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Subject: Re: [PATCH v8 1/2] spi: Add Renesas R-Car Gen3 RPC-IF SPI controller
 driver
To:     masonccyang@mxic.com.tw
Cc:     bbrezillon@kernel.org, broonie@kernel.org,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        Simon Horman <horms@verge.net.au>, juliensu@mxic.com.tw,
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        linux-spi@vger.kernel.org, marek.vasut@gmail.com,
        zhengxunli@mxic.com.tw
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From:   Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Organization: Cogent Embedded
Message-ID: <2fa6af66-de08-be37-7cdf-ccbf1e50ceb0@cogentembedded.com>
Date:   Mon, 25 Mar 2019 22:12:10 +0300
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Hello!

On 03/25/2019 11:28 AM, masonccyang@mxic.com.tw wrote:

>> > +static void rpc_spi_mem_set_prep_op_cfg(struct spi_device *spi,
>> > +               const struct spi_mem_op *op,
>> > +               u64 *offs, size_t *len)
>> > +{
>> > +   struct rpc_spi *rpc = spi_controller_get_devdata(spi->controller);
>>
>> > +   if (op->dummy.nbytes) {
>> > +      rpc->smenr |= RPC_SMENR_DME;
>> > +      rpc->dummy = RPC_SMDMCR_DMCYC(op->dummy.nbytes);
>>
>>    SMDMCR.DMCYC is in bits -- you forgot to multiply by 8.
> 
> ?
> 
> It's dummy cycles setting, i.e,. 0 is 1 cycle dummy and

   Yeah, I should've written "cycles", sorry about that.

> max is 0x13 for 20 cycle dummy, depends on transfer bit size setting = 1, 4 or 8.
> right ?

   Probably...

[...]

MBR, Sergei