#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/i2c.h>
#include <linux/smp_lock.h>
#define I2C_API_FAKE_ADDR 0x7f
#define I2C_MINORS 256
int i2c_api_attach(struct i2c_adapter *adapter);
int i2c_api_detach(struct i2c_adapter *adapter);
struct i2c_api {
struct list_head list;
struct i2c_client *client;
};
static LIST_HEAD(i2c_api_list);
static DEFINE_SPINLOCK(i2c_api_list_lock);
static const unsigned short normal_addr[] = { I2C_API_FAKE_ADDR, I2C_CLIENT_END };
static const unsigned short ignore[] = { I2C_CLIENT_END };
static struct i2c_client_address_data addr_data =
{
.normal_i2c = normal_addr,
.probe = ignore,
.ignore = ignore,
.forces = NULL,
};
static const struct i2c_device_id id[] = {
{"I2C-API", 0},
{}
};
MODULE_DEVICE_TABLE(i2c, id);
static struct i2c_driver i2c_api_driver = {
.id_table = id,
.attach_adapter = i2c_api_attach,
.detach_adapter = i2c_api_detach,
.command = NULL,
.driver = {
.name = "I2C-API",
.owner = THIS_MODULE,
},
.address_data = &addr_data,
};
static struct i2c_api *get_i2c_api(int bus_id)
{
struct i2c_api *i2c_api;
spin_lock(&i2c_api_list_lock);
list_for_each_entry(i2c_api, &i2c_api_list, list) {
if (i2c_api->client->adapter->nr == bus_id)
goto found;
}
i2c_api = NULL;
found:
spin_unlock(&i2c_api_list_lock);
return i2c_api;
}
static struct i2c_api *add_i2c_api(struct i2c_client *client)
{
struct i2c_api *i2c_api;
if (client->adapter->nr >= I2C_MINORS) {
printk(KERN_ERR "i2c_api: Out of device minors (%d)/n",
client->adapter->nr);
return NULL;
}
i2c_api = kzalloc(sizeof(*i2c_api), GFP_KERNEL);
if (!i2c_api)
return NULL;
i2c_api->client = client;
spin_lock(&i2c_api_list_lock);
list_add_tail(&i2c_api->list, &i2c_api_list);
spin_unlock(&i2c_api_list_lock);
return i2c_api;
}
static void del_i2c_api(struct i2c_api *i2c_api)
{
spin_lock(&i2c_api_list_lock);
list_del(&i2c_api->list);
spin_unlock(&i2c_api_list_lock);
kfree(i2c_api);
}
static int i2c_api_do_xfer(int bus_id, char chip_addr, char sub_addr, int mode,
char *buf, unsigned int size)
{
/** you could define more transfer mode here, implement it following. */
#define I2C_API_XFER_MODE_SEND 0x0 /* standard send */
#define I2C_API_XFER_MODE_RECV 0x1 /* standard receive */
#define I2C_API_XFER_MODE_SEND_NO_SUBADDR 0x2 /* send without sub-address */
#define I2C_API_XFER_MODE_RECV_NO_SUBADDR 0x3 /* receive without sub-address */
int ret = 0;
char *tmp;
struct i2c_api *i2c_api = get_i2c_api(bus_id);
if (!i2c_api)
return -ENODEV;
i2c_api->client->addr = chip_addr;
switch (mode) {
case I2C_API_XFER_MODE_SEND:
tmp = kmalloc(size + 1,GFP_KERNEL);
if (tmp == NULL)
return -ENOMEM;
tmp[0] = sub_addr;
memcpy(&tmp[1], buf, size);
ret = i2c_master_send(i2c_api->client, tmp, size + 1);
ret = (ret == size + 1) ? size : ret;
break;
case I2C_API_XFER_MODE_RECV:
ret = i2c_master_send(i2c_api->client, &sub_addr, 1);
if (ret < 0)
return ret;
ret = i2c_master_recv(i2c_api->client, buf, size);
break;
case I2C_API_XFER_MODE_SEND_NO_SUBADDR:
ret = i2c_master_send(i2c_api->client, buf, size);
break;
case I2C_API_XFER_MODE_RECV_NO_SUBADDR:
ret = i2c_master_recv(i2c_api->client, buf, size);
break;
default:
return -EINVAL;
}
return ret;
}
int i2c_api_do_send(int bus_id, char chip_addr, char sub_addr, char *buf, unsigned int size)
{
return i2c_api_do_xfer(bus_id, chip_addr, sub_addr, I2C_API_XFER_MODE_SEND, buf, size);
}
int i2c_api_do_recv(int bus_id, char chip_addr, char sub_addr, char *buf, unsigned int size)
{
return i2c_api_do_xfer(bus_id, chip_addr, sub_addr, I2C_API_XFER_MODE_RECV, buf, size);
}
int i2c_api_attach(struct i2c_adapter *adap)
{
struct i2c_board_info info;
struct i2c_client *client;
memset(&info, 0, sizeof(struct i2c_board_info));
strlcpy(info.type, "i2c_api", I2C_NAME_SIZE);
info.addr = I2C_API_FAKE_ADDR;
client = i2c_new_device(adap, &info);
if (client)
add_i2c_api(client);
printk(KERN_INFO "i2c_api_attach adap[%d]/n", adap->nr);
return 0;
}
int i2c_api_detach(struct i2c_adapter *adap)
{
struct i2c_api *i2c_api;
i2c_api = get_i2c_api(adap->nr);
if (i2c_api)
del_i2c_api(i2c_api);
return 0;
}
static int __init i2c_api_init(void)
{
int ret = i2c_add_driver(&i2c_api_driver);
if (ret) {
printk(KERN_ERR "[%s] Driver registration failed, module not inserted./n", __func__);
return ret;
}
return 0 ;
}
static void __exit i2c_api_exit(void)
{
i2c_del_driver(&i2c_api_driver);
}
MODULE_AUTHOR("Loon, <[email protected]>");
MODULE_DESCRIPTION("I2C i2c_api Driver");
MODULE_LICENSE("GPL");
module_init(i2c_api_init);
module_exit(i2c_api_exit);
EXPORT_SYMBOL_GPL(i2c_api_do_send);
EXPORT_SYMBOL_GPL(i2c_api_do_recv);
