1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Register map access API - ENCX24J600 support
4  *
5  * Copyright 2015 Gridpoint
6  *
7  * Author: Jon Ringle <jringle@gridpoint.com>
8  */
9 
10 #include <linux/delay.h>
11 #include <linux/errno.h>
12 #include <linux/init.h>
13 #include <linux/module.h>
14 #include <linux/netdevice.h>
15 #include <linux/regmap.h>
16 #include <linux/spi/spi.h>
17 
18 #include "encx24j600_hw.h"
19 
20 static int encx24j600_switch_bank(struct encx24j600_context *ctx,
21 				  int bank)
22 {
23 	int ret = 0;
24 	int bank_opcode = BANK_SELECT(bank);
25 
26 	ret = spi_write(ctx->spi, &bank_opcode, 1);
27 	if (ret == 0)
28 		ctx->bank = bank;
29 
30 	return ret;
31 }
32 
33 static int encx24j600_cmdn(struct encx24j600_context *ctx, u8 opcode,
34 			   const void *buf, size_t len)
35 {
36 	struct spi_message m;
37 	struct spi_transfer t[2] = { { .tx_buf = &opcode, .len = 1, },
38 				     { .tx_buf = buf, .len = len }, };
39 	spi_message_init(&m);
40 	spi_message_add_tail(&t[0], &m);
41 	spi_message_add_tail(&t[1], &m);
42 
43 	return spi_sync(ctx->spi, &m);
44 }
45 
46 static void regmap_lock_mutex(void *context)
47 {
48 	struct encx24j600_context *ctx = context;
49 
50 	mutex_lock(&ctx->mutex);
51 }
52 
53 static void regmap_unlock_mutex(void *context)
54 {
55 	struct encx24j600_context *ctx = context;
56 
57 	mutex_unlock(&ctx->mutex);
58 }
59 
60 static int regmap_encx24j600_sfr_read(void *context, u8 reg, u8 *val,
61 				      size_t len)
62 {
63 	struct encx24j600_context *ctx = context;
64 	u8 banked_reg = reg & ADDR_MASK;
65 	u8 bank = ((reg & BANK_MASK) >> BANK_SHIFT);
66 	u8 cmd = RCRU;
67 	int ret = 0;
68 	int i = 0;
69 	u8 tx_buf[2];
70 
71 	if (reg < 0x80) {
72 		cmd = RCRCODE | banked_reg;
73 		if ((banked_reg < 0x16) && (ctx->bank != bank))
74 			ret = encx24j600_switch_bank(ctx, bank);
75 		if (unlikely(ret))
76 			return ret;
77 	} else {
78 		/* Translate registers that are more effecient using
79 		 * 3-byte SPI commands
80 		 */
81 		switch (reg) {
82 		case EGPRDPT:
83 			cmd = RGPRDPT; break;
84 		case EGPWRPT:
85 			cmd = RGPWRPT; break;
86 		case ERXRDPT:
87 			cmd = RRXRDPT; break;
88 		case ERXWRPT:
89 			cmd = RRXWRPT; break;
90 		case EUDARDPT:
91 			cmd = RUDARDPT; break;
92 		case EUDAWRPT:
93 			cmd = RUDAWRPT; break;
94 		case EGPDATA:
95 		case ERXDATA:
96 		case EUDADATA:
97 		default:
98 			return -EINVAL;
99 		}
100 	}
101 
102 	tx_buf[i++] = cmd;
103 	if (cmd == RCRU)
104 		tx_buf[i++] = reg;
105 
106 	ret = spi_write_then_read(ctx->spi, tx_buf, i, val, len);
107 
108 	return ret;
109 }
110 
111 static int regmap_encx24j600_sfr_update(struct encx24j600_context *ctx,
112 					u8 reg, u8 *val, size_t len,
113 					u8 unbanked_cmd, u8 banked_code)
114 {
115 	u8 banked_reg = reg & ADDR_MASK;
116 	u8 bank = ((reg & BANK_MASK) >> BANK_SHIFT);
117 	u8 cmd = unbanked_cmd;
118 	struct spi_message m;
119 	struct spi_transfer t[3] = { { .tx_buf = &cmd, .len = sizeof(cmd), },
120 				     { .tx_buf = &reg, .len = sizeof(reg), },
121 				     { .tx_buf = val, .len = len }, };
122 
123 	if (reg < 0x80) {
124 		int ret = 0;
125 
126 		cmd = banked_code | banked_reg;
127 		if ((banked_reg < 0x16) && (ctx->bank != bank))
128 			ret = encx24j600_switch_bank(ctx, bank);
129 		if (unlikely(ret))
130 			return ret;
131 	} else {
132 		/* Translate registers that are more effecient using
133 		 * 3-byte SPI commands
