xref: /openbmc/linux/drivers/nfc/pn533/i2c.c (revision 4a3fad70)
1 /*
2  * Driver for NXP PN533 NFC Chip - I2C transport layer
3  *
4  * Copyright (C) 2011 Instituto Nokia de Tecnologia
5  * Copyright (C) 2012-2013 Tieto Poland
6  * Copyright (C) 2016 HALE electronic
7  *
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License as published by
11  * the Free Software Foundation; either version 2 of the License, or
12  * (at your option) any later version.
13  *
14  * This program is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17  * GNU General Public License for more details.
18  *
19  * You should have received a copy of the GNU General Public License
20  * along with this program; if not, see <http://www.gnu.org/licenses/>.
21  */
22 
23 #include <linux/device.h>
24 #include <linux/kernel.h>
25 #include <linux/module.h>
26 #include <linux/slab.h>
27 #include <linux/i2c.h>
28 #include <linux/nfc.h>
29 #include <linux/netdevice.h>
30 #include <linux/interrupt.h>
31 #include <net/nfc/nfc.h>
32 #include "pn533.h"
33 
34 #define VERSION "0.1"
35 
36 #define PN533_I2C_DRIVER_NAME "pn533_i2c"
37 
38 struct pn533_i2c_phy {
39 	struct i2c_client *i2c_dev;
40 	struct pn533 *priv;
41 
42 	bool aborted;
43 
44 	int hard_fault;		/*
45 				 * < 0 if hardware error occurred (e.g. i2c err)
46 				 * and prevents normal operation.
47 				 */
48 };
49 
50 static int pn533_i2c_send_ack(struct pn533 *dev, gfp_t flags)
51 {
52 	struct pn533_i2c_phy *phy = dev->phy;
53 	struct i2c_client *client = phy->i2c_dev;
54 	static const u8 ack[6] = {0x00, 0x00, 0xff, 0x00, 0xff, 0x00};
55 	/* spec 6.2.1.3:  Preamble, SoPC (2), ACK Code (2), Postamble */
56 	int rc;
57 
58 	rc = i2c_master_send(client, ack, 6);
59 
60 	return rc;
61 }
62 
63 static int pn533_i2c_send_frame(struct pn533 *dev,
64 				struct sk_buff *out)
65 {
66 	struct pn533_i2c_phy *phy = dev->phy;
67 	struct i2c_client *client = phy->i2c_dev;
68 	int rc;
69 
70 	if (phy->hard_fault != 0)
71 		return phy->hard_fault;
72 
73 	if (phy->priv == NULL)
74 		phy->priv = dev;
75 
76 	phy->aborted = false;
77 
78 	print_hex_dump_debug("PN533_i2c TX: ", DUMP_PREFIX_NONE, 16, 1,
79 			     out->data, out->len, false);
80 
81 	rc = i2c_master_send(client, out->data, out->len);
82 
83 	if (rc == -EREMOTEIO) { /* Retry, chip was in power down */
84 		usleep_range(6000, 10000);
85 		rc = i2c_master_send(client, out->data, out->len);
86 	}
87 
88 	if (rc >= 0) {
89 		if (rc != out->len)
90 			rc = -EREMOTEIO;
91 		else
92 			rc = 0;
93 	}
94 
95 	return rc;
96 }
97 
98 static void pn533_i2c_abort_cmd(struct pn533 *dev, gfp_t flags)
99 {
100 	struct pn533_i2c_phy *phy = dev->phy;
101 
102 	phy->aborted = true;
103 
104 	/* An ack will cancel the last issued command */
105 	pn533_i2c_send_ack(dev, flags);
106 
107 	/* schedule cmd_complete_work to finish current command execution */
108 	pn533_recv_frame(phy->priv, NULL, -ENOENT);
109 }
110 
111 static int pn533_i2c_read(struct pn533_i2c_phy *phy, struct sk_buff **skb)
112 {
113 	struct i2c_client *client = phy->i2c_dev;
114 	int len = PN533_EXT_FRAME_HEADER_LEN +
115 		  PN533_STD_FRAME_MAX_PAYLOAD_LEN +
116 		  PN533_STD_FRAME_TAIL_LEN + 1;
117 	int r;
118 
119 	*skb = alloc_skb(len, GFP_KERNEL);
120 	if (*skb == NULL)
121 		return -ENOMEM;
122 
123 	r = i2c_master_recv(client, skb_put(*skb, len), len);
124 	if (r != len) {
125 		nfc_err(&client->dev, "cannot read. r=%d len=%d\n", r, len);
126 		kfree_skb(*skb);
127 		return -EREMOTEIO;
128 	}
129 
130 	if (!((*skb)->data[0] & 0x01)) {
131 		nfc_err(&client->dev, "READY flag not set");
132 		kfree_skb(*skb);
133 		return -EBUSY;
134 	}
135 
136 	/* remove READY byte */
137 	skb_pull(*skb, 1);
138 	/* trim to frame size */
139 	skb_trim(*skb, phy->priv->ops->rx_frame_size((*skb)->data));
