tjh.dev
Linux kernel mirror (for testing)
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linux
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * console driver for LCD2S 4x20 character displays connected through i2c.
4 * The display also has a spi interface, but the driver does not support
5 * this yet.
6 *
7 * This is a driver allowing you to use a LCD2S 4x20 from modtronix
8 * engineering as auxdisplay character device.
9 *
10 * (C) 2019 by Lemonage Software GmbH
11 * Author: Lars Pöschel <poeschel@lemonage.de>
12 * All rights reserved.
13 */
14#include <linux/kernel.h>
15#include <linux/module.h>
16#include <linux/slab.h>
17#include <linux/i2c.h>
18#include <linux/delay.h>
19
20#include "charlcd.h"
21
22#define LCD2S_CMD_CUR_MOVES_FWD 0x09
23#define LCD2S_CMD_CUR_BLINK_OFF 0x10
24#define LCD2S_CMD_CUR_UL_OFF 0x11
25#define LCD2S_CMD_DISPLAY_OFF 0x12
26#define LCD2S_CMD_CUR_BLINK_ON 0x18
27#define LCD2S_CMD_CUR_UL_ON 0x19
28#define LCD2S_CMD_DISPLAY_ON 0x1a
29#define LCD2S_CMD_BACKLIGHT_OFF 0x20
30#define LCD2S_CMD_BACKLIGHT_ON 0x28
31#define LCD2S_CMD_WRITE 0x80
32#define LCD2S_CMD_MOV_CUR_RIGHT 0x83
33#define LCD2S_CMD_MOV_CUR_LEFT 0x84
34#define LCD2S_CMD_SHIFT_RIGHT 0x85
35#define LCD2S_CMD_SHIFT_LEFT 0x86
36#define LCD2S_CMD_SHIFT_UP 0x87
37#define LCD2S_CMD_SHIFT_DOWN 0x88
38#define LCD2S_CMD_CUR_ADDR 0x89
39#define LCD2S_CMD_CUR_POS 0x8a
40#define LCD2S_CMD_CUR_RESET 0x8b
41#define LCD2S_CMD_CLEAR 0x8c
42#define LCD2S_CMD_DEF_CUSTOM_CHAR 0x92
43#define LCD2S_CMD_READ_STATUS 0xd0
44
45#define LCD2S_CHARACTER_SIZE 8
46
47#define LCD2S_STATUS_BUF_MASK 0x7f
48
49struct lcd2s_data {
50 struct i2c_client *i2c;
51 struct charlcd *charlcd;
52};
53
54static s32 lcd2s_wait_buf_free(const struct i2c_client *client, int count)
55{
56 s32 status;
57
58 status = i2c_smbus_read_byte_data(client, LCD2S_CMD_READ_STATUS);
59 if (status < 0)
60 return status;
61
62 while ((status & LCD2S_STATUS_BUF_MASK) < count) {
63 mdelay(1);
64 status = i2c_smbus_read_byte_data(client,
65 LCD2S_CMD_READ_STATUS);
66 if (status < 0)
67 return status;
68 }
69 return 0;
70}
71
72static int lcd2s_i2c_master_send(const struct i2c_client *client,
73 const char *buf, int count)
74{
75 s32 status;
76
77 status = lcd2s_wait_buf_free(client, count);
78 if (status < 0)
79 return status;
80
81 return i2c_master_send(client, buf, count);
82}
83
84static int lcd2s_i2c_smbus_write_byte(const struct i2c_client *client, u8 value)
85{
86 s32 status;
87
88 status = lcd2s_wait_buf_free(client, 1);
89 if (status < 0)
90 return status;
91
92 return i2c_smbus_write_byte(client, value);
93}
94
95static int lcd2s_print(struct charlcd *lcd, int c)
96{
97 struct lcd2s_data *lcd2s = lcd->drvdata;
98 u8 buf[2] = { LCD2S_CMD_WRITE, c };
99
100 lcd2s_i2c_master_send(lcd2s->i2c, buf, sizeof(buf));
101 return 0;
102}
103
104static int lcd2s_gotoxy(struct charlcd *lcd, unsigned int x, unsigned int y)
105{
106 struct lcd2s_data *lcd2s = lcd->drvdata;
107 u8 buf[] = { LCD2S_CMD_CUR_POS, y + 1, x + 1};
108
109 lcd2s_i2c_master_send(lcd2s->i2c, buf, sizeof(buf));
110
111 return 0;
112}
113
114static int lcd2s_home(struct charlcd *lcd)
115{
116 struct lcd2s_data *lcd2s = lcd->drvdata;
117
