1 /*
2  * Driver for Microchip MRF24J40 802.15.4 Wireless-PAN Networking controller
3  *
4  * Copyright (C) 2012 Alan Ott <alan@signal11.us>
5  *                    Signal 11 Software
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 2 of the License, or
10  * (at your option) any later version.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20  */
21 
22 #include <linux/spi/spi.h>
23 #include <linux/interrupt.h>
24 #include <linux/module.h>
25 #include <linux/pinctrl/consumer.h>
26 #include <net/wpan-phy.h>
27 #include <net/mac802154.h>
28 #include <net/ieee802154.h>
29 
30 /* MRF24J40 Short Address Registers */
31 #define REG_RXMCR    0x00  /* Receive MAC control */
32 #define REG_PANIDL   0x01  /* PAN ID (low) */
33 #define REG_PANIDH   0x02  /* PAN ID (high) */
34 #define REG_SADRL    0x03  /* Short address (low) */
35 #define REG_SADRH    0x04  /* Short address (high) */
36 #define REG_EADR0    0x05  /* Long address (low) (high is EADR7) */
37 #define REG_TXMCR    0x11  /* Transmit MAC control */
38 #define REG_PACON0   0x16  /* Power Amplifier Control */
39 #define REG_PACON1   0x17  /* Power Amplifier Control */
40 #define REG_PACON2   0x18  /* Power Amplifier Control */
41 #define REG_TXNCON   0x1B  /* Transmit Normal FIFO Control */
42 #define REG_TXSTAT   0x24  /* TX MAC Status Register */
43 #define REG_SOFTRST  0x2A  /* Soft Reset */
44 #define REG_TXSTBL   0x2E  /* TX Stabilization */
45 #define REG_INTSTAT  0x31  /* Interrupt Status */
46 #define REG_INTCON   0x32  /* Interrupt Control */
47 #define REG_RFCTL    0x36  /* RF Control Mode Register */
48 #define REG_BBREG1   0x39  /* Baseband Registers */
49 #define REG_BBREG2   0x3A  /* */
50 #define REG_BBREG6   0x3E  /* */
51 #define REG_CCAEDTH  0x3F  /* Energy Detection Threshold */
52 
53 /* MRF24J40 Long Address Registers */
54 #define REG_RFCON0     0x200  /* RF Control Registers */
55 #define REG_RFCON1     0x201
56 #define REG_RFCON2     0x202
57 #define REG_RFCON3     0x203
58 #define REG_RFCON5     0x205
59 #define REG_RFCON6     0x206
60 #define REG_RFCON7     0x207
61 #define REG_RFCON8     0x208
62 #define REG_RSSI       0x210
63 #define REG_SLPCON0    0x211  /* Sleep Clock Control Registers */
64 #define REG_SLPCON1    0x220
65 #define REG_WAKETIMEL  0x222  /* Wake-up Time Match Value Low */
66 #define REG_WAKETIMEH  0x223  /* Wake-up Time Match Value High */
67 #define REG_RX_FIFO    0x300  /* Receive FIFO */
68 
69 /* Device configuration: Only channels 11-26 on page 0 are supported. */
70 #define MRF24J40_CHAN_MIN 11
71 #define MRF24J40_CHAN_MAX 26
72 #define CHANNEL_MASK (((u32)1 << (MRF24J40_CHAN_MAX + 1)) \
73 		      - ((u32)1 << MRF24J40_CHAN_MIN))
74 
75 #define TX_FIFO_SIZE 128 /* From datasheet */
