[v6 2/2] gpio: aspeed: Add SGPIO driver

Hongwei Zhang hongweiz at ami.com
Tue Jul 30 06:43:46 AEST 2019

Hello Linus,

Thanks for your detailed comments.

We just submitted a v6 of sgpio-aspeed.c, it includes the updates based on
your initial feedback:

1. fix a bug in aspeed_sgpio_dir_out()
2. some comments clean up.


> From:	Linus Walleij <linus.walleij at linaro.org>
> Sent:	Sunday, July 28, 2019 7:38 PM
> To:	Hongwei Zhang
> Cc:	Andrew Jeffery; linux-gpio; Joel Stanley; linux-aspeed; Bartosz Golaszewski; linux-kernel; linux-
> arm-kernel
> Subject:	Re: [v5 2/2] gpio: aspeed: Add SGPIO driver
> On Mon, Jul 22, 2019 at 10:37 PM Hongwei Zhang <hongweiz at ami.com> wrote:
> > As you suspected it correctly, AST2500 utilizes all the 32 bits of the 
> > registers (data value, interrupt, etc...), such that using 8-bit bands 
> > [7:0]/[15:8]/23:16]/[31:24] of GPIO_200H for SGPIO_A/B/C/D .
> > so registering 10 gpiochip drivers separately will make code more 
> > complicated, for example gpio_200 register (data_value reg) has to be 
> > shared by 4 gpiochip instances, and the same is true for gpio204 
> > (interrupt reg), and other more registers.
> > So we would prefer to keeping current implementation.
> OK this is a pretty good argument. My review assumed one 32-bit register was not shared between 
> banks but it is, I see.
> The above situation can be managed by regmap, but that will just a different complexity so go with this 
> approach then.
> Yours,
> Linus Walleij

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