[PATCH linux dev-4.10] aspeed: Set max gpio num.

Milton Miller II miltonm at us.ibm.com
Fri Jun 30 10:34:55 AEST 2017

On June 29 2017 at 8:31 in some time zone, Mykola Kostenok wrote:
>Set maximum number of gpio for ARCH_ASPEED.
>Signed-off-by: Mykola Kostenok <c_mykolak at mellanox.com>

>diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
>index 186c4c214e0a..9d373685c628 100644
>--- a/arch/arm/Kconfig
>+++ b/arch/arm/Kconfig
>@@ -1492,6 +1492,7 @@ config ARCH_NR_GPIO
> 	default 352 if ARCH_VT8500
> 	default 288 if ARCH_ROCKCHIP
> 	default 264 if MACH_H4700
>+	default 232 if ARCH_ASPEED
> 	default 0
> 	help
> 	  Maximum number of GPIOs in the system.

This is a bad idea.  This sets the maximum total number 
of gpios supported by the kernel, and setting it to this 
value would not allow any space for the various pca 
expanders to define additional gpios.

The logic in asm-generic/gpio.h says if the CONFIG 
number is 0 use 512 else use the supplied value.

I'm guessing this was motivated to make the gpio numbers 
match with the controller.  Unfortunately the gpios from 
the device tree are assigned numbers from the end of 
the number space.

If we need to assign a specific range, we should try 
to define an optional property in the gpio chip binding 
and assign the value to gpio-chip.base in gpio-aspeed.c, 
but I am doubtful that such a patch would be accepted 


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