1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * work_92105 display support
4 *
5 * (C) Copyright 2014 DENX Software Engineering GmbH
6 * Written-by: Albert ARIBAUD <albert.aribaud@3adev.fr>
7 *
8 * The work_92105 display is a HD44780-compatible module
9 * controlled through a MAX6957AAX SPI port expander, two
10 * MAX518 I2C DACs and native LPC32xx GPO 15.
11 */
12
13 #include <common.h>
14 #include <asm/arch/sys_proto.h>
15 #include <asm/arch/cpu.h>
16 #include <asm/arch/emc.h>
17 #include <asm/gpio.h>
18 #include <spi.h>
19 #include <i2c.h>
20 #include <timestamp.h>
21 #include <version.h>
22 #include <vsprintf.h>
23
24 /*
25 * GPO 15 in port 3 is gpio 3*32+15 = 111
26 */
27
28 #define GPO_15 111
29
30 /**
31 * MAX6957AAX registers that we will be using
32 */
33
34 #define MAX6957_CONF 0x04
35
36 #define MAX6957_CONF_08_11 0x0A
37 #define MAX6957_CONF_12_15 0x0B
38 #define MAX6957_CONF_16_19 0x0C
39
40 /**
41 * Individual gpio ports (one per gpio) to HD44780
42 */
43
44 #define MAX6957AAX_HD44780_RS 0x29
45 #define MAX6957AAX_HD44780_R_W 0x2A
46 #define MAX6957AAX_HD44780_EN 0x2B
47 #define MAX6957AAX_HD44780_DATA 0x4C
48
49 /**
50 * Display controller instructions
51 */
52
53 /* Function set: eight bits, two lines, 8-dot font */
54 #define HD44780_FUNCTION_SET 0x38
55
56 /* Display ON / OFF: turn display on */
57 #define HD44780_DISPLAY_ON_OFF_CONTROL 0x0C
58
59 /* Entry mode: increment */
60 #define HD44780_ENTRY_MODE_SET 0x06
61
62 /* Clear */
63 #define HD44780_CLEAR_DISPLAY 0x01
64
65 /* Set DDRAM addr (to be ORed with exact address) */
66 #define HD44780_SET_DDRAM_ADDR 0x80
67
68 /* Set CGRAM addr (to be ORed with exact address) */
69 #define HD44780_SET_CGRAM_ADDR 0x40
70
71 /**
72 * Default value for contrats
73 */
74
75 #define CONTRAST_DEFAULT 25
76
77 /**
78 * Define slave as a module-wide local to save passing it around,
79 * plus we will need it after init for the "hd44780" command.
80 */
81
82 static struct spi_slave *slave;
83
84 /*
85 * Write a value into a MAX6957AAX register.
86 */
87
max6957aax_write(uint8_t reg,uint8_t value)88 static void max6957aax_write(uint8_t reg, uint8_t value)
89 {
90 uint8_t dout[2];
91
92 dout[0] = reg;
93 dout[1] = value;
94 gpio_set_value(GPO_15, 0);
95 /* do SPI read/write (passing din==dout is OK) */
96 spi_xfer(slave, 16, dout, dout, SPI_XFER_BEGIN | SPI_XFER_END);
97 gpio_set_value(GPO_15, 1);
98 }
99
100 /*
101 * Read a value from a MAX6957AAX register.
102 *
103 * According to the MAX6957AAX datasheet, we should release the chip
104 * select halfway through the read sequence, when the actual register
105 * value is read; but the WORK_92105 hardware prevents the MAX6957AAX
106 * SPI OUT from reaching the LPC32XX SIP MISO if chip is not selected.
107 * so let's release the CS an hold it again while reading the result.
