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<section id="sh7760-sh7763-integrated-lcdc-framebuffer-driver">
<h1>SH7760/SH7763 integrated LCDC Framebuffer driver<a class="headerlink" href="#sh7760-sh7763-integrated-lcdc-framebuffer-driver" title="Link to this heading">¶</a></h1>
<section id="overview">
<h2>0. Overview<a class="headerlink" href="#overview" title="Link to this heading">¶</a></h2>
<p>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.</p>
<p>Caveats:</p>
<ul class="simple">
<li><p>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.</p></li>
<li><p>The driver does not support changing resolution while loaded
(displays aren’t hotpluggable anyway)</p></li>
<li><p>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.</p></li>
<li><p>Rotation works only 90degress clockwise, and only if horizontal
resolution is <= 320 pixels.</p></li>
</ul>
<dl class="simple">
<dt>Files:</dt><dd><ul class="simple">
<li><p>drivers/video/sh7760fb.c</p></li>
<li><p>include/asm-sh/sh7760fb.h</p></li>
<li><p><a class="reference internal" href="#"><span class="doc">SH7760/SH7763 integrated LCDC Framebuffer driver</span></a></p></li>
</ul>
</dd>
</dl>
</section>
<section id="platform-setup">
<h2>1. Platform setup<a class="headerlink" href="#platform-setup" title="Link to this heading">¶</a></h2>
<dl>
<dt>SH7760:</dt><dd><p>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).</p>
<p>PFC registers PCCR and PCDR must be set to peripheral mode.
(write zeros to both).</p>
</dd>
</dl>
<p>The driver does NOT do the above for you since board setup is, well, job
of the board setup code.</p>
</section>
<section id="panel-definitions">
<h2>2. Panel definitions<a class="headerlink" href="#panel-definitions" title="Link to this heading">¶</a></h2>
<p>The LCDC must explicitly be told about the type of LCD panel
attached. Data must be wrapped in a “<code class="xref c c-struct broken_xref docutils literal notranslate"><span class="pre">struct</span> <span class="pre">sh7760fb_platdata</span></code>” and
passed to the driver as platform_data.</p>
<p>Suggest you take a closer look at the SH7760 Manual, Section 30.
(<a class="reference external" href="http://documentation.renesas.com/eng/products/mpumcu/e602291_sh7760.pdf">http://documentation.renesas.com/eng/products/mpumcu/e602291_sh7760.pdf</a>)</p>
<p>The following code illustrates what needs to be done to
get the framebuffer working on a 640x480 TFT:</p>
<div class="highlight-none notranslate"><div class="highlight"><pre><span></span>#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),
};
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