xref: /linux/drivers/net/ieee802154/mrf24j40.c (revision 84a73014d86fd660822a20c032625e3afe99ca58)
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 
18 #include <linux/spi/spi.h>
19 #include <linux/interrupt.h>
20 #include <linux/module.h>
21 #include <linux/ieee802154.h>
22 #include <net/cfg802154.h>
23 #include <net/mac802154.h>
24 
25 /* MRF24J40 Short Address Registers */
26 #define REG_RXMCR    0x00  /* Receive MAC control */
27 #define REG_PANIDL   0x01  /* PAN ID (low) */
28 #define REG_PANIDH   0x02  /* PAN ID (high) */
29 #define REG_SADRL    0x03  /* Short address (low) */
30 #define REG_SADRH    0x04  /* Short address (high) */
31 #define REG_EADR0    0x05  /* Long address (low) (high is EADR7) */
32 #define REG_TXMCR    0x11  /* Transmit MAC control */
33 #define REG_PACON0   0x16  /* Power Amplifier Control */
34 #define REG_PACON1   0x17  /* Power Amplifier Control */
35 #define REG_PACON2   0x18  /* Power Amplifier Control */
36 #define REG_TXNCON   0x1B  /* Transmit Normal FIFO Control */
37 #define REG_TXSTAT   0x24  /* TX MAC Status Register */
38 #define REG_SOFTRST  0x2A  /* Soft Reset */
39 #define REG_TXSTBL   0x2E  /* TX Stabilization */
40 #define REG_INTSTAT  0x31  /* Interrupt Status */
41 #define REG_INTCON   0x32  /* Interrupt Control */
42 #define REG_GPIO     0x33  /* GPIO */
43 #define REG_TRISGPIO 0x34  /* GPIO direction */
44 #define REG_RFCTL    0x36  /* RF Control Mode Register */
45 #define REG_BBREG1   0x39  /* Baseband Registers */
46 #define REG_BBREG2   0x3A  /* */
47 #define REG_BBREG6   0x3E  /* */
48 #define REG_CCAEDTH  0x3F  /* Energy Detection Threshold */
49 
50 /* MRF24J40 Long Address Registers */
51 #define REG_RFCON0     0x200  /* RF Control Registers */
52 #define REG_RFCON1     0x201
53 #define REG_RFCON2     0x202
54 #define REG_RFCON3     0x203
55 #define REG_RFCON5     0x205
56 #define REG_RFCON6     0x206
57 #define REG_RFCON7     0x207
58 #define REG_RFCON8     0x208
59 #define REG_RSSI       0x210
60 #define REG_SLPCON0    0x211  /* Sleep Clock Control Registers */
61 #define REG_SLPCON1    0x220
62 #define REG_WAKETIMEL  0x222  /* Wake-up Time Match Value Low */
63 #define REG_WAKETIMEH  0x223  /* Wake-up Time Match Value High */
64 #define REG_TESTMODE   0x22F  /* Test mode */
65 #define REG_RX_FIFO    0x300  /* Receive FIFO */
66 
67 /* Device configuration: Only channels 11-26 on page 0 are supported. */
68 #define MRF24J40_CHAN_MIN 11
69 #define MRF24J40_CHAN_MAX 26
70 #define CHANNEL_MASK (((u32)1 << (MRF24J40_CHAN_MAX + 1)) \
71 		      - ((u32)1 << MRF24J40_CHAN_MIN))
72 
73 #define TX_FIFO_SIZE 128 /* From datasheet */
74 #define RX_FIFO_SIZE 144 /* From datasheet */
75 #define SET_CHANNEL_DELAY_US 192 /* From datasheet */
76 
77 enum mrf24j40_modules { MRF24J40, MRF24J40MA, MRF24J40MC };
78 
79 /* Device Private Data */
80 struct mrf24j40 {
81 	struct spi_device *spi;
82 	struct ieee802154_hw *hw;
83 
84 	struct mutex buffer_mutex; /* only used to protect buf */
85 	struct completion tx_complete;
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 beginning. */
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 	pr_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_hw *hw, struct sk_buff *skb)
336 {
337 	struct mrf24j40 *devrec = hw->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 	reinit_completion(&devrec->tx_complete);
348 
349 	/* Set TXNTRIG bit of TXNCON to send packet */
350 	ret = read_short_reg(devrec, REG_TXNCON, &val);
351 	if (ret)
352 		goto err;
353 	val |= 0x1;
354 	/* Set TXNACKREQ if the ACK bit is set in the packet. */
