diff options
Diffstat (limited to 'drivers/nfc')
| -rw-r--r-- | drivers/nfc/Kconfig | 12 | ||||
| -rw-r--r-- | drivers/nfc/Makefile | 1 | ||||
| -rw-r--r-- | drivers/nfc/trf7970a.c | 1224 |
3 files changed, 1237 insertions, 0 deletions
diff --git a/drivers/nfc/Kconfig b/drivers/nfc/Kconfig index fe20e1cc0545..65d4ca19d132 100644 --- a/drivers/nfc/Kconfig +++ b/drivers/nfc/Kconfig @@ -26,6 +26,18 @@ config NFC_WILINK Say Y here to compile support for Texas Instrument's NFC WiLink driver into the kernel or say M to compile it as module. +config NFC_TRF7970A + tristate "Texas Instruments TRF7970a NFC driver" + depends on SPI && NFC_DIGITAL + help + This option enables the NFC driver for Texas Instruments' TRF7970a + device. Such device supports 5 different protocols: ISO14443A, + ISO14443B, FeLiCa, ISO15693 and ISO18000-3. + + Say Y here to compile support for TRF7970a into the kernel or + say M to compile it as a module. The module will be called + trf7970a.ko. + config NFC_MEI_PHY tristate "MEI bus NFC device support" depends on INTEL_MEI && NFC_HCI diff --git a/drivers/nfc/Makefile b/drivers/nfc/Makefile index 56ab822ba03d..ae42a3fa60c9 100644 --- a/drivers/nfc/Makefile +++ b/drivers/nfc/Makefile @@ -10,5 +10,6 @@ obj-$(CONFIG_NFC_MEI_PHY) += mei_phy.o obj-$(CONFIG_NFC_SIM) += nfcsim.o obj-$(CONFIG_NFC_PORT100) += port100.o obj-$(CONFIG_NFC_MRVL) += nfcmrvl/ +obj-$(CONFIG_NFC_TRF7970A) += trf7970a.o ccflags-$(CONFIG_NFC_DEBUG) := -DDEBUG diff --git a/drivers/nfc/trf7970a.c b/drivers/nfc/trf7970a.c new file mode 100644 index 000000000000..0d62d45d6884 --- /dev/null +++ b/drivers/nfc/trf7970a.c @@ -0,0 +1,1224 @@ +/* + * TI TRF7970a RFID/NFC Transceiver Driver + * + * Copyright (C) 2013 Texas Instruments Incorporated - http://www.ti.com + * + * Author: Erick Macias <emacias@ti.com> + * Author: Felipe Balbi <balbi@ti.com> + * Author: Mark A. Greer <mgreer@animalcreek.com> + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 of + * the License as published by the Free Software Foundation. + */ + +#include <linux/module.h> +#include <linux/device.h> +#include <linux/netdevice.h> +#include <linux/interrupt.h> +#include <linux/nfc.h> +#include <linux/skbuff.h> +#include <linux/delay.h> +#include <linux/gpio.h> +#include <linux/of.h> +#include <linux/of_gpio.h> +#include <linux/spi/spi.h> +#include <linux/regulator/consumer.h> + +#include <net/nfc/nfc.h> +#include <net/nfc/digital.h> + +/* There are 3 ways the host can communicate with the trf7970a: + * parallel mode, SPI with Slave Select (SS) mode, and SPI without + * SS mode. The driver only supports the two SPI modes. + * + * The trf7970a is very timing sensitive and the VIN, EN2, and EN + * pins must asserted in that order and with specific delays in between. + * The delays used in the driver were provided by TI and have been + * confirmed to work with this driver. + * + * Timeouts are implemented using the delayed workqueue kernel facility. + * Timeouts are required so things don't hang when there is no response + * from the trf7970a (or tag). Using this mechanism creates a race with + * interrupts, however. That is, an interrupt and a timeout could occur + * closely enough together that one is blocked by the mutex while the other + * executes. When the timeout handler executes first and blocks the + * interrupt handler, it will eventually set the state to IDLE so the + * interrupt handler will check the state and exit with no harm done. + * When the interrupt handler executes first and blocks the timeout handler, + * the cancel_delayed_work() call will know that it didn't cancel the + * work item (i.e., timeout) and will return zero. That return code is + * used by the timer handler to indicate that it should ignore the timeout + * once its unblocked. + * + * Aborting an active command isn't as simple as it seems because the only + * way to abort a command that's already been sent to the tag is so turn + * off power to the tag. If we do that, though, we'd have to go through + * the entire anticollision procedure again but the digital layer doesn't + * support that. So, if an abort is received before trf7970a_in_send_cmd() + * has sent the command to the tag, it simply returns -ECANCELED. If the + * command has already been sent to the tag, then the driver continues + * normally and recieves the response data (or error) but just before + * sending the data upstream, it frees the rx_skb and sends -ECANCELED + * upstream instead. If the command failed, that error will be sent + * upstream. + * + * When recieving data from a tag and the