summaryrefslogtreecommitdiffstats
path: root/drivers/net/dsa/realtek-smi.c
blob: b4b839a1d09521c521b340679592b3f36b5fb33f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
// SPDX-License-Identifier: GPL-2.0+
/* Realtek Simple Management Interface (SMI) driver
 * It can be discussed how "simple" this interface is.
 *
 * The SMI protocol piggy-backs the MDIO MDC and MDIO signals levels
 * but the protocol is not MDIO at all. Instead it is a Realtek
 * pecularity that need to bit-bang the lines in a special way to
 * communicate with the switch.
 *
 * ASICs we intend to support with this driver:
 *
 * RTL8366   - The original version, apparently
 * RTL8369   - Similar enough to have the same datsheet as RTL8366
 * RTL8366RB - Probably reads out "RTL8366 revision B", has a quite
 *             different register layout from the other two
 * RTL8366S  - Is this "RTL8366 super"?
 * RTL8367   - Has an OpenWRT driver as well
 * RTL8368S  - Seems to be an alternative name for RTL8366RB
 * RTL8370   - Also uses SMI
 *
 * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
 * Copyright (C) 2010 Antti Seppälä <a.seppala@gmail.com>
 * Copyright (C) 2010 Roman Yeryomin <roman@advem.lv>
 * Copyright (C) 2011 Colin Leitner <colin.leitner@googlemail.com>
 * Copyright (C) 2009-2010 Gabor Juhos <juhosg@openwrt.org>
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/spinlock.h>
#include <linux/skbuff.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_mdio.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/bitops.h>
#include <linux/if_bridge.h>

#include "realtek-smi.h"

#define REALTEK_SMI_ACK_RETRY_COUNT		5
#define REALTEK_SMI_HW_STOP_DELAY		25	/* msecs */
#define REALTEK_SMI_HW_START_DELAY		100	/* msecs */

static inline void realtek_smi_clk_delay(struct realtek_smi *smi)
{
	ndelay(smi->clk_delay);
}

static void realtek_smi_start(struct realtek_smi *smi)
{
	/* Set GPIO pins to output mode, with initial state:
	 * SCK = 0, SDA = 1
	 */
	gpiod_direction_output(smi->mdc, 0);
	gpiod_direction_output(smi->mdio, 1);
	realtek_smi_clk_delay(smi);

	/* CLK 1: 0 -> 1, 1 -> 0 */
	gpiod_set_value(smi->mdc, 1);
	realtek_smi_clk_delay(smi);
	gpiod_set_value(smi->mdc, 0);
	realtek_smi_clk_delay(smi);

	/* CLK 2: */
	gpiod_set_value(smi->mdc, 1);
	realtek_smi_clk_delay(smi);
	gpiod_set_value(smi->mdio, 0);
	realtek_smi_clk_delay(smi);
	gpiod_set_value(smi->mdc, 0);
	realtek_smi_clk_delay(smi);
	gpiod_set_value(smi->mdio, 1);
}

static void realtek_smi_stop(struct realtek_smi *smi)
{
	realtek_smi_clk_delay(smi);
	gpiod_set_value(smi->mdio, 0);
	gpiod_set_value(smi->mdc, 1);
	realtek_smi_clk_delay(smi);
	gpiod_set_value(smi->mdio, 1);
	realtek_smi_clk_delay(smi);
	gpiod_set_value(smi->mdc, 1);
	realtek_smi_clk_delay(smi);
	gpiod_set_value(smi->mdc, 0);
	realtek_smi_clk_delay(smi);
	gpiod_set_value(smi->mdc, 1);

	/* Add a click */
	realtek_smi_clk_delay(smi);
	gpiod_set_value(smi->mdc, 0);
	realtek_smi_clk_delay(smi);
	gpiod_set_value(smi->mdc, 1);

