1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * SPI Link Layer for ST NCI 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/spi/spi.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 #include <net/nfc/nci.h> 18 19 #include "st-nci.h" 20 21 #define DRIVER_DESC "NCI NFC driver for ST_NCI" 22 23 /* ndlc header */ 24 #define ST_NCI_FRAME_HEADROOM 1 25 #define ST_NCI_FRAME_TAILROOM 0 26 27 #define ST_NCI_SPI_MIN_SIZE 4 /* PCB(1) + NCI Packet header(3) */ 28 #define ST_NCI_SPI_MAX_SIZE 250 /* req 4.2.1 */ 29 30 #define ST_NCI_DRIVER_NAME "st_nci" 31 #define ST_NCI_SPI_DRIVER_NAME "st_nci_spi" 32 33 struct st_nci_spi_phy { 34 struct spi_device *spi_dev; 35 struct llt_ndlc *ndlc; 36 37 bool irq_active; 38 39 struct gpio_desc *gpiod_reset; 40 41 struct st_nci_se_status se_status; 42 }; 43 44 static int st_nci_spi_enable(void *phy_id) 45 { 46 struct st_nci_spi_phy *phy = phy_id; 47 48 gpiod_set_value(phy->gpiod_reset, 0); 49 usleep_range(10000, 15000); 50 gpiod_set_value(phy->gpiod_reset, 1); 51 usleep_range(80000, 85000); 52 53 if (phy->ndlc->powered == 0 && phy->irq_active == 0) { 54 enable_irq(phy->spi_dev->irq); 55 phy->irq_active = true; 56 } 57 58 return 0; 59 } 60 61 static void st_nci_spi_disable(void *phy_id) 62 { 63 struct st_nci_spi_phy *phy = phy_id; 64 65 disable_irq_nosync(phy->spi_dev->irq); 66 phy->irq_active = false; 67 } 68 69 /* 70 * Writing a frame must not return the number of written bytes. 71 * It must return either zero for success, or <0 for error. 72 * In addition, it must not alter the skb 73 */ 74 static int st_nci_spi_write(void *phy_id, struct sk_buff *skb) 75 { 76 int r; 77 struct st_nci_spi_phy *phy = phy_id; 78 struct spi_device *dev = phy->spi_dev; 79 struct sk_buff *skb_rx; 80 u8 buf[ST_NCI_SPI_MAX_SIZE + NCI_DATA_HDR_SIZE + 81 ST_NCI_FRAME_HEADROOM + ST_NCI_FRAME_TAILROOM]; 82 struct spi_transfer spi_xfer = { 83 .tx_buf = skb->data, 84 .rx_buf = buf, 85 .len = skb->len, 86 }; 87 88 if (phy->ndlc->hard_fault != 0) 89 return phy->ndlc->hard_fault; 90 91 r = spi_sync_transfer(dev, &spi_xfer, 1); 92 /* 93 * We may have received some valuable data on miso line. 94 * Send them back in the ndlc state machine. 95 */ 96 if (!r) { 97 skb_rx = alloc_skb(skb->len, GFP_KERNEL); 98 if (!skb_rx) { 99 r = -ENOMEM; 100 goto exit; 101 } 102 103 skb_put(skb_rx, skb->len); 104 memcpy(skb_rx->data, buf, skb->len); 105 ndlc_recv(phy->ndlc, skb_rx); 106 } 107 108 exit: 109 return r; 110 } 111 112 /* 113 * Reads an ndlc frame and returns it in a newly allocated sk_buff. 114 * returns: 115 * 0 : if received frame is complete 116 * -EREMOTEIO : i2c read error (fatal) 117 * -EBADMSG : frame was incorrect and discarded 118 * -ENOMEM : cannot allocate skb, frame dropped 119 */ 120 static int st_nci_spi_read(struct st_nci_spi_phy *phy, 121 struct sk_buff **skb) 122 { 123 int r; 124 u8 len; 125 u8 buf[ST_NCI_SPI_MAX_SIZE]; 126 struct spi_device *dev = phy->spi_dev; 127 struct spi_transfer spi_xfer = { 128 .rx_buf = buf, 129 .len = ST_NCI_SPI_MIN_SIZE, 130 }; 131 132 r = spi_sync_transfer(dev, &spi_xfer, 1); 133 if (r < 0) 134 return -EREMOTEIO; 135 136 len = be16_to_cpu(*(__be16 *) (buf + 2)); 137 if (len > ST_NCI_SPI_MAX_SIZE) { 138 nfc_err(&dev->dev, "invalid frame len\n"); 139 phy->ndlc->hard_fault = 1; 140 return -EBADMSG; 141 } 142 143 *skb = alloc_skb(ST_NCI_SPI_MIN_SIZE + len, GFP_KERNEL); 144 if (*skb == NULL) 145 return -ENOMEM; 146 147 skb_reserve(*skb, ST_NCI_SPI_MIN_SIZE); 148 skb_put(*skb, ST_NCI_SPI_MIN_SIZE); 149 memcpy((*skb)->data, buf, ST_NCI_SPI_MIN_SIZE); 150 151 if (!len) 152 return 0; 153 154 spi_xfer.len = len; 155 r = spi_sync_transfer(dev, &spi_xfer, 1); 156 if (r < 0) { 157 kfree_skb(*skb); 158 return -EREMOTEIO; 159 } 160 161 skb_put(*skb, len); 162 memcpy((*skb)->data + ST_NCI_SPI_MIN_SIZE, buf, len); 163 164 return 0; 165 } 166 167 /* 168 * Reads an ndlc frame from the chip. 169 * 170 * On ST21NFCB, IRQ goes in idle state when read starts. 