[PATCH 06/32] spi: dw: Add support for the Kendryte K210 SoC

[Rob Herring]

On Mon, Nov 09, 2020 at 09:39:19PM +0000, Damien Le Moal wrote:
> On 2020/11/10 6:22, Serge Semin wrote:
> > On Sat, Nov 07, 2020 at 05:13:54PM +0900, Damien Le Moal wrote:
> >> The DW SPI master of the Kendryte K210 RISC-V SoC uses the 32-bits
> >> ctrlr0 register format. This SoC is also quite slow and gets significant
> >> SD card performance improvements from using no-delay polled transfers.
> >> Add the dw_spi_k210_init() function tied to the
> >> "canaan,kendryte-k210-spi" compatible string to set the
> >> DW_SPI_CAP_DFS_32 and DW_SPI_CAP_POLL_NODELAY DW SPI capability fields
> >> for this SoC.
> >>
> >> Signed-off-by: Damien Le Moal <damien.lemoal at wdc.com>
> >> ---
> >>  drivers/spi/spi-dw-mmio.c | 9 +++++++++
> >>  1 file changed, 9 insertions(+)
> >>
> >> diff --git a/drivers/spi/spi-dw-mmio.c b/drivers/spi/spi-dw-mmio.c
> >> index 3f1bc384cb45..a00def6c5b39 100644
> >> --- a/drivers/spi/spi-dw-mmio.c
> >> +++ b/drivers/spi/spi-dw-mmio.c
> >> @@ -223,6 +223,14 @@ static int dw_spi_keembay_init(struct platform_device *pdev,
> >>  	return 0;
> >>  }
> >>  
> >> +static int dw_spi_k210_init(struct platform_device *pdev,
> >> +			    struct dw_spi_mmio *dwsmmio)
> >> +{
> >> +	dwsmmio->dws.caps = DW_SPI_CAP_DFS_32 | DW_SPI_CAP_POLL_NODELAY;
> >> +
> >> +	return 0;
> >> +}
> >> +
> >>  static int dw_spi_mmio_probe(struct platform_device *pdev)
> >>  {
> >>  	int (*init_func)(struct platform_device *pdev,
> >> @@ -340,6 +348,7 @@ static const struct of_device_id dw_spi_mmio_of_match[] = {
> >>  	{ .compatible = "snps,dwc-ssi-1.01a", .data = dw_spi_dwc_ssi_init},
> >>  	{ .compatible = "intel,keembay-ssi", .data = dw_spi_keembay_init},
> >>  	{ .compatible = "microchip,sparx5-spi", dw_spi_mscc_sparx5_init},
> > 
> >> +	{ .compatible = "canaan,kendryte-k210-spi", .data = dw_spi_k210_init},
> > 
> > Other than the comments from Sean and Mark regarding the DFS_32
> > feature runtime detectability, I couldn't find a patch with adding the
> > new new compatible string into the DW APB SSI DT schema. Have I missed
> > it? If I haven't could you add one to the next version of the series?
> 
> Yes, I will. I forgot to change the DW DT binding doc for this. I did add a
> patch for the "polling" property but forgot the compatible string.
> 
> In any case, I think that this new compatible string change can be dropped by
> switching to automatically detecting the DFS32 and using a different solution
> than the polling property change I sent for the RX fifo overflow problem.

No, new SoC needs new compatible string. Especially if a new vendor. 

> 
> I am still going through all the emails trying to understand what to try next to
> avoid the polling "hack".

Use compatible.

Rob