[PATCH v5] hwmon: ads7828 optional parameters from the device tree

[PATCH v5] hwmon: ads7828 optional parameters from the device tree

[Sam Povilus]

Adding the ability for the ads7828 and ads7830 to use the device tree to
get their optional parameters, instead of using platform devices. This
allows people using custom boards to also use the ads7828 in a non-default
manner.

v2: conforming to coding style
v3: changing from "_" to "-" for device tree entries
v4: using regulator subsystem for voltage source, renaming differential
    input property
v5: checking for invalid vref values sooner and returning error if they are
    bad, not warning user.

Signed-off-by: Sam Povilus <kernel.development-iezDrKAjiWs@public.gmane.org>
---
 .../devicetree/bindings/hwmon/ads7828.txt          | 26 ++++++++++++++++++++++
 .../devicetree/bindings/i2c/trivial-devices.txt    |  2 --
 drivers/hwmon/ads7828.c                            | 21 +++++++++++++++++
 3 files changed, 47 insertions(+), 2 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/hwmon/ads7828.txt

diff --git a/Documentation/devicetree/bindings/hwmon/ads7828.txt b/Documentation/devicetree/bindings/hwmon/ads7828.txt
new file mode 100644
index 000000000000..5a0c4a7c6144
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwmon/ads7828.txt
@@ -0,0 +1,26 @@
+ads7828 properties
+
+Required properties:
+- compatible: Should be one of
+	       ti,ads7828
+	       ti,ads7830
+- reg: I2C address
+
+Optional properties:
+
+- ti,differential-input
+  Set to use the device in differential mode.
+- vref
+  The external reference on the device is set to this regulators output. If it
+  does not exists the internal reference will be used and output by the ads78xx
+  on the "external vref" pin.
+
+  Example ADS7828 node:
+
+  ads7828: ads@48 {
+  	   comatible = "ti,ads7828";
+	   reg = <0x48>;
+	   vref = <&vref>;
+	   ti,differential-input;
+  };
+
diff --git a/Documentation/devicetree/bindings/i2c/trivial-devices.txt b/Documentation/devicetree/bindings/i2c/trivial-devices.txt
index cdd7b48826c3..87648909f6ce 100644
--- a/Documentation/devicetree/bindings/i2c/trivial-devices.txt
+++ b/Documentation/devicetree/bindings/i2c/trivial-devices.txt
@@ -163,8 +163,6 @@ st,m41t00		Serial real-time clock (RTC)
 st,m41t62		Serial real-time clock (RTC) with alarm
 st,m41t80		M41T80 - SERIAL ACCESS RTC WITH ALARMS
 taos,tsl2550		Ambient Light Sensor with SMBUS/Two Wire Serial Interface
-ti,ads7828		8-Channels, 12-bit ADC
-ti,ads7830		8-Channels, 8-bit ADC
 ti,tsc2003		I2C Touch-Screen Controller
 ti,tmp102		Low Power Digital Temperature Sensor with SMBUS/Two Wire Serial Interface
 ti,tmp103		Low Power Digital Temperature Sensor with SMBUS/Two Wire Serial Interface
diff --git a/drivers/hwmon/ads7828.c b/drivers/hwmon/ads7828.c
index ee396ff167d9..0be4804a9e59 100644
--- a/drivers/hwmon/ads7828.c
+++ b/drivers/hwmon/ads7828.c
@@ -34,6 +34,9 @@
 #include <linux/platform_data/ads7828.h>
 #include <linux/regmap.h>
 #include <linux/slab.h>
+#include <linux/regulator/consumer.h>
+
+#define MV_TO_UV 1000
 
 /* The ADS7828 registers */
 #define ADS7828_CMD_SD_SE	0x80	/* Single ended inputs */
@@ -118,9 +121,12 @@ static int ads7828_probe(struct i2c_client *client,
 	struct ads7828_data *data;
 	struct device *hwmon_dev;
 	unsigned int vref_mv = ADS7828_INT_VREF_MV;
+	unsigned int vref_uv;
 	bool diff_input = false;
 	bool ext_vref = false;
 	unsigned int regval;
+	struct regulator *reg;
+
 
