[PATCH v4 1/4] iio: ad5755: add support for dt bindings

[PATCH v4 1/4] iio: ad5755: add support for dt bindings

[Sean Nyekjaer]

Still missing a way to provide default modes and settings
for the driver from dt, but I see this as a start.

Signed-off-by: Sean Nyekjaer <sean.nyekjaer-rjjw5hvvQKZaa/9Udqfwiw@public.gmane.org>
---
 drivers/iio/dac/ad5755.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/iio/dac/ad5755.c b/drivers/iio/dac/ad5755.c
index bfb350a..e1b6e78 100644
--- a/drivers/iio/dac/ad5755.c
+++ b/drivers/iio/dac/ad5755.c
@@ -607,6 +607,16 @@ static const struct spi_device_id ad5755_id[] = {
 };
 MODULE_DEVICE_TABLE(spi, ad5755_id);
 
+static const struct of_device_id ad5755_of_match[] = {
+	{ .compatible = "adi,ad5755" },
+	{ .compatible = "adi,ad5755-1" },
+	{ .compatible = "adi,ad5757" },
+	{ .compatible = "adi,ad5735" },
+	{ .compatible = "adi,ad5737" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, ad5755_of_match);
+
 static struct spi_driver ad5755_driver = {
 	.driver = {
 		.name = "ad5755",
-- 
2.7.2

[PATCH v4 2/4] iio: ad5755: Add DT binding documentation

[Sean Nyekjaer]

Signed-off-by: Sean Nyekjaer <sean.nyekjaer-rjjw5hvvQKZaa/9Udqfwiw@public.gmane.org>
Acked-by: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
---
 .../devicetree/bindings/iio/dac/ad5755.txt         | 24 ++++++++++++++++++++++
 1 file changed, 24 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/dac/ad5755.txt

diff --git a/Documentation/devicetree/bindings/iio/dac/ad5755.txt b/Documentation/devicetree/bindings/iio/dac/ad5755.txt
new file mode 100644
index 0000000..4c91583
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/dac/ad5755.txt
@@ -0,0 +1,24 @@
+* Analog Device AD5755 IIO Multi-Channel DAC Linux Driver
+
+Required properties:
+ - compatible: Has to contain one of the following:
+	adi,ad5755
+	adi,ad5755-1
+	adi,ad5757
+	adi,ad5735
+	adi,ad5737
+
+ - reg: spi chip select number for the device
+ - spi-cpha or spi-cpol: is the only modes that is supported
+
+Recommended properties:
+ - spi-max-frequency: Definition as per
+		Documentation/devicetree/bindings/spi/spi-bus.txt
+
+Example:
+dac@0 {
+	compatible = "adi,ad5755";
+	reg = <0>;
+	spi-max-frequency = <1000000>;
+	spi-cpha;
+};
-- 
2.7.2

[PATCH v4 3/4] iio: ad5755: added full support for devicetree

[Sean Nyekjaer]

Devicetree can provide platform data

Signed-off-by: Sean Nyekjaer <sean.nyekjaer-rjjw5hvvQKZaa/9Udqfwiw@public.gmane.org>
---
These large switch cases make the driver hard to read? Does someone have any
ideas to make this more readable?

The dc-dc-phase and channel mode i rather hard to do without defines? Will it
be okay to use them here?
Example:
adi,mode = CURRENT_4mA_20mA or adi,mode = VOLTAGE_PLUSMINUS_10V
They are generic DAC/ADC properties...

Changes since v3:
- replaced '_' with '-'
- Now used actual values instead of register values.

Changes since v2:
- removed defines from DT

 drivers/iio/dac/ad5755.c | 227 ++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 226 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/dac/ad5755.c b/drivers/iio/dac/ad5755.c
index e1b6e78..4a2866e 100644
--- a/drivers/iio/dac/ad5755.c
+++ b/drivers/iio/dac/ad5755.c
@@ -14,6 +14,7 @@
 #include <linux/slab.h>
 #include <linux/sysfs.h>
 #include <linux/delay.h>
+#include <linux/of.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
 #include <linux/platform_data/ad5755.h>
@@ -556,6 +557,223 @@ static const struct ad5755_platform_data ad5755_default_pdata = {
 	},
 };
 
