xref: /openbmc/linux/drivers/nfc/st-nci/i2c.c (revision 9b9c2cd4)
1 /*
2  * I2C Link Layer for ST NCI NFC controller familly based Driver
3  * Copyright (C) 2014-2015 STMicroelectronics SAS. All rights reserved.
4  *
5  * This program is free software; you can redistribute it and/or modify it
6  * under the terms and conditions of the GNU General Public License,
7  * version 2, as published by the Free Software Foundation.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, see <http://www.gnu.org/licenses/>.
16  */
17 
18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
19 
20 #include <linux/module.h>
21 #include <linux/i2c.h>
22 #include <linux/gpio.h>
23 #include <linux/of_irq.h>
24 #include <linux/of_gpio.h>
25 #include <linux/interrupt.h>
26 #include <linux/delay.h>
27 #include <linux/nfc.h>
28 #include <linux/platform_data/st-nci.h>
29 
30 #include "st-nci.h"
31 
32 #define DRIVER_DESC "NCI NFC driver for ST_NCI"
33 
34 /* ndlc header */
35 #define ST_NCI_FRAME_HEADROOM 1
36 #define ST_NCI_FRAME_TAILROOM 0
37 
38 #define ST_NCI_I2C_MIN_SIZE 4   /* PCB(1) + NCI Packet header(3) */
39 #define ST_NCI_I2C_MAX_SIZE 250 /* req 4.2.1 */
40 
41 #define ST_NCI_I2C_DRIVER_NAME "st_nci_i2c"
42 
43 static struct i2c_device_id st_nci_i2c_id_table[] = {
44 	{ST_NCI_DRIVER_NAME, 0},
45 	{}
46 };
47 MODULE_DEVICE_TABLE(i2c, st_nci_i2c_id_table);
48 
49 struct st_nci_i2c_phy {
50 	struct i2c_client *i2c_dev;
51 	struct llt_ndlc *ndlc;
52 
53 	bool irq_active;
54 
55 	unsigned int gpio_reset;
56 	unsigned int irq_polarity;
57 
58 	struct st_nci_se_status se_status;
59 };
60 
61 static int st_nci_i2c_enable(void *phy_id)
62 {
63 	struct st_nci_i2c_phy *phy = phy_id;
64 
65 	gpio_set_value(phy->gpio_reset, 0);
66 	usleep_range(10000, 15000);
67 	gpio_set_value(phy->gpio_reset, 1);
68 	usleep_range(80000, 85000);
69 
70 	if (phy->ndlc->powered == 0 && phy->irq_active == 0) {
71 		enable_irq(phy->i2c_dev->irq);
72 		phy->irq_active = true;
73 	}
74 
75 	return 0;
76 }
77 
78 static void st_nci_i2c_disable(void *phy_id)
79 {
80 	struct st_nci_i2c_phy *phy = phy_id;
81 
82 	disable_irq_nosync(phy->i2c_dev->irq);
83 	phy->irq_active = false;
84 }
85 
86 /*
87  * Writing a frame must not return the number of written bytes.
88  * It must return either zero for success, or <0 for error.
89  * In addition, it must not alter the skb
90  */
91 static int st_nci_i2c_write(void *phy_id, struct sk_buff *skb)
92 {
93 	int r = -1;
94 	struct st_nci_i2c_phy *phy = phy_id;
95 	struct i2c_client *client = phy->i2c_dev;
96 
97 	if (phy->ndlc->hard_fault != 0)
98 		return phy->ndlc->hard_fault;
99 
100 	r = i2c_master_send(client, skb->data, skb->len);
101 	if (r < 0) {  /* Retry, chip was in standby */
102 		usleep_range(1000, 4000);
103 		r = i2c_master_send(client, skb->data, skb->len);
104 	}
105 
106 	if (r >= 0) {
107 		if (r != skb->len)
108 			r = -EREMOTEIO;
109 		else
110 			r = 0;
111 	}
112 
113 	return r;
114 }
115 
116 /*
117  * Reads an ndlc frame and returns it in a newly allocated sk_buff.
