/* * TI TRF7970a RFID/NFC Transceiver Driver * * Copyright (C) 2013 Texas Instruments Incorporated - http://www.ti.com * * Author: Erick Macias * Author: Felipe Balbi * Author: Mark A. Greer * * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include /* 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 "); MODULE_LICENSE("GPL v2"); MODULE_DESCRIPTION("TI trf7970a RFID/NFC Transceiver Driver");