board/work-microwave/work_92105/work_92105_display.c - uboot-imx - Git at Google

 /*
  * 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.
  *
  * SPDX-License-Identifier:	GPL-2.0+
  */

 #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 = getenv("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_HD44780 */
	/*
	* 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.
	*
	* SPDX-License-Identifier: GPL-2.0+
	*/

	#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 = getenv("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_HD44780 */