On Mon, Aug 2, 2010 at 1:52 AM, Mingkai Hu <mingkai...@freescale.com> wrote:
> Add eSPI controller support based on the library code spi_fsl_lib.c.
>
> The eSPI controller is newer controller 85xx/Pxxx devices supported.
> There're some differences comparing to the SPI controller:
>
> 1. Has different register map and different bit definition
> So leave the code operated the register to the driver code, not
> the common code.
>
> 2. Support 4 dedicated chip selects
> The software can't controll the chip selects directly, The SPCOM[CS]
> field is used to select which chip selects is used, and the
> SPCOM[TRANLEN] field is set to tell the controller how long the CS
> signal need to be asserted. So the driver doesn't need the chipselect
> related function when transfering data, just set corresponding register
> fields to controll the chipseclect.
>
> 3. Different Transmit/Receive FIFO access register behavior
> For SPI controller, the Tx/Rx FIFO access register can hold only
> one character regardless of the character length, but for eSPI
> controller, the register can hold 4 or 2 characters according to
> the character lengths. Access the Tx/Rx FIFO access register of the
> eSPI controller will shift out/in 4/2 characters one time. For SPI
> subsystem, the command and data are put into different transfers, so
> we need to combine all the transfers to one transfer in order to pass
> the transfer to eSPI controller.
>
> Signed-off-by: Mingkai Hu <mingkai...@freescale.com>
I've not dug deep into this patch, but it seems pretty good. I did
notice one thing below...
[...]
> diff --git a/drivers/spi/spi_fsl_lib.h b/drivers/spi/spi_fsl_lib.h
> index 774e1c8..0772c98 100644
> --- a/drivers/spi/spi_fsl_lib.h
> +++ b/drivers/spi/spi_fsl_lib.h
> @@ -22,10 +22,12 @@
> struct mpc8xxx_spi {
> struct device *dev;
> struct fsl_spi_reg __iomem *base;
> + struct fsl_espi_reg __iomem *espi_base;
There's got to be a cleaner way to do this. Rather than putting both
pointers into mpc8xxx_spi, I suggest each driver use its own
fsl_spi_priv and fsl_espi_priv wrapper structures that contain the
controller specific properties.
cheers,
g.
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