377 lines
8.7 KiB
C
377 lines
8.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Console driver for LCD2S 4x20 character displays connected through i2c.
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* The display also has a SPI interface, but the driver does not support
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* this yet.
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*
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* This is a driver allowing you to use a LCD2S 4x20 from Modtronix
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* engineering as auxdisplay character device.
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*
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* (C) 2019 by Lemonage Software GmbH
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* Author: Lars Pöschel <poeschel@lemonage.de>
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* All rights reserved.
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*/
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#include <linux/kernel.h>
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#include <linux/mod_devicetable.h>
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#include <linux/module.h>
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#include <linux/property.h>
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#include <linux/slab.h>
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#include <linux/i2c.h>
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#include <linux/delay.h>
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#include "charlcd.h"
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#define LCD2S_CMD_CUR_MOVES_FWD 0x09
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#define LCD2S_CMD_CUR_BLINK_OFF 0x10
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#define LCD2S_CMD_CUR_UL_OFF 0x11
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#define LCD2S_CMD_DISPLAY_OFF 0x12
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#define LCD2S_CMD_CUR_BLINK_ON 0x18
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#define LCD2S_CMD_CUR_UL_ON 0x19
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#define LCD2S_CMD_DISPLAY_ON 0x1a
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#define LCD2S_CMD_BACKLIGHT_OFF 0x20
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#define LCD2S_CMD_BACKLIGHT_ON 0x28
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#define LCD2S_CMD_WRITE 0x80
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#define LCD2S_CMD_MOV_CUR_RIGHT 0x83
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#define LCD2S_CMD_MOV_CUR_LEFT 0x84
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#define LCD2S_CMD_SHIFT_RIGHT 0x85
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#define LCD2S_CMD_SHIFT_LEFT 0x86
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#define LCD2S_CMD_SHIFT_UP 0x87
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#define LCD2S_CMD_SHIFT_DOWN 0x88
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#define LCD2S_CMD_CUR_ADDR 0x89
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#define LCD2S_CMD_CUR_POS 0x8a
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#define LCD2S_CMD_CUR_RESET 0x8b
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#define LCD2S_CMD_CLEAR 0x8c
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#define LCD2S_CMD_DEF_CUSTOM_CHAR 0x92
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#define LCD2S_CMD_READ_STATUS 0xd0
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#define LCD2S_CHARACTER_SIZE 8
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#define LCD2S_STATUS_BUF_MASK 0x7f
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struct lcd2s_data {
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struct i2c_client *i2c;
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struct charlcd *charlcd;
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};
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static s32 lcd2s_wait_buf_free(const struct i2c_client *client, int count)
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{
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s32 status;
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status = i2c_smbus_read_byte_data(client, LCD2S_CMD_READ_STATUS);
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if (status < 0)
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return status;
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while ((status & LCD2S_STATUS_BUF_MASK) < count) {
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mdelay(1);
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status = i2c_smbus_read_byte_data(client,
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LCD2S_CMD_READ_STATUS);
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if (status < 0)
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return status;
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}
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return 0;
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}
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static int lcd2s_i2c_master_send(const struct i2c_client *client,
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const char *buf, int count)
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{
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s32 status;
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status = lcd2s_wait_buf_free(client, count);
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if (status < 0)
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return status;
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return i2c_master_send(client, buf, count);
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}
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static int lcd2s_i2c_smbus_write_byte(const struct i2c_client *client, u8 value)
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{
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s32 status;
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status = lcd2s_wait_buf_free(client, 1);
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if (status < 0)
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return status;
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return i2c_smbus_write_byte(client, value);
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}
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static int lcd2s_print(struct charlcd *lcd, int c)
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{
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struct lcd2s_data *lcd2s = lcd->drvdata;
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u8 buf[2] = { LCD2S_CMD_WRITE, c };
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lcd2s_i2c_master_send(lcd2s->i2c, buf, sizeof(buf));
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return 0;
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}
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static int lcd2s_gotoxy(struct charlcd *lcd, unsigned int x, unsigned int y)
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{
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struct lcd2s_data *lcd2s = lcd->drvdata;
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u8 buf[3] = { LCD2S_CMD_CUR_POS, y + 1, x + 1 };
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lcd2s_i2c_master_send(lcd2s->i2c, buf, sizeof(buf));
