aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/nfc/fdp/i2c.c
blob: 8a66b1845f270a1273e4c8e3cff742756ebc6246 (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
/* -------------------------------------------------------------------------
 * Copyright (C) 2014-2016, Intel Corporation
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  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.
 * -------------------------------------------------------------------------
 */

#include <linux/module.h>
#include <linux/acpi.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/nfc.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <net/nfc/nfc.h>
#include <net/nfc/nci_core.h>

#include "fdp.h"

#define FDP_I2C_DRIVER_NAME	"fdp_nci_i2c"

#define FDP_DP_POWER_GPIO_NAME	"power"
#define FDP_DP_CLOCK_TYPE_NAME	"clock-type"
#define FDP_DP_CLOCK_FREQ_NAME	"clock-freq"
#define FDP_DP_FW_VSC_CFG_NAME	"fw-vsc-cfg"

#define FDP_FRAME_HEADROOM	2
#define FDP_FRAME_TAILROOM	1

#define FDP_NCI_I2C_MIN_PAYLOAD	5
#define FDP_NCI_I2C_MAX_PAYLOAD	261

#define FDP_POWER_OFF		0
#define FDP_POWER_ON		1

#define fdp_nci_i2c_dump_skb(dev, prefix, skb)				\
	print_hex_dump(KERN_DEBUG, prefix": ", DUMP_PREFIX_OFFSET,	\
		       16, 1, (skb)->data, (skb)->len, 0)

static void fdp_nci_i2c_reset(struct fdp_i2c_phy *phy)
{
	/* Reset RST/WakeUP for at least 100 micro-second */
	gpiod_set_value_cansleep(phy->power_gpio, FDP_POWER_OFF);
	usleep_range(1000, 4000);
	gpiod_set_value_cansleep(phy->power_gpio, FDP_POWER_ON);
	usleep_range(10000, 14000);
}

static int fdp_nci_i2c_enable(void *phy_id)
{
	struct fdp_i2c_phy *phy = phy_id;

	dev_dbg(&phy->i2c_dev->dev, "%s\n", __func__);
	fdp_nci_i2c_reset(phy);

	return 0;
}

static void fdp_nci_i2c_disable(void *phy_id)
{
	struct fdp_i2c_phy *phy = phy_id;

	dev_dbg(&phy->i2c_dev->dev, "%s\n", __func__);
	fdp_nci_i2c_reset(phy);
}

static void fdp_nci_i2c_add_len_lrc(struct sk_buff *skb)
{
	u8 lrc = 0;
	u16 len, i;

	/* Add length header */
	len = skb->len;
	*(u8 *)skb_push(skb, 1) = len & 0xff;
	*(u8 *)skb_push(skb, 1) = len >> 8;

	/* Compute and add lrc */
	for (i = 0; i < len + 2; i++)
		lrc ^= skb->data[i];

	skb_put_u8(skb, lrc);
}

static void fdp_nci_i2c_remove_len_lrc(struct sk_buff *skb)
{
	skb_pull(skb, FDP_FRAME_HEADROOM);
	skb_trim(skb, skb->len - FDP_FRAME_TAILROOM);
}

static int fdp_nci_i2c_write(void *phy_id, struct sk_buff *skb)
{
	struct fdp_i2c_phy *phy = phy_id;
	struct i2c_client *client = phy->i2c_dev;
	int r;

	if (phy->hard_fault != 0)
		return phy->hard_fault;

	fdp_nci_i2c_add_len_lrc(skb);
	fdp_nci_i2c_dump_skb(&client->dev, "fdp_wr", skb);

	r = i2c_master_send(client, skb->data, skb->len);
	if (r == -EREMOTEIO) {  /* Retry, chip was in standby */
		usleep_range(1000, 4000);
		r = i2c_master_send(client, skb->data, skb->len);
	}

	if (r < 0 || r != skb->len)
		dev_dbg(&client->dev, "%s: error err=%d len=%d\n",
			__func__, r, skb->len);

	if (r >= 0) {
		if (r != skb->len) {
			phy->hard_fault = r;
			r = -EREMOTEIO;
		} else {
			r = 0;
		}
	}

	fdp_nci_i2c_remove_len_lrc(skb);

	return r;
}

static struct nfc_phy_ops i2c_phy_ops = {
	.write = fdp_nci_i2c_write,
	.enable = fdp_nci_i2c_enable,
	.disable = fdp_nci_i2c_disable,
};

static int fdp_nci_i2c_read(struct fdp_i2c_phy *phy, struct sk_buff **skb)
{
	int r, len;
	u8 tmp[FDP_NCI_I2C_MAX_PAYLOAD], lrc, k;
	u16 i;
	struct i2c_client *client = phy->i2c_dev;