+#ifdef CONFIG_OF
+static struct ad5755_platform_data *ad5755_parse_dt(struct device *dev)
+{
+	struct device_node *np = dev->of_node;
+	struct device_node *pp;
+	struct ad5755_platform_data *pdata;
+	unsigned int tmp;
+	unsigned int tmparray[3];
+	int devnr;
+
+	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
+	if (!pdata)
+		return NULL;
+
+	pdata->ext_dc_dc_compenstation_resistor =
+	    of_property_read_bool(np, "adi,ext-dc-dc-compenstation-resistor");
+
+	if (!of_property_read_u32(np, "adi,dc-dc-phase", &tmp))
+		pdata->dc_dc_phase = tmp;
+	else
+		pdata->dc_dc_phase = AD5755_DC_DC_PHASE_ALL_SAME_EDGE;
+
+	if (!of_property_read_u32(np, "adi,dc-dc-freq", &tmp))
+		switch (tmp) {
+		case 250000:
+			pdata->dc_dc_freq = AD5755_DC_DC_FREQ_250kHZ;
+			break;
+		case 410000:
+			pdata->dc_dc_freq = AD5755_DC_DC_FREQ_410kHZ;
+			break;
+		case 650000:
+			pdata->dc_dc_freq = AD5755_DC_DC_FREQ_650kHZ;
+			break;
+		default:
+			dev_err(dev,
+				"adi,dc-dc-freq out of range selecting 410kHz");
+			pdata->dc_dc_freq = AD5755_DC_DC_FREQ_410kHZ;
+	} else
+		pdata->dc_dc_freq = AD5755_DC_DC_FREQ_410kHZ;
+
+	if (!of_property_read_u32(np, "adi,dc-dc-maxv", &tmp))
+		switch (tmp) {
+		case 23000:
+			pdata->dc_dc_maxv = AD5755_DC_DC_MAXV_23V;
+			break;
+		case 24500:
+			pdata->dc_dc_maxv = AD5755_DC_DC_MAXV_24V5;
+			break;
+		case 27000:
+			pdata->dc_dc_maxv = AD5755_DC_DC_MAXV_27V;
+			break;
+		case 29500:
+			pdata->dc_dc_maxv = AD5755_DC_DC_MAXV_29V5;
+			break;
+		default:
+			dev_err(dev,
+				"adi,dc-dc-maxv out of range selecting 23V");
+			pdata->dc_dc_maxv = AD5755_DC_DC_MAXV_23V;
+	} else
+		pdata->dc_dc_maxv = AD5755_DC_DC_MAXV_23V;
+
+	devnr = 0;
+	for_each_child_of_node(np, pp) {
+		if (devnr > AD5755_NUM_CHANNELS) {
+			dev_err(dev,
+				"There is to many channels defined in DT\n");
+			goto error_out;
+		}
+
+		if (!of_property_read_u32(pp, "adi,mode", &tmp))
+			pdata->dac[devnr].mode = tmp;
+		else
+			pdata->dac[devnr].mode = AD5755_MODE_CURRENT_4mA_20mA;
+
+		pdata->dac[devnr].ext_current_sense_resistor =
+		    of_property_read_bool(pp, "adi,ext-current-sense-resistor");
+
+		pdata->dac[devnr].enable_voltage_overrange =
+		    of_property_read_bool(pp, "adi,enable-voltage-overrange");
+
+		if (!of_property_read_u32_array(pp, "adi,slew", tmparray, 3)) {
+			pdata->dac[devnr].slew.enable = tmparray[0];
+			switch (tmparray[1]) {
+			case 64000:
+				pdata->dac[devnr].slew.rate =
+				    AD5755_SLEW_RATE_64k;
+				break;
+			case 32000:
+				pdata->dac[devnr].slew.rate =
+				    AD5755_SLEW_RATE_32k;
+				break;
+			case 16000:
+				pdata->dac[devnr].slew.rate =
+				    AD5755_SLEW_RATE_16k;
+				break;
+			case 8000:
+				pdata->dac[devnr].slew.rate =
+				    AD5755_SLEW_RATE_8k;
+				break;
+			case 4000:
+				pdata->dac[devnr].slew.rate =
+				    AD5755_SLEW_RATE_4k;
+				break;
