[v2,2/2] i2c: mux: pca954x: add property idle-state
diff mbox series

Message ID 20191015044839.23746-2-biwen.li@nxp.com
State Superseded
Headers show
Series
  • [v2,1/2] dt-bindings: i2c: add property idle-state
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Commit Message

Biwen Li Oct. 15, 2019, 4:48 a.m. UTC
This adds property idle-state

Signed-off-by: Biwen Li <biwen.li@nxp.com>
---
Change in v2:
	- update subject and description
	- add property idle-state

 drivers/i2c/muxes/i2c-mux-pca954x.c | 47 ++++++++++++++++++-----------
 1 file changed, 30 insertions(+), 17 deletions(-)

Comments

Peter Rosin Oct. 15, 2019, 1:59 p.m. UTC | #1
On 2019-10-15 06:48, Biwen Li wrote:
> This adds property idle-state
> 
> Signed-off-by: Biwen Li <biwen.li@nxp.com>
> ---
> Change in v2:
> 	- update subject and description
> 	- add property idle-state
> 
>  drivers/i2c/muxes/i2c-mux-pca954x.c | 47 ++++++++++++++++++-----------
>  1 file changed, 30 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c b/drivers/i2c/muxes/i2c-mux-pca954x.c
> index 923aa3a5a3dc..8ec586342b92 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)
> @@ -402,6 +402,25 @@ static void pca954x_cleanup(struct i2c_mux_core *muxc)
>  	i2c_mux_del_adapters(muxc);
>  }
>  
> +static int pca954x_init(struct i2c_client *client, struct pca954x *data)
> +{
> +	/*
> +	 * Write the mux register at addr to verify
> +	 * that the mux is in fact present. This also
> +	 * initializes the mux to disconnected state.
> +	 */

This comment belongs in pca954x_probe, before the call to this function.
However, the comment may now be be wrong since the mux is not always
initialized to the disconnected state.

> +	if (data->idle_state >= 0) {
> +		/* Always enable multiplexer */

While I understand that it is important for your case that the mux is
always enabled, this is just a side effect of having a specific
idle-state. I suggest that you remove this comment.

> +		if (data->chip->muxtype == pca954x_ismux)
> +			data->last_chan = data->idle_state | data->chip->enable;
> +		else
> +			data->last_chan = 1 << data->idle_state;

The meat of this "if" is still duplicated, I was suggesting a helper
that only did the regval calculation so that the new helper could
also be used from pca954x_select_chan.

> +	} else {
> +		/* Disconnect multiplexer */
> +		data->last_chan = 0; /* force the first selection */

These two comments should be combined.

> +	}
> +	return i2c_smbus_write_byte(client, data->last_chan);
> +}
>  /*
>   * I2C init/probing/exit functions
>   */
> @@ -411,7 +430,6 @@ 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 +480,18 @@ static int pca954x_probe(struct i2c_client *client,
>  		}
>  	}
>  
> -	/* 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 (of_property_read_u32(np, "idle-state", &data->idle_state))
> +		data->idle_state = MUX_IDLE_AS_IS;
> +
> +	if (of_property_read_bool(np, "i2c-mux-idle-disconnect"))
> +		data->idle_state = MUX_IDLE_DISCONNECT;

I think you should ignore i2c-mux-idle-disconnect if idle-state is present.
I.e. move this "if" statement into the body of the former "if". Also, you have
broken things if np is NULL.

