Dear Stephen Boyd, This patch is derived from [1]. Please kindly shares the suggestion to us. Thanks very much. [1]: https://lore.kernel.org/patchwork/patch/599279/ Dear Viresh, I followed _opp_set_availability() coding style to refine dev_pm_opp_adjust_voltage() from this patch. Is this refinement suitable for OPP core? Thanks a lot. On Mon, 2019-05-20 at 12:47 +0800, Viresh Kumar wrote: > On 16-05-19, 17:08, Andrew-sh.Cheng wrote: > > From: Stephen Boyd <sboyd@xxxxxxxxxxxxxx> > > > > On some SoCs the Adaptive Voltage Scaling (AVS) technique is > > employed to optimize the operating voltage of a device. At a > > given frequency, the hardware monitors dynamic factors and either > > makes a suggestion for how much to adjust a voltage for the > > current frequency, or it automatically adjusts the voltage > > without software intervention. Add an API to the OPP library for > > the former case, so that AVS type devices can update the voltages > > for an OPP when the hardware determines the voltage should > > change. The assumption is that drivers like CPUfreq or devfreq > > will register for the OPP notifiers and adjust the voltage > > according to suggestions that AVS makes. > > > > This patch is devired from [1] submitted by Stephen. > > [1] https://lore.kernel.org/patchwork/patch/599279/ > > > > Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx> > > Signed-off-by: Roger Lu <roger.lu@xxxxxxxxxxxx> > > --- > > drivers/opp/core.c | 78 ++++++++++++++++++++++++++++++++++++++++++++++++++ > > include/linux/pm_opp.h | 11 +++++++ > > 2 files changed, 89 insertions(+) > > This is an rcu implementation which got removed long back from OPP core. Please > align this with the latest changes. > /** * dev_pm_opp_adjust_voltage() - helper to change the voltage of an OPP * @dev: device for which we do this operation * @freq: OPP frequency to adjust voltage of * @u_volt: new OPP voltage * * Return: -EINVAL for bad pointers, -ENOMEM if no memory available for the * copy operation, returns 0 if no modifcation was done OR modification was * successful. */ int dev_pm_opp_adjust_voltage(struct device *dev, unsigned long freq, unsigned long u_volt) { struct opp_table *opp_table; struct dev_pm_opp *tmp_opp, *opp = ERR_PTR(-ENODEV); int r = 0; /* Find the opp_table */ opp_table = _find_opp_table(dev); if (IS_ERR(opp_table)) { r = PTR_ERR(opp_table); dev_warn(dev, "%s: Device OPP not found (%d)\n", __func__, r); return r; } mutex_lock(&opp_table->lock); /* Do we have the frequency? */ list_for_each_entry(tmp_opp, &opp_table->opp_list, node) { if (tmp_opp->rate == freq) { opp = tmp_opp; break; } } if (IS_ERR(opp)) { r = PTR_ERR(opp); goto adjust_unlock; } /* Is update really needed? */ if (opp->supplies->u_volt == u_volt) goto adjust_unlock; opp->supplies->u_volt = u_volt; dev_pm_opp_get(opp); mutex_unlock(&opp_table->lock); /* Notify the voltage change of the OPP */ blocking_notifier_call_chain(&opp_table->head, OPP_EVENT_ADJUST_VOLTAGE, opp); dev_pm_opp_put(opp); goto adjust_put_table; adjust_unlock: mutex_unlock(&opp_table->lock); adjust_put_table: dev_pm_opp_put_opp_table(opp_table); return r; } Sincerely, Roger Lu.
