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8006289108
linux/drivers/nfc/trf7970a.c
Mark A. Greer 8006289108 NFC: trf7970a: Add support for Type 4A Tags 
Add support for Type 4A Tags which includes
supporting the underlying ISO/IEC 14443-A
protocol.

Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-03-11 00:47:08 +01:00

1227 lines
33 KiB
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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/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 | NFC_PROTO_ISO14443_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:
case NFC_DIGITAL_FRAMING_NFCA_T4T:
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");
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