1 // SPDX-License-Identifier: GPL-2.0+
3 * work_92105 display support
5 * (C) Copyright 2014 DENX Software Engineering GmbH
6 * Written-by: Albert ARIBAUD <albert.aribaud@3adev.fr>
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.
14 #include <asm/arch/sys_proto.h>
15 #include <asm/arch/cpu.h>
16 #include <asm/arch/emc.h>
24 * GPO 15 in port 3 is gpio 3*32+15 = 111
30 * MAX6957AAX registers that we will be using
33 #define MAX6957_CONF 0x04
35 #define MAX6957_CONF_08_11 0x0A
36 #define MAX6957_CONF_12_15 0x0B
37 #define MAX6957_CONF_16_19 0x0C
40 * Individual gpio ports (one per gpio) to HD44780
43 #define MAX6957AAX_HD44780_RS 0x29
44 #define MAX6957AAX_HD44780_R_W 0x2A
45 #define MAX6957AAX_HD44780_EN 0x2B
46 #define MAX6957AAX_HD44780_DATA 0x4C
49 * Display controller instructions
52 /* Function set: eight bits, two lines, 8-dot font */
53 #define HD44780_FUNCTION_SET 0x38
55 /* Display ON / OFF: turn display on */
56 #define HD44780_DISPLAY_ON_OFF_CONTROL 0x0C
58 /* Entry mode: increment */
59 #define HD44780_ENTRY_MODE_SET 0x06
62 #define HD44780_CLEAR_DISPLAY 0x01
64 /* Set DDRAM addr (to be ORed with exact address) */
65 #define HD44780_SET_DDRAM_ADDR 0x80
67 /* Set CGRAM addr (to be ORed with exact address) */
68 #define HD44780_SET_CGRAM_ADDR 0x40
71 * Default value for contrats
74 #define CONTRAST_DEFAULT 25
77 * Define slave as a module-wide local to save passing it around,
78 * plus we will need it after init for the "hd44780" command.
81 static struct spi_slave *slave;
84 * Write a value into a MAX6957AAX register.
87 static void max6957aax_write(uint8_t reg, uint8_t value)
93 gpio_set_value(GPO_15, 0);
94 /* do SPI read/write (passing din==dout is OK) */
95 spi_xfer(slave, 16, dout, dout, SPI_XFER_BEGIN | SPI_XFER_END);
96 gpio_set_value(GPO_15, 1);
100 * Read a value from a MAX6957AAX register.
102 * According to the MAX6957AAX datasheet, we should release the chip
103 * select halfway through the read sequence, when the actual register
104 * value is read; but the WORK_92105 hardware prevents the MAX6957AAX
105 * SPI OUT from reaching the LPC32XX SIP MISO if chip is not selected.
106 * so let's release the CS an hold it again while reading the result.