+			case 2000:
+				pdata->dac[devnr].slew.rate =
+				    AD5755_SLEW_RATE_2k;
+				break;
+			case 1000:
+				pdata->dac[devnr].slew.rate =
+				    AD5755_SLEW_RATE_1k;
+				break;
+			case 500:
+				pdata->dac[devnr].slew.rate =
+				    AD5755_SLEW_RATE_500;
+				break;
+			case 250:
+				pdata->dac[devnr].slew.rate =
+				    AD5755_SLEW_RATE_250;
+				break;
+			case 125:
+				pdata->dac[devnr].slew.rate =
+				    AD5755_SLEW_RATE_125;
+				break;
+			case 64:
+				pdata->dac[devnr].slew.rate =
+				    AD5755_SLEW_RATE_64;
+				break;
+			case 32:
+				pdata->dac[devnr].slew.rate =
+				    AD5755_SLEW_RATE_32;
+				break;
+			case 16:
+				pdata->dac[devnr].slew.rate =
+				    AD5755_SLEW_RATE_16;
+				break;
+			case 8:
+				pdata->dac[devnr].slew.rate =
+				    AD5755_SLEW_RATE_8;
+				break;
+			case 4:
+				pdata->dac[devnr].slew.rate =
+				    AD5755_SLEW_RATE_4;
+				break;
+			case 0:
+				pdata->dac[devnr].slew.rate =
+				    AD5755_SLEW_RATE_0_5;
+				break;
+			default:
+				dev_err(dev,
+					"channel %d slew rate out of range selecting 64kHz",
+					devnr);
+				pdata->dac[devnr].slew.rate =
+				    AD5755_SLEW_RATE_64k;
+			}
+			switch (tmparray[2]) {
+			case 1:
+				pdata->dac[devnr].slew.step_size =
+				    AD5755_SLEW_STEP_SIZE_1;
+				break;
+			case 2:
+				pdata->dac[devnr].slew.step_size =
+				    AD5755_SLEW_STEP_SIZE_2;
+				break;
+			case 4:
+				pdata->dac[devnr].slew.step_size =
+				    AD5755_SLEW_STEP_SIZE_4;
+				break;
+			case 16:
+				pdata->dac[devnr].slew.step_size =
+				    AD5755_SLEW_STEP_SIZE_16;
+				break;
+			case 32:
+				pdata->dac[devnr].slew.step_size =
+				    AD5755_SLEW_STEP_SIZE_32;
+				break;
+			case 64:
+				pdata->dac[devnr].slew.step_size =
+				    AD5755_SLEW_STEP_SIZE_64;
+				break;
+			case 128:
+				pdata->dac[devnr].slew.step_size =
+				    AD5755_SLEW_STEP_SIZE_128;
+				break;
+			case 256:
+				pdata->dac[devnr].slew.step_size =
+				    AD5755_SLEW_STEP_SIZE_256;
+				break;
+			default:
+				dev_err(dev,
+					"channel %d slew step size out of range selecting 1 LSB",
+					devnr);
+				pdata->dac[devnr].slew.step_size =
+				    AD5755_SLEW_STEP_SIZE_1;
+			}
+		} else {
+			pdata->dac[devnr].slew.enable = false;
+			pdata->dac[devnr].slew.rate = AD5755_SLEW_RATE_64k;
+			pdata->dac[devnr].slew.step_size =
+			    AD5755_SLEW_STEP_SIZE_1;
+		}
+		devnr++;
+	}
+
+	return pdata;
+
+ error_out:
+	devm_kfree(dev, pdata);
+	return NULL;
+}
+#else
+static
+struct adf4350_platform_data *adf4350_parse_dt(struct device *dev)
+{
+	return NULL;
+}
+#endif
+
 static int ad5755_probe(struct spi_device *spi)
 {
 	enum ad5755_type type = spi_get_device_id(spi)->driver_data;
@@ -583,8 +801,15 @@ static int ad5755_probe(struct spi_device *spi)
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->num_channels = AD5755_NUM_CHANNELS;
 