76 #define RX_FIFO_SIZE 144 /* From datasheet */
77 #define SET_CHANNEL_DELAY_US 192 /* From datasheet */
78 
79 /* Device Private Data */
80 struct mrf24j40 {
81 	struct spi_device *spi;
82 	struct ieee802154_dev *dev;
83 
84 	struct mutex buffer_mutex; /* only used to protect buf */
85 	struct completion tx_complete;
86 	struct work_struct irqwork;
87 	u8 *buf; /* 3 bytes. Used for SPI single-register transfers. */
88 };
89 
90 /* Read/Write SPI Commands for Short and Long Address registers. */
91 #define MRF24J40_READSHORT(reg) ((reg) << 1)
92 #define MRF24J40_WRITESHORT(reg) ((reg) << 1 | 1)
93 #define MRF24J40_READLONG(reg) (1 << 15 | (reg) << 5)
94 #define MRF24J40_WRITELONG(reg) (1 << 15 | (reg) << 5 | 1 << 4)
95 
96 /* The datasheet indicates the theoretical maximum for SCK to be 10MHz */
97 #define MAX_SPI_SPEED_HZ 10000000
98 
99 #define printdev(X) (&X->spi->dev)
100 
101 static int write_short_reg(struct mrf24j40 *devrec, u8 reg, u8 value)
102 {
103 	int ret;
104 	struct spi_message msg;
105 	struct spi_transfer xfer = {
106 		.len = 2,
107 		.tx_buf = devrec->buf,
108 		.rx_buf = devrec->buf,
109 	};
110 
111 	spi_message_init(&msg);
112 	spi_message_add_tail(&xfer, &msg);
113 
114 	mutex_lock(&devrec->buffer_mutex);
115 	devrec->buf[0] = MRF24J40_WRITESHORT(reg);
116 	devrec->buf[1] = value;
117 
118 	ret = spi_sync(devrec->spi, &msg);
119 	if (ret)
120 		dev_err(printdev(devrec),
121 			"SPI write Failed for short register 0x%hhx\n", reg);
122 
123 	mutex_unlock(&devrec->buffer_mutex);
124 	return ret;
125 }
126 
127 static int read_short_reg(struct mrf24j40 *devrec, u8 reg, u8 *val)
128 {
129 	int ret = -1;
130 	struct spi_message msg;
131 	struct spi_transfer xfer = {
132 		.len = 2,
133 		.tx_buf = devrec->buf,
134 		.rx_buf = devrec->buf,
135 	};
136 
137 	spi_message_init(&msg);
138 	spi_message_add_tail(&xfer, &msg);
139 
140 	mutex_lock(&devrec->buffer_mutex);
141 	devrec->buf[0] = MRF24J40_READSHORT(reg);
142 	devrec->buf[1] = 0;
143 
144 	ret = spi_sync(devrec->spi, &msg);
145 	if (ret)
146 		dev_err(printdev(devrec),
147 			"SPI read Failed for short register 0x%hhx\n", reg);
148 	else
149 		*val = devrec->buf[1];
150 
151 	mutex_unlock(&devrec->buffer_mutex);
152 	return ret;
153 }
154 
155 static int read_long_reg(struct mrf24j40 *devrec, u16 reg, u8 *value)
156 {
157 	int ret;
158 	u16 cmd;
159 	struct spi_message msg;
160 	struct spi_transfer xfer = {
161 		.len = 3,
162 		.tx_buf = devrec->buf,
163 		.rx_buf = devrec->buf,
164 	};
165 
166 	spi_message_init(&msg);
167 	spi_message_add_tail(&xfer, &msg);
168 
169 	cmd = MRF24J40_READLONG(reg);
170 	mutex_lock(&devrec->buffer_mutex);
171 	devrec->buf[0] = cmd >> 8 & 0xff;
172 	devrec->buf[1] = cmd & 0xff;
173 	devrec->buf[2] = 0;
