[PATCH 0/3] Change ARCH_NR_GPIO into a Kconfig variable

[PATCH 0/3] Change ARCH_NR_GPIO into a Kconfig variable

[Peter De Schrijver]

This patchset converts ARCH_NR_GPIO to a Kconfig variable as suggested by
Russel King. It also converts some platforms to the new model.

Peter De Schrijver (3):
  ARM: ARCH_NR_GPIO: Make ARCH_NR_GPIO a Kconfig variable
  ARM: mach-shmobile: Use CONFIG_ARCH_NR_GPIO
  ARM: mach-ux500 Use CONFIG_ARCH_NR_GPIO

 arch/arm/Kconfig                           |   10 ++++++++++
 arch/arm/include/asm/gpio.h                |    4 ++++
 arch/arm/mach-shmobile/include/mach/gpio.h |    2 --
 arch/arm/mach-ux500/include/mach/gpio.h    |    5 -----
 4 files changed, 14 insertions(+), 7 deletions(-)

-- 
1.7.7.rc0.72.g4b5ea.dirty

[PATCH 1/3] ARM: ARCH_NR_GPIO: Make ARCH_NR_GPIO a Kconfig variable

[Peter De Schrijver]

Change ARCH_NR_GPIO into a Kconfig variable as suggested by Russel King. This
makes ARCH_NR_GPIO single zImage friendly. The default value for tegra is
defined as well.

Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
---
 arch/arm/Kconfig            |    9 +++++++++
 arch/arm/include/asm/gpio.h |    4 ++++
 2 files changed, 13 insertions(+), 0 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 7e8ffe7..924f685 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1507,6 +1507,15 @@ config LOCAL_TIMERS
 	  accounting to be spread across the timer interval, preventing a
 	  "thundering herd" at every timer tick.
 
+config ARCH_NR_GPIO
+	int
+	default 1024 if ARCH_TEGRA
+	default 0
+	help
+	  Maximum number of GPIOs in the system.
+
+	  If unsure, leave the default value.
+
 source kernel/Kconfig.preempt
 
 config HZ
diff --git a/arch/arm/include/asm/gpio.h b/arch/arm/include/asm/gpio.h
index 11ad0bf..7151753 100644
--- a/arch/arm/include/asm/gpio.h
+++ b/arch/arm/include/asm/gpio.h
@@ -1,6 +1,10 @@
 #ifndef _ARCH_ARM_GPIO_H
 #define _ARCH_ARM_GPIO_H
 
+#if CONFIG_ARCH_NR_GPIO > 0
+#define ARCH_NR_GPIO CONFIG_ARCH_NR_GPIO
+#endif
+
 /* not all ARM platforms necessarily support this API ... */
 #include <mach/gpio.h>
 
-- 
1.7.7.rc0.72.g4b5ea.dirty

[PATCH 2/3] ARM: mach-shmobile: Use CONFIG_ARCH_NR_GPIO

[Peter De Schrijver]

Add default value for CONFIG_ARCH_NR_GPIO to Kconfig and remove the definition
in gpio.h.

Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
---
 arch/arm/Kconfig                           |    2 +-
 arch/arm/mach-shmobile/include/mach/gpio.h |    2 --
 2 files changed, 1 insertions(+), 3 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 924f685..b9cfa99 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1509,7 +1509,7 @@ config LOCAL_TIMERS
 
 config ARCH_NR_GPIO
 	int
-	default 1024 if ARCH_TEGRA
+	default 1024 if ARCH_SHMOBILE || ARCH_TEGRA
 	default 0
 	help
 	  Maximum number of GPIOs in the system.
diff --git a/arch/arm/mach-shmobile/include/mach/gpio.h b/arch/arm/mach-shmobile/include/mach/gpio.h
index 7bf0890..de795b4 100644
--- a/arch/arm/mach-shmobile/include/mach/gpio.h
+++ b/arch/arm/mach-shmobile/include/mach/gpio.h
@@ -12,8 +12,6 @@
 
 #include <linux/kernel.h>
 #include <linux/errno.h>
-
-#define ARCH_NR_GPIOS 1024
 #include <linux/sh_pfc.h>
 
 #ifdef CONFIG_GPIOLIB
-- 
1.7.7.rc0.72.g4b5ea.dirty

[PATCH 3/3] ARM: mach-ux500 Use CONFIG_ARCH_NR_GPIO

[Peter De Schrijver]

Add default value for CONFIG_ARCH_NR_GPIO to Kconfig and remove the definition
in gpio.h. We can't remove gpio.h yet as asm/gpio.h still includes it.

Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
---
 arch/arm/Kconfig                        |    1 +
 arch/arm/mach-ux500/include/mach/gpio.h |    5 -----
 2 files changed, 1 insertions(+), 5 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index b9cfa99..8da1f5f 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1510,6 +1510,7 @@ config LOCAL_TIMERS
 config ARCH_NR_GPIO
 	int
 	default 1024 if ARCH_SHMOBILE || ARCH_TEGRA
+	default 350 if ARCH_U8500
 	default 0
 	help
 	  Maximum number of GPIOs in the system.
diff --git a/arch/arm/mach-ux500/include/mach/gpio.h b/arch/arm/mach-ux500/include/mach/gpio.h
index 7389df9..c01ef66 100644
--- a/arch/arm/mach-ux500/include/mach/gpio.h
+++ b/arch/arm/mach-ux500/include/mach/gpio.h
@@ -1,10 +1,5 @@
 #ifndef __ASM_ARCH_GPIO_H
 #define __ASM_ARCH_GPIO_H
 
-/*
- * 288 (#267 is the highest one actually hooked up) onchip GPIOs, plus enough
- * room for a couple of GPIO expanders.
- */
-#define ARCH_NR_GPIOS	350
 
 #endif /* __ASM_ARCH_GPIO_H */
-- 
1.7.7.rc0.72.g4b5ea.dirty

[PATCH 0/3] Change ARCH_NR_GPIO into a Kconfig variable

[Mike Frysinger]

On Thursday 03 November 2011 13:00:44 Peter De Schrijver wrote:
> This patchset converts ARCH_NR_GPIO to a Kconfig variable as suggested by
> Russel King. It also converts some platforms to the new model.
> 
> Peter De Schrijver (3):
>   ARM: ARCH_NR_GPIO: Make ARCH_NR_GPIO a Kconfig variable
>   ARM: mach-shmobile: Use CONFIG_ARCH_NR_GPIO
>   ARM: mach-ux500 Use CONFIG_ARCH_NR_GPIO
> 
>  arch/arm/Kconfig                           |   10 ++++++++++
>  arch/arm/include/asm/gpio.h                |    4 ++++
>  arch/arm/mach-shmobile/include/mach/gpio.h |    2 --
>  arch/arm/mach-ux500/include/mach/gpio.h    |    5 -----
>  4 files changed, 14 insertions(+), 7 deletions(-)

i'm not sure how this is an improvement.  we go from declaring the define in 
the right mach-specific subdir (arch/arm/mach-xxx/include/mach/gpio.h) to an 
arm-global file (arm/Kconfig).  i'd think the ideal would be to keep all the 
mach cruft in the mach-xxx/ subdir.
-mike
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[PATCH 0/3] Change ARCH_NR_GPIO into a Kconfig variable

[Russell King - ARM Linux]

On Thu, Nov 03, 2011 at 06:16:33PM -0400, Mike Frysinger wrote:
> On Thursday 03 November 2011 13:00:44 Peter De Schrijver wrote:
> > This patchset converts ARCH_NR_GPIO to a Kconfig variable as suggested by
> > Russel King. It also converts some platforms to the new model.
> > 
> > Peter De Schrijver (3):
> >   ARM: ARCH_NR_GPIO: Make ARCH_NR_GPIO a Kconfig variable
> >   ARM: mach-shmobile: Use CONFIG_ARCH_NR_GPIO
> >   ARM: mach-ux500 Use CONFIG_ARCH_NR_GPIO
> > 
> >  arch/arm/Kconfig                           |   10 ++++++++++
> >  arch/arm/include/asm/gpio.h                |    4 ++++
> >  arch/arm/mach-shmobile/include/mach/gpio.h |    2 --
> >  arch/arm/mach-ux500/include/mach/gpio.h    |    5 -----
> >  4 files changed, 14 insertions(+), 7 deletions(-)
> 
> i'm not sure how this is an improvement.  we go from declaring the define in 
> the right mach-specific subdir (arch/arm/mach-xxx/include/mach/gpio.h) to an 
> arm-global file (arm/Kconfig).  i'd think the ideal would be to keep all the 
> mach cruft in the mach-xxx/ subdir.

It most certainly is an improvement.

One of the things that we (the ARM community as a whole) is focused on to
is to reduce the amount of code in arch/arm through consolidation, removing
as much duplication as practical between the various SoCs.

One of the other factors that we're also focused on is:
(a) reducing the number of configurations which have to be built to properly
    build-test ARM
(b) reducing the number of kernels which have to be built to support a
    range of ARM platforms

Those two things together dictate that we remove the mach/ header files
which are included outside of the individual mach-* directories, so that
the entire kernel does not depend on anything in those mach/ header files.
That includes mach/gpio.h.

