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

[Lukasz Majewski]

Hi Stefano,

> 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".
> 

Thanks for reply. 

Good point. I will move this to struct pmic.

Best regards,
Lukasz Majewski