On Thu, 8 May 2008, Haavard Skinnemoen wrote:
> > I thought, like (pseudocode)
> >
> > static struct spi_host busses[SPI_BUSSES];
> >
> > struct spi_slave *spi_init()
> > {
> > list_for_each_entry(slave, &busses[bus].slaves, list) {
> > if (slave->device == device)
> > return (struct spi_slave *)-EBUSY;
> > }
> > slave = malloc();
> > slave->bus = bus;
> > slave->device = device;
> > ret = busses[bus].init(slave);
> > if (ret) {
> > free(slave);
> > return (struct spi_slave *)ret;
> > }
> > return slave;
> > }
> >
> > int spi_xfer()
> > {
> > list_for_each_entry(ix, &busses[bus].slaves, list) {
> > if (ix == slave)
> > break;
> > }
> > if (ix != slave)
> > return -EINVAL;
> >
> > if (slave->bus->busy)
> > return -EBUSY;
> >
> > return slave->bus->xfer();
> > }
>
> I was thinking about something much simpler:
>
> struct spi_slave *spi_init_slave(bus, cs, max_hz, mode)
> {
> slave = malloc();
> slave->regs = get_spi_controller_base_address(bus);
> slave->mode_reg = get_suitable_settings_for(cs, max_hz, mode);
> return slave;
> }
>
> int spi_xfer(slave, ...)
> {
> __raw_writel(slave->mode_reg, slave->regs + SPI_MR);
> if (flags & SPI_XFER_BEGIN)
> assert_chip_select();
>
> do_the_actual_spi_transfer();
>
> if (flags & SPI_XFER_END)
> deassert_chip_select();
>
> return whatever;
> }
>
> Of course, your solution will work with multiple, different SPI
> controllers while mine won't, but is that really necessary?
>
> Your solution comes with more error checking as well, which might be a
> good thing, but since it comes with a cost of additional memory and
> flash footprint, I think it should be optional. Maybe we could provide
> some library functions to simplify the drivers that want this?
I see. Well, I don't have a strong preference. So, either we need more
votes, or the one who implements it decides:-)
Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-0 Fax: +49-8142-66989-80 Email: [EMAIL PROTECTED]
-------------------------------------------------------------------------
This SF.net email is sponsored by the 2008 JavaOne(SM) Conference
Don't miss this year's exciting event. There's still time to save $100.
Use priority code J8TL2D2.
http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone
_______________________________________________
U-Boot-Users mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/u-boot-users
