On 01/01/14 13:17, Hartmut Knaack wrote:
Jonathan Cameron schrieb:
On 29/12/13 11:49, Hartmut Knaack wrote:
Setting Vref with platform_data is a neat feature, though it is
not essential for operating these devices. So make the use of
platform_data optional and set default value of 1000 mV if
nothing else is defined.
Signed-off-by: Hartmut Knaack <knaack.h@xxxxxx>
Hi Hartmut,
Hi
Why a default of 1V? Does that correspond to anything in
particular?
This makes it easier to calculate your real voltage, since you only
need to multiply with your reference voltage. Another reason: if you
are more interested in the relation of your input in the range
[0V-Vref], you can simply get the per mill value.
Sorry, but I'm not going to take this as whilst I can see how it
is useful for your use case, it would introduce a new non standard
interface.
Whilst the way this is set here is clunky there is a need for this
voltage to be supplied in some fashion. Now we'd do it via a
regulator to give us nice standard device tree bindings and to
allow for less simplistic hardware configurations.
So lets say we convert this to use a regulator, is there still a
reason why one might want a default value?
I'm not aware of the current state of the device tree implementation
at the moment. My intention is to also be able to use this driver
without the need of compiling a custom kernel (so to use the
distribution of choice out of the box).
Then it needs to be device tree enabled and the configuration done
via that.
Jonathan
---
diff --git a/drivers/staging/iio/adc/ad799x_core.c b/drivers/staging/iio/adc/ad799x_core.c
index 9428be8..e32a555 100644
--- a/drivers/staging/iio/adc/ad799x_core.c
+++ b/drivers/staging/iio/adc/ad799x_core.c
@@ -545,10 +545,12 @@ static int ad799x_probe(struct i2c_client *client,
/* TODO: Add pdata options for filtering and bit delay */
- if (!pdata)
- return -EINVAL;
-
- st->int_vref_mv = pdata->vref_mv;
+ if ((!pdata) || (!pdata->vref_mv)) {
+ dev_warn(&client->dev,
+ "No platform data found, setting Vref to 1000 mV\n");
+ st->int_vref_mv = 1000;
+ } else
+ st->int_vref_mv = pdata->vref_mv;
st->reg = devm_regulator_get(&client->dev, "vcc");
if (!IS_ERR(st->reg)) {
--
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