[PATCH] spi: misc fixes

This collects some small SPI patches that seem to be missing from the MM tree:

  - spi_butterfly kbuild hooks got dropped somehow; this restores them
  - quick fix for a (theoretical?) m25p80_write() oops noted by Andrew
  - quick fix for a potential config-specific oops for mtd_dataflash()
  - minor doc tweaks

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/Documentation/spi/spi-summary b/Documentation/spi/spi-summary
index 761debf..a5ffba3 100644
--- a/Documentation/spi/spi-summary
+++ b/Documentation/spi/spi-summary
@@ -115,6 +115,9 @@
    /sys/devices/.../CTLR/spiB.C ... spi_device for on bus "B",
 	chipselect C, accessed through CTLR.
 
+   /sys/devices/.../CTLR/spiB.C/modalias ... identifies the driver
+	that should be used with this device (for hotplug/coldplug)
+
    /sys/bus/spi/devices/spiB.C ... symlink to the physical
    	spiB-C device
 
@@ -247,6 +250,12 @@
 
 Like with other static board-specific setup, you won't unregister those.
 
+The widely used "card" style computers bundle memory, cpu, and little else
+onto a card that's maybe just thirty square centimeters.  On such systems,
+your arch/.../mach-.../board-*.c file would primarily provide information
+about the devices on the mainboard into which such a card is plugged.  That
+certainly includes SPI devices hooked up through the card connectors!
+
 
 NON-STATIC CONFIGURATIONS
 
@@ -258,6 +267,10 @@
 board info based on the board that was hotplugged.  Of course, you'd later
 call at least spi_unregister_device() when that board is removed.
 
+When Linux includes support for MMC/SD/SDIO/DataFlash cards through SPI, those
+configurations will also be dynamic.  Fortunately, those devices all support
+basic device identification probes, so that support should hotplug normally.
+
 
 How do I write an "SPI Protocol Driver"?
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