On Sun, Jan 19, 2014 at 03:39:34PM +0530, Jagan Teki wrote:
> > Just think about that how do you code your driver for SPI NOR _without_ this
> > framework:
> > do your driver need to call the m25p80.c? if you do call the m25p80.c, you
> > actually write your so-called "two drivers" :)
>
> I'm still not convinced here, sorry!
> Let me explain more with example, Just take your (q)spi controller as an example
> B_FSL1 designed with - serial flash
> B_FSL2 designed with - touch screen
>
> With this design If we follow current we just need one controller
> driver (drivers/spi/spi-fsl.c)
> to serve touch screen and serial flash from upper layers.
>
> MTD core Input core
> ------------- -------------------------------
> m25p80.c spi touchscreen driver (drivers/input/touchscreen)
> ----------------------------------------------------
> SPI core
> ----------------------------------------------------
> controller driver (drivers/spi/spi-fsl.)
> ----------------------------------------------------
>
> But with your new SPI-NOR
>
> MTD core
> ------------
> SPI-NOR Input core
> ----------- ------------------
> fsl-quadspi.c spi touchscreen driver (drivers/input/touchscreen)
> ---------------- ------------------------------
> SPI Core
> -----------------------------
> controller driver (drivers/spi/spi-fsl.c)
> -----------------------------------------
>
There is no relationship with the fsl-quadspi.c.
It should be like this:
MTD core
------------
SPI-NOR framework Input core
----------- ------------------
m25p80.c spi touchscreen driver (drivers/input/touchscreen)
---------------- ------------------------------
SPI Core SPI Core
----------------------- -----------------------------
drivers/spi/spi-fsl.c controller driver (drivers/spi/spi-fsl.c)
-------------------------- -----------------------------------------
> Here see we have two separate drivers for the same controller as it offers two
> functionalities. and also it never talk to Linux SPI subsystem which is not a
> good for me as intern hw is SPI-based it must talk to subsystem to make use of
> Linux SPI API's.
>
> And also you mentioned SPI-NOR controller is not a SPI controller what does that
> means because it's a NOR flash which is of SPI protocol based.
The SPI controller (or spi bus controller) only handles the _byte_ streams;
while the spi-nor controller, such as fsl-quadspi.c, can has to __known__
the exact SPI NOR command to find the proper LUT.
Please read the thread i ever posted in the previous email.
>
> I understand that your framework doing good things in matured manner, but
> seems like it's confuse to me to follow common standards - Just my
> opinion, may be I'm incorrect.
>
> One more thing question - I have 1-wire spi controller which I was
> used for flash in
> one board and keyboard in another board, so if I follow your framework
> I need to write
> a driver in drivers/mtd/spi-nor/foo-spi.c and one more in
> drivers/spi/spi-foo.c - correct?
Please read the device tree node of your controller, find the code like
...................................................
flash: m25p80@0 {
#address-cells = <1>;
#size-cells = <1>;
compatible = "st,m25p32";
spi-max-frequency = <20000000>;
reg = <0>;
};
...................................................
if you call the m25p80, you do not need to change anything.
thanks
Huang Shijie
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