Re: [PATCH v5 3/4] pmbus (core): Add virtual page config bit

[Andrew Jeffery]

On Sun, 2017-11-19 at 08:49 -0800, Guenter Roeck wrote:
> On 11/17/2017 07:26 PM, Andrew Jeffery wrote:
> > Some circumstances call for virtual pages, to expose multiple values
> > packed into an extended PMBus register in a manner non-compliant with
> > the PMBus standard. An example of this is the Maxim MAX31785 controller, 
> > which
> > extends the READ_FAN_SPEED_1 PMBus register from two to four bytes to 
> > support
> > tach readings for both rotors of a dual rotor fan. This extended register
> > contains two word-sized values, one reporting the rate of the fastest rotor,
> > the other the rate of the slowest. The concept of virtual pages aids this
> > situation by mapping the page number onto the value to be selected from the
> > vectored result.
> > 
> > We should not try to set virtual pages on the device as such a page 
> > explicitly
> > doesn't exist; add a flag so we can avoid doing so.
> > 
> > Signed-off-by: Andrew Jeffery 
> > ---
> >   drivers/hwmon/pmbus/pmbus.h  |  2 ++
> >   drivers/hwmon/pmbus/pmbus_core.c | 10 +++---
> >   2 files changed, 9 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h
> > index b54d7604d3ef..d39d506aa63e 100644
> > --- a/drivers/hwmon/pmbus/pmbus.h
> > +++ b/drivers/hwmon/pmbus/pmbus.h
> > @@ -372,6 +372,8 @@ enum pmbus_sensor_classes {
> >   #define PMBUS_HAVE_PWM12  BIT(20)
> >   #define PMBUS_HAVE_PWM34  BIT(21)
> >   
> > +#define PMBUS_PAGE_VIRTUAL BIT(31)
> > +
> >   enum pmbus_data_format { linear = 0, direct, vid };
> >   enum vrm_version { vr11 = 0, vr12, vr13 };
> >   
> > diff --git a/drivers/hwmon/pmbus/pmbus_core.c 
> > b/drivers/hwmon/pmbus/pmbus_core.c
> > index 631db88526b6..ba97230fcde7 100644
> > --- a/drivers/hwmon/pmbus/pmbus_core.c
> > +++ b/drivers/hwmon/pmbus/pmbus_core.c
> > @@ -164,14 +164,18 @@ int pmbus_set_page(struct i2c_client *client, int 
> > page)
> > int rv = 0;
> > int newpage;
> >   
> > -   if (page >= 0 && page != data->currpage) {
> > +   if (page < 0 || page == data->currpage)
> > +   return 0;
> > +
> > +   if (!(data->info->func[page] & PMBUS_PAGE_VIRTUAL)) {
> > rv = i2c_smbus_write_byte_data(client, PMBUS_PAGE, page);
> > newpage = i2c_smbus_read_byte_data(client, PMBUS_PAGE);
> > if (newpage != page)
> > rv = -EIO;
> 
> This should probably be something like
>   rv = i2c_smbus_write_byte_data(client, PMBUS_PAGE, page);
>   if (rv < 0)
>   return rv;
>   newpage = i2c_smbus_read_byte_data(client, PMBUS_PAGE);
>   if (newpage < 0)
>   return newpage;
>   if (newpage != page)
>   return -EIO;
> 
> We can actually drop 'newpage' and just use 'rv'.
> 
> > -   else
> > -   data->currpage = page;
> > }
> > +
> > +   data->currpage = page;
> > +
> 
> ... otherwise currpage is set even on error.

Thanks for catching that, clearly I needed to pay more attention
resolving the conflicts when rebasing on hwmon-next. I'll address all
your points.

Cheers,

Andrew

> 
> > return rv;
> 
> this can then be
>   return 0;
> 
> >   }
> >   EXPORT_SYMBOL_GPL(pmbus_set_page);
> > 
> 
> 

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Re: [PATCH v5 3/4] pmbus (core): Add virtual page config bit

[Guenter Roeck]

On 11/17/2017 07:26 PM, Andrew Jeffery wrote:

Some circumstances call for virtual pages, to expose multiple values
packed into an extended PMBus register in a manner non-compliant with
the PMBus standard. An example of this is the Maxim MAX31785 controller, which
extends the READ_FAN_SPEED_1 PMBus register from two to four bytes to support
tach readings for both rotors of a dual rotor fan. This extended register
contains two word-sized values, one reporting the rate of the fastest rotor,
the other the rate of the slowest. The concept of virtual pages aids this
situation by mapping the page number onto the value to be selected from the
vectored result.