355 	if (skb->data[0] & IEEE802154_FC_ACK_REQ)
356 		val |= 0x4;
357 	write_short_reg(devrec, REG_TXNCON, val);
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_hw *hw, u8 *level)
387 {
388 	/* TODO: */
389 	pr_warn("mrf24j40: ed not implemented\n");
390 	*level = 0;
391 	return 0;
392 }
393 
394 static int mrf24j40_start(struct ieee802154_hw *hw)
395 {
396 	struct mrf24j40 *devrec = hw->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_hw *hw)
412 {
413 	struct mrf24j40 *devrec = hw->priv;
414 	u8 val;
415 	int ret;
416 
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 
426 static int mrf24j40_set_channel(struct ieee802154_hw *hw, u8 page, u8 channel)
427 {
428 	struct mrf24j40 *devrec = hw->priv;
429 	u8 val;
430 	int ret;
431 
432 	dev_dbg(printdev(devrec), "Set Channel %d\n", channel);
433 
434 	WARN_ON(page != 0);
435 	WARN_ON(channel < MRF24J40_CHAN_MIN);
436 	WARN_ON(channel > MRF24J40_CHAN_MAX);
437 
438 	/* Set Channel TODO */
439 	val = (channel-11) << 4 | 0x03;
440 	write_long_reg(devrec, REG_RFCON0, val);
441 
442 	/* RF Reset */
443 	ret = read_short_reg(devrec, REG_RFCTL, &val);
444 	if (ret)
445 		return ret;
446 	val |= 0x04;
447 	write_short_reg(devrec, REG_RFCTL, val);
448 	val &= ~0x04;
449 	write_short_reg(devrec, REG_RFCTL, val);
450 
451 	udelay(SET_CHANNEL_DELAY_US); /* per datasheet */
452 
453 	return 0;
454 }
455 
456 static int mrf24j40_filter(struct ieee802154_hw *hw,
457 			   struct ieee802154_hw_addr_filt *filt,
458 			   unsigned long changed)
459 {
460 	struct mrf24j40 *devrec = hw->priv;
461 
462 	dev_dbg(printdev(devrec), "filter\n");
463 
464 	if (changed & IEEE802154_AFILT_SADDR_CHANGED) {
465 		/* Short Addr */
466 		u8 addrh, addrl;
467 
468 		addrh = le16_to_cpu(filt->short_addr) >> 8 & 0xff;
469 		addrl = le16_to_cpu(filt->short_addr) & 0xff;
470 
471 		write_short_reg(devrec, REG_SADRH, addrh);
472 		write_short_reg(devrec, REG_SADRL, addrl);
473 		dev_dbg(printdev(devrec),
474 			"Set short addr to %04hx\n", filt->short_addr);
475 	}
476 
477 	if (changed & IEEE802154_AFILT_IEEEADDR_CHANGED) {
478 		/* Device Address */
479 		u8 i, addr[8];
480 
481 		memcpy(addr, &filt->ieee_addr, 8);
482 		for (i = 0; i < 8; i++)
483 			write_short_reg(devrec, REG_EADR0 + i, addr[i]);
484 
485 #ifdef DEBUG
486 		pr_debug("Set long addr to: ");
487 		for (i = 0; i < 8; i++)
488 			pr_debug("%02hhx ", addr[7 - i]);
489 		pr_debug("\n");
490 #endif
491 	}
492 
493 	if (changed & IEEE802154_AFILT_PANID_CHANGED) {
494 		/* PAN ID */
495 		u8 panidl, panidh;
496 
497 		panidh = le16_to_cpu(filt->pan_id) >> 8 & 0xff;
498 		panidl = le16_to_cpu(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 & IEEE802154_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 	int ret2;
537 	struct sk_buff *skb;
538 
539 	/* Turn off reception of packets off the air. This prevents the
540 	 * device from overwriting the buffer while we're reading it. */
541 	ret = read_short_reg(devrec, REG_BBREG1, &val);
542 	if (ret)
543 		goto out;
544 	val |= 4; /* SET RXDECINV */
545 	write_short_reg(devrec, REG_BBREG1, val);
546 
547 	skb = dev_alloc_skb(len);
548 	if (!skb) {
549 		ret = -ENOMEM;
550 		goto out;
551 	}
552 
553 	ret = mrf24j40_read_rx_buf(devrec, skb_put(skb, len), &len, &lqi);
554 	if (ret < 0) {
555 		dev_err(printdev(devrec), "Failure reading RX FIFO\n");
556 		kfree_skb(skb);
557 		ret = -EINVAL;
558 		goto out;
559 	}
560 
561 	/* Cut off the checksum */
562 	skb_trim(skb, len-2);
563 
564 	/* TODO: Other drivers call ieee20154_rx_irqsafe() here (eg: cc2040,
565 	 * also from a workqueue).  I think irqsafe is not necessary here.