108 */
109
max6957aax_read(uint8_t reg)110 static uint8_t max6957aax_read(uint8_t reg)
111 {
112 uint8_t dout[2], din[2];
113
114 /* send read command */
115 dout[0] = reg | 0x80; /* set bit 7 to indicate read */
116 dout[1] = 0;
117 gpio_set_value(GPO_15, 0);
118 /* do SPI read/write (passing din==dout is OK) */
119 spi_xfer(slave, 16, dout, dout, SPI_XFER_BEGIN | SPI_XFER_END);
120 /* latch read command */
121 gpio_set_value(GPO_15, 1);
122 /* read register -- din = noop on xmit, din[1] = reg on recv */
123 din[0] = 0;
124 din[1] = 0;
125 gpio_set_value(GPO_15, 0);
126 /* do SPI read/write (passing din==dout is OK) */
127 spi_xfer(slave, 16, din, din, SPI_XFER_BEGIN | SPI_XFER_END);
128 /* end of read. */
129 gpio_set_value(GPO_15, 1);
130 return din[1];
131 }
132
hd44780_instruction(unsigned long instruction)133 static void hd44780_instruction(unsigned long instruction)
134 {
135 max6957aax_write(MAX6957AAX_HD44780_RS, 0);
136 max6957aax_write(MAX6957AAX_HD44780_R_W, 0);
137 max6957aax_write(MAX6957AAX_HD44780_EN, 1);
138 max6957aax_write(MAX6957AAX_HD44780_DATA, instruction);
139 max6957aax_write(MAX6957AAX_HD44780_EN, 0);
140 /* HD44780 takes 37 us for most instructions, 1520 for clear */
141 if (instruction == HD44780_CLEAR_DISPLAY)
142 udelay(2000);
143 else
144 udelay(100);
145 }
146
hd44780_write_char(char c)147 static void hd44780_write_char(char c)
148 {
149 max6957aax_write(MAX6957AAX_HD44780_RS, 1);
150 max6957aax_write(MAX6957AAX_HD44780_R_W, 0);
151 max6957aax_write(MAX6957AAX_HD44780_EN, 1);
152 max6957aax_write(MAX6957AAX_HD44780_DATA, c);
153 max6957aax_write(MAX6957AAX_HD44780_EN, 0);
154 /* HD44780 takes 37 us to write to DDRAM or CGRAM */
155 udelay(100);
156 }
157
hd44780_write_str(char * s)158 static void hd44780_write_str(char *s)
159 {
160 max6957aax_write(MAX6957AAX_HD44780_RS, 1);
161 max6957aax_write(MAX6957AAX_HD44780_R_W, 0);
162 while (*s) {
163 max6957aax_write(MAX6957AAX_HD44780_EN, 1);
164 max6957aax_write(MAX6957AAX_HD44780_DATA, *s);
165 max6957aax_write(MAX6957AAX_HD44780_EN, 0);
166 s++;
167 /* HD44780 takes 37 us to write to DDRAM or CGRAM */
168 udelay(100);
169 }
170 }
171
172 /*
173 * Existing user code might expect these custom characters to be
174 * recognized and displayed on the LCD
175 */
176
177 static u8 char_gen_chars[] = {
178 /* #8, empty rectangle */
179 0x1F, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x1F,
180 /* #9, filled right arrow */
181 0x10, 0x18, 0x1C, 0x1E, 0x1C, 0x18, 0x10, 0x00,
182 /* #10, filled left arrow */
183 0x01, 0x03, 0x07, 0x0F, 0x07, 0x03, 0x01, 0x00,
184 /* #11, up and down arrow */
185 0x04, 0x0E, 0x1F, 0x00, 0x00, 0x1F, 0x0E, 0x04,
186 /* #12, plus/minus */
187 0x04, 0x04, 0x1F, 0x04, 0x04, 0x00, 0x1F, 0x00,
188 /* #13, fat exclamation mark */
189 0x06, 0x06, 0x06, 0x06, 0x00, 0x06, 0x06, 0x00,
190 /* #14, empty square */
191 0x00, 0x1F, 0x11, 0x11, 0x11, 0x1F, 0x00, 0x00,
192 /* #15, struck out square */
193 0x00, 0x1F, 0x19, 0x15, 0x13, 0x1F, 0x00, 0x00,
194 };
195
hd44780_init_char_gen(void)196 static void hd44780_init_char_gen(void)
197 {
198 int i;
199
200 hd44780_instruction(HD44780_SET_CGRAM_ADDR);
201
202 for (i = 0; i < sizeof(char_gen_chars); i++)
203 hd44780_write_char(char_gen_chars[i]);
204
205 hd44780_instruction(HD44780_SET_DDRAM_ADDR);
206 }
207
work_92105_display_init(void)208 void work_92105_display_init(void)
209 {
210 int claim_err;
211 char *display_contrast_str;
212 uint8_t display_contrast = CONTRAST_DEFAULT;
213 uint8_t enable_backlight = 0x96;
214
215 slave = spi_setup_slave(0, 0, 500000, 0);
216
217 if (!slave) {
218 printf("Failed to set up SPI slave\n");
219 return;
220 }
221
222 claim_err = spi_claim_bus(slave);
223
224 if (claim_err)
225 debug("Failed to claim SPI bus: %d\n", claim_err);
226
227 /* enable backlight */
