1 files changed, 96 insertions, 1 deletions

diff --git a/drivers/iio/adc/sd_adc_modulator.c b/drivers/iio/adc/sd_adc_modulator.c
index 327cc2097f6c..654b6a38b650 100644
--- a/drivers/iio/adc/sd_adc_modulator.c
+++ b/drivers/iio/adc/sd_adc_modulator.c
@@ -6,11 +6,14 @@
  * Author: Arnaud Pouliquen <arnaud.pouliquen@st.com>.
  */
 
+#include <linux/iio/backend.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/triggered_buffer.h>
 #include <linux/module.h>
 #include <linux/mod_devicetable.h>
 #include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/regulator/consumer.h>
 
 static const struct iio_info iio_sd_mod_iio_info;
 
@@ -24,7 +27,59 @@ static const struct iio_chan_spec iio_sd_mod_ch = {
 	},
 };
 
-static int iio_sd_mod_probe(struct platform_device *pdev)
+struct iio_sd_backend_priv {
+	struct regulator *vref;
+	int vref_mv;
+};
+
+static int iio_sd_mod_enable(struct iio_backend *backend)
+{
+	struct iio_sd_backend_priv *priv = iio_backend_get_priv(backend);
+
+	if (priv->vref)
+		return regulator_enable(priv->vref);
+
+	return 0;
+};
+
+static void iio_sd_mod_disable(struct iio_backend *backend)
+{
+	struct iio_sd_backend_priv *priv = iio_backend_get_priv(backend);
+
+	if (priv->vref)
+		regulator_disable(priv->vref);
+};
+
+static int iio_sd_mod_read(struct iio_backend *backend, struct iio_chan_spec const *chan, int *val,
+			   int *val2, long mask)
+{
+	struct iio_sd_backend_priv *priv = iio_backend_get_priv(backend);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_SCALE:
+		*val = priv->vref_mv;
+		return IIO_VAL_INT;
+
+	case IIO_CHAN_INFO_OFFSET:
+		*val = 0;
+		return IIO_VAL_INT;
+	}
+
+	return -EOPNOTSUPP;
+};
+
+static const struct iio_backend_ops sd_backend_ops = {
+	.enable = iio_sd_mod_enable,
+	.disable = iio_sd_mod_disable,
+	.read_raw = iio_sd_mod_read,
+};
+
+static const struct iio_backend_info sd_backend_info = {
+	.name = "sd-modulator",
+	.ops = &sd_backend_ops,
+};
+
+static int iio_sd_mod_register(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct iio_dev *iio;
@@ -45,6 +100,45 @@ static int iio_sd_mod_probe(struct platform_device *pdev)
 	return devm_iio_device_register(&pdev->dev, iio);
 }
 
+static int iio_sd_mod_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct regulator *vref;
+	struct iio_sd_backend_priv *priv;
+	int ret;
+
+	/* If sd modulator is not defined as an IIO backend device, fallback to legacy */
+	if (!device_property_present(dev, "#io-backend-cells"))
+		return iio_sd_mod_register(pdev);
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	/*
+	 * Get regulator reference if any, but don't enable regulator right now.
+	 * Rely on enable and disable callbacks to manage regulator power.
+	 */
+	vref = devm_regulator_get_optional(dev, "vref");
+	if (IS_ERR(vref)) {
+		if (PTR_ERR(vref) != -ENODEV)
+			return dev_err_probe(dev, PTR_ERR(vref), "Failed to get vref\n");
+	} else {
+		/*
+		 * Retrieve voltage right now, as regulator_get_voltage() provides it whatever
+		 * the state of the regulator.
+		 */
+		ret = regulator_get_voltage(vref);
+		if (ret < 0)
+			return ret;
+
+		priv->vref = vref;
+		priv->vref_mv = ret / 1000;
+	}
+
+	return devm_iio_backend_register(&pdev->dev, &sd_backend_info, priv);
+};
+
 static const struct of_device_id sd_adc_of_match[] = {
 	{ .compatible = "sd-modulator" },
 	{ .compatible = "ads1201" },
@@ -65,3 +159,4 @@ module_platform_driver(iio_sd_mod_adc);
 MODULE_DESCRIPTION("Basic sigma delta modulator");
 MODULE_AUTHOR("Arnaud Pouliquen <arnaud.pouliquen@st.com>");
 MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(IIO_BACKEND);