	/* Set GPIO pins to input mode */
	gpiod_direction_input(smi->mdio);
	gpiod_direction_input(smi->mdc);
}

static void realtek_smi_write_bits(struct realtek_smi *smi, u32 data, u32 len)
{
	for (; len > 0; len--) {
		realtek_smi_clk_delay(smi);

		/* Prepare data */
		gpiod_set_value(smi->mdio, !!(data & (1 << (len - 1))));
		realtek_smi_clk_delay(smi);

		/* Clocking */
		gpiod_set_value(smi->mdc, 1);
		realtek_smi_clk_delay(smi);
		gpiod_set_value(smi->mdc, 0);
	}
}

static void realtek_smi_read_bits(struct realtek_smi *smi, u32 len, u32 *data)
{
	gpiod_direction_input(smi->mdio);

	for (*data = 0; len > 0; len--) {
		u32 u;

		realtek_smi_clk_delay(smi);

		/* Clocking */
		gpiod_set_value(smi->mdc, 1);
		realtek_smi_clk_delay(smi);
		u = !!gpiod_get_value(smi->mdio);
		gpiod_set_value(smi->mdc, 0);

		*data |= (u << (len - 1));
	}

	gpiod_direction_output(smi->mdio, 0);
}

static int realtek_smi_wait_for_ack(struct realtek_smi *smi)
{
	int retry_cnt;

	retry_cnt = 0;
	do {
		u32 ack;

		realtek_smi_read_bits(smi, 1, &ack);
		if (ack == 0)
			break;

		if (++retry_cnt > REALTEK_SMI_ACK_RETRY_COUNT) {
			dev_err(smi->dev, "ACK timeout\n");
			return -ETIMEDOUT;
		}
	} while (1);

	return 0;
}

static int realtek_smi_write_byte(struct realtek_smi *smi, u8 data)
{
	realtek_smi_write_bits(smi, data, 8);
	return realtek_smi_wait_for_ack(smi);
}

static int realtek_smi_write_byte_noack(struct realtek_smi *smi, u8 data)
{
	realtek_smi_write_bits(smi, data, 8);
	return 0;
}

static int realtek_smi_read_byte0(struct realtek_smi *smi, u8 *data)
{
	u32 t;

	/* Read data */
	realtek_smi_read_bits(smi, 8, &t);
	*data = (t & 0xff);

	/* Send an ACK */
	realtek_smi_write_bits(smi, 0x00, 1);

	return 0;
}

static int realtek_smi_read_byte1(struct realtek_smi *smi, u8 *data)
{
	u32 t;

	/* Read data */
	realtek_smi_read_bits(smi, 8, &t);
	*data = (t & 0xff);

	/* Send an ACK */
	realtek_smi_write_bits(smi, 0x01, 1);

	return 0;
}

static int realtek_smi_read_reg(struct realtek_smi *smi, u32 addr, u32 *data)
{
	unsigned long flags;
	u8 lo = 0;
	u8 hi = 0;
	int ret;

	spin_lock_irqsave(&smi->lock, flags);

	realtek_smi_start(smi);

	/* Send READ command */
	ret = realtek_smi_write_byte(smi, smi->cmd_read);
	if (ret)
		goto out;

	/* Set ADDR[7:0] */
	ret = realtek_smi_write_byte(smi, addr & 0xff);
	if (ret)
		goto out;

	/* Set ADDR[15:8] */
	ret = realtek_smi_write_byte(smi, addr >> 8);
	if (ret)
		goto out;

	/* Read DATA[7:0] */
	realtek_smi_read_byte0(smi, &lo);
	/* Read DATA[15:8] */
	realtek_smi_read_byte1(smi, &hi);

	*data = ((u32)lo) | (((u32)hi) << 8);

	ret = 0;

 out:
	realtek_smi_stop(smi);
	spin_unlock_irqrestore(&smi->lock, flags);

	return ret;
}

static int realtek_smi_write_reg(struct realtek_smi *smi,
				 u32 addr, u32 data, bool ack)
{
	unsigned long flags;
	int ret;

	spin_lock_irqsave(&smi->lock, flags);

	realtek_smi_start(smi);