134 		 */
135 		switch (reg) {
136 		case EGPRDPT:
137 			cmd = WGPRDPT; break;
138 		case EGPWRPT:
139 			cmd = WGPWRPT; break;
140 		case ERXRDPT:
141 			cmd = WRXRDPT; break;
142 		case ERXWRPT:
143 			cmd = WRXWRPT; break;
144 		case EUDARDPT:
145 			cmd = WUDARDPT; break;
146 		case EUDAWRPT:
147 			cmd = WUDAWRPT; break;
148 		case EGPDATA:
149 		case ERXDATA:
150 		case EUDADATA:
151 		default:
152 			return -EINVAL;
153 		}
154 	}
155 
156 	spi_message_init(&m);
157 	spi_message_add_tail(&t[0], &m);
158 
159 	if (cmd == unbanked_cmd) {
160 		t[1].tx_buf = &reg;
161 		spi_message_add_tail(&t[1], &m);
162 	}
163 
164 	spi_message_add_tail(&t[2], &m);
165 	return spi_sync(ctx->spi, &m);
166 }
167 
168 static int regmap_encx24j600_sfr_write(void *context, u8 reg, u8 *val,
169 				       size_t len)
170 {
171 	struct encx24j600_context *ctx = context;
172 
173 	return regmap_encx24j600_sfr_update(ctx, reg, val, len, WCRU, WCRCODE);
174 }
175 
176 static int regmap_encx24j600_sfr_set_bits(struct encx24j600_context *ctx,
177 					  u8 reg, u8 val)
178 {
179 	return regmap_encx24j600_sfr_update(ctx, reg, &val, 1, BFSU, BFSCODE);
180 }
181 
182 static int regmap_encx24j600_sfr_clr_bits(struct encx24j600_context *ctx,
183 					  u8 reg, u8 val)
184 {
185 	return regmap_encx24j600_sfr_update(ctx, reg, &val, 1, BFCU, BFCCODE);
186 }
187 
188 static int regmap_encx24j600_reg_update_bits(void *context, unsigned int reg,
189 					     unsigned int mask,
190 					     unsigned int val)
191 {
192 	struct encx24j600_context *ctx = context;
193 
194 	int ret = 0;
195 	unsigned int set_mask = mask & val;
196 	unsigned int clr_mask = mask & ~val;
197 
198 	if ((reg >= 0x40 && reg < 0x6c) || reg >= 0x80)
199 		return -EINVAL;
200 
201 	if (set_mask & 0xff)
202 		ret = regmap_encx24j600_sfr_set_bits(ctx, reg, set_mask);
203 
204 	set_mask = (set_mask & 0xff00) >> 8;
205 
206 	if ((set_mask & 0xff) && (ret == 0))
207 		ret = regmap_encx24j600_sfr_set_bits(ctx, reg + 1, set_mask);
208 
209 	if ((clr_mask & 0xff) && (ret == 0))
210 		ret = regmap_encx24j600_sfr_clr_bits(ctx, reg, clr_mask);
211 
212 	clr_mask = (clr_mask & 0xff00) >> 8;
213 
214 	if ((clr_mask & 0xff) && (ret == 0))
215 		ret = regmap_encx24j600_sfr_clr_bits(ctx, reg + 1, clr_mask);
216 
217 	return ret;
218 }
219 
220 int regmap_encx24j600_spi_write(void *context, u8 reg, const u8 *data,
221 				size_t count)
222 {
223 	struct encx24j600_context *ctx = context;
224 
225 	if (reg < 0xc0)
226 		return encx24j600_cmdn(ctx, reg, data, count);
227 
228 	/* SPI 1-byte command. Ignore data */
229 	return spi_write(ctx->spi, &reg, 1);
230 }
231 EXPORT_SYMBOL_GPL(regmap_encx24j600_spi_write);
232 
233 int regmap_encx24j600_spi_read(void *context, u8 reg, u8 *data, size_t count)
234 {
235 	struct encx24j600_context *ctx = context;
236 
237 	if (reg == RBSEL && count > 1)
238 		count = 1;
239 
240 	return spi_write_then_read(ctx->spi, &reg, sizeof(reg), data, count);
241 }
242 EXPORT_SYMBOL_GPL(regmap_encx24j600_spi_read);
243 
244 static int regmap_encx24j600_write(void *context, const void *data,
245 				   size_t len)
246 {
247 	u8 *dout = (u8 *)data;
248 	u8 reg = dout[0];
249 	++dout;
250 	--len;
251 
252 	if (reg > 0xa0)
253 		return regmap_encx24j600_spi_write(context, reg, dout, len);
254 
255 	if (len > 2)
256 		return -EINVAL;
257 
258 	return regmap_encx24j600_sfr_write(context, reg, dout, len);
259 }
260 
