Re: [PATCH] spi: cadence_qspi: Set tshsl_ns to at least one sclk_ns

[Michal Simek <michal.simek@amd.com>]

On 7/2/25 08:57, Venkatesh Yadav Abbarapu wrote:
> tshsl_ns is the clock delay for chip select deassert. This is the delay in
> master reference clocks for the length that the master mode chip select
> outputs are de-asserted between transactions.
> 
> The minimum delay is always SCLK period to ensure the chip select is never
> re-asserted within one SCLK period.
> 
> That is why tshsl_ns delay should be at least one sclk_ns value. If it is
> less than sclk_ns, set it equal to sclk_ns.
> 
> Signed-off-by: Ashok Reddy Soma <ashok.reddy.soma@amd.com>
> Signed-off-by: Venkatesh Yadav Abbarapu <venkatesh.abbarapu@amd.com>
> ---
>   drivers/spi/cadence_qspi_apb.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/spi/cadence_qspi_apb.c b/drivers/spi/cadence_qspi_apb.c
> index 65fb2d8f9fb..4696c09f754 100644
> --- a/drivers/spi/cadence_qspi_apb.c
> +++ b/drivers/spi/cadence_qspi_apb.c
> @@ -303,6 +303,10 @@ void cadence_qspi_apb_delay(void *reg_base,
>   		tshsl_ns -= sclk_ns + ref_clk_ns;
>   	if (tchsh_ns >= sclk_ns + 3 * ref_clk_ns)
>   		tchsh_ns -= sclk_ns + 3 * ref_clk_ns;
> +
> +	if (tshsl_ns < sclk_ns)
> +		tshsl_ns = sclk_ns;
> +
>   	tshsl = DIV_ROUND_UP(tshsl_ns, ref_clk_ns);
>   	tchsh = DIV_ROUND_UP(tchsh_ns, ref_clk_ns);
>   	tslch = DIV_ROUND_UP(tslch_ns, ref_clk_ns);

Applied.
M