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// SPDX-License-Identifier: GPL-2.0+
/*
* work_92105 display support
*
* (C) Copyright 2014 DENX Software Engineering GmbH
* Written-by: Albert ARIBAUD <albert.aribaud@3adev.fr>
*
* The work_92105 display is a HD44780-compatible module
* controlled through a MAX6957AAX SPI port expander, two
* MAX518 I2C DACs and native LPC32xx GPO 15.
*/
#include <common.h>
#include <asm/arch/sys_proto.h>
#include <asm/arch/cpu.h>
#include <asm/arch/emc.h>
#include <asm/gpio.h>
#include <spi.h>
#include <i2c.h>
#include <version.h>
#include <vsprintf.h>
/*
* GPO 15 in port 3 is gpio 3*32+15 = 111
*/
#define GPO_15 111
/**
* MAX6957AAX registers that we will be using
*/
#define MAX6957_CONF 0x04
#define MAX6957_CONF_08_11 0x0A
#define MAX6957_CONF_12_15 0x0B
#define MAX6957_CONF_16_19 0x0C
/**
* Individual gpio ports (one per gpio) to HD44780
*/
#define MAX6957AAX_HD44780_RS 0x29
#define MAX6957AAX_HD44780_R_W 0x2A
#define MAX6957AAX_HD44780_EN 0x2B
#define MAX6957AAX_HD44780_DATA 0x4C
/**
* Display controller instructions
*/
/* Function set: eight bits, two lines, 8-dot font */
#define HD44780_FUNCTION_SET 0x38
/* Display ON / OFF: turn display on */
#define HD44780_DISPLAY_ON_OFF_CONTROL 0x0C
/* Entry mode: increment */
#define HD44780_ENTRY_MODE_SET 0x06
/* Clear */
#define HD44780_CLEAR_DISPLAY 0x01
/* Set DDRAM addr (to be ORed with exact address) */
#define HD44780_SET_DDRAM_ADDR 0x80
/* Set CGRAM addr (to be ORed with exact address) */
#define HD44780_SET_CGRAM_ADDR 0x40
/**
* Default value for contrats
*/
#define CONTRAST_DEFAULT 25
/**
* Define slave as a module-wide local to save passing it around,
* plus we will need it after init for the "hd44780" command.
*/
static struct spi_slave *slave;
/*
* Write a value into a MAX6957AAX register.
*/
static void max6957aax_write(uint8_t reg, uint8_t value)
{
uint8_t dout[2];
dout[0] = reg;
dout[1] = value;
gpio_set_value(GPO_15, 0);
/* do SPI read/write (passing din==dout is OK) */
spi_xfer(slave, 16, dout, dout, SPI_XFER_BEGIN | SPI_XFER_END);
gpio_set_value(GPO_15, 1);
}
/*
* Read a value from a MAX6957AAX register.
*
* According to the MAX6957AAX datasheet, we should release the chip
* select halfway through the read sequence, when the actual register
* value is read; but the WORK_92105 hardware prevents the MAX6957AAX
* SPI OUT from reaching the LPC32XX SIP MISO if chip is not selected.
* so let's release the CS an hold it again while reading the result.