118 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_RESET);
119 return 0;
120}
121
122static int lcd2s_init_display(struct charlcd *lcd)
123{
124 struct lcd2s_data *lcd2s = lcd->drvdata;
125
126 /* turn everything off, but display on */
127 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_DISPLAY_ON);
128 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_BACKLIGHT_OFF);
129 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_MOVES_FWD);
130 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_BLINK_OFF);
131 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_UL_OFF);
132 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CLEAR);
133
134 return 0;
135}
136
137static int lcd2s_shift_cursor(struct charlcd *lcd, enum charlcd_shift_dir dir)
138{
139 struct lcd2s_data *lcd2s = lcd->drvdata;
140
141 if (dir == CHARLCD_SHIFT_LEFT)
142 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_MOV_CUR_LEFT);
143 else
144 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_MOV_CUR_RIGHT);
145
146 return 0;
147}
148
149static int lcd2s_shift_display(struct charlcd *lcd, enum charlcd_shift_dir dir)
150{
151 struct lcd2s_data *lcd2s = lcd->drvdata;
152
153 if (dir == CHARLCD_SHIFT_LEFT)
154 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_SHIFT_LEFT);
155 else
156 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_SHIFT_RIGHT);
157
158 return 0;
159}
160
161static void lcd2s_backlight(struct charlcd *lcd, enum charlcd_onoff on)
162{
163 struct lcd2s_data *lcd2s = lcd->drvdata;
164
165 if (on)
166 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_BACKLIGHT_ON);
167 else
168 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_BACKLIGHT_OFF);
169}
170
171static int lcd2s_display(struct charlcd *lcd, enum charlcd_onoff on)
172{
173 struct lcd2s_data *lcd2s = lcd->drvdata;
174
175 if (on)
176 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_DISPLAY_ON);
177 else
178 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_DISPLAY_OFF);
179
180 return 0;
181}
182
183static int lcd2s_cursor(struct charlcd *lcd, enum charlcd_onoff on)
184{
185 struct lcd2s_data *lcd2s = lcd->drvdata;
186
187 if (on)
188 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_UL_ON);
189 else
190 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_UL_OFF);
191
192 return 0;
193}
194
195static int lcd2s_blink(struct charlcd *lcd, enum charlcd_onoff on)
196{
197 struct lcd2s_data *lcd2s = lcd->drvdata;
198
199 if (on)
200 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_BLINK_ON);
201 else
202 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_BLINK_OFF);
203
204 return 0;
205}
206
207static int lcd2s_fontsize(struct charlcd *lcd, enum charlcd_fontsize size)
208{
209 return 0;
210}
211
212static int lcd2s_lines(struct charlcd *lcd, enum charlcd_lines lines)
213{
214 return 0;
215}
216
217static int lcd2s_redefine_char(struct charlcd *lcd, char *esc)
218{
219 /* Generator : LGcxxxxx...xx; must have <c> between '0'
220 * and '7', representing the numerical ASCII code of the
221 * redefined character, and <xx...xx> a sequence of 16
222 * hex digits representing 8 bytes for each character.
223 * Most LCDs will only use 5 lower bits of the 7 first
224 * bytes.