	/* Send WRITE command */
	ret = realtek_smi_write_byte(smi, smi->cmd_write);
	if (ret)
		goto out;

	/* Set ADDR[7:0] */
	ret = realtek_smi_write_byte(smi, addr & 0xff);
	if (ret)
		goto out;

	/* Set ADDR[15:8] */
	ret = realtek_smi_write_byte(smi, addr >> 8);
	if (ret)
		goto out;

	/* Write DATA[7:0] */
	ret = realtek_smi_write_byte(smi, data & 0xff);
	if (ret)
		goto out;

	/* Write DATA[15:8] */
	if (ack)
		ret = realtek_smi_write_byte(smi, data >> 8);
	else
		ret = realtek_smi_write_byte_noack(smi, data >> 8);
	if (ret)
		goto out;

	ret = 0;

 out:
	realtek_smi_stop(smi);
	spin_unlock_irqrestore(&smi->lock, flags);

	return ret;
}

/* There is one single case when we need to use this accessor and that
 * is when issueing soft reset. Since the device reset as soon as we write
 * that bit, no ACK will come back for natural reasons.
 */
int realtek_smi_write_reg_noack(struct realtek_smi *smi, u32 addr,
				u32 data)
{
	return realtek_smi_write_reg(smi, addr, data, false);
}
EXPORT_SYMBOL_GPL(realtek_smi_write_reg_noack);

/* Regmap accessors */

static int realtek_smi_write(void *ctx, u32 reg, u32 val)
{
	struct realtek_smi *smi = ctx;

	return realtek_smi_write_reg(smi, reg, val, true);
}

static int realtek_smi_read(void *ctx, u32 reg, u32 *val)
{
	struct realtek_smi *smi = ctx;

	return realtek_smi_read_reg(smi, reg, val);
}

static const struct regmap_config realtek_smi_mdio_regmap_config = {
	.reg_bits = 10, /* A4..A0 R4..R0 */
	.val_bits = 16,
	.reg_stride = 1,
	/* PHY regs are at 0x8000 */
	.max_register = 0xffff,
	.reg_format_endian = REGMAP_ENDIAN_BIG,
	.reg_read = realtek_smi_read,
	.reg_write = realtek_smi_write,
	.cache_type = REGCACHE_NONE,
};

static int realtek_smi_mdio_read(struct mii_bus *bus, int addr, int regnum)
{
	struct realtek_smi *smi = bus->priv;

	return smi->ops->phy_read(smi, addr, regnum);
}

static int realtek_smi_mdio_write(struct mii_bus *bus, int addr, int regnum,
				  u16 val)
{
	struct realtek_smi *smi = bus->priv;

	return smi->ops->phy_write(smi, addr, regnum, val);
}

int realtek_smi_setup_mdio(struct realtek_smi *smi)
{
	struct device_node *mdio_np;
	int ret;

	mdio_np = of_find_compatible_node(smi->dev->of_node, NULL,
					  "realtek,smi-mdio");
	if (!mdio_np) {
		dev_err(smi->dev, "no MDIO bus node\n");
		return -ENODEV;
	}

	smi->slave_mii_bus = devm_mdiobus_alloc(smi->dev);
	if (!smi->slave_mii_bus)
		return -ENOMEM;
	smi->slave_mii_bus->priv = smi;
	smi->slave_mii_bus->name = "SMI slave MII";
	smi->slave_mii_bus->read = realtek_smi_mdio_read;
	smi->slave_mii_bus->write = realtek_smi_mdio_write;
	snprintf(smi->slave_mii_bus->id, MII_BUS_ID_SIZE, "SMI-%d",
		 smi->ds->index);
	smi->slave_mii_bus->dev.of_node = mdio_np;
	smi->slave_mii_bus->parent = smi->dev;
	smi->ds->slave_mii_bus = smi->slave_mii_bus;

