diff options
| -rw-r--r-- | Documentation/i2c/busses/i2c-taos-evm | 46 | ||||
| -rw-r--r-- | drivers/i2c/busses/Kconfig | 16 | ||||
| -rw-r--r-- | drivers/i2c/busses/Makefile | 1 | ||||
| -rw-r--r-- | drivers/i2c/busses/i2c-taos-evm.c | 330 | ||||
| -rw-r--r-- | include/linux/serio.h | 1 |
5 files changed, 394 insertions, 0 deletions
diff --git a/Documentation/i2c/busses/i2c-taos-evm b/Documentation/i2c/busses/i2c-taos-evm new file mode 100644 index 00000000000..9146e33be6d --- /dev/null +++ b/Documentation/i2c/busses/i2c-taos-evm @@ -0,0 +1,46 @@ +Kernel driver i2c-taos-evm + +Author: Jean Delvare <khali@linux-fr.org> + +This is a driver for the evaluation modules for TAOS I2C/SMBus chips. +The modules include an SMBus master with limited capabilities, which can +be controlled over the serial port. Virtually all evaluation modules +are supported, but a few lines of code need to be added for each new +module to instantiate the right I2C chip on the bus. Obviously, a driver +for the chip in question is also needed. + +Currently supported devices are: + +* TAOS TSL2550 EVM + +For addtional information on TAOS products, please see + http://www.taosinc.com/ + + +Using this driver +----------------- + +In order to use this driver, you'll need the serport driver, and the +inputattach tool, which is part of the input-utils package. The following +commands will tell the kernel that you have a TAOS EVM on the first +serial port: + +# modprobe serport +# inputattach --taos-evm /dev/ttyS0 + + +Technical details +----------------- + +Only 4 SMBus transaction types are supported by the TAOS evaluation +modules: +* Receive Byte +* Send Byte +* Read Byte +* Write Byte + +The communication protocol is text-based and pretty simple. It is +described in a PDF document on the CD which comes with the evaluation +module. The communication is rather slow, because the serial port has +to operate at 1200 bps. However, I don't think this is a big concern in +practice, as these modules are meant for evaluation and testing only. diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index 165c1266fff..c093b070015 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -513,6 +513,22 @@ config I2C_SIS96X This driver can also be built as a module. If so, the module will be called i2c-sis96x. +config I2C_TAOS_EVM + tristate "TAOS evaluation module" + depends on EXPERIMENTAL + select SERIO + select SERIO_SERPORT + default n + help + This supports TAOS evaluation modules on serial port. In order to + use this driver, you will need the inputattach tool, which is part + of the input-utils package. + + If unsure, say N. + + This support is also available as a module. If so, the module + will be called i2c-taos-evm. + config I2C_STUB tristate "I2C/SMBus Test Stub" depends on EXPERIMENTAL && m diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile index 14d1432f698..a49c0a386ae 100644 --- a/drivers/i2c/busses/Makefile +++ b/drivers/i2c/busses/Makefile @@ -44,6 +44,7 @@ obj-$(CONFIG_I2C_SIS5595) += i2c-sis5595.o obj-$(CONFIG_I2C_SIS630) += i2c-sis630.o obj-$(CONFIG_I2C_SIS96X) += i2c-sis96x.o obj-$(CONFIG_I2C_STUB) += i2c-stub.o +obj-$(CONFIG_I2C_TAOS_EVM) += i2c-taos-evm.o obj-$(CONFIG_I2C_TINY_USB) += i2c-tiny-usb.o obj-$(CONFIG_I2C_VERSATILE) += i2c-versatile.o obj-$(CONFIG_I2C_ACORN) += i2c-acorn.o diff --git a/drivers/i2c/busses/i2c-taos-evm.c b/drivers/i2c/busses/i2c-taos-evm.c new file mode 100644 index 00000000000..1b0cfd5472f --- /dev/null +++ b/drivers/i2c/busses/i2c-taos-evm.c @@ -0,0 +1,330 @@ +/* + * Driver for the TAOS evaluation modules + * These devices include an I2C master which can be controlled over the + * serial port. + * + * Copyright (C) 2007 Jean Delvare <khali@linux-fr.org> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; version 2 of the License. + * + * 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, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include <linux/delay.