[PATCH v2 0/3] hwmon: (lm75) Add regulator support

[PATCH v2 0/3] hwmon: (lm75) Add regulator support

[Alban Bedel]

Hi everybody,

this small series add regulator support to the lm75 driver for boards
that don't always power such a sensor. While at it also convert the
DT bindings to yaml.

v2: - Fixed the DT example while converting to YAML
    - Removed the unneeded maxItems from the binding documentation
    - Use dummy regulator insted of explicitly handling missing regulator

Alban Bedel (3):
  dt-bindings: hwmon: Convert lm75 bindings to yaml
  dt-bindings: hwmon: Add the +vs supply to the lm75 bindings
  hwmon: (lm75) Add regulator support

 .../devicetree/bindings/hwmon/lm75.txt        | 39 -----------
 .../devicetree/bindings/hwmon/lm75.yaml       | 64 +++++++++++++++++++
 drivers/hwmon/lm75.c                          | 23 ++++++-
 3 files changed, 85 insertions(+), 41 deletions(-)
 delete mode 100644 Documentation/devicetree/bindings/hwmon/lm75.txt
 create mode 100644 Documentation/devicetree/bindings/hwmon/lm75.yaml

-- 
2.25.1

[PATCH v2 1/3] dt-bindings: hwmon: Convert lm75 bindings to yaml

[Alban Bedel]

In order to automate the verification of DT nodes convert lm75.txt to
lm75.yaml.

Signed-off-by: Alban Bedel <alban.bedel@aerq.com>
---
v2: Fix the example to pass `make dt_binding_check`
---
 .../devicetree/bindings/hwmon/lm75.txt        | 39 ------------
 .../devicetree/bindings/hwmon/lm75.yaml       | 60 +++++++++++++++++++
 2 files changed, 60 insertions(+), 39 deletions(-)
 delete mode 100644 Documentation/devicetree/bindings/hwmon/lm75.txt
 create mode 100644 Documentation/devicetree/bindings/hwmon/lm75.yaml

diff --git a/Documentation/devicetree/bindings/hwmon/lm75.txt b/Documentation/devicetree/bindings/hwmon/lm75.txt
deleted file mode 100644
index 273616702c51..000000000000
--- a/Documentation/devicetree/bindings/hwmon/lm75.txt
+++ /dev/null
@@ -1,39 +0,0 @@
-*LM75 hwmon sensor.
-
-Required properties:
-- compatible: manufacturer and chip name, one of
-		"adi,adt75",
-		"dallas,ds1775",
-		"dallas,ds75",
-		"dallas,ds7505",
-		"gmt,g751",
-		"national,lm75",
-		"national,lm75a",
-		"national,lm75b",
-		"maxim,max6625",
-		"maxim,max6626",
-		"maxim,max31725",
-		"maxim,max31726",
-		"maxim,mcp980x",
-		"nxp,pct2075",
-		"st,stds75",
-		"st,stlm75",
-		"microchip,tcn75",
-		"ti,tmp100",
-		"ti,tmp101",
-		"ti,tmp105",
-		"ti,tmp112",
-		"ti,tmp175",
-		"ti,tmp275",
-		"ti,tmp75",
-		"ti,tmp75b",
-		"ti,tmp75c",
-
-- reg: I2C bus address of the device
-
-Example:
-
-sensor@48 {
-	compatible = "st,stlm75";
-	reg = <0x48>;
-};
diff --git a/Documentation/devicetree/bindings/hwmon/lm75.yaml b/Documentation/devicetree/bindings/hwmon/lm75.yaml
new file mode 100644
index 000000000000..203829c6ba6f
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwmon/lm75.yaml
@@ -0,0 +1,60 @@
+# SPDX-License-Identifier: GPL-2.0-only or BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/hwmon/lm75.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: LM75 hwmon sensor
+
+maintainers:
+  - Jean Delvare <jdelvare@suse.com>
+  - Guenter Roeck <linux@roeck-us.net>
+
+properties:
+  compatible:
+    enum:
+      - adi,adt75
+      - dallas,ds1775
+      - dallas,ds75
+      - dallas,ds7505
+      - gmt,g751
+      - national,lm75
+      - national,lm75a
+      - national,lm75b
+      - maxim,max6625
+      - maxim,max6626
+      - maxim,max31725
+      - maxim,max31726
+      - maxim,mcp980x
+      - nxp,pct2075
+      - st,stds75
+      - st,stlm75
+      - microchip,tcn75
+      - ti,tmp100
+      - ti,tmp101
+      - ti,tmp105
+      - ti,tmp112
+      - ti,tmp175
+      - ti,tmp275
+      - ti,tmp75
+      - ti,tmp75b
+      - ti,tmp75c
+
+  reg:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+
+examples:
+  - |
+    i2c {
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      sensor@48 {
+        compatible = "st,stlm75";
+        reg = <0x48>;
+      };
+    };
-- 
2.25.1

