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/mod_devicetable.h> |
16 | #include <linux/module.h> |
17 | #include <linux/property.h> |
18 | #include <linux/slab.h> |
19 | #include <linux/i2c.h> |
20 | #include <linux/delay.h> |
21 | |
22 | #include "charlcd.h" |
23 | |
24 | #define LCD2S_CMD_CUR_MOVES_FWD 0x09 |
25 | #define LCD2S_CMD_CUR_BLINK_OFF 0x10 |
26 | #define LCD2S_CMD_CUR_UL_OFF 0x11 |
27 | #define LCD2S_CMD_DISPLAY_OFF 0x12 |
28 | #define LCD2S_CMD_CUR_BLINK_ON 0x18 |
29 | #define LCD2S_CMD_CUR_UL_ON 0x19 |
30 | #define LCD2S_CMD_DISPLAY_ON 0x1a |
31 | #define LCD2S_CMD_BACKLIGHT_OFF 0x20 |
32 | #define LCD2S_CMD_BACKLIGHT_ON 0x28 |
33 | #define LCD2S_CMD_WRITE 0x80 |
34 | #define LCD2S_CMD_MOV_CUR_RIGHT 0x83 |
35 | #define LCD2S_CMD_MOV_CUR_LEFT 0x84 |
36 | #define LCD2S_CMD_SHIFT_RIGHT 0x85 |
37 | #define LCD2S_CMD_SHIFT_LEFT 0x86 |
38 | #define LCD2S_CMD_SHIFT_UP 0x87 |
39 | #define LCD2S_CMD_SHIFT_DOWN 0x88 |
40 | #define LCD2S_CMD_CUR_ADDR 0x89 |
41 | #define LCD2S_CMD_CUR_POS 0x8a |
42 | #define LCD2S_CMD_CUR_RESET 0x8b |
43 | #define LCD2S_CMD_CLEAR 0x8c |
44 | #define LCD2S_CMD_DEF_CUSTOM_CHAR 0x92 |
45 | #define LCD2S_CMD_READ_STATUS 0xd0 |
46 | |
47 | #define LCD2S_CHARACTER_SIZE 8 |
48 | |
49 | #define LCD2S_STATUS_BUF_MASK 0x7f |
50 | |
51 | struct lcd2s_data { |
52 | struct i2c_client *i2c; |
53 | struct charlcd *charlcd; |
54 | }; |
55 | |
56 | static s32 lcd2s_wait_buf_free(const struct i2c_client *client, int count) |
57 | { |
58 | s32 status; |
59 | |
60 | status = i2c_smbus_read_byte_data(client, LCD2S_CMD_READ_STATUS); |
61 | if (status < 0) |
62 | return status; |
63 | |
64 | while ((status & LCD2S_STATUS_BUF_MASK) < count) { |
65 | mdelay(1); |
66 | status = i2c_smbus_read_byte_data(client, |
67 | LCD2S_CMD_READ_STATUS); |
68 | if (status < 0) |
69 | return status; |
70 | } |
71 | return 0; |
72 | } |
73 | |
74 | static int lcd2s_i2c_master_send(const struct i2c_client *client, |
75 | const char *buf, int count) |
76 | { |
77 | s32 status; |
78 | |
79 | status = lcd2s_wait_buf_free(client, count); |
80 | if (status < 0) |
81 | return status; |
82 | |
83 | return i2c_master_send(client, buf, count); |
84 | } |
85 | |
86 | static int lcd2s_i2c_smbus_write_byte(const struct i2c_client *client, u8 value) |
87 | { |
88 | s32 status; |
89 | |
90 | status = lcd2s_wait_buf_free(client, count: 1); |
91 | if (status < 0) |
92 | return status; |
93 | |
94 | return i2c_smbus_write_byte(client, value); |
95 | } |
96 | |
97 | static int lcd2s_print(struct charlcd *lcd, int c) |
98 | { |
99 | struct lcd2s_data *lcd2s = lcd->drvdata; |
100 | u8 buf[2] = { LCD2S_CMD_WRITE, c }; |
101 | |
102 | lcd2s_i2c_master_send(client: lcd2s->i2c, buf, count: sizeof(buf)); |
103 | return 0; |
104 | } |
105 | |
106 | static int lcd2s_gotoxy(struct charlcd *lcd, unsigned int x, unsigned int y) |
