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