1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * SPI Link Layer for ST NCI 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/spi/spi.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#include <net/nfc/nci.h>
 18
 19#include "st-nci.h"
 20
 21#define DRIVER_DESC "NCI NFC driver for ST_NCI"
 22
 23/* ndlc header */
 24#define ST_NCI_FRAME_HEADROOM	1
 25#define ST_NCI_FRAME_TAILROOM	0
 26
 27#define ST_NCI_SPI_MIN_SIZE 4   /* PCB(1) + NCI Packet header(3) */
 28#define ST_NCI_SPI_MAX_SIZE 250 /* req 4.2.1 */
 29
 30#define ST_NCI_DRIVER_NAME "st_nci"
 31#define ST_NCI_SPI_DRIVER_NAME "st_nci_spi"
 32
 33struct st_nci_spi_phy {
 34	struct spi_device *spi_dev;
 35	struct llt_ndlc *ndlc;
 36
 37	bool irq_active;
 38
 39	struct gpio_desc *gpiod_reset;
 40
 41	struct st_nci_se_status se_status;
 42};
 43
 44static int st_nci_spi_enable(void *phy_id)
 45{
 46	struct st_nci_spi_phy *phy = phy_id;
 47
 48	gpiod_set_value(phy->gpiod_reset, 0);
 49	usleep_range(10000, 15000);
 50	gpiod_set_value(phy->gpiod_reset, 1);
 51	usleep_range(80000, 85000);
 52
 53	if (phy->ndlc->powered == 0 && phy->irq_active == 0) {
 54		enable_irq(phy->spi_dev->irq);
 55		phy->irq_active = true;
 56	}
 57
 58	return 0;
 59}
 60
 61static void st_nci_spi_disable(void *phy_id)
 62{
 63	struct st_nci_spi_phy *phy = phy_id;
 64
 65	disable_irq_nosync(phy->spi_dev->irq);
 66	phy->irq_active = false;
 67}
 68
 69/*
 70 * Writing a frame must not return the number of written bytes.
 71 * It must return either zero for success, or <0 for error.
 72 * In addition, it must not alter the skb
 73 */
 74static int st_nci_spi_write(void *phy_id, struct sk_buff *skb)
 75{
 76	int r;
 77	struct st_nci_spi_phy *phy = phy_id;
 78	struct spi_device *dev = phy->spi_dev;
 79	struct sk_buff *skb_rx;
 80	u8 buf[ST_NCI_SPI_MAX_SIZE + NCI_DATA_HDR_SIZE +
 81	       ST_NCI_FRAME_HEADROOM + ST_NCI_FRAME_TAILROOM];
 82	struct spi_transfer spi_xfer = {
 83		.tx_buf = skb->data,
 84		.rx_buf = buf,
 85		.len = skb->len,
 86	};
 87
 88	if (phy->ndlc->hard_fault != 0)
 89		return phy->ndlc->hard_fault;
 90
 91	r = spi_sync_transfer(dev, &spi_xfer, 1);
 92	/*
 93	 * We may have received some valuable data on miso line.
 94	 * Send them back in the ndlc state machine.
 95	 */
 96	if (!r) {
 97		skb_rx = alloc_skb(skb->len, GFP_KERNEL);
 98		if (!skb_rx) {
 99			r = -ENOMEM;
100			goto exit;
101		}
102
103		skb_put(skb_rx, skb->len);
104		memcpy(skb_rx->data, buf, skb->len);
105		ndlc_recv(phy->ndlc, skb_rx);
106	}
107
108exit:
109	return r;
110}
111
112/*
113 * Reads an ndlc frame and returns it in a newly allocated sk_buff.
114 * returns:
115 * 0 : if received frame is complete
116 * -EREMOTEIO : i2c read error (fatal)
117 * -EBADMSG : frame was incorrect and discarded
118 * -ENOMEM : cannot allocate skb, frame dropped
119 */
120static int st_nci_spi_read(struct st_nci_spi_phy *phy,
121			struct sk_buff **skb)
122{
123	int r;
124	u8 len;
125	u8 buf[ST_NCI_SPI_MAX_SIZE];
126	struct spi_device *dev = phy->spi_dev;
127	struct spi_transfer spi_xfer = {
128		.rx_buf = buf,
129		.len = ST_NCI_SPI_MIN_SIZE,
130	};
131
132	r = spi_sync_transfer(dev, &spi_xfer, 1);
133	if (r < 0)
134		return -EREMOTEIO;
135
136	len = be16_to_cpu(*(__be16 *) (buf + 2));
137	if (len > ST_NCI_SPI_MAX_SIZE) {
138		nfc_err(&dev->dev, "invalid frame len\n");
139		phy->ndlc->hard_fault = 1;
140		return -EBADMSG;
141	}
142
143	*skb = alloc_skb(ST_NCI_SPI_MIN_SIZE + len, GFP_KERNEL);
144	if (*skb == NULL)
145		return -ENOMEM;
146
147	skb_reserve(*skb, ST_NCI_SPI_MIN_SIZE);
148	skb_put(*skb, ST_NCI_SPI_MIN_SIZE);
149	memcpy((*skb)->data, buf, ST_NCI_SPI_MIN_SIZE);
150
151	if (!len)
152		return 0;
153
154	spi_xfer.len = len;
155	r = spi_sync_transfer(dev, &spi_xfer, 1);
156	if (r < 0) {
157		kfree_skb(*skb);
158		return -EREMOTEIO;
159	}
160
161	skb_put(*skb, len);
162	memcpy((*skb)->data + ST_NCI_SPI_MIN_SIZE, buf, len);
163
164	return 0;
165}
166
167/*
168 * Reads an ndlc frame from the chip.
