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ab42b818 MCC |
1 | ================================================ |
2 | SH7760/SH7763 integrated LCDC Framebuffer driver | |
3 | ================================================ | |
4 | ||
5 | 0. Overview | |
6 | ----------- | |
7 | The SH7760/SH7763 have an integrated LCD Display controller (LCDC) which | |
8 | supports (in theory) resolutions ranging from 1x1 to 1024x1024, | |
9 | with color depths ranging from 1 to 16 bits, on STN, DSTN and TFT Panels. | |
10 | ||
11 | Caveats: | |
12 | ||
13 | * Framebuffer memory must be a large chunk allocated at the top | |
14 | of Area3 (HW requirement). Because of this requirement you should NOT | |
15 | make the driver a module since at runtime it may become impossible to | |
16 | get a large enough contiguous chunk of memory. | |
17 | ||
18 | * The driver does not support changing resolution while loaded | |
19 | (displays aren't hotpluggable anyway) | |
20 | ||
21 | * Heavy flickering may be observed | |
22 | a) if you're using 15/16bit color modes at >= 640x480 px resolutions, | |
23 | b) during PCMCIA (or any other slow bus) activity. | |
24 | ||
25 | * Rotation works only 90degress clockwise, and only if horizontal | |
26 | resolution is <= 320 pixels. | |
27 | ||
28 | Files: | |
29 | - drivers/video/sh7760fb.c | |
30 | - include/asm-sh/sh7760fb.h | |
31 | - Documentation/fb/sh7760fb.rst | |
32 | ||
33 | 1. Platform setup | |
34 | ----------------- | |
35 | SH7760: | |
36 | Video data is fetched via the DMABRG DMA engine, so you have to | |
37 | configure the SH DMAC for DMABRG mode (write 0x94808080 to the | |
38 | DMARSRA register somewhere at boot). | |
39 | ||
40 | PFC registers PCCR and PCDR must be set to peripheral mode. | |
41 | (write zeros to both). | |
42 | ||
43 | The driver does NOT do the above for you since board setup is, well, job | |
44 | of the board setup code. | |
45 | ||
46 | 2. Panel definitions | |
47 | -------------------- | |
48 | The LCDC must explicitly be told about the type of LCD panel | |
49 | attached. Data must be wrapped in a "struct sh7760fb_platdata" and | |
50 | passed to the driver as platform_data. | |
51 | ||
52 | Suggest you take a closer look at the SH7760 Manual, Section 30. | |
53 | (http://documentation.renesas.com/eng/products/mpumcu/e602291_sh7760.pdf) | |
54 | ||
55 | The following code illustrates what needs to be done to | |
56 | get the framebuffer working on a 640x480 TFT:: | |
57 | ||
58 | #include <linux/fb.h> | |
59 | #include <asm/sh7760fb.h> | |
60 | ||
61 | /* | |
62 | * NEC NL6440bc26-01 640x480 TFT | |
63 | * dotclock 25175 kHz | |
64 | * Xres 640 Yres 480 | |
65 | * Htotal 800 Vtotal 525 | |
66 | * HsynStart 656 VsynStart 490 | |
67 | * HsynLenn 30 VsynLenn 2 | |
68 | * | |
69 | * The linux framebuffer layer does not use the syncstart/synclen | |
70 | * values but right/left/upper/lower margin values. The comments | |
71 | * for the x_margin explain how to calculate those from given | |
72 | * panel sync timings. | |
73 | */ | |
74 | static struct fb_videomode nl6448bc26 = { | |
75 | .name = "NL6448BC26", | |
76 | .refresh = 60, | |
77 | .xres = 640, | |
78 | .yres = 480, | |
79 | .pixclock = 39683, /* in picoseconds! */ | |
80 | .hsync_len = 30, | |
81 | .vsync_len = 2, | |
82 | .left_margin = 114, /* HTOT - (HSYNSLEN + HSYNSTART) */ | |
83 | .right_margin = 16, /* HSYNSTART - XRES */ | |
84 | .upper_margin = 33, /* VTOT - (VSYNLEN + VSYNSTART) */ | |
85 | .lower_margin = 10, /* VSYNSTART - YRES */ | |
86 | .sync = FB_SYNC_HOR_HIGH_ACT | FB_SYNC_VERT_HIGH_ACT, | |
87 | .vmode = FB_VMODE_NONINTERLACED, | |
88 | .flag = 0, | |
89 | }; | |
90 | ||
91 | static struct sh7760fb_platdata sh7760fb_nl6448 = { | |
92 | .def_mode = &nl6448bc26, | |
93 | .ldmtr = LDMTR_TFT_COLOR_16, /* 16bit TFT panel */ | |
94 | .lddfr = LDDFR_8BPP, /* we want 8bit output */ | |
95 | .ldpmmr = 0x0070, | |
96 | .ldpspr = 0x0500, | |
97 | .ldaclnr = 0, | |
98 | .ldickr = LDICKR_CLKSRC(LCDC_CLKSRC_EXTERNAL) | | |
99 | LDICKR_CLKDIV(1), | |
100 | .rotate = 0, | |
101 | .novsync = 1, | |
102 | .blank = NULL, | |
103 | }; | |
104 | ||
105 | /* SH7760: | |
106 | * 0xFE300800: 256 * 4byte xRGB palette ram | |
107 | * 0xFE300C00: 42 bytes ctrl registers | |
108 | */ | |
109 | static struct resource sh7760_lcdc_res[] = { | |
110 | [0] = { | |
111 | .start = 0xFE300800, | |
112 | .end = 0xFE300CFF, | |
113 | .flags = IORESOURCE_MEM, | |
114 | }, | |
115 | [1] = { | |
116 | .start = 65, | |
117 | .end = 65, | |
118 | .flags = IORESOURCE_IRQ, | |
119 | }, | |
120 | }; | |
121 | ||
122 | static struct platform_device sh7760_lcdc_dev = { | |
123 | .dev = { | |
124 | .platform_data = &sh7760fb_nl6448, | |
125 | }, | |
126 | .name = "sh7760-lcdc", | |
127 | .id = -1, | |
128 | .resource = sh7760_lcdc_res, | |
129 | .num_resources = ARRAY_SIZE(sh7760_lcdc_res), | |
130 | }; |