drivers/nfc/st-nci/i2c.c

   1 /*
   2  * I2C Link Layer for ST NCI NFC controller familly based Driver
   3  * Copyright (C) 2014-2015 STMicroelectronics SAS. All rights reserved.
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms and conditions of the GNU General Public License,
   7  * version 2, as published by the Free Software Foundation.
   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  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  19
  20 #include <linux/module.h>
  21 #include <linux/i2c.h>
  22 #include <linux/gpio/consumer.h>
  23 #include <linux/acpi.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/delay.h>
  26 #include <linux/nfc.h>
  27 #include <linux/of.h>
  28
  29 #include "st-nci.h"
  30
  31 #define DRIVER_DESC "NCI NFC driver for ST_NCI"
  32
  33 /* ndlc header */
  34 #define ST_NCI_FRAME_HEADROOM 1
  35 #define ST_NCI_FRAME_TAILROOM 0
  36
  37 #define ST_NCI_I2C_MIN_SIZE 4   /* PCB(1) + NCI Packet header(3) */
  38 #define ST_NCI_I2C_MAX_SIZE 250 /* req 4.2.1 */
  39
  40 #define ST_NCI_DRIVER_NAME "st_nci"
  41 #define ST_NCI_I2C_DRIVER_NAME "st_nci_i2c"
  42
  43 struct st_nci_i2c_phy {
  44         struct i2c_client *i2c_dev;
  45         struct llt_ndlc *ndlc;
  46
  47         bool irq_active;
  48
  49         struct gpio_desc *gpiod_reset;
  50
  51         struct st_nci_se_status se_status;
  52 };
  53
  54 static int st_nci_i2c_enable(void *phy_id)
  55 {
  56         struct st_nci_i2c_phy *phy = phy_id;
  57
  58         gpiod_set_value(phy->gpiod_reset, 0);
  59         usleep_range(10000, 15000);
  60         gpiod_set_value(phy->gpiod_reset, 1);
  61         usleep_range(80000, 85000);
  62
  63         if (phy->ndlc->powered == 0 && phy->irq_active == 0) {
  64                 enable_irq(phy->i2c_dev->irq);
  65                 phy->irq_active = true;
  66         }
  67
  68         return 0;
  69 }
  70
  71 static void st_nci_i2c_disable(void *phy_id)
  72 {
  73         struct st_nci_i2c_phy *phy = phy_id;
  74
  75         disable_irq_nosync(phy->i2c_dev->irq);
  76         phy->irq_active = false;
  77 }
  78
  79 /*
  80  * Writing a frame must not return the number of written bytes.
  81  * It must return either zero for success, or <0 for error.
  82  * In addition, it must not alter the skb
  83  */
  84 static int st_nci_i2c_write(void *phy_id, struct sk_buff *skb)
  85 {
  86         int r = -1;
  87         struct st_nci_i2c_phy *phy = phy_id;
  88         struct i2c_client *client = phy->i2c_dev;
  89
  90         if (phy->ndlc->hard_fault != 0)
  91                 return phy->ndlc->hard_fault;
  92
  93         r = i2c_master_send(client, skb->data, skb->len);
  94         if (r < 0) {  /* Retry, chip was in standby */
  95                 usleep_range(1000, 4000);
  96                 r = i2c_master_send(client, skb->data, skb->len);
  97         }
  98
  99         if (r >= 0) {
 100                 if (r != skb->len)
 101                         r = -EREMOTEIO;
 102                 else
 103                         r = 0;
 104         }
 105
 106         return r;
 107 }
 108
 109 /*
 110  * Reads an ndlc frame and returns it in a newly allocated sk_buff.
