1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *    Filename: cfag12864b-example.c
4  *     Version: 0.1.0
5  * Description: cfag12864b LCD userspace example program
6  *
7  *      Author: Copyright (C) Miguel Ojeda Sandonis
8  *        Date: 2006-10-31
9  */
10 
11 /*
12  * ------------------------
13  * start of cfag12864b code
14  * ------------------------
15  */
16 
17 #include <string.h>
18 #include <fcntl.h>
19 #include <unistd.h>
20 #include <sys/types.h>
21 #include <sys/stat.h>
22 #include <sys/mman.h>
23 
24 #define CFAG12864B_WIDTH		(128)
25 #define CFAG12864B_HEIGHT		(64)
26 #define CFAG12864B_SIZE			(128 * 64 / 8)
27 #define CFAG12864B_BPB			(8)
28 #define CFAG12864B_ADDRESS(x, y)	((y) * CFAG12864B_WIDTH / \
29 					CFAG12864B_BPB + (x) / CFAG12864B_BPB)
30 #define CFAG12864B_BIT(n)		(((unsigned char) 1) << (n))
31 
32 #undef CFAG12864B_DOCHECK
33 #ifdef CFAG12864B_DOCHECK
34 	#define CFAG12864B_CHECK(x, y)		((x) < CFAG12864B_WIDTH && \
35 						(y) < CFAG12864B_HEIGHT)
36 #else
37 	#define CFAG12864B_CHECK(x, y)		(1)
38 #endif
39 
40 int cfag12864b_fd;
41 unsigned char * cfag12864b_mem;
42 unsigned char cfag12864b_buffer[CFAG12864B_SIZE];
43 
44 /*
45  * init a cfag12864b framebuffer device
46  *
47  * No error:       return = 0
48  * Unable to open: return = -1
49  * Unable to mmap: return = -2
50  */
51 static int cfag12864b_init(char *path)
52 {
53 	cfag12864b_fd = open(path, O_RDWR);
54 	if (cfag12864b_fd == -1)
55 		return -1;
56 
57 	cfag12864b_mem = mmap(0, CFAG12864B_SIZE, PROT_READ | PROT_WRITE,
58 		MAP_SHARED, cfag12864b_fd, 0);
59 	if (cfag12864b_mem == MAP_FAILED) {
60 		close(cfag12864b_fd);
61 		return -2;
62 	}
63 
64 	return 0;
65 }
66 
67 /*
68  * exit a cfag12864b framebuffer device
69  */
70 static void cfag12864b_exit(void)
71 {
72 	munmap(cfag12864b_mem, CFAG12864B_SIZE);
73 	close(cfag12864b_fd);
74 }
75 
76 /*
77  * set (x, y) pixel
78  */
79 static void cfag12864b_set(unsigned char x, unsigned char y)
80 {
81 	if (CFAG12864B_CHECK(x, y))
82 		cfag12864b_buffer[CFAG12864B_ADDRESS(x, y)] |=
83 			CFAG12864B_BIT(x % CFAG12864B_BPB);
84 }
85 
86 /*
87  * unset (x, y) pixel
88  */
89 static void cfag12864b_unset(unsigned char x, unsigned char y)
90 {
91 	if (CFAG12864B_CHECK(x, y))
92 		cfag12864b_buffer[CFAG12864B_ADDRESS(x, y)] &=
93 			~CFAG12864B_BIT(x % CFAG12864B_BPB);
94 }
95 
96 /*
97  * is set (x, y) pixel?
