board/work-microwave/work_92105/work_92105_display.c

   1 /*
   2  * work_92105 display support
   3  *
   4  * (C) Copyright 2014  DENX Software Engineering GmbH
   5  * Written-by: Albert ARIBAUD <albert.aribaud@3adev.fr>
   6  *
   7  * The work_92105 display is a HD44780-compatible module
   8  * controlled through a MAX6957AAX SPI port expander, two
   9  * MAX518 I2C DACs and native LPC32xx GPO 15.
  10  *
  11  * SPDX-License-Identifier:     GPL-2.0+
  12  */
  13
  14 #include <common.h>
  15 #include <asm/arch/sys_proto.h>
  16 #include <asm/arch/cpu.h>
  17 #include <asm/arch/emc.h>
  18 #include <asm/gpio.h>
  19 #include <spi.h>
  20 #include <i2c.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
  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
 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
 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
 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
 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
 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
 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
 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
 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 */