Documentation: add MTD sysfs docs

Signed-off-by: Kevin Cernekee <kpc.mtd@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

diff --git a/Documentation/ABI/testing/sysfs-class-mtd b/Documentation/ABI/testing/sysfs-class-mtd
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+What:          /sys/class/mtd/
+Date:          April 2009
+KernelVersion: 2.6.29
+Contact:       linux-mtd@lists.infradead.org
+Description:
+               The mtd/ class subdirectory belongs to the MTD subsystem
+               (MTD core).
+
+What:          /sys/class/mtd/mtdX/
+Date:          April 2009
+KernelVersion: 2.6.29
+Contact:       linux-mtd@lists.infradead.org
+Description:
+               The /sys/class/mtd/mtd{0,1,2,3,...} directories correspond
+               to each /dev/mtdX character device.  These may represent
+               physical/simulated flash devices, partitions on a flash
+               device, or concatenated flash devices.  They exist regardless
+               of whether CONFIG_MTD_CHAR is actually enabled.
+
+What:          /sys/class/mtd/mtdXro/
+Date:          April 2009
+KernelVersion: 2.6.29
+Contact:       linux-mtd@lists.infradead.org
+Description:
+               These directories provide the corresponding read-only device
+               nodes for /sys/class/mtd/mtdX/ .  They are only created
+               (for the benefit of udev) if CONFIG_MTD_CHAR is enabled.
+
+What:          /sys/class/mtd/mtdX/dev
+Date:          April 2009
+KernelVersion: 2.6.29
+Contact:       linux-mtd@lists.infradead.org
+Description:
+               Major and minor numbers of the character device corresponding
+               to this MTD device (in <major>:<minor> format).  This is the
+               read-write device so <minor> will be even.
+
+What:          /sys/class/mtd/mtdXro/dev
+Date:          April 2009
+KernelVersion: 2.6.29
+Contact:       linux-mtd@lists.infradead.org
+Description:
+               Major and minor numbers of the character device corresponding
+               to the read-only variant of thie MTD device (in
+               <major>:<minor> format).  In this case <minor> will be odd.
+
+What:          /sys/class/mtd/mtdX/erasesize
+Date:          April 2009
+KernelVersion: 2.6.29
+Contact:       linux-mtd@lists.infradead.org
+Description:
+               "Major" erase size for the device.  If numeraseregions is
+               zero, this is the eraseblock size for the entire device.
+               Otherwise, the MEMGETREGIONCOUNT/MEMGETREGIONINFO ioctls
+               can be used to determine the actual eraseblock layout.
+
+What:          /sys/class/mtd/mtdX/flags
+Date:          April 2009
+KernelVersion: 2.6.29
+Contact:       linux-mtd@lists.infradead.org
+Description:
+               A hexadecimal value representing the device flags, ORed
+               together:
+
+               0x0400: MTD_WRITEABLE - device is writable
+               0x0800: MTD_BIT_WRITEABLE - single bits can be flipped
+               0x1000: MTD_NO_ERASE - no erase necessary
+               0x2000: MTD_POWERUP_LOCK - always locked after reset
+
+What:          /sys/class/mtd/mtdX/name
+Date:          April 2009
+KernelVersion: 2.6.29
+Contact:       linux-mtd@lists.infradead.org
+Description:
+               A human-readable ASCII name for the device or partition.
+               This will match the name in /proc/mtd .
+
+What:          /sys/class/mtd/mtdX/numeraseregions
+Date:          April 2009
+KernelVersion: 2.6.29
+Contact:       linux-mtd@lists.infradead.org
+Description:
+               For devices that have variable eraseblock sizes, this
+               provides the total number of erase regions.  Otherwise,
+               it will read back as zero.
+
+What:          /sys/class/mtd/mtdX/oobsize
+Date:          April 2009
+KernelVersion: 2.6.29
+Contact:       linux-mtd@lists.infradead.org
+Description:
+               Number of OOB bytes per page.
+
+What:          /sys/class/mtd/mtdX/size
+Date:          April 2009
+KernelVersion: 2.6.29
+Contact:       linux-mtd@lists.infradead.org
+Description:
+               Total size of the device/partition, in bytes.
+
+What:          /sys/class/mtd/mtdX/type
+Date:          April 2009
+KernelVersion: 2.6.29
+Contact:       linux-mtd@lists.infradead.org
+Description:
+               One of the following ASCII strings, representing the device
+               type:
+
+               absent, ram, rom, nor, nand, dataflash, ubi, unknown
+
+What:          /sys/class/mtd/mtdX/writesize
+Date:          April 2009
+KernelVersion: 2.6.29
+Contact:       linux-mtd@lists.infradead.org
+Description:
+               Minimal writable flash unit size.  This will always be
+               a positive integer.
+
+               In the case of NOR flash it is 1 (even though individual
+               bits can be cleared).
+
+               In the case of NAND flash it is one NAND page (or a
+               half page, or a quarter page).
+
+               In the case of ECC NOR, it is the ECC block size.