TDA8029模块工作之I2C修改支持ALPAR协议
TDA8029是一个完全单芯片、低成本、低功耗、功能强大的智能读卡器。它具有多种用来减少功耗的模式以及宽的电源电压范围，使之非常适合使用在便携式 设备中。由于具有特殊的多用途硬件，小嵌入式软件程序能够控制市场上的大部份卡。
由于我们产品的串口都已经被占用，TDA8029支持非标准I2C方式访问数据，所以我们改用I2C方式。CPU的I2C有标准I2C和GPIO I2C两种方式。由于TDA8029的I2C协议不是标准I2C，需要进行修改。所以我们选择从GPIO I2C方式中进行简单修改以支持ALPAR协议访问格式。
下面是ALPAR协议格式：
由上图可知，协议发送或接收的数据长度在数据的第二第三字节定义。因此，我们只需要在读取数据过程中先得出数据长度即可。
以下部分是修改的代码, +为添加部分：
P { margin-bottom: 5.25px; }Index: include/linux/i2c.h
===================================================================
--- include/linux/i2c.h (版本 986)
+++ include/linux/i2c.h (版本 988)
@@ -90,6 +90,12 @@
u8 command, u8 *values);
extern s32 i2c_smbus_write_block_data(struct i2c_client *client,
u8 command, u8 length, const u8 *values);
+/*
+* iUnin add for tda8029 ALPAR protocol. by yang.yuanming.
+* data: ACK(1) + length(2) + code(1) + data(n) +LRC(1) = n+5 n=0~506
+*/
+extern s32 i2c_smbus_read_alpar_data(struct i2c_client *client, u8 *values);
+extern s32 i2c_smbus_write_alpar_data(struct i2c_client *client, u8 length, const u8 *values);
/* Returns the number of read bytes */
extern s32 i2c_smbus_read_i2c_block_data(struct i2c_client *client,
u8 command, u8 length, u8 *values);
@@ -511,6 +517,7 @@
#define I2C_M_IGNORE_NAK 0x1000 /* if I2C_FUNC_PROTOCOL_MANGLING */
#define I2C_M_NO_RD_ACK 0x0800 /* if I2C_FUNC_PROTOCOL_MANGLING */
#define I2C_M_RECV_LEN 0x0400 /* length will be first received byte */
+#define I2C_M_ALPAR_RECV_LEN 0x0200 /* length will be n2&0xFF+n3+5 received byte */
__u16 len; /* msg length */
__u8 *buf; /* pointer to msg data */
};
@@ -566,6 +573,18 @@
/* and one more for user-space compatibility */
};
+/*
+* iUnin add for tda8029 ALPAR protocol. by yang.yuanming.
+* data: ACK(1) + length(2) + code(1) + data(n) +LRC(1) = n+5 n=0~506
+*/
+#define I2C_SMBUS_ALPAR_MAX 512 /* As specified in SMBus standard */
+union i2c_alpar_data {
+ __u8 byte;
+ __u16 word;
+ __u8 block[I2C_SMBUS_ALPAR_MAX]; /* block[0] is used for length */
+ /* and one more for user-space compatibility */
+};
+
/* i2c_smbus_xfer read or write markers */
#define I2C_SMBUS_READ 1
#define I2C_SMBUS_WRITE 0
@@ -581,5 +600,5 @@
#define I2C_SMBUS_I2C_BLOCK_BROKEN 6
#define I2C_SMBUS_BLOCK_PROC_CALL 7 /* SMBus 2.0 */
#define I2C_SMBUS_I2C_BLOCK_DATA 8
-
+#define I2C_SMBUS_ALPAR_DATA 9
#endif /* _LINUX_I2C_H */
Index: drivers/i2c/i2c-core.c
===================================================================
--- drivers/i2c/i2c-core.c (版本 986)
+++ drivers/i2c/i2c-core.c (版本 988)
@@ -1803,6 +1803,70 @@
}
EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data);
+
+/*
+* iUnin add for tda8029 ALPAR protocol. by yang.yuanming.
+* data: ACK(1) + length(2) + code(1) + data(n) +LRC(1) = n+5
+*/
+s32 i2c_smbus_read_alpar_data(struct i2c_client *client, u8 *values)
+{
+ union i2c_alpar_data data;
+ int status;
+ unsigned char msgbuf0[I2C_SMBUS_ALPAR_MAX];
+ int num = 1;
+ struct i2c_msg msg[1] = {{ client->addr, client->flags | I2C_M_RD, 0, msgbuf0 }
+ };
+
+ int i, alpar_len;
+ u8 partial_pec = 0;
+
+ msg[0].flags |= I2C_M_ALPAR_RECV_LEN;
+ msg[0].len = 5; /* block length will be added by the underlying bus driver */
+
+ status = i2c_transfer(client->adapter, msg, num);
+ if (status < 0)
+ return status;
+
+ /* Check PEC if last message is a read */
+ if (i && (msg[num-1].flags & I2C_M_RD)) {
+ status = i2c_smbus_check_pec(partial_pec, &msg[num-1]);
+ if (status < 0)
+ return status;
+ }
+
+ alpar_len = (msgbuf0[1]*256 +msgbuf0[2] + 5);
+ for (i = 0; i < alpar_len; i++)
+ data.block[i] = msgbuf0[i];
+
+ memcpy(values, &data.block[0], alpar_len);
+
+ return alpar_len;
+}
+EXPORT_SYMBOL(i2c_smbus_read_alpar_data);
+
+/*
+* iUnin add for tda8029 ALPAR protocol. by yang.yuanming.
+* data: ACK(1) + length(2) + code(1) + data(n) +LRC(1) = n+5
+*/
+s32 i2c_smbus_write_alpar_data(struct i2c_client *client, u8 length, const u8 *values)
+{
+ int status;
+
+ if (length > I2C_SMBUS_ALPAR_MAX)
+ length = I2C_SMBUS_ALPAR_MAX;
+
+ struct i2c_msg msg[1] = {{ client->addr, 0, length, values }
+ };
+
+ status = i2c_transfer(client->adapter, msg, 1);
+ if (status < 0)
+ return status;
+
+ return 0;
+}
+EXPORT_SYMBOL(i2c_smbus_write_alpar_data);
+
+
/* Simulate a SMBus command using the i2c protocol
No checking of parameters is done! */
static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
Index: drivers/i2c/algos/i2c-algo-bit.c
===================================================================
--- drivers/i2c/algos/i2c-algo-bit.c (版本 986)
+++ drivers/i2c/algos/i2c-algo-bit.c (版本 988)
@@ -417,6 +417,25 @@
temp++;
count--;
+ /*
+ * iUnin add for tda8029 ALPAR protocol. by yang.yuanming.
+ * data: ACK(1) + length(2) + code(1) + data(n) +LRC(1) = n+5
+ */
+ if ((rdcount == 2 || rdcount == 3) && (flags & I2C_M_ALPAR_RECV_LEN)) {
+ /* The original count value accounts for the extra
+ bytes, that is, either 1 for a regular transaction,
+ or 2 for a PEC transaction. */
+ if(rdcount == 2){
+ count += (inval*256);
+ msg->len += (inval*256);
+ }
+ if(rdcount == 3){
+ count += inval;
+ msg->len += inval;
+ }
+
+ }
+
/* Some SMBus transactions require that we receive the
transaction length as the first read byte. */
if (rdcount == 1 && (flags & I2C_M_RECV_LEN)) {