| Message ID | 20250225-upstream-lt3074-v2-1-18ad10ba542e@analog.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Add support for LT3074 low voltage linear regulator | expand |
On Tue, Feb 25, 2025 at 09:01:13PM +0800, Cedric Encarnacion wrote: > Add Analog Devices LT3074 Ultralow Noise, High PSRR Dropout Linear > Regulator. > > Signed-off-by: Cedric Encarnacion <cedricjustine.encarnacion@analog.com> > --- > .../bindings/hwmon/pmbus/adi,lt3074.yaml | 64 ++++++++++++++++++++++ > MAINTAINERS | 7 +++ > 2 files changed, 71 insertions(+) > > diff --git a/Documentation/devicetree/bindings/hwmon/pmbus/adi,lt3074.yaml b/Documentation/devicetree/bindings/hwmon/pmbus/adi,lt3074.yaml > new file mode 100644 > index 0000000000000000000000000000000000000000..714426fd655a8daa96e15e1f789743f36001ac7a > --- /dev/null > +++ b/Documentation/devicetree/bindings/hwmon/pmbus/adi,lt3074.yaml > @@ -0,0 +1,64 @@ > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) > +%YAML 1.2 > +--- > +$id: http://devicetree.org/schemas/hwmon/pmbus/adi,lt3074.yaml# > +$schema: http://devicetree.org/meta-schemas/core.yaml# > + > +title: Analog Devices LT3074 voltage regulator > + > +maintainers: > + - Cedric Encarnacion <cedricjustine.encarnacion@analog.com> > + > +description: | > + The LT3074 is a low voltage, ultra-low noise and ultra-fast transient > + response linear regulator. It allows telemetry for input/output voltage, > + output current and temperature through the PMBus serial interface. > + > + Datasheet: > + https://www.analog.com/en/products/lt3074.html > + > +properties: > + compatible: > + enum: > + - adi,lt3074 > + > + reg: > + maxItems: 1 > + > + regulators: > + type: object > + description: | > + list of regulators provided by this controller. You have only one regulator, so drop the "regulators". vout could be here, but since you do not have any other resources, I doubt it stands on its own either. This is even visible in your DTS - you named the device as regulator, so logically this is the regulator. Regulator does not have regulators (otherwise they could also have regulators... so triple regulator). hwmon code might need some changes, but that's not really relevant for proper hardware description. Best regards, Krzysztof
On Wed, Feb 26, 2025 at 09:20:40AM +0100, Krzysztof Kozlowski wrote: > On Tue, Feb 25, 2025 at 09:01:13PM +0800, Cedric Encarnacion wrote: > > Add Analog Devices LT3074 Ultralow Noise, High PSRR Dropout Linear > > Regulator. > > > > Signed-off-by: Cedric Encarnacion <cedricjustine.encarnacion@analog.com> > > --- > > .../bindings/hwmon/pmbus/adi,lt3074.yaml | 64 ++++++++++++++++++++++ > > MAINTAINERS | 7 +++ > > 2 files changed, 71 insertions(+) > > > > diff --git a/Documentation/devicetree/bindings/hwmon/pmbus/adi,lt3074.yaml b/Documentation/devicetree/bindings/hwmon/pmbus/adi,lt3074.yaml > > new file mode 100644 > > index 0000000000000000000000000000000000000000..714426fd655a8daa96e15e1f789743f36001ac7a > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/hwmon/pmbus/adi,lt3074.yaml > > @@ -0,0 +1,64 @@ > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) > > +%YAML 1.2 > > +--- > > +$id: http://devicetree.org/schemas/hwmon/pmbus/adi,lt3074.yaml# > > +$schema: http://devicetree.org/meta-schemas/core.yaml# > > + > > +title: Analog Devices LT3074 voltage regulator > > + > > +maintainers: > > + - Cedric Encarnacion <cedricjustine.encarnacion@analog.com> > > + > > +description: | > > + The LT3074 is a low voltage, ultra-low noise and ultra-fast transient > > + response linear regulator. It allows telemetry for input/output voltage, > > + output current and temperature through the PMBus serial interface. > > + > > + Datasheet: > > + https://www.analog.com/en/products/lt3074.html > > + > > +properties: > > + compatible: > > + enum: > > + - adi,lt3074 > > + > > + reg: > > + maxItems: 1 > > + > > + regulators: > > + type: object > > + description: | > > + list of regulators provided by this controller. > > You have only one regulator, so drop the "regulators". vout could be > here, but since you do not have any other resources, I doubt it stands > on its own either. This is even visible in your DTS - you named the > device as regulator, so