98  *
99  * Pixel off: return = 0
100  * Pixel on:  return = 1
101  */
102 static unsigned char cfag12864b_isset(unsigned char x, unsigned char y)
103 {
104 	if (CFAG12864B_CHECK(x, y))
105 		if (cfag12864b_buffer[CFAG12864B_ADDRESS(x, y)] &
106 			CFAG12864B_BIT(x % CFAG12864B_BPB))
107 			return 1;
108 
109 	return 0;
110 }
111 
112 /*
113  * not (x, y) pixel
114  */
115 static void cfag12864b_not(unsigned char x, unsigned char y)
116 {
117 	if (cfag12864b_isset(x, y))
118 		cfag12864b_unset(x, y);
119 	else
120 		cfag12864b_set(x, y);
121 }
122 
123 /*
124  * fill (set all pixels)
125  */
126 static void cfag12864b_fill(void)
127 {
128 	unsigned short i;
129 
130 	for (i = 0; i < CFAG12864B_SIZE; i++)
131 		cfag12864b_buffer[i] = 0xFF;
132 }
133 
134 /*
135  * clear (unset all pixels)
136  */
137 static void cfag12864b_clear(void)
138 {
139 	unsigned short i;
140 
141 	for (i = 0; i < CFAG12864B_SIZE; i++)
142 		cfag12864b_buffer[i] = 0;
143 }
144 
145 /*
146  * format a [128*64] matrix
147  *
148  * Pixel off: src[i] = 0
149  * Pixel on:  src[i] > 0
150  */
151 static void cfag12864b_format(unsigned char * matrix)
152 {
153 	unsigned char i, j, n;
154 
155 	for (i = 0; i < CFAG12864B_HEIGHT; i++)
156 	for (j = 0; j < CFAG12864B_WIDTH / CFAG12864B_BPB; j++) {
157 		cfag12864b_buffer[i * CFAG12864B_WIDTH / CFAG12864B_BPB +
158 			j] = 0;
159 		for (n = 0; n < CFAG12864B_BPB; n++)
160 			if (matrix[i * CFAG12864B_WIDTH +
161 				j * CFAG12864B_BPB + n])
162 				cfag12864b_buffer[i * CFAG12864B_WIDTH /
163 					CFAG12864B_BPB + j] |=
164 					CFAG12864B_BIT(n);
165 	}
166 }
167 
168 /*
169  * blit buffer to lcd
170  */
171 static void cfag12864b_blit(void)
172 {
173 	memcpy(cfag12864b_mem, cfag12864b_buffer, CFAG12864B_SIZE);
174 }
175 
176 /*
177  * ----------------------
178  * end of cfag12864b code
179  * ----------------------
180  */
181 
182 #include <stdio.h>
183 
184 #define EXAMPLES	6
185 
186 static void example(unsigned char n)
187 {
188 	unsigned short i, j;
189 	unsigned char matrix[CFAG12864B_WIDTH * CFAG12864B_HEIGHT];
190 
191 	if (n > EXAMPLES)
192 		return;
193 
194 	printf("Example %i/%i - ", n, EXAMPLES);
195 
196 	switch (n) {
197 	case 1:
198 		printf("Draw points setting bits");
199 		cfag12864b_clear();
200 		for (i = 0; i < CFAG12864B_WIDTH; i += 2)
201 			for (j = 0; j < CFAG12864B_HEIGHT; j += 2)
202 				cfag12864b_set(i, j);
203 		break;
204 
205 	case 2:
206 		printf("Clear the LCD");
207 		cfag12864b_clear();
208 		break;
209 
210 	case 3:
211 		printf("Draw rows formatting a [128*64] matrix");
212 		memset(matrix, 0, CFAG12864B_WIDTH * CFAG12864B_HEIGHT);
213 		for (i = 0; i < CFAG12864B_WIDTH; i++)
214 			for (j = 0; j < CFAG12864B_HEIGHT; j += 2)
215 				matrix[j * CFAG12864B_WIDTH + i] = 1;
216 		cfag12864b_format(matrix);
217 		break;
218 
219 	case 4:
220 		printf("Fill the lcd");
221 		cfag12864b_fill();
222 		break;
223 
224 	case 5:
225 		printf("Draw columns unsetting bits");
226 		for (i = 0; i < CFAG12864B_WIDTH; i += 2)
227 			for (j = 0; j < CFAG12864B_HEIGHT; j++)
228 				cfag12864b_unset(i, j);
229 		break;
230 
231 	case 6:
232 		printf("Do negative not-ing all bits");
233 		for (i = 0; i < CFAG12864B_WIDTH; i++)
234 			for (j = 0; j < CFAG12864B_HEIGHT; j ++)
235 				cfag12864b_not(i, j);
236 		break;
237 	}
238 
239 	puts(" - [Press Enter]");
240 }
241 
242 int main(int argc, char *argv[])
243 {
244 	unsigned char n;
245 
246 	if (argc != 2) {
247 		printf(
248 			"Syntax:  %s fbdev\n"
249 			"Usually: /dev/fb0, /dev/fb1...\n", argv[0]);
250 		return -1;
251 	}
252 
253 	if (cfag12864b_init(argv[1])) {
254 		printf("Can't init %s fbdev\n", argv[1]);
255 		return -2;
256 	}
257 
258 	for (n = 1; n <= EXAMPLES; n++) {
259 		example(n);
260 		cfag12864b_blit();
261 		while (getchar() != '\n');
262 	}
263 
264 	cfag12864b_exit();
265 
266 	return 0;
267 }
268