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From: Antony Pavlov <antonynpavlov@gmail.com>
To: barebox <barebox@lists.infradead.org>
Subject: SPI chip select problem
Date: Mon, 25 Jun 2012 11:45:06 +0400	[thread overview]
Message-ID: <CAA4bVAHvo6i3uOoEao=q8RCP+i3NZ+9XnmvA=mKjEYZztrmB2g@mail.gmail.com> (raw)

Hi!

I have added spi controller driver for one of my MIPS boards and
found, that there is a problem with chip select.

During initialisation we call *_spi_setup() method. It switch chip
select and frequency for every probing spi slave chip.
But after initialisation __we never__ call this method. So if I have
more than 1 spi slave chip, I can use only last of them.

There is the 'cs_change' flag for *_spi_transfer() method, but this
flag does not used at all!

I have made quick-and-dirty patch:

--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -196,6 +196,8 @@ EXPORT_SYMBOL(spi_register_master);

 int spi_sync(struct spi_device *spi, struct spi_message *message)
 {
+       spi->master->setup(spi);
+
        return spi->master->transfer(spi, message);
 }

-- 
Best regards,
  Antony Pavlov

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             reply	other threads:[~2012-06-25  7:45 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-25  7:45 Antony Pavlov [this message]
2012-06-25  8:53 ` Johannes Stezenbach
2012-06-25 10:07   ` Antony Pavlov
2012-06-25 10:48     ` Johannes Stezenbach

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