[PATCH v2 2/3] dt-bindings: hwmon: Add the +vs supply to the lm75 bindings

[Alban Bedel]

Some boards might have a regulator that control the +VS supply, add it
to the bindings.

Signed-off-by: Alban Bedel <alban.bedel@aerq.com>
---
v2: Removed the unneeded `maxItems` attribute
---
 Documentation/devicetree/bindings/hwmon/lm75.yaml | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Documentation/devicetree/bindings/hwmon/lm75.yaml b/Documentation/devicetree/bindings/hwmon/lm75.yaml
index 203829c6ba6f..1c1ce4cf1616 100644
--- a/Documentation/devicetree/bindings/hwmon/lm75.yaml
+++ b/Documentation/devicetree/bindings/hwmon/lm75.yaml
@@ -43,6 +43,9 @@ properties:
   reg:
     maxItems: 1
 
+  vs-supply:
+    description: phandle to the regulator that provides the +VS supply
+
 required:
   - compatible
   - reg
@@ -56,5 +59,6 @@ examples:
       sensor@48 {
         compatible = "st,stlm75";
         reg = <0x48>;
+        vs-supply = <&vs>;
       };
     };
-- 
2.25.1

[PATCH v2 3/3] hwmon: (lm75) Add regulator support

[Alban Bedel]

Add regulator support for boards where the sensor first need to be
powered up before it can be used.

Signed-off-by: Alban Bedel <alban.bedel@aerq.com>
---
v2: Rely on dummy regulators instead of explicitly handling missing
    regulator
---
 drivers/hwmon/lm75.c | 23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c
index ba0be48aeadd..e394df648c26 100644
--- a/drivers/hwmon/lm75.c
+++ b/drivers/hwmon/lm75.c
@@ -17,6 +17,7 @@
 #include <linux/of.h>
 #include <linux/regmap.h>
 #include <linux/util_macros.h>
+#include <linux/regulator/consumer.h>
 #include "lm75.h"
 
 /*
@@ -101,6 +102,7 @@ static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
 struct lm75_data {
 	struct i2c_client		*client;
 	struct regmap			*regmap;
+	struct regulator		*vs;
 	u8				orig_conf;
 	u8				current_conf;
 	u8				resolution;	/* In bits, 9 to 16 */
@@ -540,6 +542,7 @@ static void lm75_remove(void *data)
 	struct i2c_client *client = lm75->client;
 
 	i2c_smbus_write_byte_data(client, LM75_REG_CONF, lm75->orig_conf);
+	regulator_disable(lm75->vs);
 }
 
 static int
@@ -567,6 +570,10 @@ lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	data->client = client;
 	data->kind = kind;
 
+	data->vs = devm_regulator_get(dev, "vs");
+	if (IS_ERR(data->vs))
+		return PTR_ERR(data->vs);
+
 	data->regmap = devm_regmap_init_i2c(client, &lm75_regmap_config);
 	if (IS_ERR(data->regmap))
 		return PTR_ERR(data->regmap);
@@ -581,11 +588,19 @@ lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	data->sample_time = data->params->default_sample_time;
 	data->resolution = data->params->default_resolution;
 
