From 0442aa45f3365bad75d0ce862e7db3143cf9e1de Mon Sep 17 00:00:00 2001 From: Samuel Holland Date: Sat, 3 Apr 2021 16:47:11 -0500 Subject: [PATCH 412/478] PM / devfreq: Do not require devices to have OPPs 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 --- 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 06333d430382..dea2fab64dc7 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); -- 2.35.3