It is the long term goal of Linaro to move the ARM kernel forward to such
a point.

Having ARCH_NR_GPIO definitions in mach/gpio.h is a blocker to both these
efforts and, therefore, must be removed.  Therefore, before we have a
better solution (such as sparse gpios in the same way as we have sparse
irqs) we're going to stop the problem escalating still further by removing
the need for new definitions of this constant in yet more new mach/gpio.h
headers - which could otherwise be empty.

It's one reason why I won't be acking your patch which pushes new stuff
into the mach/gpio.h headers at a time when we're trying to get rid of
them.

[PATCH 0/3] Change ARCH_NR_GPIO into a Kconfig variable

[Mike Frysinger]

On Thursday 03 November 2011 18:44:52 Russell King - ARM Linux wrote:
> On Thu, Nov 03, 2011 at 06:16:33PM -0400, Mike Frysinger wrote:
> > On Thursday 03 November 2011 13:00:44 Peter De Schrijver wrote:
> > > This patchset converts ARCH_NR_GPIO to a Kconfig variable as suggested
> > > by Russel King. It also converts some platforms to the new model.
> > > 
> > > Peter De Schrijver (3):
> > >   ARM: ARCH_NR_GPIO: Make ARCH_NR_GPIO a Kconfig variable
> > >   ARM: mach-shmobile: Use CONFIG_ARCH_NR_GPIO
> > >   ARM: mach-ux500 Use CONFIG_ARCH_NR_GPIO
> > >  
> > >  arch/arm/Kconfig                           |   10 ++++++++++
> > >  arch/arm/include/asm/gpio.h                |    4 ++++
> > >  arch/arm/mach-shmobile/include/mach/gpio.h |    2 --
> > >  arch/arm/mach-ux500/include/mach/gpio.h    |    5 -----
> > >  4 files changed, 14 insertions(+), 7 deletions(-)
> > 
> > i'm not sure how this is an improvement.  we go from declaring the define
> > in the right mach-specific subdir
> > (arch/arm/mach-xxx/include/mach/gpio.h) to an arm-global file
> > (arm/Kconfig).  i'd think the ideal would be to keep all the mach cruft
> > in the mach-xxx/ subdir.
> 
> It most certainly is an improvement.
> 
> One of the things that we (the ARM community as a whole) is focused on to
> is to reduce the amount of code in arch/arm through consolidation, removing
> as much duplication as practical between the various SoCs.
> 
> One of the other factors that we're also focused on is:
> (a) reducing the number of configurations which have to be built to
> properly build-test ARM
> (b) reducing the number of kernels which have to be built to support a
>     range of ARM platforms

i'm aware of these efforts, but i don't see how this Kconfig solution gets you 
there.  it's still a single define depending on arch-specific knobs.  now, if 
this were treated as a max value that was based on all the arch needs, it's 
now useful across SoCs.

> It's one reason why I won't be acking your patch which pushes new stuff
> into the mach/gpio.h headers at a time when we're trying to get rid of
> them.

i already described in the patch that it was an improvement, and that it makes 
things even easier to move away from mach gpio.h.
-mike
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[PATCH 0/3] Change ARCH_NR_GPIO into a Kconfig variable

[Mike Frysinger]

On Thursday 03 November 2011 19:07:42 Mike Frysinger wrote:
> i'm aware of these efforts, but i don't see how this Kconfig solution gets
> you there.  it's still a single define depending on arch-specific knobs. 
> now, if this were treated as a max value that was based on all the arch
> needs, it's now useful across SoCs.

s/arch/mach/g
-mike
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[PATCH 0/3] Change ARCH_NR_GPIO into a Kconfig variable

[Russell King - ARM Linux]

On Thu, Nov 03, 2011 at 07:07:42PM -0400, Mike Frysinger wrote:
> On Thursday 03 November 2011 18:44:52 Russell King - ARM Linux wrote:
> > It most certainly is an improvement.
> > 
> > One of the things that we (the ARM community as a whole) is focused on to
> > is to reduce the amount of code in arch/arm through consolidation, removing
> > as much duplication as practical between the various SoCs.
> > 
> > One of the other factors that we're also focused on is:
> > (a) reducing the number of configurations which have to be built to
> > properly build-test ARM
> > (b) reducing the number of kernels which have to be built to support a
> >     range of ARM platforms
> 
> i'm aware of these efforts, but i don't see how this Kconfig solution gets you 
> there.  it's still a single define depending on arch-specific knobs.  now, if 
> this were treated as a max value that was based on all the arch needs, it's 
> now useful across SoCs.

