staging:iio:adc:ad7291: Add regulator, reference voltage and scale handling

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/iio/adc/ad7291.c

@@ -14,6 +14,8 @@
 #include <linux/i2c.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
+#include <linux/regulator/consumer.h>
+#include <linux/err.h>
 
 #include "../iio.h"
 #include "../sysfs.h"
@@ -27,8 +29,8 @@
  *
  * The noise-delayed bit as per datasheet suggestion is always enabled.
  *
- * Extref control should be based on regulator provision - not handled.
  */
+
 /*
  * AD7291 registers definition
  */
@@ -61,16 +63,21 @@
  * AD7291 value masks
  */
 #define AD7291_CHANNEL_MASK		0xF000
+#define AD7291_BITS			12
 #define AD7291_VALUE_MASK		0xFFF
 #define AD7291_T_VALUE_SIGN		0x400
 #define AD7291_T_VALUE_FLOAT_OFFSET	2
 #define AD7291_T_VALUE_FLOAT_MASK	0x2
 
+#define AD7291_BITS			12
+
 struct ad7291_chip_info {
-	struct i2c_client *client;
-	u16 command;
-	u8 c_mask;	/* Active voltage channels for events */
-	struct mutex state_lock;
+	struct i2c_client	*client;
+	struct regulator	*reg;
+	u16			int_vref_mv;
+	u16			command;
+	u8			c_mask;	/* Active voltage channels for events */
+	struct mutex 		state_lock;
 };
 
 static int ad7291_i2c_read(struct ad7291_chip_info *chip, u8 reg, u16 *data)
@@ -420,6 +427,7 @@ static int ad7291_read_raw(struct iio_dev *indio_dev,
 {
 	int ret;
 	struct ad7291_chip_info *chip = iio_priv(indio_dev);
+	unsigned int scale_uv;
 	u16 regval;
 	s16 signval;
 
@@ -471,6 +479,11 @@ static int ad7291_read_raw(struct iio_dev *indio_dev,
 			signval = (s16)((swab16((u16)ret) & 0x0FFF) << 4) >> 4;
 			*val = signval;
 			return IIO_VAL_INT;
+	case (1 << IIO_CHAN_INFO_SCALE_SHARED):
+		scale_uv = (chip->int_vref_mv * 1000) >> AD7291_BITS;
+		*val =  scale_uv / 1000;
+		*val2 = (scale_uv % 1000) * 1000;
+		return IIO_VAL_INT_PLUS_MICRO;
 	default:
 		return -EINVAL;
 	}
@@ -479,6 +492,7 @@ static int ad7291_read_raw(struct iio_dev *indio_dev,
 #define AD7291_VOLTAGE_CHAN(_chan)					\
 {									\
 	.type = IIO_VOLTAGE,						\
+	.info_mask = (1 << IIO_CHAN_INFO_SCALE_SHARED),			\
 	.indexed = 1,							\
 	.channel = _chan,						\
 	.event_mask = IIO_EV_BIT(IIO_EV_TYPE_THRESH, IIO_EV_DIR_RISING)|\
@@ -524,7 +538,7 @@ static int __devinit ad7291_probe(struct i2c_client *client,
 {
 	struct ad7291_chip_info *chip;
 	struct iio_dev *indio_dev;
-	int ret = 0;
+	int ret = 0, voltage_uv = 0;
 
 	indio_dev = iio_allocate_device(sizeof(*chip));
 	if (indio_dev == NULL) {
@@ -532,6 +546,15 @@ static int __devinit ad7291_probe(struct i2c_client *client,
 		goto error_ret;
 	}
 	chip = iio_priv(indio_dev);
+
+	chip->reg = regulator_get(&client->dev, "vcc");
+	if (!IS_ERR(chip->reg)) {
+		ret = regulator_enable(chip->reg);
+		if (ret)
+			goto error_put_reg;
+		voltage_uv = regulator_get_voltage(chip->reg);
+	}
+
 	mutex_init(&chip->state_lock);
 	/* this is only used for device removal purposes */
 	i2c_set_clientdata(client, indio_dev);
@@ -540,6 +563,13 @@ static int __devinit ad7291_probe(struct i2c_client *client,
 	/* Tsense always enabled */
 	chip->command = AD7291_NOISE_DELAY | AD7291_T_SENSE_MASK;
 
+	if (voltage_uv) {
+		chip->int_vref_mv = voltage_uv / 1000;
+		chip->command |= AD7291_EXT_REF;
+	} else {
+		chip->int_vref_mv = 2500; /* Build-in ref */
+	}
+
 	indio_dev->name = id->name;
 	indio_dev->channels = ad7291_channels;
 	indio_dev->num_channels = ARRAY_SIZE(ad7291_channels);
@@ -556,7 +586,7 @@ static int __devinit ad7291_probe(struct i2c_client *client,
 					   id->name,
 					   indio_dev);
 		if (ret)
-			goto error_free_dev;
+			goto error_disable_reg;
 
 		/* set irq polarity low level */
 		chip->command |= AD7291_ALERT_POLARITY;
@@ -572,7 +602,7 @@ static int __devinit ad7291_probe(struct i2c_client *client,
 	if (ret)
 		goto error_unreg_irq;
 
-	dev_info(&client->dev, "%s temperature sensor registered.\n",
+	dev_info(&client->dev, "%s ADC registered.\n",
 			 id->name);
 
 	return 0;
@@ -580,7 +610,13 @@ static int __devinit ad7291_probe(struct i2c_client *client,
 error_unreg_irq:
 	if (client->irq)
 		free_irq(client->irq, indio_dev);
-error_free_dev:
+error_disable_reg:
+	if (!IS_ERR(chip->reg))
+		regulator_disable(chip->reg);
+error_put_reg:
+	if (!IS_ERR(chip->reg))
+		regulator_put(chip->reg);
+
 	iio_free_device(indio_dev);
 error_ret:
 	return ret;
@@ -589,9 +625,16 @@ static int __devinit ad7291_probe(struct i2c_client *client,
 static int __devexit ad7291_remove(struct i2c_client *client)
 {
 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
+	struct ad7291_chip_info *chip = iio_priv(indio_dev);
 
 	if (client->irq)
 		free_irq(client->irq, indio_dev);
+
+	if (!IS_ERR(chip->reg)) {
+		regulator_disable(chip->reg);
+		regulator_put(chip->reg);
+	}
+
 	iio_device_unregister(indio_dev);
 
 	return 0;