+	/* Enable the power */
+	err = regulator_enable(data->vs);
+	if (err) {
+		dev_err(dev, "failed to enable regulator: %d\n", err);
+		return err;
+	}
+
 	/* Cache original configuration */
 	status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
 	if (status < 0) {
 		dev_dbg(dev, "Can't read config? %d\n", status);
-		return status;
+		err = status;
+		goto disable_regulator;
 	}
 	data->orig_conf = status;
 	data->current_conf = status;
@@ -593,7 +608,7 @@ lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	err = lm75_write_config(data, data->params->set_mask,
 				data->params->clr_mask);
 	if (err)
-		return err;
+		goto disable_regulator;
 
 	err = devm_add_action_or_reset(dev, lm75_remove, data);
 	if (err)
@@ -608,6 +623,10 @@ lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	dev_info(dev, "%s: sensor '%s'\n", dev_name(hwmon_dev), client->name);
 
 	return 0;
+
+disable_regulator:
+	regulator_disable(data->vs);
+	return err;
 }
 
 static const struct i2c_device_id lm75_ids[] = {
-- 
2.25.1

Re: [PATCH v2 3/3] hwmon: (lm75) Add regulator support

[Guenter Roeck]

On Mon, Sep 28, 2020 at 05:39:23PM +0200, Alban Bedel wrote:
> Add regulator support for boards where the sensor first need to be
> powered up before it can be used.
> 
> Signed-off-by: Alban Bedel <alban.bedel@aerq.com>
> ---
> v2: Rely on dummy regulators instead of explicitly handling missing
>     regulator
> ---
>  drivers/hwmon/lm75.c | 23 +++++++++++++++++++++--
>  1 file changed, 21 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c
> index ba0be48aeadd..e394df648c26 100644
> --- a/drivers/hwmon/lm75.c
> +++ b/drivers/hwmon/lm75.c
> @@ -17,6 +17,7 @@
>  #include <linux/of.h>
>  #include <linux/regmap.h>
>  #include <linux/util_macros.h>
> +#include <linux/regulator/consumer.h>
>  #include "lm75.h"
>  
>  /*
> @@ -101,6 +102,7 @@ static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
>  struct lm75_data {
>  	struct i2c_client		*client;
>  	struct regmap			*regmap;
> +	struct regulator		*vs;
>  	u8				orig_conf;
>  	u8				current_conf;
>  	u8				resolution;	/* In bits, 9 to 16 */
> @@ -540,6 +542,7 @@ static void lm75_remove(void *data)
>  	struct i2c_client *client = lm75->client;
>  
>  	i2c_smbus_write_byte_data(client, LM75_REG_CONF, lm75->orig_conf);
> +	regulator_disable(lm75->vs);
>  }
>  
>  static int
> @@ -567,6 +570,10 @@ lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
>  	data->client = client;
>  	data->kind = kind;
>  
> +	data->vs = devm_regulator_get(dev, "vs");
> +	if (IS_ERR(data->vs))
> +		return PTR_ERR(data->vs);
> +
>  	data->regmap = devm_regmap_init_i2c(client, &lm75_regmap_config);
>  	if (IS_ERR(data->regmap))
>  		return PTR_ERR(data->regmap);
> @@ -581,11 +588,19 @@ lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
>  	data->sample_time = data->params->default_sample_time;
>  	data->resolution = data->params->default_resolution;
>  
> +	/* Enable the power */
> +	err = regulator_enable(data->vs);
> +	if (err) {
> +		dev_err(dev, "failed to enable regulator: %d\n", err);
> +		return err;
> +	}
> +
>  	/* Cache original configuration */
>  	status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
>  	if (status < 0) {
>  		dev_dbg(dev, "Can't read config? %d\n", status);
> -		return status;
> +		err = status;
> +		goto disable_regulator;

The point of using devm_add_action_or_reset() was specifically to avoid having
to have the cleanup gotos. On top of that, the lm75_remove() function was
specifically intended to clean up configuration data, not to do anything else.
While hijacking lm75_remove() to also disable the regulator is technically
correct, it makes the code more difficult to understand, and it creates a
potential source for subsequently introduced bugs. Right now I am not inclined
to accept this code as-is. Please provide arguments for handling the cleanup
this way instead of using devm_add_action_or_reset().

