This patch adds the document for the SPI NOR framework.
Signed-off-by: Huang Shijie <b32955@xxxxxxxxxxxxx>
---
fix a typo
---
Documentation/mtd/spi-nor.txt | 59 +++++++++++++++++++++++++++++++++++++++++
1 files changed, 59 insertions(+), 0 deletions(-)
create mode 100644 Documentation/mtd/spi-nor.txt
diff --git a/Documentation/mtd/spi-nor.txt b/Documentation/mtd/spi-nor.txt
new file mode 100644
index 0000000..294d5b0
--- /dev/null
+++ b/Documentation/mtd/spi-nor.txt
@@ -0,0 +1,59 @@
+ SPI NOR framework
+ ============================================
+
+Part I - why we need this framework?
+-------------------------------------
+
+The SPI bus controller only deals with the byte stream.
+Some controller does not works like a SPI bus controller, it works
+like a SPI NOR controller instead, such as the Freescale's QuadSPI controller.
+
+The Freescale's QuadSPI controller should know the NOR commands to
+find the right LUT sequence. Unfortunately, the old code can not meet
+this requirement.
+
+Part II - How does the framework work?
+-------------------------------------
+
+This framework just adds a new layer between the MTD and the SPI bus driver.
+With this new layer, the SPI NOR controller driver does not depend on the
+m25p80 code anymore.
+
+ Before this framework, the layer is like:
+
+ MTD
+ ------------------------
+ m25p80
+ ------------------------
+ SPI bus driver
+ ------------------------
+ SPI NOR chip
+
+ After this framework, the layer is like:
+ MTD
+ ------------------------
+ SPI NOR framework
+ ------------------------
+ m25p80
+ ------------------------
+ SPI bus driver
+ ------------------------
+ SPI NOR chip
+
+ With the SPI NOR controller driver(Freescale QuadSPI), it looks like:
+ MTD
+ ------------------------
+ SPI NOR framework
+ ------------------------
+ fsl-quadSPI
+ ------------------------
+ SPI NOR chip
+
+Part III - How can the drivers use the framework
+-------------------------------------
+
+The main API is the spi_nor_scan(). Before you call the hook, you should
+initialize the necessary fields for spi_nor{}.
+Please see the drivers/mtd/spi-nor/spi-nor.c for detail.
+Please also reference to the fsl-quadspi.c when you want to write a new driver
+for a SPI NOR controller.
--
1.7.2.rc3
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
