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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#include <linux/of_gpio.h>
21
22#include <linux/spi/spi.h>
23
24#define DRV_VERSION "0.1.1"
25#define DRV_DESC "Micrel KS8995 Ethernet switch SPI driver"
26
27/* ------------------------------------------------------------------------ */
28
29#define KS8995_REG_ID0 0x00 /* Chip ID0 */
30#define KS8995_REG_ID1 0x01 /* Chip ID1 */
31
32#define KS8995_REG_GC0 0x02 /* Global Control 0 */
33#define KS8995_REG_GC1 0x03 /* Global Control 1 */
34#define KS8995_REG_GC2 0x04 /* Global Control 2 */
35#define KS8995_REG_GC3 0x05 /* Global Control 3 */
36#define KS8995_REG_GC4 0x06 /* Global Control 4 */
37#define KS8995_REG_GC5 0x07 /* Global Control 5 */
38#define KS8995_REG_GC6 0x08 /* Global Control 6 */
39#define KS8995_REG_GC7 0x09 /* Global Control 7 */
40#define KS8995_REG_GC8 0x0a /* Global Control 8 */
41#define KS8995_REG_GC9 0x0b /* Global Control 9 */
42
43#define KS8995_REG_PC(p, r) ((0x10 * p) + r) /* Port Control */
44#define KS8995_REG_PS(p, r) ((0x10 * p) + r + 0xe) /* Port Status */
45
46#define KS8995_REG_TPC0 0x60 /* TOS Priority Control 0 */
47#define KS8995_REG_TPC1 0x61 /* TOS Priority Control 1 */
48#define KS8995_REG_TPC2 0x62 /* TOS Priority Control 2 */
49#define KS8995_REG_TPC3 0x63 /* TOS Priority Control 3 */
50#define KS8995_REG_TPC4 0x64 /* TOS Priority Control 4 */
51#define KS8995_REG_TPC5 0x65 /* TOS Priority Control 5 */
52#define KS8995_REG_TPC6 0x66 /* TOS Priority Control 6 */
53#define KS8995_REG_TPC7 0x67 /* TOS Priority Control 7 */
54
55#define KS8995_REG_MAC0 0x68 /* MAC address 0 */
56#define KS8995_REG_MAC1 0x69 /* MAC address 1 */
57#define KS8995_REG_MAC2 0x6a /* MAC address 2 */
58#define KS8995_REG_MAC3 0x6b /* MAC address 3 */
59#define KS8995_REG_MAC4 0x6c /* MAC address 4 */
60#define KS8995_REG_MAC5 0x6d /* MAC address 5 */
61
62#define KS8995_REG_IAC0 0x6e /* Indirect Access Control 0 */
63#define KS8995_REG_IAC1 0x6f /* Indirect Access Control 0 */
64#define KS8995_REG_IAD7 0x70 /* Indirect Access Data 7 */
65#define KS8995_REG_IAD6 0x71 /* Indirect Access Data 6 */
66#define KS8995_REG_IAD5 0x72 /* Indirect Access Data 5 */
67#define KS8995_REG_IAD4 0x73 /* Indirect Access Data 4 */
68#define KS8995_REG_IAD3 0x74 /* Indirect Access Data 3 */
69#define KS8995_REG_IAD2 0x75 /* Indirect Access Data 2 */
70#define KS8995_REG_IAD1 0x76 /* Indirect Access Data 1 */
71#define KS8995_REG_IAD0 0x77 /* Indirect Access Data 0 */
72
73#define KSZ8864_REG_ID1 0xfe /* Chip ID in bit 7 */
74
75#define KS8995_REGS_SIZE 0x80
76#define KSZ8864_REGS_SIZE 0x100
77#define KSZ8795_REGS_SIZE 0x100
78
