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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * serial-generic.c
4 * Copyright (c) by Daniel Kaehn <kaehndan@gmail.com
5 * Based on serial-u16550.c by Jaroslav Kysela <perex@perex.cz>,
6 * Isaku Yamahata <yamahata@private.email.ne.jp>,
7 * George Hansper <ghansper@apana.org.au>,
8 * Hannu Savolainen
9 *
10 * Generic serial MIDI driver using the serdev serial bus API for hardware interaction
11 */
12
13#include <linux/err.h>
14#include <linux/init.h>
15#include <linux/interrupt.h>
16#include <linux/io.h>
17#include <linux/ioport.h>
18#include <linux/module.h>
19#include <linux/of.h>
20#include <linux/serdev.h>
21#include <linux/serial_reg.h>
22#include <linux/slab.h>
23#include <linux/dev_printk.h>
24
25#include <sound/core.h>
26#include <sound/rawmidi.h>
27#include <sound/initval.h>
28
29MODULE_DESCRIPTION("Generic serial MIDI driver");
30MODULE_LICENSE("GPL");
31
32#define SERIAL_MODE_INPUT_OPEN 1
33#define SERIAL_MODE_OUTPUT_OPEN 2
34#define SERIAL_MODE_INPUT_TRIGGERED 3
35#define SERIAL_MODE_OUTPUT_TRIGGERED 4
36
37#define SERIAL_TX_STATE_ACTIVE 1
38#define SERIAL_TX_STATE_WAKEUP 2
39
40struct snd_serial_generic {
41 struct serdev_device *serdev;
42
43 struct snd_card *card;
44 struct snd_rawmidi *rmidi;
45 struct snd_rawmidi_substream *midi_output;
46 struct snd_rawmidi_substream *midi_input;
47
48 unsigned int baudrate;
49
50 unsigned long filemode; /* open status of file */
51 struct work_struct tx_work;
52 unsigned long tx_state;
53
54};
55
56static void snd_serial_generic_tx_wakeup(struct snd_serial_generic *drvdata)
57{
58 if (test_and_set_bit(SERIAL_TX_STATE_ACTIVE, &drvdata->tx_state))
59 set_bit(SERIAL_TX_STATE_WAKEUP, &drvdata->tx_state);
60
61 schedule_work(&drvdata->tx_work);
62}
63
64#define INTERNAL_BUF_SIZE 256
65
66static void snd_serial_generic_tx_work(struct work_struct *work)
67{
68 static char buf[INTERNAL_BUF_SIZE];
69 int num_bytes;
70 struct snd_serial_generic *drvdata = container_of(work, struct snd_serial_generic,
71 tx_work);
72 struct snd_rawmidi_substream *substream = drvdata->midi_output;
73
74 clear_bit(SERIAL_TX_STATE_WAKEUP, &drvdata->tx_state);
75
76 while (!snd_rawmidi_transmit_empty(substream)) {
77
78 if (!test_bit(SERIAL_MODE_OUTPUT_OPEN, &drvdata->filemode))
79 break;
80
81 num_bytes = snd_rawmidi_transmit_peek(substream, buf, INTERNAL_BUF_SIZE);
82 num_bytes = serdev_device_write_buf(drvdata->serdev, buf, num_bytes);
83
84 if (!num_bytes)
85 break;
86
87 snd_rawmidi_transmit_ack(substream, num_bytes);
88
89 if (!test_bit(SERIAL_TX_STATE_WAKEUP, &drvdata->tx_state))
90 break;
91 }
92
93 clear_bit(SERIAL_TX_STATE_ACTIVE, &drvdata->tx_state);
94}
95
96static void snd_serial_generic_write_wakeup(struct serdev_device *serdev)
97{
98 struct snd_serial_generic *drvdata = serdev_device_get_drvdata(serdev);
99
100 snd_serial_generic_tx_wakeup(drvdata);
101}
102
103static size_t snd_serial_generic_receive_buf(struct serdev_device *serdev,
104 const u8 *buf, size_t count)
105{
106 int ret;
107 struct snd_serial_generic *drvdata = serdev_device_get_drvdata(serdev);
108
109 if (!test_bit(SERIAL_MODE_INPUT_OPEN, &drvdata->filemode))
110 return 0;
111
112 ret = snd_rawmidi_receive(drvdata->midi_input, buf, count);
113 return ret < 0 ? 0 : ret;
114}
115
116static const struct serdev_device_ops snd_serial_generic_serdev_device_ops = {
117 .receive_buf = snd_serial_generic_receive_buf,
118 .write_wakeup = snd_serial_generic_write_wakeup
119};
120
121static int snd_serial_generic_ensure_serdev_open(struct snd_serial_generic *drvdata)
122{
123 int err;
124 unsigned int actual_baud;
125
126 if (drvdata->filemode)
127 return 0;
128