-	if (!pdata)
+	if (spi->dev.of_node)
+		pdata = ad5755_parse_dt(&spi->dev);
+	else
+		pdata = spi->dev.platform_data;
+
+	if (!pdata) {
+		dev_warn(&spi->dev, "no platform data? using default\n");
 		pdata = &ad5755_default_pdata;
+	}
 
 	ret = ad5755_init_channels(indio_dev, pdata);
 	if (ret)
-- 
2.7.2

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[PATCH v4 4/4] iio: ad5755: Add full DT binding documentation

[Sean Nyekjaer]

Signed-off-by: Sean Nyekjaer <sean.nyekjaer-rjjw5hvvQKZaa/9Udqfwiw@public.gmane.org>
---
Still missing some ideas to dc-dc-phase and mode options :-)

Changes since v3:
- replaced '_' with '-'
- Now used actual values instead of register values.

Changes since v2:
 - Removed defines, alot easier to read :-)

 .../devicetree/bindings/iio/dac/ad5755.txt         | 94 ++++++++++++++++++++++
 1 file changed, 94 insertions(+)

diff --git a/Documentation/devicetree/bindings/iio/dac/ad5755.txt b/Documentation/devicetree/bindings/iio/dac/ad5755.txt
index 4c91583..83b4c3f 100644
--- a/Documentation/devicetree/bindings/iio/dac/ad5755.txt
+++ b/Documentation/devicetree/bindings/iio/dac/ad5755.txt
@@ -15,10 +15,104 @@ Recommended properties:
  - spi-max-frequency: Definition as per
 		Documentation/devicetree/bindings/spi/spi-bus.txt
 
+Optional properties:
+See include/dt-bindings/iio/ad5755.h
+ - adi,ext-dc-dc-compenstation-resistor: boolean set if the hardware have an
+					 external resistor and thereby bypasses
+					 the internal compensation resistor.
+ - adi,dc-dc-phase:
+	Valid values for DC DC Phase control is:
+	0: All dc-to-dc converters clock on the same edge.
+	1: Channel A and Channel B clock on the same edge,
+	   Channel C and Channel D clock on opposite edges.
+	2: Channel A and Channel C clock on the same edge,
+	   Channel B and Channel D clock on opposite edges.
+	3: Channel A, Channel B, Channel C, and Channel D
+	   clock 90 degrees out of phase from each other.
+ - adi,dc-dc-freq:
+	Valid values for DC DC frequency is [Hz]:
+	250000
+	410000
+	650000
+ - adi,dc-dc-maxv:
+	Valid values for the maximum allowed Vboost voltage supplied by
+	the dc-to-dc converter is [mV]:
+	23000
+	24500
+	27000
+	29500
+
+Optional for every channel:
+ - adi,mode:
+	Valid values for DAC modes is:
+	0: 0 V to 5 V voltage range.
+	1: 0 V to 10 V voltage range.
+	2: Plus minus 5 V voltage range.
+	3: Plus minus 10 V voltage range.
+	4: 4 mA to 20 mA current range.
+	5: 0 mA to 20 mA current range.
+	6: 0 mA to 24 mA current range.
+ - adi,ext-current-sense-resistor: boolean set if the hardware a external
+				   current sense resistor.
+ - adi,enable-voltage-overrange: boolean enable voltage overrange
+ - adi,slew: Array of slewrate settings should contain 3 fields:
+	1: Should be either 0 or 1 in order to enable or disable slewrate.
+	2: Slew rate settings:
+		Valid values for the slew rate update frequency:
+		64000
+		32000
+		16000
+		8000
+		4000
+		2000
+		1000
+		500
+		250
+		125
+		64
+		32
+		16
+		8
+		4
+		0
+	3: Slew step size:
+		Valid values for the step size LSBs:
+		1
+		2
+		4
+		16
+		32
+		64
+		128
+		256
+
 Example:
 dac@0 {
 	compatible = "adi,ad5755";
 	reg = <0>;
 	spi-max-frequency = <1000000>;
 	spi-cpha;
+	adi,dc-dc-phase = <0>;
+	adi,dc-dc-freq = <1>;
+	adi,dc-dc-maxv = <0>;
+	channel@0 {
+		adi,mode = <4>;
+		adi,ext-current-sense-resistor;
+		adi,slew = <0 64000 1>;
+	};
+	channel@1 {
+		adi,mode = <4>;
+		adi,ext-current-sense-resistor;
+		adi,slew = <0 64000 1>;
+	};
+	channel@2 {
+		adi,mode = <4>;
+		adi,ext-current-sense-resistor;
+		adi,slew = <0 64000 1>;
+	};
+	channel@3 {
+		adi,mode = <4>;
+		adi,ext-current-sense-resistor;
+		adi,slew = <0 64000 1>;
+	};
 };
-- 
2.7.2

Re: [PATCH v4 4/4] iio: ad5755: Add full DT binding documentation

[Rob Herring]

On Tue, Mar 01, 2016 at 12:56:16PM +0100, Sean Nyekjaer wrote:
> Signed-off-by: Sean Nyekjaer <sean.nyekjaer-rjjw5hvvQKZaa/9Udqfwiw@public.gmane.org>
> ---
> Still missing some ideas to dc-dc-phase and mode options :-)

Please combine patches 2 and 4. Binding changes don't have to correlate 
one to one with driver changes.

