i2c: New bus driver for the TAOS evaluation modules
This is a new I2C bus driver for the TAOS evaluation modules. Developped
and tested on the TAOS TSL2550 EVM.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
diff --git a/drivers/i2c/busses/i2c-taos-evm.c b/drivers/i2c/busses/i2c-taos-evm.c
new file mode 100644
index 0000000..1b0cfd5
--- /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);