drivers/nfc/st-nci/i2c.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * I2C Link Layer for ST NCI NFC controller familly 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/i2c.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
  18 #include "st-nci.h"
  19
  20 #define DRIVER_DESC "NCI NFC driver for ST_NCI"
  21
  22 /* ndlc header */
  23 #define ST_NCI_FRAME_HEADROOM 1
  24 #define ST_NCI_FRAME_TAILROOM 0
  25
  26 #define ST_NCI_I2C_MIN_SIZE 4   /* PCB(1) + NCI Packet header(3) */
  27 #define ST_NCI_I2C_MAX_SIZE 250 /* req 4.2.1 */
  28
  29 #define ST_NCI_DRIVER_NAME "st_nci"
  30 #define ST_NCI_I2C_DRIVER_NAME "st_nci_i2c"
  31
  32 struct st_nci_i2c_phy {
  33         struct i2c_client *i2c_dev;
  34         struct llt_ndlc *ndlc;
  35
  36         bool irq_active;
  37
  38         struct gpio_desc *gpiod_reset;
  39
  40         struct st_nci_se_status se_status;
  41 };
  42
  43 static int st_nci_i2c_enable(void *phy_id)
  44 {
  45         struct st_nci_i2c_phy *phy = phy_id;
  46
  47         gpiod_set_value(phy->gpiod_reset, 0);
  48         usleep_range(10000, 15000);
  49         gpiod_set_value(phy->gpiod_reset, 1);
  50         usleep_range(80000, 85000);
  51
  52         if (phy->ndlc->powered == 0 && phy->irq_active == 0) {
  53                 enable_irq(phy->i2c_dev->irq);
  54                 phy->irq_active = true;
  55         }
  56
  57         return 0;
  58 }
  59
  60 static void st_nci_i2c_disable(void *phy_id)
  61 {
  62         struct st_nci_i2c_phy *phy = phy_id;
  63
  64         disable_irq_nosync(phy->i2c_dev->irq);
  65         phy->irq_active = false;
  66 }
  67
  68 /*
  69  * Writing a frame must not return the number of written bytes.
  70  * It must return either zero for success, or <0 for error.
  71  * In addition, it must not alter the skb
  72  */
  73 static int st_nci_i2c_write(void *phy_id, struct sk_buff *skb)
  74 {
  75         int r;
  76         struct st_nci_i2c_phy *phy = phy_id;
  77         struct i2c_client *client = phy->i2c_dev;
  78
  79         if (phy->ndlc->hard_fault != 0)
  80                 return phy->ndlc->hard_fault;
  81
  82         r = i2c_master_send(client, skb->data, skb->len);
  83         if (r < 0) {  /* Retry, chip was in standby */
  84                 usleep_range(1000, 4000);
  85                 r = i2c_master_send(client, skb->data, skb->len);
  86         }
  87
  88         if (r >= 0) {
  89                 if (r != skb->len)
  90                         r = -EREMOTEIO;
  91                 else
  92                         r = 0;
  93         }
  94
  95         return r;
  96 }
  97
  98 /*
  99  * Reads an ndlc frame and returns it in a newly allocated sk_buff.
 100  * returns:
 101  * 0 : if received frame is complete
 102  * -EREMOTEIO : i2c read error (fatal)
 103  * -EBADMSG : frame was incorrect and discarded
 104  * -ENOMEM : cannot allocate skb, frame dropped
 105  */
 106 static int st_nci_i2c_read(struct st_nci_i2c_phy *phy,
 107                                  struct sk_buff **skb)
 108 {
 109         int r;
 110         u8 len;
 111         u8 buf[ST_NCI_I2C_MAX_SIZE];
 112         struct i2c_client *client = phy->i2c_dev;
 113
 114         r = i2c_master_recv(client, buf, ST_NCI_I2C_MIN_SIZE);
 115         if (r < 0) {  /* Retry, chip was in standby */
 116                 usleep_range(1000, 4000);
 117                 r = i2c_master_recv(client, buf, ST_NCI_I2C_MIN_SIZE);
 118         }
 119
 120         if (r != ST_NCI_I2C_MIN_SIZE)
 121                 return -EREMOTEIO;
 122
 123         len = be16_to_cpu(*(__be16 *) (buf + 2));
 124         if (len > ST_NCI_I2C_MAX_SIZE) {
 125                 nfc_err(&client->dev, "invalid frame len\n");
 126                 return -EBADMSG;
 127         }
 128
 129         *skb = alloc_skb(ST_NCI_I2C_MIN_SIZE + len, GFP_KERNEL);
 130         if (*skb == NULL)
 131                 return -ENOMEM;
 132
 133         skb_reserve(*skb, ST_NCI_I2C_MIN_SIZE);
 134         skb_put(*skb, ST_NCI_I2C_MIN_SIZE);
 135         memcpy((*skb)->data, buf, ST_NCI_I2C_MIN_SIZE);
 136
 137         if (!len)
 138                 return 0;
 139
 140         r = i2c_master_recv(client, buf, len);
 141         if (r != len) {
 142                 kfree_skb(*skb);
 143                 return -EREMOTEIO;
 144         }
 145
 146         skb_put(*skb, len);
 147         memcpy((*skb)->data + ST_NCI_I2C_MIN_SIZE, buf, len);
 148
 149         return 0;
 150 }
 151
 152 /*
 153  * Reads an ndlc frame from the chip.
 154  *
 155  * On ST_NCI, IRQ goes in idle state when read starts.
