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* [PATCH 1/6] iio: ad7949: Support internal Vref
@ 2019-05-01 21:16 Adam Michaelis
  2019-05-01 21:16 ` [PATCH 2/6] dt-bindings: iio: ad7949: Add adi,reference-select Adam Michaelis
                   ` (5 more replies)
  0 siblings, 6 replies; 13+ messages in thread
From: Adam Michaelis @ 2019-05-01 21:16 UTC (permalink / raw)
  To: linux-iio
  Cc: lars, michael.hennerich, jic23, knaack.h, pmeerw, robh+dt,
	mark.rutland, charles-antoine.couret, devicetree, brandon.maier,
	clayton.shotwell, Adam Michaelis

Adding configurable (via device tree) options to select either an external
reference voltage (default, original implementation) or one of the two
internal reference voltages provided by the AD7949 part family.

Signed-off-by: Adam Michaelis <adam.michaelis@rockwellcollins.com>
---
 drivers/iio/adc/ad7949.c | 84 +++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 66 insertions(+), 18 deletions(-)

diff --git a/drivers/iio/adc/ad7949.c b/drivers/iio/adc/ad7949.c
index ac0ffff6c5ae..1c49eed298d8 100644
--- a/drivers/iio/adc/ad7949.c
+++ b/drivers/iio/adc/ad7949.c
@@ -11,6 +11,7 @@
 #include <linux/module.h>
 #include <linux/regulator/consumer.h>
 #include <linux/spi/spi.h>
+#include <linux/of.h>
 
 #define AD7949_MASK_CHANNEL_SEL		GENMASK(9, 7)
 #define AD7949_MASK_TOTAL		GENMASK(13, 0)
@@ -24,6 +25,18 @@ enum {
 	ID_AD7689,
 };
 
+enum ad7949_ref_sel {
+	AD7949_REF_2V5 = 0, /* 2.5V internal ref + temp sensor */
+	AD7949_REF_4V0, /* 4.096V internal ref + temp sensor */
+	AD7949_REF_EXT_TEMP, /* External ref + temp sensor, no buffer */
+	AD7949_REF_EXT_TEMP_BUF, /* External ref + temp sensor + buffer */
+	AD7949_REF_RSRV_4,
+	AD7949_REF_RSRV_5,
+	AD7949_REF_EXT, /* External ref, no temp, no buffer */
+	AD7949_REF_EXT_BUF, /* External ref + buffer, no temp */
+	AD7949_REF_MAX,
+};
+
 struct ad7949_adc_spec {
 	u8 num_channels;
 	u8 resolution;
@@ -41,6 +54,7 @@ struct ad7949_adc_spec {
  * @vref: regulator generating Vref
  * @iio_dev: reference to iio structure
  * @spi: reference to spi structure
+ * @ref_sel: selected reference voltage source
  * @resolution: resolution of the chip
  * @cfg: copy of the configuration register
  * @current_channel: current channel in use
@@ -51,6 +65,7 @@ struct ad7949_adc_chip {
 	struct regulator *vref;
 	struct iio_dev *indio_dev;
 	struct spi_device *spi;
+	enum ad7949_ref_sel ref_sel;
 	u8 resolution;
 	u16 cfg;
 	unsigned int current_channel;
@@ -187,11 +202,20 @@ static int ad7949_spi_read_raw(struct iio_dev *indio_dev,
 		return IIO_VAL_INT;
 
 	case IIO_CHAN_INFO_SCALE:
-		ret = regulator_get_voltage(ad7949_adc->vref);
-		if (ret < 0)
-			return ret;
+		if (ad7949_adc->vref) {
+			ret = regulator_get_voltage(ad7949_adc->vref);
+			if (ret < 0)
+				return ret;
+
+			*val = ret / 5000;
+		} else if (ad7949_adc->ref_sel == AD7949_REF_2V5) {
+			*val = 2500;
+		} else if (ad7949_adc->ref_sel == AD7949_REF_4V0) {
+			*val = 4096;
+		} else {
+			return -EINVAL;
+		}
 
-		*val = ret / 5000;
 		return IIO_VAL_INT;
 	}
 
@@ -223,10 +247,18 @@ static int ad7949_spi_init(struct ad7949_adc_chip *ad7949_adc)
 {
 	int ret;
 	int val;
+	u16 adc_config = 0;
 
