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Subject[PATCH] ASoC: cx20442: Don't ignore regulator_get() errors.
Date
In its current shape, the driver just ignores errors returned by
regulator_get() at component_probe(). This doesn't hurt on Amstrad
Delta board as long as it registers the codec device at late_initcall,
when the regulator which depends on basic-mmio-gpio device (probed as
late as at dev_initcall) is already available. Otherwise the driver
may end up trying to control a codec which is not powered up.

Remove that dependency on initialization order by handling the error.
If the regulator is not yet available and -ENODEV is returned, convert
it to -EPROBE_DEFER to get another chance.

Signed-off-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>
---
Created and tested on linux-4.18-rc1

sound/soc/codecs/cx20442.c | 23 +++++++++++++++++++++--
1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/sound/soc/codecs/cx20442.c b/sound/soc/codecs/cx20442.c
index 07dd33b09596..ab174b5114dc 100644
--- a/sound/soc/codecs/cx20442.c
+++ b/sound/soc/codecs/cx20442.c
@@ -362,8 +362,27 @@ static int cx20442_component_probe(struct snd_soc_component *component)
return -ENOMEM;

cx20442->por = regulator_get(component->dev, "POR");
- if (IS_ERR(cx20442->por))
- dev_warn(component->dev, "failed to get the regulator");
+ if (IS_ERR(cx20442->por)) {
+ int err = PTR_ERR(cx20442->por);
+
+ dev_warn(component->dev, "failed to get POR supply (%d)", err);
+ /*
+ * When running on a non-dt platform and requested regulator
+ * is not available, regulator_get() never returns
+ * -EPROBE_DEFER as it is not able to justify if the regulator
+ * may still appear later. On the other hand, the board can
+ * still set full constraints flag at late_initcall in order
+ * to instruct regulator_get() to return a dummy one if
+ * sufficient. Hence, if we get -ENODEV here, let's convert
+ * it to -EPROBE_DEFER and wait for the board to decide or
+ * let Deferred Probe infrastructure handle this error.
+ */
+ if (err == -ENODEV)
+ err = -EPROBE_DEFER;
+ kfree(cx20442);
+ return err;
+ }
+
cx20442->tty = NULL;

snd_soc_component_set_drvdata(component, cx20442);
--
2.16.4
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