spi_mpc8xxx.c: chip select polarity problem

Torsten Fleischer to-fleischer at t-online.de
Wed Nov 18 07:09:28 EST 2009


On Mon, Nov 16, 2009 at 19:00PM, Anton Vorontsov wrote:
[...]
> > So it might be better to fix up initial value in the platform code?
> 
> Oh, we actually cannot, because the driver calls
> gpio_direction_output().
> 
> And since we don't know the mode prior to SPI device's driver
> probe() finished, we'll have to set up an initial state in the
> first SPI transfer. I.e. something like this:

In most cases the device drivers perform SPI transfers already in their 
probe() function. How can it be ensured that the CS of all other devices are 
inactive even if they are not initialized at that time?

Regards
Torsten Fleischer


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