drivers/nfc/pn533/i2c.c

   1 /*
   2  * Driver for NXP PN533 NFC Chip - I2C transport layer
   3  *
   4  * Copyright (C) 2011 Instituto Nokia de Tecnologia
   5  * Copyright (C) 2012-2013 Tieto Poland
   6  * Copyright (C) 2016 HALE electronic
   7  *
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  21  */
  22
  23 #include <linux/device.h>
  24 #include <linux/kernel.h>
  25 #include <linux/module.h>
  26 #include <linux/slab.h>
  27 #include <linux/i2c.h>
  28 #include <linux/nfc.h>
  29 #include <linux/netdevice.h>
  30 #include <linux/interrupt.h>
  31 #include <net/nfc/nfc.h>
  32 #include "pn533.h"
  33
  34 #define VERSION "0.1"
  35
  36 #define PN533_I2C_DRIVER_NAME "pn533_i2c"
  37
  38 struct pn533_i2c_phy {
  39         struct i2c_client *i2c_dev;
  40         struct pn533 *priv;
  41
  42         bool aborted;
  43
  44         int hard_fault;         /*
  45                                  * < 0 if hardware error occurred (e.g. i2c err)
  46                                  * and prevents normal operation.
  47                                  */
  48 };
  49
  50 static int pn533_i2c_send_ack(struct pn533 *dev, gfp_t flags)
  51 {
  52         struct pn533_i2c_phy *phy = dev->phy;
  53         struct i2c_client *client = phy->i2c_dev;
  54         u8 ack[6] = {0x00, 0x00, 0xff, 0x00, 0xff, 0x00};
  55         /* spec 6.2.1.3:  Preamble, SoPC (2), ACK Code (2), Postamble */
  56         int rc;
  57
  58         rc = i2c_master_send(client, ack, 6);
  59
  60         return rc;
  61 }
  62
  63 static int pn533_i2c_send_frame(struct pn533 *dev,
  64                                 struct sk_buff *out)
  65 {
  66         struct pn533_i2c_phy *phy = dev->phy;
  67         struct i2c_client *client = phy->i2c_dev;
  68         int rc;
  69
  70         if (phy->hard_fault != 0)
  71                 return phy->hard_fault;
  72
  73         if (phy->priv == NULL)
  74                 phy->priv = dev;
  75
  76         phy->aborted = false;
  77
  78         print_hex_dump_debug("PN533_i2c TX: ", DUMP_PREFIX_NONE, 16, 1,
  79                              out->data, out->len, false);
  80
  81         rc = i2c_master_send(client, out->data, out->len);
  82
  83         if (rc == -EREMOTEIO) { /* Retry, chip was in power down */
  84                 usleep_range(6000, 10000);
  85                 rc = i2c_master_send(client, out->data, out->len);
  86         }
  87
  88         if (rc >= 0) {
  89                 if (rc != out->len)
  90                         rc = -EREMOTEIO;
  91                 else
  92                         rc = 0;
  93         }
  94
  95         return rc;
  96 }
  97
  98 static void pn533_i2c_abort_cmd(struct pn533 *dev, gfp_t flags)
  99 {
 100         struct pn533_i2c_phy *phy = dev->phy;
 101
 102         phy->aborted = true;
 103
 104         /* An ack will cancel the last issued command */
 105         pn533_i2c_send_ack(dev, flags);
 106
 107         /* schedule cmd_complete_work to finish current command execution */
 108         pn533_recv_frame(phy->priv, NULL, -ENOENT);
 109 }
 110
 111 static int pn533_i2c_read(struct pn533_i2c_phy *phy, struct sk_buff **skb)
 112 {
 113         struct i2c_client *client = phy->i2c_dev;
 114         int len = PN533_EXT_FRAME_HEADER_LEN +
 115                   PN533_STD_FRAME_MAX_PAYLOAD_LEN +
 116                   PN533_STD_FRAME_TAIL_LEN + 1;
 117         int r;
 118
 119         *skb = alloc_skb(len, GFP_KERNEL);
 120         if (*skb == NULL)
 121                 return -ENOMEM;
 122
 123         r = i2c_master_recv(client, skb_put(*skb, len), len);
 124         if (r != len) {
 125                 nfc_err(&client->dev, "cannot read. r=%d len=%d\n", r, len);
 126                 kfree_skb(*skb);
 127                 return -EREMOTEIO;
 128         }
 129
 130         if (!((*skb)->data[0] & 0x01)) {
 131                 nfc_err(&client->dev, "READY flag not set");
 132                 kfree_skb(*skb);
 133                 return -EBUSY;
 134         }
 135
 136         /* remove READY byte */
 137         skb_pull(*skb, 1);
 138         /* trim to frame size */
 139         skb_trim(*skb, phy->priv->ops->rx_frame_size((*skb)->data));
 140
 141         return 0;
 142 }
 143
 144 static irqreturn_t pn533_i2c_irq_thread_fn(int irq, void *data)
 145 {
 146         struct pn533_i2c_phy *phy = data;
 147         struct i2c_client *client;
