Re: [PATCH] gpio: dwapb: Add support for next generation of X-Gene SoC

[Hoan Tran <hotran@xxxxxxx>]

Resend with plain text.

Hi Linus,


On Mon, Feb 6, 2017 at 2:21 AM, Linus Walleij <linus.walleij@xxxxxxxxxx> wrote:
> On Tue, Jan 31, 2017 at 8:43 PM, Hoan Tran <hotran@xxxxxxx> wrote:
>
>> Next generation of X-Gene SoC's GPIO hardware register map is very
>> similar to DW GPIO. It only differs by a few register addresses.
>> This patch modifies DW GPIO driver to accommodate the difference
>> in a few register addresses.
>>
>> Signed-off-by: Hoan Tran <hotran@xxxxxxx>
>
> On next iteration please include Jamie Iles, Weike Chen and Sebastian
> Andrzej Siewior.
> They all provided substantial contributions to this driver.
>
> The dwapb needs a proper maintainer in MAINTAINERS actually, it is one of
> those that can't use GPIOLIB_IRQCHIP so it requires special attention.
> Jamie, interested in the job? Patches welcome :)
>
> Also I've been thinking about this:
>
> #define GPIO_SWPORTA_DR         0x00
> #define GPIO_SWPORTA_DDR        0x04
> #define GPIO_SWPORTB_DR         0x0c
> #define GPIO_SWPORTB_DDR        0x10
> #define GPIO_SWPORTC_DR         0x18
> #define GPIO_SWPORTC_DDR        0x1c
> #define GPIO_SWPORTD_DR         0x24
> #define GPIO_SWPORTD_DDR        0x28
> #define GPIO_INTEN              0x30
> #define GPIO_INTMASK            0x34
> #define GPIO_INTTYPE_LEVEL      0x38
> #define GPIO_INT_POLARITY       0x3c
> #define GPIO_INTSTATUS          0x40
> #define GPIO_PORTA_DEBOUNCE     0x48
> #define GPIO_PORTA_EOI          0x4c
> #define GPIO_EXT_PORTA          0x50
> #define GPIO_EXT_PORTB          0x54
> #define GPIO_EXT_PORTC          0x58
> #define GPIO_EXT_PORTD          0x5c
>
> I wonder what is at addresses 0x08, 0x14, 0x20, 0x2c, 0x44?

They are unused registers.
 - 0x8, 0x14, 0x20, 0x2c are port data source registers.
 - 0x44 is the raw interrupt status register.


>
> Anything interesting we should know about? I bet they are not just
> dead address space.
>
> Is there a public datasheet for this thing that I can look at?

I don't know if they public this datasheet. You can register and
download from here
https://www.synopsys.com/dw/ipdir.php?c=DW_apb_gpio

Thanks
Hoan

>
> Yours,
> Linus Walleij
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