Introduce dm_spi_claim_bus, dm_spi_release_bus and dm_spi_xfer
Signed-off-by: Peng Fan <[email protected]>
Cc: Simon Glass <[email protected]>
Cc: Jagan Teki <[email protected]>
---
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
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