1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * SPI driver for Micrel/Kendin KS8995M and KSZ8864RMN ethernet switches
4 *
5 * Copyright (C) 2008 Gabor Juhos <juhosg at openwrt.org>
6 *
7 * This file was based on: drivers/spi/at25.c
8 * Copyright (C) 2006 David Brownell
9 */
10
11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12
13 #include <linux/types.h>
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/delay.h>
17 #include <linux/device.h>
18 #include <linux/gpio/consumer.h>
19 #include <linux/of.h>
20
21 #include <linux/spi/spi.h>
22
23 #define DRV_VERSION "0.1.1"
24 #define DRV_DESC "Micrel KS8995 Ethernet switch SPI driver"
25
26 /* ------------------------------------------------------------------------ */
27
28 #define KS8995_REG_ID0 0x00 /* Chip ID0 */
29 #define KS8995_REG_ID1 0x01 /* Chip ID1 */
30
31 #define KS8995_REG_GC0 0x02 /* Global Control 0 */
32 #define KS8995_REG_GC1 0x03 /* Global Control 1 */
33 #define KS8995_REG_GC2 0x04 /* Global Control 2 */
34 #define KS8995_REG_GC3 0x05 /* Global Control 3 */
35 #define KS8995_REG_GC4 0x06 /* Global Control 4 */
36 #define KS8995_REG_GC5 0x07 /* Global Control 5 */
37 #define KS8995_REG_GC6 0x08 /* Global Control 6 */
38 #define KS8995_REG_GC7 0x09 /* Global Control 7 */
39 #define KS8995_REG_GC8 0x0a /* Global Control 8 */
40 #define KS8995_REG_GC9 0x0b /* Global Control 9 */
41
42 #define KS8995_REG_PC(p, r) ((0x10 * p) + r) /* Port Control */
43 #define KS8995_REG_PS(p, r) ((0x10 * p) + r + 0xe) /* Port Status */
44
45 #define KS8995_REG_TPC0 0x60 /* TOS Priority Control 0 */
46 #define KS8995_REG_TPC1 0x61 /* TOS Priority Control 1 */
47 #define KS8995_REG_TPC2 0x62 /* TOS Priority Control 2 */
48 #define KS8995_REG_TPC3 0x63 /* TOS Priority Control 3 */
49 #define KS8995_REG_TPC4 0x64 /* TOS Priority Control 4 */
50 #define KS8995_REG_TPC5 0x65 /* TOS Priority Control 5 */
51 #define KS8995_REG_TPC6 0x66 /* TOS Priority Control 6 */
52 #define KS8995_REG_TPC7 0x67 /* TOS Priority Control 7 */
53
54 #define KS8995_REG_MAC0 0x68 /* MAC address 0 */
55 #define KS8995_REG_MAC1 0x69 /* MAC address 1 */
56 #define KS8995_REG_MAC2 0x6a /* MAC address 2 */
57 #define KS8995_REG_MAC3 0x6b /* MAC address 3 */
58 #define KS8995_REG_MAC4 0x6c /* MAC address 4 */
59 #define KS8995_REG_MAC5 0x6d /* MAC address 5 */
60
61 #define KS8995_REG_IAC0 0x6e /* Indirect Access Control 0 */
62 #define KS8995_REG_IAC1 0x6f /* Indirect Access Control 0 */
63 #define KS8995_REG_IAD7 0x70 /* Indirect Access Data 7 */
64 #define KS8995_REG_IAD6 0x71 /* Indirect Access Data 6 */
65 #define KS8995_REG_IAD5 0x72 /* Indirect Access Data 5 */
66 #define KS8995_REG_IAD4 0x73 /* Indirect Access Data 4 */
67 #define KS8995_REG_IAD3 0x74 /* Indirect Access Data 3 */
68 #define KS8995_REG_IAD2 0x75 /* Indirect Access Data 2 */
69 #define KS8995_REG_IAD1 0x76 /* Indirect Access Data 1 */
