[PATCH 19/21] spi: s3c64xx: add support for google,gs101-spi

[Tudor Ambarus]

Add support for GS101 SPI. All the SPI nodes on GS101 have 64 bytes
FIFOs, infer the FIFO size from the compatible. GS101 allows just 32bit
register accesses, otherwise a Serror Interrupt is raised. Do the write
reg accesses in 32 bits.

Signed-off-by: Tudor Ambarus <tudor.ambarus@xxxxxxxxxx>
---
 drivers/spi/spi-s3c64xx.c | 50 +++++++++++++++++++++++++++++++++------
 1 file changed, 43 insertions(+), 7 deletions(-)

diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
index 62671b2d594a..c4ddd2859ba4 100644
--- a/drivers/spi/spi-s3c64xx.c
+++ b/drivers/spi/spi-s3c64xx.c
@@ -20,6 +20,7 @@
 
 #define MAX_SPI_PORTS				12
 #define S3C64XX_SPI_QUIRK_CS_AUTO		BIT(1)
+#define S3C64XX_SPI_GS1O1_32BIT_REG_IO_WIDTH	BIT(2)
 #define AUTOSUSPEND_TIMEOUT			2000
 
 /* Registers and bit-fields */
@@ -131,6 +132,7 @@ struct s3c64xx_spi_dma_data {
  * @rx_lvl_offset: Bit offset of RX_FIFO_LVL bits in SPI_STATUS regiter.
  * @tx_st_done: Bit offset of TX_DONE bit in SPI_STATUS regiter.
  * @clk_div: Internal clock divider
+ * @fifosize: size of the FIFO
  * @quirks: Bitmask of known quirks
  * @high_speed: True, if the controller supports HIGH_SPEED_EN bit.
  * @clk_from_cmu: True, if the controller does not include a clock mux and
@@ -149,6 +151,7 @@ struct s3c64xx_spi_port_config {
 	int	tx_st_done;
 	int	quirks;
 	int	clk_div;
+	unsigned int fifosize;
 	bool	high_speed;
 	bool	clk_from_cmu;
 	bool	clk_ioclk;
@@ -175,6 +178,7 @@ struct s3c64xx_spi_port_config {
  * @tx_dma: Local transmit DMA data (e.g. chan and direction)
  * @port_conf: Local SPI port configuartion data
  * @port_id: Port identification number
+ * @fifosize: size of the FIFO for this port
  */
 struct s3c64xx_spi_driver_data {
 	void __iomem                    *regs;
@@ -194,6 +198,7 @@ struct s3c64xx_spi_driver_data {
 	struct s3c64xx_spi_dma_data	tx_dma;
 	const struct s3c64xx_spi_port_config	*port_conf;
 	unsigned int			port_id;
+	unsigned int			fifosize;
 };
 
 static void s3c64xx_flush_fifo(struct s3c64xx_spi_driver_data *sdd)
@@ -403,7 +408,7 @@ static bool s3c64xx_spi_can_dma(struct spi_controller *host,
 	struct s3c64xx_spi_driver_data *sdd = spi_controller_get_devdata(host);
 
 	if (sdd->rx_dma.ch && sdd->tx_dma.ch)
-		return xfer->len > FIFO_DEPTH(sdd);
+		return xfer->len > sdd->fifosize;
 
