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drivers/video/am335x-fb: Add support for 16bpp format 

To support 16bpp we just need to change the raster_ctrl register
accordingly. Also 32bpp mode should work as well, but was not tested.
According to the TRM the uppermost byte will be ignored when
LCD_TFT_24BPP_UNPACK is set.

The switch logic is based on the Linux kernel tilcdc driver:
drivers/gpu/drm/tilcdc/tilcdc_crtc.c: lines 407 through 419
(kernel was checked out at commit: bcc981e9ed8)

Signed-off-by: Martin Pietryka <martin.pietryka@chello.at>
Reviewed-by: Hannes Schmelzer <oe5hpm@oevsv.at>
Tested-by: Hannes Schmelzer <oe5hpm@oevsv.at>
utp
Martin Pietryka 2016-04-27 21:39:15 +02:00 committed by Anatolij Gustschin
parent e25b369c04
commit 7d045170ac
1 changed files with 19 additions and 3 deletions
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22
drivers/video/am335x-fb.c
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@ -5,7 +5,7 @@
* minimal framebuffer driver for TI's AM335x SoC to be compatible with
* Wolfgang Denk's LCD-Framework (CONFIG_LCD, common/lcd.c)
*
* - supporting only 24bit RGB/TFT raster Mode (not using palette)
* - supporting 16/24/32bit RGB/TFT raster Mode (not using palette)
* - sets up LCD controller as in 'am335x_lcdpanel' struct given
* - starts output DMA from gd->fb_base buffer
*
@ -106,6 +106,8 @@ int lcd_get_size(int *line_length)
int am335xfb_init(struct am335x_lcdpanel *panel)
{
u32 raster_ctrl = 0;
if (0 == gd->fb_base) {
printf("ERROR: no valid fb_base stored in GLOBAL_DATA_PTR!\n");
return -1;
@ -115,6 +117,21 @@ int am335xfb_init(struct am335x_lcdpanel *panel)
return -1;
}
/* We can already set the bits for the raster_ctrl in this check */
switch (panel->bpp) {
case 16:
break;
case 32:
raster_ctrl |= LCD_TFT_24BPP_UNPACK;
/* fallthrough */
case 24:
raster_ctrl |= LCD_TFT_24BPP_MODE;
break;
default:
error("am335x-fb: invalid bpp value: %d\n", panel->bpp);
return -1;
}
debug("setting up LCD-Controller for %dx%dx%d (hfp=%d,hbp=%d,hsw=%d / ",
panel->hactive, panel->vactive, panel->bpp,
panel->hfp, panel->hbp, panel->hsw);
@ -157,8 +174,7 @@ int am335xfb_init(struct am335x_lcdpanel *panel)
LCD_HBPMSB(panel->hbp) |
LCD_HFPMSB(panel->hfp) |
0x0000FF00; /* clk cycles for ac-bias */
lcdhw->raster_ctrl = LCD_TFT_24BPP_MODE |
LCD_TFT_24BPP_UNPACK |
lcdhw->raster_ctrl = raster_ctrl |
LCD_PALMODE_RAWDATA |
LCD_TFT_MODE |
LCD_RASTER_ENABLE;