interrupt status register has + * only the SRX bit set, it means that all of the data has been received + * (once what's in the fifo has been read). However, depending on timing + * an interrupt status with only the SRX bit set may not be recived. In + * those cases, the timeout mechanism is used to wait 5 ms in case more + * data arrives. After 5 ms, it is assumed that all of the data has been + * received and the accumulated rx data is sent upstream. The + * 'TRF7970A_ST_WAIT_FOR_RX_DATA_CONT' state is used for this purpose + * (i.e., it indicates that some data has been received but we're not sure + * if there is more coming so a timeout in this state means all data has + * been received and there isn't an error). The delay is 5 ms since delays + * over 2 ms have been observed during testing (a little extra just in case). + * + * Type 2 write and sector select commands respond with a 4-bit ACK or NACK. + * Having only 4 bits in the FIFO won't normally generate an interrupt so + * driver enables the '4_bit_RX' bit of the Special Functions register 1 + * to cause an interrupt in that case. Leaving that bit for a read command + * messes up the data returned so it is only enabled when the framing is + * 'NFC_DIGITAL_FRAMING_NFCA_T2T' and the command is not a read command. + * Unfortunately, that means that the driver has to peek into tx frames + * when the framing is 'NFC_DIGITAL_FRAMING_NFCA_T2T'. This is done by + * the trf7970a_per_cmd_config() routine. + */ + +#define TRF7970A_SUPPORTED_PROTOCOLS NFC_PROTO_MIFARE_MASK + +/* TX data must be prefixed with a FIFO reset cmd, a cmd that depends + * on what the current framing is, the address of the TX length byte 1 + * register (0x1d), and the 2 byte length of the data to be transmitted. + * That totals 5 bytes. + */ +#define TRF7970A_TX_SKB_HEADROOM 5 + +#define TRF7970A_RX_SKB_ALLOC_SIZE 256 + +#define TRF7970A_FIFO_SIZE 128 + +/* TX length is 3 nibbles long ==> 4KB - 1 bytes max */ +#define TRF7970A_TX_MAX (4096 - 1) + +#define TRF7970A_WAIT_FOR_RX_DATA_TIMEOUT 5 +#define TRF7970A_WAIT_FOR_FIFO_DRAIN_TIMEOUT 3 + +/* Quirks */ +/* Erratum: When reading IRQ Status register on trf7970a, we must issue a + * read continuous command for IRQ Status and Collision Position registers. + */ +#define TRF7970A_QUIRK_IRQ_STATUS_READ_ERRATA BIT(0) + +/* Direct commands */ +#define TRF7970A_CMD_IDLE 0x00 +#define TRF7970A_CMD_SOFT_INIT 0x03 +#define TRF7970A_CMD_RF_COLLISION 0x04 +#define TRF7970A_CMD_RF_COLLISION_RESPONSE_N 0x05 +#define TRF7970A_CMD_RF_COLLISION_RESPONSE_0 0x06 +#define TRF7970A_CMD_FIFO_RESET 0x0f +#define TRF7970A_CMD_TRANSMIT_NO_CRC 0x10 +#define TRF7970A_CMD_TRANSMIT 0x11 +#define TRF7970A_CMD_DELAY_TRANSMIT_NO_CRC 0x12 +#define TRF7970A_CMD_DELAY_TRANSMIT 0x13 +#define TRF7970A_CMD_EOF 0x14 +#define TRF7970A_CMD_CLOSE_SLOT 0x15 +#define TRF7970A_CMD_BLOCK_RX 0x16 +#define TRF7970A_CMD_ENABLE_RX 0x17 +#define TRF7970A_CMD_TEST_EXT_RF 0x18 +#define TRF7970A_CMD_TEST_INT_RF 0x19 +#define TRF7970A_CMD_RX_GAIN_ADJUST 0x1a + +/* Bits determining whether its a direct command or register R/W, + * whether to use a continuous SPI transaction or not, and the actual + * direct cmd opcode or regster address. + */ +#define TRF7970A_CMD_BIT_CTRL BIT(7) +#define TRF7970A_CMD_BIT_RW BIT(6) +#define TRF7970A_CMD_BIT_CONTINUOUS BIT(5) +#define TRF7970A_CMD_BIT_OPCODE(opcode) ((opcode) & 0x1f) + +/* Registers addresses */ +#define TRF7970A_CHIP_STATUS_CTRL 0x00 +#define TRF7970A_ISO_CTRL 0x01 +#define TRF7970A_ISO14443B_TX_OPTIONS 0x02 +#define TRF7970A_ISO14443A_HIGH_BITRATE_OPTIONS 0x03 +#define TRF7970A_TX_TIMER_SETTING_H_BYTE 0x04 +#define TRF7970A_TX_TIMER_SETTING_L_BYTE 0x05 +#define TRF7970A_TX_PULSE_LENGTH_CTRL 0x06 +#define TRF7970A_RX_NO_RESPONSE_WAIT 0x07 +#define TRF7970A_RX_WAIT_TIME 0x08 +#define TRF7970A_MODULATOR_SYS_CLK_CTRL 0x09 +#define TRF7970A_RX_SPECIAL_SETTINGS 0x0a +#define TRF7970A_REG_IO_CTRL 0x0b +#define TRF7970A_IRQ_STATUS 0x0c +#define TRF7970A_COLLISION_IRQ_MASK 0x0d +#define TRF7970A_COLLISION_POSITION 0x0e +#define TRF7970A_RSSI_OSC_STATUS 0x0f +#define TRF7970A_SPECIAL_FCN_REG1 0x10 +#define TRF7970A_SPECIAL_FCN_REG2 0x11 +#define TRF7970A_RAM1 0x12 +#define TRF7970A_RAM2 0x13 +#define TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS 0x14 +#define TRF7970A_NFC_LOW_FIELD_LEVEL 0x16 +#define TRF7970A_NFCID1 0x17 +#define TRF7970A_NFC_TARGET_LEVEL 0x18 +#define TRF79070A_NFC_TARGET_PROTOCOL 0x19 +#define TRF7970A_TEST_REGISTER1 0x1a +#define TRF7970A_TEST_REGISTER2 0x1b +#define TRF7970A_FIFO_STATUS 0x1c +#define