174 
175 	ret = spi_sync(devrec->spi, &msg);
176 	if (ret)
177 		dev_err(printdev(devrec),
178 			"SPI read Failed for long register 0x%hx\n", reg);
179 	else
180 		*value = devrec->buf[2];
181 
182 	mutex_unlock(&devrec->buffer_mutex);
183 	return ret;
184 }
185 
186 static int write_long_reg(struct mrf24j40 *devrec, u16 reg, u8 val)
187 {
188 	int ret;
189 	u16 cmd;
190 	struct spi_message msg;
191 	struct spi_transfer xfer = {
192 		.len = 3,
193 		.tx_buf = devrec->buf,
194 		.rx_buf = devrec->buf,
195 	};
196 
197 	spi_message_init(&msg);
198 	spi_message_add_tail(&xfer, &msg);
199 
200 	cmd = MRF24J40_WRITELONG(reg);
201 	mutex_lock(&devrec->buffer_mutex);
202 	devrec->buf[0] = cmd >> 8 & 0xff;
203 	devrec->buf[1] = cmd & 0xff;
204 	devrec->buf[2] = val;
205 
206 	ret = spi_sync(devrec->spi, &msg);
207 	if (ret)
208 		dev_err(printdev(devrec),
209 			"SPI write Failed for long register 0x%hx\n", reg);
210 
211 	mutex_unlock(&devrec->buffer_mutex);
212 	return ret;
213 }
214 
215 /* This function relies on an undocumented write method. Once a write command
216    and address is set, as many bytes of data as desired can be clocked into
217    the device. The datasheet only shows setting one byte at a time. */
218 static int write_tx_buf(struct mrf24j40 *devrec, u16 reg,
219 			const u8 *data, size_t length)
220 {
221 	int ret;
222 	u16 cmd;
223 	u8 lengths[2];
224 	struct spi_message msg;
225 	struct spi_transfer addr_xfer = {
226 		.len = 2,
227 		.tx_buf = devrec->buf,
228 	};
229 	struct spi_transfer lengths_xfer = {
230 		.len = 2,
231 		.tx_buf = &lengths, /* TODO: Is DMA really required for SPI? */
232 	};
233 	struct spi_transfer data_xfer = {
234 		.len = length,
235 		.tx_buf = data,
236 	};
237 
238 	/* Range check the length. 2 bytes are used for the length fields.*/
239 	if (length > TX_FIFO_SIZE-2) {
240 		dev_err(printdev(devrec), "write_tx_buf() was passed too large a buffer. Performing short write.\n");
241 		length = TX_FIFO_SIZE-2;
242 	}
243 
244 	spi_message_init(&msg);
245 	spi_message_add_tail(&addr_xfer, &msg);
246 	spi_message_add_tail(&lengths_xfer, &msg);
247 	spi_message_add_tail(&data_xfer, &msg);
248 
249 	cmd = MRF24J40_WRITELONG(reg);
250 	mutex_lock(&devrec->buffer_mutex);
251 	devrec->buf[0] = cmd >> 8 & 0xff;
252 	devrec->buf[1] = cmd & 0xff;
253 	lengths[0] = 0x0; /* Header Length. Set to 0 for now. TODO */
254 	lengths[1] = length; /* Total length */
255 
256 	ret = spi_sync(devrec->spi, &msg);
257 	if (ret)
258 		dev_err(printdev(devrec), "SPI write Failed for TX buf\n");
259 
260 	mutex_unlock(&devrec->buffer_mutex);
261 	return ret;
262 }
263 
264 static int mrf24j40_read_rx_buf(struct mrf24j40 *devrec,
265 				u8 *data, u8 *len, u8 *lqi)
266 {
