xref: /kernel/linux/linux-6.6/drivers/nfc/st-nci/spi.c (revision 62306a36) 
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * SPI Link Layer for ST NCI based Driver
4 * Copyright (C) 2014-2015 STMicroelectronics SAS. All rights reserved.
5 */
6
7#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8
9#include <linux/module.h>
10#include <linux/spi/spi.h>
11#include <linux/gpio/consumer.h>
12#include <linux/acpi.h>
13#include <linux/interrupt.h>
14#include <linux/delay.h>
15#include <linux/nfc.h>
16#include <linux/of.h>
17#include <net/nfc/nci.h>
18
19#include "st-nci.h"
20
21#define DRIVER_DESC "NCI NFC driver for ST_NCI"
22
23/* ndlc header */
24#define ST_NCI_FRAME_HEADROOM	1
25#define ST_NCI_FRAME_TAILROOM	0
26
27#define ST_NCI_SPI_MIN_SIZE 4   /* PCB(1) + NCI Packet header(3) */
28#define ST_NCI_SPI_MAX_SIZE 250 /* req 4.2.1 */
29
30#define ST_NCI_DRIVER_NAME "st_nci"
31#define ST_NCI_SPI_DRIVER_NAME "st_nci_spi"
32
33struct st_nci_spi_phy {
34	struct spi_device *spi_dev;
35	struct llt_ndlc *ndlc;
36
37	bool irq_active;
38
39	struct gpio_desc *gpiod_reset;
40
41	struct st_nci_se_status se_status;
42};
43
44static int st_nci_spi_enable(void *phy_id)
45{
46	struct st_nci_spi_phy *phy = phy_id;
47
48	gpiod_set_value(phy->gpiod_reset, 0);
49	usleep_range(10000, 15000);
50	gpiod_set_value(phy->gpiod_reset, 1);
51	usleep_range(80000, 85000);
52
53	if (phy->ndlc->powered == 0 && phy->irq_active == 0) {
54		enable_irq(phy->spi_dev->irq);
55		phy->irq_active = true;
56	}
57
58	return 0;
59}
60
61static void st_nci_spi_disable(void *phy_id)
62{
63	struct st_nci_spi_phy *phy = phy_id;
64
65	disable_irq_nosync(phy->spi_dev->irq);
66	phy->irq_active = false;
67}
68
69/*
70 * Writing a frame must not return the number of written bytes.
71 * It must return either zero for success, or <0 for error.
72 * In addition, it must not alter the skb
73 */
74static int st_nci_spi_write(void *phy_id, struct sk_buff *skb)
75{
76	int r;
77	struct st_nci_spi_phy *phy = phy_id;
78	struct spi_device *dev = phy->spi_dev;
79	struct sk_buff *skb_rx;
80	u8 buf[ST_NCI_SPI_MAX_SIZE + NCI_DATA_HDR_SIZE +
81	       ST_NCI_FRAME_HEADROOM + ST_NCI_FRAME_TAILROOM];
82	struct spi_transfer spi_xfer = {
83		.tx_buf = skb->data,
84		.rx_buf = buf,
85		.len = skb->len,
86	};
87
88	if (phy->ndlc->hard_fault != 0)
89		return phy->ndlc->hard_fault;
90
91	r = spi_sync_transfer(dev, &spi_xfer, 1);
92	/*
93	 * We may have received some valuable data on miso line.
94	 * Send them back in the ndlc state machine.
95	 */
96	if (!r) {
97		skb_rx = alloc_skb(skb->len, GFP_KERNEL);
98		if (!skb_rx)
99			return -ENOMEM;
100
101		skb_put(skb_rx, skb->len);
102		memcpy(skb_rx->data, buf, skb->len);
103		ndlc_recv(phy->ndlc, skb_rx);
104	}
105
106	return r;
107}
108
109/*
110 * Reads an ndlc frame and returns it in a newly allocated sk_buff.
111 * returns:
112 * 0 : if received frame is complete
113 * -EREMOTEIO : i2c read error (fatal)
114 * -EBADMSG : frame was incorrect and discarded
115 * -ENOMEM : cannot allocate skb, frame dropped
116 */
117static int st_nci_spi_read(struct st_nci_spi_phy *phy,
118			struct sk_buff **skb)
119{
120	int r;
121	u8 len;
122	u8 buf[ST_NCI_SPI_MAX_SIZE];
123	struct spi_device *dev = phy->spi_dev;
124	struct spi_transfer spi_xfer = {
125		.rx_buf = buf,
126		.len = ST_NCI_SPI_MIN_SIZE,
127	};
128
129	r = spi_sync_transfer(dev, &spi_xfer, 1);
130	if (r < 0)
131		return -EREMOTEIO;
132
133	len = be16_to_cpu(*(__be16 *) (buf + 2));
134	if (len > ST_NCI_SPI_MAX_SIZE) {
135		nfc_err(&dev->dev, "invalid frame len\n");
136		phy->ndlc->hard_fault = 1;
137		return -EBADMSG;
138	}
139
140	*skb = alloc_skb(ST_NCI_SPI_MIN_SIZE + len, GFP_KERNEL);
141	if (*skb == NULL)
142		return -ENOMEM;
143
144	skb_reserve(*skb, ST_NCI_SPI_MIN_SIZE);
145	skb_put(*skb, ST_NCI_SPI_MIN_SIZE);
146	memcpy((*skb)->data, buf, ST_NCI_SPI_MIN_SIZE);
147
148	if (!len)
149		return 0;
150
151	spi_xfer.len = len;
152	r = spi_sync_transfer(dev, &spi_xfer, 1);
153	if (r < 0) {
154		kfree_skb(*skb);
155		return -EREMOTEIO;
156	}
157
158	skb_put(*skb, len);
159	memcpy((*skb)->data + ST_NCI_SPI_MIN_SIZE, buf, len);
160
161	return 0;
162}
163
164/*
165 * Reads an ndlc frame from the chip.