	*skb = NULL;

	/* Read the length packet and the data packet */
	for (k = 0; k < 2; k++) {

		len = phy->next_read_size;

		r = i2c_master_recv(client, tmp, len);
		if (r != len) {
			dev_dbg(&client->dev, "%s: i2c recv err: %d\n",
				__func__, r);
			goto flush;
		}

		/* Check packet integruty */
		for (lrc = i = 0; i < r; i++)
			lrc ^= tmp[i];

		/*
		 * LRC check failed. This may due to transmission error or
		 * desynchronization between driver and FDP. Drop the paquet
		 * and force resynchronization
		 */
		if (lrc) {
			dev_dbg(&client->dev, "%s: corrupted packet\n",
				__func__);
			phy->next_read_size = 5;
			goto flush;
		}

		/* Packet that contains a length */
		if (tmp[0] == 0 && tmp[1] == 0) {
			phy->next_read_size = (tmp[2] << 8) + tmp[3] + 3;
		} else {
			phy->next_read_size = FDP_NCI_I2C_MIN_PAYLOAD;

			*skb = alloc_skb(len, GFP_KERNEL);
			if (*skb == NULL) {
				r = -ENOMEM;
				goto flush;
			}

			skb_put_data(*skb, tmp, len);
			fdp_nci_i2c_dump_skb(&client->dev, "fdp_rd", *skb);

			fdp_nci_i2c_remove_len_lrc(*skb);
		}
	}

	return 0;

flush:
	/* Flush the remaining data */
	if (i2c_master_recv(client, tmp, sizeof(tmp)) < 0)
		r = -EREMOTEIO;

	return r;
}

static irqreturn_t fdp_nci_i2c_irq_thread_fn(int irq, void *phy_id)
{
	struct fdp_i2c_phy *phy = phy_id;
	struct i2c_client *client;
	struct sk_buff *skb;
	int r;

	if (!phy || irq != phy->i2c_dev->irq) {
		WARN_ON_ONCE(1);
		return IRQ_NONE;
	}

	client = phy->i2c_dev;
	dev_dbg(&client->dev, "%s\n", __func__);

	r = fdp_nci_i2c_read(phy, &skb);

	if (r == -EREMOTEIO)
		return IRQ_HANDLED;
	else if (r == -ENOMEM || r == -EBADMSG)
		return IRQ_HANDLED;

	if (skb != NULL)
		fdp_nci_recv_frame(phy->ndev, skb);

	return IRQ_HANDLED;
}

static void fdp_nci_i2c_read_device_properties(struct device *dev,
					       u8 *clock_type, u32 *clock_freq,
					       u8 **fw_vsc_cfg)
{
	int r;
	u8 len;

	r = device_property_read_u8(dev, FDP_DP_CLOCK_TYPE_NAME, clock_type);
	if (r) {
		dev_dbg(dev, "Using default clock type");
		*clock_type = 0;
	}

	r = device_property_read_u32(dev, FDP_DP_CLOCK_FREQ_NAME, clock_freq);
	if (r) {
		dev_dbg(dev, "Using default clock frequency\n");
		*clock_freq = 26000;
	}

	if (device_property_present(dev, FDP_DP_FW_VSC_CFG_NAME)) {
		r = device_property_read_u8(dev, FDP_DP_FW_VSC_CFG_NAME,
					    &len);

		if (r || len <= 0)
			goto vsc_read_err;

		/* Add 1 to the length to inclue the length byte itself */
		len++;

