Em 21-09-2011 09:38, Rajashekhara, Sudhakar escreveu:
Hi,
On Wed, Aug 31, 2011 at 17:47:43, Aníbal Almeida Pinto wrote:
Hi,
I am using the OMAP L138 logic evaluation board with 3.0.0 linux-davinci
kernel.
To the default configuration I have added spi support and build the
spi_davinci as a module.
After the boards boot I was able to insmod davinci_spi.ko but when tried
to make rmmod davinci_spi.ko the board halted.
Anyone have reported this ?
Inserting printk on davinci_spi remove function it appears to be on
clk_disable.
I also noticed this issue. When I debugged this I found out that, the
SPI driver enables the local low-power mode. This is achieved by setting
the POWERDOWN bit (9th bit) in SPIGCR1 register.
In local low-power mode, clock to SPI internal logic is stopped. At this
point of time, doing a clk_disable() is not behaving properly. When SPI
is not in low-power mode, clk_disable() works fine. So for rmmod to work,
you need to remove all references to SPIGCR1_POWERDOWN_MASK in the code.
Please test this at your end and let me know the outcome. If it is working,
then I can submit a patch to the list which takes care of this.
If I apply the patch attached I can make rmmod of the spi davinci driver.
The procedure that I have tested :
# insmod davinci_spi.ko
spi_davinci spi_davinci.1: DMA: supported
spi_davinci spi_davinci.1: DMA: RX channel: 18, TX channel: 19, event
queue: 0
spi_davinci spi_davinci.1: Controller at 0xfef0e000
# rmmod davinci_spi.ko
But can't insmod it again :
# insmod davinci_spi.ko
Unable to request DMA channel for SPI RX
Trying to free nonexistent resource <0000000001f0e000-0000000001f0e000>
spi_davinci: probe of spi_davinci.1 failed with error -11
insmod: can't insert 'davinci_spi.ko': No such device
Thanks,
Sudhakar
554c554
< // clear_io_bits(dspi->base + SPIGCR1, SPIGCR1_POWERDOWN_MASK);
---
> clear_io_bits(dspi->base + SPIGCR1, SPIGCR1_POWERDOWN_MASK);
705c705
< // set_io_bits(dspi->base + SPIGCR1, SPIGCR1_POWERDOWN_MASK);
---
> set_io_bits(dspi->base + SPIGCR1, SPIGCR1_POWERDOWN_MASK);
947c947
< // set_io_bits(dspi->base + SPIGCR1, SPIGCR1_POWERDOWN_MASK);
---
> set_io_bits(dspi->base + SPIGCR1, SPIGCR1_POWERDOWN_MASK);
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