267 	u8 rx_len;
268 	u8 addr[2];
269 	u8 lqi_rssi[2];
270 	u16 cmd;
271 	int ret;
272 	struct spi_message msg;
273 	struct spi_transfer addr_xfer = {
274 		.len = 2,
275 		.tx_buf = &addr,
276 	};
277 	struct spi_transfer data_xfer = {
278 		.len = 0x0, /* set below */
279 		.rx_buf = data,
280 	};
281 	struct spi_transfer status_xfer = {
282 		.len = 2,
283 		.rx_buf = &lqi_rssi,
284 	};
285 
286 	/* Get the length of the data in the RX FIFO. The length in this
287 	 * register exclues the 1-byte length field at the beginning. */
288 	ret = read_long_reg(devrec, REG_RX_FIFO, &rx_len);
289 	if (ret)
290 		goto out;
291 
292 	/* Range check the RX FIFO length, accounting for the one-byte
293 	 * length field at the begining. */
294 	if (rx_len > RX_FIFO_SIZE-1) {
295 		dev_err(printdev(devrec), "Invalid length read from device. Performing short read.\n");
296 		rx_len = RX_FIFO_SIZE-1;
297 	}
298 
299 	if (rx_len > *len) {
300 		/* Passed in buffer wasn't big enough. Should never happen. */
301 		dev_err(printdev(devrec), "Buffer not big enough. Performing short read\n");
302 		rx_len = *len;
303 	}
304 
305 	/* Set up the commands to read the data. */
306 	cmd = MRF24J40_READLONG(REG_RX_FIFO+1);
307 	addr[0] = cmd >> 8 & 0xff;
308 	addr[1] = cmd & 0xff;
309 	data_xfer.len = rx_len;
310 
311 	spi_message_init(&msg);
312 	spi_message_add_tail(&addr_xfer, &msg);
313 	spi_message_add_tail(&data_xfer, &msg);
314 	spi_message_add_tail(&status_xfer, &msg);
315 
316 	ret = spi_sync(devrec->spi, &msg);
317 	if (ret) {
318 		dev_err(printdev(devrec), "SPI RX Buffer Read Failed.\n");
319 		goto out;
320 	}
321 
322 	*lqi = lqi_rssi[0];
323 	*len = rx_len;
324 
325 #ifdef DEBUG
326 	print_hex_dump(KERN_DEBUG, "mrf24j40 rx: ",
327 		DUMP_PREFIX_OFFSET, 16, 1, data, *len, 0);
328 	printk(KERN_DEBUG "mrf24j40 rx: lqi: %02hhx rssi: %02hhx\n",
329 		lqi_rssi[0], lqi_rssi[1]);
330 #endif
331 
332 out:
333 	return ret;
334 }
335 
336 static int mrf24j40_tx(struct ieee802154_dev *dev, struct sk_buff *skb)
337 {
338 	struct mrf24j40 *devrec = dev->priv;
339 	u8 val;
340 	int ret = 0;
341 
342 	dev_dbg(printdev(devrec), "tx packet of %d bytes\n", skb->len);
343 
344 	ret = write_tx_buf(devrec, 0x000, skb->data, skb->len);
345 	if (ret)
346 		goto err;
347 
348 	/* Set TXNTRIG bit of TXNCON to send packet */
349 	ret = read_short_reg(devrec, REG_TXNCON, &val);
350 	if (ret)
351 		goto err;
352 	val |= 0x1;
353 	/* Set TXNACKREQ if the ACK bit is set in the packet. */
354 	if (skb->data[0] & IEEE802154_FC_ACK_REQ)
355 		val |= 0x4;
356 	write_short_reg(devrec, REG_TXNCON, val);
357 
358 	INIT_COMPLETION(devrec->tx_complete);
359 
360 	/* Wait for the device to send the TX complete interrupt. */
361 	ret = wait_for_completion_interruptible_timeout(
