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path: root/drivers/spi/spi-cadence.c
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Diffstat (limited to 'drivers/spi/spi-cadence.c')
-rw-r--r--drivers/spi/spi-cadence.c37
1 files changed, 31 insertions, 6 deletions
diff --git a/drivers/spi/spi-cadence.c b/drivers/spi/spi-cadence.c
index a23d4f6329f5..6a7f7df1e776 100644
--- a/drivers/spi/spi-cadence.c
+++ b/drivers/spi/spi-cadence.c
@@ -69,6 +69,7 @@
#define CDNS_SPI_BAUD_DIV_SHIFT 3 /* Baud rate divisor shift in CR */
#define CDNS_SPI_SS_SHIFT 10 /* Slave Select field shift in CR */
#define CDNS_SPI_SS0 0x1 /* Slave Select zero */
+#define CDNS_SPI_NOSS 0xF /* No Slave select */
/*
* SPI Interrupt Registers bit Masks
@@ -92,9 +93,6 @@
#define CDNS_SPI_ER_ENABLE 0x00000001 /* SPI Enable Bit Mask */
#define CDNS_SPI_ER_DISABLE 0x0 /* SPI Disable Bit Mask */
-/* SPI FIFO depth in bytes */
-#define CDNS_SPI_FIFO_DEPTH 128
-
/* Default number of chip select lines */
#define CDNS_SPI_DEFAULT_NUM_CS 4
@@ -110,6 +108,7 @@
* @rx_bytes: Number of bytes requested
* @dev_busy: Device busy flag
* @is_decoded_cs: Flag for decoder property set or not
+ * @tx_fifo_depth: Depth of the TX FIFO
*/
struct cdns_spi {
void __iomem *regs;
@@ -123,6 +122,7 @@ struct cdns_spi {
int rx_bytes;
u8 dev_busy;
u32 is_decoded_cs;
+ unsigned int tx_fifo_depth;
};
/* Macros for the SPI controller read/write */
@@ -304,7 +304,7 @@ static void cdns_spi_fill_tx_fifo(struct cdns_spi *xspi)
{
unsigned long trans_cnt = 0;
- while ((trans_cnt < CDNS_SPI_FIFO_DEPTH) &&
+ while ((trans_cnt < xspi->tx_fifo_depth) &&
(xspi->tx_bytes > 0)) {
/* When xspi in busy condition, bytes may send failed,
@@ -450,20 +450,43 @@ static int cdns_prepare_transfer_hardware(struct spi_master *master)
* @master: Pointer to the spi_master structure which provides
* information about the controller.
*
- * This function disables the SPI master controller.
+ * This function disables the SPI master controller when no slave selected.
*
* Return: 0 always
*/
static int cdns_unprepare_transfer_hardware(struct spi_master *master)
{
struct cdns_spi *xspi = spi_master_get_devdata(master);
+ u32 ctrl_reg;
- cdns_spi_write(xspi, CDNS_SPI_ER, CDNS_SPI_ER_DISABLE);
+ /* Disable the SPI if slave is deselected */
+ ctrl_reg = cdns_spi_read(xspi, CDNS_SPI_CR);
+ ctrl_reg = (ctrl_reg & CDNS_SPI_CR_SSCTRL) >> CDNS_SPI_SS_SHIFT;
+ if (ctrl_reg == CDNS_SPI_NOSS)
+ cdns_spi_write(xspi, CDNS_SPI_ER, CDNS_SPI_ER_DISABLE);
return 0;
}
/**
+ * cdns_spi_detect_fifo_depth - Detect the FIFO depth of the hardware
+ * @xspi: Pointer to the cdns_spi structure
+ *
+ * The depth of the TX FIFO is a synthesis configuration parameter of the SPI
+ * IP. The FIFO threshold register is sized so that its maximum value can be the
+ * FIFO size - 1. This is used to detect the size of the FIFO.
+ */
+static void cdns_spi_detect_fifo_depth(struct cdns_spi *xspi)
+{
+ /* The MSBs will get truncated giving us the size of the FIFO */
+ cdns_spi_write(xspi, CDNS_SPI_THLD, 0xffff);
+ xspi->tx_fifo_depth = cdns_spi_read(xspi, CDNS_SPI_THLD) + 1;
+
+ /* Reset to default */
+ cdns_spi_write(xspi, CDNS_SPI_THLD, 0x1);
+}
+
+/**
* cdns_spi_probe - Probe method for the SPI driver
* @pdev: Pointer to the platform_device structure
*
@@ -535,6 +558,8 @@ static int cdns_spi_probe(struct platform_device *pdev)
if (ret < 0)
xspi->is_decoded_cs = 0;
+ cdns_spi_detect_fifo_depth(xspi);
+
/* SPI controller initializations */
cdns_spi_init_hw(xspi);