| Message ID | 20191219033213.30364-3-logan.shaw@alliedtelesis.co.nz (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | hwmon: (adt7475) Added attenuator bypass support | expand |
On 12/18/19 7:32 PM, Logan Shaw wrote: > Added a new file documenting the adt7475 devicetree and added the five > new properties to it. > > Signed-off-by: Logan Shaw <logan.shaw@alliedtelesis.co.nz> > --- > --- > .../devicetree/bindings/hwmon/adt7475.txt | 35 +++++++++++++++++++ > 1 file changed, 35 insertions(+) > create mode 100644 Documentation/devicetree/bindings/hwmon/adt7475.txt > > diff --git a/Documentation/devicetree/bindings/hwmon/adt7475.txt b/Documentation/devicetree/bindings/hwmon/adt7475.txt > new file mode 100644 > index 000000000000..388dd718a246 > --- /dev/null > +++ b/Documentation/devicetree/bindings/hwmon/adt7475.txt > @@ -0,0 +1,35 @@ > +*ADT7475 hwmon sensor. > + > +Required properties: > +- compatible: One of > + "adi,adt7473" > + "adi,adt7475" > + "adi,adt7476" > + "adi,adt7490" > + > +- reg: I2C address > + > +optional properties: > + > +- bypass-attenuator-all: Configures bypassing all voltage input attenuators. > + This is only supported on the ADT7476 and ADT7490, this property does > + nothing on other chips. Both adt7473 and adt7475 do support configuring an attenuator on VCCP > + property present: Bit set to bypass all voltage input attenuators. > + property absent: Registers left unchanged. > + > +- bypass-attenuator-inx: Configures bypassing individual voltage input > + attenuators, where x is an integer from the set {0, 1, 3, 4}. This > + is only supported on the ADT7476 and ADT7490, this property does nothing > + on other chips. > + property present: Bit set to bypass specific voltage input attenuator > + for voltage input x. > + property absent: Registers left unchanged. > + This is interesting. It essentially means "retain configuration from ROM Monitor", but leaves no means to _disable_ the bypass. > +Example: > + > +hwmon@2e { > + compatible = "adi,adt7475"; > + reg = <0x2e>; > + bypass-attenuator-all; > + bypass-attenuator-in1; What would be the purpose of specifying both all and in1 ? > +}; > \ No newline at end of file >
On Wed, 2019-12-18 at 19:53 -0800, Guenter Roeck wrote: > On 12/18/19 7:32 PM, Logan Shaw wrote: > > Added a new file documenting the adt7475 devicetree and added the > > five > > new properties to it. > > > > Signed-off-by: Logan Shaw <logan.shaw@alliedtelesis.co.nz> > > --- > > --- > > .../devicetree/bindings/hwmon/adt7475.txt | 35 > > +++++++++++++++++++ > > 1 file changed, 35 insertions(+) > > create mode 100644 > > Documentation/devicetree/bindings/hwmon/adt7475.txt > > > > diff --git a/Documentation/devicetree/bindings/hwmon/adt7475.txt > > b/Documentation/devicetree/bindings/hwmon/adt7475.txt > > new file mode 100644 > > index 000000000000..388dd718a246 > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/hwmon/adt7475.txt > > @@ -0,0 +1,35 @@ > > +*ADT7475 hwmon sensor. > > + > > +Required properties: > > +- compatible: One of > > + "adi,adt7473" > > + "adi,adt7475" > > + "adi,adt7476" > > + "adi,adt7490" > > + > > +- reg: I2C address > > + > > +optional properties: > > + > > +- bypass-attenuator-all: Configures bypassing all voltage input > > attenuators. > > + This is only supported on the ADT7476 and ADT7490, this > > property does > > + nothing on other chips. > > Both adt7473 and adt7475 do support configuring an attenuator on VCCP > That is true, but as the function of register 0x73 bit 5 differs between the two set of hardware ({adt7473, adt7475} and {adt7476, adt7490}) a solution which allows bypassing VCCP on both gets more complicated which I was trying to avoid. Is it acceptable to split the function load_individual_bypass_attenuators into two, one for each set of chips, and call the appropriate function for the chip? That way adding "bypass-attenuator-in1" to any of the four adt chips DTS will result in the attenuator for VCCP being bypassed (albeit by setting different bits depending on the specific bit). > > + property present: Bit set to bypass all voltage input > > attenuators. > > + property absent: Registers left unchanged. > > + > > +- bypass-attenuator-inx: Configures bypassing individual voltage > > input > > + attenuators, where x is an integer from the set {0, 1, 3, 4}. > > This > > + is only supported on the ADT7476 and ADT7490, this property > > does nothing > > + on other chips. > > + property present: Bit set to bypass specific voltage > > input attenuator > > + for voltage input x. > > + property absent: Registers left unchanged. > > + > > This is interesting. It essentially means "retain configuration from > ROM > Monitor", but leaves no means to _disable_ the bypass. > Only a power cycle (after removing