362 						&devrec->tx_complete,
363 						5 * HZ);
364 	if (ret == -ERESTARTSYS)
365 		goto err;
366 	if (ret == 0) {
367 		dev_warn(printdev(devrec), "Timeout waiting for TX interrupt\n");
368 		ret = -ETIMEDOUT;
369 		goto err;
370 	}
371 
372 	/* Check for send error from the device. */
373 	ret = read_short_reg(devrec, REG_TXSTAT, &val);
374 	if (ret)
375 		goto err;
376 	if (val & 0x1) {
377 		dev_dbg(printdev(devrec), "Error Sending. Retry count exceeded\n");
378 		ret = -ECOMM; /* TODO: Better error code ? */
379 	} else
380 		dev_dbg(printdev(devrec), "Packet Sent\n");
381 
382 err:
383 
384 	return ret;
385 }
386 
387 static int mrf24j40_ed(struct ieee802154_dev *dev, u8 *level)
388 {
389 	/* TODO: */
390 	printk(KERN_WARNING "mrf24j40: ed not implemented\n");
391 	*level = 0;
392 	return 0;
393 }
394 
395 static int mrf24j40_start(struct ieee802154_dev *dev)
396 {
397 	struct mrf24j40 *devrec = dev->priv;
398 	u8 val;
399 	int ret;
400 
401 	dev_dbg(printdev(devrec), "start\n");
402 
403 	ret = read_short_reg(devrec, REG_INTCON, &val);
404 	if (ret)
405 		return ret;
406 	val &= ~(0x1|0x8); /* Clear TXNIE and RXIE. Enable interrupts */
407 	write_short_reg(devrec, REG_INTCON, val);
408 
409 	return 0;
410 }
411 
412 static void mrf24j40_stop(struct ieee802154_dev *dev)
413 {
414 	struct mrf24j40 *devrec = dev->priv;
415 	u8 val;
416 	int ret;
417 	dev_dbg(printdev(devrec), "stop\n");
418 
419 	ret = read_short_reg(devrec, REG_INTCON, &val);
420 	if (ret)
421 		return;
422 	val |= 0x1|0x8; /* Set TXNIE and RXIE. Disable Interrupts */
423 	write_short_reg(devrec, REG_INTCON, val);
424 
425 	return;
426 }
427 
428 static int mrf24j40_set_channel(struct ieee802154_dev *dev,
429 				int page, int channel)
430 {
431 	struct mrf24j40 *devrec = dev->priv;
432 	u8 val;
433 	int ret;
434 
435 	dev_dbg(printdev(devrec), "Set Channel %d\n", channel);
436 
437 	WARN_ON(page != 0);
438 	WARN_ON(channel < MRF24J40_CHAN_MIN);
439 	WARN_ON(channel > MRF24J40_CHAN_MAX);
440 
441 	/* Set Channel TODO */
442 	val = (channel-11) << 4 | 0x03;
443 	write_long_reg(devrec, REG_RFCON0, val);
444 
445 	/* RF Reset */
446 	ret = read_short_reg(devrec, REG_RFCTL, &val);
447 	if (ret)
448 		return ret;
449 	val |= 0x04;
450 	write_short_reg(devrec, REG_RFCTL, val);
451 	val &= ~0x04;
452 	write_short_reg(devrec, REG_RFCTL, val);
453 
454 	udelay(SET_CHANNEL_DELAY_US); /* per datasheet */
455 
456 	return 0;
457 }
458 
459 static int mrf24j40_filter(struct ieee802154_dev *dev,
460 			   struct ieee802154_hw_addr_filt *filt,
461 			   unsigned long changed)
462 {
463 	struct mrf24j40 *devrec = dev->priv;
464 
465 	dev_dbg(printdev(devrec), "filter\n");
466 
467 	if (changed & IEEE802515_AFILT_SADDR_CHANGED) {
