spi: rockchip: Support SPI_CS_HIGH

1.Add standard spi-cs-high support
2.Refer to spi-controller.yaml for details

Signed-off-by: Jon Lin <jon.lin@rock-chips.com>
Link: https://lore.kernel.org/r/20210621104848.19539-2-jon.lin@rock-chips.com
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-rockchip.c

@@ -107,6 +107,8 @@
 #define CR0_OPM_MASTER				0x0
 #define CR0_OPM_SLAVE				0x1
 
+#define CR0_SOI_OFFSET				23
+
 #define CR0_MTM_OFFSET				0x21
 
 /* Bit fields in SER, 2bit */
@@ -236,7 +238,7 @@ static void rockchip_spi_set_cs(struct spi_device *spi, bool enable)
 {
 	struct spi_controller *ctlr = spi->controller;
 	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);
-	bool cs_asserted = !enable;
+	bool cs_asserted = spi->mode & SPI_CS_HIGH ? enable : !enable;
 
 	/* Return immediately for no-op */
 	if (cs_asserted == rs->cs_asserted[spi->chip_select])
@@ -507,6 +509,8 @@ static int rockchip_spi_config(struct rockchip_spi *rs,
 	cr0 |= (spi->mode & 0x3U) << CR0_SCPH_OFFSET;
 	if (spi->mode & SPI_LSB_FIRST)
 		cr0 |= CR0_FBM_LSB << CR0_FBM_OFFSET;
+	if (spi->mode & SPI_CS_HIGH)
+		cr0 |= BIT(spi->chip_select) << CR0_SOI_OFFSET;
 
 	if (xfer->rx_buf && xfer->tx_buf)
 		cr0 |= CR0_XFM_TR << CR0_XFM_OFFSET;
@@ -795,6 +799,14 @@ static int rockchip_spi_probe(struct platform_device *pdev)
 		ctlr->can_dma = rockchip_spi_can_dma;
 	}
 
+	switch (readl_relaxed(rs->regs + ROCKCHIP_SPI_VERSION)) {
+	case ROCKCHIP_SPI_VER2_TYPE2:
+		ctlr->mode_bits |= SPI_CS_HIGH;
+		break;
+	default:
+		break;
+	}
+
 	ret = devm_spi_register_controller(&pdev->dev, ctlr);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "Failed to register controller\n");