On Ubuntu systems with CONFIG_REGULATOR enabled, the lm90 driver fails to load
with an error mesage such as
i2c 1-0018: Driver lm90 requests probe deferral
This is a result of commit 3e0f964f2ad (hwmon: (lm90) Add power control)
which adds mandatory regulator support to the lm90 driver. On non-dt systems
with CONFIG_REGULATOR enabled, this fails if regulators are not fully
specified. This is the case on a standard PC system.
To fix the problem, make the regulator on non-dt systems optional.
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
---
drivers/hwmon/lm90.c | 30 ++++++++++++++++++++----------
1 file changed, 20 insertions(+), 10 deletions(-)
diff --git a/drivers/hwmon/lm90.c b/drivers/hwmon/lm90.c
index bc41682..51932da 100644
--- a/drivers/hwmon/lm90.c
+++ b/drivers/hwmon/lm90.c
@@ -1520,15 +1520,23 @@ static int lm90_probe(struct i2c_client *client,
struct regulator *regulator;
int err;
+ /*
+ * On non-dt systems, the regulator subsystem expects regulators
+ * to be fully constrained if enabled, which is an unreasonable
+ * expectation from the perspective of this driver.
+ * Therefore, ignore errors on such systems.
+ */
regulator = devm_regulator_get(dev, "vcc");
- if (IS_ERR(regulator))
- return PTR_ERR(regulator);
-
- err = regulator_enable(regulator);
- if (err < 0) {
- dev_err(&client->dev,
- "Failed to enable regulator: %d\n", err);
- return err;
+ if (IS_ERR(regulator)) {
+ if (IS_ENABLED(CONFIG_OF))
+ return PTR_ERR(regulator);
+ } else {
+ err = regulator_enable(regulator);
+ if (err < 0) {
+ dev_err(&client->dev,
+ "Failed to enable regulator: %d\n", err);
+ return err;
+ }
}
data = devm_kzalloc(&client->dev, sizeof(struct lm90_data), GFP_KERNEL);
@@ -1621,7 +1629,8 @@ exit_remove_files:
lm90_remove_files(client, data);
exit_restore:
lm90_restore_conf(client, data);
- regulator_disable(data->regulator);
+ if (!IS_ERR_OR_NULL(data->regulator))
+ regulator_disable(data->regulator);
return err;
}
@@ -1633,7 +1642,8 @@ static int lm90_remove(struct i2c_client *client)
hwmon_device_unregister(data->hwmon_dev);
lm90_remove_files(client, data);
lm90_restore_conf(client, data);
- regulator_disable(data->regulator);
+ if (!IS_ERR_OR_NULL(data->regulator))
+ regulator_disable(data->regulator);
return 0;
}
--
1.7.9.7
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