diff options
| -rw-r--r-- | drivers/spi/spi-dw-core.c | 40 |
1 files changed, 39 insertions, 1 deletions
diff --git a/drivers/spi/spi-dw-core.c b/drivers/spi/spi-dw-core.c index bcfa224e0e43..2e50cc0a9291 100644 --- a/drivers/spi/spi-dw-core.c +++ b/drivers/spi/spi-dw-core.c @@ -364,6 +364,42 @@ static void dw_spi_irq_setup(struct dw_spi *dws) dws->transfer_handler = dw_spi_transfer_handler; } +/* + * The iterative procedure of the poll-based transfer is simple: write as much + * as possible to the Tx FIFO, wait until the pending to receive data is ready + * to be read, read it from the Rx FIFO and check whether the performed + * procedure has been successful. + * + * Note this method the same way as the IRQ-based transfer won't work well for + * the SPI devices connected to the controller with native CS due to the + * automatic CS assertion/de-assertion. + */ +static int dw_spi_poll_transfer(struct dw_spi *dws, + struct spi_transfer *transfer) +{ + struct spi_delay delay; + u16 nbits; + int ret; + + delay.unit = SPI_DELAY_UNIT_SCK; + nbits = dws->n_bytes * BITS_PER_BYTE; + + do { + dw_writer(dws); + + delay.value = nbits * (dws->rx_len - dws->tx_len); + spi_delay_exec(&delay, transfer); + + dw_reader(dws); + + ret = dw_spi_check_status(dws, true); + if (ret) + return ret; + } while (dws->rx_len); + + return 0; +} + static int dw_spi_transfer_one(struct spi_controller *master, struct spi_device *spi, struct spi_transfer *transfer) { @@ -408,6 +444,8 @@ static int dw_spi_transfer_one(struct spi_controller *master, if (dws->dma_mapped) return dws->dma_ops->dma_transfer(dws, transfer); + else if (dws->irq == IRQ_NOTCONNECTED) + return dw_spi_poll_transfer(dws, transfer); dw_spi_irq_setup(dws); @@ -817,7 +855,7 @@ int dw_spi_add_host(struct device *dev, struct dw_spi *dws) ret = request_irq(dws->irq, dw_spi_irq, IRQF_SHARED, dev_name(dev), master); - if (ret < 0) { + if (ret < 0 && ret != -ENOTCONN) { dev_err(dev, "can not get IRQ\n"); goto err_free_master; } |