1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * I2C Link Layer for ST NCI NFC controller familly 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/i2c.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
18#include "st-nci.h"
19
20#define DRIVER_DESC "NCI NFC driver for ST_NCI"
21
22/* ndlc header */
23#define ST_NCI_FRAME_HEADROOM 1
24#define ST_NCI_FRAME_TAILROOM 0
25
26#define ST_NCI_I2C_MIN_SIZE 4   /* PCB(1) + NCI Packet header(3) */
27#define ST_NCI_I2C_MAX_SIZE 250 /* req 4.2.1 */
28
29#define ST_NCI_DRIVER_NAME "st_nci"
30#define ST_NCI_I2C_DRIVER_NAME "st_nci_i2c"
31
32struct st_nci_i2c_phy {
33	struct i2c_client *i2c_dev;
34	struct llt_ndlc *ndlc;
35
36	bool irq_active;
37
38	struct gpio_desc *gpiod_reset;
39
40	struct st_nci_se_status se_status;
41};
42
43static int st_nci_i2c_enable(void *phy_id)
44{
45	struct st_nci_i2c_phy *phy = phy_id;
46
47	gpiod_set_value(phy->gpiod_reset, 0);
48	usleep_range(10000, 15000);
49	gpiod_set_value(phy->gpiod_reset, 1);
50	usleep_range(80000, 85000);
51
52	if (phy->ndlc->powered == 0 && phy->irq_active == 0) {
53		enable_irq(phy->i2c_dev->irq);
54		phy->irq_active = true;
55	}
56
57	return 0;
58}
59
60static void st_nci_i2c_disable(void *phy_id)
61{
62	struct st_nci_i2c_phy *phy = phy_id;
63
64	disable_irq_nosync(phy->i2c_dev->irq);
65	phy->irq_active = false;
66}
67
68/*
69 * Writing a frame must not return the number of written bytes.
70 * It must return either zero for success, or <0 for error.
71 * In addition, it must not alter the skb
72 */
73static int st_nci_i2c_write(void *phy_id, struct sk_buff *skb)
74{
75	int r;
76	struct st_nci_i2c_phy *phy = phy_id;
77	struct i2c_client *client = phy->i2c_dev;
78
79	if (phy->ndlc->hard_fault != 0)
80		return phy->ndlc->hard_fault;
81
82	r = i2c_master_send(client, skb->data, skb->len);
83	if (r < 0) {  /* Retry, chip was in standby */
84		usleep_range(1000, 4000);
85		r = i2c_master_send(client, skb->data, skb->len);
86	}
87
88	if (r >= 0) {
89		if (r != skb->len)
90			r = -EREMOTEIO;
91		else
92			r = 0;
93	}
94
95	return r;
96}
97
98/*
99 * Reads an ndlc frame and returns it in a newly allocated sk_buff.
100 * returns:
101 * 0 : if received frame is complete
102 * -EREMOTEIO : i2c read error (fatal)
103 * -EBADMSG : frame was incorrect and discarded
104 * -ENOMEM : cannot allocate skb, frame dropped
105 */
106static int st_nci_i2c_read(struct st_nci_i2c_phy *phy,
107				 struct sk_buff **skb)
108{
109	int r;
110	u8 len;
111	u8 buf[ST_NCI_I2C_MAX_SIZE];
112	struct i2c_client *client = phy->i2c_dev;
113
114	r = i2c_master_recv(client, buf, ST_NCI_I2C_MIN_SIZE);
115	if (r < 0) {  /* Retry, chip was in standby */
116		usleep_range(1000, 4000);
117		r = i2c_master_recv(client, buf, ST_NCI_I2C_MIN_SIZE);
118	}
119
120	if (r != ST_NCI_I2C_MIN_SIZE)
121		return -EREMOTEIO;
122
123	len = be16_to_cpu(*(__be16 *) (buf + 2));
124	if (len > ST_NCI_I2C_MAX_SIZE) {
125		nfc_err(&client->dev, "invalid frame len\n");
126		return -EBADMSG;
127	}
128
129	*skb = alloc_skb(ST_NCI_I2C_MIN_SIZE + len, GFP_KERNEL);
130	if (*skb == NULL)
131		return -ENOMEM;
132
133	skb_reserve(*skb, ST_NCI_I2C_MIN_SIZE);
134	skb_put(*skb, ST_NCI_I2C_MIN_SIZE);
135	memcpy((*skb)->data, buf, ST_NCI_I2C_MIN_SIZE);
136
137	if (!len)
138		return 0;
139
140	r = i2c_master_recv(client, buf, len);
141	if (r != len) {
142		kfree_skb(*skb);
143		return -EREMOTEIO;
144	}
145
146	skb_put(*skb, len);
147	memcpy((*skb)->data + ST_NCI_I2C_MIN_SIZE, buf, len);
148
149	return 0;
150}
151
152/*
153 * Reads an ndlc frame from the chip.
154 *
155 * On ST_NCI, IRQ goes in idle state when read starts.