109 static uint8_t max6957aax_read(uint8_t reg)
111 uint8_t dout[2], din[2];
113 /* send read command */
114 dout[0] = reg | 0x80; /* set bit 7 to indicate read */
116 gpio_set_value(GPO_15, 0);
117 /* do SPI read/write (passing din==dout is OK) */
118 spi_xfer(slave, 16, dout, dout, SPI_XFER_BEGIN | SPI_XFER_END);
119 /* latch read command */
120 gpio_set_value(GPO_15, 1);
121 /* read register -- din = noop on xmit, din[1] = reg on recv */
124 gpio_set_value(GPO_15, 0);
125 /* do SPI read/write (passing din==dout is OK) */
126 spi_xfer(slave, 16, din, din, SPI_XFER_BEGIN | SPI_XFER_END);
128 gpio_set_value(GPO_15, 1);
132 static void hd44780_instruction(unsigned long instruction)
134 max6957aax_write(MAX6957AAX_HD44780_RS, 0);
135 max6957aax_write(MAX6957AAX_HD44780_R_W, 0);
136 max6957aax_write(MAX6957AAX_HD44780_EN, 1);
137 max6957aax_write(MAX6957AAX_HD44780_DATA, instruction);
138 max6957aax_write(MAX6957AAX_HD44780_EN, 0);
139 /* HD44780 takes 37 us for most instructions, 1520 for clear */
140 if (instruction == HD44780_CLEAR_DISPLAY)
146 static void hd44780_write_char(char c)
148 max6957aax_write(MAX6957AAX_HD44780_RS, 1);
149 max6957aax_write(MAX6957AAX_HD44780_R_W, 0);
150 max6957aax_write(MAX6957AAX_HD44780_EN, 1);
151 max6957aax_write(MAX6957AAX_HD44780_DATA, c);
152 max6957aax_write(MAX6957AAX_HD44780_EN, 0);
153 /* HD44780 takes 37 us to write to DDRAM or CGRAM */
157 static void hd44780_write_str(char *s)
159 max6957aax_write(MAX6957AAX_HD44780_RS, 1);
160 max6957aax_write(MAX6957AAX_HD44780_R_W, 0);
162 max6957aax_write(MAX6957AAX_HD44780_EN, 1);
163 max6957aax_write(MAX6957AAX_HD44780_DATA, *s);
164 max6957aax_write(MAX6957AAX_HD44780_EN, 0);
166 /* HD44780 takes 37 us to write to DDRAM or CGRAM */
172 * Existing user code might expect these custom characters to be
173 * recognized and displayed on the LCD
176 static u8 char_gen_chars[] = {
177 /* #8, empty rectangle */
178 0x1F, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x1F,
179 /* #9, filled right arrow */
180 0x10, 0x18, 0x1C, 0x1E, 0x1C, 0x18, 0x10, 0x00,
181 /* #10, filled left arrow */
182 0x01, 0x03, 0x07, 0x0F, 0x07, 0x03, 0x01, 0x00,
183 /* #11, up and down arrow */
184 0x04, 0x0E, 0x1F, 0x00, 0x00, 0x1F, 0x0E, 0x04,
185 /* #12, plus/minus */
186 0x04, 0x04, 0x1F, 0x04, 0x04, 0x00, 0x1F, 0x00,
187 /* #13, fat exclamation mark */
188 0x06, 0x06, 0x06, 0x06, 0x00, 0x06, 0x06, 0x00,
189 /* #14, empty square */
190 0x00, 0x1F, 0x11, 0x11, 0x11, 0x1F, 0x00, 0x00,
191 /* #15, struck out square */
192 0x00, 0x1F, 0x19, 0x15, 0x13, 0x1F, 0x00, 0x00,
195 static void hd44780_init_char_gen(void)
199 hd44780_instruction(HD44780_SET_CGRAM_ADDR);
201 for (i = 0; i < sizeof(char_gen_chars); i++)
202 hd44780_write_char(char_gen_chars[i]);
204 hd44780_instruction(HD44780_SET_DDRAM_ADDR);
207 void work_92105_display_init(void)
210 char *display_contrast_str;
211 uint8_t display_contrast = CONTRAST_DEFAULT;
212 uint8_t enable_backlight = 0x96;
214 slave = spi_setup_slave(0, 0, 500000, 0);
217 printf("Failed to set up SPI slave\n");
221 claim_err = spi_claim_bus(slave);
224 debug("Failed to claim SPI bus: %d\n", claim_err);
226 /* enable backlight */
