On Wed, Dec 07, 2016 at 05:19:57PM +0100, Romain Perier wrote:
> Le 05/12/2016 à 14:37, Mark Brown a écrit :
> > Why? If the hardware supports a more efficient mode of operation it
> > doesn't seem sensible not to use it.
> That's just that our customer want to keep both modes, this is why I decided
> to use the more efficient mode by default and disable it via a module
> parameter. Previously the more efficient mode was always enabled, based on
> the "compatible string" of the DT (the PIO mode was simply useless in this
> case and dead code)
Keep that out of tree, if the user wants to do silly things then let
them pay the cost.
> > > + if (xfer->rx_buf) {
> > > + /* Set read data length */
> > > + spireg_write(a3700_spi, A3700_SPI_IF_DIN_CNT_REG,
> > > + a3700_spi->buf_len);
> > > + /* Start READ transfer */
> > > + val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
> > > + val &= ~A3700_SPI_RW_EN;
> > > + val |= A3700_SPI_XFER_START;
> > > + spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
> > > + } else if (xfer->tx_buf) {
> > > + /* Start Write transfer */
> > So this only supports single duplex transfers but there doesn't seem to
> > be anything that enforces this.
> A flag or a capability, typically? I will investigate
SPI_MASTER_HALF_DUPLEX.
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