From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <bb38a5f71217f84cb29b01eb6ceede4c@hamnavoe.com>
To: 9fans@9fans.net
From: Richard Miller <9fans@hamnavoe.com>
Date: Tue, 29 Dec 2015 10:55:30 +0000
In-Reply-To: <1211924935.3518360.1451362224733.JavaMail.yahoo@mail.yahoo.com>
MIME-Version: 1.0
Content-Type: text/plain; charset="US-ASCII"
Content-Transfer-Encoding: 7bit
Subject: Re: [9fans] Pi updates
Topicbox-Message-UUID: 7b2913a2-ead9-11e9-9d60-3106f5b1d025

Thanks, Brian - that all looks very useful to make the pi more amenable
to hardware tinkering.

One small suggested amendment: your spiclock() says this -

/*
 * According the Broadcom docs, the divisor has to
 * be a power of 2.  This code rounds up so that the
 * resulting clock is the highest value no greater than
 * what's requested.
 */

but http://raspberrypi.org/documentation/hardware/raspberrypi/spi/README.md
has an erratum suggesting "power of 2" should be "multiple of 2".  I have
been using a default divisor of 250 for a 1MHz clock, and that's the frequency
I see on my oscilloscope.