On Tue, May 08, 2012 at 10:28:34PM +0530, Shubhrajyoti Datta wrote:
> Hi,
>
> On Tue, May 8, 2012 at 6:55 PM, Jayachandran C
> <jayachandranc@xxxxxxxxxxxxxxxxx> wrote:
> > From: Ganesan Ramalingam <ganesanr@xxxxxxxxxxxx>
> >
> > Some architectures supports only 16-bit or 32-bit read/write access
> > to their iospace. Add a 'regwidth' platform and OF parameter which
> > specifies the IO width to support these platforms.
> >
> > regwidth can be specified as 1, 2 or 4, and has a default value
> > of 1 if it is unspecified.
> >
> > Signed-off-by: Ganesan Ramalingam <ganesanr@xxxxxxxxxxxx>
> > Signed-off-by: Jayachandran C <jayachandranc@xxxxxxxxxxxxxxxxx>
> > ---
> > drivers/i2c/busses/i2c-ocores.c | 32 ++++++++++++++++++++++++++++++--
> > include/linux/i2c-ocores.h | 1 +
> > 2 files changed, 31 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/i2c/busses/i2c-ocores.c b/drivers/i2c/busses/i2c-ocores.c
> > index ebd2700..1313145 100644
> > --- a/drivers/i2c/busses/i2c-ocores.c
> > +++ b/drivers/i2c/busses/i2c-ocores.c
> > @@ -60,6 +64,7 @@
> > struct ocores_i2c {
> > void __iomem *base;
> > int regstep;
> > + int regwidth;
>
> Do we need it to be signed?
regstep and regwidth can be both unsigned, but since regstep is already
defined as int, we just followed that convention.
>
> > wait_queue_head_t wait;
> > struct i2c_adapter adap;
> > struct i2c_msg *msg;
> > @@ -102,12 +107,22 @@ struct ocores_i2c {
> >
> > static inline void oc_setreg(struct ocores_i2c *i2c, int reg, u8 value)
> > {
> > - iowrite8(value, i2c->base + reg * i2c->regstep);
> > + if (i2c->regwidth == 4)
> > + iowrite32(value, i2c->base + reg * i2c->regstep);
> > + else if (i2c->regwidth == 2)
> > + iowrite16(value, i2c->base + reg * i2c->regstep);
> > + else
> > + iowrite8(value, i2c->base + reg * i2c->regstep);
> > }
> >
> > static inline u8 oc_getreg(struct ocores_i2c *i2c, int reg)
>
> Shouldnt the return type also change?
>
No, the registers have only 8bit of data, and we do a 16/32 bit read and
return the lowest 8 bits.
Regards,
JC.
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