[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>

5 files changed, 28 insertions, 2 deletions

diff --git a/Documentation/spi/spi-summary b/Documentation/spi/spi-summary
index 761debf748e9..a5ffba33a351 100644
--- a/Documentation/spi/spi-summary
+++ b/Documentation/spi/spi-summary
@@ -115,6 +115,9 @@ shows up in sysfs in several locations:
    /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 @@ driver is registered:
 
 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 @@ up the spi bus master, and will likely need spi_new_device() to provide the
 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"?
 ----------------------------------------
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);
                 }
         }
 
diff --git a/drivers/mtd/devices/mtd_dataflash.c b/drivers/mtd/devices/mtd_dataflash.c
index 99d3a0320fc9..155737e7483f 100644
--- a/drivers/mtd/devices/mtd_dataflash.c
+++ b/drivers/mtd/devices/mtd_dataflash.c
@@ -508,7 +508,7 @@ add_dataflash(struct spi_device *spi, char *name,
                         priv->partitioned = 1;
                         return add_mtd_partitions(device, parts, nr_parts);
                 }
-        } else if (pdata->nr_parts)
+        } else if (pdata && pdata->nr_parts)
                 dev_warn(&spi->dev, "ignoring %d default partitions on %s\n",
                                 pdata->nr_parts, device->name);
 
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 9b21c5d77b4a..7a75faeb0526 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -65,6 +65,16 @@ config SPI_BITBANG
           need it.  You only need to select this explicitly to support driver
           modules that aren't part of this kernel tree.
 
+config SPI_BUTTERFLY
+        tristate "Parallel port adapter for AVR Butterfly (DEVELOPMENT)"
+        depends on SPI_MASTER && PARPORT && EXPERIMENTAL
+        select SPI_BITBANG
+        help
+          This uses a custom parallel port cable to connect to an AVR
+          Butterfly <http://www.atmel.com/products/avr/butterfly>, an
+          inexpensive battery powered microcontroller evaluation board.
+          This same cable can be used to flash new firmware.
+
 #
 # Add new SPI master controllers in alphabetical order above this line
 #
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 5da6a4df4012..c2c87e845abf 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_SPI_MASTER)		+= spi.o
 
 # SPI master controller drivers (bus)
 obj-$(CONFIG_SPI_BITBANG)               += spi_bitbang.o
+obj-$(CONFIG_SPI_BUTTERFLY)             += spi_butterfly.o
 #       ... add above this line ...
 
 # SPI protocol drivers (device/link on bus)