| Message ID | 1410790185-31101-1-git-send-email-mika.westerberg@linux.intel.com |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
On Monday 15 September 2014, Mika Westerberg wrote: > Some newer Intel SoCs, like Braswell already have more than 256 GPIOs > available so the default limit is exceeded. Instead of adding more > architecture specific gpio.h files with custom ARCH_NR_GPIOs we increase > the gpiolib default limit to be twice the current. > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> > --- > Changes to previous version is that now we increase the common limit > instead of adding x86 specific gpio.h Can you please include the reasoning for this decision in the changeset description? I'm sure you have your reasons, but from the text above, it sounds like a rather bad idea. What other architectures are impacted by this, and what is the kernel size cost for it on those architectures? Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Sep 15, 2014 at 06:50:34PM +0200, Arnd Bergmann wrote: > On Monday 15 September 2014, Mika Westerberg wrote: > > Some newer Intel SoCs, like Braswell already have more than 256 GPIOs > > available so the default limit is exceeded. Instead of adding more > > architecture specific gpio.h files with custom ARCH_NR_GPIOs we increase > > the gpiolib default limit to be twice the current. > > > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> > > --- > > Changes to previous version is that now we increase the common limit > > instead of adding x86 specific gpio.h > > Can you please include the reasoning for this decision in the > changeset description? I'm sure you have your reasons, but from > the text above, it sounds like a rather bad idea. What other > architectures are impacted by this, and what is the kernel size > cost for it on those architectures? How about, Current generic ARCH_NR_GPIOS limit is 256 which starts to be too small for newer Intel SoCs like Braswell. In order to support GPIO controllers on these SoCs we increase ARCH_NR_GPIOS to be 512 which should be sufficient for now. The kernel size increases a bit with this change. Below is an example of x86_64 kernel image. ARCH_NR_GPIOS=256 text data bss dec hex filename 11476173 1971328 1265664 14713165 e0814d vmlinux ARCH_NR_GPIOS=512 text data bss dec hex filename 11476173 1971328 1269760 14717261 e0914d vmlinux So the BSS size and this the kernel image size increases by 4k. -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Sep 15, 2014 at 4:09 PM, Mika Westerberg <mika.westerberg@linux.intel.com> wrote: > Some newer Intel SoCs, like Braswell already have more than 256 GPIOs > available so the default limit is exceeded. Instead of adding more > architecture specific gpio.h files with custom ARCH_NR_GPIOs we increase > the gpiolib default limit to be twice the current. > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Patch applied with the extended blurb in the commit message. Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h index c1d4105e1c1d..383ade1a211b 100644 --- a/include/asm-generic/gpio.h +++ b/include/asm-generic/gpio.h @@ -27,7 +27,7 @@ */ #ifndef ARCH_NR_GPIOS -#define ARCH_NR_GPIOS 256 +#define ARCH_NR_GPIOS 512 #endif /*
Some newer Intel SoCs, like Braswell already have more than 256 GPIOs available so the default limit is exceeded. Instead of adding more architecture specific gpio.h files with custom ARCH_NR_GPIOs we increase the gpiolib default limit to be twice the current. Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> --- Changes to previous version is that now we increase the common limit instead of adding x86 specific gpio.h include/asm-generic/gpio.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)