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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * serial-generic.c4 * Copyright (c) by Daniel Kaehn <kaehndan@gmail.com5 * 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 Savolainen9 *10 * Generic serial MIDI driver using the serdev serial bus API for hardware interaction11 */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 133#define SERIAL_MODE_OUTPUT_OPEN 234#define SERIAL_MODE_INPUT_TRIGGERED 335#define SERIAL_MODE_OUTPUT_TRIGGERED 436 37#define SERIAL_TX_STATE_ACTIVE 138#define SERIAL_TX_STATE_WAKEUP 239 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 25665 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_wakeup119};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 else187 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 else234 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);375