79#define ID1_CHIPID_M 0xf
80#define ID1_CHIPID_S 4
81#define ID1_REVISION_M 0x7
82#define ID1_REVISION_S 1
83#define ID1_START_SW 1 /* start the switch */
84
85#define FAMILY_KS8995 0x95
86#define FAMILY_KSZ8795 0x87
87#define CHIPID_M 0
88#define KS8995_CHIP_ID 0x00
89#define KSZ8864_CHIP_ID 0x01
90#define KSZ8795_CHIP_ID 0x09
91
92#define KS8995_CMD_WRITE 0x02U
93#define KS8995_CMD_READ 0x03U
94
95#define KS8995_RESET_DELAY 10 /* usec */
96
97enum ks8995_chip_variant {
98 ks8995,
99 ksz8864,
100 ksz8795,
101 max_variant
102};
103
104struct ks8995_chip_params {
105 char *name;
106 int family_id;
107 int chip_id;
108 int regs_size;
109 int addr_width;
110 int addr_shift;
111};
112
113static const struct ks8995_chip_params ks8995_chip[] = {
114 [ks8995] = {
115 .name = "KS8995MA",
116 .family_id = FAMILY_KS8995,
117 .chip_id = KS8995_CHIP_ID,
118 .regs_size = KS8995_REGS_SIZE,
119 .addr_width = 8,
120 .addr_shift = 0,
121 },
122 [ksz8864] = {
123 .name = "KSZ8864RMN",
124 .family_id = FAMILY_KS8995,
125 .chip_id = KSZ8864_CHIP_ID,
126 .regs_size = KSZ8864_REGS_SIZE,
127 .addr_width = 8,
128 .addr_shift = 0,
129 },
130 [ksz8795] = {
131 .name = "KSZ8795CLX",
132 .family_id = FAMILY_KSZ8795,
133 .chip_id = KSZ8795_CHIP_ID,
134 .regs_size = KSZ8795_REGS_SIZE,
135 .addr_width = 12,
136 .addr_shift = 1,
137 },
138};
139
140struct ks8995_pdata {
141 int reset_gpio;
142 enum of_gpio_flags reset_gpio_flags;
143};
144
145struct ks8995_switch {
146 struct spi_device *spi;
147 struct mutex lock;
148 struct ks8995_pdata *pdata;
149 struct bin_attribute regs_attr;
150 const struct ks8995_chip_params *chip;
151 int revision_id;
152};
153
154static const struct spi_device_id ks8995_id[] = {
155 {"ks8995", ks8995},
156 {"ksz8864", ksz8864},
157 {"ksz8795", ksz8795},
158 { }
159};
160MODULE_DEVICE_TABLE(spi, ks8995_id);
161
162static const struct of_device_id ks8895_spi_of_match[] = {
163 { .compatible = "micrel,ks8995" },
164 { .compatible = "micrel,ksz8864" },
165 { .compatible = "micrel,ksz8795" },
166 { },
167};
168MODULE_DEVICE_TABLE(of, ks8895_spi_of_match);
169
170static inline u8 get_chip_id(u8 val)
171{
172 return (val >> ID1_CHIPID_S) & ID1_CHIPID_M;
173}
174
175static inline u8 get_chip_rev(u8 val)
176{
177 return (val >> ID1_REVISION_S) & ID1_REVISION_M;
178}
179
180/* create_spi_cmd - create a chip specific SPI command header
181 * @ks: pointer to switch instance
182 * @cmd: SPI command for switch
183 * @address: register address for command
184 *
185 * Different chip families use different bit pattern to address the switches
186 * registers:
187 *
188 * KS8995: 8bit command + 8bit address
189 * KSZ8795: 3bit command + 12bit address + 1bit TR (?)
