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trf7970a.c
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trf7970a.c
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/*
* 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/pm_runtime.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. There is a bug with the current
* version of the trf7970a that requires that EN2 remain low no matter
* what. If it goes high, it will generate an RF field even when in
* passive target mode. TI has indicated that the chip will work okay
* when EN2 is left low. The 'en2-rf-quirk' device tree property
* indicates that trf7970a currently being used has the erratum and
* that EN2 must be kept low.
*
* 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_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 20 ms in case more
* data arrives. After 20 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 20 ms since delays
* of ~16 ms have been observed during testing.
*
* When transmitting a frame larger than the FIFO size (127 bytes), the
* driver will wait 20 ms for the FIFO to drain past the low-watermark
* and generate an interrupt. The low-watermark set to 32 bytes so the
* interrupt should fire after 127 - 32 = 95 bytes have been sent. At
* the lowest possible bit rate (6.62 kbps for 15693), it will take up
* to ~14.35 ms so 20 ms is used for the timeout.
*
* 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.
*
* ISO/IEC 15693 frames specify whether to use single or double sub-carrier
* frequencies and whether to use low or high data rates in the flags byte
* of the frame. This means that the driver has to peek at all 15693 frames
* to determine what speed to set the communication to. In addition, write
* and lock commands use the OPTION flag to indicate that an EOF must be
* sent to the tag before it will send its response. So the driver has to
* examine all frames for that reason too.
*
* It is unclear how long to wait before sending the EOF. According to the
* Note under Table 1-1 in section 1.6 of
* http://www.ti.com/lit/ug/scbu011/scbu011.pdf, that wait should be at least
* 10 ms for TI Tag-it HF-I tags; however testing has shown that is not long
* enough so 20 ms is used. So the timer is set to 40 ms - 20 ms to drain
* up to 127 bytes in the FIFO at the lowest bit rate plus another 20 ms to
* ensure the wait is long enough before sending the EOF. This seems to work
* reliably.
*/
#define TRF7970A_SUPPORTED_PROTOCOLS \
(NFC_PROTO_MIFARE_MASK | NFC_PROTO_ISO14443_MASK | \
NFC_PROTO_ISO14443_B_MASK | NFC_PROTO_FELICA_MASK | \
NFC_PROTO_ISO15693_MASK | NFC_PROTO_NFC_DEP_MASK)
#define TRF7970A_AUTOSUSPEND_DELAY 30000 /* 30 seconds */
#define TRF7970A_RX_SKB_ALLOC_SIZE 256
#define TRF7970A_FIFO_SIZE 127
/* TX length is 3 nibbles long ==> 4KB - 1 bytes max */
#define TRF7970A_TX_MAX (4096 - 1)
#define TRF7970A_WAIT_FOR_TX_IRQ 20
#define TRF7970A_WAIT_FOR_RX_DATA_TIMEOUT 20
#define TRF7970A_WAIT_FOR_FIFO_DRAIN_TIMEOUT 20
#define TRF7970A_WAIT_TO_ISSUE_ISO15693_EOF 40
/* Guard times for various RF technologies (in us) */
#define TRF7970A_GUARD_TIME_NFCA 5000
#define TRF7970A_GUARD_TIME_NFCB 5000