225 */
226
227 struct lcd2s_data *lcd2s = lcd->drvdata;
228 u8 buf[LCD2S_CHARACTER_SIZE + 2] = { LCD2S_CMD_DEF_CUSTOM_CHAR };
229 u8 value;
230 int shift, i;
231
232 if (!strchr(esc, ';'))
233 return 0;
234
235 esc++;
236
237 buf[1] = *(esc++) - '0';
238 if (buf[1] > 7)
239 return 1;
240
241 i = 0;
242 shift = 0;
243 value = 0;
244 while (*esc && i < LCD2S_CHARACTER_SIZE + 2) {
245 int half;
246
247 shift ^= 4;
248 half = hex_to_bin(*esc++);
249 if (half < 0)
250 continue;
251
252 value |= half << shift;
253 if (shift == 0) {
254 buf[i++] = value;
255 value = 0;
256 }
257 }
258
259 lcd2s_i2c_master_send(lcd2s->i2c, buf, sizeof(buf));
260 return 1;
261}
262
263static int lcd2s_clear_display(struct charlcd *lcd)
264{
265 struct lcd2s_data *lcd2s = lcd->drvdata;
266
267 /* This implicitly sets cursor to first row and column */
268 lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CLEAR);
269 return 0;
270}
271
272static const struct charlcd_ops lcd2s_ops = {
273 .print = lcd2s_print,
274 .backlight = lcd2s_backlight,
275 .gotoxy = lcd2s_gotoxy,
276 .home = lcd2s_home,
277 .clear_display = lcd2s_clear_display,
278 .init_display = lcd2s_init_display,
279 .shift_cursor = lcd2s_shift_cursor,
280 .shift_display = lcd2s_shift_display,
281 .display = lcd2s_display,
282 .cursor = lcd2s_cursor,
283 .blink = lcd2s_blink,
284 .fontsize = lcd2s_fontsize,
285 .lines = lcd2s_lines,
286 .redefine_char = lcd2s_redefine_char,
287};
288
289static int lcd2s_i2c_probe(struct i2c_client *i2c,
290 const struct i2c_device_id *id)
291{
292 struct charlcd *lcd;
293 struct lcd2s_data *lcd2s;
294 int err;
295
296 if (!i2c_check_functionality(i2c->adapter,
297 I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
298 I2C_FUNC_SMBUS_WRITE_BLOCK_DATA))
299 return -EIO;
300
301 /* Test, if the display is responding */
302 err = lcd2s_i2c_smbus_write_byte(i2c, LCD2S_CMD_DISPLAY_OFF);
303 if (err < 0)
304 return err;
305
306 lcd = charlcd_alloc();
307 if (!lcd)
308 return -ENOMEM;
309
310 lcd2s = kzalloc(sizeof(struct lcd2s_data), GFP_KERNEL);
311 if (!lcd2s) {
312 err = -ENOMEM;
313 goto fail1;
314 }
315
316 lcd->drvdata = lcd2s;
317 lcd2s->i2c = i2c;
318 lcd2s->charlcd = lcd;
319
320 /* Required properties */
321 err = device_property_read_u32(&i2c->dev, "display-height-chars",
322 &lcd->height);
323 if (err)
324 goto fail2;
325
326 err = device_property_read_u32(&i2c->dev, "display-width-chars",
327 &lcd->width);
328 if (err)
329 goto fail2;
330
331 lcd->ops = &lcd2s_ops;
332
333 err = charlcd_register(lcd2s->charlcd);
334 if (err)
335 goto fail2;
336
337 i2c_set_clientdata(i2c, lcd2s);
338 return 0;
339
340fail2:
341 kfree(lcd2s);
342fail1:
343 kfree(lcd);
344 return err;
345}
346
347static int lcd2s_i2c_remove(struct i2c_client *i2c)
348{
349 struct lcd2s_data *lcd2s = i2c_get_clientdata(i2c);
350
351 charlcd_unregister(lcd2s->charlcd);
352 kfree(lcd2s->charlcd);
353 return 0;
354}
355
356static const struct i2c_device_id lcd2s_i2c_id[] = {
357 { "lcd2s", 0 },
358 { }
359};
360MODULE_DEVICE_TABLE(i2c, lcd2s_i2c_id);
361
362#ifdef CONFIG_OF
363static const struct of_device_id lcd2s_of_table[] = {
364 { .compatible = "modtronix,lcd2s" },
365 { }
366};
367MODULE_DEVICE_TABLE(of, lcd2s_of_table);
368#endif
369
370static struct i2c_driver lcd2s_i2c_driver = {
371 .driver = {
372 .name = "lcd2s",
373#ifdef CONFIG_OF
374 .of_match_table = of_match_ptr(lcd2s_of_table),
375#endif
376 },
377 .probe = lcd2s_i2c_probe,
378 .remove = lcd2s_i2c_remove,
379 .id_table = lcd2s_i2c_id,
380};
381
382static int __init lcd2s_modinit(void)
383{
384 int ret = 0;
385
386 ret = i2c_add_driver(&lcd2s_i2c_driver);
387 if (ret != 0)
388 pr_err("Failed to register lcd2s driver\n");
389
390 return ret;
391}
392module_init(lcd2s_modinit)
393
394static void __exit lcd2s_exit(void)
395{
396 i2c_del_driver(&lcd2s_i2c_driver);
397}
398module_exit(lcd2s_exit)
399
400MODULE_DESCRIPTION("LCD2S character display driver");
401MODULE_AUTHOR("Lars Poeschel");
402MODULE_LICENSE("GPL");