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SubjectRe: [PATCH 06/14] dmaengine: dma-jz4780: Add support for the JZ4725B SoC
On 10-07-18, 17:45, Paul Cercueil wrote:
>
>
> Le lun. 9 juil. 2018 à 19:14, Vinod <vkoul@kernel.org> a écrit :
> > On 03-07-18, 14:32, Paul Cercueil wrote:
> > > The JZ4725B has one DMA core starring six DMA channels.
> > > As for the JZ4770, each DMA channel's clock can be enabled with
> > > a register write, the difference here being that once started, it
> > > is not possible to turn it off.
> >
> > ok so disable for this, right..
> >
> > > @@ -204,6 +205,8 @@ static inline void
> > > jz4780_dma_chan_enable(struct jz4780_dma_dev *jzdma,
> > > {
> > > if (jzdma->version == ID_JZ4770)
> > > jz4780_dma_ctrl_writel(jzdma, JZ_DMA_REG_DCKES, BIT(chn));
> > > + else if (jzdma->version == ID_JZ4725B)
> > > + jz4780_dma_ctrl_writel(jzdma, JZ_DMA_REG_DCKE, BIT(chn));
> >
> > but you are writing to a different register here..
>
> Yes. SoCs >= JZ4770 have the DCKE read-only register, and DCKES/DCKEC to
> set/clear bits in DCKE.
> On JZ4725B, DCKE is read/write, but the zeros written are ignored (at least
> that's what the
> documentation says).

and that was not documented in the log... so i though it maybe a typo.

--
~Vinod

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