the properties from the DTS) will set the affected bits back to 0. Removing the properties, but only softly restarting the system (no interrupted power supply to the adt chip), will not set the bits back to 0. I decided against setting the bits to 0 by default (if no property was present) as doing so might break compatibility with systems that expect the bits to remain unchanged. A compromise would be to change the "bypass-attenuator-inx" property to "bypass-attenuator-inx = <y>", where y = 1 bypasses the attenuator and y = 0 does not. If the property is not present then the register is left unchanged. It would make sense to do the same to the "bypass- attenuator-all" property. Would these changes be acceptable? > > +Example: > > + > > +hwmon@2e { > > + compatible = "adi,adt7475"; > > + reg = <0x2e>; > > + bypass-attenuator-all; > > + bypass-attenuator-in1; > > What would be the purpose of specifying both all and in1 ? There would be no practical purpose, it was to keep the example compact. Instead "bypass-attenuator-in1" could be removed and added to second device hwmon@2d. This would show off the syntax for each set of properties in a more practical way. > > > +}; > > \ No newline at end of file > > > >
A gentle reminder that this patch exists, as it has (understandably) gone silent over the holiday period. I would appreciate some feedback on my ideas before modifying the patch, so I know I am headed in the right direction. On Wed, 2019-12-18 at 19:53 -0800, Guenter Roeck wrote: > On 12/18/19 7:32 PM, Logan Shaw wrote: > > Added a new file documenting the adt7475 devicetree and added the > > five > > new properties to it. > > > > Signed-off-by: Logan Shaw <logan.shaw@alliedtelesis.co.nz> > > --- > > --- > > .../devicetree/bindings/hwmon/adt7475.txt | 35 > > +++++++++++++++++++ > > 1 file changed, 35 insertions(+) > > create mode 100644 > > Documentation/devicetree/bindings/hwmon/adt7475.txt > > > > diff --git a/Documentation/devicetree/bindings/hwmon/adt7475.txt > > b/Documentation/devicetree/bindings/hwmon/adt7475.txt > > new file mode 100644 > > index 000000000000..388dd718a246 > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/hwmon/adt7475.txt > > @@ -0,0 +1,35 @@ > > +*ADT7475 hwmon sensor. > > + > > +Required properties: > > +- compatible: One of > > + "adi,adt7473" > > + "adi,adt7475" > > + "adi,adt7476" > > + "adi,adt7490" > > + > > +- reg: I2C address > > + > > +optional properties: > > + > > +- bypass-attenuator-all: Configures bypassing all voltage input > > attenuators. > > + This is only supported on the ADT7476 and ADT7490, this > > property does > > + nothing on other chips. > > Both adt7473 and adt7475 do support configuring an attenuator on VCCP > That is true, but as the function of register 0x73 bit 5 differs between the two set of hardware ({adt7473, adt7475} and {adt7476, adt7490}) a solution which allows bypassing VCCP on both gets more complicated which I was trying to avoid. Is it acceptable to split the function load_individual_bypass_attenuators into two, one for each set of chips, and call the appropriate function for the chip? That way adding "bypass-attenuator-in1" to any of the four adt chips DTS will result in the attenuator for VCCP being bypassed (albeit by setting different bits depending on the specific bit). > > + property present: Bit set to bypass all voltage input > > attenuators. > > + property absent: Registers left unchanged. > > + > > +- bypass-attenuator-inx: Configures bypassing individual voltage > > input > > + attenuators, where x is an integer from the set {0, 1, 3, 4}. > > This > > + is only supported on the ADT7476 and ADT7490, this property > > does nothing > > + on other chips. > > + property present: Bit set to bypass specific voltage > > input attenuator > > + for voltage input x. > > + property absent: Registers left unchanged. > > + > > This is interesting. It essentially means "retain configuration from > ROM > Monitor", but leaves no means to _disable_ the bypass. > Only a power cycle (after removing the properties from the DTS) will set the affected bits back to 0. Removing the properties, but only softly restarting the system (no interrupted power supply to the adt chip), will not set the bits back to 0. I decided against setting the bits to 0 by default (if no property was present) as doing so might break compatibility with systems that expect the bits to remain unchanged. A compromise would be to change the "bypass-attenuator-inx" property to "bypass-attenuator-inx = <y>", where y = 1 bypasses the attenuator and y = 0 does not. If the property is not present then the register is left unchanged. It would make sense to do the same to the "bypass- attenuator-all" property. Would these changes be acceptable? > > +Example: > > + > > +hwmon@2e { > > + compatible = "adi,adt7475"; > > + reg = <0x2e>; > > + bypass-attenuator-all; > > + bypass-attenuator-in1; > > What would be the purpose of specifying both all and in1 ? There would be no practical purpose, it was to keep the example compact. Instead "bypass-attenuator-in1" could be removed and added to second device hwmon@2d. This would show off the syntax for each set of properties in a more practical way. > > > +}; > > \ No newline at end of file > > > >