468 		/* Short Addr */
469 		u8 addrh, addrl;
470 		addrh = filt->short_addr >> 8 & 0xff;
471 		addrl = filt->short_addr & 0xff;
472 
473 		write_short_reg(devrec, REG_SADRH, addrh);
474 		write_short_reg(devrec, REG_SADRL, addrl);
475 		dev_dbg(printdev(devrec),
476 			"Set short addr to %04hx\n", filt->short_addr);
477 	}
478 
479 	if (changed & IEEE802515_AFILT_IEEEADDR_CHANGED) {
480 		/* Device Address */
481 		int i;
482 		for (i = 0; i < 8; i++)
483 			write_short_reg(devrec, REG_EADR0+i,
484 					filt->ieee_addr[7-i]);
485 
486 #ifdef DEBUG
487 		printk(KERN_DEBUG "Set long addr to: ");
488 		for (i = 0; i < 8; i++)
489 			printk("%02hhx ", filt->ieee_addr[i]);
490 		printk(KERN_DEBUG "\n");
491 #endif
492 	}
493 
494 	if (changed & IEEE802515_AFILT_PANID_CHANGED) {
495 		/* PAN ID */
496 		u8 panidl, panidh;
497 		panidh = filt->pan_id >> 8 & 0xff;
498 		panidl = filt->pan_id & 0xff;
499 		write_short_reg(devrec, REG_PANIDH, panidh);
500 		write_short_reg(devrec, REG_PANIDL, panidl);
501 
502 		dev_dbg(printdev(devrec), "Set PANID to %04hx\n", filt->pan_id);
503 	}
504 
505 	if (changed & IEEE802515_AFILT_PANC_CHANGED) {
506 		/* Pan Coordinator */
507 		u8 val;
508 		int ret;
509 
510 		ret = read_short_reg(devrec, REG_RXMCR, &val);
511 		if (ret)
512 			return ret;
513 		if (filt->pan_coord)
514 			val |= 0x8;
515 		else
516 			val &= ~0x8;
517 		write_short_reg(devrec, REG_RXMCR, val);
518 
519 		/* REG_SLOTTED is maintained as default (unslotted/CSMA-CA).
520 		 * REG_ORDER is maintained as default (no beacon/superframe).
521 		 */
522 
523 		dev_dbg(printdev(devrec), "Set Pan Coord to %s\n",
524 					filt->pan_coord ? "on" : "off");
525 	}
526 
527 	return 0;
528 }
529 
530 static int mrf24j40_handle_rx(struct mrf24j40 *devrec)
531 {
532 	u8 len = RX_FIFO_SIZE;
533 	u8 lqi = 0;
534 	u8 val;
535 	int ret = 0;
536 	struct sk_buff *skb;
537 
538 	/* Turn off reception of packets off the air. This prevents the
539 	 * device from overwriting the buffer while we're reading it. */
540 	ret = read_short_reg(devrec, REG_BBREG1, &val);
541 	if (ret)
542 		goto out;
543 	val |= 4; /* SET RXDECINV */
544 	write_short_reg(devrec, REG_BBREG1, val);
545 
546 	skb = alloc_skb(len, GFP_KERNEL);
547 	if (!skb) {
548 		ret = -ENOMEM;
549 		goto out;
550 	}
551 
552 	ret = mrf24j40_read_rx_buf(devrec, skb_put(skb, len), &len, &lqi);
553 	if (ret < 0) {
554 		dev_err(printdev(devrec), "Failure reading RX FIFO\n");
555 		kfree_skb(skb);
556 		ret = -EINVAL;
557 		goto out;
558 	}
559 
560 	/* Cut off the checksum */
561 	skb_trim(skb, len-2);
562 
563 	/* TODO: Other drivers call ieee20154_rx_irqsafe() here (eg: cc2040,
564 	 * also from a workqueue).  I think irqsafe is not necessary here.
