1// SPDX-License-Identifier: GPL-2.0-or-later
2/* -------------------------------------------------------------------------
3 * Copyright (C) 2014-2016, Intel Corporation
4 *
5 * -------------------------------------------------------------------------
6 */
7
8#include <linux/module.h>
9#include <linux/acpi.h>
10#include <linux/i2c.h>
11#include <linux/interrupt.h>
12#include <linux/nfc.h>
13#include <linux/delay.h>
14#include <linux/gpio/consumer.h>
15#include <net/nfc/nfc.h>
16#include <net/nfc/nci_core.h>
17
18#include "fdp.h"
19
20#define FDP_I2C_DRIVER_NAME	"fdp_nci_i2c"
21
22#define FDP_DP_CLOCK_TYPE_NAME	"clock-type"
23#define FDP_DP_CLOCK_FREQ_NAME	"clock-freq"
24#define FDP_DP_FW_VSC_CFG_NAME	"fw-vsc-cfg"
25
26#define FDP_FRAME_HEADROOM	2
27#define FDP_FRAME_TAILROOM	1
28
29#define FDP_NCI_I2C_MIN_PAYLOAD	5
30#define FDP_NCI_I2C_MAX_PAYLOAD	261
31
32#define FDP_POWER_OFF		0
33#define FDP_POWER_ON		1
34
35#define fdp_nci_i2c_dump_skb(dev, prefix, skb)				\
36	print_hex_dump(KERN_DEBUG, prefix": ", DUMP_PREFIX_OFFSET,	\
37		       16, 1, (skb)->data, (skb)->len, 0)
38
39static void fdp_nci_i2c_reset(const struct fdp_i2c_phy *phy)
40{
41	/* Reset RST/WakeUP for at least 100 micro-second */
42	gpiod_set_value_cansleep(phy->power_gpio, FDP_POWER_OFF);
43	usleep_range(1000, 4000);
44	gpiod_set_value_cansleep(phy->power_gpio, FDP_POWER_ON);
45	usleep_range(10000, 14000);
46}
47
48static int fdp_nci_i2c_enable(void *phy_id)
49{
50	const struct fdp_i2c_phy *phy = phy_id;
51
52	fdp_nci_i2c_reset(phy);
53
54	return 0;
55}
56
57static void fdp_nci_i2c_disable(void *phy_id)
58{
59	const struct fdp_i2c_phy *phy = phy_id;
60
61	fdp_nci_i2c_reset(phy);
62}
63
64static void fdp_nci_i2c_add_len_lrc(struct sk_buff *skb)
65{
66	u8 lrc = 0;
67	u16 len, i;
68
69	/* Add length header */
70	len = skb->len;
71	*(u8 *)skb_push(skb, 1) = len & 0xff;
72	*(u8 *)skb_push(skb, 1) = len >> 8;
73
74	/* Compute and add lrc */
75	for (i = 0; i < len + 2; i++)
76		lrc ^= skb->data[i];
77
78	skb_put_u8(skb, lrc);
79}
80
81static void fdp_nci_i2c_remove_len_lrc(struct sk_buff *skb)
82{
83	skb_pull(skb, FDP_FRAME_HEADROOM);
84	skb_trim(skb, skb->len - FDP_FRAME_TAILROOM);
85}
86
87static int fdp_nci_i2c_write(void *phy_id, struct sk_buff *skb)
88{
89	struct fdp_i2c_phy *phy = phy_id;
90	struct i2c_client *client = phy->i2c_dev;
91	int r;
92
93	if (phy->hard_fault != 0)
94		return phy->hard_fault;
95
96	fdp_nci_i2c_add_len_lrc(skb);
97	fdp_nci_i2c_dump_skb(&client->dev, "fdp_wr", skb);
98
99	r = i2c_master_send(client, skb->data, skb->len);
100	if (r == -EREMOTEIO) {  /* Retry, chip was in standby */
101		usleep_range(1000, 4000);
102		r = i2c_master_send(client, skb->data, skb->len);
103	}
104
105	if (r < 0 || r != skb->len)
106		dev_dbg(&client->dev, "%s: error err=%d len=%d\n",
107			__func__, r, skb->len);
108
109	if (r >= 0) {
110		if (r != skb->len) {
111			phy->hard_fault = r;
112			r = -EREMOTEIO;
113		} else {
114			r = 0;
115		}
116	}
117
118	fdp_nci_i2c_remove_len_lrc(skb);
119
120	return r;
121}
122
123static const struct nfc_phy_ops i2c_phy_ops = {
124	.write = fdp_nci_i2c_write,
125	.enable = fdp_nci_i2c_enable,
126	.disable = fdp_nci_i2c_disable,