227 i2c_write(0x2c, 0x01, 1, &enable_backlight, 1);
229 /* set display contrast */
230 display_contrast_str = env_get("fwopt_dispcontrast");
231 if (display_contrast_str)
232 display_contrast = simple_strtoul(display_contrast_str,
234 i2c_write(0x2c, 0x00, 1, &display_contrast, 1);
236 /* request GPO_15 as an output initially set to 1 */
237 gpio_request(GPO_15, "MAX6957_nCS");
238 gpio_direction_output(GPO_15, 1);
240 /* enable MAX6957 portexpander */
241 max6957aax_write(MAX6957_CONF, 0x01);
242 /* configure pin 8 as input, pins 9..19 as outputs */
243 max6957aax_write(MAX6957_CONF_08_11, 0x56);
244 max6957aax_write(MAX6957_CONF_12_15, 0x55);
245 max6957aax_write(MAX6957_CONF_16_19, 0x55);
247 /* initialize HD44780 */
248 max6957aax_write(MAX6957AAX_HD44780_EN, 0);
249 hd44780_instruction(HD44780_FUNCTION_SET);
250 hd44780_instruction(HD44780_DISPLAY_ON_OFF_CONTROL);
251 hd44780_instruction(HD44780_ENTRY_MODE_SET);
253 /* write custom character glyphs */
254 hd44780_init_char_gen();
256 /* Show U-Boot version, date and time as a sign-of-life */
257 hd44780_instruction(HD44780_CLEAR_DISPLAY);
258 hd44780_instruction(HD44780_SET_DDRAM_ADDR | 0);
259 hd44780_write_str(U_BOOT_VERSION);
260 hd44780_instruction(HD44780_SET_DDRAM_ADDR | 64);
261 hd44780_write_str(U_BOOT_DATE);
262 hd44780_instruction(HD44780_SET_DDRAM_ADDR | 64 | 20);
263 hd44780_write_str(U_BOOT_TIME);
266 #ifdef CONFIG_CMD_MAX6957
268 static int do_max6957aax(cmd_tbl_t *cmdtp, int flag, int argc,
274 return CMD_RET_USAGE;
275 switch (argv[1][0]) {
278 reg = simple_strtoul(argv[2], NULL, 0);
279 val = max6957aax_read(reg);
280 printf("MAX6957 reg 0x%02x read 0x%02x\n", reg, val);
283 reg = simple_strtoul(argv[1], NULL, 0);
284 val = simple_strtoul(argv[2], NULL, 0);
285 max6957aax_write(reg, val);
286 printf("MAX6957 reg 0x%02x wrote 0x%02x\n", reg, val);
292 #ifdef CONFIG_SYS_LONGHELP
293 static char max6957aax_help_text[] =
294 "max6957aax - write or read display register:\n"
295 "\tmax6957aax R|r reg - read display register;\n"
296 "\tmax6957aax reg val - write display register.";
300 max6957aax, 6, 1, do_max6957aax,
301 "SPI MAX6957 display write/read",
304 #endif /* CONFIG_CMD_MAX6957 */
306 #ifdef CONFIG_CMD_HD44760
309 * We need the HUSH parser because we need string arguments, and
310 * only HUSH can understand them.
313 #if !defined(CONFIG_HUSH_PARSER)
314 #error CONFIG_CMD_HD44760 requires CONFIG_HUSH_PARSER
317 static int do_hd44780(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
322 return CMD_RET_USAGE;
326 if (strcasecmp(cmd, "cmd") == 0)
327 hd44780_instruction(simple_strtol(argv[2], NULL, 0));
328 else if (strcasecmp(cmd, "data") == 0)
329 hd44780_write_char(simple_strtol(argv[2], NULL, 0));
330 else if (strcasecmp(cmd, "str") == 0)
331 hd44780_write_str(argv[2]);
335 #ifdef CONFIG_SYS_LONGHELP
336 static char hd44780_help_text[] =
337 "hd44780 - control LCD driver:\n"
338 "\thd44780 cmd <val> - send command <val> to driver;\n"
339 "\thd44780 data <val> - send data <val> to driver;\n"
340 "\thd44780 str \"<text>\" - send \"<text>\" to driver.";
344 hd44780, 6, 1, do_hd44780,
345 "HD44780 LCD driver control",
348 #endif /* CONFIG_CMD_HD44760 */