*/
static uint8_t max6957aax_read(uint8_t reg)
{
uint8_t dout[2], din[2];
/* send read command */
dout[0] = reg | 0x80; /* set bit 7 to indicate read */
dout[1] = 0;
gpio_set_value(GPO_15, 0);
/* do SPI read/write (passing din==dout is OK) */
spi_xfer(slave, 16, dout, dout, SPI_XFER_BEGIN | SPI_XFER_END);
/* latch read command */
gpio_set_value(GPO_15, 1);
/* read register -- din = noop on xmit, din[1] = reg on recv */
din[0] = 0;
din[1] = 0;
gpio_set_value(GPO_15, 0);
/* do SPI read/write (passing din==dout is OK) */
spi_xfer(slave, 16, din, din, SPI_XFER_BEGIN | SPI_XFER_END);
/* end of read. */
gpio_set_value(GPO_15, 1);
return din[1];
}
static void hd44780_instruction(unsigned long instruction)
{
max6957aax_write(MAX6957AAX_HD44780_RS, 0);
max6957aax_write(MAX6957AAX_HD44780_R_W, 0);
max6957aax_write(MAX6957AAX_HD44780_EN, 1);
max6957aax_write(MAX6957AAX_HD44780_DATA, instruction);
max6957aax_write(MAX6957AAX_HD44780_EN, 0);
/* HD44780 takes 37 us for most instructions, 1520 for clear */
if (instruction == HD44780_CLEAR_DISPLAY)
udelay(2000);
else
udelay(100);
}
static void hd44780_write_char(char c)
{
max6957aax_write(MAX6957AAX_HD44780_RS, 1);
max6957aax_write(MAX6957AAX_HD44780_R_W, 0);
max6957aax_write(MAX6957AAX_HD44780_EN, 1);
max6957aax_write(MAX6957AAX_HD44780_DATA, c);
max6957aax_write(MAX6957AAX_HD44780_EN, 0);
/* HD44780 takes 37 us to write to DDRAM or CGRAM */
udelay(100);
}
static void hd44780_write_str(char *s)
{
max6957aax_write(MAX6957AAX_HD44780_RS, 1);
max6957aax_write(MAX6957AAX_HD44780_R_W, 0);
while (*s) {
max6957aax_write(MAX6957AAX_HD44780_EN, 1);
max6957aax_write(MAX6957AAX_HD44780_DATA, *s);
max6957aax_write(MAX6957AAX_HD44780_EN, 0);
s++;
/* HD44780 takes 37 us to write to DDRAM or CGRAM */
udelay(100);
}
}
/*
* Existing user code might expect these custom characters to be
* recognized and displayed on the LCD
*/
static u8 char_gen_chars[] = {
/* #8, empty rectangle */
0x1F, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x1F,
/* #9, filled right arrow */
0x10, 0x18, 0x1C, 0x1E, 0x1C, 0x18, 0x10, 0x00,
/* #10, filled left arrow */
0x01, 0x03, 0x07, 0x0F, 0x07, 0x03, 0x01, 0x00,
/* #11, up and down arrow */
0x04, 0x0E, 0x1F, 0x00, 0x00, 0x1F, 0x0E, 0x04,
/* #12, plus/minus */
0x04, 0x04, 0x1F, 0x04, 0x04, 0x00, 0x1F, 0x00,
/* #13, fat exclamation mark */
0x06, 0x06, 0x06, 0x06, 0x00, 0x06, 0x06, 0x00,
/* #14, empty square */
0x00, 0x1F, 0x11, 0x11, 0x11, 0x1F, 0x00, 0x00,
/* #15, struck out square */
0x00, 0x1F, 0x19, 0x15, 0x13, 0x1F, 0x00, 0x00,
};
static void hd44780_init_char_gen(void)
{
int i;
hd44780_instruction(HD44780_SET_CGRAM_ADDR);
for (i = 0; i < sizeof(char_gen_chars); i++)
hd44780_write_char(char_gen_chars[i]);
hd44780_instruction(HD44780_SET_DDRAM_ADDR);
}
void work_92105_display_init(void)
{
int claim_err;
char *display_contrast_str;
uint8_t display_contrast = CONTRAST_DEFAULT;
uint8_t enable_backlight = 0x96;
slave = spi_setup_slave(0, 0, 500000, 0);
if (!slave) {
printf("Failed to set up SPI slave\n");
return;
}
claim_err = spi_claim_bus(slave);
if (claim_err)
debug("Failed to claim SPI bus: %d\n", claim_err);
/* enable backlight */