127};
128
129static int fdp_nci_i2c_read(struct fdp_i2c_phy *phy, struct sk_buff **skb)
130{
131	int r, len;
132	u8 tmp[FDP_NCI_I2C_MAX_PAYLOAD], lrc, k;
133	u16 i;
134	struct i2c_client *client = phy->i2c_dev;
135
136	*skb = NULL;
137
138	/* Read the length packet and the data packet */
139	for (k = 0; k < 2; k++) {
140
141		len = phy->next_read_size;
142
143		r = i2c_master_recv(client, tmp, len);
144		if (r != len) {
145			dev_dbg(&client->dev, "%s: i2c recv err: %d\n",
146				__func__, r);
147			goto flush;
148		}
149
150		/* Check packet integruty */
151		for (lrc = i = 0; i < r; i++)
152			lrc ^= tmp[i];
153
154		/*
155		 * LRC check failed. This may due to transmission error or
156		 * desynchronization between driver and FDP. Drop the packet
157		 * and force resynchronization
158		 */
159		if (lrc) {
160			dev_dbg(&client->dev, "%s: corrupted packet\n",
161				__func__);
162			phy->next_read_size = 5;
163			goto flush;
164		}
165
166		/* Packet that contains a length */
167		if (tmp[0] == 0 && tmp[1] == 0) {
168			phy->next_read_size = (tmp[2] << 8) + tmp[3] + 3;
169		} else {
170			phy->next_read_size = FDP_NCI_I2C_MIN_PAYLOAD;
171
172			*skb = alloc_skb(len, GFP_KERNEL);
173			if (*skb == NULL) {
174				r = -ENOMEM;
175				goto flush;
176			}
177
178			skb_put_data(*skb, tmp, len);
179			fdp_nci_i2c_dump_skb(&client->dev, "fdp_rd", *skb);
180
181			fdp_nci_i2c_remove_len_lrc(*skb);
182		}
183	}
184
185	return 0;
186
187flush:
188	/* Flush the remaining data */
189	if (i2c_master_recv(client, tmp, sizeof(tmp)) < 0)
190		r = -EREMOTEIO;
191
192	return r;
193}
194
195static irqreturn_t fdp_nci_i2c_irq_thread_fn(int irq, void *phy_id)
196{
197	struct fdp_i2c_phy *phy = phy_id;
198	struct sk_buff *skb;
199	int r;
200
201	if (!phy || irq != phy->i2c_dev->irq) {
202		WARN_ON_ONCE(1);
203		return IRQ_NONE;
204	}
205
206	r = fdp_nci_i2c_read(phy, &skb);
207
208	if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG)
209		return IRQ_HANDLED;
210
211	if (skb != NULL)
212		nci_recv_frame(phy->ndev, skb);
213
214	return IRQ_HANDLED;
215}
216
217static void fdp_nci_i2c_read_device_properties(struct device *dev,
218					       u8 *clock_type, u32 *clock_freq,
219					       u8 **fw_vsc_cfg)
220{
221	int r;
222	u8 len;
223
224	r = device_property_read_u8(dev, FDP_DP_CLOCK_TYPE_NAME, clock_type);
225	if (r) {
226		dev_dbg(dev, "Using default clock type");
227		*clock_type = 0;
228	}
229
230	r = device_property_read_u32(dev, FDP_DP_CLOCK_FREQ_NAME, clock_freq);
231	if (r) {
232		dev_dbg(dev, "Using default clock frequency\n");
233		*clock_freq = 26000;
234	}
235
236	if (device_property_present(dev, FDP_DP_FW_VSC_CFG_NAME)) {
237		r = device_property_read_u8(dev, FDP_DP_FW_VSC_CFG_NAME,
238					    &len);
239
240		if (r || len <= 0)
241			goto vsc_read_err;
242
243		/* Add 1 to the length to inclue the length byte itself */
244		len++;
245
246		*fw_vsc_cfg = devm_kmalloc_array(dev,
247					   len, sizeof(**fw_vsc_cfg),
248					   GFP_KERNEL);
249
250		if (!*fw_vsc_cfg)
251			goto alloc_err;
252
253		r = device_property_read_u8_array(dev, FDP_DP_FW_VSC_CFG_NAME,
254						  *fw_vsc_cfg, len);
255
256		if (r) {