#define TRF7970A_GUARD_TIME_NFCF 20000
#define TRF7970A_GUARD_TIME_15693 1000
/* 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 BIT(0)
#define TRF7970A_QUIRK_EN2_MUST_STAY_LOW BIT(1)
#define TRF7970A_QUIRK_T5T_RMB_EXTRA_BYTE BIT(2)
/* 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_INT_RF 0x18
#define TRF7970A_CMD_TEST_EXT_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_NFC_NFCA_106 0x01
#define TRF7970A_ISO_CTRL_NFC_NFCF_212 0x02
#define TRF7970A_ISO_CTRL_NFC_NFCF_424 0x03
#define TRF7970A_ISO_CTRL_NFC_CE_14443A 0x00
#define TRF7970A_ISO_CTRL_NFC_CE_14443B 0x01
#define TRF7970A_ISO_CTRL_NFC_CE BIT(2)
#define TRF7970A_ISO_CTRL_NFC_ACTIVE BIT(3)
#define TRF7970A_ISO_CTRL_NFC_INITIATOR BIT(4)
#define TRF7970A_ISO_CTRL_NFC_NFC_CE_MODE BIT(5)
#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)
#define TRF7970A_RX_SPECIAL_SETTINGS_NO_LIM BIT(0)
#define TRF7970A_RX_SPECIAL_SETTINGS_AGCR BIT(1)
#define TRF7970A_RX_SPECIAL_SETTINGS_GD_0DB (0x0 << 2)
#define TRF7970A_RX_SPECIAL_SETTINGS_GD_5DB (0x1 << 2)
#define TRF7970A_RX_SPECIAL_SETTINGS_GD_10DB (0x2 << 2)
#define TRF7970A_RX_SPECIAL_SETTINGS_GD_15DB (0x3 << 2)
#define TRF7970A_RX_SPECIAL_SETTINGS_HBT BIT(4)
#define TRF7970A_RX_SPECIAL_SETTINGS_M848 BIT(5)
#define TRF7970A_RX_SPECIAL_SETTINGS_C424 BIT(6)
#define TRF7970A_RX_SPECIAL_SETTINGS_C212 BIT(7)
#define TRF7970A_REG_IO_CTRL_VRS(v) ((v) & 0x07)
#define TRF7970A_REG_IO_CTRL_IO_LOW BIT(5)
#define TRF7970A_REG_IO_CTRL_EN_EXT_PA BIT(6)
#define TRF7970A_REG_IO_CTRL_AUTO_REG BIT(7)
/* IRQ Status Register Bits */
#define TRF7970A_IRQ_STATUS_NORESP BIT(0) /* ISO15693 only */
#define TRF7970A_IRQ_STATUS_NFC_COL_ERROR BIT(0)
#define TRF7970A_IRQ_STATUS_COL BIT(1)
#define TRF7970A_IRQ_STATUS_FRAMING_EOF_ERROR BIT(2)
#define TRF7970A_IRQ_STATUS_NFC_RF BIT(2)
#define TRF7970A_IRQ_STATUS_PARITY_ERROR BIT(3)
#define TRF7970A_IRQ_STATUS_NFC_SDD BIT(3)
#define TRF7970A_IRQ_STATUS_CRC_ERROR BIT(4)
#define TRF7970A_IRQ_STATUS_NFC_PROTO_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_RSSI_OSC_STATUS_RSSI_MASK (BIT(2) | BIT(1) | BIT(0))
#define TRF7970A_RSSI_OSC_STATUS_RSSI_X_MASK (BIT(5) | BIT(4) | BIT(3))
#define TRF7970A_RSSI_OSC_STATUS_RSSI_OSC_OK BIT(6)
#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_NFC_LOW_FIELD_LEVEL_RFDET(v) ((v) & 0x07)
#define TRF7970A_NFC_LOW_FIELD_LEVEL_CLEX_DIS BIT(7)
#define TRF7970A_NFC_TARGET_LEVEL_RFDET(v) ((v) & 0x07)
#define TRF7970A_NFC_TARGET_LEVEL_HI_RF BIT(3)
#define TRF7970A_NFC_TARGET_LEVEL_SDD_EN BIT(5)
#define TRF7970A_NFC_TARGET_LEVEL_LD_S_4BYTES (0x0 << 6)
#define TRF7970A_NFC_TARGET_LEVEL_LD_S_7BYTES (0x1 << 6)
#define TRF7970A_NFC_TARGET_LEVEL_LD_S_10BYTES (0x2 << 6)
#define TRF79070A_NFC_TARGET_PROTOCOL_NFCBR_106 BIT(0)
#define TRF79070A_NFC_TARGET_PROTOCOL_NFCBR_212 BIT(1)
#define TRF79070A_NFC_TARGET_PROTOCOL_NFCBR_424 (BIT(0) | BIT(1))
#define TRF79070A_NFC_TARGET_PROTOCOL_PAS_14443B BIT(2)
#define TRF79070A_NFC_TARGET_PROTOCOL_PAS_106 BIT(3)
#define TRF79070A_NFC_TARGET_PROTOCOL_FELICA BIT(4)
#define TRF79070A_NFC_TARGET_PROTOCOL_RF_L BIT(6)
#define TRF79070A_NFC_TARGET_PROTOCOL_RF_H BIT(7)
#define TRF79070A_NFC_TARGET_PROTOCOL_106A \
(TRF79070A_NFC_TARGET_PROTOCOL_RF_H | \
