[U-Boot] [PATCH 02/16] pmic:i2c: Add I2C byte order to PMIC framework

[Stefano Babic]

On 14/09/2012 17:40, Lukasz Majewski wrote:
> Since the pmic_reg_read is the u32 value, the order in which bytes
> are placed to form u32 value is important.
> 
> This commit adds the reverse (which is default) and normal byte order.
> 
> Signed-off-by: Lukasz Majewski <l.majewski at samsung.com>
> Signed-off-by: Kyungmin Park <kyungmin.park at samsung.com>
> ---

Hi,

>  drivers/misc/pmic_i2c.c |   31 ++++++++++++++++++++++++-------
>  include/pmic.h          |    3 +++
>  2 files changed, 27 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/misc/pmic_i2c.c b/drivers/misc/pmic_i2c.c
> index e74c372..1aa5b7b 100644
> --- a/drivers/misc/pmic_i2c.c
> +++ b/drivers/misc/pmic_i2c.c
> @@ -40,13 +40,24 @@ int pmic_reg_write(struct pmic *p, u32 reg, u32 val)
>  
>  	switch (pmic_i2c_tx_num) {
>  	case 3:
> -		buf[0] = (val >> 16) & 0xff;
> -		buf[1] = (val >> 8) & 0xff;
> -		buf[2] = val & 0xff;
> +		if (pmic_i2c_byte_order == PMIC_BYTE_ORDER_NORMAL) {
> +			buf[2] = (val >> 16) & 0xff;
> +			buf[1] = (val >> 8) & 0xff;
> +			buf[0] = val & 0xff;
> +		} else {
> +			buf[0] = (val >> 16) & 0xff;
> +			buf[1] = (val >> 8) & 0xff;
> +			buf[2] = val & 0xff;
> +		}
>  		break;
>  	case 2:
> -		buf[0] = (val >> 8) & 0xff;
> -		buf[1] = val & 0xff;
> +		if (pmic_i2c_byte_order == PMIC_BYTE_ORDER_NORMAL) {
> +			buf[1] = (val >> 8) & 0xff;
> +			buf[0] = val & 0xff;
> +		} else {
> +			buf[0] = (val >> 8) & 0xff;
> +			buf[1] = val & 0xff;
> +		}
>  		break;
>  	case 1:
>  		buf[0] = val & 0xff;
> @@ -75,10 +86,16 @@ int pmic_reg_read(struct pmic *p, u32 reg, u32 *val)
>  
>  	switch (pmic_i2c_tx_num) {
>  	case 3:
> -		ret_val = buf[0] << 16 | buf[1] << 8 | buf[2];
> +		if (pmic_i2c_byte_order == PMIC_BYTE_ORDER_NORMAL)
> +			ret_val = buf[2] << 16 | buf[1] << 8 | buf[0];
> +		else
> +			ret_val = buf[0] << 16 | buf[1] << 8 | buf[2];
>  		break;
>  	case 2:
> -		ret_val = buf[0] << 8 | buf[1];
> +		if (pmic_i2c_byte_order == PMIC_BYTE_ORDER_NORMAL)
> +			ret_val = buf[1] << 8 | buf[0];
> +		else
> +			ret_val = buf[0] << 8 | buf[1];
>  		break;
>  	case 1:
>  		ret_val = buf[0];
> diff --git a/include/pmic.h b/include/pmic.h
> index 6a05b40..2166f73 100644
> --- a/include/pmic.h
> +++ b/include/pmic.h
> @@ -27,11 +27,13 @@
>  enum { PMIC_I2C, PMIC_SPI, };
>  enum { I2C_PMIC, I2C_NUM, };
>  enum { PMIC_READ, PMIC_WRITE, };
> +enum { PMIC_BYTE_ORDER_REVERSED, PMIC_BYTE_ORDER_NORMAL, };
>  
>  struct p_i2c {
>  	unsigned char addr;
>  	unsigned char *buf;
>  	unsigned char tx_num;
> +	unsigned char byte_order;

I can imagine we could have the same issue with SPI and not only with
I2C. The byte order is not strictly related to the interface type, and I
think this should add to the "struct pmic" instead of the "struct p_i2c".

Regards,
Stefano Babic

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