129 dev_dbg(drvdata->card->dev, "Opening serial port for card %s\n",
130 drvdata->card->shortname);
131 err = serdev_device_open(drvdata->serdev);
132 if (err < 0)
133 return err;
134
135 actual_baud = serdev_device_set_baudrate(drvdata->serdev,
136 drvdata->baudrate);
137 if (actual_baud != drvdata->baudrate) {
138 dev_warn(drvdata->card->dev, "requested %d baud for card %s but it was actually set to %d\n",
139 drvdata->baudrate, drvdata->card->shortname, actual_baud);
140 }
141
142 return 0;
143}
144
145static int snd_serial_generic_input_open(struct snd_rawmidi_substream *substream)
146{
147 int err;
148 struct snd_serial_generic *drvdata = substream->rmidi->card->private_data;
149
150 dev_dbg(drvdata->card->dev, "Opening input for card %s\n",
151 drvdata->card->shortname);
152
153 err = snd_serial_generic_ensure_serdev_open(drvdata);
154 if (err < 0)
155 return err;
156
157 set_bit(SERIAL_MODE_INPUT_OPEN, &drvdata->filemode);
158 drvdata->midi_input = substream;
159 return 0;
160}
161
162static int snd_serial_generic_input_close(struct snd_rawmidi_substream *substream)
163{
164 struct snd_serial_generic *drvdata = substream->rmidi->card->private_data;
165
166 dev_dbg(drvdata->card->dev, "Closing input for card %s\n",
167 drvdata->card->shortname);
168
169 clear_bit(SERIAL_MODE_INPUT_OPEN, &drvdata->filemode);
170 clear_bit(SERIAL_MODE_INPUT_TRIGGERED, &drvdata->filemode);
171
172 drvdata->midi_input = NULL;
173
174 if (!drvdata->filemode)
175 serdev_device_close(drvdata->serdev);
176 return 0;
177}
178
179static void snd_serial_generic_input_trigger(struct snd_rawmidi_substream *substream,
180 int up)
181{
182 struct snd_serial_generic *drvdata = substream->rmidi->card->private_data;
183
184 if (up)
185 set_bit(SERIAL_MODE_INPUT_TRIGGERED, &drvdata->filemode);
186 else
187 clear_bit(SERIAL_MODE_INPUT_TRIGGERED, &drvdata->filemode);
188}
189
190static int snd_serial_generic_output_open(struct snd_rawmidi_substream *substream)
191{
192 struct snd_serial_generic *drvdata = substream->rmidi->card->private_data;
193 int err;
194
195 dev_dbg(drvdata->card->dev, "Opening output for card %s\n",
196 drvdata->card->shortname);
197
198 err = snd_serial_generic_ensure_serdev_open(drvdata);
199 if (err < 0)
200 return err;
201
202 set_bit(SERIAL_MODE_OUTPUT_OPEN, &drvdata->filemode);
203
204 drvdata->midi_output = substream;
205 return 0;
206};
207
208static int snd_serial_generic_output_close(struct snd_rawmidi_substream *substream)
209{
210 struct snd_serial_generic *drvdata = substream->rmidi->card->private_data;
211
212 dev_dbg(drvdata->card->dev, "Closing output for card %s\n",
213 drvdata->card->shortname);
214
215 clear_bit(SERIAL_MODE_OUTPUT_OPEN, &drvdata->filemode);
216 clear_bit(SERIAL_MODE_OUTPUT_TRIGGERED, &drvdata->filemode);
217
218 if (!drvdata->filemode)
219 serdev_device_close(drvdata->serdev);
220
221 drvdata->midi_output = NULL;
222
223 return 0;
224};
225
226static void snd_serial_generic_output_trigger(struct snd_rawmidi_substream *substream,
227 int up)
228{
229 struct snd_serial_generic *drvdata = substream->rmidi->card->private_data;
230
231 if (up)
232 set_bit(SERIAL_MODE_OUTPUT_TRIGGERED, &drvdata->filemode);
233 else
234 clear_bit(SERIAL_MODE_OUTPUT_TRIGGERED, &drvdata->filemode);
235
236 if (up)
237 snd_serial_generic_tx_wakeup(drvdata);
238}
239
240static void snd_serial_generic_output_drain(struct snd_rawmidi_substream *substream)
241{
242 struct snd_serial_generic *drvdata = substream->rmidi->card->private_data;
243
244 /* Flush any pending characters */
245 serdev_device_write_flush(drvdata->serdev);
246 cancel_work_sync(&drvdata->tx_work);
247}
248
249static const struct snd_rawmidi_ops snd_serial_generic_output = {