TRF79070A_NFC_TARGET_PROTOCOL_RF_L | \
TRF79070A_NFC_TARGET_PROTOCOL_PAS_106 | \
TRF79070A_NFC_TARGET_PROTOCOL_NFCBR_106)
#define TRF79070A_NFC_TARGET_PROTOCOL_106B \
(TRF79070A_NFC_TARGET_PROTOCOL_RF_H | \
TRF79070A_NFC_TARGET_PROTOCOL_RF_L | \
TRF79070A_NFC_TARGET_PROTOCOL_PAS_14443B | \
TRF79070A_NFC_TARGET_PROTOCOL_NFCBR_106)
#define TRF79070A_NFC_TARGET_PROTOCOL_212F \
(TRF79070A_NFC_TARGET_PROTOCOL_RF_H | \
TRF79070A_NFC_TARGET_PROTOCOL_RF_L | \
TRF79070A_NFC_TARGET_PROTOCOL_FELICA | \
TRF79070A_NFC_TARGET_PROTOCOL_NFCBR_212)
#define TRF79070A_NFC_TARGET_PROTOCOL_424F \
(TRF79070A_NFC_TARGET_PROTOCOL_RF_H | \
TRF79070A_NFC_TARGET_PROTOCOL_RF_L | \
TRF79070A_NFC_TARGET_PROTOCOL_FELICA | \
TRF79070A_NFC_TARGET_PROTOCOL_NFCBR_424)
#define TRF7970A_FIFO_STATUS_OVERFLOW BIT(7)
/* NFC (ISO/IEC 14443A) Type 2 Tag commands */
#define NFC_T2T_CMD_READ 0x30
/* ISO 15693 commands codes */
#define ISO15693_CMD_INVENTORY 0x01
#define ISO15693_CMD_READ_SINGLE_BLOCK 0x20
#define ISO15693_CMD_WRITE_SINGLE_BLOCK 0x21
#define ISO15693_CMD_LOCK_BLOCK 0x22
#define ISO15693_CMD_READ_MULTIPLE_BLOCK 0x23
#define ISO15693_CMD_WRITE_MULTIPLE_BLOCK 0x24
#define ISO15693_CMD_SELECT 0x25
#define ISO15693_CMD_RESET_TO_READY 0x26
#define ISO15693_CMD_WRITE_AFI 0x27
#define ISO15693_CMD_LOCK_AFI 0x28
#define ISO15693_CMD_WRITE_DSFID 0x29
#define ISO15693_CMD_LOCK_DSFID 0x2a
#define ISO15693_CMD_GET_SYSTEM_INFO 0x2b
#define ISO15693_CMD_GET_MULTIPLE_BLOCK_SECURITY_STATUS 0x2c
/* ISO 15693 request and response flags */
#define ISO15693_REQ_FLAG_SUB_CARRIER BIT(0)
#define ISO15693_REQ_FLAG_DATA_RATE BIT(1)
#define ISO15693_REQ_FLAG_INVENTORY BIT(2)
#define ISO15693_REQ_FLAG_PROTOCOL_EXT BIT(3)
#define ISO15693_REQ_FLAG_SELECT BIT(4)
#define ISO15693_REQ_FLAG_AFI BIT(4)
#define ISO15693_REQ_FLAG_ADDRESS BIT(5)
#define ISO15693_REQ_FLAG_NB_SLOTS BIT(5)
#define ISO15693_REQ_FLAG_OPTION BIT(6)
#define ISO15693_REQ_FLAG_SPEED_MASK \
(ISO15693_REQ_FLAG_SUB_CARRIER | ISO15693_REQ_FLAG_DATA_RATE)
enum trf7970a_state {
TRF7970A_ST_PWR_OFF,
TRF7970A_ST_RF_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_WAIT_TO_ISSUE_EOF,
TRF7970A_ST_LISTENING,
TRF7970A_ST_LISTENING_MD,
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 is_initiator;
bool aborting;
struct sk_buff *tx_skb;
struct sk_buff *rx_skb;
nfc_digital_cmd_complete_t cb;
void *cb_arg;
u8 chip_status_ctrl;
u8 iso_ctrl;
u8 iso_ctrl_tech;
u8 modulator_sys_clk_ctrl;
u8 special_fcn_reg1;
unsigned int guard_time;
int technology;
int framing;
u8 md_rf_tech;
u8 tx_cmd;
bool issue_eof;
bool adjust_resp_len;
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;
struct spi_transfer t[2];
struct spi_message m;
int ret;
dev_dbg(trf->dev, "read_cont(0x%x, %zd)\n", addr, len);
spi_message_init(&m);
memset(&t, 0, sizeof(t));
t[0].tx_buf = &addr;
t[0].len = sizeof(addr);
spi_message_add_tail(&t[0], &m);
t[1].rx_buf = buf;
t[1].len = len;
spi_message_add_tail(&t[1], &m);
ret = spi_sync(trf->spi, &m);
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) {
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 int trf7970a_read_target_proto(struct trf7970a *trf, u8 *target_proto)
{
int ret;
u8 buf[2];