On Fri, Dec 27, 2019 at 02:53:16AM +0000, Logan Shaw wrote: > On Wed, 2019-12-18 at 19:53 -0800, Guenter Roeck wrote: > > On 12/18/19 7:32 PM, Logan Shaw wrote: > > > Added a new file documenting the adt7475 devicetree and added the > > > five > > > new properties to it. > > > > > > Signed-off-by: Logan Shaw <logan.shaw@alliedtelesis.co.nz> > > > --- > > > --- > > > .../devicetree/bindings/hwmon/adt7475.txt | 35 > > > +++++++++++++++++++ > > > 1 file changed, 35 insertions(+) > > > create mode 100644 > > > Documentation/devicetree/bindings/hwmon/adt7475.txt > > > > > > diff --git a/Documentation/devicetree/bindings/hwmon/adt7475.txt > > > b/Documentation/devicetree/bindings/hwmon/adt7475.txt > > > new file mode 100644 > > > index 000000000000..388dd718a246 > > > --- /dev/null > > > +++ b/Documentation/devicetree/bindings/hwmon/adt7475.txt > > > @@ -0,0 +1,35 @@ > > > +*ADT7475 hwmon sensor. > > > + > > > +Required properties: > > > +- compatible: One of > > > + "adi,adt7473" > > > + "adi,adt7475" > > > + "adi,adt7476" > > > + "adi,adt7490" > > > + > > > +- reg: I2C address > > > + > > > +optional properties: > > > + > > > +- bypass-attenuator-all: Configures bypassing all voltage input > > > attenuators. > > > + This is only supported on the ADT7476 and ADT7490, this > > > property does > > > + nothing on other chips. > > > > Both adt7473 and adt7475 do support configuring an attenuator on VCCP > > > > That is true, but as the function of register 0x73 bit 5 differs > between the two set of hardware ({adt7473, adt7475} and {adt7476, > adt7490}) a solution which allows bypassing VCCP on both gets more > complicated which I was trying to avoid. > > Is it acceptable to split the function > load_individual_bypass_attenuators into two, one for each set of > chips, and call the appropriate function for the chip? That way adding > "bypass-attenuator-in1" to any of the four adt chips DTS will result in > the attenuator for VCCP being bypassed (albeit by setting different > bits depending on the specific bit). > You could have per-chip functions, or per-chip mask data in the local data structure. > > > + property present: Bit set to bypass all voltage input > > > attenuators. > > > + property absent: Registers left unchanged. > > > + > > > +- bypass-attenuator-inx: Configures bypassing individual voltage > > > input > > > + attenuators, where x is an integer from the set {0, 1, 3, 4}. > > > This > > > + is only supported on the ADT7476 and ADT7490, this property > > > does nothing > > > + on other chips. > > > + property present: Bit set to bypass specific voltage > > > input attenuator > > > + for voltage input x. > > > + property absent: Registers left unchanged. > > > + > > > > This is interesting. It essentially means "retain configuration from > > ROM > > Monitor", but leaves no means to _disable_ the bypass. > > > > Only a power cycle (after removing the properties from the DTS) will > set the affected bits back to 0. Removing the properties, but only > softly restarting the system (no interrupted power supply to the adt > chip), will not set the bits back to 0. > > I decided against setting the bits to 0 by default (if no property was > present) as doing so might break compatibility with systems that expect > the bits to remain unchanged. > > A compromise would be to change the "bypass-attenuator-inx" property to > "bypass-attenuator-inx = <y>", where y = 1 bypasses the attenuator and > y = 0 does not. If the property is not present then the register is > left unchanged. It would make sense to do the same to the "bypass- > attenuator-all" property. Would these changes be acceptable? > That goes into devicetree object details. Rob might have an opinion on that. > > > +Example: > > > + > > > +hwmon@2e { > > > + compatible = "adi,adt7475"; > > > + reg = <0x2e>; > > > + bypass-attenuator-all; > > > + bypass-attenuator-in1; > > > > What would be the purpose of specifying both all and in1 ? > > There would be no practical purpose, it was to keep the example > compact. Instead "bypass-attenuator-in1" could be removed and added to > second device hwmon@2d. This would show off the syntax for each set of > properties in a more practical way. > That would make more sense. > > > > > +}; > > > \ No newline at end of file Note that you might want to fix that. Guenter