118  * returns:
119  * 0 : if received frame is complete
120  * -EREMOTEIO : i2c read error (fatal)
121  * -EBADMSG : frame was incorrect and discarded
122  * -ENOMEM : cannot allocate skb, frame dropped
123  */
124 static int st_nci_i2c_read(struct st_nci_i2c_phy *phy,
125 				 struct sk_buff **skb)
126 {
127 	int r;
128 	u8 len;
129 	u8 buf[ST_NCI_I2C_MAX_SIZE];
130 	struct i2c_client *client = phy->i2c_dev;
131 
132 	r = i2c_master_recv(client, buf, ST_NCI_I2C_MIN_SIZE);
133 	if (r < 0) {  /* Retry, chip was in standby */
134 		usleep_range(1000, 4000);
135 		r = i2c_master_recv(client, buf, ST_NCI_I2C_MIN_SIZE);
136 	}
137 
138 	if (r != ST_NCI_I2C_MIN_SIZE)
139 		return -EREMOTEIO;
140 
141 	len = be16_to_cpu(*(__be16 *) (buf + 2));
142 	if (len > ST_NCI_I2C_MAX_SIZE) {
143 		nfc_err(&client->dev, "invalid frame len\n");
144 		return -EBADMSG;
145 	}
146 
147 	*skb = alloc_skb(ST_NCI_I2C_MIN_SIZE + len, GFP_KERNEL);
148 	if (*skb == NULL)
149 		return -ENOMEM;
150 
151 	skb_reserve(*skb, ST_NCI_I2C_MIN_SIZE);
152 	skb_put(*skb, ST_NCI_I2C_MIN_SIZE);
153 	memcpy((*skb)->data, buf, ST_NCI_I2C_MIN_SIZE);
154 
155 	if (!len)
156 		return 0;
157 
158 	r = i2c_master_recv(client, buf, len);
159 	if (r != len) {
160 		kfree_skb(*skb);
161 		return -EREMOTEIO;
162 	}
163 
164 	skb_put(*skb, len);
165 	memcpy((*skb)->data + ST_NCI_I2C_MIN_SIZE, buf, len);
166 
167 	return 0;
168 }
169 
170 /*
171  * Reads an ndlc frame from the chip.
172  *
173  * On ST_NCI, IRQ goes in idle state when read starts.
174  */
175 static irqreturn_t st_nci_irq_thread_fn(int irq, void *phy_id)
176 {
177 	struct st_nci_i2c_phy *phy = phy_id;
178 	struct i2c_client *client;
179 	struct sk_buff *skb = NULL;
180 	int r;
181 
182 	if (!phy || !phy->ndlc || irq != phy->i2c_dev->irq) {
183 		WARN_ON_ONCE(1);
184 		return IRQ_NONE;
185 	}
186 
187 	client = phy->i2c_dev;
188 	dev_dbg(&client->dev, "IRQ\n");
189 
190 	if (phy->ndlc->hard_fault)
191 		return IRQ_HANDLED;
192 
193 	if (!phy->ndlc->powered) {
194 		st_nci_i2c_disable(phy);
195 		return IRQ_HANDLED;
196 	}
197 
198 	r = st_nci_i2c_read(phy, &skb);
199 	if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG)
200 		return IRQ_HANDLED;
201 
202 	ndlc_recv(phy->ndlc, skb);
203 
204 	return IRQ_HANDLED;
205 }
206 
207 static struct nfc_phy_ops i2c_phy_ops = {
208 	.write = st_nci_i2c_write,
209 	.enable = st_nci_i2c_enable,
210 	.disable = st_nci_i2c_disable,
211 };
212 
213 #ifdef CONFIG_OF
214 static int st_nci_i2c_of_request_resources(struct i2c_client *client)
215 {
216 	struct st_nci_i2c_phy *phy = i2c_get_clientdata(client);
217 	struct device_node *pp;
218 	int gpio;
219 	int r;
220 
221 	pp = client->dev.of_node;
222 	if (!pp)
223 		return -ENODEV;
224 
225 	/* Get GPIO from device tree */
226 	gpio = of_get_named_gpio(pp, "reset-gpios", 0);
227 	if (gpio < 0) {
228 		nfc_err(&client->dev,
229 			"Failed to retrieve reset-gpios from device tree\n");
230 		return gpio;
231 	}
232 
233 	/* GPIO request and configuration */
234 	r = devm_gpio_request_one(&client->dev, gpio,
235 				GPIOF_OUT_INIT_HIGH, "clf_reset");
236 	if (r) {
237 		nfc_err(&client->dev, "Failed to request reset pin\n");
238 		return r;
239 	}
240 	phy->gpio_reset = gpio;
241 
242 	phy->irq_polarity = irq_get_trigger_type(client->irq);
243 
244 	phy->se_status.is_ese_present =
245 				of_property_read_bool(pp, "ese-present");
246 	phy->se_status.is_uicc_present =
247 				of_property_read_bool(pp, "uicc-present");
248 
249 	return 0;
250 }
251 #else
252 static int st_nci_i2c_of_request_resources(struct i2c_client *client)
253 {
254 	return -ENODEV;
