我用的是android2.3的源码，20111022发布的。在camera fimc驱动部分，我自己增加了一款sensor的驱动。做了如下修改：
(1)mach_mini6410.c:static struct i2c_board_info i2c_devs0[] __initdata = {
//{ I2C_BOARD_INFO("ov965x", 0x30), },
{ I2C_BOARD_INFO("ov7725", 0x21), },
(2)config_android_a70:CONFIG_OV7725=y
CONFIG_VIDEO_FIMC_CAM_RESET=0 //原先为1
(3)驱动部分代码如下：
static int ov7725_reg_read(struct i2c_client *client, unsigned char reg, unsigned char *val)
{
int ret;
unsigned char data[1] = {0};
struct i2c_msg msg = {
.addr = client->addr,
.flags = 0,
.len = 1,
.buf = data,
};
int retry = 0;
data[0] = reg;
do {
ret = i2c_transfer(client->adapter, &msg, 1);
if (ret == 1)
return 0;
retry++;
info("ov7725 : i2c transfer failed, retrying ret=%d\n",ret);
msleep(3);
} while (retry <= 10);
msg.flags = I2C_M_RD;
msg.len = 1;
ret = i2c_transfer(client->adapter, &msg, 1);
if (ret < 0)
{
info("%s i2c_transfer:2 ret = %d\n", __FUNCTION__, ret);
goto err;
}
*val = data[0];
info("%s 0x%04x = 0x%02x\n", __FUNCTION__, reg, data[0]);
return 0;
err:
dev_err(&client->dev, "Failed reading register 0x%02x!\n", reg);
return ret;
}
static int ov7725_detect(struct i2c_client *client)
{
unsigned char id_check[2] = {0};
ov7725_reg_read(client, 0x0A, &id_check[0]);
ov7725_reg_read(client, 0x0B, &id_check[1]);
if((id_check[0] != 0x77) || (id_check[1] != 0x21))
return -1;
dev_info(&client->dev, "Detected a ov7725 chip\n");
return 0;
}
static int ov7725_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
struct ov7725_state *ov7725_state;
struct v4l2_subdev *sd;
int ret;
info("****************%s****************\n", __func__);
ov7725_state = kzalloc(sizeof(struct ov7725_state), GFP_KERNEL);
if (ov7725_state == NULL)
{
info("*************ov7725:ov7725_state == NULL*****************\n");
return -ENOMEM;
}
ov7725_state->i2c_client = client;
sd = &ov7725_state->sd;
strcpy(sd->name, "ov7725");
/* Registering subdev */
v4l2_i2c_subdev_init(sd, client, &ov7725_ops);
ret = ov7725_detect(client);
if (ret) {
dev_info(&client->dev, "ov7725 sensor not found\n");
goto err;
}
info("*************ov7725 has been probed*****************\n");
return 0;
err:
kfree(ov7725_state);
info("*************ov7725 probed error:ret=%d*****************\n",ret);
return 0;
}
static int ov7725_remove(struct i2c_client *client)
{
struct v4l2_subdev *sd = i2c_get_clientdata(client);
info("****************%s****************\n", __func__);
v4l2_device_unregister_subdev(sd);
kfree(to_state(sd));
return 0;
}
static const struct i2c_device_id ov7725_id[] = {
{ "ov7725", 0 },
{ },
};
MODULE_DEVICE_TABLE(i2c, ov7725_id);
static struct v4l2_i2c_driver_data v4l2_i2c_data = {
.name = "ov7725",
.probe = ov7725_probe,
.remove = ov7725_remove,
.id_table = ov7725_id,
};
代码已成功编译到FIMC驱动中去，并且开机的时候跑到了probe函数，但是在跑到i2c_transfer的时候执行adap->algo->master_xfer(adap, msgs, num)返回-6，
我查了这个错误是no such device or address,
但是我测试三路电压都是正常的，并且同样的sensor和硬件设备我在android2.1上面是可以跑起来的，所以硬件应该没有问题吧。
我现在不知道问题出在哪了，请求各位大侠指点，不胜感激！
