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authorJamie Iles <jamie@jamieiles.com>2011-12-18 10:00:49 +0000
committerDavid Woodhouse <David.Woodhouse@intel.com>2012-01-09 18:23:58 +0000
commit775c32208708de3e2e2379c85e429ab11957f864 (patch)
tree1b40ad4ce02cdea3ae988c9ce8fe4e14986ec875 /Documentation/devicetree
parentf98872fc14ecb96f796443911b6bc4767e58e885 (diff)
downloadlwn-775c32208708de3e2e2379c85e429ab11957f864.tar.gz
lwn-775c32208708de3e2e2379c85e429ab11957f864.zip
mtd: gpio-nand: add device tree bindings
Add device tree bindings so that the gpio-nand driver may be instantiated from the device tree. This also allows the partitions to be specified in the device tree. v7: - restore runtime device tree/non device tree detection v6: - convert to mtd_device_parse_register() v5: - fold dt config helpers into a single gpio_nand_of_get_config() v4: - get io sync address from gpio-control-nand,io-sync-reg property rather than a resource - clarified a few details in the binding v3: - remove redundant cast and a couple of whitespace/naming changes v2: - add CONFIG_OF guards for non-dt platforms - compatible becomes gpio-control-nand - clarify some binding details Signed-off-by: Jamie Iles <jamie@jamieiles.com> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@linux.intel.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Diffstat (limited to 'Documentation/devicetree')
-rw-r--r--Documentation/devicetree/bindings/mtd/gpio-control-nand.txt44
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diff --git a/Documentation/devicetree/bindings/mtd/gpio-control-nand.txt b/Documentation/devicetree/bindings/mtd/gpio-control-nand.txt
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+GPIO assisted NAND flash
+
+The GPIO assisted NAND flash uses a memory mapped interface to
+read/write the NAND commands and data and GPIO pins for the control
+signals.
+
+Required properties:
+- compatible : "gpio-control-nand"
+- reg : should specify localbus chip select and size used for the chip. The
+ resource describes the data bus connected to the NAND flash and all accesses
+ are made in native endianness.
+- #address-cells, #size-cells : Must be present if the device has sub-nodes
+ representing partitions.
+- gpios : specifies the gpio pins to control the NAND device. nwp is an
+ optional gpio and may be set to 0 if not present.
+
+Optional properties:
+- bank-width : Width (in bytes) of the device. If not present, the width
+ defaults to 1 byte.
+- chip-delay : chip dependent delay for transferring data from array to
+ read registers (tR). If not present then a default of 20us is used.
+- gpio-control-nand,io-sync-reg : A 64-bit physical address for a read
+ location used to guard against bus reordering with regards to accesses to
+ the GPIO's and the NAND flash data bus. If present, then after changing
+ GPIO state and before and after command byte writes, this register will be
+ read to ensure that the GPIO accesses have completed.
+
+Examples:
+
+gpio-nand@1,0 {
+ compatible = "gpio-control-nand";
+ reg = <1 0x0000 0x2>;
+ #address-cells = <1>;
+ #size-cells = <1>;
+ gpios = <&banka 1 0 /* rdy */
+ &banka 2 0 /* nce */
+ &banka 3 0 /* ale */
+ &banka 4 0 /* cle */
+ 0 /* nwp */>;
+
+ partition@0 {
+ ...
+ };
+};