Thanks,
Guenter

Re: [PATCH v2 3/3] hwmon: (lm75) Add regulator support

[Bedel, Alban]

[-- Attachment #1: Type: text/plain, Size: 3354 bytes --]

On Mon, 2020-09-28 at 09:39 -0700, Guenter Roeck wrote:
> On Mon, Sep 28, 2020 at 05:39:23PM +0200, Alban Bedel wrote:
> > Add regulator support for boards where the sensor first need to be
> > powered up before it can be used.
> > 
> > Signed-off-by: Alban Bedel <alban.bedel@aerq.com>
> > ---
> > v2: Rely on dummy regulators instead of explicitly handling missing
> >     regulator
> > ---
> >  drivers/hwmon/lm75.c | 23 +++++++++++++++++++++--
> >  1 file changed, 21 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c
> > index ba0be48aeadd..e394df648c26 100644
> > --- a/drivers/hwmon/lm75.c
> > +++ b/drivers/hwmon/lm75.c
> > @@ -17,6 +17,7 @@
> >  #include <linux/of.h>
> >  #include <linux/regmap.h>
> >  #include <linux/util_macros.h>
> > +#include <linux/regulator/consumer.h>
> >  #include "lm75.h"
> >  
> >  /*
> > @@ -101,6 +102,7 @@ static const unsigned short normal_i2c[] = {
> > 0x48, 0x49, 0x4a, 0x4b, 0x4c,
> >  struct lm75_data {
> >  	struct i2c_client		*client;
> >  	struct regmap			*regmap;
> > +	struct regulator		*vs;
> >  	u8				orig_conf;
> >  	u8				current_conf;
> >  	u8				resolution;	/* In bits, 9 to 16
> > */
> > @@ -540,6 +542,7 @@ static void lm75_remove(void *data)
> >  	struct i2c_client *client = lm75->client;
> >  
> >  	i2c_smbus_write_byte_data(client, LM75_REG_CONF, lm75-
> > >orig_conf);
> > +	regulator_disable(lm75->vs);
> >  }
> >  
> >  static int
> > @@ -567,6 +570,10 @@ lm75_probe(struct i2c_client *client, const
> > struct i2c_device_id *id)
> >  	data->client = client;
> >  	data->kind = kind;
> >  
> > +	data->vs = devm_regulator_get(dev, "vs");
> > +	if (IS_ERR(data->vs))
> > +		return PTR_ERR(data->vs);
> > +
> >  	data->regmap = devm_regmap_init_i2c(client,
> > &lm75_regmap_config);
> >  	if (IS_ERR(data->regmap))
> >  		return PTR_ERR(data->regmap);
> > @@ -581,11 +588,19 @@ lm75_probe(struct i2c_client *client, const
> > struct i2c_device_id *id)
> >  	data->sample_time = data->params->default_sample_time;
> >  	data->resolution = data->params->default_resolution;
> >  
> > +	/* Enable the power */
> > +	err = regulator_enable(data->vs);
> > +	if (err) {
> > +		dev_err(dev, "failed to enable regulator: %d\n", err);
> > +		return err;
> > +	}
> > +
> >  	/* Cache original configuration */
> >  	status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
> >  	if (status < 0) {
> >  		dev_dbg(dev, "Can't read config? %d\n", status);
> > -		return status;
> > +		err = status;
> > +		goto disable_regulator;
> 
> The point of using devm_add_action_or_reset() was specifically to avoid having
> to have the cleanup gotos. On top of that, the lm75_remove() function was
> specifically intended to clean up configuration data, not to do anything else.
> While hijacking lm75_remove() to also disable the regulator is technically
> correct, it makes the code more difficult to understand, and it creates a
> potential source for subsequently introduced bugs. Right now I am not inclined
> to accept this code as-is. Please provide arguments for handling the cleanup
> this way instead of using devm_add_action_or_reset().

I wrote it that way to keep the memory usage lower, but I see your
point and will update the patch accordingly.

Alban


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Re: [PATCH v2 1/3] dt-bindings: hwmon: Convert lm75 bindings to yaml

[Rob Herring]

