RE: [EXT] Re: [PATCH 2/2] i2c: mux: pca954x: replace property i2c-mux-idle-disconnect

[Biwen Li]

> 
> Caution: EXT Email
> 
> On 2019-10-14 13:25, Biwen Li wrote:
> > This replaces property i2c-mux-idle-disconnect with idle-state
> >
> > Signed-off-by: Biwen Li <biwen.li@xxxxxxx>
> > ---
> >  drivers/i2c/muxes/i2c-mux-pca954x.c | 44
> > ++++++++++++++++++++---------
> >  1 file changed, 31 insertions(+), 13 deletions(-)
> >
> > diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c
> > b/drivers/i2c/muxes/i2c-mux-pca954x.c
> > index 923aa3a5a3dc..a330929c4d67 100644
> > --- a/drivers/i2c/muxes/i2c-mux-pca954x.c
> > +++ b/drivers/i2c/muxes/i2c-mux-pca954x.c
> > @@ -86,7 +86,7 @@ struct pca954x {
> >
> >       u8 last_chan;           /* last register value */
> >       /* MUX_IDLE_AS_IS, MUX_IDLE_DISCONNECT or >= 0 for channel */
> > -     s8 idle_state;
> > +     s32 idle_state;
> >
> >       struct i2c_client *client;
> >
> > @@ -256,7 +256,7 @@ static int pca954x_deselect_mux(struct
> > i2c_mux_core *muxc, u32 chan)  {
> >       struct pca954x *data = i2c_mux_priv(muxc);
> >       struct i2c_client *client = data->client;
> > -     s8 idle_state;
> > +     s32 idle_state;
> >
> >       idle_state = READ_ONCE(data->idle_state);
> >       if (idle_state >= 0)
> > @@ -411,7 +411,6 @@ static int pca954x_probe(struct i2c_client *client,
> >       struct i2c_adapter *adap = client->adapter;
> >       struct device *dev = &client->dev;
> >       struct device_node *np = dev->of_node;
> > -     bool idle_disconnect_dt;
> >       struct gpio_desc *gpio;
> >       struct i2c_mux_core *muxc;
> >       struct pca954x *data;
> > @@ -462,22 +461,31 @@ static int pca954x_probe(struct i2c_client
> *client,
> >               }
> >       }
> >
> > +     if (of_property_read_u32(np, "idle-state", &data->idle_state))
> > +             data->idle_state = MUX_IDLE_AS_IS;
> > +
> >       /* Write the mux register at addr to verify
> >        * that the mux is in fact present. This also
> >        * initializes the mux to disconnected state.
> >        */
> > -     if (i2c_smbus_write_byte(client, 0) < 0) {
> > +     if (data->idle_state >= 0){
> 
> Space before {
Okay, got it, I will add it in v2.
> 
> > +             data->last_chan = data->idle_state;
> 
> data->last_chan should have the actual register value, i.e. (untested)
Okay, got it, I will adjust it in v2.
> 
>                 if (data->chip->muxtype == pca954x_ismux)
>                         data->last_chan = data->idle_state |
> data->chip->enable;
>                 else
>                         data->last_chan = 1 << data->idle_state;
> 
>                 ret = i2c_smbus_write_byte(client, data->last_chan);
> 
> But since this regval calculation is now needed in three places, it should be
> moved to a helper function.
You are right, I will add a helper function in v2.
> 
> > +             /* Always enable multiplexer */
> > +             ret = i2c_smbus_write_byte(client, data->last_chan |
> > +                             (data->chip->muxtype ==
> pca954x_ismux ?
> > +                              data->chip->enable : 0));
> > +     }
> > +     else{
> 
> Space before {
Got it, I will add it in v2.
> 
> Naturally, you have the exact same issues in the pca954x_resume hunk,
> below.
Got it
> 
> > +             data->last_chan = 0;               /* force the first
> selection */
> > +             /* Disconnect multiplexer */
> > +             ret = i2c_smbus_write_byte(client, data->last_chan);
> > +     }
> > +
> > +     if (ret < 0) {
> >               dev_warn(dev, "probe failed\n");
> >               return -ENODEV;
> >       }
> >
> > -     data->last_chan = 0;               /* force the first selection */
> > -     data->idle_state = MUX_IDLE_AS_IS;
> > -
> > -     idle_disconnect_dt = np &&
> > -             of_property_read_bool(np, "i2c-mux-idle-disconnect");
> > -     if (idle_disconnect_dt)
> > -             data->idle_state = MUX_IDLE_DISCONNECT;
> 
> In case the idle-state property is missing, you need to fall back to the old
> behavior and handle i2c-mux-idle-disconnect as before.
Okay, got it, I will add it in v2.
> 
> Cheers,
> Peter
> 
> >
> >       ret = pca954x_irq_setup(muxc);
> >       if (ret)
> > @@ -531,8 +539,18 @@ static int pca954x_resume(struct device *dev)
> >       struct i2c_mux_core *muxc = i2c_get_clientdata(client);
> >       struct pca954x *data = i2c_mux_priv(muxc);
> >
> > -     data->last_chan = 0;
> > -     return i2c_smbus_write_byte(client, 0);
> > +     if (data->idle_state >= 0){
> > +             data->last_chan = data->idle_state;
> > +             /* Always enable multiplexer */
> > +             return i2c_smbus_write_byte(client, data->last_chan |
> > +                             (data->chip->muxtype ==
> pca954x_ismux ?
> > +                              data->chip->enable : 0));
> > +     }
> > +     else{
> > +             data->last_chan = 0;
> > +             /* Disconnect multiplexer */
> > +             return i2c_smbus_write_byte(client, data->last_chan);
> > +     }
> >  }
> >  #endif
> >
> >