166 *
167 * On ST21NFCB, IRQ goes in idle state when read starts.
168 */
169static irqreturn_t st_nci_irq_thread_fn(int irq, void *phy_id)
170{
171	struct st_nci_spi_phy *phy = phy_id;
172	struct sk_buff *skb = NULL;
173	int r;
174
175	if (!phy || !phy->ndlc || irq != phy->spi_dev->irq) {
176		WARN_ON_ONCE(1);
177		return IRQ_NONE;
178	}
179
180	if (phy->ndlc->hard_fault)
181		return IRQ_HANDLED;
182
183	if (!phy->ndlc->powered) {
184		st_nci_spi_disable(phy);
185		return IRQ_HANDLED;
186	}
187
188	r = st_nci_spi_read(phy, &skb);
189	if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG)
190		return IRQ_HANDLED;
191
192	ndlc_recv(phy->ndlc, skb);
193
194	return IRQ_HANDLED;
195}
196
197static const struct nfc_phy_ops spi_phy_ops = {
198	.write = st_nci_spi_write,
199	.enable = st_nci_spi_enable,
200	.disable = st_nci_spi_disable,
201};
202
203static const struct acpi_gpio_params reset_gpios = { 1, 0, false };
204
205static const struct acpi_gpio_mapping acpi_st_nci_gpios[] = {
206	{ "reset-gpios", &reset_gpios, 1 },
207	{},
208};
209
210static int st_nci_spi_probe(struct spi_device *dev)
211{
212	struct st_nci_spi_phy *phy;
213	int r;
214
215	/* Check SPI platform functionnalities */
216	if (!dev) {
217		pr_debug("%s: dev is NULL. Device is not accessible.\n",
218			__func__);
219		return -ENODEV;
220	}
221
222	phy = devm_kzalloc(&dev->dev, sizeof(struct st_nci_spi_phy),
223			   GFP_KERNEL);
224	if (!phy)
225		return -ENOMEM;
226
227	phy->spi_dev = dev;
228
229	spi_set_drvdata(dev, phy);
230
231	r = devm_acpi_dev_add_driver_gpios(&dev->dev, acpi_st_nci_gpios);
232	if (r)
233		dev_dbg(&dev->dev, "Unable to add GPIO mapping table\n");
234
235	/* Get RESET GPIO */
236	phy->gpiod_reset = devm_gpiod_get(&dev->dev, "reset", GPIOD_OUT_HIGH);
237	if (IS_ERR(phy->gpiod_reset)) {
238		nfc_err(&dev->dev, "Unable to get RESET GPIO\n");
239		return PTR_ERR(phy->gpiod_reset);
240	}
241
242	phy->se_status.is_ese_present =
243			device_property_read_bool(&dev->dev, "ese-present");
244	phy->se_status.is_uicc_present =
245			device_property_read_bool(&dev->dev, "uicc-present");
246
247	r = ndlc_probe(phy, &spi_phy_ops, &dev->dev,
248			ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM,
249			&phy->ndlc, &phy->se_status);
250	if (r < 0) {
251		nfc_err(&dev->dev, "Unable to register ndlc layer\n");
252		return r;
253	}
254
255	phy->irq_active = true;
256	r = devm_request_threaded_irq(&dev->dev, dev->irq, NULL,
257				st_nci_irq_thread_fn,
258				IRQF_ONESHOT,
259				ST_NCI_SPI_DRIVER_NAME, phy);
260	if (r < 0)
261		nfc_err(&dev->dev, "Unable to register IRQ handler\n");
262
263	return r;
264}
265
266static void st_nci_spi_remove(struct spi_device *dev)
267{
268	struct st_nci_spi_phy *phy = spi_get_drvdata(dev);
269
270	ndlc_remove(phy->ndlc);
271}
272
273static struct spi_device_id st_nci_spi_id_table[] = {
274	{ST_NCI_SPI_DRIVER_NAME, 0},
275	{"st21nfcb-spi", 0},
276	{}
277};
278MODULE_DEVICE_TABLE(spi, st_nci_spi_id_table);
279
280static const struct acpi_device_id st_nci_spi_acpi_match[] __maybe_unused = {
281	{"SMO2101", 0},
282	{}
283};
284MODULE_DEVICE_TABLE(acpi, st_nci_spi_acpi_match);
285
286static const struct of_device_id of_st_nci_spi_match[] __maybe_unused = {
287	{ .compatible = "st,st21nfcb-spi", },
288	{}
289};
290MODULE_DEVICE_TABLE(of, of_st_nci_spi_match);
291
292static struct spi_driver st_nci_spi_driver = {
293	.driver = {
294		.name = ST_NCI_SPI_DRIVER_NAME,
295		.of_match_table = of_match_ptr(of_st_nci_spi_match),
296		.acpi_match_table = ACPI_PTR(st_nci_spi_acpi_match),
297	},
298	.probe = st_nci_spi_probe,
299	.id_table = st_nci_spi_id_table,
300	.remove = st_nci_spi_remove,
301};
302module_spi_driver(st_nci_spi_driver);
303
304MODULE_LICENSE("GPL");
305MODULE_DESCRIPTION(DRIVER_DESC);
306