2011-06-15 04:04:49     mmc_spi and two chips on the spi bus.

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2011-06-15 04:04:49     mmc_spi and two chips on the spi bus.

Dimitar Penev (BULGARIA)

Message: 101278   

 

Hi Guys,

 

I've noticed that the mmc_spi driver in 2010R1-RC5 doesn't suport two chips on the SPI bus.

I've saw that there is a pacth for this in the GIT called "move to mainline SPI locking API"

 

However applying it on 2010R1-RC5 seems to make our board unstable.

It seems it influence our nand flash as well somehow.

I have not investigated further, fortunately the second chip on the SPI bus is not inportant for us right now but still.

 

Is theer somone using mmc_spi with few chips on the same SPI bus based on 2010R1-RC5 distribution?

 

Thanks

Dimitar

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2011-06-15 04:50:56     Re: mmc_spi and two chips on the spi bus.

Sonic Zhang (CHINA)

Message: 101281   

 

That patch has nothing to do with your 2010R1-RC5 release. It is against kernel mainline tree.

 

Don't forget to select option "SPI Bus lock" under "SPI controller driver for ADI Blackfin" in your case.

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2011-06-15 07:51:22     Re: mmc_spi and two chips on the spi bus.

Dimitar Penev (BULGARIA)

Message: 101284   

 

Hi Sonic,

 

Having two SPI chips on the same bus confgured I got in the system log

mmc_spi spi0: can't share SPI bus

 

Based on this and what I have seen already discussed in the forum I concluded that the mmc_spi driver in the 2010R1-RC5

doesn't support SD card and another SPI chip sharing the SPI bus.

 

Does it mean I got confused and I will be OK if enable "SPI Bus lock".

And I don't need to patch anything?

 

Thanks

Dimitar

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2011-06-15 22:43:20     Re: mmc_spi and two chips on the spi bus.

Aaron Wu (CHINA)

Message: 101292   

 

Yes, no patch needed, please enable the "SPI Bus lock" as Sonic said and share us the feedback.

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2011-06-17 06:09:03     Re: mmc_spi and two chips on the spi bus.

Dimitar Penev (BULGARIA)

Message: 101380   

 

Hi Guys,

 

Thank you for the help!

 

Meanwhile I have noticed that I was using wrong SPI_MODE so I was reading garbage from the SD-card which the driver accepted happily.

 

I am curious why Linux driver doesn't confirm the CRC for the CSD data which standard defines.

 

Thanks

Dimitar

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2011-06-17 12:32:34     Re: mmc_spi and two chips on the spi bus.

Mike Frysinger (UNITED STATES)

Message: 101390   

 

that'd probably be a question to post to the linux-mmc@vger.kernel.org mailing list

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