spi: nxp-fspi: Support per spi-mem operation frequency switches

Every ->exec_op() call correctly configures the spi bus speed to the
maximum allowed frequency for the memory using the constant spi default
parameter. Since we can now have per-operation constraints, let's use
the value that comes from the spi-mem operation structure instead. In
case there is no specific limitation for this operation, the default spi
device value will be given anyway.

The per-operation frequency capability is thus advertised to the spi-mem
core.

Cc: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://patch.msgid.link/20241224-winbond-6-11-rc1-quad-support-v2-12-ad218dbc406f@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: miquelraynal

drivers/spi/spi-nxp-fspi.c

@@ -705,9 +705,10 @@ static void nxp_fspi_dll_calibration(struct nxp_fspi *f)
  * Value for rest of the CS FLSHxxCR0 register would be zero.
  *
  */
-static void nxp_fspi_select_mem(struct nxp_fspi *f, struct spi_device *spi)
+static void nxp_fspi_select_mem(struct nxp_fspi *f, struct spi_device *spi,
+				const struct spi_mem_op *op)
 {
-	unsigned long rate = spi->max_speed_hz;
+	unsigned long rate = op->max_freq;
 	int ret;
 	uint64_t size_kb;
 
@@ -931,7 +932,7 @@ static int nxp_fspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
 				   FSPI_STS0_ARB_IDLE, 1, POLL_TOUT, true);
 	WARN_ON(err);
 
-	nxp_fspi_select_mem(f, mem->spi);
+	nxp_fspi_select_mem(f, mem->spi, op);
 
 	nxp_fspi_prepare_lut(f, op);
 	/*
@@ -1149,6 +1150,10 @@ static const struct spi_controller_mem_ops nxp_fspi_mem_ops = {
 	.get_name = nxp_fspi_get_name,
 };
 
+static const struct spi_controller_mem_caps nxp_fspi_mem_caps = {
+	.per_op_freq = true,
+};
+
 static int nxp_fspi_probe(struct platform_device *pdev)
 {
 	struct spi_controller *ctlr;
@@ -1246,6 +1251,7 @@ static int nxp_fspi_probe(struct platform_device *pdev)
 	ctlr->bus_num = -1;
 	ctlr->num_chipselect = NXP_FSPI_MAX_CHIPSELECT;
 	ctlr->mem_ops = &nxp_fspi_mem_ops;
+	ctlr->mem_caps = &nxp_fspi_mem_caps;
 
 	nxp_fspi_default_setup(f);