2 * HCI based Driver for Inside Secure microread NFC Chip - i2c layer
4 * Copyright (C) 2013 Intel Corporation. All rights reserved.
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms and conditions of the GNU General Public License,
8 * version 2, as published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the
17 * Free Software Foundation, Inc.,
18 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
23 #include <linux/module.h>
24 #include <linux/i2c.h>
25 #include <linux/delay.h>
26 #include <linux/slab.h>
27 #include <linux/interrupt.h>
28 #include <linux/gpio.h>
30 #include <linux/nfc.h>
31 #include <net/nfc/hci.h>
32 #include <net/nfc/llc.h>
34 #include "microread.h"
36 #define MICROREAD_I2C_DRIVER_NAME "microread"
38 #define MICROREAD_I2C_FRAME_HEADROOM 1
39 #define MICROREAD_I2C_FRAME_TAILROOM 1
41 /* framing in HCI mode */
42 #define MICROREAD_I2C_LLC_LEN 1
43 #define MICROREAD_I2C_LLC_CRC 1
44 #define MICROREAD_I2C_LLC_LEN_CRC (MICROREAD_I2C_LLC_LEN + \
45 MICROREAD_I2C_LLC_CRC)
46 #define MICROREAD_I2C_LLC_MIN_SIZE (1 + MICROREAD_I2C_LLC_LEN_CRC)
47 #define MICROREAD_I2C_LLC_MAX_PAYLOAD 29
48 #define MICROREAD_I2C_LLC_MAX_SIZE (MICROREAD_I2C_LLC_LEN_CRC + 1 + \
49 MICROREAD_I2C_LLC_MAX_PAYLOAD)
51 struct microread_i2c_phy {
52 struct i2c_client *i2c_dev;
53 struct nfc_hci_dev *hdev;
58 * < 0 if hardware error occured (e.g. i2c err)
59 * and prevents normal operation.
63 #define I2C_DUMP_SKB(info, skb) \
65 pr_debug("%s:\n", info); \
66 print_hex_dump(KERN_DEBUG, "i2c: ", DUMP_PREFIX_OFFSET, \
67 16, 1, (skb)->data, (skb)->len, 0); \
70 static void microread_i2c_add_len_crc(struct sk_buff *skb)
77 *skb_push(skb, 1) = len;
79 for (i = 0; i < skb->len; i++)
80 crc = crc ^ skb->data[i];
82 *skb_put(skb, 1) = crc;
85 static void microread_i2c_remove_len_crc(struct sk_buff *skb)
87 skb_pull(skb, MICROREAD_I2C_FRAME_HEADROOM);
88 skb_trim(skb, MICROREAD_I2C_FRAME_TAILROOM);
91 static int check_crc(struct sk_buff *skb)
96 for (i = 0; i < skb->len - 1; i++)
97 crc = crc ^ skb->data[i];
99 if (crc != skb->data[skb->len-1]) {
100 pr_err("CRC error 0x%x != 0x%x\n", crc, skb->data[skb->len-1]);
101 pr_info("%s: BAD CRC\n", __func__);
108 static int microread_i2c_enable(void *phy_id)
113 static void microread_i2c_disable(void *phy_id)
118 static int microread_i2c_write(void *phy_id, struct sk_buff *skb)
121 struct microread_i2c_phy *phy = phy_id;
122 struct i2c_client *client = phy->i2c_dev;
124 if (phy->hard_fault != 0)
125 return phy->hard_fault;
127 usleep_range(3000, 6000);
129 microread_i2c_add_len_crc(skb);
131 I2C_DUMP_SKB("i2c frame written", skb);
133 r = i2c_master_send(client, skb->data, skb->len);
135 if (r == -EREMOTEIO) { /* Retry, chip was in standby */
136 usleep_range(6000, 10000);
137 r = i2c_master_send(client, skb->data, skb->len);
147 microread_i2c_remove_len_crc(skb);
153 static int microread_i2c_read(struct microread_i2c_phy *phy,
