spi: Define and use spi_ctrlr structure

1. Define a new structure spi_ctrlr that allows platforms to define
callbacks for spi operations (claim bus, release bus, transfer).
2. Add a new member (pointer to spi_ctrlr structure) in spi_slave
structure which will be initialized by call to spi_setup_slave.
3. Define spi_claim_bus, spi_release_bus and spi_xfer in spi-generic.c
which will make appropriate calls to ctrlr functions.

BUG=chrome-os-partner:59832
BRANCH=None
TEST=Compiles successfully

Change-Id: Icb2326e3aab1e8f4bef53f553f82b3836358c55e
Signed-off-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: https://review.coreboot.org/17684
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

1 files changed, 18 insertions, 0 deletions

diff --git a/src/include/spi-generic.h b/src/include/spi-generic.h
index c8b209da21..b4a10af0c0 100644
--- a/src/include/spi-generic.h
+++ b/src/include/spi-generic.h
@@ -21,15 +21,33 @@
 
 /* Controller-specific definitions: */
 
+struct spi_ctrlr;
+
 /*-----------------------------------------------------------------------
  * Representation of a SPI slave, i.e. what we're communicating with.
  *
  *   bus:	ID of the bus that the slave is attached to.
  *   cs:	ID of the chip select connected to the slave.
+ *   ctrlr:	Pointer to SPI controller structure.
  */
 struct spi_slave {
 	unsigned int	bus;
 	unsigned int	cs;
+	const struct spi_ctrlr *ctrlr;
+};
+
+/*-----------------------------------------------------------------------
+ * Representation of a SPI contoller.
+ *
+ * claim_bus:	Claim SPI bus and prepare for communication.
+ * release_bus: Release SPI bus.
+ * xfer:	SPI transfer
+ */
+struct spi_ctrlr {
+	int (*claim_bus)(const struct spi_slave *slave);
+	void (*release_bus)(const struct spi_slave *slave);
+	int (*xfer)(const struct spi_slave *slave, const void *dout,
+		    size_t bytesout, void *din, size_t bytesin);
 };
 
 /*-----------------------------------------------------------------------