[U-Boot] [PATCH] video: Add support for TI's AM335x LCD-Controller

[Hannes Petermaier]

Hi Heiko,

Heiko Schocher wrote:
> Hello Hannes,
>
> Am 06.03.2014 15:24, schrieb Hannes Petermaier:
>> On 2014-03-06 14:58, Heiko Schocher wrote:
>>> Hello Hannes,
>>>
>>> Am 06.03.2014 14:39, schrieb Hannes Petermaier:
>>>> - Adds support for a minimal framebuffer driver of TI's AM335x SoC
>>>> to be compatible with Wolfgang Denk's LCD-Framework (CONFIG_LCD,
>>>> common/lcd.c)
>>>>
>>>> Signed-off-by: Hannes Petermaier<oe5hpm at oevsv.at>
>>>> ---
>>>> drivers/video/Makefile | 1 +
>>>> drivers/video/am335x-fb.c | 169
>>>> +++++++++++++++++++++++++++++++++++++++++++++
>>>> drivers/video/am335x-fb.h | 67 ++++++++++++++++++
>>>> 3 files changed, 237 insertions(+)
>>>> create mode 100644 drivers/video/am335x-fb.c
>>>> create mode 100644 drivers/video/am335x-fb.h
>>>
>>> Why you cannot use:
>>>
>>> u-boot:drivers/video/da8xx-fb.c ?
>>>
>>> bye,
>>> Heiko
>> Hi Heiko,
>>
>> for my opinion this clone of the linux-driver is very overloaded and
>> difficult to use/configure.
>> With the words 'small-is-beautiful' and 'keep-it-simple' i've wrote a
>> few lines which do the minimum:
>> - configure raster-controller
>> - setup DMA
>> - powerON Display
>>
>> maybe we can use the small-version in other projects too.
>
> Why is it difficult to use/configure the existing driver?
>
> Look for example into the board/siemens/pxm2/board.c board, which uses
> this driver. You have to define:
>
> static struct da8xx_panel lcd_panels[]
> static const struct display_panel disp_panel
> static const struct lcd_ctrl_config lcd_cfg
>
> and call "da8xx_video_init(&lcd_panels[0], &lcd_cfg, lcd_cfg.bpp);"
>
> Thats all ...

i've looked around again for using the da8xx-fb driver and found another
detail which motivated me for writing a new instance.

--
	par->vram_virt = malloc(par->vram_size);

	par->vram_phys = (dma_addr_t) par->vram_virt;
	debug("Requesting 0x%x bytes for framebuffer at 0x%x\n",
		(unsigned int)par->vram_size,
		(unsigned int)par->vram_virt);
	if (!par->vram_virt) {
		printf("GLCD: malloc for frame buffer failed\n");
		goto err_release_fb;
	}
	gd->fb_base = (int)par->vram_virt;
--

da8xx-fb.c does allocate a new framebuffer by itself.
But in my case lcd-framework allready has reserved memory (on top of ram)
for framebuffer usage and i want use this memory from lcd-framework for
two reasons:
- don't waste memory
- have this memory really on top of ram to give the following OS (in my
case vxWorks) a pointer where it have to write Video-data.

maybe there are other possibilites to achieve this.
any ideas ?

> bye,
> Heiko

many thanks and best regards,
Hannes