summaryrefslogtreecommitdiff
path: root/drivers/nfc/st-nci/spi.c
blob: 169eacc0a32aeb18ddf6d2c2148be59777c95ee1 (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
// SPDX-License-Identifier: GPL-2.0-only
/*
 * SPI Link Layer for ST NCI based Driver
 * Copyright (C) 2014-2015 STMicroelectronics SAS. All rights reserved.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/spi/spi.h>
#include <linux/gpio/consumer.h>
#include <linux/acpi.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/nfc.h>
#include <linux/of.h>
#include <net/nfc/nci.h>

#include "st-nci.h"

#define DRIVER_DESC "NCI NFC driver for ST_NCI"

/* ndlc header */
#define ST_NCI_FRAME_HEADROOM	1
#define ST_NCI_FRAME_TAILROOM	0

#define ST_NCI_SPI_MIN_SIZE 4   /* PCB(1) + NCI Packet header(3) */
#define ST_NCI_SPI_MAX_SIZE 250 /* req 4.2.1 */

#define ST_NCI_DRIVER_NAME "st_nci"
#define ST_NCI_SPI_DRIVER_NAME "st_nci_spi"

struct st_nci_spi_phy {
	struct spi_device *spi_dev;
	struct llt_ndlc *ndlc;

	bool irq_active;

	struct gpio_desc *gpiod_reset;

	struct st_nci_se_status se_status;
};

static int st_nci_spi_enable(void *phy_id)
{
	struct st_nci_spi_phy *phy = phy_id;

	gpiod_set_value(phy->gpiod_reset, 0);
	usleep_range(10000, 15000);
	gpiod_set_value(phy->gpiod_reset, 1);
	usleep_range(80000, 85000);

	if (phy->ndlc->powered == 0 && phy->irq_active == 0) {
		enable_irq(phy->spi_dev->irq);
		phy->irq_active = true;
	}

	return 0;
}

static void st_nci_spi_disable(void *phy_id)
{
	struct st_nci_spi_phy *phy = phy_id;

	disable_irq_nosync(phy->spi_dev->irq);
	phy->irq_active = false;
}

/*
 * Writing a frame must not return the number of written bytes.
 * It must return either zero for success, or <0 for error.
 * In addition, it must not alter the skb
 */
static int st_nci_spi_write(void *phy_id, struct sk_buff *skb)
{
	int r;
	struct st_nci_spi_phy *phy = phy_id;
	struct spi_device *dev = phy->spi_dev;
	struct sk_buff *skb_rx;
	u8 buf[ST_NCI_SPI_MAX_SIZE + NCI_DATA_HDR_SIZE +
	       ST_NCI_FRAME_HEADROOM + ST_NCI_FRAME_TAILROOM];
	struct spi_transfer spi_xfer = {
		.tx_buf = skb->data,
		.rx_buf = buf,
		.len = skb->len,
	};

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

	r = spi_sync_transfer(dev, &spi_xfer, 1);
	/*
	 * We may have received some valuable data on miso line.
	 * Send them back in the ndlc state machine.
	 */
	if (!r) {
		skb_rx = alloc_skb(skb->len, GFP_KERNEL);
		if (!skb_rx)
			return -ENOMEM;

		skb_put(skb_rx, skb->len);
		memcpy(skb_rx->data, buf, skb->len);
		ndlc_recv(phy->ndlc, skb_rx);
	}

	return r;
}

/*
 * Reads an ndlc frame and returns it in a newly allocated sk_buff.
 * returns:
 * 0 : if received frame is complete
 * -EREMOTEIO : i2c read error (fatal)
 * -EBADMSG : frame was incorrect and discarded
 * -ENOMEM : cannot allocate skb, frame dropped
 */
static int st_nci_spi_read(struct st_nci_spi_phy *phy,
			struct sk_buff **skb)
{
	int r;
	u8 len;
	u8 buf[ST_NCI_SPI_MAX_SIZE];
	struct spi_device *dev = phy->spi_dev;
	struct spi_transfer spi_xfer = {
		.rx_buf = buf,
		.len = ST_NCI_SPI_MIN_SIZE,
	};

	r = spi_sync_transfer(dev, &spi_xfer, 1);
	if (r < 0)
		return -EREMOTEIO;

	len = be16_to_cpu(*(__be16 *) (buf + 2));
	if (len > ST_NCI_SPI_MAX_SIZE) {
		nfc_err(&dev->dev, "invalid frame len\n");
		phy->ndlc->hard_fault = 1;
		return -EBADMSG;
	}

