SPI and spi_cs_activate

I am trying to get the spi_mmc driver by Robert Selberg and Hans Eklund to run on my new Coldfire board. (The driver was posted as a patch some time ago, clearly marked as not ready for mainline. I just did not figure out the correct search term to give the message ID.)

Now I am running into problems because the driver uses spi_cs_[de]activate, which is rather useless on coldfire which does automatic cs.

Looking through other drivers' code it seems to me that spi_cs_[de]activate was never meant to be called from anybody else but some special SPI drivers that can not aotumatically control cs lines or for systems where SPI is done in software and so setting the appropriate GPIOs is handed over to special board-dependent code.

Quoted 8 lines · On Friday 29 January 2010 10:59:28 Wolfgang Wegner wrote:

I am trying to get the spi_mmc driver by Robert Selberg and Hans Eklund to run on my new Coldfire board. (The driver was posted as a patch some time ago, clearly marked as not ready for mainline. I just did not figure out the correct search term to give the message ID.)

Now I am running into problems because the driver uses spi_cs_[de]activate, which is rather useless on coldfire which does automatic cs.

Quoted 5 lines

Looking through other drivers' code it seems to me that spi_cs_[de]activate was never meant to be called from anybody else but some special SPI drivers that can not aotumatically control cs lines or for systems where SPI is done in software and so setting the appropriate GPIOs is handed over to special board-dependent code.

there are plenty of SPI controllers which allow the CS to be manually controlled. this isnt a "special" driver.

the MMC/SPI driver was written on a Blackfin system. it working on any other system is coincidental as a result of leveraging the common frameworks. feel free to submit fixes.

Quoted 16 lines · Mike Frysinger

Quoted 14 lines · On Friday 29 January 2010 10:59:28 Wolfgang Wegner wrote:

I am trying to get the spi_mmc driver by Robert Selberg and Hans Eklund to run on my new Coldfire board. (The driver was posted as a patch some time ago, clearly marked as not ready for mainline. I just did not figure out the correct search term to give the message ID.)

Now I am running into problems because the driver uses spi_cs_[de]activate, which is rather useless on coldfire which does automatic cs.

Looking through other drivers' code it seems to me that spi_cs_[de]activate was never meant to be called from anybody else but some special SPI drivers that can not aotumatically control cs lines or for systems where SPI is done in software and so setting the appropriate GPIOs is handed over to special board-dependent code.

Quoted 2 lines

there are plenty of SPI controllers which allow the CS to be manually controlled. this isnt a "special" driver.

OK, of course controlling CS manually is possible on most systems (via GPIO). What I meant is that most systems do not care to control it automatically (mostly for complexity reasons or because of real HW limitations, as far as I understand).

Quoted 3 lines

the MMC/SPI driver was written on a Blackfin system. it working on any other system is coincidental as a result of leveraging the common frameworks. feel free to submit fixes.

This is my intention in case I understand in which direction I have to fix. (And in case I then get it to work in such a way, of course.)

Are all SPI drivers supposed to supply functions to manually control the CS lines?

If so, what means shall be provided to disable automatic control?