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