(a) you need to read other discussions on this subject which have already
been had on linux-arm-kernel.  Essentially I've had it in the neck for
less than 128 bytes of needless bloat.  So when I'm faced with 8K of
bloat, what do you think my reaction will be?  Roll over and capitulate
only to get it in the neck again?  Or come up with an easy solution?

(b) that's effectively what it is - if you understand what's going on with
the 'default' statements.

For any option, there can be multiple 'default' statements:

- default value: "default" <expr> ["if" <expr>]
  A config option can have any number of default values. If multiple
  default values are visible, only the first defined one is active.
...
  Optionally, dependencies only for this default value can be added with
  "if".

Now, because of that well defined order, if we do this:

config FOO
	int
	default 1024 if A
	default 512 if B
	default 256

Then we end up with this truth table:

A B FOO
n n 256
n y 512
y n 1024
y y 1024

Which - provided the order is highest value first - gets us the highest
value for this variable dependent on which platforms have been selected.

And - given that we don't have many which require this treatment, this
is a sane solution to the problem.  Not only that but it's one which can
be trivially deleted from one file if and when we have sparse gpio.

[PATCH 0/3] Change ARCH_NR_GPIO into a Kconfig variable

[Mike Frysinger]

On Thursday 03 November 2011 19:17:07 Russell King - ARM Linux wrote:
> (b) that's effectively what it is - if you understand what's going on with
> the 'default' statements.
> 
> For any option, there can be multiple 'default' statements:

thanks, i wasn't aware of the cascading nature of the default keyword
-mike
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[PATCH 0/3] Change ARCH_NR_GPIO into a Kconfig variable

[Peter De Schrijver]

On Thu, Nov 03, 2011 at 06:00:44PM +0100, Peter De Schrijver wrote:
> This patchset converts ARCH_NR_GPIO to a Kconfig variable as suggested by
> Russel King. It also converts some platforms to the new model.
> 
> Peter De Schrijver (3):
>   ARM: ARCH_NR_GPIO: Make ARCH_NR_GPIO a Kconfig variable
>   ARM: mach-shmobile: Use CONFIG_ARCH_NR_GPIO
>   ARM: mach-ux500 Use CONFIG_ARCH_NR_GPIO

Ping? What should we do with this?

Cheers,

Peter.

[PATCH 0/3] Change ARCH_NR_GPIO into a Kconfig variable

[Linus Walleij]

On Tue, Nov 29, 2011 at 7:46 AM, Peter De Schrijver
<pdeschrijver@nvidia.com> wrote:
> On Thu, Nov 03, 2011 at 06:00:44PM +0100, Peter De Schrijver wrote:
>> This patchset converts ARCH_NR_GPIO to a Kconfig variable as suggested by
>> Russel King. It also converts some platforms to the new model.
>>
>> Peter De Schrijver (3):
>> ? ARM: ARCH_NR_GPIO: Make ARCH_NR_GPIO a Kconfig variable
>> ? ARM: mach-shmobile: Use CONFIG_ARCH_NR_GPIO
>> ? ARM: mach-ux500 Use CONFIG_ARCH_NR_GPIO
>
> Ping? What should we do with this?

Acked-by: Linus Walleij <linus.walleij@linaro.org>

Put it into Russell's patch tracker.

Yours,
Linus Walleij

[PATCH 0/3] Change ARCH_NR_GPIO into a Kconfig variable

[Russell King - ARM Linux]

On Tue, Nov 29, 2011 at 09:40:27AM +0100, Linus Walleij wrote:
> On Tue, Nov 29, 2011 at 7:46 AM, Peter De Schrijver
> <pdeschrijver@nvidia.com> wrote:
> > On Thu, Nov 03, 2011 at 06:00:44PM +0100, Peter De Schrijver wrote:
> >> This patchset converts ARCH_NR_GPIO to a Kconfig variable as suggested by
> >> Russel King. It also converts some platforms to the new model.
> >>
> >> Peter De Schrijver (3):
> >> ? ARM: ARCH_NR_GPIO: Make ARCH_NR_GPIO a Kconfig variable
> >> ? ARM: mach-shmobile: Use CONFIG_ARCH_NR_GPIO
> >> ? ARM: mach-ux500 Use CONFIG_ARCH_NR_GPIO
> >
> > Ping? What should we do with this?
> 
> Acked-by: Linus Walleij <linus.walleij@linaro.org>
> 
> Put it into Russell's patch tracker.

Or we could wait for Grant to reappear and take it.