Re: [RFC/PATCH 3/3] driver: spi: Add quad spi read support

Felipe Balbi
2013-07-08T14:37:18Z

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On Mon, Jul 08, 2013 at 07:13:00PM +0530, Sourav Poddar wrote:
> Since, qspi controller uses quad read.
>
> Configuring the command register, if the transfer of data needs
> quad lines.
>
> This patch has been done on top of the following patch[1], which is still
> under review/comments.
> This patch will also go changes, as the parent patch[1] does.
>
> [1]: http://comments.gmane.org/gmane.linux.kernel.spi.devel/14047
>
> Signed-off-by: Sourav Poddar <sourav.poddar@ti.com>
> ---
> drivers/spi/spi-ti-qspi.c | 8 ++++++--
> 1 files changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/spi/spi-ti-qspi.c b/drivers/spi/spi-ti-qspi.c
> index 430de9c..307cbed 100644
> --- a/drivers/spi/spi-ti-qspi.c
> +++ b/drivers/spi/spi-ti-qspi.c
> @@ -258,8 +258,12 @@ static int qspi_read_msg(struct dra7xxx_qspi *qspi, struct spi_transfer *t)
> qspi->cmd | QSPI_RD_SNGL, qspi->dc);
> dra7xxx_writel(qspi, QSPI_WC_INT_EN, QSPI_INTR_ENABLE_SET_REG);
> dra7xxx_writel(qspi, qspi->dc, QSPI_SPI_DC_REG);
> - dra7xxx_writel(qspi, qspi->cmd | QSPI_RD_SNGL,
> - QSPI_SPI_CMD_REG);
> + if (t->bitwidth == SPI_BITWIDTH_QUAD)
> + dra7xxx_writel(qspi, qspi->cmd | QSPI_RD_QUAD,
> + QSPI_SPI_CMD_REG);
> + else
> + dra7xxx_writel(qspi, qspi->cmd | QSPI_RD_SNGL,
> + QSPI_SPI_CMD_REG);

we also have read dual, in order to make this code a little better you
could:

unsigned cmd = qspi->cmd;

switch (t->bitwidth)
case SPI_BITWIDTH_QUAD:
cmd |= QSPI_RD_QUAD;
break;
case SPI_BITWIDTH_DUAL:
cmd |= QSPI_RD_DUAL;
break;
case SPI_BITWIDTH_SINGLE:
default:
cmd |= QSPI_RD_SNGL;
}

dra7xx_writel(qspi, cmd, QSPI_SPI_CMD_REG);

--
balbi

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