diff options
Diffstat (limited to 'drivers/auxdisplay/charlcd.c')
| -rw-r--r-- | drivers/auxdisplay/charlcd.c | 119 |
1 files changed, 89 insertions, 30 deletions
diff --git a/drivers/auxdisplay/charlcd.c b/drivers/auxdisplay/charlcd.c index 642afd88870ba..8673fc2b9eb87 100644 --- a/drivers/auxdisplay/charlcd.c +++ b/drivers/auxdisplay/charlcd.c @@ -1,16 +1,13 @@ +// SPDX-License-Identifier: GPL-2.0+ /* * Character LCD driver for Linux * * Copyright (C) 2000-2008, Willy Tarreau <w@1wt.eu> * Copyright (C) 2016-2017 Glider bvba - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License - * as published by the Free Software Foundation; either version - * 2 of the License, or (at your option) any later version. */ #include <linux/atomic.h> +#include <linux/ctype.h> #include <linux/delay.h> #include <linux/fs.h> #include <linux/miscdevice.h> @@ -192,10 +189,11 @@ static void charlcd_print(struct charlcd *lcd, char c) c = lcd->char_conv[(unsigned char)c]; lcd->ops->write_data(lcd, c); priv->addr.x++; + + /* prevents the cursor from wrapping onto the next line */ + if (priv->addr.x == lcd->bwidth) + charlcd_gotoxy(lcd); } - /* prevents the cursor from wrapping onto the next line */ - if (priv->addr.x == lcd->bwidth) - charlcd_gotoxy(lcd); } static void charlcd_clear_fast(struct charlcd *lcd) @@ -293,6 +291,79 @@ static int charlcd_init_display(struct charlcd *lcd) } /* + * Parses an unsigned integer from a string, until a non-digit character + * is found. The empty string is not accepted. No overflow checks are done. + * + * Returns whether the parsing was successful. Only in that case + * the output parameters are written to. + * + * TODO: If the kernel adds an inplace version of kstrtoul(), this function + * could be easily replaced by that. + */ +static bool parse_n(const char *s, unsigned long *res, const char **next_s) +{ + if (!isdigit(*s)) + return false; + + *res = 0; + while (isdigit(*s)) { + *res = *res * 10 + (*s - '0'); + ++s; + } + + *next_s = s; + return true; +} + +/* + * Parses a movement command of the form "(.*);", where the group can be + * any number of subcommands of the form "(x|y)[0-9]+". + * + * Returns whether the command is valid. The position arguments are + * only written if the parsing was successful. + * + * For instance: + * - ";" returns (<original x>, <original y>). + * - "x1;" returns (1, <original y>). + * - "y2x1;" returns (1, 2). + * - "x12y34x56;" returns (56, 34). + * - "" fails. + * - "x" fails. + * - "x;" fails. + * - "x1" fails. + * - "xy12;" fails. + * - "x12yy12;" fails. + * - "xx" fails. + */ +static bool parse_xy(const char *s, unsigned long *x, unsigned long *y) +{ + unsigned long new_x = *x; + unsigned long new_y = *y; + + for (;;) { + if (!*s) + return false; + + if (*s == ';') + break; + + if (*s == 'x') { + if (!parse_n(s + 1, &new_x, &s)) + return false; + } else if (*s == 'y') { + if (!parse_n(s + 1, &new_y, &s)) + return false; + } else { + return false; + } + } + + *x = new_x; + *y = new_y; + return true; +} + +/* * These are the file operation function for user access to /dev/lcd * This function can also be called from inside the kernel, by * setting file and ppos to NULL. @@ -362,6 +433,7 @@ static inline int handle_lcd_special_code(struct charlcd *lcd) break; case 'N': /* Two Lines */ priv->flags |= LCD_FLAG_N; + processed = 1; break; case 'l': /* Shift Cursor Left */ if (priv->addr.x > 0) { @@ -441,9 +513,9 @@ static inline int handle_lcd_special_code(struct charlcd *lcd) shift ^= 4; if (*esc >= '0' && *esc <= '9') { value |= (*esc - '0') << shift; - } else if (*esc >= 'A' && *esc <= 'Z') { + } else if (*esc >= 'A' && *esc <= 'F') { value |= (*esc - 'A' + 10) << shift; - } else if (*esc >= 'a' && *esc <= 'z') { + } else if (*esc >= 'a' && *esc <= 'f') { value |= (*esc - 'a' + 10) << shift; } else { esc++; @@ -469,24 +541,11 @@ static inline int handle_lcd_special_code(struct charlcd *lcd) } case 'x': /* gotoxy : LxXXX[yYYY]; */ case 'y': /* gotoxy : LyYYY[xXXX]; */ - if (!strchr(esc, ';')) - break; - - while (*esc) { - if (*esc == 'x') { - esc++; - if (kstrtoul(esc, 10, &priv->addr.x) < 0) - break; - } else if (*esc == 'y') { - esc++; - if (kstrtoul(esc, 10, &priv->addr.y) < 0) - break; - } else { - break; - } - } + /* If the command is valid, move to the new address */ + if (parse_xy(esc, &priv->addr.x, &priv->addr.y)) + charlcd_gotoxy(lcd); - charlcd_gotoxy(lcd); + /* Regardless of its validity, mark as processed */ processed = 1; break; } @@ -527,7 +586,7 @@ static void charlcd_write_char(struct charlcd *lcd, char c) if ((c != '\n') && priv->esc_seq.len >= 0) { /* yes, let's add this char to the buffer */ priv->esc_seq.buf[priv->esc_seq.len++] = c; - priv->esc_seq.buf[priv->esc_seq.len] = 0; + priv->esc_seq.buf[priv->esc_seq.len] = '\0'; } else { /* aborts any previous escape sequence */ priv->esc_seq.len = -1; @@ -536,7 +595,7 @@ static void charlcd_write_char(struct charlcd *lcd, char c) case LCD_ESCAPE_CHAR: /* start of an escape sequence */ priv->esc_seq.len = 0; - priv->esc_seq.buf[priv->esc_seq.len] = 0; + priv->esc_seq.buf[priv->esc_seq.len] = '\0'; break; case '\b': /* go back one char and clear it */ @@ -555,7 +614,7 @@ static void charlcd_write_char(struct charlcd *lcd, char c) /* back one char again */ lcd->ops->write_cmd(lcd, LCD_CMD_SHIFT); break; - case '\014': + case '\f': /* quickly clear the display */ charlcd_clear_fast(lcd); break; |