1/* -------------------------------------------------------------------------
2 * Copyright (C) 2014-2016, Intel Corporation
3 *
4 *  This program is free software; you can redistribute it and/or modify
5 *  it under the terms of the GNU General Public License as published by
6 *  the Free Software Foundation; either version 2 of the License, or
7 *  (at your option) any later version.
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 */
15
16#include <linux/module.h>
17#include <linux/acpi.h>
18#include <linux/i2c.h>
19#include <linux/interrupt.h>
20#include <linux/nfc.h>
21#include <linux/delay.h>
22#include <linux/gpio/consumer.h>
23#include <net/nfc/nfc.h>
24#include <net/nfc/nci_core.h>
25
26#include "fdp.h"
27
28#define FDP_I2C_DRIVER_NAME	"fdp_nci_i2c"
29
30#define FDP_DP_POWER_GPIO_NAME	"power"
31#define FDP_DP_CLOCK_TYPE_NAME	"clock-type"
32#define FDP_DP_CLOCK_FREQ_NAME	"clock-freq"
33#define FDP_DP_FW_VSC_CFG_NAME	"fw-vsc-cfg"
34
35#define FDP_FRAME_HEADROOM	2
36#define FDP_FRAME_TAILROOM	1
37
38#define FDP_NCI_I2C_MIN_PAYLOAD	5
39#define FDP_NCI_I2C_MAX_PAYLOAD	261
40
41#define FDP_POWER_OFF		0
42#define FDP_POWER_ON		1
43
44#define fdp_nci_i2c_dump_skb(dev, prefix, skb)				\
45	print_hex_dump(KERN_DEBUG, prefix": ", DUMP_PREFIX_OFFSET,	\
46		       16, 1, (skb)->data, (skb)->len, 0)
47
48static void fdp_nci_i2c_reset(struct fdp_i2c_phy *phy)
49{
50	/* Reset RST/WakeUP for at least 100 micro-second */
51	gpiod_set_value_cansleep(phy->power_gpio, FDP_POWER_OFF);
52	usleep_range(1000, 4000);
53	gpiod_set_value_cansleep(phy->power_gpio, FDP_POWER_ON);
54	usleep_range(10000, 14000);
55}
56
57static int fdp_nci_i2c_enable(void *phy_id)
58{
59	struct fdp_i2c_phy *phy = phy_id;
60
61	dev_dbg(&phy->i2c_dev->dev, "%s\n", __func__);
62	fdp_nci_i2c_reset(phy);
63
64	return 0;
65}
66
67static void fdp_nci_i2c_disable(void *phy_id)
68{
69	struct fdp_i2c_phy *phy = phy_id;
70
71	dev_dbg(&phy->i2c_dev->dev, "%s\n", __func__);
72	fdp_nci_i2c_reset(phy);
73}
74
75static void fdp_nci_i2c_add_len_lrc(struct sk_buff *skb)
76{
77	u8 lrc = 0;
78	u16 len, i;
79
80	/* Add length header */
81	len = skb->len;
82	*skb_push(skb, 1) = len & 0xff;
83	*skb_push(skb, 1) = len >> 8;
84
85	/* Compute and add lrc */
86	for (i = 0; i < len + 2; i++)
87		lrc ^= skb->data[i];
88
89	*skb_put(skb, 1) = lrc;
90}
91
92static void fdp_nci_i2c_remove_len_lrc(struct sk_buff *skb)
93{
94	skb_pull(skb, FDP_FRAME_HEADROOM);
95	skb_trim(skb, skb->len - FDP_FRAME_TAILROOM);
96}
97
98static int fdp_nci_i2c_write(void *phy_id, struct sk_buff *skb)
99{
100	struct fdp_i2c_phy *phy = phy_id;
101	struct i2c_client *client = phy->i2c_dev;
102	int r;
103
104	if (phy->hard_fault != 0)
105		return phy->hard_fault;
106
107	fdp_nci_i2c_add_len_lrc(skb);
108	fdp_nci_i2c_dump_skb(&client->dev, "fdp_wr", skb);
109
110	r = i2c_master_send(client, skb->data, skb->len);
111	if (r == -EREMOTEIO) {  /* Retry, chip was in standby */
112		usleep_range(1000, 4000);
113		r = i2c_master_send(client, skb->data, skb->len);
114	}
115
116	if (r < 0 || r != skb->len)
117		dev_dbg(&client->dev, "%s: error err=%d len=%d\n",
118			__func__, r, skb->len);
119
120	if (r >= 0) {
121		if (r != skb->len) {
122			phy->hard_fault = r;
123			r = -EREMOTEIO;
124		} else {
125			r = 0;
126		}
127	}
128
129	fdp_nci_i2c_remove_len_lrc(skb);
130