 111  * returns:
 112  * 0 : if received frame is complete
 113  * -EREMOTEIO : i2c read error (fatal)
 114  * -EBADMSG : frame was incorrect and discarded
 115  * -ENOMEM : cannot allocate skb, frame dropped
 116  */
 117 static int st_nci_i2c_read(struct st_nci_i2c_phy *phy,
 118                                  struct sk_buff **skb)
 119 {
 120         int r;
 121         u8 len;
 122         u8 buf[ST_NCI_I2C_MAX_SIZE];
 123         struct i2c_client *client = phy->i2c_dev;
 124
 125         r = i2c_master_recv(client, buf, ST_NCI_I2C_MIN_SIZE);
 126         if (r < 0) {  /* Retry, chip was in standby */
 127                 usleep_range(1000, 4000);
 128                 r = i2c_master_recv(client, buf, ST_NCI_I2C_MIN_SIZE);
 129         }
 130
 131         if (r != ST_NCI_I2C_MIN_SIZE)
 132                 return -EREMOTEIO;
 133
 134         len = be16_to_cpu(*(__be16 *) (buf + 2));
 135         if (len > ST_NCI_I2C_MAX_SIZE) {
 136                 nfc_err(&client->dev, "invalid frame len\n");
 137                 return -EBADMSG;
 138         }
 139
 140         *skb = alloc_skb(ST_NCI_I2C_MIN_SIZE + len, GFP_KERNEL);
 141         if (*skb == NULL)
 142                 return -ENOMEM;
 143
 144         skb_reserve(*skb, ST_NCI_I2C_MIN_SIZE);
 145         skb_put(*skb, ST_NCI_I2C_MIN_SIZE);
 146         memcpy((*skb)->data, buf, ST_NCI_I2C_MIN_SIZE);
 147
 148         if (!len)
 149                 return 0;
 150
 151         r = i2c_master_recv(client, buf, len);
 152         if (r != len) {
 153                 kfree_skb(*skb);
 154                 return -EREMOTEIO;
 155         }
 156
 157         skb_put(*skb, len);
 158         memcpy((*skb)->data + ST_NCI_I2C_MIN_SIZE, buf, len);
 159
 160         return 0;
 161 }
 162
 163 /*
 164  * Reads an ndlc frame from the chip.
 165  *
 166  * On ST_NCI, IRQ goes in idle state when read starts.
 167  */
 168 static irqreturn_t st_nci_irq_thread_fn(int irq, void *phy_id)
 169 {
 170         struct st_nci_i2c_phy *phy = phy_id;
 171         struct i2c_client *client;
 172         struct sk_buff *skb = NULL;
 173         int r;
 174
 175         if (!phy || !phy->ndlc || irq != phy->i2c_dev->irq) {
 176                 WARN_ON_ONCE(1);
 177                 return IRQ_NONE;
 178         }
 179
 180         client = phy->i2c_dev;
 181         dev_dbg(&client->dev, "IRQ\n");
 182
 183         if (phy->ndlc->hard_fault)
 184                 return IRQ_HANDLED;
 185
 186         if (!phy->ndlc->powered) {
 187                 st_nci_i2c_disable(phy);
 188                 return IRQ_HANDLED;
 189         }
 190
 191         r = st_nci_i2c_read(phy, &skb);
 192         if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG)
 193                 return IRQ_HANDLED;
 194
 195         ndlc_recv(phy->ndlc, skb);
 196
 197         return IRQ_HANDLED;
 198 }
 199
 200 static struct nfc_phy_ops i2c_phy_ops = {
 201         .write = st_nci_i2c_write,
 202         .enable = st_nci_i2c_enable,
 203         .disable = st_nci_i2c_disable,
 204 };
 205
 206 static const struct acpi_gpio_params reset_gpios = { 1, 0, false };
 207
 208 static const struct acpi_gpio_mapping acpi_st_nci_gpios[] = {
 209         { "reset-gpios", &reset_gpios, 1 },
 210         {},
 211 };
 212
 213 static int st_nci_i2c_probe(struct i2c_client *client,
 214                                   const struct i2c_device_id *id)
 215 {
 216         struct device *dev = &client->dev;
 217         struct st_nci_i2c_phy *phy;
 218         int r;
 219
