Re: [PATCH 2/9] mtd: pxa3xx_nand: add a non mandatory ECC clock

Antoine Tenart
2015-01-28T20:13:18Z

Hi Andrew,

On Tue, Jan 27, 2015 at 04:50:47PM +0100, Andrew Lunn wrote:
> On Tue, Jan 27, 2015 at 03:10:09PM +0100, Antoine Tenart wrote:
> > Some controllers (as the coming Berlin nand controller) need to enable
> > an ECC clock. Add support for this clock in the pxa3xx nand driver, and
> > leave it as non mandatory.
>
> It would be good to document this clock in the device tree binding.

Yes! I'll add the ECC clock into the documentation.

>
> > Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
> > ---
> > drivers/mtd/nand/pxa3xx_nand.c | 26 +++++++++++++++++++-------
> > 1 file changed, 19 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/mtd/nand/pxa3xx_nand.c b/drivers/mtd/nand/pxa3xx_nand.c
> > index d00ac392d1c4..2681ec4abafa 100644
> > --- a/drivers/mtd/nand/pxa3xx_nand.c
> > +++ b/drivers/mtd/nand/pxa3xx_nand.c
> > @@ -180,7 +180,7 @@ struct pxa3xx_nand_info {
> > struct nand_hw_control controller;
> > struct platform_device *pdev;
> >
> > - struct clk *clk;
> > + struct clk *clk, *ecc_clk;
> > void __iomem *mmio_base;
> > unsigned long mmio_phys;
> > struct completion cmd_complete, dev_ready;
> > @@ -1608,7 +1608,7 @@ static int alloc_nand_resource(struct platform_device *pdev)
> >
> > spin_lock_init(&chip->controller->lock);
> > init_waitqueue_head(&chip->controller->wq);
> > - info->clk = devm_clk_get(&pdev->dev, NULL);
> > + info->clk = devm_clk_get(&pdev->dev, "nfc");
>
> Does this keep backwards compatibility? Not all the existing users
> have there clocks named. What i think happens here is that
> of_clk_get_by_name() calls of_property_match_string(np, "clock-names",
> name); That returns -EINVAL, and then we ask of_clk_get() to get the
> -EINVAL'th clock. I don't think that is going to end well.
>
> I think you need to keep the NULL here, but should use "ecc" for the
> second clock and require the use of the clock-names property when an
> ecc clock is required.

I agree, I'll go back to NULL in v2.

Antoine

--
Antoine Ténart, Free Electrons
Embedded Linux, Kernel and Android engineering