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return 0;
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}
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static int lcd2s_home(struct charlcd *lcd)
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{
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struct lcd2s_data *lcd2s = lcd->drvdata;
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lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_RESET);
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return 0;
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}
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static int lcd2s_init_display(struct charlcd *lcd)
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{
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struct lcd2s_data *lcd2s = lcd->drvdata;
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/* turn everything off, but display on */
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lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_DISPLAY_ON);
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lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_BACKLIGHT_OFF);
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lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_MOVES_FWD);
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lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_BLINK_OFF);
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lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_UL_OFF);
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lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CLEAR);
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return 0;
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}
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static int lcd2s_shift_cursor(struct charlcd *lcd, enum charlcd_shift_dir dir)
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{
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struct lcd2s_data *lcd2s = lcd->drvdata;
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if (dir == CHARLCD_SHIFT_LEFT)
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lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_MOV_CUR_LEFT);
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else
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lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_MOV_CUR_RIGHT);
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return 0;
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}
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static int lcd2s_shift_display(struct charlcd *lcd, enum charlcd_shift_dir dir)
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{
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struct lcd2s_data *lcd2s = lcd->drvdata;
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if (dir == CHARLCD_SHIFT_LEFT)
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lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_SHIFT_LEFT);
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else
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lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_SHIFT_RIGHT);
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return 0;
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}
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static void lcd2s_backlight(struct charlcd *lcd, enum charlcd_onoff on)
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{
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struct lcd2s_data *lcd2s = lcd->drvdata;
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if (on)
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lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_BACKLIGHT_ON);
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else
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lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_BACKLIGHT_OFF);
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}
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static int lcd2s_display(struct charlcd *lcd, enum charlcd_onoff on)
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{
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struct lcd2s_data *lcd2s = lcd->drvdata;
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if (on)
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lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_DISPLAY_ON);
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else
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lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_DISPLAY_OFF);
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return 0;
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}
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static int lcd2s_cursor(struct charlcd *lcd, enum charlcd_onoff on)
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{
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struct lcd2s_data *lcd2s = lcd->drvdata;
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if (on)
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lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_UL_ON);
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else
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lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_UL_OFF);
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return 0;
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}
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static int lcd2s_blink(struct charlcd *lcd, enum charlcd_onoff on)
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{
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struct lcd2s_data *lcd2s = lcd->drvdata;
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if (on)
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lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_BLINK_ON);
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else
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lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_BLINK_OFF);
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return 0;
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}
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static int lcd2s_fontsize(struct charlcd *lcd, enum charlcd_fontsize size)
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{
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return 0;
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}
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static int lcd2s_lines(struct charlcd *lcd, enum charlcd_lines lines)
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{
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return 0;
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}
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/*
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* Generator: LGcxxxxx...xx; must have <c> between '0' and '7',
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* representing the numerical ASCII code of the redefined character,
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* and <xx...xx> a sequence of 16 hex digits representing 8 bytes
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* for each character. Most LCDs will only use 5 lower bits of
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* the 7 first bytes.
