On Wed, 4 Feb 2009, Jean-Christophe PLAGNIOL-VILLARD wrote:
> On 17:59 Wed 04 Feb , Guennadi Liakhovetski wrote:
> >
> > + /*
> > + * Some SPI devices require active chip-select over multiple
> > + * transactions, we achieve this using a GPIO. Still, the SPI
> > + * controller has to be configured to use one of its own chipselects.
> > + * To use this feature you have to call spi_setup_slave() with
> > + * cs = internal_cs | (gpio << 8), and you have to use some unused
> > + * on this SPI controller cs between 0 and 3.
> > + */
> > + if (cs > 3) {
> > + mxcs->gpio = cs >> 8;
> > + cs &= 3;
> > + mx31_gpio_direction(mxcs->gpio, MX31_GPIO_DIRECTION_OUT);
> > + } else
> > + mxcs->gpio = -1;
> > +
> why not add a callback for the chipselect instead
> as example if you have to use a gpio extender it will simplest to implent
> instead of hack the SPI driver
and how shall I pass this callback to
struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
unsigned int max_hz, unsigned int mode)
?
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: off...@denx.de
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