u8 addr;
addr = TRF79070A_NFC_TARGET_PROTOCOL | TRF7970A_CMD_BIT_RW |
TRF7970A_CMD_BIT_CONTINUOUS;
ret = spi_write_then_read(trf->spi, &addr, 1, buf, 2);
if (ret)
dev_err(trf->dev, "%s - target_proto: Read failed: %d\n",
__func__, ret);
else
*target_proto = buf[0];
return ret;
}
static int trf7970a_mode_detect(struct trf7970a *trf, u8 *rf_tech)
{
int ret;
u8 target_proto, tech;
ret = trf7970a_read_target_proto(trf, &target_proto);
if (ret)
return ret;
switch (target_proto) {
case TRF79070A_NFC_TARGET_PROTOCOL_106A:
tech = NFC_DIGITAL_RF_TECH_106A;
break;
case TRF79070A_NFC_TARGET_PROTOCOL_106B:
tech = NFC_DIGITAL_RF_TECH_106B;
break;
case TRF79070A_NFC_TARGET_PROTOCOL_212F:
tech = NFC_DIGITAL_RF_TECH_212F;
break;
case TRF79070A_NFC_TARGET_PROTOCOL_424F:
tech = NFC_DIGITAL_RF_TECH_424F;
break;
default:
dev_dbg(trf->dev, "%s - mode_detect: target_proto: 0x%x\n",
__func__, target_proto);
return -EIO;
}
*rf_tech = tech;
return ret;
}
static void trf7970a_send_upstream(struct trf7970a *trf)
{
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);
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;
}
if (trf->adjust_resp_len) {
if (trf->rx_skb)
skb_trim(trf->rx_skb, trf->rx_skb->len - 1);
trf->adjust_resp_len = 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);
cancel_delayed_work(&trf->timeout_work);
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, u8 *prefix, unsigned int prefix_len)
{
struct spi_transfer t[2];
struct spi_message m;
unsigned int timeout;
int ret;
print_hex_dump_debug("trf7970a tx data: ", DUMP_PREFIX_NONE,
16, 1, skb->data, len, false);
spi_message_init(&m);
memset(&t, 0, sizeof(t));
t[0].tx_buf = prefix;
t[0].len = prefix_len;
spi_message_add_tail(&t[0], &m);
t[1].tx_buf = skb->data;
t[1].len = len;
spi_message_add_tail(&t[1], &m);
ret = spi_sync(trf->spi, &m);
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 {
if (trf->issue_eof) {
trf->state = TRF7970A_ST_WAIT_TO_ISSUE_EOF;
timeout = TRF7970A_WAIT_TO_ISSUE_ISO15693_EOF;
} else {
trf->state = TRF7970A_ST_WAIT_FOR_RX_DATA;
if (!trf->timeout)
timeout = TRF7970A_WAIT_FOR_TX_IRQ;
else
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;
u8 prefix;
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);
fifo_bytes &= ~TRF7970A_FIFO_STATUS_OVERFLOW;
/* Calculate how much more data can be written to the fifo */
len = TRF7970A_FIFO_SIZE - fifo_bytes;
if (!len) {
schedule_delayed_work(&trf->timeout_work,
msecs_to_jiffies(TRF7970A_WAIT_FOR_FIFO_DRAIN_TIMEOUT));
return;
}
len = min(skb->len, len);
prefix = TRF7970A_CMD_BIT_CONTINUOUS | TRF7970A_FIFO_IO_REGISTER;
ret = trf7970a_transmit(trf, skb, len, &prefix, sizeof(prefix));
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);
fifo_bytes &= ~TRF7970A_FIFO_STATUS_OVERFLOW;
if (!fifo_bytes)
goto no_rx_data;
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;
ret = trf7970a_read(trf, TRF7970A_FIFO_STATUS, &fifo_bytes);
if (ret) {
trf7970a_send_err_upstream(trf, ret);
return;
}
fifo_bytes &= ~TRF7970A_FIFO_STATUS_OVERFLOW;
/* If there are bytes in the FIFO, set status to '0' so
* the if stmt below doesn't fire and the driver will wait
* for the trf7970a to generate another RX interrupt.
