linux/Documentation/fb/sh7760fb.rst
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   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