154 struct sk_buff **skb)
158 u8 tmp[MICROREAD_I2C_LLC_MAX_SIZE - 1];
159 struct i2c_client *client = phy->i2c_dev;
161 r = i2c_master_recv(client, &len, 1);
163 nfc_err(&client->dev, "cannot read len byte\n");
167 if ((len < MICROREAD_I2C_LLC_MIN_SIZE) ||
168 (len > MICROREAD_I2C_LLC_MAX_SIZE)) {
169 nfc_err(&client->dev, "invalid len byte\n");
174 *skb = alloc_skb(1 + len, GFP_KERNEL);
180 *skb_put(*skb, 1) = len;
182 r = i2c_master_recv(client, skb_put(*skb, len), len);
188 I2C_DUMP_SKB("cc frame read", *skb);
198 skb_trim(*skb, (*skb)->len - MICROREAD_I2C_FRAME_TAILROOM);
200 usleep_range(3000, 6000);
205 if (i2c_master_recv(client, tmp, sizeof(tmp)) < 0)
208 usleep_range(3000, 6000);
213 static irqreturn_t microread_i2c_irq_thread_fn(int irq, void *phy_id)
215 struct microread_i2c_phy *phy = phy_id;
216 struct i2c_client *client;
217 struct sk_buff *skb = NULL;
220 if (!phy || irq != phy->i2c_dev->irq) {
225 client = phy->i2c_dev;
227 if (phy->hard_fault != 0)
230 r = microread_i2c_read(phy, &skb);
231 if (r == -EREMOTEIO) {
234 nfc_hci_recv_frame(phy->hdev, NULL);
237 } else if ((r == -ENOMEM) || (r == -EBADMSG)) {
241 nfc_hci_recv_frame(phy->hdev, skb);
246 static struct nfc_phy_ops i2c_phy_ops = {
247 .write = microread_i2c_write,
248 .enable = microread_i2c_enable,
249 .disable = microread_i2c_disable,
252 static int microread_i2c_probe(struct i2c_client *client,
253 const struct i2c_device_id *id)
255 struct microread_i2c_phy *phy;
256 struct microread_nfc_platform_data *pdata =
257 dev_get_platdata(&client->dev);
260 dev_dbg(&client->dev, "client %p\n", client);
263 nfc_err(&client->dev, "client %p: missing platform data\n",
268 phy = devm_kzalloc(&client->dev, sizeof(struct microread_i2c_phy),
273 i2c_set_clientdata(client, phy);
274 phy->i2c_dev = client;
276 r = request_threaded_irq(client->irq, NULL, microread_i2c_irq_thread_fn,
277 IRQF_TRIGGER_RISING | IRQF_ONESHOT,
278 MICROREAD_I2C_DRIVER_NAME, phy);
280 nfc_err(&client->dev, "Unable to register IRQ handler\n");
284 r = microread_probe(phy, &i2c_phy_ops, LLC_SHDLC_NAME,
285 MICROREAD_I2C_FRAME_HEADROOM,
286 MICROREAD_I2C_FRAME_TAILROOM,
287 MICROREAD_I2C_LLC_MAX_PAYLOAD, &phy->hdev);
291 nfc_info(&client->dev, "Probed");
296 free_irq(client->irq, phy);
301 static int microread_i2c_remove(struct i2c_client *client)
303 struct microread_i2c_phy *phy = i2c_get_clientdata(client);
305 microread_remove(phy->hdev);
307 free_irq(client->irq, phy);
312 static struct i2c_device_id microread_i2c_id[] = {
313 { MICROREAD_I2C_DRIVER_NAME, 0},
316 MODULE_DEVICE_TABLE(i2c, microread_i2c_id);
318 static struct i2c_driver microread_i2c_driver = {
320 .name = MICROREAD_I2C_DRIVER_NAME,
322 .probe = microread_i2c_probe,
323 .remove = microread_i2c_remove,
324 .id_table = microread_i2c_id,
327 module_i2c_driver(microread_i2c_driver);
329 MODULE_LICENSE("GPL");
330 MODULE_DESCRIPTION(DRIVER_DESC);