[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.
Regards,
--Hongwei
> 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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