Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | Driver for PXA25x LCD controller |
2 | ================================ | |
3 | ||
4 | The driver supports the following options, either via | |
5 | options=<OPTIONS> when modular or video=pxafb:<OPTIONS> when built in. | |
6 | ||
7 | For example: | |
77e19675 | 8 | modprobe pxafb options=vmem:2M,mode:640x480-8,passive |
1da177e4 | 9 | or on the kernel command line |
77e19675 EM |
10 | video=pxafb:vmem:2M,mode:640x480-8,passive |
11 | ||
12 | vmem: VIDEO_MEM_SIZE | |
13 | Amount of video memory to allocate (can be suffixed with K or M | |
14 | for kilobytes or megabytes) | |
1da177e4 LT |
15 | |
16 | mode:XRESxYRES[-BPP] | |
17 | XRES == LCCR1_PPL + 1 | |
18 | YRES == LLCR2_LPP + 1 | |
19 | The resolution of the display in pixels | |
20 | BPP == The bit depth. Valid values are 1, 2, 4, 8 and 16. | |
21 | ||
22 | pixclock:PIXCLOCK | |
23 | Pixel clock in picoseconds | |
24 | ||
25 | left:LEFT == LCCR1_BLW + 1 | |
26 | right:RIGHT == LCCR1_ELW + 1 | |
27 | hsynclen:HSYNC == LCCR1_HSW + 1 | |
28 | upper:UPPER == LCCR2_BFW | |
29 | lower:LOWER == LCCR2_EFR | |
30 | vsynclen:VSYNC == LCCR2_VSW + 1 | |
31 | Display margins and sync times | |
32 | ||
33 | color | mono => LCCR0_CMS | |
34 | umm... | |
35 | ||
36 | active | passive => LCCR0_PAS | |
37 | Active (TFT) or Passive (STN) display | |
38 | ||
39 | single | dual => LCCR0_SDS | |
40 | Single or dual panel passive display | |
41 | ||
42 | 4pix | 8pix => LCCR0_DPD | |
43 | 4 or 8 pixel monochrome single panel data | |
44 | ||
45 | hsync:HSYNC | |
46 | vsync:VSYNC | |
47 | Horizontal and vertical sync. 0 => active low, 1 => active | |
48 | high. | |
49 | ||
50 | dpc:DPC | |
51 | Double pixel clock. 1=>true, 0=>false | |
52 | ||
53 | outputen:POLARITY | |
54 | Output Enable Polarity. 0 => active low, 1 => active high | |
55 | ||
56 | pixclockpol:POLARITY | |
57 | pixel clock polarity | |
58 | 0 => falling edge, 1 => rising edge | |
198fc108 EM |
59 | |
60 | ||
61 | Overlay Support for PXA27x and later LCD controllers | |
62 | ==================================================== | |
63 | ||
64 | PXA27x and later processors support overlay1 and overlay2 on-top of the | |
65 | base framebuffer (although under-neath the base is also possible). They | |
66 | support palette and no-palette RGB formats, as well as YUV formats (only | |
67 | available on overlay2). These overlays have dedicated DMA channels and | |
68 | behave in a similar way as a framebuffer. | |
69 | ||
70 | However, there are some differences between these overlay framebuffers | |
71 | and normal framebuffers, as listed below: | |
72 | ||
73 | 1. overlay can start at a 32-bit word aligned position within the base | |
74 | framebuffer, which means they have a start (x, y). This information | |
75 | is encoded into var->nonstd (no, var->xoffset and var->yoffset are | |
76 | not for such purpose). | |
77 | ||
78 | 2. overlay framebuffer is allocated dynamically according to specified | |
79 | 'struct fb_var_screeninfo', the amount is decided by: | |
80 | ||
81 | var->xres_virtual * var->yres_virtual * bpp | |
82 | ||
83 | bpp = 16 -- for RGB565 or RGBT555 | |
84 | = 24 -- for YUV444 packed | |
85 | = 24 -- for YUV444 planar | |
86 | = 16 -- for YUV422 planar (1 pixel = 1 Y + 1/2 Cb + 1/2 Cr) | |
87 | = 12 -- for YUV420 planar (1 pixel = 1 Y + 1/4 Cb + 1/4 Cr) | |
88 | ||
89 | NOTE: | |
90 | ||
91 | a. overlay does not support panning in x-direction, thus | |
92 | var->xres_virtual will always be equal to var->xres | |
93 | ||
94 | b. line length of overlay(s) must be on a 32-bit word boundary, | |
95 | for YUV planar modes, it is a requirement for the component | |
96 | with minimum bits per pixel, e.g. for YUV420, Cr component | |
97 | for one pixel is actually 2-bits, it means the line length | |
98 | should be a multiple of 16-pixels | |
99 | ||
100 | c. starting horizontal position (XPOS) should start on a 32-bit | |
101 | word boundary, otherwise the fb_check_var() will just fail. | |
102 | ||
103 | d. the rectangle of the overlay should be within the base plane, | |
104 | otherwise fail | |
105 | ||
106 | Applications should follow the sequence below to operate an overlay | |
107 | framebuffer: | |
108 | ||
109 | a. open("/dev/fb[1-2]", ...) | |
110 | b. ioctl(fd, FBIOGET_VSCREENINFO, ...) | |
111 | c. modify 'var' with desired parameters: | |
112 | 1) var->xres and var->yres | |
113 | 2) larger var->yres_virtual if more memory is required, | |
114 | usually for double-buffering | |
115 | 3) var->nonstd for starting (x, y) and color format | |
116 | 4) var->{red, green, blue, transp} if RGB mode is to be used | |
117 | d. ioctl(fd, FBIOPUT_VSCREENINFO, ...) | |
118 | e. ioctl(fd, FBIOGET_FSCREENINFO, ...) | |
119 | f. mmap | |
120 | g. ... | |
121 | ||
122 | 3. for YUV planar formats, these are actually not supported within the | |
123 | framebuffer framework, application has to take care of the offsets | |
124 | and lengths of each component within the framebuffer. | |
125 | ||
126 | 4. var->nonstd is used to pass starting (x, y) position and color format, | |
127 | the detailed bit fields are shown below: | |
128 | ||
129 | 31 23 20 10 0 | |
130 | +-----------------+---+----------+----------+ | |
131 | | ... unused ... |FOR| XPOS | YPOS | | |
132 | +-----------------+---+----------+----------+ | |
133 | ||
134 | FOR - color format, as defined by OVERLAY_FORMAT_* in pxafb.h | |
135 | 0 - RGB | |
136 | 1 - YUV444 PACKED | |
137 | 2 - YUV444 PLANAR | |
138 | 3 - YUV422 PLANAR | |
139 | 4 - YUR420 PLANAR | |
140 | ||
141 | XPOS - starting horizontal position | |
142 | YPOS - starting vertical position |