TRF7970A_TX_LENGTH_BYTE1 0x1d +#define TRF7970A_TX_LENGTH_BYTE2 0x1e +#define TRF7970A_FIFO_IO_REGISTER 0x1f + +/* Chip Status Control Register Bits */ +#define TRF7970A_CHIP_STATUS_VRS5_3 BIT(0) +#define TRF7970A_CHIP_STATUS_REC_ON BIT(1) +#define TRF7970A_CHIP_STATUS_AGC_ON BIT(2) +#define TRF7970A_CHIP_STATUS_PM_ON BIT(3) +#define TRF7970A_CHIP_STATUS_RF_PWR BIT(4) +#define TRF7970A_CHIP_STATUS_RF_ON BIT(5) +#define TRF7970A_CHIP_STATUS_DIRECT BIT(6) +#define TRF7970A_CHIP_STATUS_STBY BIT(7) + +/* ISO Control Register Bits */ +#define TRF7970A_ISO_CTRL_15693_SGL_1OF4_662 0x00 +#define TRF7970A_ISO_CTRL_15693_SGL_1OF256_662 0x01 +#define TRF7970A_ISO_CTRL_15693_SGL_1OF4_2648 0x02 +#define TRF7970A_ISO_CTRL_15693_SGL_1OF256_2648 0x03 +#define TRF7970A_ISO_CTRL_15693_DBL_1OF4_667a 0x04 +#define TRF7970A_ISO_CTRL_15693_DBL_1OF256_667 0x05 +#define TRF7970A_ISO_CTRL_15693_DBL_1OF4_2669 0x06 +#define TRF7970A_ISO_CTRL_15693_DBL_1OF256_2669 0x07 +#define TRF7970A_ISO_CTRL_14443A_106 0x08 +#define TRF7970A_ISO_CTRL_14443A_212 0x09 +#define TRF7970A_ISO_CTRL_14443A_424 0x0a +#define TRF7970A_ISO_CTRL_14443A_848 0x0b +#define TRF7970A_ISO_CTRL_14443B_106 0x0c +#define TRF7970A_ISO_CTRL_14443B_212 0x0d +#define TRF7970A_ISO_CTRL_14443B_424 0x0e +#define TRF7970A_ISO_CTRL_14443B_848 0x0f +#define TRF7970A_ISO_CTRL_FELICA_212 0x1a +#define TRF7970A_ISO_CTRL_FELICA_424 0x1b +#define TRF7970A_ISO_CTRL_RFID BIT(5) +#define TRF7970A_ISO_CTRL_DIR_MODE BIT(6) +#define TRF7970A_ISO_CTRL_RX_CRC_N BIT(7) /* true == No CRC */ + +#define TRF7970A_ISO_CTRL_RFID_SPEED_MASK 0x1f + +/* Modulator and SYS_CLK Control Register Bits */ +#define TRF7970A_MODULATOR_DEPTH(n) ((n) & 0x7) +#define TRF7970A_MODULATOR_DEPTH_ASK10 (TRF7970A_MODULATOR_DEPTH(0)) +#define TRF7970A_MODULATOR_DEPTH_OOK (TRF7970A_MODULATOR_DEPTH(1)) +#define TRF7970A_MODULATOR_DEPTH_ASK7 (TRF7970A_MODULATOR_DEPTH(2)) +#define TRF7970A_MODULATOR_DEPTH_ASK8_5 (TRF7970A_MODULATOR_DEPTH(3)) +#define TRF7970A_MODULATOR_DEPTH_ASK13 (TRF7970A_MODULATOR_DEPTH(4)) +#define TRF7970A_MODULATOR_DEPTH_ASK16 (TRF7970A_MODULATOR_DEPTH(5)) +#define TRF7970A_MODULATOR_DEPTH_ASK22 (TRF7970A_MODULATOR_DEPTH(6)) +#define TRF7970A_MODULATOR_DEPTH_ASK30 (TRF7970A_MODULATOR_DEPTH(7)) +#define TRF7970A_MODULATOR_EN_ANA BIT(3) +#define TRF7970A_MODULATOR_CLK(n) (((n) & 0x3) << 4) +#define TRF7970A_MODULATOR_CLK_DISABLED (TRF7970A_MODULATOR_CLK(0)) +#define TRF7970A_MODULATOR_CLK_3_6 (TRF7970A_MODULATOR_CLK(1)) +#define TRF7970A_MODULATOR_CLK_6_13 (TRF7970A_MODULATOR_CLK(2)) +#define TRF7970A_MODULATOR_CLK_13_27 (TRF7970A_MODULATOR_CLK(3)) +#define TRF7970A_MODULATOR_EN_OOK BIT(6) +#define TRF7970A_MODULATOR_27MHZ BIT(7) + +/* IRQ Status Register Bits */ +#define TRF7970A_IRQ_STATUS_NORESP BIT(0) /* ISO15693 only */ +#define TRF7970A_IRQ_STATUS_COL BIT(1) +#define TRF7970A_IRQ_STATUS_FRAMING_EOF_ERROR BIT(2) +#define TRF7970A_IRQ_STATUS_PARITY_ERROR BIT(3) +#define TRF7970A_IRQ_STATUS_CRC_ERROR BIT(4) +#define TRF7970A_IRQ_STATUS_FIFO BIT(5) +#define TRF7970A_IRQ_STATUS_SRX BIT(6) +#define TRF7970A_IRQ_STATUS_TX BIT(7) + +#define TRF7970A_IRQ_STATUS_ERROR \ + (TRF7970A_IRQ_STATUS_COL | \ + TRF7970A_IRQ_STATUS_FRAMING_EOF_ERROR | \ + TRF7970A_IRQ_STATUS_PARITY_ERROR | \ + TRF7970A_IRQ_STATUS_CRC_ERROR) + +#define TRF7970A_SPECIAL_FCN_REG1_COL_7_6 BIT(0) +#define TRF7970A_SPECIAL_FCN_REG1_14_ANTICOLL BIT(1) +#define TRF7970A_SPECIAL_FCN_REG1_4_BIT_RX BIT(2) +#define TRF7970A_SPECIAL_FCN_REG1_SP_DIR_MODE BIT(3) +#define TRF7970A_SPECIAL_FCN_REG1_NEXT_SLOT_37US BIT(4) +#define TRF7970A_SPECIAL_FCN_REG1_PAR43 BIT(5) + +#define TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLH_124 (0x0 << 2) +#define TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLH_120 (0x1 << 2) +#define TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLH_112 (0x2 << 2) +#define TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLH_96 (0x3 << 2) +#define TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLL_4 0x0 +#define TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLL_8 0x1 +#define TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLL_16 0x2 +#define TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLL_32 0x3 + +#define TRF7970A_FIFO_STATUS_OVERFLOW BIT(7) + +/* NFC (ISO/IEC 14443A) Type 2 Tag commands */ +#define NFC_T2T_CMD_READ 0x30 + +enum trf7970a_state { + TRF7970A_ST_OFF, + TRF7970A_ST_IDLE, + TRF7970A_ST_IDLE_RX_BLOCKED, + TRF7970A_ST_WAIT_FOR_TX_FIFO, + TRF7970A_ST_WAIT_FOR_RX_DATA, + TRF7970A_ST_WAIT_FOR_RX_DATA_CONT, + TRF7970A_ST_MAX +}; + +struct