 148         struct sk_buff *skb = NULL;
 149         int r;
 150
 151         if (!phy || irq != phy->i2c_dev->irq) {
 152                 WARN_ON_ONCE(1);
 153                 return IRQ_NONE;
 154         }
 155
 156         client = phy->i2c_dev;
 157         dev_dbg(&client->dev, "IRQ\n");
 158
 159         if (phy->hard_fault != 0)
 160                 return IRQ_HANDLED;
 161
 162         r = pn533_i2c_read(phy, &skb);
 163         if (r == -EREMOTEIO) {
 164                 phy->hard_fault = r;
 165
 166                 pn533_recv_frame(phy->priv, NULL, -EREMOTEIO);
 167
 168                 return IRQ_HANDLED;
 169         } else if ((r == -ENOMEM) || (r == -EBADMSG) || (r == -EBUSY)) {
 170                 return IRQ_HANDLED;
 171         }
 172
 173         if (!phy->aborted)
 174                 pn533_recv_frame(phy->priv, skb, 0);
 175
 176         return IRQ_HANDLED;
 177 }
 178
 179 static struct pn533_phy_ops i2c_phy_ops = {
 180         .send_frame = pn533_i2c_send_frame,
 181         .send_ack = pn533_i2c_send_ack,
 182         .abort_cmd = pn533_i2c_abort_cmd,
 183 };
 184
 185
 186 static int pn533_i2c_probe(struct i2c_client *client,
 187                                const struct i2c_device_id *id)
 188 {
 189         struct pn533_i2c_phy *phy;
 190         struct pn533 *priv;
 191         int r = 0;
 192
 193         dev_dbg(&client->dev, "%s\n", __func__);
 194         dev_dbg(&client->dev, "IRQ: %d\n", client->irq);
 195
 196         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 197                 nfc_err(&client->dev, "Need I2C_FUNC_I2C\n");
 198                 return -ENODEV;
 199         }
 200
 201         phy = devm_kzalloc(&client->dev, sizeof(struct pn533_i2c_phy),
 202                            GFP_KERNEL);
 203         if (!phy)
 204                 return -ENOMEM;
 205
 206         phy->i2c_dev = client;
 207         i2c_set_clientdata(client, phy);
 208
 209         r = request_threaded_irq(client->irq, NULL, pn533_i2c_irq_thread_fn,
 210                                  IRQF_TRIGGER_FALLING |
 211                                  IRQF_SHARED | IRQF_ONESHOT,
 212                                  PN533_I2C_DRIVER_NAME, phy);
 213
 214         if (r < 0)
 215                 nfc_err(&client->dev, "Unable to register IRQ handler\n");
 216
 217         priv = pn533_register_device(PN533_DEVICE_PN532,
 218                                      PN533_NO_TYPE_B_PROTOCOLS,
 219                                      PN533_PROTO_REQ_ACK_RESP,
 220                                      phy, &i2c_phy_ops, NULL,
 221                                      &phy->i2c_dev->dev,
 222                                      &client->dev);
 223
 224         if (IS_ERR(priv)) {
 225                 r = PTR_ERR(priv);
 226                 goto err_register;
 227         }
 228
 229         phy->priv = priv;
 230
 231         return 0;
 232
 233 err_register:
 234         free_irq(client->irq, phy);
 235
 236         return r;
 237 }
 238
 239 static int pn533_i2c_remove(struct i2c_client *client)
 240 {
 241         struct pn533_i2c_phy *phy = i2c_get_clientdata(client);
 242
 243         dev_dbg(&client->dev, "%s\n", __func__);
 244
 245         pn533_unregister_device(phy->priv);
 246
 247         free_irq(client->irq, phy);
 248
 249         return 0;
 250 }
 251
 252 static const struct of_device_id of_pn533_i2c_match[] = {
 253         { .compatible = "nxp,pn533-i2c", },
 254         { .compatible = "nxp,pn532-i2c", },
 255         {},
 256 };
 257 MODULE_DEVICE_TABLE(of, of_pn533_i2c_match);
 258
 259 static struct i2c_device_id pn533_i2c_id_table[] = {
 260         { PN533_I2C_DRIVER_NAME, 0 },
 261         {}
 262 };
 263 MODULE_DEVICE_TABLE(i2c, pn533_i2c_id_table);
 264
 265 static struct i2c_driver pn533_i2c_driver = {
 266         .driver = {
 267                    .name = PN533_I2C_DRIVER_NAME,
 268                    .owner = THIS_MODULE,
 269                    .of_match_table = of_match_ptr(of_pn533_i2c_match),
 270                   },
 271         .probe = pn533_i2c_probe,
 272         .id_table = pn533_i2c_id_table,
 273         .remove = pn533_i2c_remove,
 274 };
 275
 276 module_i2c_driver(pn533_i2c_driver);
 277
 278 MODULE_AUTHOR("Michael Thalmeier <michael.thalmeier@hale.at>");
 279 MODULE_DESCRIPTION("PN533 I2C driver ver " VERSION);
 280 MODULE_VERSION(VERSION);
 281 MODULE_LICENSE("GPL");