logically this is the regulator. Regulator does > not have regulators (otherwise they could also have regulators... so > triple regulator). > > hwmon code might need some changes, but that's not really relevant for > proper hardware description. Normally, I would agree, but it seems generic pmbus code expects this structure. This just came up with changing another binding maintained by 'Not Me' to follow this structure. We're stuck with the existing way, so I don't know that it is worth supporting 2 ways forever. OTOH, is it guaranteed that these devices will only ever be pmbus devices or that other regulator devices which are not handled as pmbus devices currently will be in the future. If so, more flexibility in the bindings will be needed. Rob
On 2/26/25 06:59, Rob Herring wrote: > On Wed, Feb 26, 2025 at 09:20:40AM +0100, Krzysztof Kozlowski wrote: >> On Tue, Feb 25, 2025 at 09:01:13PM +0800, Cedric Encarnacion wrote: >>> Add Analog Devices LT3074 Ultralow Noise, High PSRR Dropout Linear >>> Regulator. >>> >>> Signed-off-by: Cedric Encarnacion <cedricjustine.encarnacion@analog.com> >>> --- >>> .../bindings/hwmon/pmbus/adi,lt3074.yaml | 64 ++++++++++++++++++++++ >>> MAINTAINERS | 7 +++ >>> 2 files changed, 71 insertions(+) >>> >>> diff --git a/Documentation/devicetree/bindings/hwmon/pmbus/adi,lt3074.yaml b/Documentation/devicetree/bindings/hwmon/pmbus/adi,lt3074.yaml >>> new file mode 100644 >>> index 0000000000000000000000000000000000000000..714426fd655a8daa96e15e1f789743f36001ac7a >>> --- /dev/null >>> +++ b/Documentation/devicetree/bindings/hwmon/pmbus/adi,lt3074.yaml >>> @@ -0,0 +1,64 @@ >>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) >>> +%YAML 1.2 >>> +--- >>> +$id: http://devicetree.org/schemas/hwmon/pmbus/adi,lt3074.yaml# >>> +$schema: http://devicetree.org/meta-schemas/core.yaml# >>> + >>> +title: Analog Devices LT3074 voltage regulator >>> + >>> +maintainers: >>> + - Cedric Encarnacion <cedricjustine.encarnacion@analog.com> >>> + >>> +description: | >>> + The LT3074 is a low voltage, ultra-low noise and ultra-fast transient >>> + response linear regulator. It allows telemetry for input/output voltage, >>> + output current and temperature through the PMBus serial interface. >>> + >>> + Datasheet: >>> + https://www.analog.com/en/products/lt3074.html >>> + >>> +properties: >>> + compatible: >>> + enum: >>> + - adi,lt3074 >>> + >>> + reg: >>> + maxItems: 1 >>> + >>> + regulators: >>> + type: object >>> + description: | >>> + list of regulators provided by this controller. >> >> You have only one regulator, so drop the "regulators". vout could be >> here, but since you do not have any other resources, I doubt it stands >> on its own either. This is even visible in your DTS - you named the >> device as regulator, so logically this is the regulator. Regulator does >> not have regulators (otherwise they could also have regulators... so >> triple regulator). >> >> hwmon code might need some changes, but that's not really relevant for >> proper hardware description. > > Normally, I would agree, but it seems generic pmbus code expects this > structure. This just came up with changing another binding maintained by > 'Not Me' to follow this structure. We're stuck with the existing way, so > I don't know that it is worth supporting 2 ways forever. OTOH, is it > guaranteed that these devices will only ever be pmbus devices or that > other regulator devices which are not handled as pmbus devices currently > will be in the future. If so, more flexibility in the bindings will be > needed. > I would appreciate if someone would explain to me what the problems with the current PMBus code actually are. I have seen several comments claiming that the code should be changed, but I have no idea what the expected changes actually are or, in other words, what the PMBus code should be doing differently. Thanks, Guenter