107 | { |
108 | struct lcd2s_data *lcd2s = lcd->drvdata; |
109 | u8 buf[3] = { LCD2S_CMD_CUR_POS, y + 1, x + 1 }; |
110 | |
111 | lcd2s_i2c_master_send(client: lcd2s->i2c, buf, count: sizeof(buf)); |
112 | |
113 | return 0; |
114 | } |
115 | |
116 | static int lcd2s_home(struct charlcd *lcd) |
117 | { |
118 | struct lcd2s_data *lcd2s = lcd->drvdata; |
119 | |
120 | lcd2s_i2c_smbus_write_byte(client: lcd2s->i2c, LCD2S_CMD_CUR_RESET); |
121 | return 0; |
122 | } |
123 | |
124 | static int lcd2s_init_display(struct charlcd *lcd) |
125 | { |
126 | struct lcd2s_data *lcd2s = lcd->drvdata; |
127 | |
128 | /* turn everything off, but display on */ |
129 | lcd2s_i2c_smbus_write_byte(client: lcd2s->i2c, LCD2S_CMD_DISPLAY_ON); |
130 | lcd2s_i2c_smbus_write_byte(client: lcd2s->i2c, LCD2S_CMD_BACKLIGHT_OFF); |
131 | lcd2s_i2c_smbus_write_byte(client: lcd2s->i2c, LCD2S_CMD_CUR_MOVES_FWD); |
132 | lcd2s_i2c_smbus_write_byte(client: lcd2s->i2c, LCD2S_CMD_CUR_BLINK_OFF); |
133 | lcd2s_i2c_smbus_write_byte(client: lcd2s->i2c, LCD2S_CMD_CUR_UL_OFF); |
134 | lcd2s_i2c_smbus_write_byte(client: lcd2s->i2c, LCD2S_CMD_CLEAR); |
135 | |
136 | return 0; |
137 | } |
138 | |
139 | static int lcd2s_shift_cursor(struct charlcd *lcd, enum charlcd_shift_dir dir) |
140 | { |
141 | struct lcd2s_data *lcd2s = lcd->drvdata; |
142 | |
143 | if (dir == CHARLCD_SHIFT_LEFT) |
144 | lcd2s_i2c_smbus_write_byte(client: lcd2s->i2c, LCD2S_CMD_MOV_CUR_LEFT); |
145 | else |
146 | lcd2s_i2c_smbus_write_byte(client: lcd2s->i2c, LCD2S_CMD_MOV_CUR_RIGHT); |
147 | |
148 | return 0; |
149 | } |
150 | |
151 | static int lcd2s_shift_display(struct charlcd *lcd, enum charlcd_shift_dir dir) |
152 | { |
153 | struct lcd2s_data *lcd2s = lcd->drvdata; |
154 | |
155 | if (dir == CHARLCD_SHIFT_LEFT) |
156 | lcd2s_i2c_smbus_write_byte(client: lcd2s->i2c, LCD2S_CMD_SHIFT_LEFT); |
157 | else |
158 | lcd2s_i2c_smbus_write_byte(client: lcd2s->i2c, LCD2S_CMD_SHIFT_RIGHT); |
159 | |
160 | return 0; |
161 | } |
162 | |
163 | static void lcd2s_backlight(struct charlcd *lcd, enum charlcd_onoff on) |
164 | { |
165 | struct lcd2s_data *lcd2s = lcd->drvdata; |
166 | |
167 | if (on) |
168 | lcd2s_i2c_smbus_write_byte(client: lcd2s->i2c, LCD2S_CMD_BACKLIGHT_ON); |
169 | else |
170 | lcd2s_i2c_smbus_write_byte(client: lcd2s->i2c, LCD2S_CMD_BACKLIGHT_OFF); |
171 | } |
172 | |
173 | static int lcd2s_display(struct charlcd *lcd, enum charlcd_onoff on) |
174 | { |
175 | struct lcd2s_data *lcd2s = lcd->drvdata; |
176 | |
177 | if (on) |
178 | lcd2s_i2c_smbus_write_byte(client: lcd2s->i2c, LCD2S_CMD_DISPLAY_ON); |
179 | else |
180 | lcd2s_i2c_smbus_write_byte(client: lcd2s->i2c, LCD2S_CMD_DISPLAY_OFF); |
181 | |
182 | return 0; |
183 | } |
184 | |
185 | static int lcd2s_cursor(struct charlcd *lcd, enum charlcd_onoff on) |