-	/* Sequencer disabled, CFG readback disabled, IN0 as default channel */
 	ad7949_adc->current_channel = 0;
-	ret = ad7949_spi_write_cfg(ad7949_adc, 0x3C79, AD7949_MASK_TOTAL);
+	ad7949_adc->cfg = 0;
+
+	adc_config = (0x3c << 8);
+	adc_config |= ((ad7949_adc->current_channel & 0x07) << 7);
+	adc_config |= (1 << 6);
+	adc_config |= (ad7949_adc->ref_sel << 3);
+	adc_config |= 1;
+
+	ret = ad7949_spi_write_cfg(ad7949_adc, adc_config, AD7949_MASK_TOTAL);
 
 	/*
 	 * Do two dummy conversions to apply the first configuration setting.
@@ -245,6 +277,7 @@ static int ad7949_spi_probe(struct spi_device *spi)
 	struct ad7949_adc_chip *ad7949_adc;
 	struct iio_dev *indio_dev;
 	int ret;
+	u32 temp;
 
 	indio_dev = devm_iio_device_alloc(dev, sizeof(*ad7949_adc));
 	if (!indio_dev) {
@@ -263,21 +296,34 @@ static int ad7949_spi_probe(struct spi_device *spi)
 	ad7949_adc = iio_priv(indio_dev);
 	ad7949_adc->indio_dev = indio_dev;
 	ad7949_adc->spi = spi;
+	ad7949_adc->vref = NULL;
 
 	spec = &ad7949_adc_spec[spi_get_device_id(spi)->driver_data];
 	indio_dev->num_channels = spec->num_channels;
 	ad7949_adc->resolution = spec->resolution;
 
-	ad7949_adc->vref = devm_regulator_get(dev, "vref");
-	if (IS_ERR(ad7949_adc->vref)) {
-		dev_err(dev, "fail to request regulator\n");
-		return PTR_ERR(ad7949_adc->vref);
-	}
-
-	ret = regulator_enable(ad7949_adc->vref);
-	if (ret < 0) {
-		dev_err(dev, "fail to enable regulator\n");
-		return ret;
+	ret = of_property_read_u32(ad7949_adc->indio_dev->dev.of_node,
+			"adi,reference-select",
+			&temp);
+	if ((ret == 0) && (temp < AD7949_REF_MAX))
+		ad7949_adc->ref_sel = (enum ad7949_ref_sel)temp;
+	else
+		ad7949_adc->ref_sel = AD7949_REF_EXT_BUF;
+
+	/* Check whether using external Vref */
+	if ((ad7949_adc->ref_sel != AD7949_REF_2V5) &&
+			(ad7949_adc->ref_sel != AD7949_REF_4V0)) {
+		ad7949_adc->vref = devm_regulator_get(dev, "vref");
+		if (IS_ERR(ad7949_adc->vref)) {
+			dev_err(dev, "fail to request regulator\n");
+			return PTR_ERR(ad7949_adc->vref);
+		}
+
+		ret = regulator_enable(ad7949_adc->vref);
+		if (ret < 0) {
+			dev_err(dev, "fail to enable regulator\n");
+			return ret;
+		}
 	}
 
 	mutex_init(&ad7949_adc->lock);
@@ -298,7 +344,8 @@ static int ad7949_spi_probe(struct spi_device *spi)
 
 err:
 	mutex_destroy(&ad7949_adc->lock);
-	regulator_disable(ad7949_adc->vref);
+	if (ad7949_adc->vref)
+		regulator_disable(ad7949_adc->vref);
 
 	return ret;
 }
@@ -310,7 +357,8 @@ static int ad7949_spi_remove(struct spi_device *spi)
 
 	iio_device_unregister(indio_dev);
 	mutex_destroy(&ad7949_adc->lock);
-	regulator_disable(ad7949_adc->vref);
+	if (ad7949_adc->vref)
+		regulator_disable(ad7949_adc->vref);
 
 	return 0;
 }
-- 
1.9.1


^ permalink raw reply	[flat|nested] 13+ messages in thread
* [PATCH 2/6] dt-bindings: iio: ad7949: Add adi,reference-select
@ 2019-05-01 19:30 Adam Michaelis
  0 siblings, 0 replies; 13+ messages in thread
From: Adam Michaelis @ 2019-05-01 19:30 UTC (permalink / raw)
  To: lars, michael.hennerich, jic23, knaack.h, pmeerw, linux-iio,
	linux-kernel, robh+dt, mark.rutland, charles-antoine.couret,
	devicetree
  Cc: Clayton Shotwell, Brandon Maier