190 */
191static inline __be16 create_spi_cmd(struct ks8995_switch *ks, int cmd,
192 unsigned address)
193{
194 u16 result = cmd;
195
196 /* make room for address (incl. address shift) */
197 result <<= ks->chip->addr_width + ks->chip->addr_shift;
198 /* add address */
199 result |= address << ks->chip->addr_shift;
200 /* SPI protocol needs big endian */
201 return cpu_to_be16(result);
202}
203/* ------------------------------------------------------------------------ */
204static int ks8995_read(struct ks8995_switch *ks, char *buf,
205 unsigned offset, size_t count)
206{
207 __be16 cmd;
208 struct spi_transfer t[2];
209 struct spi_message m;
210 int err;
211
212 cmd = create_spi_cmd(ks, KS8995_CMD_READ, offset);
213 spi_message_init(&m);
214
215 memset(&t, 0, sizeof(t));
216
217 t[0].tx_buf = &cmd;
218 t[0].len = sizeof(cmd);
219 spi_message_add_tail(&t[0], &m);
220
221 t[1].rx_buf = buf;
222 t[1].len = count;
223 spi_message_add_tail(&t[1], &m);
224
225 mutex_lock(&ks->lock);
226 err = spi_sync(ks->spi, &m);
227 mutex_unlock(&ks->lock);
228
229 return err ? err : count;
230}
231
232static int ks8995_write(struct ks8995_switch *ks, char *buf,
233 unsigned offset, size_t count)
234{
235 __be16 cmd;
236 struct spi_transfer t[2];
237 struct spi_message m;
238 int err;
239
240 cmd = create_spi_cmd(ks, KS8995_CMD_WRITE, offset);
241 spi_message_init(&m);
242
243 memset(&t, 0, sizeof(t));
244
245 t[0].tx_buf = &cmd;
246 t[0].len = sizeof(cmd);
247 spi_message_add_tail(&t[0], &m);
248
249 t[1].tx_buf = buf;
250 t[1].len = count;
251 spi_message_add_tail(&t[1], &m);
252
253 mutex_lock(&ks->lock);
254 err = spi_sync(ks->spi, &m);
255 mutex_unlock(&ks->lock);
256
257 return err ? err : count;
258}
259
260static inline int ks8995_read_reg(struct ks8995_switch *ks, u8 addr, u8 *buf)
261{
262 return ks8995_read(ks, buf, addr, 1) != 1;
263}
264
265static inline int ks8995_write_reg(struct ks8995_switch *ks, u8 addr, u8 val)
266{
267 char buf = val;
268
269 return ks8995_write(ks, &buf, addr, 1) != 1;
270}
271
272/* ------------------------------------------------------------------------ */
273
274static int ks8995_stop(struct ks8995_switch *ks)
275{
276 return ks8995_write_reg(ks, KS8995_REG_ID1, 0);
277}
278
279static int ks8995_start(struct ks8995_switch *ks)
280{
281 return ks8995_write_reg(ks, KS8995_REG_ID1, 1);
282}
283
284static int ks8995_reset(struct ks8995_switch *ks)
285{
286 int err;
287
288 err = ks8995_stop(ks);
289 if (err)
290 return err;
291
292 udelay(KS8995_RESET_DELAY);
293
294 return ks8995_start(ks);
295}
296
297static ssize_t ks8995_registers_read(struct file *filp, struct kobject *kobj,
298 struct bin_attribute *bin_attr, char *buf, loff_t off, size_t count)
299{
300 struct device *dev;
301 struct ks8995_switch *ks8995;
302
303 dev = kobj_to_dev(kobj);
304 ks8995 = dev_get_drvdata(dev);
305
306 return ks8995_read(ks8995, buf, off, count);
307}
308
309static ssize_t ks8995_registers_write(struct file *filp, struct kobject *kobj,
310 struct bin_attribute *bin_attr, char *buf, loff_t off, size_t count)
311{
312 struct device *dev;
313 struct ks8995_switch *ks8995;
314
315 dev = kobj_to_dev(kobj);
316 ks8995 = dev_get_drvdata(dev);
317
318 return ks8995_write(ks8995, buf, off, count);
319}
320
321/* ks8995_get_revision - get chip revision
322 * @ks: pointer to switch instance
323 *
324 * Verify chip family and id and get chip revision.
