[U-Boot] [PATCH] fsl_i2c: Add write-then-read transaction interface for I2C slave

[York Sun]

On 03/03/2014 12:58 AM, Shaveta Leekha wrote:
> Most of the I2C slaves support accesses in the typical style
> viz.read/write series of bytes at particular address offset.
> These transactions are currently supportd in the
> i2c driver using i2c_read and i2c_write APIs. I2C EEPROMs,
> RTC, etc fall in this category.
> The transactions look like:"
> START:Address:Tx:Offset:RESTART:Address[0..4]:Tx/Rx:data[0..n]:STOP"
> 
> However there are certain devices which support accesses in
> terms of the transactions as follows:
> "START:Address:Tx:Txdata[0..n1]:Clock_stretching:
>         RESTART:Address:Rx:data[0..n2]"
> 
> The Txdata is typically a command and some associated data,
> similarly Rxdata could be command status plus some data received
> as a response to the command sent.
> i2c_write_read() function provides support for such transactions
> (multiple bytes write followed by read)
> 
> Signed-off-by: Poonam Aggrwal <poonam.aggrwal at freescale.com>
> Signed-off-by: Shaveta Leekha <shaveta at freescale.com>
> ---
>  drivers/i2c/fsl_i2c.c  |   64 ++++++++++++++++++++++++++++++++++++++++++-----
>  drivers/i2c/i2c_core.c |    7 +++++
>  include/i2c.h          |   19 ++++++++++---
>  3 files changed, 78 insertions(+), 12 deletions(-)

<snip>

> diff --git a/include/i2c.h b/include/i2c.h
> index 1b4078e..7bac20a 100644
> --- a/include/i2c.h
> +++ b/include/i2c.h
> @@ -65,6 +65,9 @@ struct i2c_adapter {
>  	int		(*write)(struct i2c_adapter *adap, uint8_t chip,
>  				uint addr, int alen, uint8_t *buffer,
>  				int len);
> +	int		(*write_read)(struct i2c_adapter *adap, uint8_t chip,
> +				uint8_t *wbuffer, int wlength, uint8_t *rbuffer,
> +				int rlength);
>  	uint		(*set_bus_speed)(struct i2c_adapter *adap,
>  				uint speed);
>  	int		speed;
> @@ -75,13 +78,14 @@ struct i2c_adapter {
>  	char		*name;
>  };
>  
> -#define U_BOOT_I2C_MKENT_COMPLETE(_init, _probe, _read, _write, \
> +#define U_BOOT_I2C_MKENT_COMPLETE(_init, _probe, _read, _write, _write_read, \
>  		_set_speed, _speed, _slaveaddr, _hwadapnr, _name) \
>  	{ \
>  		.init		=	_init, \
>  		.probe		=	_probe, \
>  		.read		=	_read, \
>  		.write		=	_write, \
> +		.write_read	=	_write_read, \
>  		.set_bus_speed	=	_set_speed, \
>  		.speed		=	_speed, \
>  		.slaveaddr	=	_slaveaddr, \
> @@ -90,10 +94,11 @@ struct i2c_adapter {
>  		.name		=	#_name \
>  };
>  
> -#define U_BOOT_I2C_ADAP_COMPLETE(_name, _init, _probe, _read, _write, \
> -			_set_speed, _speed, _slaveaddr, _hwadapnr) \
> -	ll_entry_declare(struct i2c_adapter, _name, i2c) = \
> -	U_BOOT_I2C_MKENT_COMPLETE(_init, _probe, _read, _write, \
> +#define U_BOOT_I2C_ADAP_COMPLETE(_name, _init, _probe, _read, _write,	\
> +			_write_read, _set_speed, _speed, _slaveaddr,	\
> +			_hwadapnr)					\
> +	ll_entry_declare(struct i2c_adapter, _name, i2c) =		\
> +	U_BOOT_I2C_MKENT_COMPLETE(_init, _probe, _read, _write,  _write_read, \
>  		 _set_speed, _speed, _slaveaddr, _hwadapnr, _name);
>  
>  struct i2c_adapter *i2c_get_adapter(int index);
> @@ -237,6 +242,8 @@ int i2c_read(uint8_t chip, unsigned int addr, int alen,
>  
>  int i2c_write(uint8_t chip, unsigned int addr, int alen,
>  				uint8_t *buffer, int len);
> +int i2c_write_read(uint8_t chip, uchar *wbuffer, int wlen, uchar *rbuffer,
> +								int rlen);
>  
>  /*
>   * Utility routines to read/write registers.
> @@ -302,6 +309,8 @@ int i2c_probe(uchar chip);
>   */
>  int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len);
>  int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len);
> +int i2c_write_read(uchar chip, uchar *wbuffer, int wlen, uchar *rbuffer,
> +								int rlen);


You need to be careful when changing the header file. If you compile other
platforms, you will see the error. Try ./MAKEALL -a powerpc. I don't know how
bad you broke other architectures.

York