linux-kernel - Re: [RFT PATCH 6/7] gpio: exar: switch to using regmap

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Date:   Wed, 4 Nov 2020 17:32:46 +0100
From:   Bartosz Golaszewski <brgl@...ev.pl>
To:     Sudip Mukherjee <sudipm.mukherjee@...il.com>,
        Linus Walleij <linus.walleij@...aro.org>
Cc:     "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>
Subject: Re: [RFT PATCH 6/7] gpio: exar: switch to using regmap

On Mon, Oct 26, 2020 at 3:18 PM Bartosz Golaszewski <brgl@...ev.pl> wrote:
>
> From: Bartosz Golaszewski <bgolaszewski@...libre.com>
>
> We can simplify the code in gpio-exar by using regmap. This allows us to
> drop the mutex (regmap provides its own locking) and we can also reuse
> regmap's bit operations instead of implementing our own update function.
>
> Signed-off-by: Bartosz Golaszewski <bgolaszewski@...libre.com>

[snip]

>
>  static int exar_direction_output(struct gpio_chip *chip, unsigned int offset,
>                                  int value)
>  {
> -       exar_set_value(chip, offset, value);
> -       return exar_set_direction(chip, 0, offset);
> +       struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
> +       unsigned int addr = exar_offset_to_sel_addr(exar_gpio, offset);
> +       unsigned int bit = exar_offset_to_bit(exar_gpio, offset);
> +
> +       regmap_clear_bits(exar_gpio->regs, addr, BIT(bit));
> +
> +       return 0;
>  }
>

Upon closer look I noticed this now ignores the value argument. I
doubt however it's the culprit of the crash Jan reported.

[snip]

Bartosz