[PATCH V2 1/2] spi: dual and quad support(device tree)

[Gupta, Pekon]

> 
> fix two things in patch:
> commit id:f477b7fb13df2b843997559ff34e87d054ba6538
> 
> 1.change the name of property: spi-tx-nbits and spi-rx-nbits to
> spi-tmax-nbits and spi-rmax-nbits, aimed to make that name different
> from the member of spi_transfer(tx_nbits and rx_nbits). using tmax
> and rmax here to describe that it is the max transfer bits that the
> members in spi_transfer(tx_nbits and rx_nbits) can reach.
> 2.change property spi-tmax-nbits and spi-rmax-nbits to optional.
> If User don't set spi-tmax-nbits or spi-rmax-nbits, spi device mode
> should be regarded as SINGLE, not return an error. In such case, user
> don't have to modify the old dts files to fit the new spi framework.
> 
> Signed-off-by: wangyuhang <wangyuhang2014 at gmail.com>
> ---
>  drivers/spi/spi.c |   72 +++++++++++++++++++++++++--------------------------
> --
>  1 file changed, 34 insertions(+), 38 deletions(-)
> 
> diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
> index 50f7fc3..8d191f2 100644
> --- a/drivers/spi/spi.c
> +++ b/drivers/spi/spi.c
> @@ -870,48 +870,44 @@ static void of_register_spi_devices(struct
> spi_master *master)
>  			spi->mode |= SPI_3WIRE;
> 
>  		/* Device DUAL/QUAD mode */
> -		prop = of_get_property(nc, "spi-tx-nbits", &len);
> +		prop = of_get_property(nc, "spi-tmax-nbits", &len);
>  		if (!prop || len < sizeof(*prop)) {
> -			dev_err(&master->dev, "%s has no 'spi-tx-nbits'
> property\n",
> -				nc->full_name);
> -			spi_dev_put(spi);
> -			continue;
> -		}
> -		switch (be32_to_cpup(prop)) {
> -		case SPI_NBITS_SINGLE:
> -			break;
> -		case SPI_NBITS_DUAL:
> -			spi->mode |= SPI_TX_DUAL;
> -			break;
> -		case SPI_NBITS_QUAD:
> -			spi->mode |= SPI_TX_QUAD;
> -			break;
> -		default:
> -			dev_err(&master->dev, "spi-tx-nbits value is not
> supported\n");
> -			spi_dev_put(spi);
> -			continue;
> +			/* set tx mode in SINGLE as default */
> +		} else {
> +			switch (be32_to_cpup(prop)) {
> +			case SPI_NBITS_SINGLE:
> +				break;
> +			case SPI_NBITS_DUAL:
> +				spi->mode |= SPI_TX_DUAL;
> +				break;
> +			case SPI_NBITS_QUAD:
> +				spi->mode |= SPI_TX_QUAD;
> +				break;
> +			default:
> +				dev_err(&master->dev,
> +					"spi-tmax-nbits value is not
> supported\n");
> +				spi_dev_put(spi);
> +				continue;
>  		}
> 
> -		prop = of_get_property(nc, "spi-rx-nbits", &len);
> +		prop = of_get_property(nc, "spi-rmax-nbits", &len);
>  		if (!prop || len < sizeof(*prop)) {
> -			dev_err(&master->dev, "%s has no 'spi-rx-nbits'
> property\n",
> -				nc->full_name);
> -			spi_dev_put(spi);
> -			continue;
> -		}
> -		switch (be32_to_cpup(prop)) {
> -		case SPI_NBITS_SINGLE:
> -			break;
> -		case SPI_NBITS_DUAL:
> -			spi->mode |= SPI_RX_DUAL;
> -			break;
> -		case SPI_NBITS_QUAD:
> -			spi->mode |= SPI_RX_QUAD;
> -			break;
> -		default:
> -			dev_err(&master->dev, "spi-rx-nbits value is not
> supported\n");
> -			spi_dev_put(spi);
> -			continue;
> +			/* set rx mode in SINGLE as default */
> +		} else {
> +			switch (be32_to_cpup(prop)) {
> +			case SPI_NBITS_SINGLE:
> +				break;
> +			case SPI_NBITS_DUAL:
> +				spi->mode |= SPI_RX_DUAL;
> +				break;
> +			case SPI_NBITS_QUAD:
> +				spi->mode |= SPI_RX_QUAD;
> +				break;
> +			default:
> +				dev_err(&master->dev,
> +					"spi-rmax-nbits value is not
> supported\n");
> +				spi_dev_put(spi);
> +				continue;
>  		}
> 
>  		/* Device speed */
> --
> 1.7.9.5

You missed out comments provided earlier..
http://lists.infradead.org/pipermail/linux-mtd/2013-August/048374.html

Remember .. this compatibility check is between spi_device->mode
v/s spi_master->mode_bits. This is different from ur V3 patch
which checks for spi_transfer->tx_nbits v/s spi_device->mode.

+ if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
+ !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
+ return -EINVAL;
+ if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
+ !(spi->mode & SPI_TX_QUAD))
+ return -EINVAL;


with regards, pekon