spi: add SPI controller driver for UniPhier SoC

Add SPI controller driver implemented in Socionext UniPhier SoCs.

UniPhier SoCs have two types SPI controllers; SCSSI supports a
single channel, and MCSSI supports multiple channels.
This driver supports SCSSI only.

This controller has 32bit TX/RX FIFO with depth of eight entry,
and supports the SPI master mode only.

This commit is implemented in PIO transfer mode, not DMA transfer.

Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Signed-off-by: Keiji Hayashibara <hayashibara.keiji@socionext.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 13 insertions, 0 deletions

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index ad5d68e1dab7..671d078349cc 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -688,6 +688,19 @@ config SPI_TXX9
         help
           SPI driver for Toshiba TXx9 MIPS SoCs
 
+config SPI_UNIPHIER
+        tristate "Socionext UniPhier SPI Controller"
+        depends on (ARCH_UNIPHIER || COMPILE_TEST) && OF
+        help
+          This enables a driver for the Socionext UniPhier SoC SCSSI SPI controller.
+
+          UniPhier SoCs have SCSSI and MCSSI SPI controllers.
+          Every UniPhier SoC has SCSSI which supports single channel.
+          Older UniPhier Pro4/Pro5 also has MCSSI which support multiple channels.
+          This driver supports SCSSI only.
+
+          If your SoC supports SCSSI, say Y here.
+
 config SPI_XCOMM
         tristate "Analog Devices AD-FMCOMMS1-EBZ SPI-I2C-bridge driver"
         depends on I2C