 	data = devm_kzalloc(dev, sizeof(struct ads7828_data), GFP_KERNEL);
 	if (!data)
@@ -131,6 +137,21 @@ static int ads7828_probe(struct i2c_client *client,
 		ext_vref = pdata->ext_vref;
 		if (ext_vref && pdata->vref_mv)
 			vref_mv = pdata->vref_mv;
+	} else if (dev->of_node) {
+		if (of_get_property(dev->of_node, "ti,differential-input",
+				    NULL))
+			diff_input = true;
+		reg = devm_regulator_get_optional(dev, "vref");
+		if (!IS_ERR(reg)) {
+			vref_uv = regulator_get_voltage(reg);
+			if ((vref_uv >= ADS7828_EXT_VREF_MV_MIN * MV_TO_UV) &&
+			    (vref_uv <= ADS7828_EXT_VREF_MV_MAX * MV_TO_UV)) {
+				vref_mv = DIV_ROUND_CLOSEST(vref_uv, MV_TO_UV);
+				ext_vref = true;
+			} else {
+				return  -EINVAL;
+			}
+		}
 	}
 
 	/* Bound Vref with min/max values */
-- 
2.11.0

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Re: [PATCH v5] hwmon: ads7828 optional parameters from the device tree

[Guenter Roeck]

On 03/20/2017 08:24 PM, Sam Povilus wrote:
> Adding the ability for the ads7828 and ads7830 to use the device tree to
> get their optional parameters, instead of using platform devices. This
> allows people using custom boards to also use the ads7828 in a non-default
> manner.
>
> v2: conforming to coding style
> v3: changing from "_" to "-" for device tree entries
> v4: using regulator subsystem for voltage source, renaming differential
>     input property
> v5: checking for invalid vref values sooner and returning error if they are
>     bad, not warning user.
>
> Signed-off-by: Sam Povilus <kernel.development-iezDrKAjiWs@public.gmane.org>
> ---
>  .../devicetree/bindings/hwmon/ads7828.txt          | 26 ++++++++++++++++++++++
>  .../devicetree/bindings/i2c/trivial-devices.txt    |  2 --
>  drivers/hwmon/ads7828.c                            | 21 +++++++++++++++++
>  3 files changed, 47 insertions(+), 2 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/hwmon/ads7828.txt
>
> diff --git a/Documentation/devicetree/bindings/hwmon/ads7828.txt b/Documentation/devicetree/bindings/hwmon/ads7828.txt
> new file mode 100644
> index 000000000000..5a0c4a7c6144
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/hwmon/ads7828.txt
> @@ -0,0 +1,26 @@
> +ads7828 properties
> +
> +Required properties:
> +- compatible: Should be one of
> +	       ti,ads7828
> +	       ti,ads7830
> +- reg: I2C address
> +
> +Optional properties:
> +
> +- ti,differential-input
> +  Set to use the device in differential mode.
> +- vref
> +  The external reference on the device is set to this regulators output. If it
> +  does not exists the internal reference will be used and output by the ads78xx
> +  on the "external vref" pin.
> +
> +  Example ADS7828 node:
> +
> +  ads7828: ads@48 {
> +  	   comatible = "ti,ads7828";

s/comatible/compatible/

> +	   reg = <0x48>;
> +	   vref = <&vref>;

Looking into the source of of_get_regulator(), either this has to be vref-supply
or I am missing something.

Didn't I mention all this before ?

> +	   ti,differential-input;
> +  };
> +
> diff --git a/Documentation/devicetree/bindings/i2c/trivial-devices.txt b/Documentation/devicetree/bindings/i2c/trivial-devices.txt
> index cdd7b48826c3..87648909f6ce 100644
> --- a/Documentation/devicetree/bindings/i2c/trivial-devices.txt
> +++ b/Documentation/devicetree/bindings/i2c/trivial-devices.txt
> @@ -163,8 +163,6 @@ st,m41t00		Serial real-time clock (RTC)
>  st,m41t62		Serial real-time clock (RTC) with alarm
>  st,m41t80		M41T80 - SERIAL ACCESS RTC WITH ALARMS
>  taos,tsl2550		Ambient Light Sensor with SMBUS/Two Wire Serial Interface
> -ti,ads7828		8-Channels, 12-bit ADC
> -ti,ads7830		8-Channels, 8-bit ADC
>  ti,tsc2003		I2C Touch-Screen Controller
>  ti,tmp102		Low Power Digital Temperature Sensor with SMBUS/Two Wire Serial Interface
>  ti,tmp103		Low Power Digital Temperature Sensor with SMBUS/Two Wire Serial Interface
> diff --git a/drivers/hwmon/ads7828.c b/drivers/hwmon/ads7828.c
> index ee396ff167d9..0be4804a9e59 100644
> --- a/drivers/hwmon/ads7828.c
> +++ b/drivers/hwmon/ads7828.c
> @@ -34,6 +34,9 @@
>  #include <linux/platform_data/ads7828.h>
>  #include <linux/regmap.h>
>  #include <linux/slab.h>
> +#include <linux/regulator/consumer.h>