566 	 * Can someone confirm? */
567 	ieee802154_rx_irqsafe(devrec->hw, skb, lqi);
568 
569 	dev_dbg(printdev(devrec), "RX Handled\n");
570 
571 out:
572 	/* Turn back on reception of packets off the air. */
573 	ret2 = read_short_reg(devrec, REG_BBREG1, &val);
574 	if (ret2)
575 		return ret2;
576 	val &= ~0x4; /* Clear RXDECINV */
577 	write_short_reg(devrec, REG_BBREG1, val);
578 
579 	return ret;
580 }
581 
582 static const struct ieee802154_ops mrf24j40_ops = {
583 	.owner = THIS_MODULE,
584 	.xmit_sync = mrf24j40_tx,
585 	.ed = mrf24j40_ed,
586 	.start = mrf24j40_start,
587 	.stop = mrf24j40_stop,
588 	.set_channel = mrf24j40_set_channel,
589 	.set_hw_addr_filt = mrf24j40_filter,
590 };
591 
592 static irqreturn_t mrf24j40_isr(int irq, void *data)
593 {
594 	struct mrf24j40 *devrec = data;
595 	u8 intstat;
596 	int ret;
597 
598 	/* Read the interrupt status */
599 	ret = read_short_reg(devrec, REG_INTSTAT, &intstat);
600 	if (ret)
601 		goto out;
602 
603 	/* Check for TX complete */
604 	if (intstat & 0x1)
605 		complete(&devrec->tx_complete);
606 
607 	/* Check for Rx */
608 	if (intstat & 0x8)
609 		mrf24j40_handle_rx(devrec);
610 
611 out:
612 	return IRQ_HANDLED;
613 }
614 
615 static int mrf24j40_hw_init(struct mrf24j40 *devrec)
616 {
617 	int ret;
618 	u8 val;
619 
620 	/* Initialize the device.
621 		From datasheet section 3.2: Initialization. */
622 	ret = write_short_reg(devrec, REG_SOFTRST, 0x07);
623 	if (ret)
624 		goto err_ret;
625 
626 	ret = write_short_reg(devrec, REG_PACON2, 0x98);
627 	if (ret)
628 		goto err_ret;
629 
630 	ret = write_short_reg(devrec, REG_TXSTBL, 0x95);
631 	if (ret)
632 		goto err_ret;
633 
634 	ret = write_long_reg(devrec, REG_RFCON0, 0x03);
635 	if (ret)
636 		goto err_ret;
637 
638 	ret = write_long_reg(devrec, REG_RFCON1, 0x01);
639 	if (ret)
640 		goto err_ret;
641 
642 	ret = write_long_reg(devrec, REG_RFCON2, 0x80);
643 	if (ret)
644 		goto err_ret;
645 
646 	ret = write_long_reg(devrec, REG_RFCON6, 0x90);
647 	if (ret)
648 		goto err_ret;
649 
650 	ret = write_long_reg(devrec, REG_RFCON7, 0x80);
651 	if (ret)
652 		goto err_ret;
653 
654 	ret = write_long_reg(devrec, REG_RFCON8, 0x10);
655 	if (ret)
656 		goto err_ret;
657 
658 	ret = write_long_reg(devrec, REG_SLPCON1, 0x21);
659 	if (ret)
660 		goto err_ret;
661 
662 	ret = write_short_reg(devrec, REG_BBREG2, 0x80);
663 	if (ret)
664 		goto err_ret;
665 
666 	ret = write_short_reg(devrec, REG_CCAEDTH, 0x60);
667 	if (ret)
668 		goto err_ret;
669 
670 	ret = write_short_reg(devrec, REG_BBREG6, 0x40);
671 	if (ret)
672 		goto err_ret;
673 
674 	ret = write_short_reg(devrec, REG_RFCTL, 0x04);
675 	if (ret)
676 		goto err_ret;
677 
678 	ret = write_short_reg(devrec, REG_RFCTL, 0x0);
679 	if (ret)
680 		goto err_ret;
681 
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_ret;
688 
689 	val &= ~0x3; /* Clear RX mode (normal) */
690 
691 	ret = write_short_reg(devrec, REG_RXMCR, val);
692 	if (ret)
693 		goto err_ret;
694 
695 	if (spi_get_device_id(devrec->spi)->driver_data == MRF24J40MC) {
696 		/* Enable external amplifier.
697 		 * From MRF24J40MC datasheet section 1.3: Operation.
698 		 */
699 		read_long_reg(devrec, REG_TESTMODE, &val);
700 		val |= 0x7; /* Configure GPIO 0-2 to control amplifier */
701 		write_long_reg(devrec, REG_TESTMODE, val);
702 
703 		read_short_reg(devrec, REG_TRISGPIO, &val);
704 		val |= 0x8; /* Set GPIO3 as output. */
705 		write_short_reg(devrec, REG_TRISGPIO, val);
706 
707 		read_short_reg(devrec, REG_GPIO, &val);
708 		val |= 0x8; /* Set GPIO3 HIGH to enable U5 voltage regulator */
709 		write_short_reg(devrec, REG_GPIO, val);
710 
711 		/* Reduce TX pwr to meet FCC requirements.
