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Subject[PATCH v2 03/13] spi: dw: Add support for Pensando Elba SoC SPI
Date
The Pensando Elba SoC uses a GPIO based chip select
for two DW SPI busses with each bus having two
chip selects.

Signed-off-by: Brad Larson <brad@pensando.io>
---
drivers/spi/spi-dw-mmio.c | 28 +++++++++++++++++++++++++++-
1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-dw-mmio.c b/drivers/spi/spi-dw-mmio.c
index 17c06039a74d..c323a5ceecb8 100644
--- a/drivers/spi/spi-dw-mmio.c
+++ b/drivers/spi/spi-dw-mmio.c
@@ -56,7 +56,7 @@ struct dw_spi_mscc {
/*
* 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 either driven as GPIOs or, for the first 4 using the
+ * selects then needs to be either driven as GPIOs or, for the first 4 using
* the SPI boot controller registers. the final chip select is an OR gate
* between the Designware SPI controller and the SPI boot controller.
*/
@@ -237,6 +237,31 @@ static int dw_spi_canaan_k210_init(struct platform_device *pdev,
return 0;
}

+static void dw_spi_elba_set_cs(struct spi_device *spi, bool enable)
+{
+ struct dw_spi *dws = spi_master_get_devdata(spi->master);
+
+ if (!enable) {
+ /*
+ * Using a GPIO-based chip-select, the DW SPI
+ * controller still needs its own CS bit selected
+ * to start the serial engine. On Elba the specific
+ * CS doesn't matter to start the serial engine,
+ * so using CS0.
+ */
+ dw_writel(dws, DW_SPI_SER, BIT(0));
+ } else {
+ dw_writel(dws, DW_SPI_SER, 0);
+ }
+}
+
+static int dw_spi_elba_init(struct platform_device *pdev,
+ struct dw_spi_mmio *dwsmmio)
+{
+ dwsmmio->dws.set_cs = dw_spi_elba_set_cs;
+ return 0;
+}
+
static int dw_spi_mmio_probe(struct platform_device *pdev)
{
int (*init_func)(struct platform_device *pdev,
@@ -351,6 +376,7 @@ static const struct of_device_id dw_spi_mmio_of_match[] = {
{ .compatible = "intel,keembay-ssi", .data = dw_spi_keembay_init},
{ .compatible = "microchip,sparx5-spi", dw_spi_mscc_sparx5_init},
{ .compatible = "canaan,k210-spi", dw_spi_canaan_k210_init},
+ { .compatible = "pensando,elba-spi", .data = dw_spi_elba_init},
{ /* end of table */}
};
MODULE_DEVICE_TABLE(of, dw_spi_mmio_of_match);
--
2.17.1
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