Re: [RFC 17/17] clk: zynq: remove call to of_clk_init

From: Steffen Trumtrar <s.trumtrar@pengutronix.de>
To: "Sören Brinkmann" <soren.brinkmann@xilinx.com>
Cc: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>,
	Michal Simek <monstr@monstr.eu>,
	Russell King <linux@arm.linux.org.uk>,
	Arnd Bergmann <arnd@arndb.de>,
	Michal Simek <michal.simek@xilinx.com>,
	linux-kernel@vger.kernel.org,
	Mike Turquette <mturquette@linaro.org>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC 17/17] clk: zynq: remove call to of_clk_init
Date: Mon, 26 Aug 2013 17:33:29 +0200	[thread overview]
Message-ID: <20130826153329.GE24795@pengutronix.de> (raw)
In-Reply-To: <c46b466a-1f8a-4b22-9dad-9d2419100b06@TX2EHSMHS043.ehs.local>

On Mon, Aug 26, 2013 at 08:16:29AM -0700, Sören Brinkmann wrote:
> On Mon, Aug 26, 2013 at 02:53:35PM +0200, Sebastian Hesselbarth wrote:
> > On 08/26/13 14:07, Steffen Trumtrar wrote:
> > >On Mon, Aug 26, 2013 at 01:15:11PM +0200, Michal Simek wrote:
> > >>I agree with Soren - let's fix the current problem and then when Steffen has patches with syscon
> > >>we can look at them.
> > >>
> > >>If there is any discussion about early syscon registration please let me know.
> > >>
> > >
> > >Where I'm stuck at the moment is: if I map the whole register space to the
> > >parent node, how do I get its mapped address in the clkc?
> > 
> > Steffen,
> > 
> > if slcr is such an essential part of the SoC, you can choose to provide
> > zynq_slcr_readl/writel callbacks. You can then use those callback in the
> > clock driver without knowing the base address. Also, it allows you to
> > hide slcr specific locking details from subsequent drivers using the
> > callbacks.
> 
> I don't think that'll work. The clkc just wraps the cock primitives and
> does not provide a lot of own clock drivers - actually only one. Those
> clock primitives receive an iomapped address for the clock control which
> is then accessed using readl/writel(). So, wrapping all SLCR accesses in
> special accessors would mean to have almost identical reimplementations
> of all used clock primitives, just to replace readl/writel with
> zynq_slcr_write/read. Or is there some way to make this actually work?

This is exactly my understanding, why I can't use a callback here. At least
not for the clkc.

str

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