md.get_rtc_time)
 		return -ENODEV;
 
-	pdev = platform_device_register_simple("rtc-generic", -1, NULL, 0);
+	pdev = platform_device_register_data(NULL, "rtc-generic", -1,
+					     &rtc_generic_ops,
+					     sizeof(rtc_generic_ops));
 
 	return PTR_ERR_OR_ZERO(pdev);
 }
-- 
2.7.0

Re: [PATCH 3/6] powerpc: rtc: provide rtc_class_ops directly

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 1047 bytes --]

Hi Arnd,

[auto build test ERROR on abelloni/rtc-next]
[also build test ERROR on v4.5-rc6 next-20160301]
[if your patch is applied to the wrong git tree, please drop us a note to help improving the system]

url:    https://github.com/0day-ci/linux/commits/Arnd-Bergmann/rtc-generic-follow-up-for-COMPILE_TEST/20160302-011032
base:   https://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux.git rtc-next
config: powerpc-allnoconfig (attached as .config)
reproduce:
        wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=powerpc 

All errors (new ones prefixed by >>):

   arch/powerpc/kernel/built-in.o: In function `rtc_generic_get_time':
>> time.c:(.text+0x4c58): undefined reference to `rtc_valid_tm'

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/octet-stream, Size: 5708 bytes --]

Re: [PATCH 3/6] powerpc: rtc: provide rtc_class_ops directly

[Arnd Bergmann]

On Wednesday 02 March 2016 02:37:14 kbuild test robot wrote:
> [auto build test ERROR on abelloni/rtc-next]
> [also build test ERROR on v4.5-rc6 next-20160301]
> [if your patch is applied to the wrong git tree, please drop us a note to help improving the system]
> 
> url:    https://github.com/0day-ci/linux/commits/Arnd-Bergmann/rtc-generic-follow-up-for-COMPILE_TEST/20160302-011032
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux.git rtc-next
> config: powerpc-allnoconfig (attached as .config)
> reproduce:
>         wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # save the attached .config to linux build tree
>         make.cross ARCH=powerpc 
> 
> All errors (new ones prefixed by >>):
> 
>    arch/powerpc/kernel/built-in.o: In function `rtc_generic_get_time':
> >> time.c:(.text+0x4c58): undefined reference to `rtc_valid_tm'
> 

I fixed up the powerpc and parisc patches now, will resend them
after getting some feedback on the overall approach.

	Arnd

[PATCH 4/6] parisc: rtc: provide rtc_class_ops directly

[Arnd Bergmann]

The rtc-generic driver provides an architecture specific
wrapper on top of the generic rtc_class_ops abstraction,
and on pa-risc, that is implemented using an open-coded
version of rtc_time_to_tm/rtc_tm_to_time.

This changes the parisc rtc-generic device to provide its
rtc_class_ops directly, using the normal helper functions,
which makes this y2038 safe (on 32-bit) and simplifies
the implementation.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 arch/parisc/kernel/time.c | 35 ++++++++++++++++++++++++++++++++++-
 1 file changed, 34 insertions(+), 1 deletion(-)

diff --git a/arch/parisc/kernel/time.c b/arch/parisc/kernel/time.c
index 400acac0a304..176ef5c2aa82 100644
--- a/arch/parisc/kernel/time.c
+++ b/arch/parisc/kernel/time.c
@@ -12,6 +12,7 @@
  */
 #include <linux/errno.h>
 #include <linux/module.h>
+#include <linux/rtc.h>
 #include <linux/sched.h>
 #include <linux/kernel.h>
 #include <linux/param.h>
@@ -224,11 +225,43 @@ void __init start_cpu_itimer(void)
 	per_cpu(cpu_data, cpu).it_value = next_tick;
 }
 
+static int rtc_generic_get_time(struct device *dev, struct rtc_time *tm)
+{
+	struct pdc_tod tod_data;
+
+	memset(wtime, 0, sizeof(*wtime));
+	if (pdc_tod_read(&tod_data) < 0)
+		return -EOPNOTSUPP;
+
+	/* we treat tod_sec as unsigned, so this can work until year 2106 */
+	rtc_time64_to_tm(tod_data.tod_sec, &tm);
+	return rtc_valid_tm(tm);
+}
+
+static int rtc_generic_set_time(struct device *dev, struct rtc_time *tm)
+{
+	time64_t secs = rtc_tm_to_time64(tm);
+
+	if (pdc_tod_set(secs, 0) < 0)
+		return -EOPNOTSUPP;
+
+	return 0;
+}
+
+static const struct rtc_class_ops rtc_generic_ops = {
+	.read_time = rtc_generic_get_time,
+	.set_time = rtc_generic_set_time,
+};
+
 static int __init rtc_init(void)
 {
 	struct platform_device *pdev;
 
