1 /*
2 * Copyright © 2011 Intel Corporation
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
21 * DEALINGS IN THE SOFTWARE.
22 *
23 * Authors:
24 * Chris Wilson <chris@chris-wilson.co.uk>
25 *
26 */
27
28 #include <stdint.h>
29 #include <stdlib.h>
30 #include <stdio.h>
31 #include <string.h>
32
33 #include "intel_io.h"
34 #include "intel_chipset.h"
35 #include "intel_reg.h"
36
37 /* XXX PCH only today */
38
main(int argc,char ** argv)39 int main(int argc, char** argv)
40 {
41 uint32_t current, max;
42
43 intel_mmio_use_pci_bar(intel_get_pci_device());
44
45 current = INREG(BLC_PWM_CPU_CTL) & BACKLIGHT_DUTY_CYCLE_MASK;
46 max = INREG(BLC_PWM_PCH_CTL2) >> 16;
47
48 printf ("current backlight value: %d%%\n", current * 100 / max);
49
50 if (argc > 1) {
51 uint32_t v = atoi (argv[1]) * max / 100;
52 if (v > max)
53 v = max;
54 OUTREG(BLC_PWM_CPU_CTL,
55 (INREG(BLC_PWM_CPU_CTL) &~ BACKLIGHT_DUTY_CYCLE_MASK) | v);
56 (void) INREG(BLC_PWM_CPU_CTL);
57 printf ("set backlight to %d%%\n", v * 100 / max);
58 }
59
60 return 0;
61 }
62