261 static int regmap_encx24j600_read(void *context,
262 				  const void *reg_buf, size_t reg_size,
263 				  void *val, size_t val_size)
264 {
265 	u8 reg = *(const u8 *)reg_buf;
266 
267 	if (reg_size != 1) {
268 		pr_err("%s: reg=%02x reg_size=%zu\n", __func__, reg, reg_size);
269 		return -EINVAL;
270 	}
271 
272 	if (reg > 0xa0)
273 		return regmap_encx24j600_spi_read(context, reg, val, val_size);
274 
275 	if (val_size > 2) {
276 		pr_err("%s: reg=%02x val_size=%zu\n", __func__, reg, val_size);
277 		return -EINVAL;
278 	}
279 
280 	return regmap_encx24j600_sfr_read(context, reg, val, val_size);
281 }
282 
283 static bool encx24j600_regmap_readable(struct device *dev, unsigned int reg)
284 {
285 	if ((reg < 0x36) ||
286 	    ((reg >= 0x40) && (reg < 0x4c)) ||
287 	    ((reg >= 0x52) && (reg < 0x56)) ||
288 	    ((reg >= 0x60) && (reg < 0x66)) ||
289 	    ((reg >= 0x68) && (reg < 0x80)) ||
290 	    ((reg >= 0x86) && (reg < 0x92)) ||
291 	    (reg == 0xc8))
292 		return true;
293 	else
294 		return false;
295 }
296 
297 static bool encx24j600_regmap_writeable(struct device *dev, unsigned int reg)
298 {
299 	if ((reg < 0x12) ||
300 	    ((reg >= 0x14) && (reg < 0x1a)) ||
301 	    ((reg >= 0x1c) && (reg < 0x36)) ||
302 	    ((reg >= 0x40) && (reg < 0x4c)) ||
303 	    ((reg >= 0x52) && (reg < 0x56)) ||
304 	    ((reg >= 0x60) && (reg < 0x68)) ||
305 	    ((reg >= 0x6c) && (reg < 0x80)) ||
306 	    ((reg >= 0x86) && (reg < 0x92)) ||
307 	    ((reg >= 0xc0) && (reg < 0xc8)) ||
308 	    ((reg >= 0xca) && (reg < 0xf0)))
309 		return true;
310 	else
311 		return false;
312 }
313 
314 static bool encx24j600_regmap_volatile(struct device *dev, unsigned int reg)
315 {
316 	switch (reg) {
317 	case ERXHEAD:
318 	case EDMACS:
319 	case ETXSTAT:
320 	case ETXWIRE:
321 	case ECON1:	/* Can be modified via single byte cmds */
322 	case ECON2:	/* Can be modified via single byte cmds */
323 	case ESTAT:
324 	case EIR:	/* Can be modified via single byte cmds */
325 	case MIRD:
326 	case MISTAT:
327 		return true;
328 	default:
329 		break;
330 	}
331 
332 	return false;
333 }
334 
335 static bool encx24j600_regmap_precious(struct device *dev, unsigned int reg)
336 {
337 	/* single byte cmds are precious */
338 	if (((reg >= 0xc0) && (reg < 0xc8)) ||
339 	    ((reg >= 0xca) && (reg < 0xf0)))
340 		return true;
341 	else
342 		return false;
343 }
344 
345 static int regmap_encx24j600_phy_reg_read(void *context, unsigned int reg,
346 					  unsigned int *val)
347 {
348 	struct encx24j600_context *ctx = context;
349 	int ret;
350 	unsigned int mistat;
351 
352 	reg = MIREGADR_VAL | (reg & PHREG_MASK);
353 	ret = regmap_write(ctx->regmap, MIREGADR, reg);
354 	if (unlikely(ret))
355 		goto err_out;
356 
357 	ret = regmap_write(ctx->regmap, MICMD, MIIRD);
358 	if (unlikely(ret))
359 		goto err_out;
360 
361 	usleep_range(26, 100);
362 	while (((ret = regmap_read(ctx->regmap, MISTAT, &mistat)) == 0) &&
363 	       (mistat & BUSY))
364 		cpu_relax();
365 
366 	if (unlikely(ret))
367 		goto err_out;
368 
369 	ret = regmap_write(ctx->regmap, MICMD, 0);
370 	if (unlikely(ret))
371 		goto err_out;
372 
373 	ret = regmap_read(ctx->regmap, MIRD, val);
374 
375 err_out:
376 	if (ret)
377 		pr_err("%s: error %d reading reg %02x\n", __func__, ret,
378 		       reg & PHREG_MASK);
379 
380 	return ret;
381 }
382 
383 static int regmap_encx24j600_phy_reg_write(void *context, unsigned int reg,