i2c_write(0x2c, 0x01, 1, &enable_backlight, 1);
/* set display contrast */
display_contrast_str = env_get("fwopt_dispcontrast");
if (display_contrast_str)
display_contrast = simple_strtoul(display_contrast_str,
NULL, 10);
i2c_write(0x2c, 0x00, 1, &display_contrast, 1);
/* request GPO_15 as an output initially set to 1 */
gpio_request(GPO_15, "MAX6957_nCS");
gpio_direction_output(GPO_15, 1);
/* enable MAX6957 portexpander */
max6957aax_write(MAX6957_CONF, 0x01);
/* configure pin 8 as input, pins 9..19 as outputs */
max6957aax_write(MAX6957_CONF_08_11, 0x56);
max6957aax_write(MAX6957_CONF_12_15, 0x55);
max6957aax_write(MAX6957_CONF_16_19, 0x55);
/* initialize HD44780 */
max6957aax_write(MAX6957AAX_HD44780_EN, 0);
hd44780_instruction(HD44780_FUNCTION_SET);
hd44780_instruction(HD44780_DISPLAY_ON_OFF_CONTROL);
hd44780_instruction(HD44780_ENTRY_MODE_SET);
/* write custom character glyphs */
hd44780_init_char_gen();
/* Show U-Boot version, date and time as a sign-of-life */
hd44780_instruction(HD44780_CLEAR_DISPLAY);
hd44780_instruction(HD44780_SET_DDRAM_ADDR | 0);
hd44780_write_str(U_BOOT_VERSION);
hd44780_instruction(HD44780_SET_DDRAM_ADDR | 64);
hd44780_write_str(U_BOOT_DATE);
hd44780_instruction(HD44780_SET_DDRAM_ADDR | 64 | 20);
hd44780_write_str(U_BOOT_TIME);
}
#ifdef CONFIG_CMD_MAX6957
static int do_max6957aax(cmd_tbl_t *cmdtp, int flag, int argc,
char *const argv[])
{
int reg, val;
if (argc != 3)
return CMD_RET_USAGE;
switch (argv[1][0]) {
case 'r':
case 'R':
reg = simple_strtoul(argv[2], NULL, 0);
val = max6957aax_read(reg);
printf("MAX6957 reg 0x%02x read 0x%02x\n", reg, val);
return 0;
default:
reg = simple_strtoul(argv[1], NULL, 0);
val = simple_strtoul(argv[2], NULL, 0);
max6957aax_write(reg, val);
printf("MAX6957 reg 0x%02x wrote 0x%02x\n", reg, val);
return 0;
}
return 1;
}
#ifdef CONFIG_SYS_LONGHELP
static char max6957aax_help_text[] =
"max6957aax - write or read display register:\n"
"\tmax6957aax R|r reg - read display register;\n"
"\tmax6957aax reg val - write display register.";
#endif
U_BOOT_CMD(
max6957aax, 6, 1, do_max6957aax,
"SPI MAX6957 display write/read",
max6957aax_help_text
);
#endif /* CONFIG_CMD_MAX6957 */
#ifdef CONFIG_CMD_HD44760
/*
* We need the HUSH parser because we need string arguments, and
* only HUSH can understand them.
*/
#if !defined(CONFIG_HUSH_PARSER)
#error CONFIG_CMD_HD44760 requires CONFIG_HUSH_PARSER
#endif
static int do_hd44780(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
{
char *cmd;
if (argc != 3)
return CMD_RET_USAGE;
cmd = argv[1];
if (strcasecmp(cmd, "cmd") == 0)
hd44780_instruction(simple_strtol(argv[2], NULL, 0));
else if (strcasecmp(cmd, "data") == 0)
hd44780_write_char(simple_strtol(argv[2], NULL, 0));
else if (strcasecmp(cmd, "str") == 0)
hd44780_write_str(argv[2]);
return 0;
}
#ifdef CONFIG_SYS_LONGHELP
static char hd44780_help_text[] =
"hd44780 - control LCD driver:\n"
"\thd44780 cmd <val> - send command <val> to driver;\n"
"\thd44780 data <val> - send data <val> to driver;\n"
"\thd44780 str \"<text>\" - send \"<text>\" to driver.";
#endif
U_BOOT_CMD(
hd44780, 6, 1, do_hd44780,
"HD44780 LCD driver control",
hd44780_help_text
);
#endif /* CONFIG_CMD_HD44760 */