171 */ 172 static irqreturn_t st_nci_irq_thread_fn(int irq, void *phy_id) 173 { 174 struct st_nci_spi_phy *phy = phy_id; 175 struct spi_device *dev; 176 struct sk_buff *skb = NULL; 177 int r; 178 179 if (!phy || !phy->ndlc || irq != phy->spi_dev->irq) { 180 WARN_ON_ONCE(1); 181 return IRQ_NONE; 182 } 183 184 dev = phy->spi_dev; 185 dev_dbg(&dev->dev, "IRQ\n"); 186 187 if (phy->ndlc->hard_fault) 188 return IRQ_HANDLED; 189 190 if (!phy->ndlc->powered) { 191 st_nci_spi_disable(phy); 192 return IRQ_HANDLED; 193 } 194 195 r = st_nci_spi_read(phy, &skb); 196 if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG) 197 return IRQ_HANDLED; 198 199 ndlc_recv(phy->ndlc, skb); 200 201 return IRQ_HANDLED; 202 } 203 204 static struct nfc_phy_ops spi_phy_ops = { 205 .write = st_nci_spi_write, 206 .enable = st_nci_spi_enable, 207 .disable = st_nci_spi_disable, 208 }; 209 210 static const struct acpi_gpio_params reset_gpios = { 1, 0, false }; 211 212 static const struct acpi_gpio_mapping acpi_st_nci_gpios[] = { 213 { "reset-gpios", &reset_gpios, 1 }, 214 {}, 215 }; 216 217 static int st_nci_spi_probe(struct spi_device *dev) 218 { 219 struct st_nci_spi_phy *phy; 220 int r; 221 222 dev_dbg(&dev->dev, "%s\n", __func__); 223 dev_dbg(&dev->dev, "IRQ: %d\n", dev->irq); 224 225 /* Check SPI platform functionnalities */ 226 if (!dev) { 227 pr_debug("%s: dev is NULL. Device is not accessible.\n", 228 __func__); 229 return -ENODEV; 230 } 231 232 phy = devm_kzalloc(&dev->dev, sizeof(struct st_nci_spi_phy), 233 GFP_KERNEL); 234 if (!phy) 235 return -ENOMEM; 236 237 phy->spi_dev = dev; 238 239 spi_set_drvdata(dev, phy); 240 241 r = devm_acpi_dev_add_driver_gpios(&dev->dev, acpi_st_nci_gpios); 242 if (r) 243 dev_dbg(&dev->dev, "Unable to add GPIO mapping table\n"); 244 245 /* Get RESET GPIO */ 246 phy->gpiod_reset = devm_gpiod_get(&dev->dev, "reset", GPIOD_OUT_HIGH); 247 if (IS_ERR(phy->gpiod_reset)) { 248 nfc_err(&dev->dev, "Unable to get RESET GPIO\n"); 249 return PTR_ERR(phy->gpiod_reset); 250 } 251 252 phy->se_status.is_ese_present = 253 device_property_read_bool(&dev->dev, "ese-present"); 254 phy->se_status.is_uicc_present = 255 device_property_read_bool(&dev->dev, "uicc-present"); 256 257 r = ndlc_probe(phy, &spi_phy_ops, &dev->dev, 258 ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM, 259 &phy->ndlc, &phy->se_status); 260 if (r < 0) { 261 nfc_err(&dev->dev, "Unable to register ndlc layer\n"); 262 return r; 263 } 264 265 phy->irq_active = true; 266 r = devm_request_threaded_irq(&dev->dev, dev->irq, NULL, 267 st_nci_irq_thread_fn, 268 IRQF_ONESHOT, 269 ST_NCI_SPI_DRIVER_NAME, phy); 270 if (r < 0) 271 nfc_err(&dev->dev, "Unable to register IRQ handler\n"); 272 273 return r; 274 } 275 276 static int st_nci_spi_remove(struct spi_device *dev) 277 { 278 struct st_nci_spi_phy *phy = spi_get_drvdata(dev); 279 280 dev_dbg(&dev->dev, "%s\n", __func__); 281 282 ndlc_remove(phy->ndlc); 283 284 return 0; 285 } 286 287 static struct spi_device_id st_nci_spi_id_table[] = { 288 {ST_NCI_SPI_DRIVER_NAME, 0}, 289 {} 290 }; 291 MODULE_DEVICE_TABLE(spi, st_nci_spi_id_table); 292 293 static const struct acpi_device_id st_nci_spi_acpi_match[] = { 294 {"SMO2101", 0}, 295 {} 296 }; 297 MODULE_DEVICE_TABLE(acpi, st_nci_spi_acpi_match); 298 299 static const struct of_device_id of_st_nci_spi_match[] = { 300 { .compatible = "st,st21nfcb-spi", }, 301 {} 302 }; 303 MODULE_DEVICE_TABLE(of, of_st_nci_spi_match); 304 305 static struct spi_driver st_nci_spi_driver = { 306 .driver = { 307 .name = ST_NCI_SPI_DRIVER_NAME, 308 .of_match_table = of_match_ptr(of_st_nci_spi_match), 309 .acpi_match_table = ACPI_PTR(st_nci_spi_acpi_match), 310 }, 311 .probe = st_nci_spi_probe, 312 .id_table = st_nci_spi_id_table, 313 .remove = st_nci_spi_remove, 314 }; 315 module_spi_driver(st_nci_spi_driver); 316 317 MODULE_LICENSE("GPL"); 318 MODULE_DESCRIPTION(DRIVER_DESC); 319