1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Backlight code for via-pmu
4 *
5 * Copyright (C) 1998 Paul Mackerras and Fabio Riccardi.
6 * Copyright (C) 2001-2002 Benjamin Herrenschmidt
7 * Copyright (C) 2006      Michael Hanselmann <linux-kernel@hansmi.ch>
8 *
9 */
10
11#include <asm/ptrace.h>
12#include <linux/adb.h>
13#include <linux/backlight.h>
14#include <linux/pmu.h>
15#include <asm/backlight.h>
16
17#define MAX_PMU_LEVEL 0xFF
18
19static const struct backlight_ops pmu_backlight_data;
20static DEFINE_SPINLOCK(pmu_backlight_lock);
21static int sleeping, uses_pmu_bl;
22static u8 bl_curve[FB_BACKLIGHT_LEVELS];
23
24static void pmu_backlight_init_curve(u8 off, u8 min, u8 max)
25{
26	int i, flat, count, range = (max - min);
27
28	bl_curve[0] = off;
29
30	for (flat = 1; flat < (FB_BACKLIGHT_LEVELS / 16); ++flat)
31		bl_curve[flat] = min;
32
33	count = FB_BACKLIGHT_LEVELS * 15 / 16;
34	for (i = 0; i < count; ++i)
35		bl_curve[flat + i] = min + (range * (i + 1) / count);
36}
37
38static int pmu_backlight_curve_lookup(int value)
39{
40	int level = (FB_BACKLIGHT_LEVELS - 1);
41	int i, max = 0;
42
43	/* Look for biggest value */
44	for (i = 0; i < FB_BACKLIGHT_LEVELS; i++)
45		max = max((int)bl_curve[i], max);
46
47	/* Look for nearest value */
48	for (i = 0; i < FB_BACKLIGHT_LEVELS; i++) {
49		int diff = abs(bl_curve[i] - value);
50		if (diff < max) {
51			max = diff;
52			level = i;
53		}
54	}
55	return level;
56}
57
58static int pmu_backlight_get_level_brightness(int level)
59{
60	int pmulevel;
61
62	/* Get and convert the value */
63	pmulevel = bl_curve[level] * FB_BACKLIGHT_MAX / MAX_PMU_LEVEL;
64	if (pmulevel < 0)
65		pmulevel = 0;
66	else if (pmulevel > MAX_PMU_LEVEL)
67		pmulevel = MAX_PMU_LEVEL;
68
69	return pmulevel;
70}
71
72static int __pmu_backlight_update_status(struct backlight_device *bd)
73{
74	struct adb_request req;
75	int level = backlight_get_brightness(bd);
76
77	if (level > 0) {
78		int pmulevel = pmu_backlight_get_level_brightness(level);
79
80		pmu_request(&req, NULL, 2, PMU_BACKLIGHT_BRIGHT, pmulevel);
81		pmu_wait_complete(&req);
82
83		pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
84			PMU_POW_BACKLIGHT | PMU_POW_ON);
85		pmu_wait_complete(&req);
86	} else {
87		pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
88			PMU_POW_BACKLIGHT | PMU_POW_OFF);
89		pmu_wait_complete(&req);
90	}
91
92	return 0;
93}
94
95static int pmu_backlight_update_status(struct backlight_device *bd)
96{
97	unsigned long flags;
98	int rc = 0;
99
100	spin_lock_irqsave(&pmu_backlight_lock, flags);
101	/* Don't update brightness when sleeping */
102	if (!sleeping)
103		rc = __pmu_backlight_update_status(bd);
104	spin_unlock_irqrestore(&pmu_backlight_lock, flags);
105	return rc;
106}
107
108
109static const struct backlight_ops pmu_backlight_data = {
110	.update_status	= pmu_backlight_update_status,
111
112};
113
114#ifdef CONFIG_PM
115void pmu_backlight_set_sleep(int sleep)
116{
117	unsigned long flags;
118
119	spin_lock_irqsave(&pmu_backlight_lock, flags);
120	sleeping = sleep;
121	if (pmac_backlight && uses_pmu_bl) {
122		if (sleep) {
123			struct adb_request req;
124
125			pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
126				    PMU_POW_BACKLIGHT | PMU_POW_OFF);
127			pmu_wait_complete(&req);
128		} else
129			__pmu_backlight_update_status(pmac_backlight);
130	}
131	spin_unlock_irqrestore(&pmu_backlight_lock, flags);
132}
133#endif /* CONFIG_PM */
134
135void __init pmu_backlight_init(void)
136{
137	struct backlight_properties props;
138	struct backlight_device *bd;
139	char name[10];
140	int level, autosave;
141
142	/* Special case for the old PowerBook since I can't test on it */
143	autosave =
144		of_machine_is_compatible("AAPL,3400/2400") ||
145		of_machine_is_compatible("AAPL,3500");
146
147	if (!autosave &&
148	    !pmac_has_backlight_type("pmu") &&
149	    !of_machine_is_compatible("AAPL,PowerBook1998") &&
150	    !of_machine_is_compatible("PowerBook1,1"))
151		return;
152
153	snprintf(name, sizeof(name), "pmubl");
154
155	memset(&props, 0, sizeof(struct backlight_properties));
156	props.type = BACKLIGHT_PLATFORM;
157	props.max_brightness = FB_BACKLIGHT_LEVELS - 1;
158	bd = backlight_device_register(name, NULL, NULL, &pmu_backlight_data,
159				       &props);
160	if (IS_ERR(bd)) {
161		printk(KERN_ERR "PMU Backlight registration failed\n");
162		return;
163	}
164	uses_pmu_bl = 1;
165	pmu_backlight_init_curve(0x7F, 0x46, 0x0E);
166
167	level = bd->props.max_brightness;
168
169	if (autosave) {
170		/* read autosaved value if available */
171		struct adb_request req;
172		pmu_request(&req, NULL, 2, 0xd9, 0);
173		pmu_wait_complete(&req);
174
175		level = pmu_backlight_curve_lookup(
176				(req.reply[0] >> 4) *
177				bd->props.max_brightness / 15);
178	}
179
180	bd->props.brightness = level;
181	bd->props.power = FB_BLANK_UNBLANK;
182	backlight_update_status(bd);
183
184	printk(KERN_INFO "PMU Backlight initialized (%s)\n", name);
185}
186