565 	 * Can someone confirm? */
566 	ieee802154_rx_irqsafe(devrec->dev, skb, lqi);
567 
568 	dev_dbg(printdev(devrec), "RX Handled\n");
569 
570 out:
571 	/* Turn back on reception of packets off the air. */
572 	ret = read_short_reg(devrec, REG_BBREG1, &val);
573 	if (ret)
574 		return ret;
575 	val &= ~0x4; /* Clear RXDECINV */
576 	write_short_reg(devrec, REG_BBREG1, val);
577 
578 	return ret;
579 }
580 
581 static struct ieee802154_ops mrf24j40_ops = {
582 	.owner = THIS_MODULE,
583 	.xmit = mrf24j40_tx,
584 	.ed = mrf24j40_ed,
585 	.start = mrf24j40_start,
586 	.stop = mrf24j40_stop,
587 	.set_channel = mrf24j40_set_channel,
588 	.set_hw_addr_filt = mrf24j40_filter,
589 };
590 
591 static irqreturn_t mrf24j40_isr(int irq, void *data)
592 {
593 	struct mrf24j40 *devrec = data;
594 
595 	disable_irq_nosync(irq);
596 
597 	schedule_work(&devrec->irqwork);
598 
599 	return IRQ_HANDLED;
600 }
601 
602 static void mrf24j40_isrwork(struct work_struct *work)
603 {
604 	struct mrf24j40 *devrec = container_of(work, struct mrf24j40, irqwork);
605 	u8 intstat;
606 	int ret;
607 
608 	/* Read the interrupt status */
609 	ret = read_short_reg(devrec, REG_INTSTAT, &intstat);
610 	if (ret)
611 		goto out;
612 
613 	/* Check for TX complete */
614 	if (intstat & 0x1)
615 		complete(&devrec->tx_complete);
616 
617 	/* Check for Rx */
618 	if (intstat & 0x8)
619 		mrf24j40_handle_rx(devrec);
620 
621 out:
622 	enable_irq(devrec->spi->irq);
623 }
624 
625 static int mrf24j40_probe(struct spi_device *spi)
626 {
627 	int ret = -ENOMEM;
628 	u8 val;
629 	struct mrf24j40 *devrec;
630 	struct pinctrl *pinctrl;
631 
632 	printk(KERN_INFO "mrf24j40: probe(). IRQ: %d\n", spi->irq);
633 
634 	devrec = kzalloc(sizeof(struct mrf24j40), GFP_KERNEL);
635 	if (!devrec)
636 		goto err_devrec;
637 	devrec->buf = kzalloc(3, GFP_KERNEL);
638 	if (!devrec->buf)
639 		goto err_buf;
640 
641 	pinctrl = devm_pinctrl_get_select_default(&spi->dev);
642 	if (IS_ERR(pinctrl))
643 		dev_warn(&spi->dev,
644 			"pinctrl pins are not configured from the driver");
645 
646 	spi->mode = SPI_MODE_0; /* TODO: Is this appropriate for right here? */
647 	if (spi->max_speed_hz > MAX_SPI_SPEED_HZ)
648 		spi->max_speed_hz = MAX_SPI_SPEED_HZ;
649 
650 	mutex_init(&devrec->buffer_mutex);
651 	init_completion(&devrec->tx_complete);
652 	INIT_WORK(&devrec->irqwork, mrf24j40_isrwork);
653 	devrec->spi = spi;
654 	spi_set_drvdata(spi, devrec);
655 
656 	/* Register with the 802154 subsystem */
657 
658 	devrec->dev = ieee802154_alloc_device(0, &mrf24j40_ops);
659 	if (!devrec->dev)
660 		goto err_alloc_dev;
661 
662 	devrec->dev->priv = devrec;
663 	devrec->dev->parent = &devrec->spi->dev;
664 	devrec->dev->phy->channels_supported[0] = CHANNEL_MASK;
665 	devrec->dev->flags = IEEE802154_HW_OMIT_CKSUM|IEEE802154_HW_AACK;
666 
667 	dev_dbg(printdev(devrec), "registered mrf24j40\n");
668 	ret = ieee802154_register_device(devrec->dev);
669 	if (ret)
670 		goto err_register_device;
671 
672 	/* Initialize the device.