228 i2c_write(0x2c, 0x01, 1, &enable_backlight, 1);
229
230 /* set display contrast */
231 display_contrast_str = env_get("fwopt_dispcontrast");
232 if (display_contrast_str)
233 display_contrast = simple_strtoul(display_contrast_str,
234 NULL, 10);
235 i2c_write(0x2c, 0x00, 1, &display_contrast, 1);
236
237 /* request GPO_15 as an output initially set to 1 */
238 gpio_request(GPO_15, "MAX6957_nCS");
239 gpio_direction_output(GPO_15, 1);
240
241 /* enable MAX6957 portexpander */
242 max6957aax_write(MAX6957_CONF, 0x01);
243 /* configure pin 8 as input, pins 9..19 as outputs */
244 max6957aax_write(MAX6957_CONF_08_11, 0x56);
245 max6957aax_write(MAX6957_CONF_12_15, 0x55);
246 max6957aax_write(MAX6957_CONF_16_19, 0x55);
247
248 /* initialize HD44780 */
249 max6957aax_write(MAX6957AAX_HD44780_EN, 0);
250 hd44780_instruction(HD44780_FUNCTION_SET);
251 hd44780_instruction(HD44780_DISPLAY_ON_OFF_CONTROL);
252 hd44780_instruction(HD44780_ENTRY_MODE_SET);
253
254 /* write custom character glyphs */
255 hd44780_init_char_gen();
256
257 /* Show U-Boot version, date and time as a sign-of-life */
258 hd44780_instruction(HD44780_CLEAR_DISPLAY);
259 hd44780_instruction(HD44780_SET_DDRAM_ADDR | 0);
260 hd44780_write_str(U_BOOT_VERSION);
261 hd44780_instruction(HD44780_SET_DDRAM_ADDR | 64);
262 hd44780_write_str(U_BOOT_DATE);
263 hd44780_instruction(HD44780_SET_DDRAM_ADDR | 64 | 20);
264 hd44780_write_str(U_BOOT_TIME);
265 }
266
267 #ifdef CONFIG_CMD_MAX6957
268
do_max6957aax(cmd_tbl_t * cmdtp,int flag,int argc,char * const argv[])269 static int do_max6957aax(cmd_tbl_t *cmdtp, int flag, int argc,
270 char *const argv[])
271 {
272 int reg, val;
273
274 if (argc != 3)
275 return CMD_RET_USAGE;
276 switch (argv[1][0]) {
277 case 'r':
278 case 'R':
279 reg = simple_strtoul(argv[2], NULL, 0);
280 val = max6957aax_read(reg);
281 printf("MAX6957 reg 0x%02x read 0x%02x\n", reg, val);
282 return 0;
283 default:
284 reg = simple_strtoul(argv[1], NULL, 0);
285 val = simple_strtoul(argv[2], NULL, 0);
286 max6957aax_write(reg, val);
287 printf("MAX6957 reg 0x%02x wrote 0x%02x\n", reg, val);
288 return 0;
289 }
290 return 1;
291 }
292
293 #ifdef CONFIG_SYS_LONGHELP
294 static char max6957aax_help_text[] =
295 "max6957aax - write or read display register:\n"
296 "\tmax6957aax R|r reg - read display register;\n"
297 "\tmax6957aax reg val - write display register.";
298 #endif
299
300 U_BOOT_CMD(
301 max6957aax, 6, 1, do_max6957aax,
302 "SPI MAX6957 display write/read",
303 max6957aax_help_text
304 );
305 #endif /* CONFIG_CMD_MAX6957 */
306
307 #ifdef CONFIG_CMD_HD44760
308
309 /*
310 * We need the HUSH parser because we need string arguments, and
311 * only HUSH can understand them.
312 */
313
314 #if !defined(CONFIG_HUSH_PARSER)
315 #error CONFIG_CMD_HD44760 requires CONFIG_HUSH_PARSER
316 #endif
317
do_hd44780(cmd_tbl_t * cmdtp,int flag,int argc,char * const argv[])318 static int do_hd44780(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
319 {
320 char *cmd;
321
322 if (argc != 3)
323 return CMD_RET_USAGE;
324
325 cmd = argv[1];
326
327 if (strcasecmp(cmd, "cmd") == 0)
328 hd44780_instruction(simple_strtol(argv[2], NULL, 0));
329 else if (strcasecmp(cmd, "data") == 0)
330 hd44780_write_char(simple_strtol(argv[2], NULL, 0));
331 else if (strcasecmp(cmd, "str") == 0)
332 hd44780_write_str(argv[2]);
333 return 0;
334 }
335
336 #ifdef CONFIG_SYS_LONGHELP
337 static char hd44780_help_text[] =
338 "hd44780 - control LCD driver:\n"
339 "\thd44780 cmd <val> - send command <val> to driver;\n"
340 "\thd44780 data <val> - send data <val> to driver;\n"
341 "\thd44780 str \"<text>\" - send \"<text>\" to driver.";
342 #endif
343
344 U_BOOT_CMD(
345 hd44780, 6, 1, do_hd44780,
346 "HD44780 LCD driver control",
347 hd44780_help_text
348 );
349 #endif /* CONFIG_CMD_HD44760 */
350