325 */
326static int ks8995_get_revision(struct ks8995_switch *ks)
327{
328 int err;
329 u8 id0, id1, ksz8864_id;
330
331 /* read family id */
332 err = ks8995_read_reg(ks, KS8995_REG_ID0, &id0);
333 if (err) {
334 err = -EIO;
335 goto err_out;
336 }
337
338 /* verify family id */
339 if (id0 != ks->chip->family_id) {
340 dev_err(&ks->spi->dev, "chip family id mismatch: expected 0x%02x but 0x%02x read\n",
341 ks->chip->family_id, id0);
342 err = -ENODEV;
343 goto err_out;
344 }
345
346 switch (ks->chip->family_id) {
347 case FAMILY_KS8995:
348 /* try reading chip id at CHIP ID1 */
349 err = ks8995_read_reg(ks, KS8995_REG_ID1, &id1);
350 if (err) {
351 err = -EIO;
352 goto err_out;
353 }
354
355 /* verify chip id */
356 if ((get_chip_id(id1) == CHIPID_M) &&
357 (get_chip_id(id1) == ks->chip->chip_id)) {
358 /* KS8995MA */
359 ks->revision_id = get_chip_rev(id1);
360 } else if (get_chip_id(id1) != CHIPID_M) {
361 /* KSZ8864RMN */
362 err = ks8995_read_reg(ks, KS8995_REG_ID1, &ksz8864_id);
363 if (err) {
364 err = -EIO;
365 goto err_out;
366 }
367
368 if ((ksz8864_id & 0x80) &&
369 (ks->chip->chip_id == KSZ8864_CHIP_ID)) {
370 ks->revision_id = get_chip_rev(id1);
371 }
372
373 } else {
374 dev_err(&ks->spi->dev, "unsupported chip id for KS8995 family: 0x%02x\n",
375 id1);
376 err = -ENODEV;
377 }
378 break;
379 case FAMILY_KSZ8795:
380 /* try reading chip id at CHIP ID1 */
381 err = ks8995_read_reg(ks, KS8995_REG_ID1, &id1);
382 if (err) {
383 err = -EIO;
384 goto err_out;
385 }
386
387 if (get_chip_id(id1) == ks->chip->chip_id) {
388 ks->revision_id = get_chip_rev(id1);
389 } else {
390 dev_err(&ks->spi->dev, "unsupported chip id for KSZ8795 family: 0x%02x\n",
391 id1);
392 err = -ENODEV;
393 }
394 break;
395 default:
396 dev_err(&ks->spi->dev, "unsupported family id: 0x%02x\n", id0);
397 err = -ENODEV;
398 break;
399 }
400err_out:
401 return err;
402}
403
404/* ks8995_parse_dt - setup platform data from devicetree
405 * @ks: pointer to switch instance
406 *
407 * Parses supported DT properties and sets up platform data
408 * accordingly.
