Linux Driver development for OMAP35x

Annie Zhang

Hi,

I am new to driver development for Linux, so I may ask some very basic question. My display LCD power up sequence requires to using SPI to setup the register of the LCD controller. My question is how can I be sure that the SPI driver is ready when I do my DSS driver load if I build the driver statically to the kernel? Or in my case, the loadable module is a best choice? I am using OMAP35x EVM and Linux platform and plan to modify current dss.c, and I already have a sets of function (in the uboot environment) to drive our new LCD display. Thanks.

Annie

over 14 years ago

0 Vaibhav Hiremath over 14 years ago

TI__Expert 8180 points

Hi Annie,

I would suggest you to refer to the

http://arago-project.org/git/people/vaibhav/ti-psp-omap-video.git?p=people/vaibhav/ti-psp-omap-video.git;a=blob;f=drivers/video/omap2/displays/panel-acx565akm.c;h=1f8eb70e2937bbcb101d14ffe9b7238bad79b570;hb=omap3cam-mc-devel

This display panel uses SPI interface, I would suggest you to have seperate file like this for your panel. Also please try to follow the framework that would be helpful for you if you decide to push your code to upstream.

Thanks,

Vaibhav

0 Annie Zhang over 14 years ago in reply to Vaibhav Hiremath

Intellectual 460 points

Hi, Vaibhav,

Thanks. My new display has different dimensions from SHARP, I run an application previous run fine with SHARP LCD, now it returned error opening frame buffer device, /dev/fb0. Is that because of that? how do I figure out the /dev/fb0 setting?

Thanks.

0 Vaibhav Hiremath over 14 years ago in reply to Annie Zhang

TI__Expert 8180 points

Hi Zhang,

This means Frame-buffer initialization is failed, and this could be due to various reasons, boot-log should be able to give you further information about the failure. As far as Fbdev settings/status is concerned you can use one of following options -

- fbset command

- FBIO_GETVSCREENINFO ioctl

- Finally /sys/class/graphics/fb0/ sysfs interface.

Thanks,

Vaibhav

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Linux Driver development for OMAP35x