alphabetic order please

> +
> +#define MV_TO_UV 1000
>
>  /* The ADS7828 registers */
>  #define ADS7828_CMD_SD_SE	0x80	/* Single ended inputs */
> @@ -118,9 +121,12 @@ static int ads7828_probe(struct i2c_client *client,
>  	struct ads7828_data *data;
>  	struct device *hwmon_dev;
>  	unsigned int vref_mv = ADS7828_INT_VREF_MV;
> +	unsigned int vref_uv;
>  	bool diff_input = false;
>  	bool ext_vref = false;
>  	unsigned int regval;
> +	struct regulator *reg;
> +
>

Please no double empty lines.

>  	data = devm_kzalloc(dev, sizeof(struct ads7828_data), GFP_KERNEL);
>  	if (!data)
> @@ -131,6 +137,21 @@ static int ads7828_probe(struct i2c_client *client,
>  		ext_vref = pdata->ext_vref;
>  		if (ext_vref && pdata->vref_mv)
>  			vref_mv = pdata->vref_mv;
> +	} else if (dev->of_node) {
> +		if (of_get_property(dev->of_node, "ti,differential-input",
> +				    NULL))
> +			diff_input = true;
> +		reg = devm_regulator_get_optional(dev, "vref");
> +		if (!IS_ERR(reg)) {
> +			vref_uv = regulator_get_voltage(reg);
> +			if ((vref_uv >= ADS7828_EXT_VREF_MV_MIN * MV_TO_UV) &&
> +			    (vref_uv <= ADS7828_EXT_VREF_MV_MAX * MV_TO_UV)) {
> +				vref_mv = DIV_ROUND_CLOSEST(vref_uv, MV_TO_UV);
> +				ext_vref = true;
> +			} else {
> +				return  -EINVAL;
> +			}

Easier would be
			vref_mv = DIV_ROUND_CLOSEST(vref_uv, 1000);
			if (vref_mv < ADS7828_EXT_VREF_MV_MIN ||
			    vref_mv > ADS7828_EXT_VREF_MV_MAX)
				return -EINVAL;
			ext_vref = true;

I don't think we need the MV_TO_UV define.

> +		}
>  	}
>
>  	/* Bound Vref with min/max values */
>

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Re: [PATCH v5] hwmon: ads7828 optional parameters from the device tree

[Wolfram Sang]

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>  .../devicetree/bindings/i2c/trivial-devices.txt    |  2 --

This file is about to get moved one directory up:

https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git/commit/?h=dt/next&id=b7e252fcddfa573bb1ee275b53bba6cef85671d4

Just so you know already...


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Re: [PATCH v5] hwmon: ads7828 optional parameters from the device tree

[Sam Povilus]

On Wed, Mar 22, 2017 at 09:42:40AM +0100, Wolfram Sang wrote:
> 
> >  .../devicetree/bindings/i2c/trivial-devices.txt    |  2 --
> 
> This file is about to get moved one directory up:
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git/commit/?h=dt/next&id=b7e252fcddfa573bb1ee275b53bba6cef85671d4
> 
> Just so you know already...
> 

Thanks! I'm a bit new to this, what's the best way for me to handle
this? Submit against Linus' tree (presumably making a merge nightmare
for someone) or rebase my branch off robh's (and presumably risking some
other branch's patch conflicting)?

Re: [PATCH v5] hwmon: ads7828 optional parameters from the device tree

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 680 bytes --]

On Wed, Mar 22, 2017 at 07:05:55AM -0600, Sam Povilus wrote:
> On Wed, Mar 22, 2017 at 09:42:40AM +0100, Wolfram Sang wrote:
> > 
> > >  .../devicetree/bindings/i2c/trivial-devices.txt    |  2 --
> > 
> > This file is about to get moved one directory up:
> > 
> > https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git/commit/?h=dt/next&id=b7e252fcddfa573bb1ee275b53bba6cef85671d4
> > 
> > Just so you know already...
> > 
> 
> Thanks! I'm a bit new to this, what's the best way for me to handle
> this?