From d228a1a119e33aff91f481fb8ab301a027b5a4ac Mon Sep 17 00:00:00 2001
From: Adam Michaelis <adam.michaelis@rockwellcollins.com>
Date: Thu, 25 Apr 2019 15:22:00 -0500
Subject: [PATCH 2/6] dt-bindings: iio: ad7949: Add adi,reference-select

Adding optional parameter to AD7949 to specify the source for the
reference voltage signal. Default value is maintaned with option '6' to
match previous version of driver.

Signed-off-by: Adam Michaelis <adam.michaelis@rockwellcollins.com>
---
Sorry about the re-sends - GMail inserted HTML on me and it bounced from vger.
---
 .../devicetree/bindings/iio/adc/ad7949.txt         | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/iio/adc/ad7949.txt
b/Documentation/devicetree/bindings/iio/adc/ad7949.txt
index c7f5057356b1..14ee9a2cb2a5 100644
--- a/Documentation/devicetree/bindings/iio/adc/ad7949.txt
+++ b/Documentation/devicetree/bindings/iio/adc/ad7949.txt
@@ -6,11 +6,29 @@ Required properties:
  * "adi,ad7682"
  * "adi,ad7689"
  - reg: spi chip select number for the device
- - vref-supply: The regulator supply for ADC reference voltage

-Example:
+Optional properties:
+ - adi,reference-select: Select the reference voltage source to use
+ when converting the input voltages. Valid values are:
+   0: Internal 2.5V reference; temperature sensor enabled
+   1: Internal 4.096V reference; temperature sensor enabled
+   2: External reference, temperature sensor enabled, no buffer
+   3: External reference, temperature sensor enabled, buffer enabled
+   6: External reference, temperature sensor disabled, no buffer
+   7: External reference, temperature sensor disabled, buffer enabled
+ - vref-supply: The regulator supply for ADC reference voltage. Required
+ if external reference selected by 'adi,reference-select'.
+
+Examples:
 adc@0 {
  compatible = "adi,ad7949";
  reg = <0>;
+ adi,reference-select = <2>;
  vref-supply = <&vdd_supply>;
 };
+
+adc@0 {
+ compatible = "adi,ad7949";
+ reg = <0>;
+ adi,reference-select = <0>;
+};
-- 
1.9.1

^ permalink raw reply	[flat|nested] 13+ messages in thread

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Thread overview: 13+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-05-01 21:16 [PATCH 1/6] iio: ad7949: Support internal Vref Adam Michaelis
2019-05-01 21:16 ` [PATCH 2/6] dt-bindings: iio: ad7949: Add adi,reference-select Adam Michaelis
2019-05-05 12:22   ` Jonathan Cameron
2019-05-06 19:28     ` Adam Michaelis
2019-05-07 18:21     ` Adam Michaelis
2019-05-11 10:38       ` Jonathan Cameron
2019-05-13 14:51         ` [External] " Adam Michaelis
2019-05-01 21:17 ` [PATCH 3/6] iio: ad7949: Support configuration read-back Adam Michaelis
2019-05-01 21:17 ` [PATCH 4/6] dt-bindings: iio: ad7949: Add cfg-readback option Adam Michaelis
2019-05-01 21:17 ` [PATCH 5/6] iio: ad7949: Fix SPI interfacing for 14-bit messages Adam Michaelis
2019-05-01 21:17 ` [PATCH 6/6] iio: ad7949: Fix dummy read cycle placement Adam Michaelis
2019-05-02  6:30 ` [PATCH 1/6] iio: ad7949: Support internal Vref Couret Charles-Antoine
  -- strict thread matches above, loose matches on Subject: below --
2019-05-01 19:30 [PATCH 2/6] dt-bindings: iio: ad7949: Add adi,reference-select Adam Michaelis

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