140 
141 	return 0;
142 }
143 
144 static irqreturn_t pn533_i2c_irq_thread_fn(int irq, void *data)
145 {
146 	struct pn533_i2c_phy *phy = data;
147 	struct i2c_client *client;
148 	struct sk_buff *skb = NULL;
149 	int r;
150 
151 	if (!phy || irq != phy->i2c_dev->irq) {
152 		WARN_ON_ONCE(1);
153 		return IRQ_NONE;
154 	}
155 
156 	client = phy->i2c_dev;
157 	dev_dbg(&client->dev, "IRQ\n");
158 
159 	if (phy->hard_fault != 0)
160 		return IRQ_HANDLED;
161 
162 	r = pn533_i2c_read(phy, &skb);
163 	if (r == -EREMOTEIO) {
164 		phy->hard_fault = r;
165 
166 		pn533_recv_frame(phy->priv, NULL, -EREMOTEIO);
167 
168 		return IRQ_HANDLED;
169 	} else if ((r == -ENOMEM) || (r == -EBADMSG) || (r == -EBUSY)) {
170 		return IRQ_HANDLED;
171 	}
172 
173 	if (!phy->aborted)
174 		pn533_recv_frame(phy->priv, skb, 0);
175 
176 	return IRQ_HANDLED;
177 }
178 
179 static struct pn533_phy_ops i2c_phy_ops = {
180 	.send_frame = pn533_i2c_send_frame,
181 	.send_ack = pn533_i2c_send_ack,
182 	.abort_cmd = pn533_i2c_abort_cmd,
183 };
184 
185 
186 static int pn533_i2c_probe(struct i2c_client *client,
187 			       const struct i2c_device_id *id)
188 {
189 	struct pn533_i2c_phy *phy;
190 	struct pn533 *priv;
191 	int r = 0;
192 
193 	dev_dbg(&client->dev, "%s\n", __func__);
194 	dev_dbg(&client->dev, "IRQ: %d\n", client->irq);
195 
196 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
197 		nfc_err(&client->dev, "Need I2C_FUNC_I2C\n");
198 		return -ENODEV;
199 	}
200 
201 	phy = devm_kzalloc(&client->dev, sizeof(struct pn533_i2c_phy),
202 			   GFP_KERNEL);
203 	if (!phy)
204 		return -ENOMEM;
205 
206 	phy->i2c_dev = client;
207 	i2c_set_clientdata(client, phy);
208 
209 	priv = pn533_register_device(PN533_DEVICE_PN532,
210 				     PN533_NO_TYPE_B_PROTOCOLS,
211 				     PN533_PROTO_REQ_ACK_RESP,
212 				     phy, &i2c_phy_ops, NULL,
213 				     &phy->i2c_dev->dev,
214 				     &client->dev);
215 
216 	if (IS_ERR(priv)) {
217 		r = PTR_ERR(priv);
218 		return r;
219 	}
220 
221 	phy->priv = priv;
222 
223 	r = request_threaded_irq(client->irq, NULL, pn533_i2c_irq_thread_fn,
224 				IRQF_TRIGGER_FALLING |
225 				IRQF_SHARED | IRQF_ONESHOT,
226 				PN533_I2C_DRIVER_NAME, phy);
227 	if (r < 0) {
228 		nfc_err(&client->dev, "Unable to register IRQ handler\n");
229 		goto irq_rqst_err;
230 	}
231 
232 	r = pn533_finalize_setup(priv);
233 	if (r)
234 		goto fn_setup_err;
235 
236 	return 0;
237 
238 fn_setup_err:
239 	free_irq(client->irq, phy);
240 
241 irq_rqst_err:
242 	pn533_unregister_device(phy->priv);
243 
244 	return r;
245 }
246 
247 static int pn533_i2c_remove(struct i2c_client *client)
248 {
249 	struct pn533_i2c_phy *phy = i2c_get_clientdata(client);
250 
251 	dev_dbg(&client->dev, "%s\n", __func__);
252 
253 	free_irq(client->irq, phy);
254 
255 	pn533_unregister_device(phy->priv);
256 
257 	return 0;
258 }
259 
260 static const struct of_device_id of_pn533_i2c_match[] = {
261 	{ .compatible = "nxp,pn533-i2c", },
262 	{ .compatible = "nxp,pn532-i2c", },
263 	{},
264 };
265 MODULE_DEVICE_TABLE(of, of_pn533_i2c_match);
266 
267 static const struct i2c_device_id pn533_i2c_id_table[] = {
268 	{ PN533_I2C_DRIVER_NAME, 0 },
269 	{}
270 };
271 MODULE_DEVICE_TABLE(i2c, pn533_i2c_id_table);
272 
273 static struct i2c_driver pn533_i2c_driver = {
274 	.driver = {
275 		   .name = PN533_I2C_DRIVER_NAME,
276 		   .owner = THIS_MODULE,
277 		   .of_match_table = of_match_ptr(of_pn533_i2c_match),
278 		  },
279 	.probe = pn533_i2c_probe,
280 	.id_table = pn533_i2c_id_table,
281 	.remove = pn533_i2c_remove,
282 };
283 
284 module_i2c_driver(pn533_i2c_driver);
285 
286 MODULE_AUTHOR("Michael Thalmeier <michael.thalmeier@hale.at>");
287 MODULE_DESCRIPTION("PN533 I2C driver ver " VERSION);
288 MODULE_VERSION(VERSION);
289 MODULE_LICENSE("GPL");
290