aboutsummaryrefslogtreecommitdiff
path: root/arch/powerpc/platforms/pasemi/gpio_mdio.c
blob: 75cc165d5bee6e73f0a07dc38edd60dcf442941d (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
/*
 * Copyright (C) 2006-2007 PA Semi, Inc
 *
 * Author: Olof Johansson, PA Semi
 *
 * Maintained by: Olof Johansson <olof@lixom.net>
 *
 * Based on drivers/net/fs_enet/mii-bitbang.c.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */

#include <linux/io.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/phy.h>
#include <linux/platform_device.h>
#include <linux/of_platform.h>

#define DELAY 1

static void __iomem *gpio_regs;

struct gpio_priv {
	int mdc_pin;
	int mdio_pin;
};

#define MDC_PIN(bus)	(((struct gpio_priv *)bus->priv)->mdc_pin)
#define MDIO_PIN(bus)	(((struct gpio_priv *)bus->priv)->mdio_pin)

static inline void mdio_lo(struct mii_bus *bus)
{
	out_le32(gpio_regs+0x10, 1 << MDIO_PIN(bus));
}

static inline void mdio_hi(struct mii_bus *bus)
{
	out_le32(gpio_regs, 1 << MDIO_PIN(bus));
}

static inline void mdc_lo(struct mii_bus *bus)
{
	out_le32(gpio_regs+0x10, 1 << MDC_PIN(bus));
}

static inline void mdc_hi(struct mii_bus *bus)
{
	out_le32(gpio_regs, 1 << MDC_PIN(bus));
}

static inline void mdio_active(struct mii_bus *bus)
{
	out_le32(gpio_regs+0x20, (1 << MDC_PIN(bus)) | (1 << MDIO_PIN(bus)));
}

static inline void mdio_tristate(struct mii_bus *bus)
{
	out_le32(gpio_regs+0x30, (1 << MDIO_PIN(bus)));
}

static inline int mdio_read(struct mii_bus *bus)
{
	return !!(in_le32(gpio_regs+0x40) & (1 << MDIO_PIN(bus)));
}

static void clock_out(struct mii_bus *bus, int bit)
{
	if (bit)
		mdio_hi(bus);
	else
		mdio_lo(bus);
	udelay(DELAY);
	mdc_hi(bus);
	udelay(DELAY);
	mdc_lo(bus);
}

/* Utility to send the preamble, address, and register (common to read and write). */
static void bitbang_pre(struct mii_bus *bus, int read, u8 addr, u8 reg)
{
	int i;

	/* CFE uses a really long preamble (40 bits). We'll do the same. */
	mdio_active(bus);
	for (i = 0; i < 40; i++) {
		clock_out(bus, 1);
	}

	/* send the start bit (01) and the read opcode (10) or write (10) */
	clock_out(bus, 0);
	clock_out(bus, 1);

	clock_out(bus, read);
	clock_out(bus, !read);

	/* send the PHY address */
	for (i = 0; i < 5; i++) {
		clock_out(bus, (addr & 0x10) != 0);
		addr <<= 1;
	}

	/* send the register address */
	for (i = 0; i < 5; i++) {
		clock_out(bus, (reg & 0x10) != 0);
		reg <<= 1;
	}
}

static int gpio_mdio_read(struct mii_bus *bus, int phy_id, int location)
{
	u16 rdreg;
	int ret, i;
	u8 addr = phy_id & 0xff;
	u8 reg = location & 0xff;

	bitbang_pre(bus, 1, addr, reg);

	/* tri-state our MDIO I/O pin so we can read */
	mdio_tristate(bus);
	udelay(DELAY);
	mdc_hi(bus);
	udelay(DELAY);
	mdc_lo(bus);

	/* read 16 bits of register data, MSB first */
	rdreg = 0;
	for (i = 0; i < 16; i++) {
		mdc_lo(bus);
		udelay(DELAY);
		mdc_hi(bus);
		udelay(DELAY);
		mdc_lo(bus);
		udelay(DELAY);
		rdreg <<= 1;
		rdreg |= mdio_read(bus);
	}

	mdc_hi(bus);
	udelay(DELAY);
	mdc_lo(bus);
	udelay(DELAY);

	ret = rdreg;

	return ret;
}

static int gpio_mdio_write(struct mii_bus *bus, int phy_id, int location, u16 val)
{
	int i;

	u8 addr = phy_id & 0xff;
	u8 reg = location & 0xff;
	u16 value = val & 0xffff;

	bitbang_pre(bus, 0, addr, reg);

	/* send the turnaround (10) */
	mdc_lo(bus);
	mdio_hi(bus);
	udelay(DELAY);
	mdc_hi(bus);
	udelay(DELAY);
	mdc_lo(bus);
	mdio_lo(bus);
	udelay(DELAY);
	mdc_hi(bus);
	udelay(DELAY);