I mentioned this also for the HWMON maintainers. They will let you know
their preference and if you need to do something.

Regards,

   Wolfram


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Re: [PATCH v5] hwmon: ads7828 optional parameters from the device tree

[Rob Herring]

On Wed, Mar 22, 2017 at 07:05:55AM -0600, Sam Povilus wrote:
> On Wed, Mar 22, 2017 at 09:42:40AM +0100, Wolfram Sang wrote:
> > 
> > >  .../devicetree/bindings/i2c/trivial-devices.txt    |  2 --
> > 
> > This file is about to get moved one directory up:
> > 
> > https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git/commit/?h=dt/next&id=b7e252fcddfa573bb1ee275b53bba6cef85671d4
> > 
> > Just so you know already...
> > 
> 
> Thanks! I'm a bit new to this, what's the best way for me to handle
> this? Submit against Linus' tree (presumably making a merge nightmare
> for someone) or rebase my branch off robh's (and presumably risking some
> other branch's patch conflicting)?

Send me a separate patch for just this file and I'll pick it up.

Rob

Re: [PATCH v5] hwmon: ads7828 optional parameters from the device tree

[Guenter Roeck]

On Fri, Mar 24, 2017 at 11:10:03AM -0500, Rob Herring wrote:
> On Wed, Mar 22, 2017 at 07:05:55AM -0600, Sam Povilus wrote:
> > On Wed, Mar 22, 2017 at 09:42:40AM +0100, Wolfram Sang wrote:
> > > 
> > > >  .../devicetree/bindings/i2c/trivial-devices.txt    |  2 --
> > > 
> > > This file is about to get moved one directory up:
> > > 
> > > https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git/commit/?h=dt/next&id=b7e252fcddfa573bb1ee275b53bba6cef85671d4
> > > 
> > > Just so you know already...
> > > 
> > 
> > Thanks! I'm a bit new to this, what's the best way for me to handle
> > this? Submit against Linus' tree (presumably making a merge nightmare
> > for someone) or rebase my branch off robh's (and presumably risking some
> > other branch's patch conflicting)?
> 
> Send me a separate patch for just this file and I'll pick it up.
> 
Agreed, that seems to be the best approach.

Thanks,
Guenter

Re: [PATCH v5] hwmon: ads7828 optional parameters from the device tree

[Rob Herring]

On Mon, Mar 20, 2017 at 09:24:34PM -0600, Sam Povilus wrote:
> Adding the ability for the ads7828 and ads7830 to use the device tree to
> get their optional parameters, instead of using platform devices. This
> allows people using custom boards to also use the ads7828 in a non-default
> manner.
> 
> v2: conforming to coding style
> v3: changing from "_" to "-" for device tree entries
> v4: using regulator subsystem for voltage source, renaming differential
>     input property
> v5: checking for invalid vref values sooner and returning error if they are
>     bad, not warning user.
> 
> Signed-off-by: Sam Povilus <kernel.development@povil.us>
> ---
>  .../devicetree/bindings/hwmon/ads7828.txt          | 26 ++++++++++++++++++++++
>  .../devicetree/bindings/i2c/trivial-devices.txt    |  2 --
>  drivers/hwmon/ads7828.c                            | 21 +++++++++++++++++
>  3 files changed, 47 insertions(+), 2 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/hwmon/ads7828.txt
> 
> diff --git a/Documentation/devicetree/bindings/hwmon/ads7828.txt b/Documentation/devicetree/bindings/hwmon/ads7828.txt
> new file mode 100644
> index 000000000000..5a0c4a7c6144
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/hwmon/ads7828.txt
> @@ -0,0 +1,26 @@
> +ads7828 properties
> +
> +Required properties:
> +- compatible: Should be one of
> +	       ti,ads7828
> +	       ti,ads7830
> +- reg: I2C address
> +
> +Optional properties:
> +
> +- ti,differential-input
> +  Set to use the device in differential mode.
> +- vref

What does this point to?

Should be vref-supply?

> +  The external reference on the device is set to this regulators output. If it
> +  does not exists the internal reference will be used and output by the ads78xx
> +  on the "external vref" pin.
> +
> +  Example ADS7828 node:
> +
> +  ads7828: ads@48 {

adc@...

> +  	   comatible = "ti,ads7828";
> +	   reg = <0x48>;
> +	   vref = <&vref>;

Add a vref node to the example.

> +	   ti,differential-input;
> +  };
> +