We should not try to set virtual pages on the device as such a page explicitly
doesn't exist; add a flag so we can avoid doing so.

Signed-off-by: Andrew Jeffery 
---
  drivers/hwmon/pmbus/pmbus.h  |  2 ++
  drivers/hwmon/pmbus/pmbus_core.c | 10 +++---
  2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h
index b54d7604d3ef..d39d506aa63e 100644
--- a/drivers/hwmon/pmbus/pmbus.h
+++ b/drivers/hwmon/pmbus/pmbus.h
@@ -372,6 +372,8 @@ enum pmbus_sensor_classes {
  #define PMBUS_HAVE_PWM12  BIT(20)
  #define PMBUS_HAVE_PWM34  BIT(21)
  
+#define PMBUS_PAGE_VIRTUAL	BIT(31)

+
  enum pmbus_data_format { linear = 0, direct, vid };
  enum vrm_version { vr11 = 0, vr12, vr13 };
  
diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c

index 631db88526b6..ba97230fcde7 100644
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/drivers/hwmon/pmbus/pmbus_core.c
@@ -164,14 +164,18 @@ int pmbus_set_page(struct i2c_client *client, int page)
int rv = 0;
int newpage;
  
-	if (page >= 0 && page != data->currpage) {

+   if (page < 0 || page == data->currpage)
+   return 0;
+
+   if (!(data->info->func[page] & PMBUS_PAGE_VIRTUAL)) {
rv = i2c_smbus_write_byte_data(client, PMBUS_PAGE, page);
newpage = i2c_smbus_read_byte_data(client, PMBUS_PAGE);
if (newpage != page)
rv = -EIO;


This should probably be something like
rv = i2c_smbus_write_byte_data(client, PMBUS_PAGE, page);
if (rv < 0)
return rv;
newpage = i2c_smbus_read_byte_data(client, PMBUS_PAGE);
if (newpage < 0)
return newpage;
if (newpage != page)
return -EIO;

We can actually drop 'newpage' and just use 'rv'.


-   else
-   data->currpage = page;
}
+
+   data->currpage = page;
+


... otherwise currpage is set even on error.


return rv;


this can then be
return 0;


  }
  EXPORT_SYMBOL_GPL(pmbus_set_page);



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[PATCH v5 3/4] pmbus (core): Add virtual page config bit

[Andrew Jeffery]

Some circumstances call for virtual pages, to expose multiple values
packed into an extended PMBus register in a manner non-compliant with
the PMBus standard. An example of this is the Maxim MAX31785 controller, which
extends the READ_FAN_SPEED_1 PMBus register from two to four bytes to support
tach readings for both rotors of a dual rotor fan. This extended register
contains two word-sized values, one reporting the rate of the fastest rotor,
the other the rate of the slowest. The concept of virtual pages aids this
situation by mapping the page number onto the value to be selected from the
vectored result.

We should not try to set virtual pages on the device as such a page explicitly
doesn't exist; add a flag so we can avoid doing so.

Signed-off-by: Andrew Jeffery 
---
 drivers/hwmon/pmbus/pmbus.h  |  2 ++
 drivers/hwmon/pmbus/pmbus_core.c | 10 +++---
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h
index b54d7604d3ef..d39d506aa63e 100644
--- a/drivers/hwmon/pmbus/pmbus.h
+++ b/drivers/hwmon/pmbus/pmbus.h
@@ -372,6 +372,8 @@ enum pmbus_sensor_classes {
 #define PMBUS_HAVE_PWM12   BIT(20)
 #define PMBUS_HAVE_PWM34   BIT(21)
 
+#define PMBUS_PAGE_VIRTUAL BIT(31)
+
 enum pmbus_data_format { linear = 0, direct, vid };
 enum vrm_version { vr11 = 0, vr12, vr13 };
 
diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
index 631db88526b6..ba97230fcde7 100644
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/drivers/hwmon/pmbus/pmbus_core.c
@@ -164,14 +164,18 @@ int pmbus_set_page(struct i2c_client *client, int page)
int rv = 0;
int newpage;
 
-   if (page >= 0 && page != data->currpage) {
+   if (page < 0 || page == data->currpage)
+   return 0;
+
+   if (!(data->info->func[page] & PMBUS_PAGE_VIRTUAL)) {
rv = i2c_smbus_write_byte_data(client, PMBUS_PAGE, page);
newpage = i2c_smbus_read_byte_data(client, PMBUS_PAGE);
if (newpage != page)
rv = -EIO;
-   else
-   data->currpage = page;
}
+
+   data->currpage = page;
+
return rv;
 }
 EXPORT_SYMBOL_GPL(pmbus_set_page);
-- 
git-series 0.9.1
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