Since commit ea572f816032 ("PM / devfreq: Change return type of
devfreq_set_freq_table()"), all devfreq devices are required to have a
valid freq_table. If freq_table is not provided by the driver, it will
be filled in by set_freq_table() from the OPPs; if that fails,
devfreq_add_device() will return an error.
However, since commit ab8f58ad72c4 ("PM / devfreq: Set min/max_freq when
adding the devfreq device"), devfreq devices are _also_ required to have
an OPP table, even if they provide freq_table. devfreq_add_device()
requires dev_pm_opp_find_freq_ceil() and dev_pm_opp_find_freq_floor() to
return successfully, specifically to initialize scaling_min/max_freq.
Not all drivers need an OPP table. For example, a driver where all
frequencies are determined dynamically could work by filling out only
freq_table. But with the current code it must call dev_pm_opp_add() on
every freq_table entry to probe successfully.
The offending properties, scaling_min/max_freq, are only necessary if a
device has OPPs; if no OPPs exist at all, OPPs cannot be dynamically
enabled or disabled, so those values have no effect. Thus it is trivial
to restore support for devices with freq_table only and not OPPs -- move
those initializations behind the check for a valid OPP table.
Since get_freq_range() uses scaling_max_freq in a min() expression, it
must be initialized to the maximum possible value. scaling_min_freq is
initialized as well for consistency.
Fixes: ab8f58ad72c4 ("PM / devfreq: Set min/max_freq when adding the devfreq device")
Signed-off-by: Samuel Holland <samuel@xxxxxxxxxxxx>
---
drivers/devfreq/devfreq.c | 36 ++++++++++++++++++++----------------
1 file changed, 20 insertions(+), 16 deletions(-)
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 7a8b022ba456..426e31e6c448 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -835,24 +835,28 @@ struct devfreq *devfreq_add_device(struct device *dev,
mutex_lock(&devfreq->lock);
}
- devfreq->scaling_min_freq = find_available_min_freq(devfreq);
- if (!devfreq->scaling_min_freq) {
- mutex_unlock(&devfreq->lock);
- err = -EINVAL;
- goto err_dev;
- }
-
- devfreq->scaling_max_freq = find_available_max_freq(devfreq);
- if (!devfreq->scaling_max_freq) {
- mutex_unlock(&devfreq->lock);
- err = -EINVAL;
- goto err_dev;
- }
-
- devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev);
devfreq->opp_table = dev_pm_opp_get_opp_table(dev);
- if (IS_ERR(devfreq->opp_table))
+ if (IS_ERR(devfreq->opp_table)) {
devfreq->opp_table = NULL;
+ devfreq->scaling_min_freq = 0;
+ devfreq->scaling_max_freq = ULONG_MAX;
+ } else {
+ devfreq->scaling_min_freq = find_available_min_freq(devfreq);
+ if (!devfreq->scaling_min_freq) {
+ mutex_unlock(&devfreq->lock);
+ err = -EINVAL;
+ goto err_dev;
+ }
+
+ devfreq->scaling_max_freq = find_available_max_freq(devfreq);
+ if (!devfreq->scaling_max_freq) {
+ mutex_unlock(&devfreq->lock);
+ err = -EINVAL;
+ goto err_dev;
+ }
+
+ devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev);
+ }
atomic_set(&devfreq->suspend_count, 0);
--
2.31.1