257			devm_kfree(dev, *fw_vsc_cfg);
258			goto vsc_read_err;
259		}
260	} else {
261vsc_read_err:
262		dev_dbg(dev, "FW vendor specific commands not present\n");
263		*fw_vsc_cfg = NULL;
264	}
265
266alloc_err:
267	dev_dbg(dev, "Clock type: %d, clock frequency: %d, VSC: %s",
268		*clock_type, *clock_freq, *fw_vsc_cfg != NULL ? "yes" : "no");
269}
270
271static const struct acpi_gpio_params power_gpios = { 0, 0, false };
272
273static const struct acpi_gpio_mapping acpi_fdp_gpios[] = {
274	{ "power-gpios", &power_gpios, 1 },
275	{},
276};
277
278static int fdp_nci_i2c_probe(struct i2c_client *client)
279{
280	struct fdp_i2c_phy *phy;
281	struct device *dev = &client->dev;
282	u8 *fw_vsc_cfg;
283	u8 clock_type;
284	u32 clock_freq;
285	int r = 0;
286
287	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
288		nfc_err(dev, "No I2C_FUNC_I2C support\n");
289		return -ENODEV;
290	}
291
292	/* Checking if we have an irq */
293	if (client->irq <= 0) {
294		nfc_err(dev, "IRQ not present\n");
295		return -ENODEV;
296	}
297
298	phy = devm_kzalloc(dev, sizeof(struct fdp_i2c_phy), GFP_KERNEL);
299	if (!phy)
300		return -ENOMEM;
301
302	phy->i2c_dev = client;
303	phy->next_read_size = FDP_NCI_I2C_MIN_PAYLOAD;
304	i2c_set_clientdata(client, phy);
305
306	r = devm_request_threaded_irq(dev, client->irq,
307				      NULL, fdp_nci_i2c_irq_thread_fn,
308				      IRQF_TRIGGER_RISING | IRQF_ONESHOT,
309				      FDP_I2C_DRIVER_NAME, phy);
310
311	if (r < 0) {
312		nfc_err(&client->dev, "Unable to register IRQ handler\n");
313		return r;
314	}
315
316	r = devm_acpi_dev_add_driver_gpios(dev, acpi_fdp_gpios);
317	if (r)
318		dev_dbg(dev, "Unable to add GPIO mapping table\n");
319
320	/* Requesting the power gpio */
321	phy->power_gpio = devm_gpiod_get(dev, "power", GPIOD_OUT_LOW);
322	if (IS_ERR(phy->power_gpio)) {
323		nfc_err(dev, "Power GPIO request failed\n");
324		return PTR_ERR(phy->power_gpio);
325	}
326
327	/* read device properties to get the clock and production settings */
328	fdp_nci_i2c_read_device_properties(dev, &clock_type, &clock_freq,
329					   &fw_vsc_cfg);
330
331	/* Call the NFC specific probe function */
332	r = fdp_nci_probe(phy, &i2c_phy_ops, &phy->ndev,
333			  FDP_FRAME_HEADROOM, FDP_FRAME_TAILROOM,
334			  clock_type, clock_freq, fw_vsc_cfg);
335	if (r < 0) {
336		nfc_err(dev, "NCI probing error\n");
337		return r;
338	}
339
340	return 0;
341}
342
343static void fdp_nci_i2c_remove(struct i2c_client *client)
344{
345	struct fdp_i2c_phy *phy = i2c_get_clientdata(client);
346
347	fdp_nci_remove(phy->ndev);
348	fdp_nci_i2c_disable(phy);
349}
350
351static const struct acpi_device_id fdp_nci_i2c_acpi_match[] = {
352	{"INT339A", 0},
353	{}
354};
355MODULE_DEVICE_TABLE(acpi, fdp_nci_i2c_acpi_match);
356
357static struct i2c_driver fdp_nci_i2c_driver = {
358	.driver = {
359		   .name = FDP_I2C_DRIVER_NAME,
360		   .acpi_match_table = fdp_nci_i2c_acpi_match,
361		  },
362	.probe = fdp_nci_i2c_probe,
363	.remove = fdp_nci_i2c_remove,
364};
365module_i2c_driver(fdp_nci_i2c_driver);
366
367MODULE_LICENSE("GPL");
368MODULE_DESCRIPTION("I2C driver for Intel Fields Peak NFC controller");
369MODULE_AUTHOR("Robert Dolca <robert.dolca@intel.com>");
370