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References: <20200922023151.387447-1-warthog618@gmail.com> <20200922023151.387447-12-warthog618@gmail.com>
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From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Wed, 23 Sep 2020 19:18:08 +0300
Message-ID: <CAHp75Vd6tb09n+okJmoPse992DeoPkJQHReNBo20FQNz1V2c5w@mail.gmail.com>
Subject: Re: [PATCH v9 11/20] gpiolib: cdev: support GPIO_V2_LINE_SET_VALUES_IOCTL
To:     Kent Gibson <warthog618@gmail.com>
Cc:     Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
        Bartosz Golaszewski <bgolaszewski@baylibre.com>,
        Linus Walleij <linus.walleij@linaro.org>,
        Arnd Bergmann <arnd@arndb.de>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Tue, Sep 22, 2020 at 5:36 AM Kent Gibson <warthog618@gmail.com> wrote:
>
> Add support for the GPIO_V2_LINE_SET_VALUES_IOCTL.

> +static long linereq_set_values_unlocked(struct linereq *lr,
> +                                       struct gpio_v2_line_values *lv)
> +{
> +       DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
> +       struct gpio_desc **descs;
> +       unsigned int i, didx, num_set;
> +       int ret;
> +
> +       bitmap_zero(vals, GPIO_V2_LINES_MAX);
> +       for (num_set = 0, i = 0; i < lr->num_lines; i++) {
> +               if (lv->mask & BIT_ULL(i)) {

Similar idea

DECLARE_BITMAP(mask, 64) = BITMAP_FROM_U64(lv->mask);

num_set = bitmap_weight();

for_each_set_bit(i, mask, lr->num_lines)


> +                       if (!test_bit(FLAG_IS_OUT, &lr->lines[i].desc->flags))
> +                               return -EPERM;
> +                       if (lv->bits & BIT_ULL(i))
> +                               __set_bit(num_set, vals);
> +                       num_set++;
> +                       descs = &lr->lines[i].desc;
> +               }
> +       }
> +       if (num_set == 0)
> +               return -EINVAL;
> +
> +       if (num_set != 1) {
> +               /* build compacted desc array and values */
> +               descs = kmalloc_array(num_set, sizeof(*descs), GFP_KERNEL);
> +               if (!descs)
> +                       return -ENOMEM;
> +               for (didx = 0, i = 0; i < lr->num_lines; i++) {
> +                       if (lv->mask & BIT_ULL(i)) {
> +                               descs[didx] = lr->lines[i].desc;
> +                               didx++;
> +                       }
> +               }
> +       }
> +       ret = gpiod_set_array_value_complex(false, true, num_set,
> +                                           descs, NULL, vals);
> +
> +       if (num_set != 1)
> +               kfree(descs);
> +       return ret;
> +}
> +
> +static long linereq_set_values(struct linereq *lr, void __user *ip)
> +{
> +       struct gpio_v2_line_values lv;
> +       int ret;
> +
> +       if (copy_from_user(&lv, ip, sizeof(lv)))
> +               return -EFAULT;
> +
> +       mutex_lock(&lr->config_mutex);
> +
> +       ret = linereq_set_values_unlocked(lr, &lv);
> +
> +       mutex_unlock(&lr->config_mutex);
> +
> +       return ret;
> +}
> +
>  static long linereq_set_config_unlocked(struct linereq *lr,
>                                         struct gpio_v2_line_config *lc)
>  {
> @@ -889,6 +948,8 @@ static long linereq_ioctl(struct file *file, unsigned int cmd,
>
>         if (cmd == GPIO_V2_LINE_GET_VALUES_IOCTL)
>                 return linereq_get_values(lr, ip);
> +       else if (cmd == GPIO_V2_LINE_SET_VALUES_IOCTL)
> +               return linereq_set_values(lr, ip);
>         else if (cmd == GPIO_V2_LINE_SET_CONFIG_IOCTL)
>                 return linereq_set_config(lr, ip);
>
> --
> 2.28.0
>


-- 
With Best Regards,
Andy Shevchenko