[RFC 09/14] MV SATA: Add per channel clk/clkdev support.

[andrew@lunn.ch (Andrew Lunn)]

On Wed, Mar 07, 2012 at 08:11:37AM -0500, Jason wrote:
> On Wed, Mar 07, 2012 at 07:38:58AM +0100, Andrew Lunn wrote:
> > > Date: Tue, 6 Mar 2012 14:01:39 -0500
> > > From: Jason <jason@lakedaemon.net>
> > > To: Andrew Lunn <andrew@lunn.ch>
> > > Cc: linux-arm-kernel at lists.infradead.org
> > > Subject: Re: [RFC 09/14] MV SATA: Add per channel clk/clkdev support.
> > > Message-ID: <20120306190139.GW5050@titan.lakedaemon.net>
> > > Content-Type: text/plain; charset=us-ascii
> > > 
> > > On Tue, Mar 06, 2012 at 07:31:05AM +0100, Andrew Lunn wrote:
> > > > The Orion kirkwood chips have a gatable clock per SATA channel. Add
> > > 
> > > +mv_sata_platform_data *sata_data)
> > > >       if (sata_data->n_ports > 1)
> > > >               kirkwood_clk_ctrl |= CGC_SATA1;
> > > >
> > > > +     orion_clkdev_add("0", "sata_mv.0", &clk_sata0);
> > > > +     orion_clkdev_add("1", "sata_mv.0", &clk_sata1);
> > > > +
> > > 
> > > This is a problem for devicetree.  With devicetree, neither
> > > kirkwood_sata_init(), nor orion_sata_init() are ever called.  The same
> > > is true for all the other drivers as well.
> > > 
> > > Could this be moved into the driver's _probe() function?
> > 
> > No, this cannot be in the driver. This is setting up the mapping
> > between the device name and the clk the device should use. dove,
> > orion5x, mv78xx0 need a different clk to kirkwood and this is hidden
> > by clkdev, so the driver does not have to care.
> 
> Thanks for the clarification.
> 
> > BTW: Not all drivers which orion uses are only used by orion. So we
> > have to be careful not to add orion specific stuff into some of the
> > drivers. This is particularly true for Ethernet and SATA.
> > 
> > There are two possible solutions to clkdev:
> > 
> > 1) Add DT bindings for clkdev. I don't know if this is currently
> >    supported?
> 
> I came to the same conclusion late last night and started poking around.
> I didn't see it in any of Mike's patches.

You are missing up clk and clkdev. Mike's patches are for clk. You
need clkdev bindings.

> > 2) I can refactor the code. Currently i create the clkdev entries on
> >    demand. However i could just create them all just after creating
> >    the clocks.

> drivers/clk/of_clk.c ?  I'll start looking at it.

drivers/clk/of_clkdev.c, or maybe drivers/of/of_clkdev.c. You should
probably run this by Grant before investing too much effort. It might
be a stupid idea...

Also, most of the refactoring is done. Needs some testing and then i
can send RFCv2 patches.

    Andrew