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 };
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