255 }
256 #endif
257 
258 static int st_nci_i2c_request_resources(struct i2c_client *client)
259 {
260 	struct st_nci_nfc_platform_data *pdata;
261 	struct st_nci_i2c_phy *phy = i2c_get_clientdata(client);
262 	int r;
263 
264 	pdata = client->dev.platform_data;
265 	if (pdata == NULL) {
266 		nfc_err(&client->dev, "No platform data\n");
267 		return -EINVAL;
268 	}
269 
270 	/* store for later use */
271 	phy->gpio_reset = pdata->gpio_reset;
272 	phy->irq_polarity = pdata->irq_polarity;
273 
274 	r = devm_gpio_request_one(&client->dev,
275 			phy->gpio_reset, GPIOF_OUT_INIT_HIGH, "clf_reset");
276 	if (r) {
277 		pr_err("%s : reset gpio_request failed\n", __FILE__);
278 		return r;
279 	}
280 
281 	phy->se_status.is_ese_present = pdata->is_ese_present;
282 	phy->se_status.is_uicc_present = pdata->is_uicc_present;
283 
284 	return 0;
285 }
286 
287 static int st_nci_i2c_probe(struct i2c_client *client,
288 				  const struct i2c_device_id *id)
289 {
290 	struct st_nci_i2c_phy *phy;
291 	struct st_nci_nfc_platform_data *pdata;
292 	int r;
293 
294 	dev_dbg(&client->dev, "%s\n", __func__);
295 	dev_dbg(&client->dev, "IRQ: %d\n", client->irq);
296 
297 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
298 		nfc_err(&client->dev, "Need I2C_FUNC_I2C\n");
299 		return -ENODEV;
300 	}
301 
302 	phy = devm_kzalloc(&client->dev, sizeof(struct st_nci_i2c_phy),
303 			   GFP_KERNEL);
304 	if (!phy)
305 		return -ENOMEM;
306 
307 	phy->i2c_dev = client;
308 
309 	i2c_set_clientdata(client, phy);
310 
311 	pdata = client->dev.platform_data;
312 	if (!pdata && client->dev.of_node) {
313 		r = st_nci_i2c_of_request_resources(client);
314 		if (r) {
315 			nfc_err(&client->dev, "No platform data\n");
316 			return r;
317 		}
318 	} else if (pdata) {
319 		r = st_nci_i2c_request_resources(client);
320 		if (r) {
321 			nfc_err(&client->dev,
322 				"Cannot get platform resources\n");
323 			return r;
324 		}
325 	} else {
326 		nfc_err(&client->dev,
327 			"st_nci platform resources not available\n");
328 		return -ENODEV;
329 	}
330 
331 	r = ndlc_probe(phy, &i2c_phy_ops, &client->dev,
332 			ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM,
333 			&phy->ndlc, &phy->se_status);
334 	if (r < 0) {
335 		nfc_err(&client->dev, "Unable to register ndlc layer\n");
336 		return r;
337 	}
338 
339 	phy->irq_active = true;
340 	r = devm_request_threaded_irq(&client->dev, client->irq, NULL,
341 				st_nci_irq_thread_fn,
342 				phy->irq_polarity | IRQF_ONESHOT,
343 				ST_NCI_DRIVER_NAME, phy);
344 	if (r < 0)
345 		nfc_err(&client->dev, "Unable to register IRQ handler\n");
346 
347 	return r;
348 }
349 
350 static int st_nci_i2c_remove(struct i2c_client *client)
351 {
352 	struct st_nci_i2c_phy *phy = i2c_get_clientdata(client);
353 
354 	dev_dbg(&client->dev, "%s\n", __func__);
355 
356 	ndlc_remove(phy->ndlc);
357 
358 	return 0;
359 }
360 
361 #ifdef CONFIG_OF
362 static const struct of_device_id of_st_nci_i2c_match[] = {
363 	{ .compatible = "st,st21nfcb-i2c", },
364 	{ .compatible = "st,st21nfcb_i2c", },
365 	{ .compatible = "st,st21nfcc-i2c", },
366 	{}
367 };
368 MODULE_DEVICE_TABLE(of, of_st_nci_i2c_match);
369 #endif
370 
371 static struct i2c_driver st_nci_i2c_driver = {
372 	.driver = {
373 		.owner = THIS_MODULE,
374 		.name = ST_NCI_I2C_DRIVER_NAME,
375 		.of_match_table = of_match_ptr(of_st_nci_i2c_match),
376 	},
377 	.probe = st_nci_i2c_probe,
378 	.id_table = st_nci_i2c_id_table,
379 	.remove = st_nci_i2c_remove,
380 };
381 
382 module_i2c_driver(st_nci_i2c_driver);
383 
384 MODULE_LICENSE("GPL");
385 MODULE_DESCRIPTION(DRIVER_DESC);
386