On Wed, Feb 26, 2025 at 11:17:48AM -0800, Guenter Roeck wrote: > On 2/26/25 06:59, Rob Herring wrote: > > On Wed, Feb 26, 2025 at 09:20:40AM +0100, Krzysztof Kozlowski wrote: > > > On Tue, Feb 25, 2025 at 09:01:13PM +0800, Cedric Encarnacion wrote: > > > > Add Analog Devices LT3074 Ultralow Noise, High PSRR Dropout Linear > > > > Regulator. > > > > > > > > Signed-off-by: Cedric Encarnacion <cedricjustine.encarnacion@analog.com> > > > > --- > > > > .../bindings/hwmon/pmbus/adi,lt3074.yaml | 64 ++++++++++++++++++++++ > > > > MAINTAINERS | 7 +++ > > > > 2 files changed, 71 insertions(+) > > > > > > > > diff --git a/Documentation/devicetree/bindings/hwmon/pmbus/adi,lt3074.yaml b/Documentation/devicetree/bindings/hwmon/pmbus/adi,lt3074.yaml > > > > new file mode 100644 > > > > index 0000000000000000000000000000000000000000..714426fd655a8daa96e15e1f789743f36001ac7a > > > > --- /dev/null > > > > +++ b/Documentation/devicetree/bindings/hwmon/pmbus/adi,lt3074.yaml > > > > @@ -0,0 +1,64 @@ > > > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) > > > > +%YAML 1.2 > > > > +--- > > > > +$id: http://devicetree.org/schemas/hwmon/pmbus/adi,lt3074.yaml# > > > > +$schema: http://devicetree.org/meta-schemas/core.yaml# > > > > + > > > > +title: Analog Devices LT3074 voltage regulator > > > > + > > > > +maintainers: > > > > + - Cedric Encarnacion <cedricjustine.encarnacion@analog.com> > > > > + > > > > +description: | > > > > + The LT3074 is a low voltage, ultra-low noise and ultra-fast transient > > > > + response linear regulator. It allows telemetry for input/output voltage, > > > > + output current and temperature through the PMBus serial interface. > > > > + > > > > + Datasheet: > > > > + https://www.analog.com/en/products/lt3074.html > > > > + > > > > +properties: > > > > + compatible: > > > > + enum: > > > > + - adi,lt3074 > > > > + > > > > + reg: > > > > + maxItems: 1 > > > > + > > > > + regulators: > > > > + type: object > > > > + description: | > > > > + list of regulators provided by this controller. > > > > > > You have only one regulator, so drop the "regulators". vout could be > > > here, but since you do not have any other resources, I doubt it stands > > > on its own either. This is even visible in your DTS - you named the > > > device as regulator, so logically this is the regulator. Regulator does > > > not have regulators (otherwise they could also have regulators... so > > > triple regulator). > > > > > > hwmon code might need some changes, but that's not really relevant for > > > proper hardware description. > > > > Normally, I would agree, but it seems generic pmbus code expects this > > structure. This just came up with changing another binding maintained by > > 'Not Me' to follow this structure. We're stuck with the existing way, so > > I don't know that it is worth supporting 2 ways forever. OTOH, is it > > guaranteed that these devices will only ever be pmbus devices or that > > other regulator devices which are not handled as pmbus devices currently > > will be in the future. If so, more flexibility in the bindings will be > > needed. > > > > I would appreciate if someone would explain to me what the problems with > the current PMBus code actually are. I have seen several comments claiming Not exactly a problem but missing feature. pmbus code (at least one of macros I looked at) expects regulator node and some sort of child of it (vout), while such simple devices should be: regulator { compatible = "adi,lt3074"; regulator-name = "vout"; regulator-min-microvolt = "100000"; regulator-max-microvolt = "100000"; }; so without any of regulators and regulators/vout subnodes. > that the code should be changed, but I have no idea what the expected changes > actually are or, in other words, what the PMBus code should be doing > differently. I did not investigate much into pmbus code, but this might be as simple as accepting arguments for .of_match and .regulators_node and then accepting NULLs as them as well. Or a new macro which assigns NULLs there. Regulator core handles .regulators_node=NULL already. Best regards, Krzysztof
