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 i2c_client *client; 161 struct sk_buff *skb = NULL; 162 int r; 163 164 if (!phy || !phy->ndlc || irq != phy->i2c_dev->irq) { 165 WARN_ON_ONCE(1); 166 return IRQ_NONE; 167 } 168 169 client = phy->i2c_dev; 170 dev_dbg(&client->dev, "IRQ\n"); 171 172 if (phy->ndlc->hard_fault) 173 return IRQ_HANDLED; 174 175 if (!phy->ndlc->powered) { 176 st_nci_i2c_disable(phy); 177 return IRQ_HANDLED; 178 } 179 180 r = st_nci_i2c_read(phy, &skb); 181 if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG) 182 return IRQ_HANDLED; 183 184 ndlc_recv(phy->ndlc, skb); 185 186 return IRQ_HANDLED; 187 } 188 189 static struct nfc_phy_ops i2c_phy_ops = { 190 .write = st_nci_i2c_write, 191 .enable = st_nci_i2c_enable, 192 .disable = st_nci_i2c_disable, 193 }; 194 195 static const struct acpi_gpio_params reset_gpios = { 1, 0, false }; 196 197 static const struct acpi_gpio_mapping acpi_st_nci_gpios[] = { 198 { "reset-gpios", &reset_gpios, 1 }, 199 {}, 200 }; 201 202 static int st_nci_i2c_probe(struct i2c_client *client, 203 const struct i2c_device_id *id) 204 { 205 struct device *dev = &client->dev; 206 struct st_nci_i2c_phy *phy; 207 int r; 208 209 dev_dbg(&client->dev, "%s\n", __func__); 210 dev_dbg(&client->dev, "IRQ: %d\n", client->irq); 211 212 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { 213 nfc_err(&client->dev, "Need I2C_FUNC_I2C\n"); 214 return -ENODEV; 215 } 216 217 phy = devm_kzalloc(dev, sizeof(struct st_nci_i2c_phy), GFP_KERNEL); 218 if (!phy) 219 return -ENOMEM; 220 221 phy->i2c_dev = client; 222 223 i2c_set_clientdata(client, phy); 224 225 r = devm_acpi_dev_add_driver_gpios(dev, acpi_st_nci_gpios); 226 if (r) 227 dev_dbg(dev, "Unable to add GPIO mapping table\n"); 228 229 /* Get RESET GPIO */ 230 phy->gpiod_reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH); 231 if (IS_ERR(phy->gpiod_reset)) { 232 nfc_err(dev, "Unable to get RESET GPIO\n"); 233 return -ENODEV; 234 } 235 236 phy->se_status.is_ese_present = 237 device_property_read_bool(dev, "ese-present"); 238 phy->se_status.is_uicc_present = 239 device_property_read_bool(dev, "uicc-present"); 240 241 r = ndlc_probe(phy, &i2c_phy_ops, &client->dev, 242 ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM, 243 &phy->ndlc, &phy->se_status); 244 if (r < 0) { 245 nfc_err(&client->dev, "Unable to register ndlc layer\n"); 246 return r; 247 } 248 249 phy->irq_active = true; 250 r = devm_request_threaded_irq(&client->dev, client->irq, NULL, 251 st_nci_irq_thread_fn, 252 IRQF_ONESHOT, 253 ST_NCI_DRIVER_NAME, phy); 254 if (r < 0) 255 nfc_err(&client->dev, "Unable to register IRQ handler\n"); 256 257 return r; 258 } 259 260 static int st_nci_i2c_remove(struct i2c_client *client) 261 { 262 struct st_nci_i2c_phy *phy = i2c_get_clientdata(client); 263 264 dev_dbg(&client->dev, "%s\n", __func__); 265 266 ndlc_remove(phy->ndlc); 267 268 return 0; 269 } 270 271 static const struct i2c_device_id st_nci_i2c_id_table[] = { 272 {ST_NCI_DRIVER_NAME, 0}, 273 {} 274 }; 275 MODULE_DEVICE_TABLE(i2c, st_nci_i2c_id_table); 276 277 static const struct acpi_device_id st_nci_i2c_acpi_match[] = { 278 {"SMO2101"}, 279 {"SMO2102"}, 280 {} 281 }; 282 MODULE_DEVICE_TABLE(acpi, st_nci_i2c_acpi_match); 283 284 static const struct of_device_id of_st_nci_i2c_match[] = { 285 { .compatible = "st,st21nfcb-i2c", }, 286 { .compatible = "st,st21nfcb_i2c", }, 287 { .compatible = "st,st21nfcc-i2c", }, 288 {} 289 }; 290 MODULE_DEVICE_TABLE(of, of_st_nci_i2c_match); 291 292 static struct i2c_driver st_nci_i2c_driver = { 293 .driver = { 294 .name = ST_NCI_I2C_DRIVER_NAME, 295 .of_match_table = of_match_ptr(of_st_nci_i2c_match), 296 .acpi_match_table = ACPI_PTR(st_nci_i2c_acpi_match), 297 }, 298 .probe = st_nci_i2c_probe, 299 .id_table = st_nci_i2c_id_table, 300 .remove = st_nci_i2c_remove, 301 }; 302 module_i2c_driver(st_nci_i2c_driver); 303 304 MODULE_LICENSE("GPL"); 305 MODULE_DESCRIPTION(DRIVER_DESC); 306