	*skb = alloc_skb(ST_NCI_SPI_MIN_SIZE + len, GFP_KERNEL);
	if (*skb == NULL)
		return -ENOMEM;

	skb_reserve(*skb, ST_NCI_SPI_MIN_SIZE);
	skb_put(*skb, ST_NCI_SPI_MIN_SIZE);
	memcpy((*skb)->data, buf, ST_NCI_SPI_MIN_SIZE);

	if (!len)
		return 0;

	spi_xfer.len = len;
	r = spi_sync_transfer(dev, &spi_xfer, 1);
	if (r < 0) {
		kfree_skb(*skb);
		return -EREMOTEIO;
	}

	skb_put(*skb, len);
	memcpy((*skb)->data + ST_NCI_SPI_MIN_SIZE, buf, len);

	return 0;
}

/*
 * Reads an ndlc frame from the chip.
 *
 * On ST21NFCB, IRQ goes in idle state when read starts.
 */
static irqreturn_t st_nci_irq_thread_fn(int irq, void *phy_id)
{
	struct st_nci_spi_phy *phy = phy_id;
	struct sk_buff *skb = NULL;
	int r;

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

	if (phy->ndlc->hard_fault)
		return IRQ_HANDLED;

	if (!phy->ndlc->powered) {
		st_nci_spi_disable(phy);
		return IRQ_HANDLED;
	}

	r = st_nci_spi_read(phy, &skb);
	if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG)
		return IRQ_HANDLED;

	ndlc_recv(phy->ndlc, skb);

	return IRQ_HANDLED;
}

static const struct nfc_phy_ops spi_phy_ops = {
	.write = st_nci_spi_write,
	.enable = st_nci_spi_enable,
	.disable = st_nci_spi_disable,
};

static const struct acpi_gpio_params reset_gpios = { 1, 0, false };

static const struct acpi_gpio_mapping acpi_st_nci_gpios[] = {
	{ "reset-gpios", &reset_gpios, 1 },
	{},
};

static int st_nci_spi_probe(struct spi_device *dev)
{
	struct st_nci_spi_phy *phy;
	int r;

	/* Check SPI platform functionnalities */
	if (!dev) {
		pr_debug("%s: dev is NULL. Device is not accessible.\n",
			__func__);
		return -ENODEV;
	}

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

	phy->spi_dev = dev;

	spi_set_drvdata(dev, phy);

	r = devm_acpi_dev_add_driver_gpios(&dev->dev, acpi_st_nci_gpios);
	if (r)
		dev_dbg(&dev->dev, "Unable to add GPIO mapping table\n");

	/* Get RESET GPIO */
	phy->gpiod_reset = devm_gpiod_get(&dev->dev, "reset", GPIOD_OUT_HIGH);
	if (IS_ERR(phy->gpiod_reset)) {
		nfc_err(&dev->dev, "Unable to get RESET GPIO\n");
		return PTR_ERR(phy->gpiod_reset);
	}

	phy->se_status.is_ese_present =
			device_property_read_bool(&dev->dev, "ese-present");
	phy->se_status.is_uicc_present =
			device_property_read_bool(&dev->dev, "uicc-present");

	r = ndlc_probe(phy, &spi_phy_ops, &dev->dev,
			ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM,
			&phy->ndlc, &phy->se_status);
	if (r < 0) {
		nfc_err(&dev->dev, "Unable to register ndlc layer\n");
		return r;
	}

	phy->irq_active = true;
	r = devm_request_threaded_irq(&dev->dev, dev->irq, NULL,
				st_nci_irq_thread_fn,
				IRQF_ONESHOT,
				ST_NCI_SPI_DRIVER_NAME, phy);
	if (r < 0)
		nfc_err(&dev->dev, "Unable to register IRQ handler\n");

	return r;
}

static void st_nci_spi_remove(struct spi_device *dev)
{
	struct st_nci_spi_phy *phy = spi_get_drvdata(dev);

	ndlc_remove(phy->ndlc);
}

static struct spi_device_id st_nci_spi_id_table[] = {
	{ST_NCI_SPI_DRIVER_NAME, 0},
	{"st21nfcb-spi", 0},
	{}
};
MODULE_DEVICE_TABLE(spi, st_nci_spi_id_table);

static const struct acpi_device_id st_nci_spi_acpi_match[] __maybe_unused = {
	{"SMO2101", 0},
	{}
};
MODULE_DEVICE_TABLE(acpi, st_nci_spi_acpi_match);

static const struct of_device_id of_st_nci_spi_match[] __maybe_unused = {
	{ .compatible = "st,st21nfcb-spi", },
	{}
};
MODULE_DEVICE_TABLE(of, of_st_nci_spi_match);

static struct spi_driver st_nci_spi_driver = {
	.driver = {
		.name = ST_NCI_SPI_DRIVER_NAME,
		.of_match_table = of_match_ptr(of_st_nci_spi_match),
		.acpi_match_table = ACPI_PTR(st_nci_spi_acpi_match),
	},
	.probe = st_nci_spi_probe,
	.id_table = st_nci_spi_id_table,
	.remove = st_nci_spi_remove,
};
module_spi_driver(st_nci_spi_driver);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION(DRIVER_DESC);