70 #define KS8995_REG_IAD0 0x77 /* Indirect Access Data 0 */
71
72 #define KSZ8864_REG_ID1 0xfe /* Chip ID in bit 7 */
73
74 #define KS8995_REGS_SIZE 0x80
75 #define KSZ8864_REGS_SIZE 0x100
76 #define KSZ8795_REGS_SIZE 0x100
77
78 #define ID1_CHIPID_M 0xf
79 #define ID1_CHIPID_S 4
80 #define ID1_REVISION_M 0x7
81 #define ID1_REVISION_S 1
82 #define ID1_START_SW 1 /* start the switch */
83
84 #define FAMILY_KS8995 0x95
85 #define FAMILY_KSZ8795 0x87
86 #define CHIPID_M 0
87 #define KS8995_CHIP_ID 0x00
88 #define KSZ8864_CHIP_ID 0x01
89 #define KSZ8795_CHIP_ID 0x09
90
91 #define KS8995_CMD_WRITE 0x02U
92 #define KS8995_CMD_READ 0x03U
93
94 #define KS8995_RESET_DELAY 10 /* usec */
95
96 enum ks8995_chip_variant {
97 ks8995,
98 ksz8864,
99 ksz8795,
100 max_variant
101 };
102
103 struct ks8995_chip_params {
104 char *name;
105 int family_id;
106 int chip_id;
107 int regs_size;
108 int addr_width;
109 int addr_shift;
110 };
111
112 static const struct ks8995_chip_params ks8995_chip[] = {
113 [ks8995] = {
114 .name = "KS8995MA",
115 .family_id = FAMILY_KS8995,
116 .chip_id = KS8995_CHIP_ID,
117 .regs_size = KS8995_REGS_SIZE,
118 .addr_width = 8,
119 .addr_shift = 0,
120 },
121 [ksz8864] = {
122 .name = "KSZ8864RMN",
123 .family_id = FAMILY_KS8995,
124 .chip_id = KSZ8864_CHIP_ID,
125 .regs_size = KSZ8864_REGS_SIZE,
126 .addr_width = 8,
127 .addr_shift = 0,
128 },
129 [ksz8795] = {
130 .name = "KSZ8795CLX",
131 .family_id = FAMILY_KSZ8795,
132 .chip_id = KSZ8795_CHIP_ID,
133 .regs_size = KSZ8795_REGS_SIZE,
134 .addr_width = 12,
135 .addr_shift = 1,
136 },
137 };
138
139 struct ks8995_switch {
140 struct spi_device *spi;
141 struct mutex lock;
142 struct gpio_desc *reset_gpio;
143 struct bin_attribute regs_attr;
144 const struct ks8995_chip_params *chip;
145 int revision_id;
146 };
147
148 static const struct spi_device_id ks8995_id[] = {
149 {"ks8995", ks8995},
150 {"ksz8864", ksz8864},
151 {"ksz8795", ksz8795},
152 { }
153 };
154 MODULE_DEVICE_TABLE(spi, ks8995_id);
155
156 static const struct of_device_id ks8895_spi_of_match[] = {
157 { .compatible = "micrel,ks8995" },
158 { .compatible = "micrel,ksz8864" },
159 { .compatible = "micrel,ksz8795" },
160 { },
161 };
162 MODULE_DEVICE_TABLE(of, ks8895_spi_of_match);
163
get_chip_id(u8 val)164 static inline u8 get_chip_id(u8 val)
165 {
166 return (val >> ID1_CHIPID_S) & ID1_CHIPID_M;
167 }
168
get_chip_rev(u8 val)169 static inline u8 get_chip_rev(u8 val)
170 {
171 return (val >> ID1_REVISION_S) & ID1_REVISION_M;
172 }
173
174 /* create_spi_cmd - create a chip specific SPI command header
175 * @ks: pointer to switch instance
176 * @cmd: SPI command for switch
177 * @address: register address for command
178 *
179 * Different chip families use different bit pattern to address the switches
180 * registers:
181 *
182 * KS8995: 8bit command + 8bit address
183 * KSZ8795: 3bit command + 12bit address + 1bit TR (?)
