xref: /linux/drivers/auxdisplay/lcd2s.c (revision cdd5b5a9761fd66d17586e4f4ba6588c70e640ea)
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 
lcd2s_wait_buf_free(const struct i2c_client * client,int count)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 
lcd2s_i2c_master_send(const struct i2c_client * client,const char * buf,int count)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 
lcd2s_i2c_smbus_write_byte(const struct i2c_client * client,u8 value)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, 1);
91 	if (status < 0)
92 		return status;
93 
94 	return i2c_smbus_write_byte(client, value);
95 }
96 
lcd2s_print(struct charlcd * lcd,int c)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(lcd2s->i2c, buf, sizeof(buf));
103 	return 0;
104 }
105 
lcd2s_gotoxy(struct charlcd * lcd,unsigned int x,unsigned int y)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(lcd2s->i2c, buf, sizeof(buf));
112 
113 	return 0;
114 }
115 
lcd2s_home(struct charlcd * lcd)116 static int lcd2s_home(struct charlcd *lcd)
117 {
118 	struct lcd2s_data *lcd2s = lcd->drvdata;
119 
120 	lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_RESET);
121 	return 0;
122 }
123 
lcd2s_init_display(struct charlcd * lcd)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(lcd2s->i2c, LCD2S_CMD_DISPLAY_ON);
130 	lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_BACKLIGHT_OFF);
131 	lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_MOVES_FWD);
132 	lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_BLINK_OFF);
133 	lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_UL_OFF);
134 	lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CLEAR);
135 
136 	return 0;
137 }
138 
lcd2s_shift_cursor(struct charlcd * lcd,enum charlcd_shift_dir dir)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(lcd2s->i2c, LCD2S_CMD_MOV_CUR_LEFT);
145 	else
146 		lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_MOV_CUR_RIGHT);
147 
148 	return 0;
149 }
150 
lcd2s_shift_display(struct charlcd * lcd,enum charlcd_shift_dir dir)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(lcd2s->i2c, LCD2S_CMD_SHIFT_LEFT);
157 	else
158 		lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_SHIFT_RIGHT);
159 
160 	return 0;
161 }
162 
lcd2s_backlight(struct charlcd * lcd,enum charlcd_onoff on)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(lcd2s->i2c, LCD2S_CMD_BACKLIGHT_ON);
169 	else
170 		lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_BACKLIGHT_OFF);
171 }
172 
lcd2s_display(struct charlcd * lcd,enum charlcd_onoff on)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(lcd2s->i2c, LCD2S_CMD_DISPLAY_ON);
179 	else
180 		lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_DISPLAY_OFF);
181 
182 	return 0;
183 }
184 
lcd2s_cursor(struct charlcd * lcd,enum charlcd_onoff on)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(lcd2s->i2c, LCD2S_CMD_CUR_UL_ON);
191 	else
192 		lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_UL_OFF);
193 
194 	return 0;
195 }
196 
lcd2s_blink(struct charlcd * lcd,enum charlcd_onoff on)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(lcd2s->i2c, LCD2S_CMD_CUR_BLINK_ON);
203 	else
204 		lcd2s_i2c_smbus_write_byte(lcd2s->i2c, LCD2S_CMD_CUR_BLINK_OFF);
205 
206 	return 0;
207 }
208 
lcd2s_fontsize(struct charlcd * lcd,enum charlcd_fontsize size)209 static int lcd2s_fontsize(struct charlcd *lcd, enum charlcd_fontsize size)
210 {
211 	return 0;
212 }
213 
lcd2s_lines(struct charlcd * lcd,enum charlcd_lines lines)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  */
lcd2s_redefine_char(struct charlcd * lcd,char * esc)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(*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(lcd2s->i2c, buf, sizeof(buf));
261 	return 1;
262 }
263 
lcd2s_clear_display(struct charlcd * lcd)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(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 
lcd2s_i2c_probe(struct i2c_client * i2c)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(i2c->adapter,
297 			I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
298 			I2C_FUNC_SMBUS_WRITE_BLOCK_DATA))
299 		return -EIO;
300 
301 	lcd2s = devm_kzalloc(&i2c->dev, 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(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(&i2c->dev, "display-height-chars",
320 			&lcd->height);
321 	if (err)
322 		goto fail1;
323 
324 	err = device_property_read_u32(&i2c->dev, "display-width-chars",
325 			&lcd->width);
326 	if (err)
327 		goto fail1;
328 
329 	lcd->ops = &lcd2s_ops;
330 
331 	err = charlcd_register(lcd2s->charlcd);
332 	if (err)
333 		goto fail1;
334 
335 	i2c_set_clientdata(i2c, lcd2s);
336 	return 0;
337 
338 fail1:
339 	charlcd_free(lcd2s->charlcd);
340 	return err;
341 }
342 
lcd2s_i2c_remove(struct i2c_client * i2c)343 static void lcd2s_i2c_remove(struct i2c_client *i2c)
344 {
345 	struct lcd2s_data *lcd2s = i2c_get_clientdata(i2c);
346 
347 	charlcd_unregister(lcd2s->charlcd);
348 	charlcd_free(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