 156  */
 157 static irqreturn_t st_nci_irq_thread_fn(int irq, void *phy_id)
 158 {
 159         struct st_nci_i2c_phy *phy = phy_id;
 160         struct sk_buff *skb = NULL;
 161         int r;
 162
 163         if (!phy || !phy->ndlc || irq != phy->i2c_dev->irq) {
 164                 WARN_ON_ONCE(1);
 165                 return IRQ_NONE;
 166         }
 167
 168         if (phy->ndlc->hard_fault)
 169                 return IRQ_HANDLED;
 170
 171         if (!phy->ndlc->powered) {
 172                 st_nci_i2c_disable(phy);
 173                 return IRQ_HANDLED;
 174         }
 175
 176         r = st_nci_i2c_read(phy, &skb);
 177         if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG)
 178                 return IRQ_HANDLED;
 179
 180         ndlc_recv(phy->ndlc, skb);
 181
 182         return IRQ_HANDLED;
 183 }
 184
 185 static const struct nfc_phy_ops i2c_phy_ops = {
 186         .write = st_nci_i2c_write,
 187         .enable = st_nci_i2c_enable,
 188         .disable = st_nci_i2c_disable,
 189 };
 190
 191 static const struct acpi_gpio_params reset_gpios = { 1, 0, false };
 192
 193 static const struct acpi_gpio_mapping acpi_st_nci_gpios[] = {
 194         { "reset-gpios", &reset_gpios, 1 },
 195         {},
 196 };
 197
 198 static int st_nci_i2c_probe(struct i2c_client *client)
 199 {
 200         struct device *dev = &client->dev;
 201         struct st_nci_i2c_phy *phy;
 202         int r;
 203
 204         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 205                 nfc_err(&client->dev, "Need I2C_FUNC_I2C\n");
 206                 return -ENODEV;
 207         }
 208
 209         phy = devm_kzalloc(dev, sizeof(struct st_nci_i2c_phy), GFP_KERNEL);
 210         if (!phy)
 211                 return -ENOMEM;
 212
 213         phy->i2c_dev = client;
 214
 215         i2c_set_clientdata(client, phy);
 216
 217         r = devm_acpi_dev_add_driver_gpios(dev, acpi_st_nci_gpios);
 218         if (r)
 219                 dev_dbg(dev, "Unable to add GPIO mapping table\n");
 220
 221         /* Get RESET GPIO */
 222         phy->gpiod_reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
 223         if (IS_ERR(phy->gpiod_reset)) {
 224                 nfc_err(dev, "Unable to get RESET GPIO\n");
 225                 return -ENODEV;
 226         }
 227
 228         phy->se_status.is_ese_present =
 229                                 device_property_read_bool(dev, "ese-present");
 230         phy->se_status.is_uicc_present =
 231                                 device_property_read_bool(dev, "uicc-present");
 232
 233         r = ndlc_probe(phy, &i2c_phy_ops, &client->dev,
 234                         ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM,
 235                         &phy->ndlc, &phy->se_status);
 236         if (r < 0) {
 237                 nfc_err(&client->dev, "Unable to register ndlc layer\n");
 238                 return r;
 239         }
 240
 241         phy->irq_active = true;
 242         r = devm_request_threaded_irq(&client->dev, client->irq, NULL,
 243                                 st_nci_irq_thread_fn,
 244                                 IRQF_ONESHOT,
 245                                 ST_NCI_DRIVER_NAME, phy);
 246         if (r < 0)
 247                 nfc_err(&client->dev, "Unable to register IRQ handler\n");
 248
 249         return r;
 250 }
 251
 252 static void st_nci_i2c_remove(struct i2c_client *client)
 253 {
 254         struct st_nci_i2c_phy *phy = i2c_get_clientdata(client);
 255
 256         ndlc_remove(phy->ndlc);
 257 }
 258
 259 static const struct i2c_device_id st_nci_i2c_id_table[] = {
 260         { ST_NCI_DRIVER_NAME },
 261         {}
 262 };
 263 MODULE_DEVICE_TABLE(i2c, st_nci_i2c_id_table);
 264
 265 static const struct acpi_device_id st_nci_i2c_acpi_match[] __maybe_unused = {
 266         {"SMO2101"},
 267         {"SMO2102"},
 268         {}
 269 };
 270 MODULE_DEVICE_TABLE(acpi, st_nci_i2c_acpi_match);
 271
 272 static const struct of_device_id of_st_nci_i2c_match[] __maybe_unused = {
 273         { .compatible = "st,st21nfcb-i2c", },
 274         { .compatible = "st,st21nfcb_i2c", },
 275         { .compatible = "st,st21nfcc-i2c", },
 276         {}
 277 };
 278 MODULE_DEVICE_TABLE(of, of_st_nci_i2c_match);
 279
 280 static struct i2c_driver st_nci_i2c_driver = {
 281         .driver = {
 282                 .name = ST_NCI_I2C_DRIVER_NAME,
 283                 .of_match_table = of_match_ptr(of_st_nci_i2c_match),
 284                 .acpi_match_table = ACPI_PTR(st_nci_i2c_acpi_match),
 285         },
 286         .probe = st_nci_i2c_probe,
 287         .id_table = st_nci_i2c_id_table,
 288         .remove = st_nci_i2c_remove,
 289 };
 290 module_i2c_driver(st_nci_i2c_driver);
 291
 292 MODULE_LICENSE("GPL");
 293 MODULE_DESCRIPTION(DRIVER_DESC);