On Mon, Sep 28, 2020 at 05:39:21PM +0200, Alban Bedel wrote:
> In order to automate the verification of DT nodes convert lm75.txt to
> lm75.yaml.
> 
> Signed-off-by: Alban Bedel <alban.bedel@aerq.com>
> ---
> v2: Fix the example to pass `make dt_binding_check`
> ---
>  .../devicetree/bindings/hwmon/lm75.txt        | 39 ------------
>  .../devicetree/bindings/hwmon/lm75.yaml       | 60 +++++++++++++++++++
>  2 files changed, 60 insertions(+), 39 deletions(-)
>  delete mode 100644 Documentation/devicetree/bindings/hwmon/lm75.txt
>  create mode 100644 Documentation/devicetree/bindings/hwmon/lm75.yaml
> 
> diff --git a/Documentation/devicetree/bindings/hwmon/lm75.txt b/Documentation/devicetree/bindings/hwmon/lm75.txt
> deleted file mode 100644
> index 273616702c51..000000000000
> --- a/Documentation/devicetree/bindings/hwmon/lm75.txt
> +++ /dev/null
> @@ -1,39 +0,0 @@
> -*LM75 hwmon sensor.
> -
> -Required properties:
> -- compatible: manufacturer and chip name, one of
> -		"adi,adt75",
> -		"dallas,ds1775",
> -		"dallas,ds75",
> -		"dallas,ds7505",
> -		"gmt,g751",
> -		"national,lm75",
> -		"national,lm75a",
> -		"national,lm75b",
> -		"maxim,max6625",
> -		"maxim,max6626",
> -		"maxim,max31725",
> -		"maxim,max31726",
> -		"maxim,mcp980x",
> -		"nxp,pct2075",
> -		"st,stds75",
> -		"st,stlm75",
> -		"microchip,tcn75",
> -		"ti,tmp100",
> -		"ti,tmp101",
> -		"ti,tmp105",
> -		"ti,tmp112",
> -		"ti,tmp175",
> -		"ti,tmp275",
> -		"ti,tmp75",
> -		"ti,tmp75b",
> -		"ti,tmp75c",
> -
> -- reg: I2C bus address of the device
> -
> -Example:
> -
> -sensor@48 {
> -	compatible = "st,stlm75";
> -	reg = <0x48>;
> -};
> diff --git a/Documentation/devicetree/bindings/hwmon/lm75.yaml b/Documentation/devicetree/bindings/hwmon/lm75.yaml
> new file mode 100644
> index 000000000000..203829c6ba6f
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/hwmon/lm75.yaml
> @@ -0,0 +1,60 @@
> +# SPDX-License-Identifier: GPL-2.0-only or BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/hwmon/lm75.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: LM75 hwmon sensor
> +
> +maintainers:
> +  - Jean Delvare <jdelvare@suse.com>
> +  - Guenter Roeck <linux@roeck-us.net>
> +
> +properties:
> +  compatible:
> +    enum:
> +      - adi,adt75
> +      - dallas,ds1775
> +      - dallas,ds75
> +      - dallas,ds7505
> +      - gmt,g751
> +      - national,lm75
> +      - national,lm75a
> +      - national,lm75b
> +      - maxim,max6625
> +      - maxim,max6626
> +      - maxim,max31725
> +      - maxim,max31726
> +      - maxim,mcp980x
> +      - nxp,pct2075
> +      - st,stds75
> +      - st,stlm75
> +      - microchip,tcn75
> +      - ti,tmp100
> +      - ti,tmp101
> +      - ti,tmp105
> +      - ti,tmp112
> +      - ti,tmp175
> +      - ti,tmp275
> +      - ti,tmp75
> +      - ti,tmp75b
> +      - ti,tmp75c
> +
> +  reg:
> +    maxItems: 1
> +
> +required:
> +  - compatible
> +  - reg

additionalProperties: false

> +
> +examples:
> +  - |
> +    i2c {
> +      #address-cells = <1>;
> +      #size-cells = <0>;
> +
> +      sensor@48 {
> +        compatible = "st,stlm75";
> +        reg = <0x48>;
> +      };
> +    };
> -- 
> 2.25.1
> 

Re: [PATCH v2 2/3] dt-bindings: hwmon: Add the +vs supply to the lm75 bindings

[Rob Herring]

On Mon, 28 Sep 2020 17:39:22 +0200, Alban Bedel wrote:
> Some boards might have a regulator that control the +VS supply, add it
> to the bindings.
> 
> Signed-off-by: Alban Bedel <alban.bedel@aerq.com>
> ---
> v2: Removed the unneeded `maxItems` attribute
> ---
>  Documentation/devicetree/bindings/hwmon/lm75.yaml | 4 ++++
>  1 file changed, 4 insertions(+)
> 

Acked-by: Rob Herring <robh@kernel.org>