 	return false;
 }
@@ -447,12 +452,22 @@ static int s3c64xx_enable_datapath(struct s3c64xx_spi_driver_data *sdd,
 					xfer->tx_buf, xfer->len / 4);
 				break;
 			case 16:
-				iowrite16_rep(regs + S3C64XX_SPI_TX_DATA,
-					xfer->tx_buf, xfer->len / 2);
+				if (sdd->port_conf->quirks &
+				    S3C64XX_SPI_GS1O1_32BIT_REG_IO_WIDTH)
+					iowrite16_32_rep(regs + S3C64XX_SPI_TX_DATA,
+							 xfer->tx_buf, xfer->len / 2);
+				else
+					iowrite16_rep(regs + S3C64XX_SPI_TX_DATA,
+						      xfer->tx_buf, xfer->len / 2);
 				break;
 			default:
-				iowrite8_rep(regs + S3C64XX_SPI_TX_DATA,
-					xfer->tx_buf, xfer->len);
+				if (sdd->port_conf->quirks &
+				    S3C64XX_SPI_GS1O1_32BIT_REG_IO_WIDTH)
+					iowrite8_32_rep(regs + S3C64XX_SPI_TX_DATA,
+							xfer->tx_buf, xfer->len);
+				else
+					iowrite8_rep(regs + S3C64XX_SPI_TX_DATA,
+						     xfer->tx_buf, xfer->len);
 				break;
 			}
 		}
@@ -696,7 +711,7 @@ static int s3c64xx_spi_transfer_one(struct spi_controller *host,
 				    struct spi_transfer *xfer)
 {
 	struct s3c64xx_spi_driver_data *sdd = spi_controller_get_devdata(host);
-	const unsigned int fifo_len = FIFO_DEPTH(sdd);
+	const unsigned int fifo_len = sdd->fifosize;
 	const void *tx_buf = NULL;
 	void *rx_buf = NULL;
 	int target_len = 0, origin_len = 0;
@@ -1145,6 +1160,11 @@ static int s3c64xx_spi_probe(struct platform_device *pdev)
 		sdd->port_id = pdev->id;
 	}
 
+	if (sdd->port_conf->fifosize)
+		sdd->fifosize = sdd->port_conf->fifosize;
+	else
+		sdd->fifosize = FIFO_DEPTH(sdd);
+
 	sdd->cur_bpw = 8;
 
 	sdd->tx_dma.direction = DMA_MEM_TO_DEV;
@@ -1234,7 +1254,7 @@ static int s3c64xx_spi_probe(struct platform_device *pdev)
 	dev_dbg(&pdev->dev, "Samsung SoC SPI Driver loaded for Bus SPI-%d with %d Targets attached\n",
 					sdd->port_id, host->num_chipselect);
 	dev_dbg(&pdev->dev, "\tIOmem=[%pR]\tFIFO %dbytes\n",
-					mem_res, FIFO_DEPTH(sdd));
+					mem_res, sdd->fifosize);
 
 	pm_runtime_mark_last_busy(&pdev->dev);
 	pm_runtime_put_autosuspend(&pdev->dev);
@@ -1362,6 +1382,18 @@ static const struct dev_pm_ops s3c64xx_spi_pm = {
 			   s3c64xx_spi_runtime_resume, NULL)
 };
 
+static const struct s3c64xx_spi_port_config gs101_spi_port_config = {
+	.fifosize	= 64,
+	.rx_lvl_offset  = 15,
+	.tx_st_done     = 25,
+	.clk_div        = 4,
+	.high_speed	= true,
+	.clk_from_cmu	= true,
+	.has_loopback	= true,
+	.quirks		= S3C64XX_SPI_QUIRK_CS_AUTO |
+			  S3C64XX_SPI_GS1O1_32BIT_REG_IO_WIDTH,
+};
+
 static const struct s3c64xx_spi_port_config s3c2443_spi_port_config = {
 	.fifo_lvl_mask	= { 0x7f },
 	.rx_lvl_offset	= 13,
@@ -1452,6 +1484,10 @@ static const struct platform_device_id s3c64xx_spi_driver_ids[] = {
 };
 
 static const struct of_device_id s3c64xx_spi_dt_match[] = {
+	{
+		.compatible = "google,gs101-spi",
+		.data = &gs101_spi_port_config,
+	},
 	{
 		.compatible = "samsung,s3c2443-spi",
 		.data = &s3c2443_spi_port_config,
-- 
2.43.0.429.g432eaa2c6b-goog