diff options
Diffstat (limited to 'drivers/nfc/st95hf/core.c')
| -rw-r--r-- | drivers/nfc/st95hf/core.c | 1273 |
1 files changed, 1273 insertions, 0 deletions
diff --git a/drivers/nfc/st95hf/core.c b/drivers/nfc/st95hf/core.c new file mode 100644 index 0000000..c2840e4 --- /dev/null +++ b/drivers/nfc/st95hf/core.c @@ -0,0 +1,1273 @@ +/* + * -------------------------------------------------------------------- + * Driver for ST NFC Transceiver ST95HF + * -------------------------------------------------------------------- + * Copyright (C) 2015 STMicroelectronics Pvt. Ltd. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/err.h> +#include <linux/gpio.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/module.h> +#include <linux/netdevice.h> +#include <linux/nfc.h> +#include <linux/of_gpio.h> +#include <linux/of.h> +#include <linux/of_irq.h> +#include <linux/property.h> +#include <linux/regulator/consumer.h> +#include <linux/wait.h> +#include <net/nfc/digital.h> +#include <net/nfc/nfc.h> + +#include "spi.h" + +/* supported protocols */ +#define ST95HF_SUPPORTED_PROT (NFC_PROTO_ISO14443_MASK | \ + NFC_PROTO_ISO14443_B_MASK | \ + NFC_PROTO_ISO15693_MASK) +/* driver capabilities */ +#define ST95HF_CAPABILITIES NFC_DIGITAL_DRV_CAPS_IN_CRC + +/* Command Send Interface */ +/* ST95HF_COMMAND_SEND CMD Ids */ +#define ECHO_CMD 0x55 +#define WRITE_REGISTER_CMD 0x9 +#define PROTOCOL_SELECT_CMD 0x2 +#define SEND_RECEIVE_CMD 0x4 + +/* Select protocol codes */ +#define ISO15693_PROTOCOL_CODE 0x1 +#define ISO14443A_PROTOCOL_CODE 0x2 +#define ISO14443B_PROTOCOL_CODE 0x3 + +/* + * head room len is 3 + * 1 byte for control byte + * 1 byte for cmd + * 1 byte for size + */ +#define ST95HF_HEADROOM_LEN 3 + +/* + * tailroom is 1 for ISO14443A + * and 0 for ISO14443B/ISO15693, + * hence the max value 1 should be + * taken. + */ +#define ST95HF_TAILROOM_LEN 1 + +/* Command Response interface */ +#define MAX_RESPONSE_BUFFER_SIZE 280 +#define ECHORESPONSE 0x55 +#define ST95HF_ERR_MASK 0xF +#define ST95HF_TIMEOUT_ERROR 0x87 +#define ST95HF_NFCA_CRC_ERR_MASK 0x20 +#define ST95HF_NFCB_CRC_ERR_MASK 0x01 + +/* ST95HF transmission flag values */ +#define TRFLAG_NFCA_SHORT_FRAME 0x07 +#define TRFLAG_NFCA_STD_FRAME 0x08 +#define TRFLAG_NFCA_STD_FRAME_CRC 0x28 + +/* Misc defs */ +#define HIGH 1 +#define LOW 0 +#define ISO14443A_RATS_REQ 0xE0 +#define RATS_TB1_PRESENT_MASK 0x20 +#define RATS_TA1_PRESENT_MASK 0x10 +#define TB1_FWI_MASK 0xF0 +#define WTX_REQ_FROM_TAG 0xF2 + +#define MAX_CMD_LEN 0x7 + +#define MAX_CMD_PARAMS 4 +struct cmd { + int cmd_len; + unsigned char cmd_id; + unsigned char no_cmd_params; + unsigned char cmd_params[MAX_CMD_PARAMS]; + enum req_type req; +}; + +struct param_list { + int param_offset; + int new_param_val; +}; + +/* + * List of top-level cmds to be used internally by the driver. + * All these commands are build on top of ST95HF basic commands + * such as SEND_RECEIVE_CMD, PROTOCOL_SELECT_CMD, etc. + * These top level cmds are used internally while implementing various ops of + * digital layer/driver probe or extending the digital framework layer for + * features that are not yet implemented there, for example, WTX cmd handling. + */ +enum st95hf_cmd_list { + CMD_ECHO, + CMD_ISO14443A_CONFIG, + CMD_ISO14443A_DEMOGAIN, + CMD_ISO14443B_DEMOGAIN, + CMD_ISO14443A_PROTOCOL_SELECT, + CMD_ISO14443B_PROTOCOL_SELECT, + CMD_WTX_RESPONSE, + CMD_FIELD_OFF, + CMD_ISO15693_PROTOCOL_SELECT, +}; + +static const struct cmd cmd_array[] = { + [CMD_ECHO] = { + .cmd_len = 0x2, + .cmd_id = ECHO_CMD, + .no_cmd_params = 0, + .req = SYNC, + }, + [CMD_ISO14443A_CONFIG] = { + .cmd_len = 0x7, + .cmd_id = WRITE_REGISTER_CMD, + .no_cmd_params = 0x4, + .cmd_params = {0x3A, 0x00, 0x5A, 0x04}, + .req = SYNC, + }, + [CMD_ISO14443A_DEMOGAIN] = { + .cmd_len = 0x7, + .cmd_id = WRITE_REGISTER_CMD, + .no_cmd_params = 0x4, + .cmd_params = {0x68, 0x01, 0x01, 0xDF}, + .req = SYNC, + }, + [CMD_ISO14443B_DEMOGAIN] = { + .cmd_len = 0x7, + .cmd_id = WRITE_REGISTER_CMD, + .no_cmd_params = 0x4, + .cmd_params = {0x68, 0x01, 0x01, 0x51}, + .req = SYNC, + }, + [CMD_ISO14443A_PROTOCOL_SELECT] = { + .cmd_len = 0x7, + .cmd_id = PROTOCOL_SELECT_CMD, + .no_cmd_params = 0x4, + .cmd_params = {ISO14443A_PROTOCOL_CODE, 0x00, 0x01, 0xA0}, + .req = SYNC, + }, + [CMD_ISO14443B_PROTOCOL_SELECT] = { + .cmd_len = 0x7, + .cmd_id = PROTOCOL_SELECT_CMD, + .no_cmd_params = 0x4, + .cmd_params = {ISO14443B_PROTOCOL_CODE, 0x01, 0x03, 0xFF}, + .req = SYNC, + }, + [CMD_WTX_RESPONSE] = { + .cmd_len = 0x6, + .cmd_id = SEND_RECEIVE_CMD, + .no_cmd_params = 0x3, + .cmd_params = {0xF2, 0x00, TRFLAG_NFCA_STD_FRAME_CRC}, + .req = ASYNC, + }, + [CMD_FIELD_OFF] = { + .cmd_len = 0x5, + .cmd_id = PROTOCOL_SELECT_CMD, + .no_cmd_params = 0x2, + .cmd_params = {0x0, 0x0}, + .req = SYNC, + }, + [CMD_ISO15693_PROTOCOL_SELECT] = { + .cmd_len = 0x5, + .cmd_id = PROTOCOL_SELECT_CMD, + .no_cmd_params = 0x2, + .cmd_params = {ISO15693_PROTOCOL_CODE, 0x0D}, + .req = SYNC, + }, +}; + +/* st95_digital_cmd_complete_arg stores client context */ +struct st95_digital_cmd_complete_arg { + struct sk_buff *skb_resp; + nfc_digital_cmd_complete_t complete_cb; + void *cb_usrarg; + bool rats; +}; + +/* + * structure containing ST95HF driver specific data. + * @spicontext: structure containing information required + * for spi communication between st95hf and host. + * @ddev: nfc digital device object. + * @nfcdev: nfc device object. + * @enable_gpio: gpio used to enable st95hf transceiver. + * @complete_cb_arg: structure to store various context information + * that is passed from nfc requesting thread to the threaded ISR. + * @st95hf_supply: regulator "consumer" for NFC device. + * @sendrcv_trflag: last byte of frame send by sendrecv command + * of st95hf. This byte contains transmission flag info. + * @exchange_lock: semaphore used for signaling the st95hf_remove + * function that the last outstanding async nfc request is finished. + * @rm_lock: mutex for ensuring safe access of nfc digital object + * from threaded ISR. Usage of this mutex avoids any race between + * deletion of the object from st95hf_remove() and its access from + * the threaded ISR. + * @nfcdev_free: flag to have the state of nfc device object. + * [alive | died] + * @current_protocol: current nfc protocol. + * @current_rf_tech: current rf technology. + * @fwi: frame waiting index, received in reply of RATS according to + * digital protocol. + */ +struct st95hf_context { + struct st95hf_spi_context spicontext; + struct nfc_digital_dev *ddev; + struct nfc_dev *nfcdev; + unsigned int enable_gpio; + struct st95_digital_cmd_complete_arg complete_cb_arg; + struct regulator *st95hf_supply; + unsigned char sendrcv_trflag; + struct semaphore exchange_lock; + struct mutex rm_lock; + bool nfcdev_free; + u8 current_protocol; + u8 current_rf_tech; + int fwi; +}; + +/* + * st95hf_send_recv_cmd() is for sending commands to ST95HF + * that are described in the cmd_array[]. It can optionally + * receive the response if the cmd request is of type + * SYNC. For that to happen caller must pass true to recv_res. + * For ASYNC request, recv_res is ignored and the + * function will never try to receive the response on behalf + * of the caller. + */ +static int st95hf_send_recv_cmd(struct st95hf_context *st95context, + enum st95hf_cmd_list cmd, + int no_modif, + struct param_list *list_array, + bool recv_res) +{ + unsigned char spi_cmd_buffer[MAX_CMD_LEN]; + int i, ret; + struct device *dev = &st95context->spicontext.spidev->dev; + + if (cmd_array[cmd].cmd_len > MAX_CMD_LEN) + return -EINVAL; + if (cmd_array[cmd].no_cmd_params < no_modif) + return -EINVAL; + if (no_modif && !list_array) + return -EINVAL; + + spi_cmd_buffer[0] = ST95HF_COMMAND_SEND; + spi_cmd_buffer[1] = cmd_array[cmd].cmd_id; + spi_cmd_buffer[2] = cmd_array[cmd].no_cmd_params; + + memcpy(&spi_cmd_buffer[3], cmd_array[cmd].cmd_params, + spi_cmd_buffer[2]); + + for (i = 0; i < no_modif; i++) { + if (list_array[i].param_offset >= cmd_array[cmd].no_cmd_params) + return -EINVAL; + spi_cmd_buffer[3 + list_array[i].param_offset] = + list_array[i].new_param_val; + } + + ret = st95hf_spi_send(&st95context->spicontext, + spi_cmd_buffer, + cmd_array[cmd].cmd_len, + cmd_array[cmd].req); + if (ret) { + dev_err(dev, "st95hf_spi_send failed with error %d\n", ret); + return ret; + } + + if (cmd_array[cmd].req == SYNC && recv_res) { + unsigned char st95hf_response_arr[2]; + + ret = st95hf_spi_recv_response(&st95context->spicontext, + st95hf_response_arr); + if (ret < 0) { + dev_err(dev, "spi error from st95hf_spi_recv_response(), err = 0x%x\n", + ret); + return ret; + } + + if (st95hf_response_arr[0]) { + dev_err(dev, "st95hf error from st95hf_spi_recv_response(), err = 0x%x\n", + st95hf_response_arr[0]); + return -EIO; + } + } + + return 0; +} + +static int st95hf_echo_command(struct st95hf_context *st95context) +{ + int result = 0; + unsigned char echo_response; + + result = st95hf_send_recv_cmd(st95context, CMD_ECHO, 0, NULL, false); + if (result) + return result; + + /* If control reached here, response can be taken */ + result = st95hf_spi_recv_echo_res(&st95context->spicontext, + &echo_response); + if (result) { + dev_err(&st95context->spicontext.spidev->dev, + "err: echo response receieve error = 0x%x\n", result); + return result; + } + + if (echo_response == ECHORESPONSE) + return 0; + + dev_err(&st95context->spicontext.spidev->dev, "err: echo res is 0x%x\n", + echo_response); + + return -EIO; +} + +static int secondary_configuration_type4a(struct st95hf_context *stcontext) +{ + int result = 0; + struct device *dev = &stcontext->nfcdev->dev; + + /* 14443A config setting after select protocol */ + result = st95hf_send_recv_cmd(stcontext, + CMD_ISO14443A_CONFIG, + 0, + NULL, + true); + if (result) { + dev_err(dev, "type a config cmd, err = 0x%x\n", result); + return result; + } + + /* 14443A demo gain setting */ + result = st95hf_send_recv_cmd(stcontext, + CMD_ISO14443A_DEMOGAIN, + 0, + NULL, + true); + if (result) + dev_err(dev, "type a demogain cmd, err = 0x%x\n", result); + + return result; +} + +static int secondary_configuration_type4b(struct st95hf_context *stcontext) +{ + int result = 0; + struct device *dev = &stcontext->nfcdev->dev; + + result = st95hf_send_recv_cmd(stcontext, + CMD_ISO14443B_DEMOGAIN, + 0, + NULL, + true); + if (result) + dev_err(dev, "type b demogain cmd, err = 0x%x\n", result); + + return result; +} + +static int st95hf_select_protocol(struct st95hf_context *stcontext, int type) +{ + int result = 0; + struct device *dev; + + dev = &stcontext->nfcdev->dev; + + switch (type) { + case NFC_DIGITAL_RF_TECH_106A: + stcontext->current_rf_tech = NFC_DIGITAL_RF_TECH_106A; + result = st95hf_send_recv_cmd(stcontext, + CMD_ISO14443A_PROTOCOL_SELECT, + 0, + NULL, + true); + if (result) { + dev_err(dev, "protocol sel, err = 0x%x\n", + result); + return result; + } + + /* secondary config. for 14443Type 4A after protocol select */ + result = secondary_configuration_type4a(stcontext); + if (result) { + dev_err(dev, "type a secondary config, err = 0x%x\n", + result); + return result; + } + break; + case NFC_DIGITAL_RF_TECH_106B: + stcontext->current_rf_tech = NFC_DIGITAL_RF_TECH_106B; + result = st95hf_send_recv_cmd(stcontext, + CMD_ISO14443B_PROTOCOL_SELECT, + 0, + NULL, + true); + if (result) { + dev_err(dev, "protocol sel send, err = 0x%x\n", + result); + return result; + } + + /* + * delay of 5-6 ms is required after select protocol + * command in case of ISO14443 Type B + */ + usleep_range(50000, 60000); + + /* secondary config. for 14443Type 4B after protocol select */ + result = secondary_configuration_type4b(stcontext); + if (result) { + dev_err(dev, "type b secondary config, err = 0x%x\n", + result); + return result; + } + break; + case NFC_DIGITAL_RF_TECH_ISO15693: + stcontext->current_rf_tech = NFC_DIGITAL_RF_TECH_ISO15693; + result = st95hf_send_recv_cmd(stcontext, + CMD_ISO15693_PROTOCOL_SELECT, + 0, + NULL, + true); + if (result) { + dev_err(dev, "protocol sel send, err = 0x%x\n", + result); + return result; + } + break; + default: + return -EINVAL; + } + + return 0; +} + +static void st95hf_send_st95enable_negativepulse(struct st95hf_context *st95con) +{ + /* First make irq_in pin high */ + gpio_set_value(st95con->enable_gpio, HIGH); + + /* wait for 1 milisecond */ + usleep_range(1000, 2000); + + /* Make irq_in pin low */ + gpio_set_value(st95con->enable_gpio, LOW); + + /* wait for minimum interrupt