Hi Brian,
On 11/12/2015 12:54 AM, Brian Norris wrote:
> In addition to my other comments:
>
[...]
>> + int (*spi_mtd_mmap_read)(struct spi_device *spi,
>> + loff_t from, size_t len,
>> + size_t *retlen, u_char *buf,
>> + u8 read_opcode, u8 addr_width,
>> + u8 dummy_bytes);
>
> This is seeming to be a longer and longer list of arguments. I know MTD
> has a bad habit of long argument lists (which then cause a ton of
> unnecessary churn when things need changed in the API), but perhaps we
> can limit the damage to the SPI layer. Perhaps this deserves a struct to
> encapsulate all the flash read arguments? Like:
>
> struct spi_flash_read_message {
> loff_t from;
> size_t len;
> size_t *retlen;
> void *buf;
> u8 read_opcode;
> u8 addr_width;
> u8 dummy_bits;
> // additional fields to describe rx_nbits for opcode/addr/data
> };
>
> struct spi_master {
> ...
> int (*spi_flash_read)(struct spi_device *spi,
> struct spi_flash_message *msg);
> };
Yeah.. I think struct encapsulation helps, this can also be used to pass
sg lists for dma in future. I will rework the series with your
suggestion to include nbits for opcode/addr/data.
Also, will add validation logic (similar to __spi_validate()) to check
whether master supports dual/quad mode for opcode/addr/data. I am
planning to add this validation code to spi_flash_read_validate(in place
of spi_mmap_read_supported())
Thanks!
--
Regards
Vignesh
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