linux-kernel - Re: [PATCH] staging: fbtft: Replace mdelay() with msleep() and usleep

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Message-ID: <CAHp75VdMQ2Cx+0cH8PuM8t8i2NgphxEqU4g86y5Hgwi1_CQ9zQ@mail.gmail.com>
Date:   Fri, 27 Jul 2018 13:34:48 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Jia-Ju Bai <baijiaju1990@...il.com>
Cc:     Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        devel@...verdev.osuosl.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] staging: fbtft: Replace mdelay() with msleep() and usleep_range()

On Fri, Jul 27, 2018 at 12:21 PM, Jia-Ju Bai <baijiaju1990@...il.com> wrote:
> reset() and init_display() are never called in atomic context.
> They call mdelay() to busily wait, which is not necessary.
> mdelay() can be replaced with msleep().

>         gpio_set_value(par->gpio.reset, 0);
>         udelay(20);
>         gpio_set_value(par->gpio.reset, 1);
> -       mdelay(120);
> +       msleep(120);

I didn't look to the rest, but this one will be inconsistent after your patch.

The question here is why udelay() is needed, while mdelay() changed?

-- 
With Best Regards,
Andy Shevchenko