staging:iio:ad7291: Rework regulator handling

Add platform_data for the driver which allows to specify whether an external
reference voltage is used or not. It is not possible to use the return value of
regulator_get() for this since the regulator framework is able to return a dummy
regulator in case no regulator has been specified. In this case the driver will
always get a valid regulator, no matter if it has been specified or not.  Also
make the regulator non-optional if platform_data states that an external
reference voltage should be used.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

diff --git a/drivers/staging/iio/adc/ad7291.c b/drivers/staging/iio/adc/ad7291.c
index c2709d6..3fc79e5 100644 (file)
--- a/drivers/staging/iio/adc/ad7291.c
+++ b/drivers/staging/iio/adc/ad7291.c
@@ -21,6 +21,8 @@
 #include <linux/iio/sysfs.h>
 #include <linux/iio/events.h>
 
+#include "ad7291.h"
+
 /*
  * Simplified handling
  *
@@ -76,7 +78,6 @@
 struct ad7291_chip_info {
        struct i2c_client       *client;
        struct regulator        *reg;
-       u16                     int_vref_mv;
        u16                     command;
        u16                     c_mask; /* Active voltage channels for events */
        struct mutex            state_lock;
@@ -445,7 +446,15 @@ static int ad7291_read_raw(struct iio_dev *indio_dev,
        case IIO_CHAN_INFO_SCALE:
                switch (chan->type) {
                case IIO_VOLTAGE:
-                       *val = chip->int_vref_mv;
+                       if (chip->reg) {
+                               int vref;
+                               vref = regulator_get_voltage(chip->reg);
+                               if (vref < 0)
+                                       return vref;
+                               *val = vref / 1000;
+                       } else {
+                               *val = 2500;
+                       }
                        *val2 = AD7291_BITS;
                        return IIO_VAL_FRACTIONAL_LOG2;
                case IIO_TEMP:
@@ -513,9 +522,10 @@ static const struct iio_info ad7291_info = {
 static int ad7291_probe(struct i2c_client *client,
                const struct i2c_device_id *id)
 {
+       struct ad7291_platform_data *pdata = client->dev.platform_data;
        struct ad7291_chip_info *chip;
        struct iio_dev *indio_dev;
-       int ret = 0, voltage_uv = 0;
+       int ret = 0;
 
        indio_dev = iio_device_alloc(sizeof(*chip));
        if (indio_dev == NULL) {
@@ -524,12 +534,14 @@ static int ad7291_probe(struct i2c_client *client,
        }
        chip = iio_priv(indio_dev);
 
-       chip->reg = regulator_get(&client->dev, "vcc");
-       if (!IS_ERR(chip->reg)) {
+       if (pdata && pdata->use_external_ref) {
+               chip->reg = regulator_get(&client->dev, "vref");
+               if (IS_ERR(chip->reg))
+                       goto error_free;
+
                ret = regulator_enable(chip->reg);
                if (ret)
                        goto error_put_reg;
-               voltage_uv = regulator_get_voltage(chip->reg);
        }
 
        mutex_init(&chip->state_lock);
@@ -542,12 +554,8 @@ static int ad7291_probe(struct i2c_client *client,
                        AD7291_T_SENSE_MASK | /* Tsense always enabled */
                        AD7291_ALERT_POLARITY; /* set irq polarity low level */
 
-       if (voltage_uv) {
-               chip->int_vref_mv = voltage_uv / 1000;
+       if (pdata && pdata->use_external_ref)
                chip->command |= AD7291_EXT_REF;
-       } else {
-               chip->int_vref_mv = 2500; /* Build-in ref */
-       }
 
        indio_dev->name = id->name;
        indio_dev->channels = ad7291_channels;
@@ -590,12 +598,12 @@ error_unreg_irq:
        if (client->irq)
                free_irq(client->irq, indio_dev);
 error_disable_reg:
-       if (!IS_ERR(chip->reg))
+       if (chip->reg)
                regulator_disable(chip->reg);
 error_put_reg:
-       if (!IS_ERR(chip->reg))
+       if (chip->reg)
                regulator_put(chip->reg);
-
+error_free:
        iio_device_free(indio_dev);
 error_ret:
        return ret;
@@ -611,7 +619,7 @@ static int ad7291_remove(struct i2c_client *client)
        if (client->irq)
                free_irq(client->irq, indio_dev);
 
-       if (!IS_ERR(chip->reg)) {
+       if (chip->reg) {
                regulator_disable(chip->reg);
                regulator_put(chip->reg);
        }

diff --git a/drivers/staging/iio/adc/ad7291.h b/drivers/staging/iio/adc/ad7291.h
new file mode 100644 (file)
index 0000000..bbd89fa
--- /dev/null
+++ b/drivers/staging/iio/adc/ad7291.h
@@ -0,0 +1,12 @@
+#ifndef __IIO_AD7291_H__
+#define __IIO_AD7291_H__
+
+/**
+ * struct ad7291_platform_data - AD7291 platform data
+ * @use_external_ref: Whether to use an external or internal reference voltage
+ */
+struct ad7291_platform_data {
+       bool use_external_ref;
+};
+
+#endif