RE: [PATCH 1/2] spi: spi-mem: Add the spi_set_xfer_bpw function

[Chuanhua Han]

> -----Original Message-----
> From: Chuanhua Han <chuanhua.han@xxxxxxx>
> Sent: 2018年9月21日 15:06
> To: broonie@xxxxxxxxxx
> Cc: linux-spi@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; eha@xxxxxxxx;
> boris.brezillon@xxxxxxxxxxx; Chuanhua Han <chuanhua.han@xxxxxxx>
> Subject: [PATCH 1/2] spi: spi-mem: Add the spi_set_xfer_bpw function
> 
> Before we add this spi_transfer to the spi_message chain table, we need
> bits_per_word_mask based on spi_control to set the bits_per_word of this
> spi_transfer.
> 
> Signed-off-by: Chuanhua Han <chuanhua.han@xxxxxxx>
> ---
>  drivers/spi/spi-mem.c | 39 +++++++++++++++++++++++++++++++++++++++
>  1 file changed, 39 insertions(+)
> 
> diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c index
> eb72dba71d83..717e711c0952 100644
> --- a/drivers/spi/spi-mem.c
> +++ b/drivers/spi/spi-mem.c
> @@ -175,6 +175,41 @@ bool spi_mem_supports_op(struct spi_mem *mem,
> const struct spi_mem_op *op)  }
> EXPORT_SYMBOL_GPL(spi_mem_supports_op);
> 
> +/**
> + * spi_set_xfer_bpw() - Set the bits_per_word for each transfer based on
> + *			the bits_per_word_mask of the spi controller
> + * @ctrl: the spi controller
> + * @xfer: the spi transfer
> + *
> + * This function sets the bits_per_word for each transfer based on the
> +spi
> + * controller's bits_per_word_mask to improve the efficiency of spi transport.
> + *
> + * Return: 0 in case of success, a negative error code otherwise.
> + */
> +int spi_set_xfer_bpw(struct spi_controller *ctlr, struct spi_transfer
> +*xfer) {
> +	if (!ctlr || !xfer) {
> +		dev_err(&ctlr->dev,
> +			"Fail to set bits_per_word for spi transfer\n");
> +		return -EINVAL;
> +	}
> +
> +	if (ctlr->bits_per_word_mask) {
> +		if (!(xfer->len % 4)) {
> +			if (ctlr->bits_per_word_mask & SPI_BPW_MASK(32))
> +				xfer->bits_per_word = 32;
> +		} else if (!(xfer->len % 2)) {
> +			if (ctlr->bits_per_word_mask & SPI_BPW_MASK(16))
> +				xfer->bits_per_word = 16;
> +		} else {
> +			xfer->bits_per_word = 8;
> +		}
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(spi_set_xfer_bpw);
> +
>  /**
>   * spi_mem_exec_op() - Execute a memory operation
>   * @mem: the SPI memory
> @@ -252,6 +287,7 @@ int spi_mem_exec_op(struct spi_mem *mem, const
> struct spi_mem_op *op)
>  	xfers[xferpos].tx_buf = tmpbuf;
>  	xfers[xferpos].len = sizeof(op->cmd.opcode);
>  	xfers[xferpos].tx_nbits = op->cmd.buswidth;
> +	spi_set_xfer_bpw(ctlr, &xfers[xferpos]);
>  	spi_message_add_tail(&xfers[xferpos], &msg);
>  	xferpos++;
>  	totalxferlen++;
> @@ -266,6 +302,7 @@ int spi_mem_exec_op(struct spi_mem *mem, const
> struct spi_mem_op *op)
>  		xfers[xferpos].tx_buf = tmpbuf + 1;
>  		xfers[xferpos].len = op->addr.nbytes;
>  		xfers[xferpos].tx_nbits = op->addr.buswidth;
> +		spi_set_xfer_bpw(ctlr, &xfers[xferpos]);
>  		spi_message_add_tail(&xfers[xferpos], &msg);
>  		xferpos++;
>  		totalxferlen += op->addr.nbytes;
> @@ -276,6 +313,7 @@ int spi_mem_exec_op(struct spi_mem *mem, const
> struct spi_mem_op *op)
>  		xfers[xferpos].tx_buf = tmpbuf + op->addr.nbytes + 1;
>  		xfers[xferpos].len = op->dummy.nbytes;
>  		xfers[xferpos].tx_nbits = op->dummy.buswidth;
> +		spi_set_xfer_bpw(ctlr, &xfers[xferpos]);
>  		spi_message_add_tail(&xfers[xferpos], &msg);
>  		xferpos++;
>  		totalxferlen += op->dummy.nbytes;
> @@ -291,6 +329,7 @@ int spi_mem_exec_op(struct spi_mem *mem, const
> struct spi_mem_op *op)
>  		}
> 
>  		xfers[xferpos].len = op->data.nbytes;
> +		spi_set_xfer_bpw(ctlr, &xfers[xferpos]);
>  		spi_message_add_tail(&xfers[xferpos], &msg);
>  		xferpos++;
>  		totalxferlen += op->data.nbytes;
> --
> 2.17.1
Hi,all
Could you please help me to see the fix of this patch? What changes need to be made? 
Looking forward to your valuable comments and criticism, thank you very much!!!
Thanks,
Chuanhua