> 
> Changes since v3:
> - replaced '_' with '-'
> - Now used actual values instead of register values.
> 
> Changes since v2:
>  - Removed defines, alot easier to read :-)
> 
>  .../devicetree/bindings/iio/dac/ad5755.txt         | 94 ++++++++++++++++++++++
>  1 file changed, 94 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/iio/dac/ad5755.txt b/Documentation/devicetree/bindings/iio/dac/ad5755.txt
> index 4c91583..83b4c3f 100644
> --- a/Documentation/devicetree/bindings/iio/dac/ad5755.txt
> +++ b/Documentation/devicetree/bindings/iio/dac/ad5755.txt
> @@ -15,10 +15,104 @@ Recommended properties:
>   - spi-max-frequency: Definition as per
>  		Documentation/devicetree/bindings/spi/spi-bus.txt
>  
> +Optional properties:
> +See include/dt-bindings/iio/ad5755.h
> + - adi,ext-dc-dc-compenstation-resistor: boolean set if the hardware have an
> +					 external resistor and thereby bypasses
> +					 the internal compensation resistor.
> + - adi,dc-dc-phase:
> +	Valid values for DC DC Phase control is:
> +	0: All dc-to-dc converters clock on the same edge.
> +	1: Channel A and Channel B clock on the same edge,
> +	   Channel C and Channel D clock on opposite edges.
> +	2: Channel A and Channel C clock on the same edge,
> +	   Channel B and Channel D clock on opposite edges.
> +	3: Channel A, Channel B, Channel C, and Channel D
> +	   clock 90 degrees out of phase from each other.
> + - adi,dc-dc-freq:

Please append "-hz".

> +	Valid values for DC DC frequency is [Hz]:
> +	250000
> +	410000
> +	650000
> + - adi,dc-dc-maxv:

adi,dc-dc-max-microvolt

Just trying to keep units somewhat standard.

> +	Valid values for the maximum allowed Vboost voltage supplied by
> +	the dc-to-dc converter is [mV]:
> +	23000
> +	24500
> +	27000
> +	29500
> +
> +Optional for every channel:
> + - adi,mode:
> +	Valid values for DAC modes is:
> +	0: 0 V to 5 V voltage range.
> +	1: 0 V to 10 V voltage range.
> +	2: Plus minus 5 V voltage range.
> +	3: Plus minus 10 V voltage range.
> +	4: 4 mA to 20 mA current range.
> +	5: 0 mA to 20 mA current range.
> +	6: 0 mA to 24 mA current range.
> + - adi,ext-current-sense-resistor: boolean set if the hardware a external
> +				   current sense resistor.
> + - adi,enable-voltage-overrange: boolean enable voltage overrange
> + - adi,slew: Array of slewrate settings should contain 3 fields:
> +	1: Should be either 0 or 1 in order to enable or disable slewrate.
> +	2: Slew rate settings:
> +		Valid values for the slew rate update frequency:
> +		64000
> +		32000
> +		16000
> +		8000
> +		4000
> +		2000
> +		1000
> +		500
> +		250
> +		125
> +		64
> +		32
> +		16
> +		8
> +		4
> +		0
> +	3: Slew step size:
> +		Valid values for the step size LSBs:
> +		1
> +		2
> +		4
> +		16
> +		32
> +		64
> +		128
> +		256
> +
>  Example:
>  dac@0 {
>  	compatible = "adi,ad5755";
>  	reg = <0>;
>  	spi-max-frequency = <1000000>;
>  	spi-cpha;
> +	adi,dc-dc-phase = <0>;
> +	adi,dc-dc-freq = <1>;
> +	adi,dc-dc-maxv = <0>;
> +	channel@0 {

unit addresses require a reg property, so add one here.