On Thu, Feb 27, 2025 at 09:50:23AM +0100, Krzysztof Kozlowski wrote: > > > > > > > > hwmon code might need some changes, but that's not really relevant for > > > > proper hardware description. > > > > > > Normally, I would agree, but it seems generic pmbus code expects this > > > structure. This just came up with changing another binding maintained by > > > 'Not Me' to follow this structure. We're stuck with the existing way, so > > > I don't know that it is worth supporting 2 ways forever. OTOH, is it > > > guaranteed that these devices will only ever be pmbus devices or that > > > other regulator devices which are not handled as pmbus devices currently > > > will be in the future. If so, more flexibility in the bindings will be > > > needed. > > > > > > > I would appreciate if someone would explain to me what the problems with > > the current PMBus code actually are. I have seen several comments claiming > > Not exactly a problem but missing feature. pmbus code (at least one of > macros I looked at) expects regulator node and some sort of child of it > (vout), while such simple devices should be: > > regulator { > compatible = "adi,lt3074"; > regulator-name = "vout"; > regulator-min-microvolt = "100000"; > regulator-max-microvolt = "100000"; > }; > > so without any of regulators and regulators/vout subnodes. > > > that the code should be changed, but I have no idea what the expected changes > > actually are or, in other words, what the PMBus code should be doing > > differently. > > I did not investigate much into pmbus code, but this might be as simple > as accepting arguments for .of_match and .regulators_node and then > accepting NULLs as them as well. Or a new macro which assigns NULLs > there. > Unless I am missing something, the following should do the trick. diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h index ddb19c9726d6..289767e5d599 100644 --- a/drivers/hwmon/pmbus/pmbus.h +++ b/drivers/hwmon/pmbus/pmbus.h @@ -512,7 +512,6 @@ int pmbus_regulator_init_cb(struct regulator_dev *rdev, { \ .name = (_name), \ .of_match = of_match_ptr(_name), \ - .regulators_node = of_match_ptr("regulators"), \ .ops = &pmbus_regulator_ops, \ .type = REGULATOR_VOLTAGE, \ .owner = THIS_MODULE, \ Maybe someone can check if that works. Thanks, Guenter
diff --git a/Documentation/devicetree/bindings/hwmon/pmbus/adi,lt3074.yaml b/Documentation/devicetree/bindings/hwmon/pmbus/adi,lt3074.yaml new file mode 100644 index 0000000000000000000000000000000000000000..714426fd655a8daa96e15e1f789743f36001ac7a --- /dev/null +++ b/Documentation/devicetree/bindings/hwmon/pmbus/adi,lt3074.yaml @@ -0,0 +1,64 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/hwmon/pmbus/adi,lt3074.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Analog Devices LT3074 voltage regulator + +maintainers: + - Cedric Encarnacion <cedricjustine.encarnacion@analog.com> + +description: | + The LT3074 is a low voltage, ultra-low noise and ultra-fast transient + response linear regulator. It allows telemetry for input/output voltage, + output current and temperature through the PMBus serial interface. + + Datasheet: + https://www.analog.com/en/products/lt3074.html + +properties: + compatible: + enum: + - adi,lt3074 + + reg: + maxItems: 1 + + regulators: + type: object + description: | + list of regulators provided by this controller. + + properties: + vout: + $ref: /schemas/regulator/regulator.yaml# + type: object + + unevaluatedProperties: false + + additionalProperties: false + +required: + - compatible + - reg + +additionalProperties: false + +examples: + - | + i2c { + #address-cells = <1>; + #size-cells = <0>; + + regulator@6d { + compatible = "adi,lt3074"; + reg = <0x6d>; + + regulators { + vcc_1v2: vout { + regulator-name = "VCC_1V2"; + }; + }; + }; + }; diff --git a/MAINTAINERS b/MAINTAINERS index 896a307fa06545e2861abe46ea7029f9b4d3628e..4a59ee6a03919af6a48717a0ddddabc7241a9e63 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -13687,6 +13687,13 @@ L: linux-scsi@vger.kernel.org S: Maintained F: drivers/scsi/sym53c8xx_2/ +LT3074 HARDWARE MONITOR DRIVER +M: Cedric Encarnacion <cedricjustine.encarnacion@analog.com> +L: linux-hwmon@vger.kernel.org +S: Supported +W: https://ez.analog.com/linux-software-drivers +F: Documentation/devicetree/bindings/hwmon/pmbus/adi,lt3074.yaml + LTC1660 DAC DRIVER M: Marcus Folkesson <marcus.folkesson@gmail.com> L: linux-iio@vger.kernel.org
Add Analog Devices LT3074 Ultralow Noise, High PSRR Dropout Linear Regulator. Signed-off-by: Cedric Encarnacion <cedricjustine.encarnacion@analog.com> --- .../bindings/hwmon/pmbus/adi,lt3074.yaml | 64 ++++++++++++++++++++++ MAINTAINERS | 7 +++ 2 files changed, 71 insertions(+)