pulse to make st95 active */ + usleep_range(1000, 2000); + + /* At end make it high */ + gpio_set_value(st95con->enable_gpio, HIGH); +} + +/* + * Send a reset sequence over SPI bus (Reset command + wait 3ms + + * negative pulse on st95hf enable gpio + */ +static int st95hf_send_spi_reset_sequence(struct st95hf_context *st95context) +{ + int result = 0; + unsigned char reset_cmd = ST95HF_COMMAND_RESET; + + result = st95hf_spi_send(&st95context->spicontext, + &reset_cmd, + ST95HF_RESET_CMD_LEN, + ASYNC); + if (result) { + dev_err(&st95context->spicontext.spidev->dev, + "spi reset sequence cmd error = %d", result); + return result; + } + + /* wait for 3 milisecond to complete the controller reset process */ + usleep_range(3000, 4000); + + /* send negative pulse to make st95hf active */ + st95hf_send_st95enable_negativepulse(st95context); + + /* wait for 10 milisecond : HFO setup time */ + usleep_range(10000, 20000); + + return result; +} + +static int st95hf_por_sequence(struct st95hf_context *st95context) +{ + int nth_attempt = 1; + int result; + + st95hf_send_st95enable_negativepulse(st95context); + + usleep_range(5000, 6000); + do { + /* send an ECHO command and checks ST95HF response */ + result = st95hf_echo_command(st95context); + + dev_dbg(&st95context->spicontext.spidev->dev, + "response from echo function = 0x%x, attempt = %d\n", + result, nth_attempt); + + if (!result) + return 0; + + /* send an pulse on IRQ in case of the chip is on sleep state */ + if (nth_attempt == 2) + st95hf_send_st95enable_negativepulse(st95context); + else + st95hf_send_spi_reset_sequence(st95context); + + /* delay of 50 milisecond */ + usleep_range(50000, 51000); + } while (nth_attempt++ < 3); + + return -ETIMEDOUT; +} + +static int iso14443_config_fdt(struct st95hf_context *st95context, int wtxm) +{ + int result = 0; + struct device *dev = &st95context->spicontext.spidev->dev; + struct nfc_digital_dev *nfcddev = st95context->ddev; + unsigned char pp_typeb; + struct param_list new_params[2]; + + pp_typeb = cmd_array[CMD_ISO14443B_PROTOCOL_SELECT].cmd_params[2]; + + if (nfcddev->curr_protocol == NFC_PROTO_ISO14443 && + st95context->fwi < 4) + st95context->fwi = 4; + + new_params[0].param_offset = 2; + if (nfcddev->curr_protocol == NFC_PROTO_ISO14443) + new_params[0].new_param_val = st95context->fwi; + else if (nfcddev->curr_protocol == NFC_PROTO_ISO14443_B) + new_params[0].new_param_val = pp_typeb; + + new_params[1].param_offset = 3; + new_params[1].new_param_val = wtxm; + + switch (nfcddev->curr_protocol) { + case NFC_PROTO_ISO14443: + result = st95hf_send_recv_cmd(st95context, + CMD_ISO14443A_PROTOCOL_SELECT, + 2, + new_params, + true); + if (result) { + dev_err(dev, "WTX type a sel proto, err = 0x%x\n", + result); + return result; + } + + /* secondary config. for 14443Type 4A after protocol select */ + result = secondary_configuration_type4a(st95context); + if (result) { + dev_err(dev, "WTX type a second. config, err = 0x%x\n", + result); + return result; + } + break; + case NFC_PROTO_ISO14443_B: + result = st95hf_send_recv_cmd(st95context, + CMD_ISO14443B_PROTOCOL_SELECT, + 2, + new_params, + true); + if (result) { + dev_err(dev, "WTX type b sel proto, err = 0x%x\n", + result); + return result; + } + + /* secondary config. for 14443Type 4B after protocol select */ + result = secondary_configuration_type4b(st95context); + if (result) { + dev_err(dev, "WTX type b second. config, err = 0x%x\n", + result); + return result; + } + break; + default: + return -EINVAL; + } + + return 0; +} + +static int st95hf_handle_wtx(struct st95hf_context *stcontext, + bool new_wtx, + int wtx_val) +{ + int result = 0; + unsigned char val_mm = 0; + struct param_list new_params[1]; + struct nfc_digital_dev *nfcddev = stcontext->ddev; + struct device *dev = &stcontext->nfcdev->dev; + + if (new_wtx) { + result = iso14443_config_fdt(stcontext, wtx_val & 0x3f); + if (result) { + dev_err(dev, "Config. setting error on WTX req, err = 0x%x\n", + result); + return result; + } + + /* Send response of wtx with ASYNC as no response expected */ + new_params[0].param_offset = 1; + new_params[0].new_param_val = wtx_val; + + result = st95hf_send_recv_cmd(stcontext, + CMD_WTX_RESPONSE, + 1, + new_params, + false); + if (result) + dev_err(dev, "WTX response send, err = 0x%x\n", result); + return result; + } + + /* if no new wtx, cofigure with default values */ + if (nfcddev->curr_protocol == NFC_PROTO_ISO14443) + val_mm = cmd_array[CMD_ISO14443A_PROTOCOL_SELECT].cmd_params[3]; + else if (nfcddev->curr_protocol == NFC_PROTO_ISO14443_B) + val_mm = cmd_array[CMD_ISO14443B_PROTOCOL_SELECT].cmd_params[3]; + + result = iso14443_config_fdt(stcontext, val_mm); + if (result) + dev_err(dev, "Default config. setting error after WTX processing, err = 0x%x\n", + result); + + return result; +} + +static int st95hf_error_handling(struct st95hf_context *stcontext, + struct sk_buff *skb_resp, + int res_len) +{ + int result = 0; + unsigned char error_byte; + struct device *dev = &stcontext->nfcdev->dev; + + /* First check ST95HF specific error */ + if (skb_resp->data[0] & ST95HF_ERR_MASK) { + if (skb_resp->data[0] == ST95HF_TIMEOUT_ERROR) + result = -ETIMEDOUT; + else + result = -EIO; + return result; + } + + /* Check for CRC err only if CRC is present in the tag response */ + switch (stcontext->current_rf_tech) { + case NFC_DIGITAL_RF_TECH_106A: + if (stcontext->sendrcv_trflag == TRFLAG_NFCA_STD_FRAME_CRC) { + error_byte = skb_resp->data[res_len - 3]; + if (error_byte & ST95HF_NFCA_CRC_ERR_MASK) { + /* CRC error occurred */ + dev_err(dev, "CRC error, byte received = 0x%x\n", + error_byte); + result = -EIO; + } + } + break; + case NFC_DIGITAL_RF_TECH_106B: + case NFC_DIGITAL_RF_TECH_ISO15693: + error_byte = skb_resp->data[res_len - 1]; + if (error_byte & ST95HF_NFCB_CRC_ERR_MASK) { + /* CRC error occurred */ + dev_err(dev, "CRC error, byte received = 0x%x\n", + error_byte); + result = -EIO; + } + break; + } + + return result; +} + +static int st95hf_response_handler(struct st95hf_context *stcontext, + struct sk_buff *skb_resp, + int res_len) +{ + int result = 0; + int skb_len; + unsigned char val_mm; + struct nfc_digital_dev *nfcddev = stcontext->ddev; + struct device *dev = &stcontext->nfcdev->dev; + struct st95_digital_cmd_complete_arg *cb_arg; + + cb_arg = &stcontext->complete_cb_arg; + + /* Process the response */ + skb_put(skb_resp, res_len); + + /* Remove st95 header */ + skb_pull(skb_resp, 2); + + skb_len = skb_resp->len; + + /* check if it is case of RATS request reply & FWI is present */ + if (nfcddev->curr_protocol == NFC_PROTO_ISO14443 && cb_arg->rats && + (skb_resp->data[1] & RATS_TB1_PRESENT_MASK)) { + if (skb_resp->data[1] & RATS_TA1_PRESENT_MASK) + stcontext->fwi = + (skb_resp->data[3] & TB1_FWI_MASK) >> 4; + else + stcontext->fwi = + (skb_resp->data[2] & TB1_FWI_MASK) >> 4; + + val_mm = cmd_array[CMD_ISO14443A_PROTOCOL_SELECT].cmd_params[3]; + + result = iso14443_config_fdt(stcontext, val_mm); + if (result) { + dev_err(dev, "error in config_fdt to handle fwi of ATS, error=%d\n", + result); + return result; + } + } + cb_arg->rats = false; + + /* Remove CRC bytes only if received frames data has an eod (CRC) */ + switch (stcontext->current_rf_tech) { + case NFC_DIGITAL_RF_TECH_106A: + if (stcontext->sendrcv_trflag == TRFLAG_NFCA_STD_FRAME_CRC) + skb_trim(skb_resp, (skb_len - 5)); + else + skb_trim(skb_resp, (skb_len - 3)); + break; + case NFC_DIGITAL_RF_TECH_106B: + case NFC_DIGITAL_RF_TECH_ISO15693: + skb_trim(skb_resp, (skb_len - 3)); + break; + } + + return result; +} + +static irqreturn_t st95hf_irq_handler(int irq, void *st95hfcontext) +{ + struct st95hf_context *stcontext = + (struct st95hf_context *)st95hfcontext; + + if (stcontext->spicontext.req_issync) { + complete(&stcontext->spicontext.done); + stcontext->spicontext.req_issync = false; + return IRQ_HANDLED; + } + + return IRQ_WAKE_THREAD; +} + +static irqreturn_t st95hf_irq_thread_handler(int irq, void *st95hfcontext) +{ + int result = 0; + int res_len; + static bool wtx; + struct device *dev; + struct device *spidevice; + struct nfc_digital_dev *nfcddev; + struct sk_buff *skb_resp; + struct st95hf_context *stcontext = + (struct st95hf_context *)st95hfcontext; + struct st95_digital_cmd_complete_arg *cb_arg; + + spidevice = &stcontext->spicontext.spidev->dev; + + /* + * check semaphore, if not down() already, then we don't + * know in which context the ISR is called and surely it + * will be a bug. Note that down() of the semaphore is done + * in the corresponding st95hf_in_send_cmd() and then + * only this ISR should be called. ISR will up() the + * semaphore before leaving. Hence when the ISR is called + * the correct behaviour is down_trylock() should always + * return 1 (indicating semaphore cant be taken and hence no + * change in semaphore count). + * If not, then we up() the semaphore and crash on + * a BUG() ! + */ + if (!down_trylock(&stcontext->exchange_lock)) { + up(&stcontext->exchange_lock); + WARN(1, "unknown context in ST95HF ISR"); + return IRQ_NONE; + } + + cb_arg = &stcontext->complete_cb_arg; + skb_resp = cb_arg->skb_resp; + + mutex_lock(&stcontext->rm_lock); + res_len = st95hf_spi_recv_response(&stcontext->spicontext, + skb_resp->data); + if (res_len < 0) { + dev_err(spidevice, "TISR spi response err = 0x%x\n", res_len); + result = res_len; + goto end; + } + + /* if stcontext->nfcdev_free is true, it means remove already ran */ + if (stcontext->nfcdev_free) { + result = -ENODEV; + goto end; + } + + dev = &stcontext->nfcdev->dev; + nfcddev = stcontext->ddev; + if (skb_resp->data[2] == WTX_REQ_FROM_TAG) { + /* Request for new FWT from tag */ + result = st95hf_handle_wtx(stcontext, true, skb_resp->data[3]); + if (result) + goto end; + + wtx = true; + mutex_unlock(&stcontext->rm_lock); + return IRQ_HANDLED; + } + + result = st95hf_error_handling(stcontext, skb_resp, res_len); + if (result) + goto end; + + result = st95hf_response_handler(stcontext, skb_resp, res_len); + if (result) + goto end; + + /* + * If select protocol is done on wtx req. do select protocol + * again with default values + */ + if (wtx) { + wtx = false; + result = st95hf_handle_wtx(stcontext, false, 0); + if (result) + goto end; + } + + /* call digital layer callback */ + cb_arg->complete_cb(stcontext->ddev, cb_arg->cb_usrarg, skb_resp); + + /* up the semaphore before returning */ + up(&stcontext->exchange_lock); + mutex_unlock(&stcontext->rm_lock); + + return IRQ_HANDLED; + +end: + kfree_skb(skb_resp); + wtx = false; + cb_arg->rats = false; + skb_resp = ERR_PTR(result); + /* call of callback with error */ + cb_arg->complete_cb(stcontext->ddev, cb_arg->cb_usrarg, skb_resp); + /* up the semaphore before returning */ + up(&stcontext->exchange_lock); + mutex_unlock(&stcontext->rm_lock); + return IRQ_HANDLED; +} + +/* NFC ops functions definition */ +static int st95hf_in_configure_hw(struct nfc_digital_dev *ddev, + int type, + int param) +{ + struct st95hf_context *stcontext = nfc_digital_get_drvdata(ddev); + + if (type == NFC_DIGITAL_CONFIG_RF_TECH) + return st95hf_select_protocol(stcontext, param); + + if (type == NFC_DIGITAL_CONFIG_FRAMING) { + switch (param) { + case NFC_DIGITAL_FRAMING_NFCA_SHORT: + stcontext->sendrcv_trflag = TRFLAG_NFCA_SHORT_FRAME; + break; + case NFC_DIGITAL_FRAMING_NFCA_STANDARD: + stcontext->sendrcv_trflag = TRFLAG_NFCA_STD_FRAME; + break; + case NFC_DIGITAL_FRAMING_NFCA_T4T: + case NFC_DIGITAL_FRAMING_NFCA_NFC_DEP: + case NFC_DIGITAL_FRAMING_NFCA_STANDARD_WITH_CRC_A: + stcontext->sendrcv_trflag = TRFLAG_NFCA_STD_FRAME_CRC; + break; + case NFC_DIGITAL_FRAMING_NFCB: + case NFC_DIGITAL_FRAMING_ISO15693_INVENTORY: + case NFC_DIGITAL_FRAMING_ISO15693_T5T: + break; + } + } + + return 0; +} + +static int rf_off(struct st95hf_context *stcontext) +{ + int rc; + struct device *dev; + + dev = &stcontext->nfcdev->dev; + + rc = st95hf_send_recv_cmd(stcontext, CMD_FIELD_OFF, 0, NULL, true); + if (rc) + dev_err(dev, "protocol sel send field off, err = 0x%x\n", rc); + + return rc; +} + +static int st95hf_in_send_cmd(struct nfc_digital_dev *ddev, + struct sk_buff *skb, + u16 timeout, + nfc_digital_cmd_complete_t cb, + void *arg) +{ + struct st95hf_context *stcontext = nfc_digital_get_drvdata(ddev); + int rc; + struct sk_buff *skb_resp; + int len_data_to_tag = 0; + + skb_resp = nfc_alloc_recv_skb(MAX_RESPONSE_BUFFER_SIZE, GFP_KERNEL); + if (!skb_resp) { + rc = -ENOMEM; + goto error; + } + + switch (stcontext->current_rf_tech) { + case NFC_DIGITAL_RF_TECH_106A: + len_data_to_tag = skb->len + 1; + *skb_put(skb, 1) = stcontext->sendrcv_trflag; + break; + case NFC_DIGITAL_RF_TECH_106B: + case NFC_DIGITAL_RF_TECH_ISO15693: + len_data_to_tag = skb->len; + break; + default: + rc = -EINVAL; + goto free_skb_resp; + } + + skb_push(skb, 3); + skb->data[0] = ST95HF_COMMAND_SEND; + skb->data[1] = SEND_RECEIVE_CMD; + skb->data[2] = len_data_to_tag; + + stcontext->complete_cb_arg.skb_resp = skb_resp; + stcontext->complete_cb_arg.cb_usrarg = arg; + stcontext->complete_cb_arg.complete_cb = cb; + + if ((skb->data[3] == ISO14443A_RATS_REQ) && + ddev->curr_protocol == NFC_PROTO_ISO14443) + stcontext->complete_cb_arg.rats = true; + + /* + * down the semaphore to indicate to remove func that an + * ISR is pending, note that it will not block here in any case. + * If found blocked, it is a BUG! + */ + rc = down_killable(&stcontext->exchange_lock); + if (rc) { + WARN(1, "Semaphore is not found up in st95hf_in_send_cmd\n"); + return rc; + } + + rc = st95hf_spi_send(&stcontext->spicontext, skb->data, + skb->len, + ASYNC); + if (rc) { + dev_err(&stcontext->nfcdev->dev, + "Error %d trying to perform data_exchange", rc); + /* up the semaphore since ISR will never come in this case */ + up(&stcontext->exchange_lock); + goto free_skb_resp; + } + + kfree_skb(skb); + + return rc; + +free_skb_resp: + kfree_skb(skb_resp); +error: + return rc; +} + +/* p2p will be supported in a later release ! */ +static int st95hf_tg_configure_hw(struct nfc_digital_dev *ddev, + int type, + int param) +{ + return 0; +} + +static int st95hf_tg_send_cmd(struct nfc_digital_dev *ddev, + struct sk_buff *skb, + u16 timeout, + nfc_digital_cmd_complete_t cb, + void *arg) +{ + return 0; +} + +static int st95hf_tg_listen(struct nfc_digital_dev *ddev, + u16 timeout, + nfc_digital_cmd_complete_t cb, + void *arg) +{ + return 0; +} + +static int st95hf_tg_get_rf_tech(struct nfc_digital_dev *ddev, u8 *rf_tech) +{ + return 0; +} + +static int st95hf_switch_rf(struct nfc_digital_dev *ddev, bool on) +{ + u8 rf_tech; + struct st95hf_context *stcontext = nfc_digital_get_drvdata(ddev); + + rf_tech = ddev->curr_rf_tech; + + if (on) + /* switch on RF field */ + return st95hf_select_protocol(stcontext, rf_tech); + + /* switch OFF RF field */ + return rf_off(stcontext); +} + +/* TODO st95hf_abort_cmd */ +static void st95hf_abort_cmd(struct nfc_digital_dev *ddev) +{ +} + +static struct nfc_digital_ops st95hf_nfc_digital_ops = { + .in_configure_hw = st95hf_in_configure_hw, + .in_send_cmd = st95hf_in_send_cmd, + + .tg_listen = st95hf_tg_listen, + .tg_configure_hw = st95hf_tg_configure_hw, + .tg_send_cmd = st95hf_tg_send_cmd, + .tg_get_rf_tech = st95hf_tg_get_rf_tech, + + .switch_rf = st95hf_switch_rf, + .abort_cmd = st95hf_abort_cmd, +}; + +static const struct spi_device_id st95hf_id[] = { + { "st95hf", 0 }, + {} +}; +MODULE_DEVICE_TABLE(spi, st95hf_id); + +static int st95hf_probe(struct spi_device *nfc_spi_dev) +{ + int ret; + + struct st95hf_context *st95context; + struct st95hf_spi_context *spicontext; + + nfc_info(&nfc_spi_dev->dev, "ST95HF driver probe called.\n"); + + st95context = devm_kzalloc(&nfc_spi_dev->dev, + sizeof(struct st95hf_context), + GFP_KERNEL); + if (!st95context) + return -ENOMEM; + + spicontext = &st95context->spicontext; + + spicontext->spidev = nfc_spi_dev; + + st95context->fwi = + cmd_array[CMD_ISO14443A_PROTOCOL_SELECT].cmd_params[2]; + + if (device_property_present(&nfc_spi_dev->dev, "st95hfvin")) { + st95context->st95hf_supply = + devm_regulator_get(&nfc_spi_dev->dev, + "st95hfvin"); + if (IS_ERR(st95context->st95hf_supply)) { + dev_err(&nfc_spi_dev->dev, "failed to acquire regulator\n"); + return PTR_ERR(st95context->st95hf_supply); + } + + ret = regulator_enable(st95context->st95hf_supply); + if (ret) { + dev_err(&nfc_spi_dev->dev, "failed to enable regulator\n"); + return ret; + } + } + + init_completion(&spicontext->done); + mutex_init(&spicontext->spi_lock); + + /* + * Store spicontext in spi device object for using it in + * remove function + */ + dev_set_drvdata(&nfc_spi_dev->dev, spicontext); + + st95context->enable_gpio = + of_get_named_gpio(nfc_spi_dev->dev.of_node, + "enable-gpio", + 0); + if (!gpio_is_valid(st95context->enable_gpio)) { + dev_err(&nfc_spi_dev->dev, "No valid enable gpio\n"); + ret = st95context->enable_gpio; + goto err_disable_regulator; + } + + ret = devm_gpio_request_one(&nfc_spi_dev->dev, st95context->enable_gpio, + GPIOF_DIR_OUT | GPIOF_INIT_HIGH, + "enable_gpio"); + if (ret) + goto err_disable_regulator; + + if (nfc_spi_dev->irq > 0) { + if (devm_request_threaded_irq(&nfc_spi_dev->dev, + nfc_spi_dev->irq, + st95hf_irq_handler, + st95hf_irq_thread_handler, + IRQF_TRIGGER_FALLING, + "st95hf", + (void *)st95context) < 0) { + dev_err(&nfc_spi_dev->dev, "err: irq request for st95hf is failed\n"); + ret = -EINVAL; + goto err_disable_regulator; + } + } else { + dev_err(&nfc_spi_dev->dev, "not a valid IRQ associated with ST95HF\n"); + ret = -EINVAL; + goto err_disable_regulator; + } + + /* + * First reset SPI to handle warm reset of the system. + * It will put the ST95HF device in Power ON state + * which make the state of device identical to state + * at the time of cold reset of the system. + */ + ret = st95hf_send_spi_reset_sequence(st95context); + if (ret) { + dev_err(&nfc_spi_dev->dev, "err: spi_reset_sequence failed\n"); + goto err_disable_regulator; + } + + /* call PowerOnReset sequence of ST95hf to activate it */ + ret = st95hf_por_sequence(st95context); + if (ret) { + dev_err(&nfc_spi_dev->dev, "err: por seq failed for st95hf\n"); + goto err_disable_regulator; + } + + /* create NFC dev object and register with NFC Subsystem */ + st95context->ddev = nfc_digital_allocate_device(&st95hf_nfc_digital_ops, + ST95HF_SUPPORTED_PROT, + ST95HF_CAPABILITIES, + ST95HF_HEADROOM_LEN, + ST95HF_TAILROOM_LEN); + if (!st95context->ddev) { + ret = -ENOMEM; + goto err_disable_regulator; + } + + st95context->nfcdev = st95context->ddev->nfc_dev; + nfc_digital_set_parent_dev(st95context->ddev, &nfc_spi_dev->dev); + + ret = nfc_digital_register_device(st95context->ddev); + if (ret) { + dev_err(&st95context->nfcdev->dev, "st95hf registration failed\n"); + goto err_free_digital_device; + } + + /* store st95context in nfc device object */ + nfc_digital_set_drvdata(st95context->ddev, st95context); + + sema_init(&st95context->exchange_lock, 1); + mutex_init(&st95context->rm_lock); + + return ret; + +err_free_digital_device: + nfc_digital_free_device(st95context->ddev); +err_disable_regulator: + if (st95context->st95hf_supply) + regulator_disable(st95context->st95hf_supply); + + return ret; +} + +static int st95hf_remove(struct spi_device *nfc_spi_dev) +{ + int result = 0; + unsigned char reset_cmd = ST95HF_COMMAND_RESET; + struct st95hf_spi_context *spictx = dev_get_drvdata(&nfc_spi_dev->dev); + + struct st95hf_context *stcontext = container_of(spictx, + struct st95hf_context, + spicontext); + + mutex_lock(&stcontext->rm_lock); + + nfc_digital_unregister_device(stcontext->ddev); + nfc_digital_free_device(stcontext->ddev); + stcontext->nfcdev_free = true; + + mutex_unlock(&stcontext->rm_lock); + + /* if last in_send_cmd's ISR is pending, wait for it to finish */ + result = down_killable(&stcontext->exchange_lock); + if (result == -EINTR) + dev_err(&spictx->spidev->dev, "sleep for semaphore interrupted by signal\n"); + + /* next reset the ST95HF controller */ + result = st95hf_spi_send(&stcontext->spicontext, + &reset_cmd, + ST95HF_RESET_CMD_LEN, + ASYNC); + if (result) { + dev_err(&spictx->spidev->dev, + "ST95HF reset failed in remove() err = %d\n", result); + return result; + } + + /* wait for 3 ms to complete the controller reset process */ + usleep_range(3000, 4000); + + /* disable regulator */ + if (stcontext->st95hf_supply) + regulator_disable(stcontext->st95hf_supply); + + return result; +} + +/* Register as SPI protocol driver */ +static struct spi_driver st95hf_driver = { + .driver = { + .name = "st95hf", + .owner = THIS_MODULE, + }, + .id_table = st95hf_id, + .probe = st95hf_probe, + .remove = st95hf_remove, +}; + +module_spi_driver(st95hf_driver); + +MODULE_AUTHOR("Shikha Singh <shikha.singh@st.com>"); +MODULE_DESCRIPTION("ST NFC Transceiver ST95HF driver"); +MODULE_LICENSE("GPL v2"); |