184 */
create_spi_cmd(struct ks8995_switch * ks,int cmd,unsigned address)185 static inline __be16 create_spi_cmd(struct ks8995_switch *ks, int cmd,
186 unsigned address)
187 {
188 u16 result = cmd;
189
190 /* make room for address (incl. address shift) */
191 result <<= ks->chip->addr_width + ks->chip->addr_shift;
192 /* add address */
193 result |= address << ks->chip->addr_shift;
194 /* SPI protocol needs big endian */
195 return cpu_to_be16(result);
196 }
197 /* ------------------------------------------------------------------------ */
ks8995_read(struct ks8995_switch * ks,char * buf,unsigned offset,size_t count)198 static int ks8995_read(struct ks8995_switch *ks, char *buf,
199 unsigned offset, size_t count)
200 {
201 __be16 cmd;
202 struct spi_transfer t[2];
203 struct spi_message m;
204 int err;
205
206 cmd = create_spi_cmd(ks, KS8995_CMD_READ, offset);
207 spi_message_init(&m);
208
209 memset(&t, 0, sizeof(t));
210
211 t[0].tx_buf = &cmd;
212 t[0].len = sizeof(cmd);
213 spi_message_add_tail(&t[0], &m);
214
215 t[1].rx_buf = buf;
216 t[1].len = count;
217 spi_message_add_tail(&t[1], &m);
218
219 mutex_lock(&ks->lock);
220 err = spi_sync(ks->spi, &m);
221 mutex_unlock(&ks->lock);
222
223 return err ? err : count;
224 }
225
ks8995_write(struct ks8995_switch * ks,char * buf,unsigned offset,size_t count)226 static int ks8995_write(struct ks8995_switch *ks, char *buf,
227 unsigned offset, size_t count)
228 {
229 __be16 cmd;
230 struct spi_transfer t[2];
231 struct spi_message m;
232 int err;
233
234 cmd = create_spi_cmd(ks, KS8995_CMD_WRITE, offset);
235 spi_message_init(&m);
236
237 memset(&t, 0, sizeof(t));
238
239 t[0].tx_buf = &cmd;
240 t[0].len = sizeof(cmd);
241 spi_message_add_tail(&t[0], &m);
242
243 t[1].tx_buf = buf;
244 t[1].len = count;
245 spi_message_add_tail(&t[1], &m);
246
247 mutex_lock(&ks->lock);
248 err = spi_sync(ks->spi, &m);
249 mutex_unlock(&ks->lock);
250
251 return err ? err : count;
252 }
253
ks8995_read_reg(struct ks8995_switch * ks,u8 addr,u8 * buf)254 static inline int ks8995_read_reg(struct ks8995_switch *ks, u8 addr, u8 *buf)
255 {
256 return ks8995_read(ks, buf, addr, 1) != 1;
257 }
258
ks8995_write_reg(struct ks8995_switch * ks,u8 addr,u8 val)259 static inline int ks8995_write_reg(struct ks8995_switch *ks, u8 addr, u8 val)
260 {
261 char buf = val;
262
263 return ks8995_write(ks, &buf, addr, 1) != 1;
264 }
265
266 /* ------------------------------------------------------------------------ */
267
ks8995_stop(struct ks8995_switch * ks)268 static int ks8995_stop(struct ks8995_switch *ks)
269 {
270 return ks8995_write_reg(ks, KS8995_REG_ID1, 0);
271 }
272
ks8995_start(struct ks8995_switch * ks)273 static int ks8995_start(struct ks8995_switch *ks)
274 {
275 return ks8995_write_reg(ks, KS8995_REG_ID1, 1);
276 }
277
ks8995_reset(struct ks8995_switch * ks)278 static int ks8995_reset(struct ks8995_switch *ks)
279 {
280 int err;
281
282 err = ks8995_stop(ks);
283 if (err)
284 return err;
285
286 udelay(KS8995_RESET_DELAY);
287
