linux-kernel - Re: [PATCH 3/3] i2c:ocores: add polling interface

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Message-ID: <5709014.JH4KZFlPMP@pcbe13614>
Date:   Mon, 29 Oct 2018 14:11:14 +0100
From:   Federico Vaga <federico.vaga@...n.ch>
To:     Peter Korsgaard <peter@...sgaard.com>,
        linux-i2c <linux-i2c@...r.kernel.org>
CC:     <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/3] i2c:ocores: add polling interface

On Monday, October 29, 2018 2:04:13 PM CET Peter Korsgaard wrote:
>  > I think that something like this could be better
>  > 
>  > (2) usleep_range(sleep_min, sleep_min * XXX);
>  > 
>  > But.
>  > Since it is better to make this patch ready for xfer_irqless, then I will
>  > definitively go for udelay(). The reason is that, xfer_irqless may run in
>  > atomic context where we can't sleep at all.
> 
> Great! BTW I noticed that your sleep_min calculation looked odd:
> 
> int sleep_min = (8/i2c->bus_clock_khz) * 1000; /* us for 8bits
> 
> bus_clock_khz almost certainly will be bigger than 8 (E.G. likely
> 100KHz), so the above set sleep_min to 0. Please move the * 1000 before
> the division.

True, oops