	/* write 16 bits of register data, MSB first */
	for (i = 0; i < 16; i++) {
		mdc_lo(bus);
		if (value & 0x8000)
			mdio_hi(bus);
		else
			mdio_lo(bus);
		udelay(DELAY);
		mdc_hi(bus);
		udelay(DELAY);
		value <<= 1;
	}

	/*
	 * Tri-state the MDIO line.
	 */
	mdio_tristate(bus);
	mdc_lo(bus);
	udelay(DELAY);
	mdc_hi(bus);
	udelay(DELAY);
	return 0;
}

static int gpio_mdio_reset(struct mii_bus *bus)
{
	/*nothing here - dunno how to reset it*/
	return 0;
}


static int __devinit gpio_mdio_probe(struct of_device *ofdev,
				     const struct of_device_id *match)
{
	struct device *dev = &ofdev->dev;
	struct device_node *phy_dn, *np = ofdev->node;
	struct mii_bus *new_bus;
	struct gpio_priv *priv;
	const unsigned int *prop;
	int err;
	int i;

	err = -ENOMEM;
	priv = kzalloc(sizeof(struct gpio_priv), GFP_KERNEL);
	if (!priv)
		goto out;

	new_bus = mdiobus_alloc();

	if (!new_bus)
		goto out_free_priv;

	new_bus->name = "pasemi gpio mdio bus";
	new_bus->read = &gpio_mdio_read;
	new_bus->write = &gpio_mdio_write;
	new_bus->reset = &gpio_mdio_reset;

	prop = of_get_property(np, "reg", NULL);
	snprintf(new_bus->id, MII_BUS_ID_SIZE, "%x", *prop);
	new_bus->priv = priv;

	new_bus->phy_mask = 0;

	new_bus->irq = kmalloc(sizeof(int)*PHY_MAX_ADDR, GFP_KERNEL);

	if (!new_bus->irq)
		goto out_free_bus;

	for (i = 0; i < PHY_MAX_ADDR; i++)
		new_bus->irq[i] = NO_IRQ;

	for (phy_dn = of_get_next_child(np, NULL);
	     phy_dn != NULL;
	     phy_dn = of_get_next_child(np, phy_dn)) {
		const unsigned int *ip, *regp;

		ip = of_get_property(phy_dn, "interrupts", NULL);
		regp = of_get_property(phy_dn, "reg", NULL);
		if (!ip || !regp || *regp >= PHY_MAX_ADDR)
			continue;
		new_bus->irq[*regp] = irq_create_mapping(NULL, *ip);
	}

	prop = of_get_property(np, "mdc-pin", NULL);
	priv->mdc_pin = *prop;

	prop = of_get_property(np, "mdio-pin", NULL);
	priv->mdio_pin = *prop;

	new_bus->parent = dev;
	dev_set_drvdata(dev, new_bus);

	err = mdiobus_register(new_bus);

	if (err != 0) {
		printk(KERN_ERR "%s: Cannot register as MDIO bus, err %d\n",
				new_bus->name, err);
		goto out_free_irq;
	}

	return 0;

out_free_irq:
	kfree(new_bus->irq);
out_free_bus:
	kfree(new_bus);
out_free_priv:
	kfree(priv);
out:
	return err;
}


static int gpio_mdio_remove(struct of_device *dev)
{
	struct mii_bus *bus = dev_get_drvdata(&dev->dev);

	mdiobus_unregister(bus);

	dev_set_drvdata(&dev->dev, NULL);

	kfree(bus->priv);
	bus->priv = NULL;
	mdiobus_free(bus);

	return 0;
}

static struct of_device_id gpio_mdio_match[] =
{
	{
		.compatible      = "gpio-mdio",
	},
	{},
};
MODULE_DEVICE_TABLE(of, gpio_mdio_match);

static struct of_platform_driver gpio_mdio_driver =
{
	.match_table	= gpio_mdio_match,
	.probe		= gpio_mdio_probe,
	.remove		= gpio_mdio_remove,
	.driver		= {
		.name	= "gpio-mdio-bitbang",
	},
};

int gpio_mdio_init(void)
{
	struct device_node *np;

	np = of_find_compatible_node(NULL, NULL, "1682m-gpio");
	if (!np)
		np = of_find_compatible_node(NULL, NULL,
					     "pasemi,pwrficient-gpio");
	if (!np)
		return -ENODEV;
	gpio_regs = of_iomap(np, 0);
	of_node_put(np);

	if (!gpio_regs)
		return -ENODEV;

	return of_register_platform_driver(&gpio_mdio_driver);
}
module_init(gpio_mdio_init);

void gpio_mdio_exit(void)
{
	of_unregister_platform_driver(&gpio_mdio_driver);
	if (gpio_regs)
		iounmap(gpio_regs);
}
module_exit(gpio_mdio_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Olof Johansson <olof@lixom.net>");
MODULE_DESCRIPTION("Driver for MDIO over GPIO on PA Semi PWRficient-based boards");