712 		 * From MRF24J40MC datasheet section 3.1.1
713 		 */
714 		write_long_reg(devrec, REG_RFCON3, 0x28);
715 	}
716 
717 	return 0;
718 
719 err_ret:
720 	return ret;
721 }
722 
723 static int mrf24j40_probe(struct spi_device *spi)
724 {
725 	int ret = -ENOMEM;
726 	struct mrf24j40 *devrec;
727 
728 	dev_info(&spi->dev, "probe(). IRQ: %d\n", spi->irq);
729 
730 	devrec = devm_kzalloc(&spi->dev, sizeof(struct mrf24j40), GFP_KERNEL);
731 	if (!devrec)
732 		goto err_ret;
733 	devrec->buf = devm_kzalloc(&spi->dev, 3, GFP_KERNEL);
734 	if (!devrec->buf)
735 		goto err_ret;
736 
737 	spi->mode = SPI_MODE_0; /* TODO: Is this appropriate for right here? */
738 	if (spi->max_speed_hz > MAX_SPI_SPEED_HZ)
739 		spi->max_speed_hz = MAX_SPI_SPEED_HZ;
740 
741 	mutex_init(&devrec->buffer_mutex);
742 	init_completion(&devrec->tx_complete);
743 	devrec->spi = spi;
744 	spi_set_drvdata(spi, devrec);
745 
746 	/* Register with the 802154 subsystem */
747 
748 	devrec->hw = ieee802154_alloc_hw(0, &mrf24j40_ops);
749 	if (!devrec->hw)
750 		goto err_ret;
751 
752 	devrec->hw->priv = devrec;
753 	devrec->hw->parent = &devrec->spi->dev;
754 	devrec->hw->phy->supported.channels[0] = CHANNEL_MASK;
755 	devrec->hw->flags = IEEE802154_HW_OMIT_CKSUM | IEEE802154_HW_AFILT;
756 
757 	dev_dbg(printdev(devrec), "registered mrf24j40\n");
758 	ret = ieee802154_register_hw(devrec->hw);
759 	if (ret)
760 		goto err_register_device;
761 
762 	ret = mrf24j40_hw_init(devrec);
763 	if (ret)
764 		goto err_hw_init;
765 
766 	ret = devm_request_threaded_irq(&spi->dev,
767 					spi->irq,
768 					NULL,
769 					mrf24j40_isr,
770 					IRQF_TRIGGER_LOW|IRQF_ONESHOT,
771 					dev_name(&spi->dev),
772 					devrec);
773 
774 	if (ret) {
775 		dev_err(printdev(devrec), "Unable to get IRQ");
776 		goto err_irq;
777 	}
778 
779 	return 0;
780 
781 err_irq:
782 err_hw_init:
783 	ieee802154_unregister_hw(devrec->hw);
784 err_register_device:
785 	ieee802154_free_hw(devrec->hw);
786 err_ret:
787 	return ret;
788 }
789 
790 static int mrf24j40_remove(struct spi_device *spi)
791 {
792 	struct mrf24j40 *devrec = spi_get_drvdata(spi);
793 
794 	dev_dbg(printdev(devrec), "remove\n");
795 
796 	ieee802154_unregister_hw(devrec->hw);
797 	ieee802154_free_hw(devrec->hw);
798 	/* TODO: Will ieee802154_free_device() wait until ->xmit() is
799 	 * complete? */
800 
801 	return 0;
802 }
803 
804 static const struct spi_device_id mrf24j40_ids[] = {
805 	{ "mrf24j40", MRF24J40 },
806 	{ "mrf24j40ma", MRF24J40MA },
807 	{ "mrf24j40mc", MRF24J40MC },
808 	{ },
809 };
810 MODULE_DEVICE_TABLE(spi, mrf24j40_ids);
811 
812 static struct spi_driver mrf24j40_driver = {
813 	.driver = {
814 		.name = "mrf24j40",
815 		.owner = THIS_MODULE,
816 	},
817 	.id_table = mrf24j40_ids,
818 	.probe = mrf24j40_probe,
819 	.remove = mrf24j40_remove,
820 };
821 
822 module_spi_driver(mrf24j40_driver);
823 
824 MODULE_LICENSE("GPL");
825 MODULE_AUTHOR("Alan Ott");
826 MODULE_DESCRIPTION("MRF24J40 SPI 802.15.4 Controller Driver");
827