673 		From datasheet section 3.2: Initialization. */
674 	write_short_reg(devrec, REG_SOFTRST, 0x07);
675 	write_short_reg(devrec, REG_PACON2, 0x98);
676 	write_short_reg(devrec, REG_TXSTBL, 0x95);
677 	write_long_reg(devrec, REG_RFCON0, 0x03);
678 	write_long_reg(devrec, REG_RFCON1, 0x01);
679 	write_long_reg(devrec, REG_RFCON2, 0x80);
680 	write_long_reg(devrec, REG_RFCON6, 0x90);
681 	write_long_reg(devrec, REG_RFCON7, 0x80);
682 	write_long_reg(devrec, REG_RFCON8, 0x10);
683 	write_long_reg(devrec, REG_SLPCON1, 0x21);
684 	write_short_reg(devrec, REG_BBREG2, 0x80);
685 	write_short_reg(devrec, REG_CCAEDTH, 0x60);
686 	write_short_reg(devrec, REG_BBREG6, 0x40);
687 	write_short_reg(devrec, REG_RFCTL, 0x04);
688 	write_short_reg(devrec, REG_RFCTL, 0x0);
689 	udelay(192);
690 
691 	/* Set RX Mode. RXMCR<1:0>: 0x0 normal, 0x1 promisc, 0x2 error */
692 	ret = read_short_reg(devrec, REG_RXMCR, &val);
693 	if (ret)
694 		goto err_read_reg;
695 	val &= ~0x3; /* Clear RX mode (normal) */
696 	write_short_reg(devrec, REG_RXMCR, val);
697 
698 	ret = request_irq(spi->irq,
699 			  mrf24j40_isr,
700 			  IRQF_TRIGGER_FALLING,
701 			  dev_name(&spi->dev),
702 			  devrec);
703 
704 	if (ret) {
705 		dev_err(printdev(devrec), "Unable to get IRQ");
706 		goto err_irq;
707 	}
708 
709 	return 0;
710 
711 err_irq:
712 err_read_reg:
713 	ieee802154_unregister_device(devrec->dev);
714 err_register_device:
715 	ieee802154_free_device(devrec->dev);
716 err_alloc_dev:
717 	kfree(devrec->buf);
718 err_buf:
719 	kfree(devrec);
720 err_devrec:
721 	return ret;
722 }
723 
724 static int mrf24j40_remove(struct spi_device *spi)
725 {
726 	struct mrf24j40 *devrec = spi_get_drvdata(spi);
727 
728 	dev_dbg(printdev(devrec), "remove\n");
729 
730 	free_irq(spi->irq, devrec);
731 	flush_work(&devrec->irqwork); /* TODO: Is this the right call? */
732 	ieee802154_unregister_device(devrec->dev);
733 	ieee802154_free_device(devrec->dev);
734 	/* TODO: Will ieee802154_free_device() wait until ->xmit() is
735 	 * complete? */
736 
737 	/* Clean up the SPI stuff. */
738 	spi_set_drvdata(spi, NULL);
739 	kfree(devrec->buf);
740 	kfree(devrec);
741 	return 0;
742 }
743 
744 static const struct spi_device_id mrf24j40_ids[] = {
745 	{ "mrf24j40", 0 },
746 	{ "mrf24j40ma", 0 },
747 	{ },
748 };
749 MODULE_DEVICE_TABLE(spi, mrf24j40_ids);
750 
751 static struct spi_driver mrf24j40_driver = {
752 	.driver = {
753 		.name = "mrf24j40",
754 		.bus = &spi_bus_type,
755 		.owner = THIS_MODULE,
756 	},
757 	.id_table = mrf24j40_ids,
758 	.probe = mrf24j40_probe,
759 	.remove = mrf24j40_remove,
760 };
761 
762 module_spi_driver(mrf24j40_driver);
763 
764 MODULE_LICENSE("GPL");
765 MODULE_AUTHOR("Alan Ott");
766 MODULE_DESCRIPTION("MRF24J40 SPI 802.15.4 Controller Driver");
767