1================================================ 2SH7760/SH7763 integrated LCDC Framebuffer driver 3================================================ 4 50. Overview 6----------- 7The SH7760/SH7763 have an integrated LCD Display controller (LCDC) which 8supports (in theory) resolutions ranging from 1x1 to 1024x1024, 9with color depths ranging from 1 to 16 bits, on STN, DSTN and TFT Panels. 10 11Caveats: 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 28Files: 29 - drivers/video/sh7760fb.c 30 - include/asm-sh/sh7760fb.h 31 - Documentation/fb/sh7760fb.rst 32 331. Platform setup 34----------------- 35SH7760: 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 43The driver does NOT do the above for you since board setup is, well, job 44of the board setup code. 45 462. Panel definitions 47-------------------- 48The LCDC must explicitly be told about the type of LCD panel 49attached. Data must be wrapped in a "struct sh7760fb_platdata" and 50passed to the driver as platform_data. 51 52Suggest you take a closer look at the SH7760 Manual, Section 30. 53(http://documentation.renesas.com/eng/products/mpumcu/e602291_sh7760.pdf) 54 55The following code illustrates what needs to be done to 56get 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 }; 131