186 | { |
187 | struct lcd2s_data *lcd2s = lcd->drvdata; |
188 | |
189 | if (on) |
190 | lcd2s_i2c_smbus_write_byte(client: lcd2s->i2c, LCD2S_CMD_CUR_UL_ON); |
191 | else |
192 | lcd2s_i2c_smbus_write_byte(client: lcd2s->i2c, LCD2S_CMD_CUR_UL_OFF); |
193 | |
194 | return 0; |
195 | } |
196 | |
197 | static int lcd2s_blink(struct charlcd *lcd, enum charlcd_onoff on) |
198 | { |
199 | struct lcd2s_data *lcd2s = lcd->drvdata; |
200 | |
201 | if (on) |
202 | lcd2s_i2c_smbus_write_byte(client: lcd2s->i2c, LCD2S_CMD_CUR_BLINK_ON); |
203 | else |
204 | lcd2s_i2c_smbus_write_byte(client: lcd2s->i2c, LCD2S_CMD_CUR_BLINK_OFF); |
205 | |
206 | return 0; |
207 | } |
208 | |
209 | static int lcd2s_fontsize(struct charlcd *lcd, enum charlcd_fontsize size) |
210 | { |
211 | return 0; |
212 | } |
213 | |
214 | static int lcd2s_lines(struct charlcd *lcd, enum charlcd_lines lines) |
215 | { |
216 | return 0; |
217 | } |
218 | |
219 | /* |
220 | * Generator: LGcxxxxx...xx; must have <c> between '0' and '7', |
221 | * representing the numerical ASCII code of the redefined character, |
222 | * and <xx...xx> a sequence of 16 hex digits representing 8 bytes |
223 | * for each character. Most LCDs will only use 5 lower bits of |
224 | * the 7 first bytes. |
225 | */ |
226 | static int lcd2s_redefine_char(struct charlcd *lcd, char *esc) |
227 | { |
228 | struct lcd2s_data *lcd2s = lcd->drvdata; |
229 | u8 buf[LCD2S_CHARACTER_SIZE + 2] = { LCD2S_CMD_DEF_CUSTOM_CHAR }; |
230 | u8 value; |
231 | int shift, i; |
232 | |
233 | if (!strchr(esc, ';')) |
234 | return 0; |
235 | |
236 | esc++; |
237 | |
238 | buf[1] = *(esc++) - '0'; |
239 | if (buf[1] > 7) |
240 | return 1; |
241 | |
242 | i = 2; |
243 | shift = 0; |
244 | value = 0; |
245 | while (*esc && i < LCD2S_CHARACTER_SIZE + 2) { |
246 | int half; |
247 | |
248 | shift ^= 4; |
249 | half = hex_to_bin(ch: *esc++); |
250 | if (half < 0) |
251 | continue; |
252 | |
253 | value |= half << shift; |
254 | if (shift == 0) { |
255 | buf[i++] = value; |
256 | value = 0; |
257 | } |
258 | } |
259 | |
260 | lcd2s_i2c_master_send(client: lcd2s->i2c, buf, count: sizeof(buf)); |
261 | return 1; |
262 | } |
263 | |
264 | static int lcd2s_clear_display(struct charlcd *lcd) |
265 | { |
266 | struct lcd2s_data *lcd2s = lcd->drvdata; |
267 | |
268 | /* This implicitly sets cursor to first row and column */ |
269 | lcd2s_i2c_smbus_write_byte(client: lcd2s->i2c, LCD2S_CMD_CLEAR); |
270 | return 0; |
271 | } |
272 | |
273 | static const struct charlcd_ops lcd2s_ops = { |
274 | .print = lcd2s_print, |
275 | .backlight = lcd2s_backlight, |
276 | .gotoxy = lcd2s_gotoxy, |
277 | .home = lcd2s_home, |
278 | .clear_display = lcd2s_clear_display, |
279 | .init_display = lcd2s_init_display, |
280 | .shift_cursor = lcd2s_shift_cursor, |