169 *
170 * On ST21NFCB, IRQ goes in idle state when read starts.
171 */
172static irqreturn_t st_nci_irq_thread_fn(int irq, void *phy_id)
173{
174	struct st_nci_spi_phy *phy = phy_id;
175	struct spi_device *dev;
176	struct sk_buff *skb = NULL;
177	int r;
178
179	if (!phy || !phy->ndlc || irq != phy->spi_dev->irq) {
180		WARN_ON_ONCE(1);
181		return IRQ_NONE;
182	}
183
184	dev = phy->spi_dev;
185	dev_dbg(&dev->dev, "IRQ\n");
186
187	if (phy->ndlc->hard_fault)
188		return IRQ_HANDLED;
189
190	if (!phy->ndlc->powered) {
191		st_nci_spi_disable(phy);
192		return IRQ_HANDLED;
193	}
194
195	r = st_nci_spi_read(phy, &skb);
196	if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG)
197		return IRQ_HANDLED;
198
199	ndlc_recv(phy->ndlc, skb);
200
201	return IRQ_HANDLED;
202}
203
204static struct nfc_phy_ops spi_phy_ops = {
205	.write = st_nci_spi_write,
206	.enable = st_nci_spi_enable,
207	.disable = st_nci_spi_disable,
208};
209
210static const struct acpi_gpio_params reset_gpios = { 1, 0, false };
211
212static const struct acpi_gpio_mapping acpi_st_nci_gpios[] = {
213	{ "reset-gpios", &reset_gpios, 1 },
214	{},
215};
216
217static int st_nci_spi_probe(struct spi_device *dev)
218{
219	struct st_nci_spi_phy *phy;
220	int r;
221
222	dev_dbg(&dev->dev, "%s\n", __func__);
223	dev_dbg(&dev->dev, "IRQ: %d\n", dev->irq);
224
225	/* Check SPI platform functionnalities */
226	if (!dev) {
227		pr_debug("%s: dev is NULL. Device is not accessible.\n",
228			__func__);
229		return -ENODEV;
230	}
231
232	phy = devm_kzalloc(&dev->dev, sizeof(struct st_nci_spi_phy),
233			   GFP_KERNEL);
234	if (!phy)
235		return -ENOMEM;
236
237	phy->spi_dev = dev;
238
239	spi_set_drvdata(dev, phy);
240
241	r = devm_acpi_dev_add_driver_gpios(&dev->dev, acpi_st_nci_gpios);
242	if (r)
243		dev_dbg(&dev->dev, "Unable to add GPIO mapping table\n");
244
245	/* Get RESET GPIO */
246	phy->gpiod_reset = devm_gpiod_get(&dev->dev, "reset", GPIOD_OUT_HIGH);
247	if (IS_ERR(phy->gpiod_reset)) {
248		nfc_err(&dev->dev, "Unable to get RESET GPIO\n");
249		return PTR_ERR(phy->gpiod_reset);
250	}
251
252	phy->se_status.is_ese_present =
253			device_property_read_bool(&dev->dev, "ese-present");
254	phy->se_status.is_uicc_present =
255			device_property_read_bool(&dev->dev, "uicc-present");
256
257	r = ndlc_probe(phy, &spi_phy_ops, &dev->dev,
258			ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM,
259			&phy->ndlc, &phy->se_status);
260	if (r < 0) {
261		nfc_err(&dev->dev, "Unable to register ndlc layer\n");
262		return r;
263	}
264
265	phy->irq_active = true;
266	r = devm_request_threaded_irq(&dev->dev, dev->irq, NULL,
267				st_nci_irq_thread_fn,
268				IRQF_ONESHOT,
269				ST_NCI_SPI_DRIVER_NAME, phy);
270	if (r < 0)
271		nfc_err(&dev->dev, "Unable to register IRQ handler\n");
272
273	return r;
274}
275
276static int st_nci_spi_remove(struct spi_device *dev)
277{
278	struct st_nci_spi_phy *phy = spi_get_drvdata(dev);
279
280	dev_dbg(&dev->dev, "%s\n", __func__);
281
282	ndlc_remove(phy->ndlc);
283
284	return 0;
285}
286
287static struct spi_device_id st_nci_spi_id_table[] = {
288	{ST_NCI_SPI_DRIVER_NAME, 0},
289	{}
290};
291MODULE_DEVICE_TABLE(spi, st_nci_spi_id_table);
292
293static const struct acpi_device_id st_nci_spi_acpi_match[] = {
294	{"SMO2101", 0},
295	{}
296};
297MODULE_DEVICE_TABLE(acpi, st_nci_spi_acpi_match);
298
299static const struct of_device_id of_st_nci_spi_match[] = {
300	{ .compatible = "st,st21nfcb-spi", },
301	{}
302};
303MODULE_DEVICE_TABLE(of, of_st_nci_spi_match);
304
305static struct spi_driver st_nci_spi_driver = {
306	.driver = {
307		.name = ST_NCI_SPI_DRIVER_NAME,
308		.of_match_table = of_match_ptr(of_st_nci_spi_match),
309		.acpi_match_table = ACPI_PTR(st_nci_spi_acpi_match),
310	},
311	.probe = st_nci_spi_probe,
312	.id_table = st_nci_spi_id_table,
313	.remove = st_nci_spi_remove,
314};
315module_spi_driver(st_nci_spi_driver);
316
317MODULE_LICENSE("GPL");
318MODULE_DESCRIPTION(DRIVER_DESC);