linux-kernel - Re: [PATCH 2/5] spi: spi-nxp-fspi: Add the DDR LUT command support

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Message-ID: <aMmC167rzSYrIeTd@lizhi-Precision-Tower-5810>
Date: Tue, 16 Sep 2025 11:31:35 -0400
From: Frank Li <Frank.li@....com>
To: Haibo Chen <haibo.chen@....com>
Cc: Han Xu <han.xu@....com>, Yogesh Gaur <yogeshgaur.83@...il.com>,
	Mark Brown <broonie@...nel.org>, linux-spi@...r.kernel.org,
	imx@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/5] spi: spi-nxp-fspi: Add the DDR LUT command support

On Tue, Sep 16, 2025 at 03:56:41PM +0800, Haibo Chen wrote:
> For DTR mode, flexspi need to use DDR LUT command, flexspi will switch
> to DDR mode when detect the DDR LUT command.
>
> Signed-off-by: Haibo Chen <haibo.chen@....com>
> ---
>  drivers/spi/spi-nxp-fspi.c | 22 +++++++++++++++++-----
>  1 file changed, 17 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/spi/spi-nxp-fspi.c b/drivers/spi/spi-nxp-fspi.c
> index a1c9ad03379682dc1fc2908fbd83e1ae8e91588f..6b3e6b427ba84734a2359a964635a8f05cd146fd 100644
> --- a/drivers/spi/spi-nxp-fspi.c
> +++ b/drivers/spi/spi-nxp-fspi.c
> @@ -559,12 +559,22 @@ static void nxp_fspi_prepare_lut(struct nxp_fspi *f,
>  	u32 target_lut_reg;
>
>  	/* cmd */
> -	lutval[0] |= LUT_DEF(0, LUT_CMD, LUT_PAD(op->cmd.buswidth),
> -			     op->cmd.opcode);
> +	if (op->cmd.dtr) {
> +		lutval[0] |= LUT_DEF(0, LUT_CMD_DDR, LUT_PAD(op->cmd.buswidth),
> +				     op->cmd.opcode >> 8);
> +		lutval[lutidx / 2] |= LUT_DEF(lutidx, LUT_CMD_DDR,
> +					      LUT_PAD(op->cmd.buswidth),
> +					      op->cmd.opcode & 0xFF);
> +		lutidx++;
> +	} else {
> +		lutval[0] |= LUT_DEF(0, LUT_CMD, LUT_PAD(op->cmd.buswidth),
> +				     op->cmd.opcode);
> +	}
>
>  	/* addr bytes */
>  	if (op->addr.nbytes) {
> -		lutval[lutidx / 2] |= LUT_DEF(lutidx, LUT_ADDR,
> +		lutval[lutidx / 2] |= LUT_DEF(lutidx, op->addr.dtr ?
> +					      LUT_ADDR_DDR : LUT_ADDR,

					      op->addr.dtr ?  UT_ADDR_DDR : LUT_ADDR,

put ? to one line to look better.

>  					      LUT_PAD(op->addr.buswidth),
>  					      op->addr.nbytes * 8);
>  		lutidx++;
> @@ -572,7 +582,8 @@ static void nxp_fspi_prepare_lut(struct nxp_fspi *f,
>
>  	/* dummy bytes, if needed */
>  	if (op->dummy.nbytes) {
> -		lutval[lutidx / 2] |= LUT_DEF(lutidx, LUT_DUMMY,
> +		lutval[lutidx / 2] |= LUT_DEF(lutidx, op->dummy.dtr ?
> +					      LUT_DUMMY_DDR : LUT_DUMMY,

the same here.

Reviewed-by: Frank Li <Frank.Li@....com>

>  		/*
>  		 * Due to FlexSPI controller limitation number of PAD for dummy
>  		 * buswidth needs to be programmed as equal to data buswidth.
> @@ -587,7 +598,8 @@ static void nxp_fspi_prepare_lut(struct nxp_fspi *f,
>  	if (op->data.nbytes) {
>  		lutval[lutidx / 2] |= LUT_DEF(lutidx,
>  					      op->data.dir == SPI_MEM_DATA_IN ?
> -					      LUT_NXP_READ : LUT_NXP_WRITE,
> +					      (op->data.dtr ? LUT_READ_DDR : LUT_NXP_READ) :
> +					      (op->data.dtr ? LUT_WRITE_DDR : LUT_NXP_WRITE),
>  					      LUT_PAD(op->data.buswidth),
>  					      0);
>  		lutidx++;
>
> --
> 2.34.1
>