[U-Boot] [PATCH V3 3/4] dm: spi: introduce dm api

[Peng Fan <van.freenix@gmail.com>]

Introduce dm_spi_claim_bus, dm_spi_release_bus and dm_spi_xfer

Signed-off-by: Peng Fan <van.freenix@gmail.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: Jagan Teki <jteki@openedev.com>
---

V3:
 As Simon suggested, introduce new API. New patch.

 drivers/spi/spi-uclass.c | 48 ++++++++++++++++++++++++++++++++++++++++++++
 include/spi.h            | 52 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 100 insertions(+)

diff --git a/drivers/spi/spi-uclass.c b/drivers/spi/spi-uclass.c
index 5561f36..b2e0c46 100644
--- a/drivers/spi/spi-uclass.c
+++ b/drivers/spi/spi-uclass.c
@@ -45,6 +45,54 @@ static int spi_set_speed_mode(struct udevice *bus, int speed, int mode)
 	return 0;
 }
 
+int dm_spi_claim_bus(struct udevice *dev)
+{
+	struct udevice *bus = dev->parent;
+	struct dm_spi_ops *ops = spi_get_ops(bus);
+	struct dm_spi_bus *spi = dev_get_uclass_priv(bus);
+	struct spi_slave *slave = dev_get_parent_priv(dev);
+	int speed;
+	int ret;
+
+	speed = slave->max_hz;
+	if (spi->max_hz) {
+		if (speed)
+			speed = min(speed, (int)spi->max_hz);
+		else
+			speed = spi->max_hz;
+	}
+	if (!speed)
+		speed = 100000;
+	if (speed != slave->speed) {
+		ret = spi_set_speed_mode(bus, speed, slave->mode);
+		if (ret)
+			return ret;
+		slave->speed = speed;
+	}
+
+	return ops->claim_bus ? ops->claim_bus(dev) : 0;
+}
+
+void dm_spi_release_bus(struct udevice *dev)
+{
+	struct udevice *bus = dev->parent;
+	struct dm_spi_ops *ops = spi_get_ops(bus);
+
+	if (ops->release_bus)
+		ops->release_bus(dev);
+}
+
+int dm_spi_xfer(struct udevice *dev, unsigned int bitlen,
+		const void *dout, void *din, unsigned long flags)
+{
+	struct udevice *bus = dev->parent;
+
+	if (bus->uclass->uc_drv->id != UCLASS_SPI)
+		return -EOPNOTSUPP;
+
+	return spi_get_ops(bus)->xfer(dev, bitlen, dout, din, flags);
+}
+
 int spi_claim_bus(struct spi_slave *slave)
 {
 	struct udevice *dev = slave->dev;
diff --git a/include/spi.h b/include/spi.h
index 4b88d39..ca96fa4 100644
--- a/include/spi.h
+++ b/include/spi.h
@@ -612,6 +612,58 @@ int sandbox_spi_get_emul(struct sandbox_state *state,
 			 struct udevice *bus, struct udevice *slave,
 			 struct udevice **emulp);
 
+/**
+ * Claim the bus and prepare it for communication with a given slave.
+ *
+ * This must be called before doing any transfers with a SPI slave. It
+ * will enable and initialize any SPI hardware as necessary, and make
+ * sure that the SCK line is in the correct idle state. It is not
+ * allowed to claim the same bus for several slaves without releasing
+ * the bus in between.
+ *
+ * @dev:	The SPI slave device
+ *
+ * Returns: 0 if the bus was claimed successfully, or a negative value
+ * if it wasn't.
+ */
+int dm_spi_claim_bus(struct udevice *dev);
+
+/**
+ * Release the SPI bus
+ *
+ * This must be called once for every call to dm_spi_claim_bus() after
+ * all transfers have finished. It may disable any SPI hardware as
+ * appropriate.
+ *
+ * @slave:	The SPI slave device
+ */
+void dm_spi_release_bus(struct udevice *dev);
+
+/**
+ * SPI transfer
+ *
+ * This writes "bitlen" bits out the SPI MOSI port and simultaneously clocks
+ * "bitlen" bits in the SPI MISO port.  That's just the way SPI works.
+ *
+ * The source of the outgoing bits is the "dout" parameter and the
+ * destination of the input bits is the "din" parameter.  Note that "dout"
+ * and "din" can point to the same memory location, in which case the
+ * input data overwrites the output data (since both are buffered by
+ * temporary variables, this is OK).
+ *
+ * dm_spi_xfer() interface:
+ * @dev:	The SPI slave device which will be sending/receiving the data.
+ * @bitlen:	How many bits to write and read.
+ * @dout:	Pointer to a string of bits to send out.  The bits are
+ *		held in a byte array and are sent MSB first.
+ * @din:	Pointer to a string of bits that will be filled in.
+ * @flags:	A bitwise combination of SPI_XFER_* flags.
+ *
+ * Returns: 0 on success, not 0 on failure
+ */
+int dm_spi_xfer(struct udevice *dev, unsigned int bitlen,
+		const void *dout, void *din, unsigned long flags);
+
 /* Access the operations for a SPI device */
 #define spi_get_ops(dev)	((struct dm_spi_ops *)(dev)->driver->ops)
 #define spi_emul_get_ops(dev)	((struct dm_spi_emul_ops *)(dev)->driver->ops)
-- 
2.6.2