-	pdev = platform_device_register_simple("rtc-generic", -1, NULL, 0);
+	pdev = platform_device_register_data(NULL, "rtc-generic", -1,
+					     &rtc_generic_ops,
+					     sizeof(rtc_generic_ops));
+
+
 	return PTR_ERR_OR_ZERO(pdev);
 }
 device_initcall(rtc_init);
-- 
2.7.0

Re: [PATCH 4/6] parisc: rtc: provide rtc_class_ops directly

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 2165 bytes --]

Hi Arnd,

[auto build test ERROR on abelloni/rtc-next]
[also build test ERROR on v4.5-rc6 next-20160301]
[if your patch is applied to the wrong git tree, please drop us a note to help improving the system]

url:    https://github.com/0day-ci/linux/commits/Arnd-Bergmann/rtc-generic-follow-up-for-COMPILE_TEST/20160302-011032
base:   https://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux.git rtc-next
config: parisc-allyesconfig (attached as .config)
reproduce:
        wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=parisc 

All error/warnings (new ones prefixed by >>):

   arch/parisc/kernel/time.c: In function 'rtc_generic_get_time':
>> arch/parisc/kernel/time.c:232:9: error: 'wtime' undeclared (first use in this function)
     memset(wtime, 0, sizeof(*wtime));
            ^
   arch/parisc/kernel/time.c:232:9: note: each undeclared identifier is reported only once for each function it appears in
>> arch/parisc/kernel/time.c:237:2: warning: passing argument 2 of 'rtc_time64_to_tm' from incompatible pointer type
     rtc_time64_to_tm(tod_data.tod_sec, &tm);
     ^
   In file included from arch/parisc/kernel/time.c:15:0:
   include/linux/rtc.h:23:13: note: expected 'struct rtc_time *' but argument is of type 'struct rtc_time **'
    extern void rtc_time64_to_tm(time64_t time, struct rtc_time *tm);
                ^

vim +/wtime +232 arch/parisc/kernel/time.c

   226	}
   227	
   228	static int rtc_generic_get_time(struct device *dev, struct rtc_time *tm)
   229	{
   230		struct pdc_tod tod_data;
   231	
 > 232		memset(wtime, 0, sizeof(*wtime));
   233		if (pdc_tod_read(&tod_data) < 0)
   234			return -EOPNOTSUPP;
   235	
   236		/* we treat tod_sec as unsigned, so this can work until year 2106 */
 > 237		rtc_time64_to_tm(tod_data.tod_sec, &tm);
   238		return rtc_valid_tm(tm);
   239	}
   240	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/octet-stream, Size: 43840 bytes --]

Re: [PATCH 4/6] parisc: rtc: provide rtc_class_ops directly

[Alexandre Belloni]

On 01/03/2016 at 18:00:00 +0100, Arnd Bergmann wrote :
> -	pdev = platform_device_register_simple("rtc-generic", -1, NULL, 0);
> +	pdev = platform_device_register_data(NULL, "rtc-generic", -1,
> +					     &rtc_generic_ops,
> +					     sizeof(rtc_generic_ops));
> +
> +

spurious blank line

>  	return PTR_ERR_OR_ZERO(pdev);
>  }
>  device_initcall(rtc_init);
> -- 
> 2.7.0
> 

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

[PATCH 5/6] sh: rtc: provide rtc_class_ops directly

[Arnd Bergmann]

The rtc-generic driver provides an architecture specific
wrapper on top of the generic rtc_class_ops abstraction,
and on sh, that goes through another indirection using
the rtc_sh_get_time/rtc_sh_set_time functions.

This changes the sh rtc-generic device to provide its
rtc_class_ops directly, skipping one of the abstraction
levels.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 arch/sh/kernel/time.c | 32 +++++++++++++++++++-------------
 1 file changed, 19 insertions(+), 13 deletions(-)

diff --git a/arch/sh/kernel/time.c b/arch/sh/kernel/time.c
index d6d0a986c6e9..92cd676970d9 100644
--- a/arch/sh/kernel/time.c
+++ b/arch/sh/kernel/time.c
@@ -50,27 +50,30 @@ int update_persistent_clock(struct timespec now)
 }
 #endif
 
-unsigned int get_rtc_time(struct rtc_time *tm)
+static int rtc_generic_get_time(struct device *dev, struct rtc_time *tm)
 {
-	if (rtc_sh_get_time != null_rtc_get_time) {
-		struct timespec tv;
+	struct timespec tv;
 
