Re: SSD1306 OLED driver

On Fri, Jan 09, 2015 at 06:13:43PM +0530, Ssagarr Patil wrote:

Hi Maxime,

Thanks for your response!

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On Fri, Jan 09, 2015 at 03:45:01PM +0530, Ssagarr Patil wrote:

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Hi Maxime,

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Thanks for the pointer, I am using spi_write() call and I see /dev/fb0 node created.
but when I do echo "1121"> /dev/fb0 nothing comes up on oled any pointers on this ?

You can't use it like that. It's a standard framebuffer, that is
represented as an array of pixels, so you need to use a font rendering
software if you want to output some text.

can fbtest
(https://git.kernel.org/cgit/linux/kernel/git/geert/fbtest.git/)
be used to to draw something ?

how do I set pixels of it ? Please if you can point me to some stuff that would be helpful.

Last time I tried, fbtest didn't support monochrome display.

And you'll find anything you need in the documentation.
https://www.kernel.org/doc/Documentation/fb/framebuffer.txt

In my case I see that init is done but I dont see any pixels on the
screen at all.

I am now concerned if the driver was tested in first place ?

No. I just submitted some good looking code that never ever got
tested.

More seriously, There's a few thing that comes to my mind:
  - Your controller doesn't behave the same way than the ones already
    supported.
  - You haven't posted your changes yet, so maybe you're not doing the
    transfers right
  - Your SPI controller is doing something weird

What happens if you plug a logical analyzer on the bus?

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com