 220         dev_dbg(&client->dev, "%s\n", __func__);
 221         dev_dbg(&client->dev, "IRQ: %d\n", client->irq);
 222
 223         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 224                 nfc_err(&client->dev, "Need I2C_FUNC_I2C\n");
 225                 return -ENODEV;
 226         }
 227
 228         phy = devm_kzalloc(dev, sizeof(struct st_nci_i2c_phy), GFP_KERNEL);
 229         if (!phy)
 230                 return -ENOMEM;
 231
 232         phy->i2c_dev = client;
 233
 234         i2c_set_clientdata(client, phy);
 235
 236         r = devm_acpi_dev_add_driver_gpios(dev, acpi_st_nci_gpios);
 237         if (r)
 238                 dev_dbg(dev, "Unable to add GPIO mapping table\n");
 239
 240         /* Get RESET GPIO */
 241         phy->gpiod_reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
 242         if (IS_ERR(phy->gpiod_reset)) {
 243                 nfc_err(dev, "Unable to get RESET GPIO\n");
 244                 return -ENODEV;
 245         }
 246
 247         phy->se_status.is_ese_present =
 248                                 device_property_read_bool(dev, "ese-present");
 249         phy->se_status.is_uicc_present =
 250                                 device_property_read_bool(dev, "uicc-present");
 251
 252         r = ndlc_probe(phy, &i2c_phy_ops, &client->dev,
 253                         ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM,
 254                         &phy->ndlc, &phy->se_status);
 255         if (r < 0) {
 256                 nfc_err(&client->dev, "Unable to register ndlc layer\n");
 257                 return r;
 258         }
 259
 260         phy->irq_active = true;
 261         r = devm_request_threaded_irq(&client->dev, client->irq, NULL,
 262                                 st_nci_irq_thread_fn,
 263                                 IRQF_ONESHOT,
 264                                 ST_NCI_DRIVER_NAME, phy);
 265         if (r < 0)
 266                 nfc_err(&client->dev, "Unable to register IRQ handler\n");
 267
 268         return r;
 269 }
 270
 271 static int st_nci_i2c_remove(struct i2c_client *client)
 272 {
 273         struct st_nci_i2c_phy *phy = i2c_get_clientdata(client);
 274
 275         dev_dbg(&client->dev, "%s\n", __func__);
 276
 277         ndlc_remove(phy->ndlc);
 278
 279         return 0;
 280 }
 281
 282 static const struct i2c_device_id st_nci_i2c_id_table[] = {
 283         {ST_NCI_DRIVER_NAME, 0},
 284         {}
 285 };
 286 MODULE_DEVICE_TABLE(i2c, st_nci_i2c_id_table);
 287
 288 static const struct acpi_device_id st_nci_i2c_acpi_match[] = {
 289         {"SMO2101"},
 290         {"SMO2102"},
 291         {}
 292 };
 293 MODULE_DEVICE_TABLE(acpi, st_nci_i2c_acpi_match);
 294
 295 static const struct of_device_id of_st_nci_i2c_match[] = {
 296         { .compatible = "st,st21nfcb-i2c", },
 297         { .compatible = "st,st21nfcb_i2c", },
 298         { .compatible = "st,st21nfcc-i2c", },
 299         {}
 300 };
 301 MODULE_DEVICE_TABLE(of, of_st_nci_i2c_match);
 302
 303 static struct i2c_driver st_nci_i2c_driver = {
 304         .driver = {
 305                 .name = ST_NCI_I2C_DRIVER_NAME,
 306                 .of_match_table = of_match_ptr(of_st_nci_i2c_match),
 307                 .acpi_match_table = ACPI_PTR(st_nci_i2c_acpi_match),
 308         },
 309         .probe = st_nci_i2c_probe,
 310         .id_table = st_nci_i2c_id_table,
 311         .remove = st_nci_i2c_remove,
 312 };
 313 module_i2c_driver(st_nci_i2c_driver);
 314
 315 MODULE_LICENSE("GPL");
 316 MODULE_DESCRIPTION(DRIVER_DESC);