Re: [PATCH] phy: intel: fix enum type mismatch warning

[Dilip Kota]

On 5/28/2020 12:40 AM, Nathan Chancellor wrote:
> On Wed, May 27, 2020 at 03:45:06PM +0200, Arnd Bergmann wrote:
> > clang points out that a local variable is initialized with
> > an enum value of the wrong type:
> >
> > drivers/phy/intel/phy-intel-combo.c:202:34: error: implicit conversion from enumeration type 'enum intel_phy_mode' to different enumeration type 'enum intel_combo_mode' [-Werror,-Wenum-conversion]
> >          enum intel_combo_mode cb_mode = PHY_PCIE_MODE;
> >                                ~~~~~~~   ^~~~~~~~~~~~~
> >
> >  From reading the code, it seems that this was not only the
> > wrong type, but not even supposed to be a code path that can
> > happen in practice.
> >
> > Change the code to have no default phy mode but instead return an
> > error for invalid input.
> >
> > Fixes: ac0a95a3ea78 ("phy: intel: Add driver support for ComboPhy")
> > Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> > ---
> >   drivers/phy/intel/phy-intel-combo.c | 4 +++-
> >   1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/phy/intel/phy-intel-combo.c b/drivers/phy/intel/phy-intel-combo.c
> > index c2a35be4cdfb..04f7b0d08742 100644
> > --- a/drivers/phy/intel/phy-intel-combo.c
> > +++ b/drivers/phy/intel/phy-intel-combo.c
> > @@ -199,7 +199,7 @@ static int intel_cbphy_pcie_dis_pad_refclk(struct intel_cbphy_iphy *iphy)
> >   
> >   static int intel_cbphy_set_mode(struct intel_combo_phy *cbphy)
> >   {
> > -	enum intel_combo_mode cb_mode = PHY_PCIE_MODE;
> > +	enum intel_combo_mode cb_mode;
> >   	enum aggregated_mode aggr = cbphy->aggr_mode;
> >   	struct device *dev = cbphy->dev;
> >   	enum intel_phy_mode mode;
> > @@ -224,6 +224,8 @@ static int intel_cbphy_set_mode(struct intel_combo_phy *cbphy)
> >   
> >   		cb_mode = SATA0_SATA1_MODE;
> >   		break;
> > +	default:
> > +		return -EINVAL;
> >   	}
> >   
> >   	ret = regmap_write(cbphy->hsiocfg, REG_COMBO_MODE(cbphy->bid), cb_mode);
> > --
> > 2.26.2
> I sent an almost identical patch:
>
> https://lore.kernel.org/lkml/20200523035043.3305846-1-natechancellor@xxxxxxxxx/
>
> I left out the default case since clang warns when a switch on an enum
> does not handle all the values (compile time scream) versus a run time
> scream like yours.
>
> I don't have a preference for either so:
>
> Reviewed-by: Nathan Chancellor <natechancellor@xxxxxxxxx>
Thanks for fixing it. I wrongly initiated it with PHY_PCIE_MODE instead 
of PCIE0_PCIE1_MODE to fix the compiler warnings. (On real time use 
case, cb_mode gets initialized with one of the switch case values, it 
never hits the default case, so I didn't add the default case.)

This patch looks good to fix the warnings.
Reviewed-by: Dilip Kota <eswara.kota@xxxxxxxxxxxxxxx>

Regards,
Dilip