Content-Type: text/plain; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Subject: [RFC,PATCH 0/2] Common struct clk implementation, v4
Message-Id: <1275636608.606606.450179637764.0.gpush@pororo>
To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Cc: Ben Herrenchmidt <benh@kernel.crashing.org>
From: Jeremy Kerr <jeremy.kerr@canonical.com>
Date: Fri, 04 Jun 2010 15:30:08 +0800
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 2268
Lines: 66

Hi all,

These patches are an attempt to allow platforms to share clock code. At
present, the definitions of 'struct clk' are local to platform code,
which makes allocating and initialising cross-platform clock sources
difficult, and makes it impossible to compile a single image containing
support for two ARM platforms with different struct clks.

The two patches are for the architecture-independent kernel code,
introducing the common clk infrastructure. The changelog for the first
patch includes details about the new clock definitions.

As requested by rmk, I've put together a small series of patches
illustrating the usage of the common struct clock on the ARM imx51
platform. These are available in my git tree:

 git://kernel.ubuntu.com/jk/dt/linux-2.6

in the clk-common-mx51 branch (clk-common..clk-common-mx51).

The approach I've taken with the imx51 port is to temporarly duplicate
the platform-common clock code (ie, for all mxc-based boards) to enable
usage of the common struct clk on one machine (imx51), while leaving the
others as-is. For a proper platform-wide usage of the common struct clk,
we'd be better off doing the whole platform at once. However, mx51 is
the only mxc-based HW I have, hence the duplicated example port.

In the example port, the first change simply converts the mxc's struct
clk to a struct clk_mxc, using the new API.  The subsequent patches move
certain clocks to more specific data structures (eg clk_fixed and
clk_pll) where possible.

Ben Herrenschmidt is looking at using common struct clk code for powerpc
too, hence the kernel-wide approach.

Comments most welcome.

Cheers,


Jeremy

--
v4:
 * use mutex for enable/disable locking
 * DEFINE_CLK -> INIT_CLK, and pass the clk name for mutex init
 * struct clk_operations -> struct clk_ops

v3:
 * do clock usage refcounting in common code
 * provide sample port

v2:
 * no longer ARM-specific
 * use clk_operations

---
Jeremy Kerr (2):
      Add a common struct clk
      clk: Generic support for fixed-rate clocks

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/