linux-kernel - Re: [PATCH 05/11] spi/pxa2xx: make clock rate configurable from platform data

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]

Message-ID: <20130108124153.GJ13897@intel.com>
Date:	Tue, 8 Jan 2013 14:41:53 +0200
From:	Mika Westerberg <mika.westerberg@...ux.intel.com>
To:	Mark Brown <broonie@...nsource.wolfsonmicro.com>
Cc:	linux-kernel@...r.kernel.org, grant.likely@...retlab.ca,
	linus.walleij@...aro.org, eric.y.miao@...il.com,
	linux@....linux.org.uk, haojian.zhuang@...il.com,
	chao.bi@...el.com, "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>
Subject: Re: [PATCH 05/11] spi/pxa2xx: make clock rate configurable from
 platform data

On Tue, Jan 08, 2013 at 11:02:28AM +0000, Mark Brown wrote:
> On Mon, Jan 07, 2013 at 12:44:34PM +0200, Mika Westerberg wrote:
> > If the architecture doesn't support clk framework (like x86) we need a way to
> > pass the SSP clock rate to the driver. This patch adds a field in the platform
> > data 'fixed_clk_rate' that allows passing the rate.
> 
> No, the way to do this is to fix x86 to enable the clock API there.  The
> x86 maintainers couldn't be bothered when I submitted a patch and
> getting anyone to take a patch to make it available by default appears
> to be unreasonably hard but perhaps if someone from Intel tries the x86
> maintainers might take a patch...

Do you mean enabling CONFIG_COMMON_CLK on x86?

> We shouldn't be adding special case code to every driver that might need
> a clock that gets used on an Intel system.

I agree and it is cleaner to have the same API for all arches. However, I'm
not sure how do we create the fixed clocks then? There is nothing in ACPI
namespace (or in the ACPI 5.0 spec) that allows you to describe clocks and
their relationships.

So then we end up either:

	1. Creating a custom board file for Lynxpoint which creates the
	   clocks. This is something I think x86 maintainers don't want to
	   see.

	2. Creating the clock in the driver itself in its ACPI enumeration
	   implementation. This might work but it litters the drivers with
	   clock details.

Or is there something I'm missing?
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/