static s32 i2c_smbus_xfer_emulated

static s32 i2c_smbus_xfer_emulated

[Kassey Lee]

hi, Jean:


here is the structur of i2c_msg,

         struct i2c_msg {
        __u16 addr;     /* slave address                        */
        __u16 flags;
#define I2C_M_TEN               0x0010  /* this is a ten bit chip address */
#define I2C_M_RD                0x0001  /* read data, from slave to master */
#define I2C_M_NOSTART           0x4000  /* if I2C_FUNC_PROTOCOL_MANGLING */
#define I2C_M_REV_DIR_ADDR      0x2000  /* if I2C_FUNC_PROTOCOL_MANGLING */
#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 */
        __u16 len;              /* msg length                           */
        __u8 *buf;              /* pointer to msg data                  */
};

do you think it is better to use __u8 other than unsigned char here ?
thanks

static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
                                   unsigned short flags,
                                   char read_write, u8 command, int size,
                                   union i2c_smbus_data *data)
{
        /* So we need to generate a series of msgs. In the case of writing, we
          need to use only one message; when reading, we need two. We initialize
          most things with sane defaults, to keep the code below somewhat
          simpler. */
        unsigned char msgbuf0[I2C_SMBUS_BLOCK_MAX+3];
        unsigned char msgbuf1[I2C_SMBUS_BLOCK_MAX+2];

        int num = read_write == I2C_SMBUS_READ ? 2 : 1;
        struct i2c_msg msg[2] = { { addr, flags, 1, msgbuf0 },
                                  { addr, flags | I2C_M_RD, 0, msgbuf1 }
                                };


--
Best regards
Kassey
Application Processor Systems Engineering, Marvell Technology Group Ltd.
Shanghai, China.

Re: static s32 i2c_smbus_xfer_emulated

[Jean Delvare]

On Tue, 14 Jun 2011 14:39:24 +0800, Kassey Lee wrote:
> hi, Jean:
> 
> 
> here is the structur of i2c_msg,
> 
>          struct i2c_msg {
>         __u16 addr;     /* slave address                        */
>         __u16 flags;
> #define I2C_M_TEN               0x0010  /* this is a ten bit chip address */
> #define I2C_M_RD                0x0001  /* read data, from slave to master */
> #define I2C_M_NOSTART           0x4000  /* if I2C_FUNC_PROTOCOL_MANGLING */
> #define I2C_M_REV_DIR_ADDR      0x2000  /* if I2C_FUNC_PROTOCOL_MANGLING */
> #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 */
>         __u16 len;              /* msg length                           */
>         __u8 *buf;              /* pointer to msg data                  */
> };
> 
> do you think it is better to use __u8 other than unsigned char here ?

What problem are you trying to solve, please?

> thanks
> 
> static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
>                                    unsigned short flags,
>                                    char read_write, u8 command, int size,
>                                    union i2c_smbus_data *data)
> {
>         /* So we need to generate a series of msgs. In the case of writing, we
>           need to use only one message; when reading, we need two. We initialize
>           most things with sane defaults, to keep the code below somewhat
>           simpler. */
>         unsigned char msgbuf0[I2C_SMBUS_BLOCK_MAX+3];
>         unsigned char msgbuf1[I2C_SMBUS_BLOCK_MAX+2];
> 
>         int num = read_write == I2C_SMBUS_READ ? 2 : 1;
>         struct i2c_msg msg[2] = { { addr, flags, 1, msgbuf0 },
>                                   { addr, flags | I2C_M_RD, 0, msgbuf1 }
>                                 };
> 
> 
-- 
Jean Delvare