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311 lines
7.4 KiB
311 lines
7.4 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Driver for the TAOS evaluation modules |
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* These devices include an I2C master which can be controlled over the |
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* serial port. |
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* |
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* Copyright (C) 2007 Jean Delvare <[email protected]> |
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*/ |
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#include <linux/delay.h> |
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#include <linux/module.h> |
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#include <linux/slab.h> |
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#include <linux/interrupt.h> |
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#include <linux/input.h> |
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#include <linux/serio.h> |
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#include <linux/init.h> |
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#include <linux/i2c.h> |
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#define TAOS_BUFFER_SIZE 63 |
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#define TAOS_STATE_INIT 0 |
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#define TAOS_STATE_IDLE 1 |
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#define TAOS_STATE_EOFF 2 |
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#define TAOS_STATE_RECV 3 |
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#define TAOS_CMD_RESET 0x12 |
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#define TAOS_CMD_ECHO_ON '+' |
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#define TAOS_CMD_ECHO_OFF '-' |
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static DECLARE_WAIT_QUEUE_HEAD(wq); |
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struct taos_data { |
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struct i2c_adapter adapter; |
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struct i2c_client *client; |
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int state; |
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u8 addr; /* last used address */ |
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unsigned char buffer[TAOS_BUFFER_SIZE]; |
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unsigned int pos; /* position inside the buffer */ |
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}; |
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/* TAOS TSL2550 EVM */ |
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static const struct i2c_board_info tsl2550_info = { |
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I2C_BOARD_INFO("tsl2550", 0x39), |
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}; |
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/* Instantiate i2c devices based on the adapter name */ |
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static struct i2c_client *taos_instantiate_device(struct i2c_adapter *adapter) |
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{ |
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if (!strncmp(adapter->name, "TAOS TSL2550 EVM", 16)) { |
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dev_info(&adapter->dev, "Instantiating device %s at 0x%02x\n", |
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tsl2550_info.type, tsl2550_info.addr); |
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return i2c_new_client_device(adapter, &tsl2550_info); |
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} |
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return ERR_PTR(-ENODEV); |
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} |
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static int taos_smbus_xfer(struct i2c_adapter *adapter, u16 addr, |
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unsigned short flags, char read_write, u8 command, |
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int size, union i2c_smbus_data *data) |
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{ |
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struct serio *serio = adapter->algo_data; |
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struct taos_data *taos = serio_get_drvdata(serio); |
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char *p; |
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/* Encode our transaction. "@" is for the device address, "$" for the |
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SMBus command and "#" for the data. */ |
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p = taos->buffer; |
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/* The device remembers the last used address, no need to send it |
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again if it's the same */ |
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if (addr != taos->addr) |
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p += sprintf(p, "@%02X", addr); |
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switch (size) { |
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case I2C_SMBUS_BYTE: |
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if (read_write == I2C_SMBUS_WRITE) |
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sprintf(p, "$#%02X", command); |
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else |
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sprintf(p, "$"); |
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break; |
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case I2C_SMBUS_BYTE_DATA: |
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if (read_write == I2C_SMBUS_WRITE) |
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sprintf(p, "$%02X#%02X", command, data->byte); |
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else |
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sprintf(p, "$%02X", command); |
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break; |
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default: |
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dev_warn(&adapter->dev, "Unsupported transaction %d\n", size); |
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return -EOPNOTSUPP; |
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} |
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/* Send the transaction to the TAOS EVM */ |
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dev_dbg(&adapter->dev, "Command buffer: %s\n", taos->buffer); |
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for (p = taos->buffer; *p; p++) |
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serio_write(serio, *p); |
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taos->addr = addr; |
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/* Start the transaction and read the answer */ |
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taos->pos = 0; |
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taos->state = TAOS_STATE_RECV; |
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serio_write(serio, read_write == I2C_SMBUS_WRITE ? '>' : '<'); |
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wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE, |
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msecs_to_jiffies(150)); |
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if (taos->state != TAOS_STATE_IDLE |
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|| taos->pos != 5) { |
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dev_err(&adapter->dev, "Transaction timeout (pos=%d)\n", |
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taos->pos); |
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return -EIO; |
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} |
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dev_dbg(&adapter->dev, "Answer buffer: %s\n", taos->buffer); |
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/* Interpret the returned string */ |
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p = taos->buffer + 1; |
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p[3] = '\0'; |
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if (!strcmp(p, "NAK")) |
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return -ENODEV; |
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if (read_write == I2C_SMBUS_WRITE) { |
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if (!strcmp(p, "ACK")) |
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return 0; |
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} else { |
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if (p[0] == 'x') { |
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/* |
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* Voluntarily dropping error code of kstrtou8 since all |
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* error code that it could return are invalid according |
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* to Documentation/i2c/fault-codes.rst. |
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*/ |
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if (kstrtou8(p + 1, 16, &data->byte)) |
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return -EPROTO; |
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return 0; |
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} |
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} |
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return -EIO; |
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} |
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static u32 taos_smbus_func(struct i2c_adapter *adapter) |
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{ |
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return I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA; |
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} |
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static const struct i2c_algorithm taos_algorithm = { |
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.smbus_xfer = taos_smbus_xfer, |
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.functionality = taos_smbus_func, |
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}; |
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static irqreturn_t taos_interrupt(struct serio *serio, unsigned char data, |
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unsigned int flags) |
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{ |
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struct taos_data *taos = serio_get_drvdata(serio); |
