From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boris Brezillon Subject: Re: [PATCH v2 2/4] spi: spi-fsl-dspi: Fix delete the processing of undefined bitmask for rxdata Date: Sun, 30 Sep 2018 12:17:07 +0200 Message-ID: <20180930121707.4724edd6@bbrezillon> References: <20180930092535.24544-1-chuanhua.han@nxp.com> <20180930092535.24544-2-chuanhua.han@nxp.com> <20180930120659.71b0e1e5@bbrezillon> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Cc: "broonie@kernel.org" , "linux-spi@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "eha@deif.com" To: Chuanhua Han Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-spi.vger.kernel.org On Sun, 30 Sep 2018 10:10:14 +0000 Chuanhua Han wrote: > > -----Original Message----- > > From: Boris Brezillon > > Sent: 2018年9月30日 18:07 > > To: Chuanhua Han > > Cc: broonie@kernel.org; linux-spi@vger.kernel.org; > > linux-kernel@vger.kernel.org; eha@deif.com > > Subject: Re: [PATCH v2 2/4] spi: spi-fsl-dspi: Fix delete the processing of > > undefined bitmask for rxdata > > > > On Sun, 30 Sep 2018 17:25:33 +0800 > > Chuanhua Han wrote: > > > > > This patch fixes the problem of rxdata being equal to 0 during the > > > XSPI mode transfer of the dspi controller. > > > In XSPI mode, If it is not deleted, the value of rxdata will be equal > > > to 0, and the data received will not be received correctly, causing > > > the receiving transfer of the spi to fail. > > > > > > Signed-off-by: Chuanhua Han > > > --- > > > Changes in v2: > > > -The original patch is divided into multiple patches(the original > > > patch theme is "spi: spi-fsl-dspi: Fix support for XSPI transport > > > mode"),one of which is segmented. > > > > > > drivers/spi/spi-fsl-dspi.c | 3 --- > > > 1 file changed, 3 deletions(-) > > > > > > diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c > > > index 3082e72e4f6c..4dc1064bf408 100644 > > > --- a/drivers/spi/spi-fsl-dspi.c > > > +++ b/drivers/spi/spi-fsl-dspi.c > > > @@ -243,9 +243,6 @@ static void dspi_push_rx(struct fsl_dspi *dspi, u32 > > rxdata) > > > if (!dspi->rx) > > > return; > > > > > > - /* Mask of undefined bits */ > > > - rxdata &= (1 << dspi->bits_per_word) - 1; > > > - > > > > Why not > In xspi mode, the value of rxdata after the statement is processed is equal to 0 no matter what data is received. Only if dspi->bits_per_word is 0. Actually, I just had a look, and xfer->bits_per_word should never be 0 because spi_validate() makes sure it's initialized [1]. Don't know where dpsi->bits_per_word comes from, but maybe you have a problem there (dpsi->bits_per_word and xfer->bits_per_word not in sync). [1]https://elixir.bootlin.com/linux/v4.19-rc5/source/drivers/spi/spi.c#L2869