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Date: Tue, 13 Feb 2024 18:06:57 +0100
From: Ralf Schlatterbeck <rsc@runtux.com>
To: Mark Brown <broonie@kernel.org>, Shawn Guo <shawnguo@kernel.org>,
	Sascha Hauer <s.hauer@pengutronix.de>,
	Pengutronix Kernel Team <kernel@pengutronix.de>,
	Fabio Estevam <festevam@gmail.com>,
	NXP Linux Team <linux-imx@nxp.com>, linux-spi@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/1] spi-mxs: Fix chipselect glitch
Message-ID: <20240213170657.puwlx5pjl3odcs2k@runtux.com>
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On Fri, Feb 02, 2024 at 12:53:30PM +0100, Ralf Schlatterbeck wrote:
> There was a change in the mxs-dma engine that uses a new custom flag.
> The change was not applied to the mxs spi driver.
> This results in chipselect being deasserted too early.
> This fixes the chipselect problem by using the new flag in the mxs-spi
> driver.
> 
> Fixes: ceeeb99cd821 ("dmaengine: mxs: rename custom flag")
> Signed-off-by: Ralf Schlatterbeck <rsc@runtux.com>
> ---
> For oscilloscope screenshots and a verbose explanation see my blog post
> at https://blog.runtux.com/posts/2024/02/01/
> History:
> Omit the line break change from patch requested by Marc Kleine-Budde
> <mkl@pengutronix.de>
> 
>  drivers/spi/spi-mxs.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/spi/spi-mxs.c b/drivers/spi/spi-mxs.c
> index 1bf080339b5a..88cbe4f00cc3 100644
> --- a/drivers/spi/spi-mxs.c
> +++ b/drivers/spi/spi-mxs.c
> @@ -39,6 +39,7 @@
>  #include <linux/spi/spi.h>
>  #include <linux/spi/mxs-spi.h>
>  #include <trace/events/spi.h>
> +#include <linux/dma/mxs-dma.h>
>  
>  #define DRIVER_NAME		"mxs-spi"
>  
> @@ -252,7 +253,7 @@ static int mxs_spi_txrx_dma(struct mxs_spi *spi,
>  		desc = dmaengine_prep_slave_sg(ssp->dmach,
>  				&dma_xfer[sg_count].sg, 1,
>  				(flags & TXRX_WRITE) ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM,
> -				DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
> +				DMA_PREP_INTERRUPT | MXS_DMA_CTRL_WAIT4END);
>  
>  		if (!desc) {
>  			dev_err(ssp->dev,
> -- 
> 2.20.1
> 
> -- 
> Dr. Ralf Schlatterbeck                  Tel:   +43/2243/26465-16
> Open Source Consulting                  www:   www.runtux.com
> Reichergasse 131, A-3411 Weidling       email: office@runtux.com

Any news on this, will it be picked up for the next merge window?

Thanks + kind regards
Ralf Schlatterbeck
-- 
Dr. Ralf Schlatterbeck                  Tel:   +43/2243/26465-16
Open Source Consulting                  www:   www.runtux.com
Reichergasse 131, A-3411 Weidling       email: office@runtux.com