(CC Rob and devicetree) On Wed, 2019-12-18 at 19:53 -0800, Guenter Roeck wrote: > On 12/18/19 7:32 PM, Logan Shaw wrote: > > Added a new file documenting the adt7475 devicetree and added the five > > new properties to it. > > > > Signed-off-by: Logan Shaw <logan.shaw@alliedtelesis.co.nz> > > --- > > --- > > .../devicetree/bindings/hwmon/adt7475.txt | 35 +++++++++++++++++++ > > 1 file changed, 35 insertions(+) > > create mode 100644 Documentation/devicetree/bindings/hwmon/adt7475.txt > > > > diff --git a/Documentation/devicetree/bindings/hwmon/adt7475.txt b/Documentation/devicetree/bindings/hwmon/adt7475.txt > > new file mode 100644 > > index 000000000000..388dd718a246 > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/hwmon/adt7475.txt There's an effort underway to convert the device tree bindings to yaml so it'd be better for new bindings to start off that way. It should be relatively straight forward, there are a couple of existing examples in Documentation/devicetree/bindings/hwmon/ to follow. Also there is an existing entry in Documentation/devicetree/bindings/trivial-devices.yaml for the adt7475 and friends that should be removed as part of the patch that adds the new binding. > > @@ -0,0 +1,35 @@ > > +*ADT7475 hwmon sensor. > > + > > +Required properties: > > +- compatible: One of > > + "adi,adt7473" > > + "adi,adt7475" > > + "adi,adt7476" > > + "adi,adt7490" > > + > > +- reg: I2C address > > + > > +optional properties: > > + > > +- bypass-attenuator-all: Configures bypassing all voltage input attenuators. > > + This is only supported on the ADT7476 and ADT7490, this property does > > + nothing on other chips. I don't know that there's any point in supporting bypass-attenuator-all even though the adt7475 can support it configuring per VIN seems more useful. > > Both adt7473 and adt7475 do support configuring an attenuator on VCCP > > > + property present: Bit set to bypass all voltage input attenuators. > > + property absent: Registers left unchanged. > > + > > +- bypass-attenuator-inx: Configures bypassing individual voltage input > > + attenuators, where x is an integer from the set {0, 1, 3, 4}. This > > + is only supported on the ADT7476 and ADT7490, this property does nothing > > + on other chips. > > + property present: Bit set to bypass specific voltage input attenuator > > + for voltage input x. > > + property absent: Registers left unchanged. > > + > > This is interesting. It essentially means "retain configuration from ROM > Monitor", but leaves no means to _disable_ the bypass. > For our systems Linux is generally the ROM monitor, at least as far as the hwmon devices are concerned. Overriding the HW default makes sense for that case. Do we want the ability to override the configuration from the ROM? It should be easily doable by using an integer property instead of a boolean. > > +Example: > > + > > +hwmon@2e { > > + compatible = "adi,adt7475"; > > + reg = <0x2e>; > > + bypass-attenuator-all; > > + bypass-attenuator-in1; > > What would be the purpose of specifying both all and in1 ? > > > +}; > > \ No newline at end of file > > > >
diff --git a/Documentation/devicetree/bindings/hwmon/adt7475.txt b/Documentation/devicetree/bindings/hwmon/adt7475.txt new file mode 100644 index 000000000000..388dd718a246 --- /dev/null +++ b/Documentation/devicetree/bindings/hwmon/adt7475.txt @@ -0,0 +1,35 @@ +*ADT7475 hwmon sensor. + +Required properties: +- compatible: One of + "adi,adt7473" + "adi,adt7475" + "adi,adt7476" + "adi,adt7490" + +- reg: I2C address + +optional properties: + +- bypass-attenuator-all: Configures bypassing all voltage input attenuators. + This is only supported on the ADT7476 and ADT7490, this property does + nothing on other chips. + property present: Bit set to bypass all voltage input attenuators. + property absent: Registers left unchanged. + +- bypass-attenuator-inx: Configures bypassing individual voltage input + attenuators, where x is an integer from the set {0, 1, 3, 4}. This + is only supported on the ADT7476 and ADT7490, this property does nothing + on other chips. + property present: Bit set to bypass specific voltage input attenuator + for voltage input x. + property absent: Registers left unchanged. + +Example: + +hwmon@2e { + compatible = "adi,adt7475"; + reg = <0x2e>; + bypass-attenuator-all; + bypass-attenuator-in1; +}; \ No newline at end of file
Added a new file documenting the adt7475 devicetree and added the five new properties to it. Signed-off-by: Logan Shaw <logan.shaw@alliedtelesis.co.nz> --- --- .../devicetree/bindings/hwmon/adt7475.txt | 35 +++++++++++++++++++ 1 file changed, 35 insertions(+) create mode 100644 Documentation/devicetree/bindings/hwmon/adt7475.txt