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Message-ID: <915d772b-616b-9f2e-8f4e-16d9d349e0cf@gmail.com>
Date: Thu, 6 Dec 2018 10:14:17 +0100
From: Marek Vasut <marek.vasut@...il.com>
To: Geert Uytterhoeven <geert@...ux-m68k.org>, masonccyang@...c.com.tw
Cc: Boris Brezillon <boris.brezillon@...tlin.com>,
Mark Brown <broonie@...nel.org>,
Geert Uytterhoeven <geert+renesas@...der.be>,
Simon Horman <horms@...ge.net.au>, juliensu@...c.com.tw,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Linux-Renesas <linux-renesas-soc@...r.kernel.org>,
linux-spi <linux-spi@...r.kernel.org>, zhengxunli@...c.com.tw
Subject: Re: [PATCH v2 1/2] spi: Add Renesas R-Car Gen3 RPC SPI controller
driver
On 12/06/2018 10:12 AM, Geert Uytterhoeven wrote:
> Hi Mason,
>
> On Thu, Dec 6, 2018 at 8:31 AM <masonccyang@...c.com.tw> wrote:
>>>>> Re: [PATCH v2 1/2] spi: Add Renesas R-Car Gen3 RPC SPI controller driver
>>>>>
>>>>> On 12/03/2018 10:18 AM, Mason Yang wrote:
>>>>>> Add a driver for Renesas R-Car Gen3 RPC SPI controller.
>>>>>>
>>>>>> Signed-off-by: Mason Yang <masonccyang@...c.com.tw>
>
>>>>>> + xfercnt = xferpos;
>>>>>> + rpc->xferlen = xfer[--xferpos].len;
>>>>>> + rpc->cmd = RPC_SMCMR_CMD(((u8 *)xfer[0].tx_buf)[0]);
>>>>>
>>>>> Is the cast needed ?
>>>>
>>>> yes!
>>>
>>> Why ?
>>
>> Get a compiler warning due to tx_bug is void *, as Geert replied.
>>
>> Using get_unaligned(), patched code would be
>> ---------------------------------------------------------------
>> rpc->cmd = RPC_SMCMR_CMD(get_unaligned((u8 *)xfer[0].tx_buf));
>> ----------------------------------------------------------------
>
> Using get_unaligned(0 is a bit strange for accessing a single byte quantity.
> Please keep the normal pointer dereference (including the cast).
Oh, right, for single bytes this is OK.
--
Best regards,
Marek Vasut
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