		*fw_vsc_cfg = devm_kmalloc(dev,
					   len * sizeof(**fw_vsc_cfg),
					   GFP_KERNEL);

		r = device_property_read_u8_array(dev, FDP_DP_FW_VSC_CFG_NAME,
						  *fw_vsc_cfg, len);

		if (r) {
			devm_kfree(dev, fw_vsc_cfg);
			goto vsc_read_err;
		}
	} else {
vsc_read_err:
		dev_dbg(dev, "FW vendor specific commands not present\n");
		*fw_vsc_cfg = NULL;
	}

	dev_dbg(dev, "Clock type: %d, clock frequency: %d, VSC: %s",
		*clock_type, *clock_freq, *fw_vsc_cfg != NULL ? "yes" : "no");
}

static int fdp_nci_i2c_probe(struct i2c_client *client)
{
	struct fdp_i2c_phy *phy;
	struct device *dev = &client->dev;
	u8 *fw_vsc_cfg;
	u8 clock_type;
	u32 clock_freq;
	int r = 0;

	dev_dbg(dev, "%s\n", __func__);

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
		nfc_err(dev, "No I2C_FUNC_I2C support\n");
		return -ENODEV;
	}

	/* Checking if we have an irq */
	if (client->irq <= 0) {
		nfc_err(dev, "IRQ not present\n");
		return -ENODEV;
	}

	phy = devm_kzalloc(dev, sizeof(struct fdp_i2c_phy),
			   GFP_KERNEL);
	if (!phy)
		return -ENOMEM;

	phy->i2c_dev = client;
	phy->next_read_size = FDP_NCI_I2C_MIN_PAYLOAD;
	i2c_set_clientdata(client, phy);

	r = request_threaded_irq(client->irq, NULL, fdp_nci_i2c_irq_thread_fn,
				 IRQF_TRIGGER_RISING | IRQF_ONESHOT,
				 FDP_I2C_DRIVER_NAME, phy);

	if (r < 0) {
		nfc_err(&client->dev, "Unable to register IRQ handler\n");
		return r;
	}

	/* Requesting the power gpio */
	phy->power_gpio = devm_gpiod_get(dev, FDP_DP_POWER_GPIO_NAME,
					 GPIOD_OUT_LOW);

	if (IS_ERR(phy->power_gpio)) {
		nfc_err(dev, "Power GPIO request failed\n");
		return PTR_ERR(phy->power_gpio);
	}

	/* read device properties to get the clock and production settings */
	fdp_nci_i2c_read_device_properties(dev, &clock_type, &clock_freq,
					   &fw_vsc_cfg);

	/* Call the NFC specific probe function */
	r = fdp_nci_probe(phy, &i2c_phy_ops, &phy->ndev,
			  FDP_FRAME_HEADROOM, FDP_FRAME_TAILROOM,
			  clock_type, clock_freq, fw_vsc_cfg);
	if (r < 0) {
		nfc_err(dev, "NCI probing error\n");
		return r;
	}

	dev_dbg(dev, "I2C driver loaded\n");
	return 0;
}

static int fdp_nci_i2c_remove(struct i2c_client *client)
{
	struct fdp_i2c_phy *phy = i2c_get_clientdata(client);

	dev_dbg(&client->dev, "%s\n", __func__);

	fdp_nci_remove(phy->ndev);
	fdp_nci_i2c_disable(phy);

	return 0;
}

static const struct acpi_device_id fdp_nci_i2c_acpi_match[] = {
	{"INT339A", 0},
	{}
};
MODULE_DEVICE_TABLE(acpi, fdp_nci_i2c_acpi_match);

static struct i2c_driver fdp_nci_i2c_driver = {
	.driver = {
		   .name = FDP_I2C_DRIVER_NAME,
		   .acpi_match_table = ACPI_PTR(fdp_nci_i2c_acpi_match),
		  },
	.probe_new = fdp_nci_i2c_probe,
	.remove = fdp_nci_i2c_remove,
};
module_i2c_driver(fdp_nci_i2c_driver);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("I2C driver for Intel Fields Peak NFC controller");
MODULE_AUTHOR("Robert Dolca <robert.dolca@intel.com>");

Privacy Policy