> +		adi,mode = <4>;
> +		adi,ext-current-sense-resistor;
> +		adi,slew = <0 64000 1>;
> +	};
> +	channel@1 {
> +		adi,mode = <4>;
> +		adi,ext-current-sense-resistor;
> +		adi,slew = <0 64000 1>;
> +	};
> +	channel@2 {
> +		adi,mode = <4>;
> +		adi,ext-current-sense-resistor;
> +		adi,slew = <0 64000 1>;
> +	};
> +	channel@3 {
> +		adi,mode = <4>;
> +		adi,ext-current-sense-resistor;
> +		adi,slew = <0 64000 1>;
> +	};
>  };
> -- 
> 2.7.2
> 
> --
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Re: [PATCH v4 3/4] iio: ad5755: added full support for devicetree

[Jonathan Cameron]

On 01/03/16 11:56, Sean Nyekjaer wrote:
> Devicetree can provide platform data
> 
> Signed-off-by: Sean Nyekjaer <sean.nyekjaer-rjjw5hvvQKZaa/9Udqfwiw@public.gmane.org>
> ---
> These large switch cases make the driver hard to read? Does someone have any
> ideas to make this more readable?
Only option that comes to mind would be to use a look up table and search
it... See below.  Moves the switch statement stuff into a static array.  Can
be done neater than I have below, but you'll get the idea.
> 
> The dc-dc-phase and channel mode i rather hard to do without defines? Will it
> be okay to use them here?
> Example:
> adi,mode = CURRENT_4mA_20mA or adi,mode = VOLTAGE_PLUSMINUS_10V
> They are generic DAC/ADC properties...
I can't think of a better way - there are too many missing cases that are
invalid to break it up into more elements.  So sure, fine in my view as is.
> 
> Changes since v3:
> - replaced '_' with '-'
> - Now used actual values instead of register values.
> 
> Changes since v2:
> - removed defines from DT
> 
>  drivers/iio/dac/ad5755.c | 227 ++++++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 226 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iio/dac/ad5755.c b/drivers/iio/dac/ad5755.c
> index e1b6e78..4a2866e 100644
> --- a/drivers/iio/dac/ad5755.c
> +++ b/drivers/iio/dac/ad5755.c
> @@ -14,6 +14,7 @@
>  #include <linux/slab.h>
>  #include <linux/sysfs.h>
>  #include <linux/delay.h>
> +#include <linux/of.h>
>  #include <linux/iio/iio.h>
>  #include <linux/iio/sysfs.h>
>  #include <linux/platform_data/ad5755.h>
> @@ -556,6 +557,223 @@ static const struct ad5755_platform_data ad5755_default_pdata = {
>  	},
>  };
>  
> +#ifdef CONFIG_OF
> +static struct ad5755_platform_data *ad5755_parse_dt(struct device *dev)
> +{
> +	struct device_node *np = dev->of_node;
> +	struct device_node *pp;
> +	struct ad5755_platform_data *pdata;
> +	unsigned int tmp;
> +	unsigned int tmparray[3];
> +	int devnr;
> +
> +	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
> +	if (!pdata)
> +		return NULL;
> +
> +	pdata->ext_dc_dc_compenstation_resistor =
> +	    of_property_read_bool(np, "adi,ext-dc-dc-compenstation-resistor");
> +
> +	if (!of_property_read_u32(np, "adi,dc-dc-phase", &tmp))
> +		pdata->dc_dc_phase = tmp;
> +	else
> +		pdata->dc_dc_phase = AD5755_DC_DC_PHASE_ALL_SAME_EDGE;
> +
> +	if (!of_property_read_u32(np, "adi,dc-dc-freq", &tmp))
> +		switch (tmp) {
static const int ad5755_dcdc_freq_table[3][2] =
{ { 250000, AD5755_DC_DC_FREQ_250kHZ },
  { 410000, AD5755_DC_DC_FREQ_410kHZ },
  { 650000, AD5755_DC_DC_FREQ_650kZ } };

  for (i = 0; i < 3; i++) {
      if (tmp == ad5755_dcdc_freq_table[i][0]) {
      	 pdata->dc_dc_freq = ad5755_dcdc_freq_table[i][1];
	 break;
      }
  if (i == 3) {
     dev_err(dev,
             "adi,dc-dc-freq out of range selecting 410kHz");
     pdata->dc_dc_freq = AD5755_DC_DC_FREQ_410kHZ;
  }

