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