-		rtc_sh_get_time(&tv);
-		rtc_time_to_tm(tv.tv_sec, tm);
-	}
-
-	return RTC_24H;
+	rtc_sh_get_time(&tv);
+	rtc_time_to_tm(tv.tv_sec, tm);
+	return 0;
 }
-EXPORT_SYMBOL(get_rtc_time);
 
-int set_rtc_time(struct rtc_time *tm)
+static int rtc_generic_set_time(struct device *dev, struct rtc_time *tm)
 {
 	unsigned long secs;
 
 	rtc_tm_to_time(tm, &secs);
-	return rtc_sh_set_time(secs);
+	if (!rtc_sh_set_time || rtc_sh_set_time(secs) < 0)
+		return -EOPNOTSUPP;
+
+	return 0;
 }
-EXPORT_SYMBOL(set_rtc_time);
+
+static const struct rtc_class_ops rtc_generic_ops = {
+	.read_time = rtc_generic_get_time,
+	.set_time = rtc_generic_set_time,
+};
 
 static int __init rtc_generic_init(void)
 {
@@ -79,7 +82,10 @@ static int __init rtc_generic_init(void)
 	if (rtc_sh_get_time == null_rtc_get_time)
 		return -ENODEV;
 
-	pdev = platform_device_register_simple("rtc-generic", -1, NULL, 0);
+	pdev = platform_device_register_data(NULL, "rtc-generic", -1,
+					     &rtc_generic_ops,
+					     sizeof(rtc_generic_ops));
+
 
 	return PTR_ERR_OR_ZERO(pdev);
 }
-- 
2.7.0

[PATCH 6/6] rtc: generic: remove get_rtc_time/set_rtc_time wrappers

[Arnd Bergmann]

All architectures using this driver are now converted to
provide their own operations, so this one can be turned
into a trivial stub driver relying on its platform data.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/rtc/rtc-generic.c | 36 +-----------------------------------
 1 file changed, 1 insertion(+), 35 deletions(-)

diff --git a/drivers/rtc/rtc-generic.c b/drivers/rtc/rtc-generic.c
index d726c6aa96a8..1bf5d2347928 100644
--- a/drivers/rtc/rtc-generic.c
+++ b/drivers/rtc/rtc-generic.c
@@ -9,44 +9,10 @@
 #include <linux/platform_device.h>
 #include <linux/rtc.h>
 
-#if defined(CONFIG_M68K) || defined(CONFIG_PARISC) || \
-    defined(CONFIG_PPC) || defined(CONFIG_SUPERH32)
-#include <asm/rtc.h>
-
-static int generic_get_time(struct device *dev, struct rtc_time *tm)
-{
-	unsigned int ret = get_rtc_time(tm);
-
-	if (ret & RTC_BATT_BAD)
-		return -EOPNOTSUPP;
-
-	return rtc_valid_tm(tm);
-}
-
-static int generic_set_time(struct device *dev, struct rtc_time *tm)
-{
-	if (set_rtc_time(tm) < 0)
-		return -EOPNOTSUPP;
-
-	return 0;
-}
-
-static const struct rtc_class_ops generic_rtc_ops = {
-	.read_time = generic_get_time,
-	.set_time = generic_set_time,
-};
-#else
-#define generic_rtc_ops *(struct rtc_class_ops*)NULL
-#endif
-
 static int __init generic_rtc_probe(struct platform_device *dev)
 {
 	struct rtc_device *rtc;
-	const struct rtc_class_ops *ops;
-
-	ops = dev_get_platdata(&dev->dev);
-	if (!ops)
-		ops = &generic_rtc_ops;
+	const struct rtc_class_ops *ops = dev_get_platdata(&dev->dev);
 
 	rtc = devm_rtc_device_register(&dev->dev, "rtc-generic",
 					ops, THIS_MODULE);
-- 
2.7.0

Re: [PATCH 0/6] rtc: generic: follow up for COMPILE_TEST

[Alexandre Belloni]

Hi,

On 01/03/2016 at 17:59:56 +0100, Arnd Bergmann wrote :
> Today's linux-next kernel allowed building the rtc-generic
> driver (and most other rtc drivers) on all architectures,
> but this caused some errors on architectures without asm/rtc.h.
> 
> This series reworks that driver to avoid the dependency,
> and simplifies all four implementations. My first approach
> was to split the driver into four separate drivers, but
> that didn't feel right when three of them have their own
> multiplexors.
> 
> The first five patches can be applied independent of one other,
> while patch 6 is optional and can be applied when all others
> are merged. Alternatively, they can all go in through the
> rtc tree. I compile-tested only the powerpc and sh targets for
> which I happened to have cross-compilers installed.
> 

I like this approach. Maybe you can also remove the now unnecessary
definitions from the various asm/rtc.h.

I have a small nitpick on the parisc patch.

I'll take the first patch, no need to resend that one.

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