131	return r;
132}
133
134static struct nfc_phy_ops i2c_phy_ops = {
135	.write = fdp_nci_i2c_write,
136	.enable = fdp_nci_i2c_enable,
137	.disable = fdp_nci_i2c_disable,
138};
139
140static int fdp_nci_i2c_read(struct fdp_i2c_phy *phy, struct sk_buff **skb)
141{
142	int r, len;
143	u8 tmp[FDP_NCI_I2C_MAX_PAYLOAD], lrc, k;
144	u16 i;
145	struct i2c_client *client = phy->i2c_dev;
146
147	*skb = NULL;
148
149	/* Read the length packet and the data packet */
150	for (k = 0; k < 2; k++) {
151
152		len = phy->next_read_size;
153
154		r = i2c_master_recv(client, tmp, len);
155		if (r != len) {
156			dev_dbg(&client->dev, "%s: i2c recv err: %d\n",
157				__func__, r);
158			goto flush;
159		}
160
161		/* Check packet integruty */
162		for (lrc = i = 0; i < r; i++)
163			lrc ^= tmp[i];
164
165		/*
166		 * LRC check failed. This may due to transmission error or
167		 * desynchronization between driver and FDP. Drop the paquet
168		 * and force resynchronization
169		 */
170		if (lrc) {
171			dev_dbg(&client->dev, "%s: corrupted packet\n",
172				__func__);
173			phy->next_read_size = 5;
174			goto flush;
175		}
176
177		/* Packet that contains a length */
178		if (tmp[0] == 0 && tmp[1] == 0) {
179			phy->next_read_size = (tmp[2] << 8) + tmp[3] + 3;
180		} else {
181			phy->next_read_size = FDP_NCI_I2C_MIN_PAYLOAD;
182
183			*skb = alloc_skb(len, GFP_KERNEL);
184			if (*skb == NULL) {
185				r = -ENOMEM;
186				goto flush;
187			}
188
189			memcpy(skb_put(*skb, len), tmp, len);
190			fdp_nci_i2c_dump_skb(&client->dev, "fdp_rd", *skb);
191
192			fdp_nci_i2c_remove_len_lrc(*skb);
193		}
194	}
195
196	return 0;
197
198flush:
199	/* Flush the remaining data */
200	if (i2c_master_recv(client, tmp, sizeof(tmp)) < 0)
201		r = -EREMOTEIO;
202
203	return r;
204}
205
206static irqreturn_t fdp_nci_i2c_irq_thread_fn(int irq, void *phy_id)
207{
208	struct fdp_i2c_phy *phy = phy_id;
209	struct i2c_client *client;
210	struct sk_buff *skb;
211	int r;
212
213	client = phy->i2c_dev;
214	dev_dbg(&client->dev, "%s\n", __func__);
215
216	if (!phy || irq != phy->i2c_dev->irq) {
217		WARN_ON_ONCE(1);
218		return IRQ_NONE;
219	}
220
221	r = fdp_nci_i2c_read(phy, &skb);
222
223	if (r == -EREMOTEIO)
224		return IRQ_HANDLED;
225	else if (r == -ENOMEM || r == -EBADMSG)
226		return IRQ_HANDLED;
227
228	if (skb != NULL)
229		fdp_nci_recv_frame(phy->ndev, skb);
230
231	return IRQ_HANDLED;
232}
233
234static void fdp_nci_i2c_read_device_properties(struct device *dev,
235					       u8 *clock_type, u32 *clock_freq,
236					       u8 **fw_vsc_cfg)
237{
238	int r;
239	u8 len;
240
241	r = device_property_read_u8(dev, FDP_DP_CLOCK_TYPE_NAME, clock_type);
242	if (r) {
243		dev_dbg(dev, "Using default clock type");
244		*clock_type = 0;
245	}
246
247	r = device_property_read_u32(dev, FDP_DP_CLOCK_FREQ_NAME, clock_freq);
248	if (r) {
249		dev_dbg(dev, "Using default clock frequency\n");
250		*clock_freq = 26000;
251	}
252
253	if (device_property_present(dev, FDP_DP_FW_VSC_CFG_NAME)) {
254		r = device_property_read_u8(dev, FDP_DP_FW_VSC_CFG_NAME,
255					    &len);
256
257		if (r || len <= 0)
258			goto vsc_read_err;
259
260		/* Add 1 to the length to inclue the length byte itself */
261		len++;
262
263		*fw_vsc_cfg = devm_kmalloc(dev,
264					   len * sizeof(**fw_vsc_cfg),
265					   GFP_KERNEL);
266
