[PATCH] dmaengine: mv_xor_v2: Fix clock resource by adding a register clock

[Vinod Koul]

On Thu, Mar 01, 2018 at 09:37:03AM +0100, Gregory CLEMENT wrote:
> Hi Vinod,
>  
>  On jeu., mars 01 2018, Vinod Koul <vinod.koul at intel.com> wrote:
> 
> 
> >> >>  Optional properties:
> >> >> -- clocks: Optional reference to the clock used by the XOR engine.
> >> >> +- clocks: Optional reference to the clocks used by the XOR engine.
> >> >> +- clock-names: mandatory if there is a second clock, in this case the
> >> >> +   name must be "core" for the first clock and "reg" for the second
> >> >> +   one
> >> >> +
> >> >>  
> >> >>  Example:
> >> >>  
> >> >> diff --git a/drivers/dma/mv_xor_v2.c b/drivers/dma/mv_xor_v2.c
> >> >> index f652a0e0f5a2..93b3d80ce701 100644
> >> >> --- a/drivers/dma/mv_xor_v2.c
> >> >> +++ b/drivers/dma/mv_xor_v2.c
> >> >> @@ -163,6 +163,7 @@ struct mv_xor_v2_device {
> >> >>  	void __iomem *dma_base;
> >> >>  	void __iomem *glob_base;
> >> >>  	struct clk *clk;
> >> >> +	struct clk *reg_clk;
> >> >>  	struct tasklet_struct irq_tasklet;
> >> >>  	struct list_head free_sw_desc;
> >> >>  	struct dma_device dmadev;
> >> >> @@ -749,13 +750,24 @@ static int mv_xor_v2_probe(struct platform_device *pdev)
> >> >>  	if (ret)
> >> >>  		return ret;
> >> >>  
> >> >> -	xor_dev->clk = devm_clk_get(&pdev->dev, NULL);
> >> >> -	if (IS_ERR(xor_dev->clk) && PTR_ERR(xor_dev->clk) == -EPROBE_DEFER)
> >> >> +	xor_dev->reg_clk = devm_clk_get(&pdev->dev, "reg");
> >> >
> >> > is this an exiting property?
> >> 
> >> It is the name of the new optional clock described in the first part of
> >> this patch.
> >
> > okay I am missing something then, you are reading "reg" but property added is
> > "clock-names", where are you reading this?
> 
> "reg" is actually the _name_ of the clock given by the clock-names
> property.
> 
> With devm_clk_get the second parameter is a pointer to the name of the
> clock name. When it is NULL then, the first clock is used, else in the
> common clock framework looks for the clock associated with the name
> given.
> 
> With this patch both clock have now a name, but in order to be backward
> compatible, I don't use the name for the first clock. It allows to still
> use this clock with a device tree using the old binding.

Okay fine then, it might help to add this to changelog

> 
> Gregory
> 
> 
> >
> >> 
> >> About the typo, do you need a new version or do you plan to fix them
> >> while applying the patch?

please send an update

Thanks
-- 
~Vinod