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 return -ENOMEM; 100 101 skb_put(skb_rx, skb->len); 102 memcpy(skb_rx->data, buf, skb->len); 103 ndlc_recv(phy->ndlc, skb_rx); 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_spi_read(struct st_nci_spi_phy *phy, 118 struct sk_buff **skb) 119 { 120 int r; 121 u8 len; 122 u8 buf[ST_NCI_SPI_MAX_SIZE]; 123 struct spi_device *dev = phy->spi_dev; 124 struct spi_transfer spi_xfer = { 125 .rx_buf = buf, 126 .len = ST_NCI_SPI_MIN_SIZE, 127 }; 128 129 r = spi_sync_transfer(dev, &spi_xfer, 1); 130 if (r < 0) 131 return -EREMOTEIO; 132 133 len = be16_to_cpu(*(__be16 *) (buf + 2)); 134 if (len > ST_NCI_SPI_MAX_SIZE) { 135 nfc_err(&dev->dev, "invalid frame len\n"); 136 phy->ndlc->hard_fault = 1; 137 return -EBADMSG; 138 } 139 140 *skb = alloc_skb(ST_NCI_SPI_MIN_SIZE + len, GFP_KERNEL); 141 if (*skb == NULL) 142 return -ENOMEM; 143 144 skb_reserve(*skb, ST_NCI_SPI_MIN_SIZE); 145 skb_put(*skb, ST_NCI_SPI_MIN_SIZE); 146 memcpy((*skb)->data, buf, ST_NCI_SPI_MIN_SIZE); 147 148 if (!len) 149 return 0; 150 151 spi_xfer.len = len; 152 r = spi_sync_transfer(dev, &spi_xfer, 1); 153 if (r < 0) { 154 kfree_skb(*skb); 155 return -EREMOTEIO; 156 } 157 158 skb_put(*skb, len); 159 memcpy((*skb)->data + ST_NCI_SPI_MIN_SIZE, buf, len); 160 161 return 0; 162 } 163 164 /* 165 * Reads an ndlc frame from the chip. 166 * 167 * On ST21NFCB, IRQ goes in idle state when read starts. 168 */ 169 static irqreturn_t st_nci_irq_thread_fn(int irq, void *phy_id) 170 { 171 struct st_nci_spi_phy *phy = phy_id; 172 struct spi_device *dev; 173 struct sk_buff *skb = NULL; 174 int r; 175 176 if (!phy || !phy->ndlc || irq != phy->spi_dev->irq) { 177 WARN_ON_ONCE(1); 178 return IRQ_NONE; 179 } 180 181 dev = phy->spi_dev; 182 dev_dbg(&dev->dev, "IRQ\n"); 183 184 if (phy->ndlc->hard_fault) 185 return IRQ_HANDLED; 186 187 if (!phy->ndlc->powered) { 188 st_nci_spi_disable(phy); 189 return IRQ_HANDLED; 190 } 191 192 r = st_nci_spi_read(phy, &skb); 193 if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG) 194 return IRQ_HANDLED; 195 196 ndlc_recv(phy->ndlc, skb); 197 198 return IRQ_HANDLED; 199 } 200 201 static struct nfc_phy_ops spi_phy_ops = { 202 .write = st_nci_spi_write, 203 .enable = st_nci_spi_enable, 204 .disable = st_nci_spi_disable, 205 }; 206 207 static const struct acpi_gpio_params reset_gpios = { 1, 0, false }; 208 209 static const struct acpi_gpio_mapping acpi_st_nci_gpios[] = { 210 { "reset-gpios", &reset_gpios, 1 }, 211 {}, 212 }; 213 214 static int st_nci_spi_probe(struct spi_device *dev) 215 { 216 struct st_nci_spi_phy *phy; 217 int r; 218 219 /* Check SPI platform functionnalities */ 220 if (!dev) { 221 pr_debug("%s: dev is NULL. Device is not accessible.\n", 222 __func__); 223 return -ENODEV; 224 } 225 226 phy = devm_kzalloc(&dev->dev, sizeof(struct st_nci_spi_phy), 227 GFP_KERNEL); 228 if (!phy) 229 return -ENOMEM; 230 231 phy->spi_dev = dev; 232 233 spi_set_drvdata(dev, phy); 234 235 r = devm_acpi_dev_add_driver_gpios(&dev->dev, acpi_st_nci_gpios); 236 if (r) 237 dev_dbg(&dev->dev, "Unable to add GPIO mapping table\n"); 238 239 /* Get RESET GPIO */ 240 phy->gpiod_reset = devm_gpiod_get(&dev->dev, "reset", GPIOD_OUT_HIGH); 241 if (IS_ERR(phy->gpiod_reset)) { 242 nfc_err(&dev->dev, "Unable to get RESET GPIO\n"); 243 return PTR_ERR(phy->gpiod_reset); 244 } 245 246 phy->se_status.is_ese_present = 247 device_property_read_bool(&dev->dev, "ese-present"); 248 phy->se_status.is_uicc_present = 249 device_property_read_bool(&dev->dev, "uicc-present"); 250 251 r = ndlc_probe(phy, &spi_phy_ops, &dev->dev, 252 ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM, 253 &phy->ndlc, &phy->se_status); 254 if (r < 0) { 255 nfc_err(&dev->dev, "Unable to register ndlc layer\n"); 256 return r; 257 } 258 259 phy->irq_active = true; 260 r = devm_request_threaded_irq(&dev->dev, dev->irq, NULL, 261 st_nci_irq_thread_fn, 262 IRQF_ONESHOT, 263 ST_NCI_SPI_DRIVER_NAME, phy); 264 if (r < 0) 265 nfc_err(&dev->dev, "Unable to register IRQ handler\n"); 266 267 return r; 268 } 269 270 static int st_nci_spi_remove(struct spi_device *dev) 271 { 272 struct st_nci_spi_phy *phy = spi_get_drvdata(dev); 273 274 ndlc_remove(phy->ndlc); 275 276 return 0; 277 } 278 279 static struct spi_device_id st_nci_spi_id_table[] = { 280 {ST_NCI_SPI_DRIVER_NAME, 0}, 281 {} 282 }; 283 MODULE_DEVICE_TABLE(spi, st_nci_spi_id_table); 284 285 static const struct acpi_device_id st_nci_spi_acpi_match[] __maybe_unused = { 286 {"SMO2101", 0}, 287 {} 288 }; 289 MODULE_DEVICE_TABLE(acpi, st_nci_spi_acpi_match); 290 291 static const struct of_device_id of_st_nci_spi_match[] __maybe_unused = { 292 { .compatible = "st,st21nfcb-spi", }, 293 {} 294 }; 295 MODULE_DEVICE_TABLE(of, of_st_nci_spi_match); 296 297 static struct spi_driver st_nci_spi_driver = { 298 .driver = { 299 .name = ST_NCI_SPI_DRIVER_NAME, 300 .of_match_table = of_match_ptr(of_st_nci_spi_match), 301 .acpi_match_table = ACPI_PTR(st_nci_spi_acpi_match), 302 }, 303 .probe = st_nci_spi_probe, 304 .id_table = st_nci_spi_id_table, 305 .remove = st_nci_spi_remove, 306 }; 307 module_spi_driver(st_nci_spi_driver); 308 309 MODULE_LICENSE("GPL"); 310 MODULE_DESCRIPTION(DRIVER_DESC); 311