Messages in this thread | | | Subject | [PATCH 0/2] Common struct clk implementation, v8 | From | Jeremy Kerr <> | Date | Wed, 08 Dec 2010 10:08:14 +0800 |
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[apologies for the resend: missed this series description]
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). There is also a port for versatile (clk-common-versatile) in this tree too.
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.
Many thanks to the following for their input: * Ben Dooks <ben-linux@fluff.org> * Baruch Siach <baruch@tkos.co.il> * Russell King <linux@arm.linux.org.uk> * Uwe Kleine-König <u.kleine-koenig@pengutronix.de> * Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com> * Vincent Guittot <vincent.guittot@linaro.org>
Russell - now that we've had a few platforms ported to the common clk infrastructure, I believe it's ready to merge. If so, do you want this in the patch tracker? Otherwise, let me know what needs changing.
Cheers,
Jeremy
-- v8: * add atomic clocks, and locking wrappers * expand comments on clk and clk_ops
v7: * change CLK_INIT to initialise clk->mutex statically
v6: * fixed up references to 'clk_operations' in the changelog
v5: * uninline main API, and share definitions with !USE_COMMON_STRUCT_CLK * add __clk_get * delay mutex init * kerneldoc for struct clk
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
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