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/*
* Copyright © 2011 Intel Corporation
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*
* Authors:
* Chris Wilson <chris@chris-wilson.co.uk>
*
*/
#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "intel_io.h"
#include "intel_chipset.h"
#include "intel_reg.h"
/* XXX PCH only today */
static uint32_t reg_read(uint32_t reg)
{
return *(volatile uint32_t *)((volatile char*)mmio + reg);
}
static void reg_write(uint32_t reg, uint32_t val)
{
*(volatile uint32_t *)((volatile char*)mmio + reg) = val;
}
int main(int argc, char** argv)
{
uint32_t current, max;
intel_get_mmio(intel_get_pci_device());
current = reg_read(BLC_PWM_CPU_CTL) & BACKLIGHT_DUTY_CYCLE_MASK;
max = reg_read(BLC_PWM_PCH_CTL2) >> 16;
printf ("current backlight value: %d%%\n", current * 100 / max);
if (argc > 1) {
uint32_t v = atoi (argv[1]) * max / 100;
if (v > max)
v = max;
reg_write(BLC_PWM_CPU_CTL,
(reg_read(BLC_PWM_CPU_CTL) &~ BACKLIGHT_DUTY_CYCLE_MASK) | v);
(void) reg_read(BLC_PWM_CPU_CTL);
printf ("set backlight to %d%%\n", v * 100 / max);
}
return 0;
}
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