src/drivers/framebuffer/intel_i915.c

/*
 * Copyright 2016 Google Inc.
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but without any warranty; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */

#include "base/io.h"
#include "base/container_of.h"
#include "base/xalloc.h"
#include "drivers/framebuffer/intel_i915.h"

enum {
	BlcPchPwmCtl1Offset = 0xc8250,
	BlcPchPwmEnable = 1 << 31,
};

static int intel_i915_framebuffer_prepare(FrameBufferOps *me, FrameBuffer *buf)
{
	IntelI915Framebuffer *fb = container_of(me, IntelI915Framebuffer, ops);

	if (!fb->base)
		fb->base = pci_read_config32(fb->bdf, PciConfBar0) & ~0xf;

	return framebuffer_read_from_fwdb(buf);
}

static int intel_i915_framebuffer_backlight_set(GpioOps *me, unsigned enable)
{
	IntelI915Framebuffer *fb =
		container_of(me, IntelI915Framebuffer, backlight);

	uint32_t *blc = (uint32_t *)(fb->base + BlcPchPwmCtl1Offset);

	uint32_t old_val = read32(blc);
	uint32_t new_val = enable ? (old_val | BlcPchPwmEnable) :
				    (old_val & ~BlcPchPwmEnable);

	if (old_val != new_val)
		write32(blc, new_val);

	return 0;
}

IntelI915Framebuffer *new_intel_i915_framebuffer(pcidev_t bdf)
{
	IntelI915Framebuffer *fb = xzalloc(sizeof(*fb));

	fb->ops.prepare = &intel_i915_framebuffer_prepare;

	fb->backlight.set = &intel_i915_framebuffer_backlight_set;

	fb->bdf = bdf;

	return fb;
}