384 					   unsigned int val)
385 {
386 	struct encx24j600_context *ctx = context;
387 	int ret;
388 	unsigned int mistat;
389 
390 	reg = MIREGADR_VAL | (reg & PHREG_MASK);
391 	ret = regmap_write(ctx->regmap, MIREGADR, reg);
392 	if (unlikely(ret))
393 		goto err_out;
394 
395 	ret = regmap_write(ctx->regmap, MIWR, val);
396 	if (unlikely(ret))
397 		goto err_out;
398 
399 	usleep_range(26, 100);
400 	while (((ret = regmap_read(ctx->regmap, MISTAT, &mistat)) == 0) &&
401 	       (mistat & BUSY))
402 		cpu_relax();
403 
404 err_out:
405 	if (ret)
406 		pr_err("%s: error %d writing reg %02x=%04x\n", __func__, ret,
407 		       reg & PHREG_MASK, val);
408 
409 	return ret;
410 }
411 
412 static bool encx24j600_phymap_readable(struct device *dev, unsigned int reg)
413 {
414 	switch (reg) {
415 	case PHCON1:
416 	case PHSTAT1:
417 	case PHANA:
418 	case PHANLPA:
419 	case PHANE:
420 	case PHCON2:
421 	case PHSTAT2:
422 	case PHSTAT3:
423 		return true;
424 	default:
425 		return false;
426 	}
427 }
428 
429 static bool encx24j600_phymap_writeable(struct device *dev, unsigned int reg)
430 {
431 	switch (reg) {
432 	case PHCON1:
433 	case PHCON2:
434 	case PHANA:
435 		return true;
436 	case PHSTAT1:
437 	case PHSTAT2:
438 	case PHSTAT3:
439 	case PHANLPA:
440 	case PHANE:
441 	default:
442 		return false;
443 	}
444 }
445 
446 static bool encx24j600_phymap_volatile(struct device *dev, unsigned int reg)
447 {
448 	switch (reg) {
449 	case PHSTAT1:
450 	case PHSTAT2:
451 	case PHSTAT3:
452 	case PHANLPA:
453 	case PHANE:
454 	case PHCON2:
455 		return true;
456 	default:
457 		return false;
458 	}
459 }
460 
461 static struct regmap_config regcfg = {
462 	.name = "reg",
463 	.reg_bits = 8,
464 	.val_bits = 16,
465 	.max_register = 0xee,
466 	.reg_stride = 2,
467 	.cache_type = REGCACHE_RBTREE,
468 	.val_format_endian = REGMAP_ENDIAN_LITTLE,
469 	.readable_reg = encx24j600_regmap_readable,
470 	.writeable_reg = encx24j600_regmap_writeable,
471 	.volatile_reg = encx24j600_regmap_volatile,
472 	.precious_reg = encx24j600_regmap_precious,
473 	.lock = regmap_lock_mutex,
474 	.unlock = regmap_unlock_mutex,
475 };
476 
477 static struct regmap_bus regmap_encx24j600 = {
478 	.write = regmap_encx24j600_write,
479 	.read = regmap_encx24j600_read,
480 	.reg_update_bits = regmap_encx24j600_reg_update_bits,
481 };
482 
483 static struct regmap_config phycfg = {
484 	.name = "phy",
485 	.reg_bits = 8,
486 	.val_bits = 16,
487 	.max_register = 0x1f,
488 	.cache_type = REGCACHE_RBTREE,
489 	.val_format_endian = REGMAP_ENDIAN_LITTLE,
490 	.readable_reg = encx24j600_phymap_readable,
491 	.writeable_reg = encx24j600_phymap_writeable,
492 	.volatile_reg = encx24j600_phymap_volatile,
493 };
494 
495 static struct regmap_bus phymap_encx24j600 = {
496 	.reg_write = regmap_encx24j600_phy_reg_write,
497 	.reg_read = regmap_encx24j600_phy_reg_read,
498 };
499 
500 int devm_regmap_init_encx24j600(struct device *dev,
501 				struct encx24j600_context *ctx)
502 {
503 	mutex_init(&ctx->mutex);
504 	regcfg.lock_arg = ctx;
505 	ctx->regmap = devm_regmap_init(dev, &regmap_encx24j600, ctx, &regcfg);
506 	if (IS_ERR(ctx->regmap))
507 		return PTR_ERR(ctx->regmap);
508 	ctx->phymap = devm_regmap_init(dev, &phymap_encx24j600, ctx, &phycfg);
509 	if (IS_ERR(ctx->phymap))
510 		return PTR_ERR(ctx->phymap);
511 
512 	return 0;
513 }
514 EXPORT_SYMBOL_GPL(devm_regmap_init_encx24j600);
515 
516 MODULE_LICENSE("GPL");
517