trf7970a { + enum trf7970a_state state; + struct device *dev; + struct spi_device *spi; + struct regulator *regulator; + struct nfc_digital_dev *ddev; + u32 quirks; + bool powering_up; + bool aborting; + struct sk_buff *tx_skb; + struct sk_buff *rx_skb; + nfc_digital_cmd_complete_t cb; + void *cb_arg; + u8 iso_ctrl; + u8 special_fcn_reg1; + int technology; + int framing; + u8 tx_cmd; + int en2_gpio; + int en_gpio; + struct mutex lock; + unsigned int timeout; + bool ignore_timeout; + struct delayed_work timeout_work; +}; + + +static int trf7970a_cmd(struct trf7970a *trf, u8 opcode) +{ + u8 cmd = TRF7970A_CMD_BIT_CTRL | TRF7970A_CMD_BIT_OPCODE(opcode); + int ret; + + dev_dbg(trf->dev, "cmd: 0x%x\n", cmd); + + ret = spi_write(trf->spi, &cmd, 1); + if (ret) + dev_err(trf->dev, "%s - cmd: 0x%x, ret: %d\n", __func__, cmd, + ret); + return ret; +} + +static int trf7970a_read(struct trf7970a *trf, u8 reg, u8 *val) +{ + u8 addr = TRF7970A_CMD_BIT_RW | reg; + int ret; + + ret = spi_write_then_read(trf->spi, &addr, 1, val, 1); + if (ret) + dev_err(trf->dev, "%s - addr: 0x%x, ret: %d\n", __func__, addr, + ret); + + dev_dbg(trf->dev, "read(0x%x): 0x%x\n", addr, *val); + + return ret; +} + +static int trf7970a_read_cont(struct trf7970a *trf, u8 reg, + u8 *buf, size_t len) +{ + u8 addr = reg | TRF7970A_CMD_BIT_RW | TRF7970A_CMD_BIT_CONTINUOUS; + int ret; + + dev_dbg(trf->dev, "read_cont(0x%x, %zd)\n", addr, len); + + ret = spi_write_then_read(trf->spi, &addr, 1, buf, len); + if (ret) + dev_err(trf->dev, "%s - addr: 0x%x, ret: %d\n", __func__, addr, + ret); + return ret; +} + +static int trf7970a_write(struct trf7970a *trf, u8 reg, u8 val) +{ + u8 buf[2] = { reg, val }; + int ret; + + dev_dbg(trf->dev, "write(0x%x): 0x%x\n", reg, val); + + ret = spi_write(trf->spi, buf, 2); + if (ret) + dev_err(trf->dev, "%s - write: 0x%x 0x%x, ret: %d\n", __func__, + buf[0], buf[1], ret); + + return ret; +} + +static int trf7970a_read_irqstatus(struct trf7970a *trf, u8 *status) +{ + int ret; + u8 buf[2]; + u8 addr; + + addr = TRF7970A_IRQ_STATUS | TRF7970A_CMD_BIT_RW; + + if (trf->quirks & TRF7970A_QUIRK_IRQ_STATUS_READ_ERRATA) { + addr |= TRF7970A_CMD_BIT_CONTINUOUS; + ret = spi_write_then_read(trf->spi, &addr, 1, buf, 2); + } else { + ret = spi_write_then_read(trf->spi, &addr, 1, buf, 1); + } + + if (ret) + dev_err(trf->dev, "%s - irqstatus: Status read failed: %d\n", + __func__, ret); + else + *status = buf[0]; + + return ret; +} + +static void trf7970a_send_upstream(struct trf7970a *trf) +{ + u8 rssi; + + dev_kfree_skb_any(trf->tx_skb); + trf->tx_skb = NULL; + + if (trf->rx_skb && !IS_ERR(trf->rx_skb) && !trf->aborting) + print_hex_dump_debug("trf7970a rx data: ", DUMP_PREFIX_NONE, + 16, 1, trf->rx_skb->data, trf->rx_skb->len, + false); + + /* According to the manual it is "good form" to reset the fifo and + * read the RSSI levels & oscillator status register here. It doesn't + * explain why. + */ + trf7970a_cmd(trf, TRF7970A_CMD_FIFO_RESET); + trf7970a_read(trf, TRF7970A_RSSI_OSC_STATUS, &rssi); + + trf->state = TRF7970A_ST_IDLE; + + if (trf->aborting) { + dev_dbg(trf->dev, "Abort process complete\n"); + + if (!IS_ERR(trf->rx_skb)) { + kfree_skb(trf->rx_skb); + trf->rx_skb = ERR_PTR(-ECANCELED); + } + + trf->aborting = false; + } + + trf->cb(trf->ddev, trf->cb_arg, trf->rx_skb); + + trf->rx_skb = NULL; +} + +static void trf7970a_send_err_upstream(struct trf7970a *trf, int errno) +{ + dev_dbg(trf->dev, "Error - state: %d, errno: %d\n", trf->state, errno); + + kfree_skb(trf->rx_skb); + trf->rx_skb = ERR_PTR(errno); + + trf7970a_send_upstream(trf); +} + +static int trf7970a_transmit(struct trf7970a *trf, struct sk_buff *skb, + unsigned int len) +{ + unsigned int timeout; + int ret; + + print_hex_dump_debug("trf7970a tx data: ", DUMP_PREFIX_NONE, + 16, 1, skb->data, len, false); + + ret = spi_write(trf->spi, skb->data, len); + if (ret) { + dev_err(trf->dev, "%s - Can't send tx data: %d\n", __func__, + ret); + return ret; + } + + skb_pull(skb, len); + + if (skb->len > 0) { + trf->state = TRF7970A_ST_WAIT_FOR_TX_FIFO; + timeout = TRF7970A_WAIT_FOR_FIFO_DRAIN_TIMEOUT; + } else { + trf->state = TRF7970A_ST_WAIT_FOR_RX_DATA; + timeout = trf->timeout; + } + + dev_dbg(trf->dev, "Setting timeout for %d ms, state: %d\n", timeout, + trf->state); + + schedule_delayed_work(&trf->timeout_work, msecs_to_jiffies(timeout)); + + return 0; +} + +static void trf7970a_fill_fifo(struct trf7970a *trf) +{ + struct sk_buff *skb = trf->tx_skb; + unsigned int len; + int ret; + u8 fifo_bytes; + + ret = trf7970a_read(trf, TRF7970A_FIFO_STATUS, &fifo_bytes); + if (ret) { + trf7970a_send_err_upstream(trf, ret); + return; + } + + dev_dbg(trf->dev, "Filling FIFO - fifo_bytes: 0x%x\n", fifo_bytes); + + if (fifo_bytes & TRF7970A_FIFO_STATUS_OVERFLOW) { + dev_err(trf->dev, "%s - fifo overflow: 0x%x\n", __func__, + fifo_bytes); + trf7970a_send_err_upstream(trf, -EIO); + return; + } + + /* Calculate how much more data can be written to the fifo */ + len = TRF7970A_FIFO_SIZE - fifo_bytes; + len = min(skb->len, len); + + ret = trf7970a_transmit(trf, skb, len); + if (ret) + trf7970a_send_err_upstream(trf, ret); +} + +static void trf7970a_drain_fifo(struct trf7970a *trf, u8 status) +{ + struct sk_buff *skb = trf->rx_skb; + int ret; + u8 fifo_bytes; + + if (status & TRF7970A_IRQ_STATUS_ERROR) { + trf7970a_send_err_upstream(trf, -EIO); + return; + } + + ret = trf7970a_read(trf, TRF7970A_FIFO_STATUS, &fifo_bytes); + if (ret) { + trf7970a_send_err_upstream(trf, ret); + return; + } + + dev_dbg(trf->dev, "Draining FIFO - fifo_bytes: 0x%x\n", fifo_bytes); + + if (!fifo_bytes) + goto no_rx_data; + + if (fifo_bytes & TRF7970A_FIFO_STATUS_OVERFLOW) { + dev_err(trf->dev, "%s - fifo overflow: 0x%x\n", __func__, + fifo_bytes); + trf7970a_send_err_upstream(trf, -EIO); + return; + } + + if (fifo_bytes > skb_tailroom(skb)) { + skb = skb_copy_expand(skb, skb_headroom(skb), + max_t(int, fifo_bytes, + TRF7970A_RX_SKB_ALLOC_SIZE), + GFP_KERNEL); + if (!skb) { + trf7970a_send_err_upstream(trf, -ENOMEM); + return; + } + + kfree_skb(trf->rx_skb); + trf->rx_skb = skb; + } + + ret = trf7970a_read_cont(trf, TRF7970A_FIFO_IO_REGISTER, + skb_put(skb, fifo_bytes), fifo_bytes); + if (ret) { + trf7970a_send_err_upstream(trf, ret); + return; + } + + /* If received Type 2 ACK/NACK, shift right 4 bits and pass up */ + if ((trf->framing == NFC_DIGITAL_FRAMING_NFCA_T2T) && (skb->len == 1) && + (trf->special_fcn_reg1 == + TRF7970A_SPECIAL_FCN_REG1_4_BIT_RX)) { + skb->data[0] >>= 4; + status = TRF7970A_IRQ_STATUS_SRX; + } else { + trf->state = TRF7970A_ST_WAIT_FOR_RX_DATA_CONT; + } + +no_rx_data: + if (status == TRF7970A_IRQ_STATUS_SRX) { /* Receive complete */ + trf7970a_send_upstream(trf); + return; + } + + dev_dbg(trf->dev, "Setting timeout for %d ms\n", + TRF7970A_WAIT_FOR_RX_DATA_TIMEOUT); + + schedule_delayed_work(&trf->timeout_work, + msecs_to_jiffies(TRF7970A_WAIT_FOR_RX_DATA_TIMEOUT)); +} + +static irqreturn_t trf7970a_irq(int irq, void *dev_id) +{ + struct trf7970a *trf = dev_id; + int ret; + u8 status; + + mutex_lock(&trf->lock); + + if (trf->state == TRF7970A_ST_OFF) { + mutex_unlock(&trf->lock); + return IRQ_NONE; + } + + ret = trf7970a_read_irqstatus(trf, &status); + if (ret) { + mutex_unlock(&trf->lock); + return IRQ_NONE; + } + + dev_dbg(trf->dev, "IRQ - state: %d, status: 0x%x\n", trf->state, + status); + + if (!status) { + mutex_unlock(&trf->lock); + return IRQ_NONE; + } + + switch (trf->state) { + case TRF7970A_ST_IDLE: + case TRF7970A_ST_IDLE_RX_BLOCKED: + /* If getting interrupts caused by RF noise, turn off the + * receiver to avoid unnecessary interrupts. It will be + * turned back on in trf7970a_in_send_cmd() when the next + * command is issued. + */ + if (status & TRF7970A_IRQ_STATUS_ERROR) { + trf7970a_cmd(trf, TRF7970A_CMD_BLOCK_RX); + trf->state = TRF7970A_ST_IDLE_RX_BLOCKED; + } + + trf7970a_cmd(trf, TRF7970A_CMD_FIFO_RESET); + break; + case TRF7970A_ST_WAIT_FOR_TX_FIFO: + if (status & TRF7970A_IRQ_STATUS_TX) { + trf->ignore_timeout = + !cancel_delayed_work(&trf->timeout_work); + trf7970a_fill_fifo(trf); + } else { + trf7970a_send_err_upstream(trf, -EIO); + } + break; + case TRF7970A_ST_WAIT_FOR_RX_DATA: + case TRF7970A_ST_WAIT_FOR_RX_DATA_CONT: + if (status & TRF7970A_IRQ_STATUS_SRX) { + trf->ignore_timeout = + !cancel_delayed_work(&trf->timeout_work); + trf7970a_drain_fifo(trf, status); + } else if (!(status & TRF7970A_IRQ_STATUS_TX)) { + trf7970a_send_err_upstream(trf, -EIO); + } + break; + default: + dev_err(trf->dev, "%s - Driver in invalid state: %d\n", + __func__, trf->state); + } + + mutex_unlock(&trf->lock); + return IRQ_HANDLED; +} + +static void trf7970a_timeout_work_handler(struct work_struct *work) +{ + struct trf7970a *trf = container_of(work, struct trf7970a, + timeout_work.work); + + dev_dbg(trf->dev, "Timeout - state: %d, ignore_timeout: %d\n", + trf->state, trf->ignore_timeout); + + mutex_lock(&trf->lock); + + if (trf->ignore_timeout) + trf->ignore_timeout = false; + else if (trf->state == TRF7970A_ST_WAIT_FOR_RX_DATA_CONT) + trf7970a_send_upstream(trf); /* No more rx data so send up */ + else + trf7970a_send_err_upstream(trf, -ETIMEDOUT); + + mutex_unlock(&trf->lock); +} + +static int trf7970a_init(struct trf7970a *trf) +{ + int ret; + + dev_dbg(trf->dev, "Initializing device - state: %d\n", trf->state); + + ret = trf7970a_cmd(trf, TRF7970A_CMD_SOFT_INIT); + if (ret) + goto err_out; + + ret = trf7970a_cmd(trf, TRF7970A_CMD_IDLE); + if (ret) + goto err_out; + + ret = trf7970a_write(trf, TRF7970A_MODULATOR_SYS_CLK_CTRL, + TRF7970A_MODULATOR_DEPTH_OOK); + if (ret) + goto err_out; + + ret = trf7970a_write(trf, TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS, + TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLH_96 | + TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLL_32); + if (ret) + goto err_out; + + ret = trf7970a_write(trf, TRF7970A_SPECIAL_FCN_REG1, 0); + if (ret) + goto err_out; + + trf->special_fcn_reg1 = 0; + + ret = trf7970a_write(trf, TRF7970A_CHIP_STATUS_CTRL, + TRF7970A_CHIP_STATUS_RF_ON | + TRF7970A_CHIP_STATUS_VRS5_3); + if (ret) + goto err_out; + + return 0; + +err_out: + dev_dbg(trf->dev, "Couldn't init device: %d\n", ret); + return ret; +} + +static void trf7970a_switch_rf_off(struct trf7970a *trf) +{ + dev_dbg(trf->dev, "Switching rf off\n"); + + gpio_set_value(trf->en_gpio, 0); + gpio_set_value(trf->en2_gpio, 0); + + trf->aborting = false; + trf->state = TRF7970A_ST_OFF; +} + +static int trf7970a_switch_rf_on(struct trf7970a *trf) +{ + unsigned long delay; + int ret; + + dev_dbg(trf->dev, "Switching rf on\n"); + + if (trf->powering_up) + usleep_range(5000, 6000); + + gpio_set_value(trf->en2_gpio, 1); + usleep_range(1000, 2000); + gpio_set_value(trf->en_gpio, 1); + + /* The delay between enabling the trf7970a and issuing the first + * command is significantly longer the very first time after powering + * up. Make sure the longer delay is only done the first time. + */ + if (trf->powering_up) { + delay = 20000; + trf->powering_up = false; + } else { + delay = 5000; + } + + usleep_range(delay, delay + 1000); + + ret = trf7970a_init(trf); + if (ret) + trf7970a_switch_rf_off(trf); + else + trf->state = TRF7970A_ST_IDLE; + + return ret; +} + +static int trf7970a_switch_rf(struct nfc_digital_dev *ddev, bool on) +{ + struct trf7970a *trf = nfc_digital_get_drvdata(ddev); + int ret = 0; + + dev_dbg(trf->dev, "Switching RF - state: %d, on: %d\n", trf->state, on); + + mutex_lock(&trf->lock); + + if (on) { + switch (trf->state) { + case TRF7970A_ST_OFF: + ret = trf7970a_switch_rf_on(trf); + break; + case TRF7970A_ST_IDLE: + case TRF7970A_ST_IDLE_RX_BLOCKED: + break; + default: + dev_err(trf->dev, "%s - Invalid request: %d %d\n", + __func__, trf->state, on); + trf7970a_switch_rf_off(trf); + } + } else { + switch (trf->state) { + case TRF7970A_ST_OFF: + break; + default: + dev_err(trf->dev, "%s - Invalid request: %d %d\n", + __func__, trf->state, on); + /* FALLTHROUGH */ + case TRF7970A_ST_IDLE: + case TRF7970A_ST_IDLE_RX_BLOCKED: + trf7970a_switch_rf_off(trf); + } + } + + mutex_unlock(&trf->lock); + return ret; +} + +static int trf7970a_config_rf_tech(struct trf7970a *trf, int tech) +{ + int ret = 0; + + dev_dbg(trf->dev, "rf technology: %d\n", tech); + + switch (tech) { + case NFC_DIGITAL_RF_TECH_106A: + trf->iso_ctrl = TRF7970A_ISO_CTRL_14443A_106; + break; + default: + dev_dbg(trf->dev, "Unsupported rf technology: %d\n", tech); + return -EINVAL; + } + + trf->technology = tech; + + return ret; +} + +static int trf7970a_config_framing(struct trf7970a *trf, int framing) +{ + dev_dbg(trf->dev, "framing: %d\n", framing); + + switch (framing) { + case NFC_DIGITAL_FRAMING_NFCA_SHORT: + case NFC_DIGITAL_FRAMING_NFCA_STANDARD: + trf->tx_cmd = TRF7970A_CMD_TRANSMIT_NO_CRC; + trf->iso_ctrl |= TRF7970A_ISO_CTRL_RX_CRC_N; + break; + case NFC_DIGITAL_FRAMING_NFCA_STANDARD_WITH_CRC_A: + trf->tx_cmd = TRF7970A_CMD_TRANSMIT; + trf->iso_ctrl &= ~TRF7970A_ISO_CTRL_RX_CRC_N; + break; + case NFC_DIGITAL_FRAMING_NFCA_T2T: + trf->tx_cmd = TRF7970A_CMD_TRANSMIT; + trf->iso_ctrl |= TRF7970A_ISO_CTRL_RX_CRC_N; + break; + default: + dev_dbg(trf->dev, "Unsupported Framing: %d\n", framing); + return -EINVAL; + } + + trf->framing = framing; + + return trf7970a_write(trf, TRF7970A_ISO_CTRL, trf->iso_ctrl); +} + +static int trf7970a_in_configure_hw(struct nfc_digital_dev *ddev, int type, + int param) +{ + struct trf7970a *trf = nfc_digital_get_drvdata(ddev); + int ret = 0; + + dev_dbg(trf->dev, "Configure hw - type: %d, param: %d\n", type, param); + + mutex_lock(&trf->lock); + + if (trf->state == TRF7970A_ST_OFF) { + ret = trf7970a_switch_rf_on(trf); + if (ret) + goto err_out; + } + + switch (type) { + case