281 | .shift_display = lcd2s_shift_display, |
282 | .display = lcd2s_display, |
283 | .cursor = lcd2s_cursor, |
284 | .blink = lcd2s_blink, |
285 | .fontsize = lcd2s_fontsize, |
286 | .lines = lcd2s_lines, |
287 | .redefine_char = lcd2s_redefine_char, |
288 | }; |
289 | |
290 | static int lcd2s_i2c_probe(struct i2c_client *i2c) |
291 | { |
292 | struct charlcd *lcd; |
293 | struct lcd2s_data *lcd2s; |
294 | int err; |
295 | |
296 | if (!i2c_check_functionality(adap: i2c->adapter, |
297 | I2C_FUNC_SMBUS_WRITE_BYTE_DATA | |
298 | I2C_FUNC_SMBUS_WRITE_BLOCK_DATA)) |
299 | return -EIO; |
300 | |
301 | lcd2s = devm_kzalloc(dev: &i2c->dev, size: sizeof(*lcd2s), GFP_KERNEL); |
302 | if (!lcd2s) |
303 | return -ENOMEM; |
304 | |
305 | /* Test, if the display is responding */ |
306 | err = lcd2s_i2c_smbus_write_byte(client: i2c, LCD2S_CMD_DISPLAY_OFF); |
307 | if (err < 0) |
308 | return err; |
309 | |
310 | lcd = charlcd_alloc(); |
311 | if (!lcd) |
312 | return -ENOMEM; |
313 | |
314 | lcd->drvdata = lcd2s; |
315 | lcd2s->i2c = i2c; |
316 | lcd2s->charlcd = lcd; |
317 | |
318 | /* Required properties */ |
319 | err = device_property_read_u32(dev: &i2c->dev, propname: "display-height-chars" , |
320 | val: &lcd->height); |
321 | if (err) |
322 | goto fail1; |
323 | |
324 | err = device_property_read_u32(dev: &i2c->dev, propname: "display-width-chars" , |
325 | val: &lcd->width); |
326 | if (err) |
327 | goto fail1; |
328 | |
329 | lcd->ops = &lcd2s_ops; |
330 | |
331 | err = charlcd_register(lcd: lcd2s->charlcd); |
332 | if (err) |
333 | goto fail1; |
334 | |
335 | i2c_set_clientdata(client: i2c, data: lcd2s); |
336 | return 0; |
337 | |
338 | fail1: |
339 | charlcd_free(lcd: lcd2s->charlcd); |
340 | return err; |
341 | } |
342 | |
343 | static void lcd2s_i2c_remove(struct i2c_client *i2c) |
344 | { |
345 | struct lcd2s_data *lcd2s = i2c_get_clientdata(client: i2c); |
346 | |
347 | charlcd_unregister(lcd: lcd2s->charlcd); |
348 | charlcd_free(lcd: lcd2s->charlcd); |
349 | } |
350 | |
351 | static const struct i2c_device_id lcd2s_i2c_id[] = { |
352 | { "lcd2s" , 0 }, |
353 | { } |
354 | }; |
355 | MODULE_DEVICE_TABLE(i2c, lcd2s_i2c_id); |
356 | |
357 | static const struct of_device_id lcd2s_of_table[] = { |
358 | { .compatible = "modtronix,lcd2s" }, |
359 | { } |
360 | }; |
361 | MODULE_DEVICE_TABLE(of, lcd2s_of_table); |
362 | |
363 | static struct i2c_driver lcd2s_i2c_driver = { |
364 | .driver = { |
365 | .name = "lcd2s" , |
366 | .of_match_table = lcd2s_of_table, |
367 | }, |
368 | .probe = lcd2s_i2c_probe, |
369 | .remove = lcd2s_i2c_remove, |
370 | .id_table = lcd2s_i2c_id, |
371 | }; |
372 | module_i2c_driver(lcd2s_i2c_driver); |
373 | |
374 | MODULE_DESCRIPTION("LCD2S character display driver" ); |
375 | MODULE_AUTHOR("Lars Poeschel" ); |
376 | MODULE_LICENSE("GPL" ); |
377 | |