Or something along those lines..  Makes more sense for the larger ones.
> +		case 250000:
> +			pdata->dc_dc_freq = AD5755_DC_DC_FREQ_250kHZ;
> +			break;
> +		case 410000:
> +			pdata->dc_dc_freq = AD5755_DC_DC_FREQ_410kHZ;
> +			break;
> +		case 650000:
> +			pdata->dc_dc_freq = AD5755_DC_DC_FREQ_650kHZ;
> +			break;
> +		default:
> +			dev_err(dev,
> +				"adi,dc-dc-freq out of range selecting 410kHz");
> +			pdata->dc_dc_freq = AD5755_DC_DC_FREQ_410kHZ;
> +	} else
> +		pdata->dc_dc_freq = AD5755_DC_DC_FREQ_410kHZ;
> +
> +	if (!of_property_read_u32(np, "adi,dc-dc-maxv", &tmp))
> +		switch (tmp) {
> +		case 23000:
> +			pdata->dc_dc_maxv = AD5755_DC_DC_MAXV_23V;
> +			break;
> +		case 24500:
> +			pdata->dc_dc_maxv = AD5755_DC_DC_MAXV_24V5;
> +			break;
> +		case 27000:
> +			pdata->dc_dc_maxv = AD5755_DC_DC_MAXV_27V;
> +			break;
> +		case 29500:
> +			pdata->dc_dc_maxv = AD5755_DC_DC_MAXV_29V5;
> +			break;
> +		default:
> +			dev_err(dev,
> +				"adi,dc-dc-maxv out of range selecting 23V");
> +			pdata->dc_dc_maxv = AD5755_DC_DC_MAXV_23V;
> +	} else
> +		pdata->dc_dc_maxv = AD5755_DC_DC_MAXV_23V;
> +
> +	devnr = 0;
> +	for_each_child_of_node(np, pp) {
> +		if (devnr > AD5755_NUM_CHANNELS) {
> +			dev_err(dev,
> +				"There is to many channels defined in DT\n");
> +			goto error_out;
> +		}
> +
> +		if (!of_property_read_u32(pp, "adi,mode", &tmp))
> +			pdata->dac[devnr].mode = tmp;
> +		else
> +			pdata->dac[devnr].mode = AD5755_MODE_CURRENT_4mA_20mA;
> +
> +		pdata->dac[devnr].ext_current_sense_resistor =
> +		    of_property_read_bool(pp, "adi,ext-current-sense-resistor");
> +
> +		pdata->dac[devnr].enable_voltage_overrange =
> +		    of_property_read_bool(pp, "adi,enable-voltage-overrange");
> +
> +		if (!of_property_read_u32_array(pp, "adi,slew", tmparray, 3)) {
> +			pdata->dac[devnr].slew.enable = tmparray[0];
> +			switch (tmparray[1]) {
> +			case 64000:
> +				pdata->dac[devnr].slew.rate =
> +				    AD5755_SLEW_RATE_64k;
> +				break;
> +			case 32000:
> +				pdata->dac[devnr].slew.rate =
> +				    AD5755_SLEW_RATE_32k;
> +				break;
> +			case 16000:
> +				pdata->dac[devnr].slew.rate =
> +				    AD5755_SLEW_RATE_16k;
> +				break;
> +			case 8000:
> +				pdata->dac[devnr].slew.rate =
> +				    AD5755_SLEW_RATE_8k;
> +				break;
> +			case 4000:
> +				pdata->dac[devnr].slew.rate =
> +				    AD5755_SLEW_RATE_4k;
> +				break;
> +			case 2000:
> +				pdata->dac[devnr].slew.rate =
> +				    AD5755_SLEW_RATE_2k;
> +				break;
> +			case 1000:
> +				pdata->dac[devnr].slew.rate =
> +				    AD5755_SLEW_RATE_1k;
> +				break;
> +			case 500:
> +				pdata->dac[devnr].slew.rate =
> +				    AD5755_SLEW_RATE_500;
> +				break;
> +			case 250:
> +				pdata->dac[devnr].slew.rate =
> +				    AD5755_SLEW_RATE_250;
> +				break;
> +			case 125:
> +				pdata->dac[devnr].slew.rate =
> +				    AD5755_SLEW_RATE_125;
> +				break;
> +			case 64:
