Re: [PATCH 3/6] gpio: add a userspace chardev ABI for GPIOs

[Bamvor Zhang Jian <bamvor.zhangjian@xxxxxxxxxx>]

Hi, Linus

On 10/22/2015 04:32 PM, Linus Walleij wrote:
> A new chardev that is to be used for userspace GPIO access is
[...]
> diff --git a/include/uapi/linux/gpio.h b/include/uapi/linux/gpio.h
> new file mode 100644
> index 000000000000..3188a87bdaa0
> --- /dev/null
> +++ b/include/uapi/linux/gpio.h
> @@ -0,0 +1,28 @@
> +/*
> + * <linux/gpio.h> - userspace ABI for the GPIO character devices
> + *
> + * Copyright (C) 2015 Linus Walleij
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License version 2 as published by
> + * the Free Software Foundation.
> + */
> +#ifndef _UAPI_GPIO_H_
> +#define _UAPI_GPIO_H_
> +
> +#include <linux/ioctl.h>
> +#include <linux/types.h>
> +
> +/**
> + * struct gpiochip_info - Information about a certain GPIO chip
> + * @name: the name of this GPIO chip
> + * @lines: number of GPIO lines on this chip
> + */
> +struct gpiochip_info {
> + char name[32];
> + __u32 lines;
> +};
> +
> +#define GPIO_GET_CHIPINFO_IOCTL _IOR('o', 0x01, struct gpiochip_info)

I am trying to use this interface to do my gpio mockup test. I need to list
all the gpiochips attach to one gpio driver(aka gpio-mockup, there may
be more than one gpio drivers in the system). And then test some of the
pin of each gpio_chip.

>From the api(ioctl GPIO_GET_CHIPINFO_IOCTL: gpiochip_info), it seems
that I could list all the gpiochips or list only one gpiochip. But
I could not list gpiochip belongs to one gpio driver.

Do I understand correctly?
Will we add a new api to do it?

Regards

Bamvor

> +
> +#endif /* _UAPI_GPIO_H_ */
>
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