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/interrupt.h> +#include <linux/input.h> +#include <linux/serio.h> +#include <linux/init.h> +#include <linux/i2c.h> + +#define TAOS_BUFFER_SIZE 63 + +#define TAOS_STATE_INIT 0 +#define TAOS_STATE_IDLE 1 +#define TAOS_STATE_SEND 2 +#define TAOS_STATE_RECV 3 + +#define TAOS_CMD_RESET 0x12 + +static DECLARE_WAIT_QUEUE_HEAD(wq); + +struct taos_data { + struct i2c_adapter adapter; + struct i2c_client *client; + int state; + u8 addr; /* last used address */ + unsigned char buffer[TAOS_BUFFER_SIZE]; + unsigned int pos; /* position inside the buffer */ +}; + +/* TAOS TSL2550 EVM */ +static struct i2c_board_info tsl2550_info = { + I2C_BOARD_INFO("tsl2550", 0x39), + .type = "tsl2550", +}; + +/* Instantiate i2c devices based on the adapter name */ +static struct i2c_client *taos_instantiate_device(struct i2c_adapter *adapter) +{ + if (!strncmp(adapter->name, "TAOS TSL2550 EVM", 16)) { + dev_info(&adapter->dev, "Instantiating device %s at 0x%02x\n", + tsl2550_info.driver_name, tsl2550_info.addr); + return i2c_new_device(adapter, &tsl2550_info); + } + + return NULL; +} + +static int taos_smbus_xfer(struct i2c_adapter *adapter, u16 addr, + unsigned short flags, char read_write, u8 command, + int size, union i2c_smbus_data *data) +{ + struct serio *serio = adapter->algo_data; + struct taos_data *taos = serio_get_drvdata(serio); + char *p; + + /* Encode our transaction. "@" is for the device address, "$" for the + SMBus command and "#" for the data. */ + p = taos->buffer; + + /* The device remembers the last used address, no need to send it + again if it's the same */ + if (addr != taos->addr) + p += sprintf(p, "@%02X", addr); + + switch (size) { + case I2C_SMBUS_BYTE: + if (read_write == I2C_SMBUS_WRITE) + sprintf(p, "$#%02X", command); + else + sprintf(p, "$"); + break; + case I2C_SMBUS_BYTE_DATA: + if (read_write == I2C_SMBUS_WRITE) + sprintf(p, "$%02X#%02X", command, data->byte); + else + sprintf(p, "$%02X", command); + break; + default: + dev_dbg(&adapter->dev, "Unsupported transaction size %d\n", + size); + return -EINVAL; + } + + /* Send the transaction to the TAOS EVM */ + dev_dbg(&adapter->dev, "Command buffer: %s\n", taos->buffer); + taos->pos = 0; + taos->state = TAOS_STATE_SEND; + serio_write(serio, taos->buffer[0]); + wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE, + msecs_to_jiffies(250)); + if (taos->state != TAOS_STATE_IDLE) { + dev_err(&adapter->dev, "Transaction failed " + "(state=%d, pos=%d)\n", taos->state, taos->pos); + taos->addr = 0; + return -EIO; + } + taos->addr = addr; + + /* Start the transaction and read the answer */ + taos->pos = 0; + taos->state = TAOS_STATE_RECV; + serio_write(serio, read_write == I2C_SMBUS_WRITE ? '>' : '<'); + wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE, + msecs_to_jiffies(150)); + if (taos->state != TAOS_STATE_IDLE + || taos->pos != 6) { + dev_err(&adapter->dev, "Transaction timeout (pos=%d)\n", + taos->pos); + return -EIO; + } + dev_dbg(&adapter->dev, "Answer buffer: %s\n", taos->buffer); + + /* Interpret the returned string */ + p = taos->buffer + 2; + p[3] = '\0'; + if (!strcmp(p, "NAK")) + return -ENODEV; + + if (read_write == I2C_SMBUS_WRITE) { + if (!strcmp(p, "ACK")) + return 0; + } else { + if (p[0] == 'x') { + data->byte = simple_strtol(p + 1, NULL, 16); + return 0; + } + } + + return -EIO; +} + +static u32 taos_smbus_func(struct i2c_adapter *adapter) +{ + return I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA; +} + +static const struct i2c_algorithm taos_algorithm = { + .smbus_xfer = taos_smbus_xfer, + .functionality = taos_smbus_func, +}; + +static irqreturn_t taos_interrupt(struct serio *serio, unsigned char data, + unsigned int flags) +{ + struct taos_data *taos = serio_get_drvdata(serio); + + switch (taos->state) { + case TAOS_STATE_INIT: + taos->buffer[taos->pos++] = data; + if (data == ':' + || taos->pos == TAOS_BUFFER_SIZE - 1) { + taos->buffer[taos->pos] = '\0'; + taos->state = TAOS_STATE_IDLE; + wake_up_interruptible(&wq); + } + break; + case TAOS_STATE_SEND: + if (taos->buffer[++taos->pos]) + serio_write(serio, taos->buffer[taos->pos]); + else { + taos->state = TAOS_STATE_IDLE; + wake_up_interruptible(&wq); + } + break; + case TAOS_STATE_RECV: + taos->buffer[taos->pos++] = data; + if (data == ']') { + taos->buffer[taos->pos] = '\0'; + taos->state = TAOS_STATE_IDLE; + wake_up_interruptible(&wq); + } + break; + } + + return IRQ_HANDLED; +} + +/* Extract the adapter name from the buffer received after reset. + The buffer is modified and a pointer inside the buffer is returned. */ +static char *taos_adapter_name(char *buffer) +{ + char *start, *end; + + start = strstr(buffer, "TAOS "); + if (!start) + return NULL; + + end = strchr(start, '\r'); + if (!end) + return NULL; + *end = '\0'; + + return start; +} + +static int taos_connect(struct serio *serio, struct serio_driver *drv) +{ + struct taos_data *taos; + struct i2c_adapter *adapter; + char *name; + int err; + + taos = kzalloc(sizeof(struct taos_data), GFP_KERNEL); + if (!taos) { + err = -ENOMEM; + goto exit; + } + taos->state = TAOS_STATE_INIT; + serio_set_drvdata(serio, taos); + + err = serio_open(serio, drv); + if (err) + goto exit_kfree; + + adapter = &taos->adapter; + adapter->owner = THIS_MODULE; + adapter->algo = &taos_algorithm; + adapter->algo_data = serio; + adapter->dev.parent = &serio->dev; + + /* Reset the TAOS evaluation module to identify it */ + serio_write(serio, TAOS_CMD_RESET); + wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE, + msecs_to_jiffies(2000)); + + if (taos->state != TAOS_STATE_IDLE) { + err = -ENODEV; + dev_dbg(&serio->dev, "TAOS EVM reset failed (state=%d, " + "pos=%d)\n", taos->state, taos->pos); + goto exit_close; + } + + name = taos_adapter_name(taos->buffer); + if (!name) { + err = -ENODEV; + dev_err(&serio->dev, "TAOS EVM identification failed\n"); + goto exit_close; + } + strlcpy(adapter->name, name, sizeof(adapter->name)); + + err = i2c_add_adapter(adapter); + if (err) + goto exit_close; + dev_dbg(&serio->dev, "Connected to TAOS EVM\n"); + + taos->client = taos_instantiate_device(adapter); + return 0; + + exit_close: + serio_close(serio); + exit_kfree: + serio_set_drvdata(serio, NULL); + kfree(taos); + exit: + return err; +} + +static void taos_disconnect(struct serio *serio) +{ + struct taos_data *taos = serio_get_drvdata(serio); + + if (taos->client) + i2c_unregister_device(taos->client); + i2c_del_adapter(&taos->adapter); + serio_close(serio); + serio_set_drvdata(serio, NULL); + kfree(taos); + + dev_dbg(&serio->dev, "Disconnected from TAOS EVM\n"); +} + +static struct serio_device_id taos_serio_ids[] = { + { + .type = SERIO_RS232, + .proto = SERIO_TAOSEVM, + .id = SERIO_ANY, + .extra = SERIO_ANY, + }, + { 0 } +}; +MODULE_DEVICE_TABLE(serio, taos_serio_ids); + +static struct serio_driver taos_drv = { + .driver = { + .name = "taos-evm", + }, + .description = "TAOS evaluation module driver", + .id_table = taos_serio_ids, + .connect = taos_connect, + .disconnect = taos_disconnect, + .interrupt = taos_interrupt, +}; + +static int __init taos_init(void) +{ + return serio_register_driver(&taos_drv); +} + +static void __exit taos_exit(void) +{ + serio_unregister_driver(&taos_drv); +} + +MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>"); +MODULE_DESCRIPTION("TAOS evaluation module driver"); +MODULE_LICENSE("GPL"); + +module_init(taos_init); +module_exit(taos_exit); diff --git a/include/linux/serio.h b/include/linux/serio.h index 1ebf0455e22..d9377ce9ffd 100644 --- a/include/linux/serio.h +++ b/include/linux/serio.h @@ -209,5 +209,6 @@ static inline void serio_unpin_driver(struct serio *serio) #define SERIO_PENMOUNT 0x31 #define SERIO_TOUCHRIGHT 0x32 #define SERIO_TOUCHWIN 0x33 +#define SERIO_TAOSEVM 0x34 #endif |