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1 /*
2  * lws abstract display
3  *
4  * Copyright (C) 2019 - 2020 Andy Green <andy@warmcat.com>
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a copy
7  * of this software and associated documentation files (the "Software"), to
8  * deal in the Software without restriction, including without limitation the
9  * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
10  * sell copies of the Software, and to permit persons to whom the Software is
11  * furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice shall be included in
14  * all copies or substantial portions of the Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
22  * IN THE SOFTWARE.
23  */
24 
25 #if !defined(__LWS_DISPLAY_H__)
26 #define __LWS_DISPLAY_H__
27 
28 #include <stdint.h>
29 
30 typedef uint16_t lws_display_scalar;
31 
32 /*
33  * This is embedded in the actual display implementation object at the top,
34  * so a pointer to this can be cast to a pointer to the implementation object
35  * by any code that is specific to how it was implemented.
36  *
37  * Notice for the backlight / display intensity we contain pwm_ops... these can
38  * be some other pwm_ops like existing gpio pwm ops, or handled in a customized
39  * way like set oled contrast.  Either way, the pwm level is arrived at via a
40  * full set of lws_led_sequences capable of generic lws transitions
41  */
42 
43 typedef struct lws_display {
44 	int (*init)(const struct lws_display *disp);
45 	const lws_pwm_ops_t		*bl_pwm_ops;
46 	int (*contrast)(const struct lws_display *disp, uint8_t contrast);
47 	int (*blit)(const struct lws_display *disp, const uint8_t *src,
48 		    lws_display_scalar x, lws_display_scalar y,
49 		    lws_display_scalar w, lws_display_scalar h);
50 	int (*power)(const struct lws_display *disp, int state);
51 
52 	const lws_led_sequence_def_t	*bl_active;
53 	const lws_led_sequence_def_t	*bl_dim;
54 	const lws_led_sequence_def_t	*bl_transition;
55 
56 	void				*variant;
57 
58 	int				bl_index;
59 
60 	lws_display_scalar		w;
61 	/**< display surface width in pixels */
62 	lws_display_scalar		h;
63 	/**< display surface height in pixels */
64 
65 	uint8_t				latency_wake_ms;
66 	/**< ms required after wake from sleep before display usable again...
67 	 * delay bringing up the backlight for this amount of time on wake.
68 	 * This is managed via a sul on the event loop, not blocking. */
69 } lws_display_t;
70 
71 /*
72  * This contains dynamic data related to display state
73  */
74 
75 enum lws_display_controller_state {
76 	LWSDISPS_OFF,
77 	LWSDISPS_AUTODIMMED,	  /* is in pre- blanking static dim mode */
78 	LWSDISPS_BECOMING_ACTIVE, /* waiting for wake latency before active */
79 	LWSDISPS_ACTIVE,	  /* is active */
80 	LWSDISPS_GOING_OFF	  /* dimming then off */
81 };
82 
83 typedef struct lws_display_state {
84 
85 	lws_sorted_usec_list_t		sul_autodim;
86 	const lws_display_t		*disp;
87 	struct lws_context		*ctx;
88 
89 	int				autodim_ms;
90 	int				off_ms;
91 
92 	struct lws_led_state		*bl_lcs;
93 
94 	lws_led_state_chs_t		chs;
95 	/* set of sequencer transition channels */
96 
97 	enum lws_display_controller_state state;
98 
99 } lws_display_state_t;
100 
101 /**
102  * lws_display_state_init() - initialize display states
103  *
104  * \param lds: the display state object
105  * \param ctx: the lws context
106  * \param autodim_ms: ms since last active report to dim display (<0 = never)
107  * \param off_ms: ms since dim to turn display off (<0 = never)
108  * \param bl_lcs: the led controller instance that has the backlight
109  * \param disp: generic display object we belong to
110  *
111  * This initializes a display's state, and sets up the optional screen auto-dim
112  * and blanking on inactive, and gradual brightness change timer.
113  *
114  *  - auto-dim then off: set autodim to some ms and off_ms to some ms
115  *  - auto-dim only: set autodim to some ms and off_ms to -1
116  *  - off-only: set autodim to some ms and off_ms to 0
117  *  - neither: set both autodim and off_ms to -1
118  */
119 LWS_VISIBLE LWS_EXTERN void
120 lws_display_state_init(lws_display_state_t *lds, struct lws_context *ctx,
121 		       int autodim_ms, int off_ms, struct lws_led_state *bl_lcs,
122 		       const lws_display_t *disp);
123 
124 /**
125  * lws_display_state_set_brightness() - gradually change the brightness
126  *
127  * \param lds: the display state we are changing
128  * \param target: the target brightness to transition to
129  *
130  * Adjusts the brightness gradually twoards the target at 20Hz
131  */
132 LWS_VISIBLE LWS_EXTERN void
133 lws_display_state_set_brightness(lws_display_state_t *lds,
134 				 const lws_led_sequence_def_t *pwmseq);
135 
136 /*
137  * lws_display_state_active() - inform the system the display is active
138  *
139  * \param lds: the display state we are marking as active
140  *
141  * Resets the auto-dim and auto-off timers and makes sure the display is on and
142  * at the active brightness level
143  */
144 LWS_VISIBLE LWS_EXTERN void
145 lws_display_state_active(lws_display_state_t *lds);
146 
147 /*
148  * lws_display_state_off() - turns off the related display
149  *
150  * \param lds: the display state we are turning off
151  *
152  * Turns the display to least power mode or completely off if possible.
153  * Disables the timers related to dimming and blanking.
154  */
155 LWS_VISIBLE LWS_EXTERN void
156 lws_display_state_off(lws_display_state_t *lds);
157 
158 #endif
159