	ret = of_mdiobus_register(smi->slave_mii_bus, mdio_np);
	if (ret) {
		dev_err(smi->dev, "unable to register MDIO bus %s\n",
			smi->slave_mii_bus->id);
		of_node_put(mdio_np);
	}

	return 0;
}

static int realtek_smi_probe(struct platform_device *pdev)
{
	const struct realtek_smi_variant *var;
	struct device *dev = &pdev->dev;
	struct realtek_smi *smi;
	struct device_node *np;
	int ret;

	var = of_device_get_match_data(dev);
	np = dev->of_node;

	smi = devm_kzalloc(dev, sizeof(*smi), GFP_KERNEL);
	if (!smi)
		return -ENOMEM;
	smi->map = devm_regmap_init(dev, NULL, smi,
				    &realtek_smi_mdio_regmap_config);
	if (IS_ERR(smi->map)) {
		ret = PTR_ERR(smi->map);
		dev_err(dev, "regmap init failed: %d\n", ret);
		return ret;
	}

	/* Link forward and backward */
	smi->dev = dev;
	smi->clk_delay = var->clk_delay;
	smi->cmd_read = var->cmd_read;
	smi->cmd_write = var->cmd_write;
	smi->ops = var->ops;

	dev_set_drvdata(dev, smi);
	spin_lock_init(&smi->lock);

	/* TODO: if power is software controlled, set up any regulators here */

	/* Assert then deassert RESET */
	smi->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
	if (IS_ERR(smi->reset)) {
		dev_err(dev, "failed to get RESET GPIO\n");
		return PTR_ERR(smi->reset);
	}
	msleep(REALTEK_SMI_HW_STOP_DELAY);
	gpiod_set_value(smi->reset, 0);
	msleep(REALTEK_SMI_HW_START_DELAY);
	dev_info(dev, "deasserted RESET\n");

	/* Fetch MDIO pins */
	smi->mdc = devm_gpiod_get_optional(dev, "mdc", GPIOD_OUT_LOW);
	if (IS_ERR(smi->mdc))
		return PTR_ERR(smi->mdc);
	smi->mdio = devm_gpiod_get_optional(dev, "mdio", GPIOD_OUT_LOW);
	if (IS_ERR(smi->mdio))
		return PTR_ERR(smi->mdio);

	smi->leds_disabled = of_property_read_bool(np, "realtek,disable-leds");

	ret = smi->ops->detect(smi);
	if (ret) {
		dev_err(dev, "unable to detect switch\n");
		return ret;
	}

	smi->ds = dsa_switch_alloc(dev, smi->num_ports);
	if (!smi->ds)
		return -ENOMEM;
	smi->ds->priv = smi;

	smi->ds->ops = var->ds_ops;
	ret = dsa_register_switch(smi->ds);
	if (ret) {
		dev_err(dev, "unable to register switch ret = %d\n", ret);
		return ret;
	}
	return 0;
}

static int realtek_smi_remove(struct platform_device *pdev)
{
	struct realtek_smi *smi = dev_get_drvdata(&pdev->dev);

	dsa_unregister_switch(smi->ds);
	gpiod_set_value(smi->reset, 1);

	return 0;
}

static const struct of_device_id realtek_smi_of_match[] = {
	{
		.compatible = "realtek,rtl8366rb",
		.data = &rtl8366rb_variant,
	},
	{
		/* FIXME: add support for RTL8366S and more */
		.compatible = "realtek,rtl8366s",
		.data = NULL,
	},
	{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, realtek_smi_of_match);

static struct platform_driver realtek_smi_driver = {
	.driver = {
		.name = "realtek-smi",
		.of_match_table = of_match_ptr(realtek_smi_of_match),
	},
	.probe  = realtek_smi_probe,
	.remove = realtek_smi_remove,
};
module_platform_driver(realtek_smi_driver);

MODULE_LICENSE("GPL");