Previously the driver would revert to internal supply if the
external supply couldn't be found. This had multiple problems:
- it caused silently ignored errors when a regulator was intended
to be supplied, but was not specified correctly.
- if CONFIG_REGULATOR is disabled, regulator_get() will always
return a dummy regulator, which caused a device to always use
the external vref mode, even though there is none.
This patch addresses the issue by adding a platform data structure,
containing a boolean field use_external_ref. If the platform data
structure is present and if that boolean is set, the external vref
is used; otherwise the internal vref is used.
In the case where an external vref is wanted but regulator_get()
fails, the driver no longer reverts to using the internal vref,
but returns an error instead.
Signed-off-by: Paul Cercueil <paul.cercueil@xxxxxxxxxx>
---
drivers/iio/dac/ad5064.c | 26 +++++++++++++++++---------
include/linux/platform_data/ad5064.h | 21 +++++++++++++++++++++
2 files changed, 38 insertions(+), 9 deletions(-)
create mode 100644 include/linux/platform_data/ad5064.h
diff --git a/drivers/iio/dac/ad5064.c b/drivers/iio/dac/ad5064.c
index f03b92f..fbb836a 100644
--- a/drivers/iio/dac/ad5064.c
+++ b/drivers/iio/dac/ad5064.c
@@ -2,7 +2,7 @@
* AD5024, AD5025, AD5044, AD5045, AD5064, AD5064-1, AD5065, AD5628, AD5629R,
* AD5648, AD5666, AD5668, AD5669R Digital to analog converters driver
*
- * Copyright 2011 Analog Devices Inc.
+ * Copyright 2011, 2014 Analog Devices Inc.
*
* Licensed under the GPL-2.
*/
@@ -21,6 +21,8 @@
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
+#include <linux/platform_data/ad5064.h>
+
#define AD5064_MAX_DAC_CHANNELS 8
#define AD5064_MAX_VREFS 4
@@ -441,6 +443,7 @@ static const char * const ad5064_vref_name(struct ad5064_state *st,
static int ad5064_probe(struct device *dev, enum ad5064_type type,
const char *name, ad5064_write_func write)
{
+ struct ad5064_platform_data *pdata = dev->platform_data;
struct iio_dev *indio_dev;
struct ad5064_state *st;
unsigned int midscale;
@@ -461,11 +464,20 @@ static int ad5064_probe(struct device *dev, enum ad5064_type type,
for (i = 0; i < ad5064_num_vref(st); ++i)
st->vref_reg[i].supply = ad5064_vref_name(st, i);
- ret = devm_regulator_bulk_get(dev, ad5064_num_vref(st),
- st->vref_reg);
- if (ret) {
- if (!st->chip_info->internal_vref)
+ if (pdata && pdata->use_external_ref) {
+ ret = devm_regulator_bulk_get(dev, ad5064_num_vref(st),
+ st->vref_reg);
+ if (ret)
return ret;
+ ret = regulator_bulk_enable(ad5064_num_vref(st), st->vref_reg);
+ if (ret)
+ return ret;
+ } else {
+ if (!st->chip_info->internal_vref) {
+ dev_err(dev, "No vref available\n");
+ return -ENXIO;
+ }
+
st->use_internal_vref = true;
ret = ad5064_write(st, AD5064_CMD_CONFIG, 0,
AD5064_CONFIG_INT_VREF_ENABLE, 0);
@@ -474,10 +486,6 @@ static int ad5064_probe(struct device *dev, enum ad5064_type type,
ret);
return ret;
}
- } else {
- ret = regulator_bulk_enable(ad5064_num_vref(st), st->vref_reg);
- if (ret)
- return ret;
}
indio_dev->dev.parent = dev;
diff --git a/include/linux/platform_data/ad5064.h b/include/linux/platform_data/ad5064.h
new file mode 100644
index 0000000..8a87a94
--- /dev/null
+++ b/include/linux/platform_data/ad5064.h
@@ -0,0 +1,21 @@
+/*
+ * Analog Devices AD5064 DAC driver
+ *
+ * Copyright 2014 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2.
+ */
+
+#ifndef __IIO_ADC_AD5064_H__
+#define __IIO_ADC_AD5064_H__
+
+/**
+ * struct ad5064_platform_data - AD5064 platform data
+ * @use_external_ref: If set to true use an external voltage reference connected
+ * to the VREF pin, otherwise use the internal reference derived from Vdd.
+ */
+struct ad5064_platform_data {
+ bool use_external_ref;
+};
+
+#endif
--
1.7.10.4
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