267		r = device_property_read_u8_array(dev, FDP_DP_FW_VSC_CFG_NAME,
268						  *fw_vsc_cfg, len);
269
270		if (r) {
271			devm_kfree(dev, fw_vsc_cfg);
272			goto vsc_read_err;
273		}
274	} else {
275vsc_read_err:
276		dev_dbg(dev, "FW vendor specific commands not present\n");
277		*fw_vsc_cfg = NULL;
278	}
279
280	dev_dbg(dev, "Clock type: %d, clock frequency: %d, VSC: %s",
281		*clock_type, *clock_freq, *fw_vsc_cfg != NULL ? "yes" : "no");
282}
283
284static int fdp_nci_i2c_probe(struct i2c_client *client,
285			     const struct i2c_device_id *id)
286{
287	struct fdp_i2c_phy *phy;
288	struct device *dev = &client->dev;
289	u8 *fw_vsc_cfg;
290	u8 clock_type;
291	u32 clock_freq;
292	int r = 0;
293
294	dev_dbg(dev, "%s\n", __func__);
295
296	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
297		nfc_err(dev, "No I2C_FUNC_I2C support\n");
298		return -ENODEV;
299	}
300
301	phy = devm_kzalloc(dev, sizeof(struct fdp_i2c_phy),
302			   GFP_KERNEL);
303	if (!phy)
304		return -ENOMEM;
305
306	phy->i2c_dev = client;
307	phy->next_read_size = FDP_NCI_I2C_MIN_PAYLOAD;
308	i2c_set_clientdata(client, phy);
309
310	/* Checking if we have an irq */
311	if (client->irq <= 0) {
312		dev_err(dev, "IRQ not present\n");
313		return -ENODEV;
314	}
315
316	r = request_threaded_irq(client->irq, NULL, fdp_nci_i2c_irq_thread_fn,
317				 IRQF_TRIGGER_RISING | IRQF_ONESHOT,
318				 FDP_I2C_DRIVER_NAME, phy);
319
320	if (r < 0) {
321		nfc_err(&client->dev, "Unable to register IRQ handler\n");
322		return r;
323	}
324
325	/* Requesting the power gpio */
326	phy->power_gpio = devm_gpiod_get(dev, FDP_DP_POWER_GPIO_NAME,
327					 GPIOD_OUT_LOW);
328
329	if (IS_ERR(phy->power_gpio)) {
330		nfc_err(dev, "Power GPIO request failed\n");
331		return PTR_ERR(phy->power_gpio);
332	}
333
334	/* read device properties to get the clock and production settings */
335	fdp_nci_i2c_read_device_properties(dev, &clock_type, &clock_freq,
336					   &fw_vsc_cfg);
337
338	/* Call the NFC specific probe function */
339	r = fdp_nci_probe(phy, &i2c_phy_ops, &phy->ndev,
340			  FDP_FRAME_HEADROOM, FDP_FRAME_TAILROOM,
341			  clock_type, clock_freq, fw_vsc_cfg);
342	if (r < 0) {
343		nfc_err(dev, "NCI probing error\n");
344		return r;
345	}
346
347	dev_dbg(dev, "I2C driver loaded\n");
348	return 0;
349}
350
351static int fdp_nci_i2c_remove(struct i2c_client *client)
352{
353	struct fdp_i2c_phy *phy = i2c_get_clientdata(client);
354
355	dev_dbg(&client->dev, "%s\n", __func__);
356
357	fdp_nci_remove(phy->ndev);
358	fdp_nci_i2c_disable(phy);
359
360	return 0;
361}
362
363static struct i2c_device_id fdp_nci_i2c_id_table[] = {
364	{"int339a", 0},
365	{}
366};
367MODULE_DEVICE_TABLE(i2c, fdp_nci_i2c_id_table);
368
369static const struct acpi_device_id fdp_nci_i2c_acpi_match[] = {
370	{"INT339A", 0},
371	{}
372};
373MODULE_DEVICE_TABLE(acpi, fdp_nci_i2c_acpi_match);
374
375static struct i2c_driver fdp_nci_i2c_driver = {
376	.driver = {
377		   .name = FDP_I2C_DRIVER_NAME,
378		   .acpi_match_table = ACPI_PTR(fdp_nci_i2c_acpi_match),
379		  },
380	.id_table = fdp_nci_i2c_id_table,
381	.probe = fdp_nci_i2c_probe,
382	.remove = fdp_nci_i2c_remove,
383};
384module_i2c_driver(fdp_nci_i2c_driver);
385
386MODULE_LICENSE("GPL");
387MODULE_DESCRIPTION("I2C driver for Intel Fields Peak NFC controller");
388MODULE_AUTHOR("Robert Dolca <robert.dolca@intel.com>");
389