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)