From e49e48d5f3acc73ae6fc1137683ec3c488e7964d Mon Sep 17 00:00:00 2001
From: Jakob Kaivo <jakob@kaivo.net>
Date: Sat, 10 Nov 2018 21:30:21 -0500
Subject: work on initializing the screens

---
 fb.c | 96 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 96 insertions(+)
 create mode 100644 fb.c

(limited to 'fb.c')

diff --git a/fb.c b/fb.c
new file mode 100644
index 0000000..2b0d116
--- /dev/null
+++ b/fb.c
@@ -0,0 +1,96 @@
+#include <fcntl.h>
+#include <stdio.h>
+#include <sys/mman.h>
+#include <unistd.h>
+
+#include <linux/fb.h>
+#include <sys/ioctl.h>
+
+#include "fb.h"
+#include "gpio.h"
+
+struct imx_epdc_fb_mode {
+	struct fb_videomode *vmode;
+	int vscan_holdoff;
+	int sdoed_width;
+	int sdoed_delay;
+	int sdoez_width;
+	int sdoez_delay;
+	int gdclk_hp_offs;
+	int gdsp_offs;
+	int gdoe_offs;
+	int gdclk_offs;
+	int num_ce;
+};
+
+static char *fbaddr;
+
+void dumpsi(const char *ctl, int io, struct fb_var_screeninfo *si)
+{
+	printf("- %s\n", ctl);
+	printf("\tioctl returned %d\n", io);
+	printf("\txres: %d\n", si->xres);
+	printf("\tyres: %d\n", si->yres);
+	printf("\txres_virtual: %d\n", si->xres_virtual);
+	printf("\tyres_virtual: %d\n", si->yres_virtual);
+	printf("\txoffset: %d\n", si->xoffset);
+	printf("\tyoffset: %d\n", si->yoffset);
+	printf("\tbits_per_pixel: %d\n", si->bits_per_pixel);
+	printf("\tgrayscale: %d\n", si->grayscale);
+}
+
+void dumpfsi(const char *ctl, int io, struct fb_fix_screeninfo *fsi)
+{
+	printf("- %s\n", ctl);
+	printf("\tioctl returned %d\n", io);
+	printf("\tid: %16s\n", fsi->id);
+	printf("\tsmem_len: %d\n", fsi->smem_len);
+	printf("\ttype: %d\n", fsi->type);
+	printf("\ttype_aux: %d\n", fsi->type_aux);
+	printf("\tvisual: %d\n", fsi->visual);
+	printf("\txpanstep: %d\n", fsi->xpanstep);
+	printf("\typanstep: %d\n", fsi->ypanstep);
+	printf("\tywrapstep: %d\n", fsi->ywrapstep);
+	printf("\tline_length: %d\n", fsi->line_length);
+	printf("\tmmio_start: %lu\n", fsi->mmio_start);
+	printf("\tmmio_len: %d\n", fsi->mmio_len);
+	printf("\taccel: %d\n", fsi->accel);
+	printf("\tcapabilities: %d\n", fsi->capabilities);
+}
+
+void fb_init(void)
+{
+	printf("enabling left display\n");
+	gpio_set(ENABLE_LEFT_DISPLAY);
+	printf("enabling right display\n");
+	gpio_set(ENABLE_RIGHT_DISPLAY);
+
+
+	printf("mapping framebuffer...\n");
+	struct fb_var_screeninfo si = { 0 };
+	
+	int fbfd = open("/dev/fb0", O_RDWR);
+
+	struct fb_fix_screeninfo fsi;
+	int io = ioctl(fbfd, FBIOGET_FSCREENINFO, &fsi);
+	dumpfsi("FBIOGET_FSCREENINFO", io, &fsi);
+
+	io = ioctl(fbfd, FBIOGET_VSCREENINFO, &si);
+	dumpsi("FBIOEGET_VSCREENINFO", io, &si);
+
+	si.bits_per_pixel = 8;
+	si.grayscale = 1;
+	si.activate = FB_ACTIVATE_FORCE;
+
+	io = ioctl(fbfd, FBIOPUT_VSCREENINFO, &si); 
+	dumpsi("FBIOPUT_VSCREENINFO", io, &si);
+
+	fbaddr = mmap(NULL, fsi.smem_len, PROT_READ | PROT_WRITE, MAP_PRIVATE, fbfd, 0);
+
+	for (unsigned int i = 0; i < fsi.smem_len; i++) {
+		fbaddr[i] = i % 2 == 0 ? '\0' : '\xff';
+	}
+
+	close(fbfd);
+	printf("at %p\n", fbaddr);
+}
-- 
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