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

[mchitale at ventanamicro.com]

On Mon, 2023-11-13 at 10:06 +0100, Michal Simek wrote:
> 
> 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.
Ok.
> 
> 
> > +	 */
> > +	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>
Ok.
> 
> Thanks,
> Michal