linux-kernel - Re: [PATCH 4/4] spi: bcm-mspi: Add support to set serial baud clock rate

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 6 Apr 2015 10:46:36 +0100
From:	Mark Brown <broonie@...nel.org>
To:	Florian Fainelli <f.fainelli@...il.com>
Cc:	Jonathan Richardson <jonathar@...adcom.com>,
	Dmitry Torokhov <dtor@...gle.com>,
	Anatol Pomazau <anatol@...gle.com>,
	Scott Branden <sbranden@...adcom.com>,
	Rob Herring <robh+dt@...nel.org>,
	Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	linux-kernel@...r.kernel.org, linux-spi@...r.kernel.org,
	bcm-kernel-feedback-list <bcm-kernel-feedback-list@...adcom.com>,
	devicetree@...r.kernel.org, Rafal Milecki <zajec5@...il.com>,
	Brian Norris <computersforpeace@...il.com>,
	Kevin Cernekee <cernekee@...il.com>
Subject: Re: [PATCH 4/4] spi: bcm-mspi: Add support to set serial baud clock
 rate

On Sat, Apr 04, 2015 at 12:12:59PM -0700, Florian Fainelli wrote:
> Le 02/04/2015 12:23, Jonathan Richardson a écrit :

> > +		/* Calculate SPBR if clock-frequency provided. */
> > +		if (of_property_read_u32(dev->of_node, "clock-frequency",
> > +			&desired_rate) >= 0) {
> > +			u32 spbr = clk_get_rate(data->clk) / (2 * desired_rate);

> Usually, specifying a "clock-frequency" property is done when there is
> no clock provider available, yet we take this code path only if we could
> find a "mspi_clk" which sounds a litle weird.

> Once there is a proper "mspi_clk" clock, I would make it mandatory for
> the clock provider to be able to provide the rate as well?

As far as I can tell it's already mandatory if the property is present -
it's taking the clock presented to the block and then using an internal
divider to bring that down to the desired rate.

We are missing error handling though.

Download attachment "signature.asc" of type "application/pgp-signature" (474 bytes)