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