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switch (taos->state) { |
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case TAOS_STATE_INIT: |
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taos->buffer[taos->pos++] = data; |
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if (data == ':' |
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|| taos->pos == TAOS_BUFFER_SIZE - 1) { |
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taos->buffer[taos->pos] = '\0'; |
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taos->state = TAOS_STATE_IDLE; |
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wake_up_interruptible(&wq); |
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} |
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break; |
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case TAOS_STATE_EOFF: |
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taos->state = TAOS_STATE_IDLE; |
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wake_up_interruptible(&wq); |
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break; |
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case TAOS_STATE_RECV: |
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taos->buffer[taos->pos++] = data; |
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if (data == ']') { |
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taos->buffer[taos->pos] = '\0'; |
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taos->state = TAOS_STATE_IDLE; |
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wake_up_interruptible(&wq); |
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} |
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break; |
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} |
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return IRQ_HANDLED; |
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} |
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/* Extract the adapter name from the buffer received after reset. |
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The buffer is modified and a pointer inside the buffer is returned. */ |
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static char *taos_adapter_name(char *buffer) |
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{ |
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char *start, *end; |
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start = strstr(buffer, "TAOS "); |
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if (!start) |
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return NULL; |
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end = strchr(start, '\r'); |
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if (!end) |
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return NULL; |
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*end = '\0'; |
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return start; |
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} |
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static int taos_connect(struct serio *serio, struct serio_driver *drv) |
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{ |
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struct taos_data *taos; |
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struct i2c_adapter *adapter; |
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char *name; |
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int err; |
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taos = kzalloc(sizeof(struct taos_data), GFP_KERNEL); |
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if (!taos) { |
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err = -ENOMEM; |
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goto exit; |
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} |
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taos->state = TAOS_STATE_INIT; |
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serio_set_drvdata(serio, taos); |
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err = serio_open(serio, drv); |
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if (err) |
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goto exit_kfree; |
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adapter = &taos->adapter; |
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adapter->owner = THIS_MODULE; |
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adapter->algo = &taos_algorithm; |
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adapter->algo_data = serio; |
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adapter->dev.parent = &serio->dev; |
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/* Reset the TAOS evaluation module to identify it */ |
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serio_write(serio, TAOS_CMD_RESET); |
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wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE, |
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msecs_to_jiffies(2000)); |
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if (taos->state != TAOS_STATE_IDLE) { |
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err = -ENODEV; |
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dev_err(&serio->dev, "TAOS EVM reset failed (state=%d, " |
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"pos=%d)\n", taos->state, taos->pos); |
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goto exit_close; |
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} |
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name = taos_adapter_name(taos->buffer); |
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if (!name) { |
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err = -ENODEV; |
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dev_err(&serio->dev, "TAOS EVM identification failed\n"); |
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goto exit_close; |
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} |
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strlcpy(adapter->name, name, sizeof(adapter->name)); |
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/* Turn echo off for better performance */ |
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taos->state = TAOS_STATE_EOFF; |
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serio_write(serio, TAOS_CMD_ECHO_OFF); |
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wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE, |
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msecs_to_jiffies(250)); |
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if (taos->state != TAOS_STATE_IDLE) { |
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err = -ENODEV; |
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dev_err(&serio->dev, "TAOS EVM echo off failed " |
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"(state=%d)\n", taos->state); |
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goto exit_close; |
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} |
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err = i2c_add_adapter(adapter); |
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if (err) |
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goto exit_close; |
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dev_info(&serio->dev, "Connected to TAOS EVM\n"); |
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taos->client = taos_instantiate_device(adapter); |
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return 0; |
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exit_close: |
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serio_close(serio); |
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exit_kfree: |
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kfree(taos); |
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exit: |
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return err; |
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} |
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static void taos_disconnect(struct serio *serio) |
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{ |
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struct taos_data *taos = serio_get_drvdata(serio); |
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i2c_unregister_device(taos->client); |
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i2c_del_adapter(&taos->adapter); |
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serio_close(serio); |
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kfree(taos); |
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dev_info(&serio->dev, "Disconnected from TAOS EVM\n"); |
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} |
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static const struct serio_device_id taos_serio_ids[] = { |
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{ |
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.type = SERIO_RS232, |
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.proto = SERIO_TAOSEVM, |
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.id = SERIO_ANY, |
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.extra = SERIO_ANY, |
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}, |
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{ 0 } |
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}; |
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MODULE_DEVICE_TABLE(serio, taos_serio_ids); |
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static struct serio_driver taos_drv = { |
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.driver = { |
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.name = "taos-evm", |
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}, |
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.description = "TAOS evaluation module driver", |
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.id_table = taos_serio_ids, |
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.connect = taos_connect, |
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.disconnect = taos_disconnect, |
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.interrupt = taos_interrupt, |
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}; |
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module_serio_driver(taos_drv); |
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MODULE_AUTHOR("Jean Delvare <[email protected]>"); |
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MODULE_DESCRIPTION("TAOS evaluation module driver"); |
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MODULE_LICENSE("GPL");
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