Re: [Patch v6 2/2] dmaengine: add Qualcomm BAM dma driver

From: Andy Gross
Date: Fri Feb 21 2014 - 12:22:20 EST


On Fri, Feb 21, 2014 at 09:33:52AM +0000, Mark Rutland wrote:
> On Fri, Feb 21, 2014 at 06:43:05AM +0000, Andy Gross wrote:

[snip]
> > + bdev->bamclk = devm_clk_get(bdev->dev, "bam_clk");
>
> The binding document should describe the "bam_clk" string in the
> clock-names description.
>

OK.

> > + ret = of_property_read_u32(pdev->dev.of_node, "qcom,ee", &bdev->ee);
> > + if (ret) {
> > + dev_err(bdev->dev, "EE unspecified\n");
>
> It would be nice to expand EE to what it stands for, at least in the
> error but possibly the binding too.

I can expand it to execution environment. This is a trustzone thing and is
required from a security perspective.

> > +static const struct of_device_id bam_of_match[] = {
> > + { .compatible = "qcom,bam-v1.4.0", },
> > + { .compatible = "qcom,bam-v1.4.1", },
>
> What are the differences between the two?
>
> Is v1.4.1 an extension of v1.4.0?

On second look, the 1.4.1 has hardware fixes. So the software API is the same.
I thought there were some configuration changes, but that isn't the case.

> Could you have the following in DTs:
>
> compatible = "qcom,bam-v1.4.1", "qcom,bam-v1.4.0";
>
> Then you'd only need the v1.4.0 string in the driver for now.

Good point. That's easy to change.

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