[PATCH v1 3/3] drivers: xilinx_spi: Probe fifo_depth at runtime

[Michal Simek]

On 11/11/23 18:31, Mayuresh Chitale wrote:
> If the fifo-size DT parameter is not provided then probe the
> controller's fifo depth at runtime. This is ported from a patch
> in the Linux Xilinx SPI driver.
> 
> Signed-off-by: Mayuresh Chitale <mchitale at ventanamicro.com>
> Link: https://lore.kernel.org/r/1422029330-10971-5-git-send-email-ricardo.ribalda@gmail.com
> ---
>   drivers/spi/xilinx_spi.c | 23 +++++++++++++++++++++++
>   1 file changed, 23 insertions(+)
> 
> diff --git a/drivers/spi/xilinx_spi.c b/drivers/spi/xilinx_spi.c
> index b63cda2091..99ae5be291 100644
> --- a/drivers/spi/xilinx_spi.c
> +++ b/drivers/spi/xilinx_spi.c
> @@ -109,6 +109,27 @@ struct xilinx_spi_priv {
>   	u8 startup;
>   };
>   
> +static int xilinx_spi_find_buffer_size(struct xilinx_spi_regs *regs)
> +{
> +	u8 sr;
> +	int n_words = 0;
> +
> +	/*
> +	 * Before the buffer_size detection we reset the core
> +	 * to make sure we start with a clean state.


nit: can you please remove "we" above? It should be written in imperative mood.


> +	 */
> +	writel(SPISSR_RESET_VALUE, &regs->srr);
> +
> +	/* Fill the Tx FIFO with as many words as possible */
> +	do {
> +		writel(0, &regs->spidtr);
> +		sr = readl(&regs->spisr);
> +		n_words++;
> +	} while (!(sr & SPISR_TX_FULL));
> +
> +	return n_words;
> +}
> +
>   static int xilinx_spi_probe(struct udevice *bus)
>   {
>   	struct xilinx_spi_priv *priv = dev_get_priv(bus);
> @@ -116,6 +137,8 @@ static int xilinx_spi_probe(struct udevice *bus)
>   
>   	regs = priv->regs = dev_read_addr_ptr(bus);
>   	priv->fifo_depth = dev_read_u32_default(bus, "fifo-size", 0);
> +	if (!priv->fifo_depth)
> +		priv->fifo_depth = xilinx_spi_find_buffer_size(regs);
>   
>   	writel(SPISSR_RESET_VALUE, &regs->srr);
>   

When above fixed feel free to add
Reviewed-by: Michal Simek <michal.simek at amd.com>

Thanks,
Michal