This adds SPI support for the Sparx5 SoC, which is using the MMIO
Designware SPI controller.
The Sparx5 differs from the Ocelot version in these areas:
* The CS override is controlled by a new set of registers for
this purpose.
* The Sparx5 SPI controller has the RX sample delay register, and it
must be configured for the (SPI NAND) device on SPI2.
* The Sparx5 SPI controller has 2 different SPI bus interfaces on the
same controller (don't ask...). The "spi-mux" driver should be used
in conjunction with the SPI driver to select the appropriate bus.
Signed-off-by: Lars Povlsen <lars.povlsen@xxxxxxxxxxxxx>
---
drivers/spi/spi-dw-mmio.c | 70 ++++++++++++++++++++++++++++++++++++++-
1 file changed, 69 insertions(+), 1 deletion(-)
diff --git a/drivers/spi/spi-dw-mmio.c b/drivers/spi/spi-dw-mmio.c
index 403403deae66..18772c0c9220 100644
--- a/drivers/spi/spi-dw-mmio.c
+++ b/drivers/spi/spi-dw-mmio.c
@@ -45,6 +45,9 @@ struct dw_spi_mmio {
#define MSCC_SPI_MST_SW_MODE_SW_PIN_CTRL_MODE BIT(13)
#define MSCC_SPI_MST_SW_MODE_SW_SPI_CS(x) (x << 5)
+#define SPARX5_FORCE_ENA 0xa4
+#define SPARX5_FORCE_VAL 0xa8
+
/*
* For Keem Bay, CTRLR0[31] is used to select controller mode.
* 0: SSI is slave
@@ -54,7 +57,7 @@ struct dw_spi_mmio {
struct dw_spi_mscc {
struct regmap *syscon;
- void __iomem *spi_mst;
+ void __iomem *spi_mst; /* Not sparx5 */
};
/*
@@ -134,6 +137,70 @@ static int dw_spi_mscc_jaguar2_init(struct platform_device *pdev,
JAGUAR2_IF_SI_OWNER_OFFSET);
}
+/*
+ * The Designware SPI controller (referred to as master in the
+ * documentation) automatically deasserts chip select when the tx fifo
+ * is empty. The chip selects then needs to be driven by a CS override
+ * register. enable is an active low signal.
+ */
+static void dw_spi_sparx5_set_cs(struct spi_device *spi, bool enable)
+{
+ struct dw_spi *dws = spi_master_get_devdata(spi->master);
+ struct dw_spi_mmio *dwsmmio = container_of(dws, struct dw_spi_mmio, dws);
+ struct dw_spi_mscc *dwsmscc = dwsmmio->priv;
+ u8 cs = spi->chip_select;
+
+ if (!enable) {
+ /* CS override drive enable */
+ regmap_write(dwsmscc->syscon, SPARX5_FORCE_ENA, 1);
+ /* Now set CSx enabled */
+ regmap_write(dwsmscc->syscon, SPARX5_FORCE_VAL, ~BIT(cs));
+ /* Allow settle */
+ usleep_range(1, 5);
+ } else {
+ /* CS value */
+ regmap_write(dwsmscc->syscon, SPARX5_FORCE_VAL, ~0);
+ /* Allow settle */
+ usleep_range(1, 5);
+ /* CS override drive disable */
+ regmap_write(dwsmscc->syscon, SPARX5_FORCE_ENA, 0);
+ }
+
+ dw_spi_set_cs(spi, enable);
+}
+
+static int dw_spi_mscc_sparx5_init(struct platform_device *pdev,
+ struct dw_spi_mmio *dwsmmio)
+{
+ const char *syscon_name = "microchip,sparx5-cpu-syscon";
+ struct device *dev = &pdev->dev;
+ struct dw_spi_mscc *dwsmscc;
+
+ if (!IS_ENABLED(CONFIG_SPI_MUX)) {
+ dev_err(dev, "This driver needs CONFIG_SPI_MUX\n");
+ return -EOPNOTSUPP;
+ }
+
+ dwsmscc = devm_kzalloc(dev, sizeof(*dwsmscc), GFP_KERNEL);
+ if (!dwsmscc)
+ return -ENOMEM;
+
+ dwsmscc->syscon =
+ syscon_regmap_lookup_by_compatible(syscon_name);
+ if (IS_ERR(dwsmscc->syscon)) {
+ dev_err(dev, "No syscon map %s\n", syscon_name);
+ return PTR_ERR(dwsmscc->syscon);
+ }
+
+ dwsmmio->dws.set_cs = dw_spi_sparx5_set_cs;
+ dwsmmio->priv = dwsmscc;
+
+ /* Register hook to configure CTRLR0 */
+ dwsmmio->dws.update_cr0 = dw_spi_update_cr0;
+
+ return 0;
+}
+
static int dw_spi_alpine_init(struct platform_device *pdev,
struct dw_spi_mmio *dwsmmio)
{
@@ -297,6 +364,7 @@ static const struct of_device_id dw_spi_mmio_of_match[] = {
{ .compatible = "renesas,rzn1-spi", .data = dw_spi_dw_apb_init},
{ .compatible = "snps,dwc-ssi-1.01a", .data = dw_spi_dwc_ssi_init},
{ .compatible = "intel,keembay-ssi", .data = dw_spi_keembay_init},
+ { .compatible = "microchip,sparx5-spi", dw_spi_mscc_sparx5_init},
{ /* end of table */}
};
MODULE_DEVICE_TABLE(of, dw_spi_mmio_of_match);
--
2.27.0
