[PATCH v8 01/28] spi: spi-mem: allow specifying whether an op is DTR or not

[Sean Anderson]

On 4/1/21 3:31 PM, Pratyush Yadav wrote:
> Each phase is given a separate 'dtr' field so mixed protocols like
> 4S-4D-4D can be supported.
> 
> Signed-off-by: Pratyush Yadav <p.yadav at ti.com>
> ---
>   drivers/spi/spi-mem.c | 3 +++
>   include/spi-mem.h     | 8 ++++++++
>   2 files changed, 11 insertions(+)
> 
> diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c
> index c095ae9505..427f7c13c5 100644
> --- a/drivers/spi/spi-mem.c
> +++ b/drivers/spi/spi-mem.c
> @@ -164,6 +164,9 @@ bool spi_mem_default_supports_op(struct spi_slave *slave,
>   				   op->data.dir == SPI_MEM_DATA_OUT))
>   		return false;
>   
> +	if (op->cmd.dtr || op->addr.dtr || op->dummy.dtr || op->data.dtr)
> +		return false;
> +
>   	return true;
>   }
>   EXPORT_SYMBOL_GPL(spi_mem_default_supports_op);
> diff --git a/include/spi-mem.h b/include/spi-mem.h
> index 8be3e2bf6b..9e6b044548 100644
> --- a/include/spi-mem.h
> +++ b/include/spi-mem.h
> @@ -71,6 +71,7 @@ enum spi_mem_data_dir {
>    * struct spi_mem_op - describes a SPI memory operation
>    * @cmd.buswidth: number of IO lines used to transmit the command
>    * @cmd.opcode: operation opcode
> + * @cmd.dtr: whether the command opcode should be sent in DTR mode or not
>    * @addr.nbytes: number of address bytes to send. Can be zero if the operation
>    *		 does not need to send an address
>    * @addr.buswidth: number of IO lines used to transmit the address cycles
> @@ -78,10 +79,13 @@ enum spi_mem_data_dir {
>    *	      Note that only @addr.nbytes are taken into account in this
>    *	      address value, so users should make sure the value fits in the
>    *	      assigned number of bytes.
> + * @addr.dtr: whether the address should be sent in DTR mode or not
>    * @dummy.nbytes: number of dummy bytes to send after an opcode or address. Can
>    *		  be zero if the operation does not require dummy bytes
>    * @dummy.buswidth: number of IO lanes used to transmit the dummy bytes
> + * @dummy.dtr: whether the dummy bytes should be sent in DTR mode or not
>    * @data.buswidth: number of IO lanes used to send/receive the data
> + * @data.dtr: whether the data should be sent in DTR mode or not
>    * @data.dir: direction of the transfer
>    * @data.buf.in: input buffer
>    * @data.buf.out: output buffer
> @@ -90,21 +94,25 @@ struct spi_mem_op {
>   	struct {
>   		u8 buswidth;
>   		u8 opcode;
> +		u8 dtr : 1;
>   	} cmd;
>   
>   	struct {
>   		u8 nbytes;
>   		u8 buswidth;
> +		u8 dtr : 1;
>   		u64 val;
>   	} addr;
>   
>   	struct {
>   		u8 nbytes;
>   		u8 buswidth;
> +		u8 dtr : 1;
>   	} dummy;
>   
>   	struct {
>   		u8 buswidth;
> +		u8 dtr : 1;
>   		enum spi_mem_data_dir dir;
>   		unsigned int nbytes;
>   		/* buf.{in,out} must be DMA-able. */
> 

I know this is following the Linux code, but are bitfields kosher for
U-Boot? This is more of a general question than a specific critique of
this code.

--Sean