Re: [PATCH V1 18/26] spi: tegra114: add support for hw based cs

[Mark Brown]

On Tue, Mar 26, 2019 at 10:56:39PM -0700, Sowjanya Komatineni wrote:

> Tegra SPI driver default uses SW CS control for transfers and HW CS
> control can be enabled through SPI client device node DT property
> nvidia,enable-hw-based-cs and is used only for single transfers.

Why have a property - if this feature works and is useful why would a
system ever not want to use it?

> +	single_xfer = list_is_singular(&msg->transfers);
>  	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
>  		u32 cmd1;
>  
>  		reinit_completion(&tspi->xfer_completion);
>  
> -		cmd1 = tegra_spi_setup_transfer_one(spi, xfer, is_first_msg);
> +		cmd1 = tegra_spi_setup_transfer_one(spi, xfer, is_first_msg,
> +						    single_xfer);

It's not sufficient to check if there's only one transfer, you also need
to make sure that the driver isn't using cs_change to use non-standard
chip select handling.

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