spi: spi-fsl-lpspi: support multiple cs for lpspi

support to get chip select number from DT file.

Signed-off-by: Han Xu <han.xu@nxp.com>
Link: https://lore.kernel.org/r/20221206225410.604482-1-han.xu@nxp.com
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-fsl-lpspi.c

@@ -98,6 +98,7 @@ struct fsl_lpspi_data {
 	struct clk *clk_ipg;
 	struct clk *clk_per;
 	bool is_slave;
+	u32 num_cs;
 	bool is_only_cs1;
 	bool is_first_byte;
 
@@ -840,6 +841,9 @@ static int fsl_lpspi_probe(struct platform_device *pdev)
 	fsl_lpspi->is_slave = is_slave;
 	fsl_lpspi->is_only_cs1 = of_property_read_bool((&pdev->dev)->of_node,
 						"fsl,spi-only-use-cs1-sel");
+	if (of_property_read_u32((&pdev->dev)->of_node, "num-cs",
+				 &fsl_lpspi->num_cs))
+		fsl_lpspi->num_cs = 1;
 
 	controller->bits_per_word_mask = SPI_BPW_RANGE_MASK(8, 32);
 	controller->transfer_one = fsl_lpspi_transfer_one;
@@ -849,6 +853,7 @@ static int fsl_lpspi_probe(struct platform_device *pdev)
 	controller->flags = SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX;
 	controller->dev.of_node = pdev->dev.of_node;
 	controller->bus_num = pdev->id;
+	controller->num_chipselect = fsl_lpspi->num_cs;
 	controller->slave_abort = fsl_lpspi_slave_abort;
 	if (!fsl_lpspi->is_slave)
 		controller->use_gpio_descriptors = true;