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*/
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static int lcd2s_redefine_char(struct charlcd *lcd, char *esc)
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{
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struct lcd2s_data *lcd2s = lcd->drvdata;
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u8 buf[LCD2S_CHARACTER_SIZE + 2] = { LCD2S_CMD_DEF_CUSTOM_CHAR };
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u8 value;
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int shift, i;
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if (!strchr(esc, ';'))
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return 0;
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esc++;
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buf[1] = *(esc++) - '0';
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if (buf[1] > 7)
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return 1;
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i = 2;
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shift = 0;
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value = 0;
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while (*esc && i < LCD2S_CHARACTER_SIZE + 2) {
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int half;
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shift ^= 4;
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half = hex_to_bin(*esc++);
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if (half < 0)
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continue;
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value |= half << shift;
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if (shift == 0) {
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buf[i++] = value;
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value = 0;
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}
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}
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lcd2s_i2c_master_send(lcd2s->i2c, buf, sizeof(buf));
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return 1;
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}
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static int lcd2s_clear_display(struct charlcd *lcd)
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{
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struct lcd2s_data *lcd2s = lcd->drvdata;
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/* This implicitly sets cursor to first row and column */
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lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CLEAR);
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return 0;
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}
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static const struct charlcd_ops lcd2s_ops = {
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.print = lcd2s_print,
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.backlight = lcd2s_backlight,
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.gotoxy = lcd2s_gotoxy,
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.home = lcd2s_home,
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.clear_display = lcd2s_clear_display,
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.init_display = lcd2s_init_display,
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.shift_cursor = lcd2s_shift_cursor,
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.shift_display = lcd2s_shift_display,
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.display = lcd2s_display,
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.cursor = lcd2s_cursor,
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.blink = lcd2s_blink,
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.fontsize = lcd2s_fontsize,
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.lines = lcd2s_lines,
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.redefine_char = lcd2s_redefine_char,
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};
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static int lcd2s_i2c_probe(struct i2c_client *i2c)
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{
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struct charlcd *lcd;
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struct lcd2s_data *lcd2s;
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int err;
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if (!i2c_check_functionality(i2c->adapter,
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I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
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I2C_FUNC_SMBUS_WRITE_BLOCK_DATA))
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return -EIO;
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lcd2s = devm_kzalloc(&i2c->dev, sizeof(*lcd2s), GFP_KERNEL);
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if (!lcd2s)
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return -ENOMEM;
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/* Test, if the display is responding */
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err = lcd2s_i2c_smbus_write_byte(i2c, LCD2S_CMD_DISPLAY_OFF);
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if (err < 0)
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return err;
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lcd = charlcd_alloc();
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if (!lcd)
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return -ENOMEM;
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lcd->drvdata = lcd2s;
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lcd2s->i2c = i2c;
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lcd2s->charlcd = lcd;
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/* Required properties */
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err = device_property_read_u32(&i2c->dev, "display-height-chars",
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&lcd->height);
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if (err)
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goto fail1;
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err = device_property_read_u32(&i2c->dev, "display-width-chars",
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&lcd->width);
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if (err)
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goto fail1;
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lcd->ops = &lcd2s_ops;
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err = charlcd_register(lcd2s->charlcd);
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if (err)
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goto fail1;
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i2c_set_clientdata(i2c, lcd2s);
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return 0;
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fail1:
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charlcd_free(lcd2s->charlcd);
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return err;
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}
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static void lcd2s_i2c_remove(struct i2c_client *i2c)
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{
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struct lcd2s_data *lcd2s = i2c_get_clientdata(i2c);
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charlcd_unregister(lcd2s->charlcd);
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charlcd_free(lcd2s->charlcd);
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}
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static const struct i2c_device_id lcd2s_i2c_id[] = {
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{ "lcd2s", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, lcd2s_i2c_id);
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static const struct of_device_id lcd2s_of_table[] = {
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{ .compatible = "modtronix,lcd2s" },
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{ }
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};
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MODULE_DEVICE_TABLE(of, lcd2s_of_table);
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static struct i2c_driver lcd2s_i2c_driver = {
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.driver = {
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.name = "lcd2s",
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.of_match_table = lcd2s_of_table,
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},
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.probe = lcd2s_i2c_probe,
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.remove = lcd2s_i2c_remove,
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.id_table = lcd2s_i2c_id,
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};
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module_i2c_driver(lcd2s_i2c_driver);
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MODULE_DESCRIPTION("LCD2S character display driver");
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MODULE_AUTHOR("Lars Poeschel");
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MODULE_LICENSE("GPL");
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