288 return ks8995_start(ks);
289 }
290
ks8995_registers_read(struct file * filp,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t off,size_t count)291 static ssize_t ks8995_registers_read(struct file *filp, struct kobject *kobj,
292 struct bin_attribute *bin_attr, char *buf, loff_t off, size_t count)
293 {
294 struct device *dev;
295 struct ks8995_switch *ks8995;
296
297 dev = kobj_to_dev(kobj);
298 ks8995 = dev_get_drvdata(dev);
299
300 return ks8995_read(ks8995, buf, off, count);
301 }
302
ks8995_registers_write(struct file * filp,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t off,size_t count)303 static ssize_t ks8995_registers_write(struct file *filp, struct kobject *kobj,
304 struct bin_attribute *bin_attr, char *buf, loff_t off, size_t count)
305 {
306 struct device *dev;
307 struct ks8995_switch *ks8995;
308
309 dev = kobj_to_dev(kobj);
310 ks8995 = dev_get_drvdata(dev);
311
312 return ks8995_write(ks8995, buf, off, count);
313 }
314
315 /* ks8995_get_revision - get chip revision
316 * @ks: pointer to switch instance
317 *
318 * Verify chip family and id and get chip revision.
319 */
ks8995_get_revision(struct ks8995_switch * ks)320 static int ks8995_get_revision(struct ks8995_switch *ks)
321 {
322 int err;
323 u8 id0, id1, ksz8864_id;
324
325 /* read family id */
326 err = ks8995_read_reg(ks, KS8995_REG_ID0, &id0);
327 if (err) {
328 err = -EIO;
329 goto err_out;
330 }
331
332 /* verify family id */
333 if (id0 != ks->chip->family_id) {
334 dev_err(&ks->spi->dev, "chip family id mismatch: expected 0x%02x but 0x%02x read\n",
335 ks->chip->family_id, id0);
336 err = -ENODEV;
337 goto err_out;
338 }
339
340 switch (ks->chip->family_id) {
341 case FAMILY_KS8995:
342 /* try reading chip id at CHIP ID1 */
343 err = ks8995_read_reg(ks, KS8995_REG_ID1, &id1);
344 if (err) {
345 err = -EIO;
346 goto err_out;
347 }
348
349 /* verify chip id */
350 if ((get_chip_id(id1) == CHIPID_M) &&
351 (get_chip_id(id1) == ks->chip->chip_id)) {
352 /* KS8995MA */
353 ks->revision_id = get_chip_rev(id1);
354 } else if (get_chip_id(id1) != CHIPID_M) {
355 /* KSZ8864RMN */
356 err = ks8995_read_reg(ks, KS8995_REG_ID1, &ksz8864_id);
357 if (err) {
358 err = -EIO;
359 goto err_out;
360 }
361
362 if ((ksz8864_id & 0x80) &&
363 (ks->chip->chip_id == KSZ8864_CHIP_ID)) {
364 ks->revision_id = get_chip_rev(id1);
365 }
366
367 } else {
368 dev_err(&ks->spi->dev, "unsupported chip id for KS8995 family: 0x%02x\n",
369 id1);
370 err = -ENODEV;
371 }
372 break;
373 case FAMILY_KSZ8795:
374 /* try reading chip id at CHIP ID1 */
375 err = ks8995_read_reg(ks, KS8995_REG_ID1, &id1);
376 if (err) {
377 err = -EIO;
378 goto err_out;
379 }
380
381 if (get_chip_id(id1) == ks->chip->chip_id) {
382 ks->revision_id = get_chip_rev(id1);
383 } else {
384 dev_err(&ks->spi->dev, "unsupported chip id for KSZ8795 family: 0x%02x\n",
385 id1);
386 err = -ENODEV;
387 }
388 break;
389 default:
390 dev_err(&ks->spi->dev, "unsupported family id: 0x%02x\n", id0);
391 err = -ENODEV;
392 break;