156 */
157static irqreturn_t st_nci_irq_thread_fn(int irq, void *phy_id)
158{
159	struct st_nci_i2c_phy *phy = phy_id;
160	struct sk_buff *skb = NULL;
161	int r;
162
163	if (!phy || !phy->ndlc || irq != phy->i2c_dev->irq) {
164		WARN_ON_ONCE(1);
165		return IRQ_NONE;
166	}
167
168	if (phy->ndlc->hard_fault)
169		return IRQ_HANDLED;
170
171	if (!phy->ndlc->powered) {
172		st_nci_i2c_disable(phy);
173		return IRQ_HANDLED;
174	}
175
176	r = st_nci_i2c_read(phy, &skb);
177	if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG)
178		return IRQ_HANDLED;
179
180	ndlc_recv(phy->ndlc, skb);
181
182	return IRQ_HANDLED;
183}
184
185static const struct nfc_phy_ops i2c_phy_ops = {
186	.write = st_nci_i2c_write,
187	.enable = st_nci_i2c_enable,
188	.disable = st_nci_i2c_disable,
189};
190
191static const struct acpi_gpio_params reset_gpios = { 1, 0, false };
192
193static const struct acpi_gpio_mapping acpi_st_nci_gpios[] = {
194	{ "reset-gpios", &reset_gpios, 1 },
195	{},
196};
197
198static int st_nci_i2c_probe(struct i2c_client *client)
199{
200	struct device *dev = &client->dev;
201	struct st_nci_i2c_phy *phy;
202	int r;
203
204	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
205		nfc_err(&client->dev, "Need I2C_FUNC_I2C\n");
206		return -ENODEV;
207	}
208
209	phy = devm_kzalloc(dev, sizeof(struct st_nci_i2c_phy), GFP_KERNEL);
210	if (!phy)
211		return -ENOMEM;
212
213	phy->i2c_dev = client;
214
215	i2c_set_clientdata(client, phy);
216
217	r = devm_acpi_dev_add_driver_gpios(dev, acpi_st_nci_gpios);
218	if (r)
219		dev_dbg(dev, "Unable to add GPIO mapping table\n");
220
221	/* Get RESET GPIO */
222	phy->gpiod_reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
223	if (IS_ERR(phy->gpiod_reset)) {
224		nfc_err(dev, "Unable to get RESET GPIO\n");
225		return -ENODEV;
226	}
227
228	phy->se_status.is_ese_present =
229				device_property_read_bool(dev, "ese-present");
230	phy->se_status.is_uicc_present =
231				device_property_read_bool(dev, "uicc-present");
232
233	r = ndlc_probe(phy, &i2c_phy_ops, &client->dev,
234			ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM,
235			&phy->ndlc, &phy->se_status);
236	if (r < 0) {
237		nfc_err(&client->dev, "Unable to register ndlc layer\n");
238		return r;
239	}
240
241	phy->irq_active = true;
242	r = devm_request_threaded_irq(&client->dev, client->irq, NULL,
243				st_nci_irq_thread_fn,
244				IRQF_ONESHOT,
245				ST_NCI_DRIVER_NAME, phy);
246	if (r < 0)
247		nfc_err(&client->dev, "Unable to register IRQ handler\n");
248
249	return r;
250}
251
252static void st_nci_i2c_remove(struct i2c_client *client)
253{
254	struct st_nci_i2c_phy *phy = i2c_get_clientdata(client);
255
256	ndlc_remove(phy->ndlc);
257}
258
259static const struct i2c_device_id st_nci_i2c_id_table[] = {
260	{ST_NCI_DRIVER_NAME, 0},
261	{}
262};
263MODULE_DEVICE_TABLE(i2c, st_nci_i2c_id_table);
264
265static const struct acpi_device_id st_nci_i2c_acpi_match[] __maybe_unused = {
266	{"SMO2101"},
267	{"SMO2102"},
268	{}
269};
270MODULE_DEVICE_TABLE(acpi, st_nci_i2c_acpi_match);
271
272static const struct of_device_id of_st_nci_i2c_match[] __maybe_unused = {
273	{ .compatible = "st,st21nfcb-i2c", },
274	{ .compatible = "st,st21nfcb_i2c", },
275	{ .compatible = "st,st21nfcc-i2c", },
276	{}
277};
278MODULE_DEVICE_TABLE(of, of_st_nci_i2c_match);
279
280static struct i2c_driver st_nci_i2c_driver = {
281	.driver = {
282		.name = ST_NCI_I2C_DRIVER_NAME,
283		.of_match_table = of_match_ptr(of_st_nci_i2c_match),
284		.acpi_match_table = ACPI_PTR(st_nci_i2c_acpi_match),
285	},
286	.probe = st_nci_i2c_probe,
287	.id_table = st_nci_i2c_id_table,
288	.remove = st_nci_i2c_remove,
289};
290module_i2c_driver(st_nci_i2c_driver);
291
292MODULE_LICENSE("GPL");
293MODULE_DESCRIPTION(DRIVER_DESC);
294