[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>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
index 45108ed85588..d5f24089be71 100644
--- a/drivers/mtd/devices/m25p80.c
+++ b/drivers/mtd/devices/m25p80.c
@@ -378,7 +378,9 @@ static int m25p80_write(struct mtd_info *mtd, loff_t to, size_t len,
 
                         spi_sync(flash->spi, &m);
 
-                        *retlen += m.actual_length - sizeof(flash->command);
+                        if (retlen)
+                                *retlen += m.actual_length
+                                        - sizeof(flash->command);
                 }
         }