250 .open = snd_serial_generic_output_open,
251 .close = snd_serial_generic_output_close,
252 .trigger = snd_serial_generic_output_trigger,
253 .drain = snd_serial_generic_output_drain,
254};
255
256static const struct snd_rawmidi_ops snd_serial_generic_input = {
257 .open = snd_serial_generic_input_open,
258 .close = snd_serial_generic_input_close,
259 .trigger = snd_serial_generic_input_trigger,
260};
261
262static void snd_serial_generic_parse_dt(struct serdev_device *serdev,
263 struct snd_serial_generic *drvdata)
264{
265 int err;
266
267 err = of_property_read_u32(serdev->dev.of_node, "current-speed",
268 &drvdata->baudrate);
269 if (err < 0) {
270 dev_dbg(drvdata->card->dev,
271 "MIDI device reading of current-speed DT param failed with error %d, using default of 38400\n",
272 err);
273 drvdata->baudrate = 38400;
274 }
275
276}
277
278static void snd_serial_generic_substreams(struct snd_rawmidi_str *stream, int dev_num)
279{
280 struct snd_rawmidi_substream *substream;
281
282 list_for_each_entry(substream, &stream->substreams, list) {
283 sprintf(substream->name, "Serial MIDI %d-%d", dev_num, substream->number);
284 }
285}
286
287static int snd_serial_generic_rmidi(struct snd_serial_generic *drvdata,
288 int outs, int ins, struct snd_rawmidi **rmidi)
289{
290 struct snd_rawmidi *rrawmidi;
291 int err;
292
293 err = snd_rawmidi_new(drvdata->card, drvdata->card->driver, 0,
294 outs, ins, &rrawmidi);
295
296 if (err < 0)
297 return err;
298
299 snd_rawmidi_set_ops(rrawmidi, SNDRV_RAWMIDI_STREAM_INPUT,
300 &snd_serial_generic_input);
301 snd_rawmidi_set_ops(rrawmidi, SNDRV_RAWMIDI_STREAM_OUTPUT,
302 &snd_serial_generic_output);
303 strcpy(rrawmidi->name, drvdata->card->shortname);
304
305 snd_serial_generic_substreams(&rrawmidi->streams[SNDRV_RAWMIDI_STREAM_OUTPUT],
306 drvdata->serdev->ctrl->nr);
307 snd_serial_generic_substreams(&rrawmidi->streams[SNDRV_RAWMIDI_STREAM_INPUT],
308 drvdata->serdev->ctrl->nr);
309
310 rrawmidi->info_flags = SNDRV_RAWMIDI_INFO_OUTPUT |
311 SNDRV_RAWMIDI_INFO_INPUT |
312 SNDRV_RAWMIDI_INFO_DUPLEX;
313
314 if (rmidi)
315 *rmidi = rrawmidi;
316 return 0;
317}
318
319static int snd_serial_generic_probe(struct serdev_device *serdev)
320{
321 struct snd_card *card;
322 struct snd_serial_generic *drvdata;
323 int err;
324
325 err = snd_devm_card_new(&serdev->dev, SNDRV_DEFAULT_IDX1,
326 SNDRV_DEFAULT_STR1, THIS_MODULE,
327 sizeof(struct snd_serial_generic), &card);
328
329 if (err < 0)
330 return err;
331
332 strcpy(card->driver, "SerialMIDI");
333 sprintf(card->shortname, "SerialMIDI-%d", serdev->ctrl->nr);
334 sprintf(card->longname, "Serial MIDI device at serial%d", serdev->ctrl->nr);
335
336 drvdata = card->private_data;
337
338 drvdata->serdev = serdev;
339 drvdata->card = card;
340
341 snd_serial_generic_parse_dt(serdev, drvdata);
342
343 INIT_WORK(&drvdata->tx_work, snd_serial_generic_tx_work);
344
345 err = snd_serial_generic_rmidi(drvdata, 1, 1, &drvdata->rmidi);
346 if (err < 0)
347 return err;
348
349 serdev_device_set_client_ops(serdev, &snd_serial_generic_serdev_device_ops);
350 serdev_device_set_drvdata(drvdata->serdev, drvdata);
351
352 err = snd_card_register(card);
353 if (err < 0)
354 return err;
355
356 return 0;
357}
358
359static const struct of_device_id snd_serial_generic_dt_ids[] = {
360 { .compatible = "serial-midi" },
361 {},
362};
363
364MODULE_DEVICE_TABLE(of, snd_serial_generic_dt_ids);
365
366static struct serdev_device_driver snd_serial_generic_driver = {
367 .driver = {
368 .name = "snd-serial-generic",
369 .of_match_table = snd_serial_generic_dt_ids,
370 },
371 .probe = snd_serial_generic_probe,
372};
373
374module_serdev_device_driver(snd_serial_generic_driver);