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 const struct i2c_device_id *id) 200 { 201 struct device *dev = &client->dev; 202 struct st_nci_i2c_phy *phy; 203 int r; 204 205 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { 206 nfc_err(&client->dev, "Need I2C_FUNC_I2C\n"); 207 return -ENODEV; 208 } 209 210 phy = devm_kzalloc(dev, sizeof(struct st_nci_i2c_phy), GFP_KERNEL); 211 if (!phy) 212 return -ENOMEM; 213 214 phy->i2c_dev = client; 215 216 i2c_set_clientdata(client, phy); 217 218 r = devm_acpi_dev_add_driver_gpios(dev, acpi_st_nci_gpios); 219 if (r) 220 dev_dbg(dev, "Unable to add GPIO mapping table\n"); 221 222 /* Get RESET GPIO */ 223 phy->gpiod_reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH); 224 if (IS_ERR(phy->gpiod_reset)) { 225 nfc_err(dev, "Unable to get RESET GPIO\n"); 226 return -ENODEV; 227 } 228 229 phy->se_status.is_ese_present = 230 device_property_read_bool(dev, "ese-present"); 231 phy->se_status.is_uicc_present = 232 device_property_read_bool(dev, "uicc-present"); 233 234 r = ndlc_probe(phy, &i2c_phy_ops, &client->dev, 235 ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM, 236 &phy->ndlc, &phy->se_status); 237 if (r < 0) { 238 nfc_err(&client->dev, "Unable to register ndlc layer\n"); 239 return r; 240 } 241 242 phy->irq_active = true; 243 r = devm_request_threaded_irq(&client->dev, client->irq, NULL, 244 st_nci_irq_thread_fn, 245 IRQF_ONESHOT, 246 ST_NCI_DRIVER_NAME, phy); 247 if (r < 0) 248 nfc_err(&client->dev, "Unable to register IRQ handler\n"); 249 250 return r; 251 } 252 253 static int st_nci_i2c_remove(struct i2c_client *client) 254 { 255 struct st_nci_i2c_phy *phy = i2c_get_clientdata(client); 256 257 ndlc_remove(phy->ndlc); 258 259 return 0; 260 } 261 262 static const struct i2c_device_id st_nci_i2c_id_table[] = { 263 {ST_NCI_DRIVER_NAME, 0}, 264 {} 265 }; 266 MODULE_DEVICE_TABLE(i2c, st_nci_i2c_id_table); 267 268 static const struct acpi_device_id st_nci_i2c_acpi_match[] __maybe_unused = { 269 {"SMO2101"}, 270 {"SMO2102"}, 271 {} 272 }; 273 MODULE_DEVICE_TABLE(acpi, st_nci_i2c_acpi_match); 274 275 static const struct of_device_id of_st_nci_i2c_match[] __maybe_unused = { 276 { .compatible = "st,st21nfcb-i2c", }, 277 { .compatible = "st,st21nfcb_i2c", }, 278 { .compatible = "st,st21nfcc-i2c", }, 279 {} 280 }; 281 MODULE_DEVICE_TABLE(of, of_st_nci_i2c_match); 282 283 static struct i2c_driver st_nci_i2c_driver = { 284 .driver = { 285 .name = ST_NCI_I2C_DRIVER_NAME, 286 .of_match_table = of_match_ptr(of_st_nci_i2c_match), 287 .acpi_match_table = ACPI_PTR(st_nci_i2c_acpi_match), 288 }, 289 .probe = st_nci_i2c_probe, 290 .id_table = st_nci_i2c_id_table, 291 .remove = st_nci_i2c_remove, 292 }; 293 module_i2c_driver(st_nci_i2c_driver); 294 295 MODULE_LICENSE("GPL"); 296 MODULE_DESCRIPTION(DRIVER_DESC); 297