Re: [PATCH v5 4/7] pinctrl: freescale: imx: allow mux_reg offset zero

[Shawn Guo <shawnguo@kernel.org>]

On Fri, Sep 25, 2015 at 12:47:26PM +0200, Markus Pargmann wrote:
> On Thu, Sep 24, 2015 at 03:54:00PM -0500, Adrian Alonso wrote:
> > Allow mux_reg offset zero to be a valid pin_id, on imx7d
> > mux_conf reg offset is zero for iomuxc-lspr controller
> > 
> > Signed-off-by: Adrian Alonso <aalonso@freescale.com>
> > ---
> > Changes for V2: Resend
> > Changes for V3: Resend
> > Changes for V4: Simplify pin_id assigment when ZERO_OFFSET_VALID is set
> > Changes for V5:
> > - Drop patch pinctrl: freescale: imx: add ZERO_OFFSET_VALID flag
> > - Allow mux_reg ZERO OFFSET as pin_id
> > 
> >  drivers/pinctrl/freescale/pinctrl-imx.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/pinctrl/freescale/pinctrl-imx.c b/drivers/pinctrl/freescale/pinctrl-imx.c
> > index b9c6deb..23348d8 100644
> > --- a/drivers/pinctrl/freescale/pinctrl-imx.c
> > +++ b/drivers/pinctrl/freescale/pinctrl-imx.c
> > @@ -550,7 +550,7 @@ static int imx_pinctrl_parse_groups(struct device_node *np,
> >  				conf_reg = -1;
> >  		}
> >  
> > -		pin_id = mux_reg ? mux_reg / 4 : conf_reg / 4;
> > +		pin_id = (mux_reg != -1) ? mux_reg / 4 : conf_reg / 4;
> 
> This will break compatibility with imx35 and imx25 pinctrl drivers. They
> have definitions where mux_reg can be 0x0. See imx35-pinfunc.h and
> imx25-pinfunc.h:
> 
> 	git grep -E "0x0+ 0x.* 0x.* 0x.* 0x.*"
> 
> This mux_reg behaviour was not described in the DT binding
> documentation. But it is used by some platforms. So even if you change
> the pincfunc headers to use "-1", it would break devicetrees compiled
> with earlier kernel versions.

Ah, sorry, I'm screwed on the previous review.  So we still need the
flag ZERO_OFFSET_VALID to convert invalid 0 mux_reg to -1.

@Adrian,

Will the following change just work for you?

Shawn

diff --git a/drivers/pinctrl/freescale/pinctrl-imx.c b/drivers/pinctrl/freescale/pinctrl-imx.c
index d7b98ba36825..ae801ba7e226 100644
--- a/drivers/pinctrl/freescale/pinctrl-imx.c
+++ b/drivers/pinctrl/freescale/pinctrl-imx.c
@@ -542,6 +542,9 @@ static int imx_pinctrl_parse_groups(struct device_node *np,
                struct imx_pin_reg *pin_reg;
                struct imx_pin *pin = &grp->pins[i];
 
+               if (!(info->flags & ZERO_OFFSET_VALID) && !mux_reg)
+                       mux_reg = -1;
+
                if (info->flags & SHARE_MUX_CONF_REG) {
                        conf_reg = mux_reg;
                } else {
@@ -550,7 +553,7 @@ static int imx_pinctrl_parse_groups(struct device_node *np,
                                conf_reg = -1;
                }
 
-               pin_id = mux_reg ? mux_reg / 4 : conf_reg / 4;
+               pin_id = (mux_reg != -1) ? mux_reg / 4 : conf_reg / 4;
                pin_reg = &info->pin_regs[pin_id];
                pin->pin = pin_id;
                grp->pin_ids[i] = pin_id;