> +				pdata->dac[devnr].slew.rate =
> +				    AD5755_SLEW_RATE_64;
> +				break;
> +			case 32:
> +				pdata->dac[devnr].slew.rate =
> +				    AD5755_SLEW_RATE_32;
> +				break;
> +			case 16:
> +				pdata->dac[devnr].slew.rate =
> +				    AD5755_SLEW_RATE_16;
> +				break;
> +			case 8:
> +				pdata->dac[devnr].slew.rate =
> +				    AD5755_SLEW_RATE_8;
> +				break;
> +			case 4:
> +				pdata->dac[devnr].slew.rate =
> +				    AD5755_SLEW_RATE_4;
> +				break;
> +			case 0:
> +				pdata->dac[devnr].slew.rate =
> +				    AD5755_SLEW_RATE_0_5;
> +				break;
> +			default:
> +				dev_err(dev,
> +					"channel %d slew rate out of range selecting 64kHz",
> +					devnr);
> +				pdata->dac[devnr].slew.rate =
> +				    AD5755_SLEW_RATE_64k;
> +			}
> +			switch (tmparray[2]) {
> +			case 1:
> +				pdata->dac[devnr].slew.step_size =
> +				    AD5755_SLEW_STEP_SIZE_1;
> +				break;
> +			case 2:
> +				pdata->dac[devnr].slew.step_size =
> +				    AD5755_SLEW_STEP_SIZE_2;
> +				break;
> +			case 4:
> +				pdata->dac[devnr].slew.step_size =
> +				    AD5755_SLEW_STEP_SIZE_4;
> +				break;
> +			case 16:
> +				pdata->dac[devnr].slew.step_size =
> +				    AD5755_SLEW_STEP_SIZE_16;
> +				break;
> +			case 32:
> +				pdata->dac[devnr].slew.step_size =
> +				    AD5755_SLEW_STEP_SIZE_32;
> +				break;
> +			case 64:
> +				pdata->dac[devnr].slew.step_size =
> +				    AD5755_SLEW_STEP_SIZE_64;
> +				break;
> +			case 128:
> +				pdata->dac[devnr].slew.step_size =
> +				    AD5755_SLEW_STEP_SIZE_128;
> +				break;
> +			case 256:
> +				pdata->dac[devnr].slew.step_size =
> +				    AD5755_SLEW_STEP_SIZE_256;
> +				break;
> +			default:
> +				dev_err(dev,
> +					"channel %d slew step size out of range selecting 1 LSB",
> +					devnr);
> +				pdata->dac[devnr].slew.step_size =
> +				    AD5755_SLEW_STEP_SIZE_1;
> +			}
> +		} else {
> +			pdata->dac[devnr].slew.enable = false;
> +			pdata->dac[devnr].slew.rate = AD5755_SLEW_RATE_64k;
> +			pdata->dac[devnr].slew.step_size =
> +			    AD5755_SLEW_STEP_SIZE_1;
> +		}
> +		devnr++;
> +	}
> +
> +	return pdata;
> +
> + error_out:
> +	devm_kfree(dev, pdata);
> +	return NULL;
> +}
> +#else
> +static
> +struct adf4350_platform_data *adf4350_parse_dt(struct device *dev)
> +{
> +	return NULL;
> +}
> +#endif
> +
>  static int ad5755_probe(struct spi_device *spi)
>  {
>  	enum ad5755_type type = spi_get_device_id(spi)->driver_data;
> @@ -583,8 +801,15 @@ static int ad5755_probe(struct spi_device *spi)
>  	indio_dev->modes = INDIO_DIRECT_MODE;
>  	indio_dev->num_channels = AD5755_NUM_CHANNELS;
>  
> -	if (!pdata)
> +	if (spi->dev.of_node)
> +		pdata = ad5755_parse_dt(&spi->dev);
> +	else
> +		pdata = spi->dev.platform_data;
> +
> +	if (!pdata) {
> +		dev_warn(&spi->dev, "no platform data? using default\n");
>  		pdata = &ad5755_default_pdata;
> +	}
>  
>  	ret = ad5755_init_channels(indio_dev, pdata);
>  	if (ret)
>