409 */
410static void ks8995_parse_dt(struct ks8995_switch *ks)
411{
412 struct device_node *np = ks->spi->dev.of_node;
413 struct ks8995_pdata *pdata = ks->pdata;
414
415 if (!np)
416 return;
417
418 pdata->reset_gpio = of_get_named_gpio_flags(np, "reset-gpios", 0,
419 &pdata->reset_gpio_flags);
420}
421
422static const struct bin_attribute ks8995_registers_attr = {
423 .attr = {
424 .name = "registers",
425 .mode = 0600,
426 },
427 .size = KS8995_REGS_SIZE,
428 .read = ks8995_registers_read,
429 .write = ks8995_registers_write,
430};
431
432/* ------------------------------------------------------------------------ */
433static int ks8995_probe(struct spi_device *spi)
434{
435 struct ks8995_switch *ks;
436 int err;
437 int variant = spi_get_device_id(spi)->driver_data;
438
439 if (variant >= max_variant) {
440 dev_err(&spi->dev, "bad chip variant %d\n", variant);
441 return -ENODEV;
442 }
443
444 ks = devm_kzalloc(&spi->dev, sizeof(*ks), GFP_KERNEL);
445 if (!ks)
446 return -ENOMEM;
447
448 mutex_init(&ks->lock);
449 ks->spi = spi;
450 ks->chip = &ks8995_chip[variant];
451
452 if (ks->spi->dev.of_node) {
453 ks->pdata = devm_kzalloc(&spi->dev, sizeof(*ks->pdata),
454 GFP_KERNEL);
455 if (!ks->pdata)
456 return -ENOMEM;
457
458 ks->pdata->reset_gpio = -1;
459
460 ks8995_parse_dt(ks);
461 }
462
463 if (!ks->pdata)
464 ks->pdata = spi->dev.platform_data;
465
466 /* de-assert switch reset */
467 if (ks->pdata && gpio_is_valid(ks->pdata->reset_gpio)) {
468 unsigned long flags;
469
470 flags = (ks->pdata->reset_gpio_flags == OF_GPIO_ACTIVE_LOW ?
471 GPIOF_ACTIVE_LOW : 0);
472
473 err = devm_gpio_request_one(&spi->dev,
474 ks->pdata->reset_gpio,
475 flags, "switch-reset");
476 if (err) {
477 dev_err(&spi->dev,
478 "failed to get reset-gpios: %d\n", err);
479 return -EIO;
480 }
481
482 gpiod_set_value(gpio_to_desc(ks->pdata->reset_gpio), 0);
483 }
484
485 spi_set_drvdata(spi, ks);
486
487 spi->mode = SPI_MODE_0;
488 spi->bits_per_word = 8;
489 err = spi_setup(spi);
490 if (err) {
491 dev_err(&spi->dev, "spi_setup failed, err=%d\n", err);
492 return err;
493 }
494
495 err = ks8995_get_revision(ks);
496 if (err)
497 return err;
498
499 memcpy(&ks->regs_attr, &ks8995_registers_attr, sizeof(ks->regs_attr));
500 ks->regs_attr.size = ks->chip->regs_size;
501
502 err = ks8995_reset(ks);
503 if (err)
504 return err;
505
506 sysfs_attr_init(&ks->regs_attr.attr);
507 err = sysfs_create_bin_file(&spi->dev.kobj, &ks->regs_attr);
508 if (err) {
509 dev_err(&spi->dev, "unable to create sysfs file, err=%d\n",
510 err);
511 return err;
512 }
513
514 dev_info(&spi->dev, "%s device found, Chip ID:%x, Revision:%x\n",
515 ks->chip->name, ks->chip->chip_id, ks->revision_id);
516
517 return 0;
518}
519
520static int ks8995_remove(struct spi_device *spi)
521{
522 struct ks8995_switch *ks = spi_get_drvdata(spi);
523
524 sysfs_remove_bin_file(&spi->dev.kobj, &ks->regs_attr);
525
526 /* assert reset */
527 if (ks->pdata && gpio_is_valid(ks->pdata->reset_gpio))
528 gpiod_set_value(gpio_to_desc(ks->pdata->reset_gpio), 1);
529
530 return 0;
531}
532
533/* ------------------------------------------------------------------------ */
534static struct spi_driver ks8995_driver = {
535 .driver = {
536 .name = "spi-ks8995",
537 .of_match_table = of_match_ptr(ks8895_spi_of_match),
538 },
539 .probe = ks8995_probe,
540 .remove = ks8995_remove,
541 .id_table = ks8995_id,
542};
543
544module_spi_driver(ks8995_driver);
545
546MODULE_DESCRIPTION(DRV_DESC);
547MODULE_VERSION(DRV_VERSION);
548MODULE_AUTHOR("Gabor Juhos <juhosg at openwrt.org>");
549MODULE_LICENSE("GPL v2");