393 }
394 err_out:
395 return err;
396 }
397
398 static const struct bin_attribute ks8995_registers_attr = {
399 .attr = {
400 .name = "registers",
401 .mode = 0600,
402 },
403 .size = KS8995_REGS_SIZE,
404 .read = ks8995_registers_read,
405 .write = ks8995_registers_write,
406 };
407
408 /* ------------------------------------------------------------------------ */
ks8995_probe(struct spi_device * spi)409 static int ks8995_probe(struct spi_device *spi)
410 {
411 struct ks8995_switch *ks;
412 int err;
413 int variant = spi_get_device_id(spi)->driver_data;
414
415 if (variant >= max_variant) {
416 dev_err(&spi->dev, "bad chip variant %d\n", variant);
417 return -ENODEV;
418 }
419
420 ks = devm_kzalloc(&spi->dev, sizeof(*ks), GFP_KERNEL);
421 if (!ks)
422 return -ENOMEM;
423
424 mutex_init(&ks->lock);
425 ks->spi = spi;
426 ks->chip = &ks8995_chip[variant];
427
428 ks->reset_gpio = devm_gpiod_get_optional(&spi->dev, "reset",
429 GPIOD_OUT_HIGH);
430 err = PTR_ERR_OR_ZERO(ks->reset_gpio);
431 if (err) {
432 dev_err(&spi->dev,
433 "failed to get reset gpio: %d\n", err);
434 return err;
435 }
436
437 err = gpiod_set_consumer_name(ks->reset_gpio, "switch-reset");
438 if (err)
439 return err;
440
441 /* de-assert switch reset */
442 /* FIXME: this likely requires a delay */
443 gpiod_set_value_cansleep(ks->reset_gpio, 0);
444
445 spi_set_drvdata(spi, ks);
446
447 spi->mode = SPI_MODE_0;
448 spi->bits_per_word = 8;
449 err = spi_setup(spi);
450 if (err) {
451 dev_err(&spi->dev, "spi_setup failed, err=%d\n", err);
452 return err;
453 }
454
455 err = ks8995_get_revision(ks);
456 if (err)
457 return err;
458
459 memcpy(&ks->regs_attr, &ks8995_registers_attr, sizeof(ks->regs_attr));
460 ks->regs_attr.size = ks->chip->regs_size;
461
462 err = ks8995_reset(ks);
463 if (err)
464 return err;
465
466 sysfs_attr_init(&ks->regs_attr.attr);
467 err = sysfs_create_bin_file(&spi->dev.kobj, &ks->regs_attr);
468 if (err) {
469 dev_err(&spi->dev, "unable to create sysfs file, err=%d\n",
470 err);
471 return err;
472 }
473
474 dev_info(&spi->dev, "%s device found, Chip ID:%x, Revision:%x\n",
475 ks->chip->name, ks->chip->chip_id, ks->revision_id);
476
477 return 0;
478 }
479
ks8995_remove(struct spi_device * spi)480 static void ks8995_remove(struct spi_device *spi)
481 {
482 struct ks8995_switch *ks = spi_get_drvdata(spi);
483
484 sysfs_remove_bin_file(&spi->dev.kobj, &ks->regs_attr);
485
486 /* assert reset */
487 gpiod_set_value_cansleep(ks->reset_gpio, 1);
488 }
489
490 /* ------------------------------------------------------------------------ */
491 static struct spi_driver ks8995_driver = {
492 .driver = {
493 .name = "spi-ks8995",
494 .of_match_table = ks8895_spi_of_match,
495 },
496 .probe = ks8995_probe,
497 .remove = ks8995_remove,
498 .id_table = ks8995_id,
499 };
500
501 module_spi_driver(ks8995_driver);
502
503 MODULE_DESCRIPTION(DRV_DESC);
504 MODULE_VERSION(DRV_VERSION);
505 MODULE_AUTHOR("Gabor Juhos <juhosg at openwrt.org>");
506 MODULE_LICENSE("GPL v2");
507