From: arnd@arndb•de (Arnd Bergmann)
To: linux-arm-kernel@lists•infradead.org
Subject: PXA 2xx devictree port and clock infrastructure
Date: Tue, 27 May 2014 17:17:48 +0200 [thread overview]
Message-ID: <201405271717.48783.arnd@arndb.de> (raw)
In-Reply-To: <87zji3cr3d.fsf@free.fr>
On Tuesday 27 May 2014, Robert Jarzmik wrote:
> I'm playing with devicetree to port the mioa701 machine code to devicetree (or
> rather to eliminate the mioa701 machine code).
>
> While porting the pxa2xx device drivers, I came to a question about the clock
> infrastructure, and I'd need a bit of guidance.
>
> Many drivers, in their probe code are doing something like :
> 1) regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> 2) irq = platform_get_irq(pdev, 0);
> 3) clk = clk_get(&pdev->dev, NULL);
>
> Points 1 and 2 are straightforward with DT. Point 3 is not so obvious to me.
>
> As there is no platform data anymore, the clock infrastructure wants to match
> the OF device (in my case udc at 40600000) with the registered
> clocks. Unfortunately, the registered clock is named "pxa27x-udc", which works
> well in "platform data" devices, but not in devicetree populated devices.
>
> Therefore, I'd like to know what to do, and an example in another platform would
> be great. Should I create a clkdev driver in drivers/clk, or is there another
> ... faster way ? And Daniel, you probably solved it already for
> arch/arm/mach-pxa/pxa-dt.c, didn't you ?
There are generally three ways of doing this:
a) use an auxdata table to reassign the device names to what they
used to be
b) change the clkdev lookup to also include the new names (e.g. "40600000.udc")
c) write a DT-aware clock driver and list all clocks in DT
Arnd
next prev parent reply other threads:[~2014-05-27 15:17 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-27 13:02 PXA 2xx devictree port and clock infrastructure Robert Jarzmik
2014-05-27 15:17 ` Arnd Bergmann [this message]
2014-05-27 15:43 ` Mark Rutland
2014-05-27 15:49 ` Arnd Bergmann
2014-05-27 23:20 ` Robert Jarzmik
2014-05-28 1:05 ` Mike Turquette
2014-06-05 3:01 ` Andrew Ruder
2014-06-07 18:49 ` Robert Jarzmik
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