NFC_DIGITAL_CONFIG_RF_TECH: + ret = trf7970a_config_rf_tech(trf, param); + break; + case NFC_DIGITAL_CONFIG_FRAMING: + ret = trf7970a_config_framing(trf, param); + break; + default: + dev_dbg(trf->dev, "Unknown type: %d\n", type); + ret = -EINVAL; + } + +err_out: + mutex_unlock(&trf->lock); + return ret; +} + +static int trf7970a_per_cmd_config(struct trf7970a *trf, struct sk_buff *skb) +{ + u8 *req = skb->data; + u8 special_fcn_reg1; + int ret; + + /* When issuing Type 2 read command, make sure the '4_bit_RX' bit in + * special functions register 1 is cleared; otherwise, its a write or + * sector select command and '4_bit_RX' must be set. + */ + if ((trf->technology == NFC_DIGITAL_RF_TECH_106A) && + (trf->framing == NFC_DIGITAL_FRAMING_NFCA_T2T)) { + if (req[0] == NFC_T2T_CMD_READ) + special_fcn_reg1 = 0; + else + special_fcn_reg1 = TRF7970A_SPECIAL_FCN_REG1_4_BIT_RX; + + if (special_fcn_reg1 != trf->special_fcn_reg1) { + ret = trf7970a_write(trf, TRF7970A_SPECIAL_FCN_REG1, + special_fcn_reg1); + if (ret) + return ret; + + trf->special_fcn_reg1 = special_fcn_reg1; + } + } + + return 0; +} + +static int trf7970a_in_send_cmd(struct nfc_digital_dev *ddev, + struct sk_buff *skb, u16 timeout, + nfc_digital_cmd_complete_t cb, void *arg) +{ + struct trf7970a *trf = nfc_digital_get_drvdata(ddev); + char *prefix; + unsigned int len; + int ret; + + dev_dbg(trf->dev, "New request - state: %d, timeout: %d ms, len: %d\n", + trf->state, timeout, skb->len); + + if (skb->len > TRF7970A_TX_MAX) + return -EINVAL; + + mutex_lock(&trf->lock); + + if ((trf->state != TRF7970A_ST_IDLE) && + (trf->state != TRF7970A_ST_IDLE_RX_BLOCKED)) { + dev_err(trf->dev, "%s - Bogus state: %d\n", __func__, + trf->state); + ret = -EIO; + goto out_err; + } + + if (trf->aborting) { + dev_dbg(trf->dev, "Abort process complete\n"); + trf->aborting = false; + ret = -ECANCELED; + goto out_err; + } + + trf->rx_skb = nfc_alloc_recv_skb(TRF7970A_RX_SKB_ALLOC_SIZE, + GFP_KERNEL); + if (!trf->rx_skb) { + dev_dbg(trf->dev, "Can't alloc rx_skb\n"); + ret = -ENOMEM; + goto out_err; + } + + if (trf->state == TRF7970A_ST_IDLE_RX_BLOCKED) { + ret = trf7970a_cmd(trf, TRF7970A_CMD_ENABLE_RX); + if (ret) + goto out_err; + + trf->state = TRF7970A_ST_IDLE; + } + + ret = trf7970a_per_cmd_config(trf, skb); + if (ret) + goto out_err; + + trf->ddev = ddev; + trf->tx_skb = skb; + trf->cb = cb; + trf->cb_arg = arg; + trf->timeout = timeout; + trf->ignore_timeout = false; + + len = skb->len; + prefix = skb_push(skb, TRF7970A_TX_SKB_HEADROOM); + + /* TX data must be prefixed with a FIFO reset cmd, a cmd that depends + * on what the current framing is, the address of the TX length byte 1 + * register (0x1d), and the 2 byte length of the data to be transmitted. + */ + prefix[0] = TRF7970A_CMD_BIT_CTRL | + TRF7970A_CMD_BIT_OPCODE(TRF7970A_CMD_FIFO_RESET); + prefix[1] = TRF7970A_CMD_BIT_CTRL | + TRF7970A_CMD_BIT_OPCODE(trf->tx_cmd); + prefix[2] = TRF7970A_CMD_BIT_CONTINUOUS | TRF7970A_TX_LENGTH_BYTE1; + + if (trf->framing == NFC_DIGITAL_FRAMING_NFCA_SHORT) { + prefix[3] = 0x00; + prefix[4] = 0x0f; /* 7 bits */ + } else { + prefix[3] = (len & 0xf00) >> 4; + prefix[3] |= ((len & 0xf0) >> 4); + prefix[4] = ((len & 0x0f) << 4); + } + + len = min_t(int, skb->len, TRF7970A_FIFO_SIZE); + + usleep_range(1000, 2000); + + ret = trf7970a_transmit(trf, skb, len); + if (ret) { + kfree_skb(trf->rx_skb); + trf->rx_skb = NULL; + } + +out_err: + mutex_unlock(&trf->lock); + return ret; +} + +static int trf7970a_tg_configure_hw(struct nfc_digital_dev *ddev, + int type, int param) +{ + struct trf7970a *trf = nfc_digital_get_drvdata(ddev); + + dev_dbg(trf->dev, "Unsupported interface\n"); + + return -EINVAL; +} + +static int trf7970a_tg_send_cmd(struct nfc_digital_dev *ddev, + struct sk_buff *skb, u16 timeout, + nfc_digital_cmd_complete_t cb, void *arg) +{ + struct trf7970a *trf = nfc_digital_get_drvdata(ddev); + + dev_dbg(trf->dev, "Unsupported interface\n"); + + return -EINVAL; +} + +static int trf7970a_tg_listen(struct nfc_digital_dev *ddev, + u16 timeout, nfc_digital_cmd_complete_t cb, void *arg) +{ + struct trf7970a *trf = nfc_digital_get_drvdata(ddev); + + dev_dbg(trf->dev, "Unsupported interface\n"); + + return -EINVAL; +} + +static int trf7970a_tg_listen_mdaa(struct nfc_digital_dev *ddev, + struct digital_tg_mdaa_params *mdaa_params, + u16 timeout, nfc_digital_cmd_complete_t cb, void *arg) +{ + struct trf7970a *trf = nfc_digital_get_drvdata(ddev); + + dev_dbg(trf->dev, "Unsupported interface\n"); + + return -EINVAL; +} + +static void trf7970a_abort_cmd(struct nfc_digital_dev *ddev) +{ + struct trf7970a *trf = nfc_digital_get_drvdata(ddev); + + dev_dbg(trf->dev, "Abort process initiated\n"); + + mutex_lock(&trf->lock); + trf->aborting = true; + mutex_unlock(&trf->lock); +} + +static struct nfc_digital_ops trf7970a_nfc_ops = { + .in_configure_hw = trf7970a_in_configure_hw, + .in_send_cmd = trf7970a_in_send_cmd, + .tg_configure_hw = trf7970a_tg_configure_hw, + .tg_send_cmd = trf7970a_tg_send_cmd, + .tg_listen = trf7970a_tg_listen, + .tg_listen_mdaa = trf7970a_tg_listen_mdaa, + .switch_rf = trf7970a_switch_rf, + .abort_cmd = trf7970a_abort_cmd, +}; + +static int trf7970a_probe(struct spi_device *spi) +{ + struct device_node *np = spi->dev.of_node; + const struct spi_device_id *id = spi_get_device_id(spi); + struct trf7970a *trf; + int ret; + + if (!np) { + dev_err(&spi->dev, "No Device Tree entry\n"); + return -EINVAL; + } + + trf = devm_kzalloc(&spi->dev, sizeof(*trf), GFP_KERNEL); + if (!trf) + return -ENOMEM; + + trf->state = TRF7970A_ST_OFF; + trf->dev = &spi->dev; + trf->spi = spi; + trf->quirks = id->driver_data; + + spi->mode = SPI_MODE_1; + spi->bits_per_word = 8; + + /* There are two enable pins - both must be present */ + trf->en_gpio = of_get_named_gpio(np, "ti,enable-gpios", 0); + if (!gpio_is_valid(trf->en_gpio)) { + dev_err(trf->dev, "No EN GPIO property\n"); + return trf->en_gpio; + } + + ret = devm_gpio_request_one(trf->dev, trf->en_gpio, + GPIOF_DIR_OUT | GPIOF_INIT_LOW, "EN"); + if (ret) { + dev_err(trf->dev, "Can't request EN GPIO: %d\n", ret); + return ret; + } + + trf->en2_gpio = of_get_named_gpio(np, "ti,enable-gpios", 1); + if (!gpio_is_valid(trf->en2_gpio)) { + dev_err(trf->dev, "No EN2 GPIO property\n"); + return trf->en2_gpio; + } + + ret = devm_gpio_request_one(trf->dev, trf->en2_gpio, + GPIOF_DIR_OUT | GPIOF_INIT_LOW, "EN2"); + if (ret) { + dev_err(trf->dev, "Can't request EN2 GPIO: %d\n", ret); + return ret; + } + + ret = devm_request_threaded_irq(trf->dev, spi->irq, NULL, + trf7970a_irq, IRQF_TRIGGER_RISING | IRQF_ONESHOT, + "trf7970a", trf); + if (ret) { + dev_err(trf->dev, "Can't request IRQ#%d: %d\n", spi->irq, ret); + return ret; + } + + mutex_init(&trf->lock); + INIT_DELAYED_WORK(&trf->timeout_work, trf7970a_timeout_work_handler); + + trf->regulator = devm_regulator_get(&spi->dev, "vin"); + if (IS_ERR(trf->regulator)) { + ret = PTR_ERR(trf->regulator); + dev_err(trf->dev, "Can't get VIN regulator: %d\n", ret); + goto err_destroy_lock; + } + + ret = regulator_enable(trf->regulator); + if (ret) { + dev_err(trf->dev, "Can't enable VIN: %d\n", ret); + goto err_destroy_lock; + } + + trf->powering_up = true; + + trf->ddev = nfc_digital_allocate_device(&trf7970a_nfc_ops, + TRF7970A_SUPPORTED_PROTOCOLS, + NFC_DIGITAL_DRV_CAPS_IN_CRC, TRF7970A_TX_SKB_HEADROOM, + 0); + if (!trf->ddev) { + dev_err(trf->dev, "Can't allocate NFC digital device\n"); + ret = -ENOMEM; + goto err_disable_regulator; + } + + nfc_digital_set_parent_dev(trf->ddev, trf->dev); + nfc_digital_set_drvdata(trf->ddev, trf); + spi_set_drvdata(spi, trf); + + ret = nfc_digital_register_device(trf->ddev); + if (ret) { + dev_err(trf->dev, "Can't register NFC digital device: %d\n", + ret); + goto err_free_ddev; + } + + return 0; + +err_free_ddev: + nfc_digital_free_device(trf->ddev); +err_disable_regulator: + regulator_disable(trf->regulator); +err_destroy_lock: + mutex_destroy(&trf->lock); + return ret; +} + +static int trf7970a_remove(struct spi_device *spi) +{ + struct trf7970a *trf = spi_get_drvdata(spi); + + mutex_lock(&trf->lock); + + trf7970a_switch_rf_off(trf); + trf7970a_init(trf); + + switch (trf->state) { + case TRF7970A_ST_WAIT_FOR_TX_FIFO: + case TRF7970A_ST_WAIT_FOR_RX_DATA: + case TRF7970A_ST_WAIT_FOR_RX_DATA_CONT: + trf7970a_send_err_upstream(trf, -ECANCELED); + break; + default: + break; + } + + mutex_unlock(&trf->lock); + + nfc_digital_unregister_device(trf->ddev); + nfc_digital_free_device(trf->ddev); + + regulator_disable(trf->regulator); + + mutex_destroy(&trf->lock); + + return 0; +} + +static const struct spi_device_id trf7970a_id_table[] = { + { "trf7970a", TRF7970A_QUIRK_IRQ_STATUS_READ_ERRATA }, + { } +}; +MODULE_DEVICE_TABLE(spi, trf7970a_id_table); + +static struct spi_driver trf7970a_spi_driver = { + .probe = trf7970a_probe, + .remove = trf7970a_remove, + .id_table = trf7970a_id_table, + .driver = { + .name = "trf7970a", + .owner = THIS_MODULE, + }, +}; + +module_spi_driver(trf7970a_spi_driver); + +MODULE_AUTHOR("Mark A. Greer <mgreer@animalcreek.com>"); +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("TI trf7970a RFID/NFC Transceiver Driver"); |