*/
if (fifo_bytes)
status = 0;
}
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, fifo_bytes, iso_ctrl;
mutex_lock(&trf->lock);
if (trf->state == TRF7970A_ST_RF_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 initiator and getting interrupts caused by RF noise,
* turn off the receiver to avoid unnecessary interrupts.
* It will be turned back on in trf7970a_send_cmd() when
* the next command is issued.
*/
if (trf->is_initiator && (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_FIFO) {
ret = trf7970a_read(trf, TRF7970A_FIFO_STATUS,
&fifo_bytes);
fifo_bytes &= ~TRF7970A_FIFO_STATUS_OVERFLOW;
if (ret)
trf7970a_send_err_upstream(trf, ret);
else if (!fifo_bytes)
trf7970a_cmd(trf, TRF7970A_CMD_FIFO_RESET);
} else if ((status == TRF7970A_IRQ_STATUS_TX) ||
(!trf->is_initiator &&
(status == (TRF7970A_IRQ_STATUS_TX |
TRF7970A_IRQ_STATUS_NFC_RF)))) {
trf7970a_cmd(trf, TRF7970A_CMD_FIFO_RESET);
if (!trf->timeout) {
trf->ignore_timeout = !cancel_delayed_work(
&trf->timeout_work);
trf->rx_skb = ERR_PTR(0);
trf7970a_send_upstream(trf);
break;
}
if (trf->is_initiator)
break;
iso_ctrl = trf->iso_ctrl;
switch (trf->framing) {
case NFC_DIGITAL_FRAMING_NFCA_STANDARD:
trf->tx_cmd = TRF7970A_CMD_TRANSMIT_NO_CRC;
iso_ctrl |= TRF7970A_ISO_CTRL_RX_CRC_N;
trf->iso_ctrl = 0xff; /* Force ISO_CTRL write */
break;
case NFC_DIGITAL_FRAMING_NFCA_STANDARD_WITH_CRC_A:
trf->tx_cmd = TRF7970A_CMD_TRANSMIT;
iso_ctrl &= ~TRF7970A_ISO_CTRL_RX_CRC_N;
trf->iso_ctrl = 0xff; /* Force ISO_CTRL write */
break;
case NFC_DIGITAL_FRAMING_NFCA_ANTICOL_COMPLETE:
ret = trf7970a_write(trf,
TRF7970A_SPECIAL_FCN_REG1,
TRF7970A_SPECIAL_FCN_REG1_14_ANTICOLL);
if (ret)
goto err_unlock_exit;
trf->special_fcn_reg1 =
TRF7970A_SPECIAL_FCN_REG1_14_ANTICOLL;
break;
default:
break;
}
if (iso_ctrl != trf->iso_ctrl) {
ret = trf7970a_write(trf, TRF7970A_ISO_CTRL,
iso_ctrl);
if (ret)
goto err_unlock_exit;
trf->iso_ctrl = iso_ctrl;
}
} else {
trf7970a_send_err_upstream(trf, -EIO);
}
break;
case TRF7970A_ST_WAIT_TO_ISSUE_EOF:
if (status != TRF7970A_IRQ_STATUS_TX)
trf7970a_send_err_upstream(trf, -EIO);
break;
case TRF7970A_ST_LISTENING:
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_NFC_RF)) {
trf7970a_send_err_upstream(trf, -EIO);
}
break;
case TRF7970A_ST_LISTENING_MD:
if (status & TRF7970A_IRQ_STATUS_SRX) {
trf->ignore_timeout =
!cancel_delayed_work(&trf->timeout_work);
ret = trf7970a_mode_detect(trf, &trf->md_rf_tech);
if (ret) {
trf7970a_send_err_upstream(trf, ret);
} else {
trf->state = TRF7970A_ST_LISTENING;
trf7970a_drain_fifo(trf, status);
}
} else if (!(status & TRF7970A_IRQ_STATUS_NFC_RF)) {
trf7970a_send_err_upstream(trf, -EIO);
}
break;
default:
dev_err(trf->dev, "%s - Driver in invalid state: %d\n",
__func__, trf->state);
}
err_unlock_exit:
mutex_unlock(&trf->lock);
return IRQ_HANDLED;
}
static void trf7970a_issue_eof(struct trf7970a *trf)
{
int ret;
dev_dbg(trf->dev, "Issuing EOF\n");
ret = trf7970a_cmd(trf, TRF7970A_CMD_FIFO_RESET);
if (ret)
trf7970a_send_err_upstream(trf, ret);