| ================================================ |
| SH7760/SH7763 integrated LCDC Framebuffer driver |
| ================================================ |
| |
| 0. Overview |
| ----------- |
| The SH7760/SH7763 have an integrated LCD Display controller (LCDC) which |
| supports (in theory) resolutions ranging from 1x1 to 1024x1024, |
| with color depths ranging from 1 to 16 bits, on STN, DSTN and TFT Panels. |
| |
| Caveats: |
| |
| * Framebuffer memory must be a large chunk allocated at the top |
| of Area3 (HW requirement). Because of this requirement you should NOT |
| make the driver a module since at runtime it may become impossible to |
| get a large enough contiguous chunk of memory. |
| |
| * The driver does not support changing resolution while loaded |
| (displays aren't hotpluggable anyway) |
| |
| * Heavy flickering may be observed |
| a) if you're using 15/16bit color modes at >= 640x480 px resolutions, |
| b) during PCMCIA (or any other slow bus) activity. |
| |
| * Rotation works only 90degress clockwise, and only if horizontal |
| resolution is <= 320 pixels. |
| |
| Files: |
| - drivers/video/sh7760fb.c |
| - include/asm-sh/sh7760fb.h |
| - Documentation/fb/sh7760fb.rst |
| |
| 1. Platform setup |
| ----------------- |
| SH7760: |
| Video data is fetched via the DMABRG DMA engine, so you have to |
| configure the SH DMAC for DMABRG mode (write 0x94808080 to the |
| DMARSRA register somewhere at boot). |
| |
| PFC registers PCCR and PCDR must be set to peripheral mode. |
| (write zeros to both). |
| |
| The driver does NOT do the above for you since board setup is, well, job |
| of the board setup code. |
| |
| 2. Panel definitions |
| -------------------- |
| The LCDC must explicitly be told about the type of LCD panel |
| attached. Data must be wrapped in a "struct sh7760fb_platdata" and |
| passed to the driver as platform_data. |
| |
| Suggest you take a closer look at the SH7760 Manual, Section 30. |
| (http://documentation.renesas.com/eng/products/mpumcu/e602291_sh7760.pdf) |
| |
| The following code illustrates what needs to be done to |
| get the framebuffer working on a 640x480 TFT:: |
| |
| #include <linux/fb.h> |
| #include <asm/sh7760fb.h> |
| |
| /* |
| * NEC NL6440bc26-01 640x480 TFT |
| * dotclock 25175 kHz |
| * Xres 640 Yres 480 |
| * Htotal 800 Vtotal 525 |
| * HsynStart 656 VsynStart 490 |
| * HsynLenn 30 VsynLenn 2 |
| * |
| * The linux framebuffer layer does not use the syncstart/synclen |
| * values but right/left/upper/lower margin values. The comments |
| * for the x_margin explain how to calculate those from given |
| * panel sync timings. |
| */ |
| static struct fb_videomode nl6448bc26 = { |
| .name = "NL6448BC26", |
| .refresh = 60, |
| .xres = 640, |
| .yres = 480, |
| .pixclock = 39683, /* in picoseconds! */ |
| .hsync_len = 30, |
| .vsync_len = 2, |
| .left_margin = 114, /* HTOT - (HSYNSLEN + HSYNSTART) */ |
| .right_margin = 16, /* HSYNSTART - XRES */ |
| .upper_margin = 33, /* VTOT - (VSYNLEN + VSYNSTART) */ |
| .lower_margin = 10, /* VSYNSTART - YRES */ |
| .sync = FB_SYNC_HOR_HIGH_ACT | FB_SYNC_VERT_HIGH_ACT, |
| .vmode = FB_VMODE_NONINTERLACED, |
| .flag = 0, |
| }; |
| |
| static struct sh7760fb_platdata sh7760fb_nl6448 = { |
| .def_mode = &nl6448bc26, |
| .ldmtr = LDMTR_TFT_COLOR_16, /* 16bit TFT panel */ |
| .lddfr = LDDFR_8BPP, /* we want 8bit output */ |
| .ldpmmr = 0x0070, |
| .ldpspr = 0x0500, |
| .ldaclnr = 0, |
| .ldickr = LDICKR_CLKSRC(LCDC_CLKSRC_EXTERNAL) | |
| LDICKR_CLKDIV(1), |
| .rotate = 0, |
| .novsync = 1, |
| .blank = NULL, |
| }; |
| |
| /* SH7760: |
| * 0xFE300800: 256 * 4byte xRGB palette ram |
| * 0xFE300C00: 42 bytes ctrl registers |
| */ |
| static struct resource sh7760_lcdc_res[] = { |
| [0] = { |
| .start = 0xFE300800, |
| .end = 0xFE300CFF, |
| .flags = IORESOURCE_MEM, |
| }, |
| [1] = { |
| .start = 65, |
| .end = 65, |
| .flags = IORESOURCE_IRQ, |
| }, |
| }; |
| |
| static struct platform_device sh7760_lcdc_dev = { |
| .dev = { |
| .platform_data = &sh7760fb_nl6448, |
| }, |
| .name = "sh7760-lcdc", |
| .id = -1, |
| .resource = sh7760_lcdc_res, |
| .num_resources = ARRAY_SIZE(sh7760_lcdc_res), |
| }; |