diff options
| -rw-r--r-- | drivers/spi/spi-uclass.c | 24 | ||||
| -rw-r--r-- | include/spi.h | 20 |
2 files changed, 44 insertions, 0 deletions
diff --git a/drivers/spi/spi-uclass.c b/drivers/spi/spi-uclass.c index 88cb2a12622..76c4b53c165 100644 --- a/drivers/spi/spi-uclass.c +++ b/drivers/spi/spi-uclass.c @@ -108,6 +108,30 @@ int spi_xfer(struct spi_slave *slave, unsigned int bitlen, return dm_spi_xfer(slave->dev, bitlen, dout, din, flags); } +int spi_write_then_read(struct spi_slave *slave, const u8 *opcode, + size_t n_opcode, const u8 *txbuf, u8 *rxbuf, + size_t n_buf) +{ + unsigned long flags = SPI_XFER_BEGIN; + int ret; + + if (n_buf == 0) + flags |= SPI_XFER_END; + + ret = spi_xfer(slave, n_opcode * 8, opcode, NULL, flags); + if (ret) { + debug("spi: failed to send command (%zu bytes): %d\n", + n_opcode, ret); + } else if (n_buf != 0) { + ret = spi_xfer(slave, n_buf * 8, txbuf, rxbuf, SPI_XFER_END); + if (ret) + debug("spi: failed to transfer %zu bytes of data: %d\n", + n_buf, ret); + } + + return ret; +} + #if !CONFIG_IS_ENABLED(OF_PLATDATA) static int spi_child_post_bind(struct udevice *dev) { diff --git a/include/spi.h b/include/spi.h index 378594163b8..5eec0c4775e 100644 --- a/include/spi.h +++ b/include/spi.h @@ -248,6 +248,26 @@ int spi_set_wordlen(struct spi_slave *slave, unsigned int wordlen); int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout, void *din, unsigned long flags); +/** + * spi_write_then_read - SPI synchronous write followed by read + * + * This performs a half duplex transaction in which the first transaction + * is to send the opcode and if the length of buf is non-zero then it start + * the second transaction as tx or rx based on the need from respective slave. + * + * @slave: The SPI slave device with which opcode/data will be exchanged + * @opcode: opcode used for specific transfer + * @n_opcode: size of opcode, in bytes + * @txbuf: buffer into which data to be written + * @rxbuf: buffer into which data will be read + * @n_buf: size of buf (whether it's [tx|rx]buf), in bytes + * + * Returns: 0 on success, not 0 on failure + */ +int spi_write_then_read(struct spi_slave *slave, const u8 *opcode, + size_t n_opcode, const u8 *txbuf, u8 *rxbuf, + size_t n_buf); + /* Copy memory mapped data */ void spi_flash_copy_mmap(void *data, void *offset, size_t len); |