Cheers,
Peter

> +
> +	ret = pca954x_init(client, data);
> +	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;
>  
>  	ret = pca954x_irq_setup(muxc);
>  	if (ret)
> @@ -531,8 +545,7 @@ 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);
> +	return pca954x_init(client, data);
>  }
>  #endif
>  
>
Biwen Li Oct. 16, 2019, 3:24 a.m. UTC | #2
> 
> On 2019-10-15 06:48, Biwen Li wrote:
> > This adds property idle-state
> >
> > Signed-off-by: Biwen Li <biwen.li@nxp.com>
> > ---
> > Change in v2:
> >       - update subject and description
> >       - add property idle-state
> >
> >  drivers/i2c/muxes/i2c-mux-pca954x.c | 47
> > ++++++++++++++++++-----------
> >  1 file changed, 30 insertions(+), 17 deletions(-)
> >
> > diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c
> > b/drivers/i2c/muxes/i2c-mux-pca954x.c
> > index 923aa3a5a3dc..8ec586342b92 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)
> > @@ -402,6 +402,25 @@ static void pca954x_cleanup(struct
> i2c_mux_core *muxc)
> >       i2c_mux_del_adapters(muxc);
> >  }
> >
> > +static int pca954x_init(struct i2c_client *client, struct pca954x
> > +*data) {
> > +     /*
> > +      * Write the mux register at addr to verify
> > +      * that the mux is in fact present. This also
> > +      * initializes the mux to disconnected state.
> > +      */
> 
> This comment belongs in pca954x_probe, before the call to this function.
> However, the comment may now be be wrong since the mux is not always
> initialized to the disconnected state.
Got it, I will update it in v3.
> 
> > +     if (data->idle_state >= 0) {
> > +             /* Always enable multiplexer */
> 
> While I understand that it is important for your case that the mux is always
> enabled, this is just a side effect of having a specific idle-state. I suggest that
> you remove this comment.
Got it, I will remove it in v3.
> 
> > +             if (data->chip->muxtype == pca954x_ismux)
> > +                     data->last_chan = data->idle_state |
> data->chip->enable;
> > +             else
> > +                     data->last_chan = 1 << data->idle_state;
> 
> The meat of this "if" is still duplicated, I was suggesting a helper that only did
> the regval calculation so that the new helper could also be used from
> pca954x_select_chan.o
> 
> > +     } else {
> > +             /* Disconnect multiplexer */
> > +             data->last_chan = 0; /* force the first selection */
> 
> These two comments should be combined.
Got it.
> 
> > +     }
> > +     return i2c_smbus_write_byte(client, data->last_chan); }
> >  /*
> >   * I2C init/probing/exit functions
> >   */
> > @@ -411,7 +430,6 @@ 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 +480,18 @@ static int pca954x_probe(struct i2c_client
> *client,
> >               }
> >       }
> >
> > -     /* 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 (of_property_read_u32(np, "idle-state", &data->idle_state))
> > +             data->idle_state = MUX_IDLE_AS_IS;
> > +
> > +     if (of_property_read_bool(np, "i2c-mux-idle-disconnect"))
> > +             data->idle_state = MUX_IDLE_DISCONNECT;
> 
> I think you should ignore i2c-mux-idle-disconnect if idle-state is present.
> I.e. move this "if" statement into the body of the former "if". Also, you have
> broken things if np is NULL.
Got it, I will modify it in v3.
> 
> Cheers,
> Peter
> 
> > +
> > +     ret = pca954x_init(client, data);
> > +     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;
> >
> >       ret = pca954x_irq_setup(muxc);
> >       if (ret)
> > @@ -531,8 +545,7 @@ 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);
> > +     return pca954x_init(client, data);
> >  }
> >  #endif
> >
> >

Patch
diff mbox series

diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c b/drivers/i2c/muxes/i2c-mux-pca954x.c
index 923aa3a5a3dc..8ec586342b92 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)
@@ -402,6 +402,25 @@  static void pca954x_cleanup(struct i2c_mux_core *muxc)
 	i2c_mux_del_adapters(muxc);
 }
 
+static int pca954x_init(struct i2c_client *client, struct pca954x *data)
+{
+	/*
+	 * Write the mux register at addr to verify
+	 * that the mux is in fact present. This also
+	 * initializes the mux to disconnected state.
+	 */
+	if (data->idle_state >= 0) {
+		/* Always enable multiplexer */
+		if (data->chip->muxtype == pca954x_ismux)
+			data->last_chan = data->idle_state | data->chip->enable;
+		else
+			data->last_chan = 1 << data->idle_state;
+	} else {
+		/* Disconnect multiplexer */
+		data->last_chan = 0; /* force the first selection */
+	}
+	return i2c_smbus_write_byte(client, data->last_chan);
+}
 /*
  * I2C init/probing/exit functions
  */
@@ -411,7 +430,6 @@  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 +480,18 @@  static int pca954x_probe(struct i2c_client *client,
 		}
 	}
 
-	/* 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 (of_property_read_u32(np, "idle-state", &data->idle_state))
+		data->idle_state = MUX_IDLE_AS_IS;
+
+	if (of_property_read_bool(np, "i2c-mux-idle-disconnect"))
+		data->idle_state = MUX_IDLE_DISCONNECT;
+
+	ret = pca954x_init(client, data);
+	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;
 
 	ret = pca954x_irq_setup(muxc);
 	if (ret)
@@ -531,8 +545,7 @@  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);
+	return pca954x_init(client, data);
 }
 #endif