linux/drivers/opp/core.c, branch v5.7

opp: Manage empty OPP tables with clk handle

2020-04-13T10:44:55Z

With OPP core now supporting DVFS for IO devices, we have instances of IO devices (same IP block) which require an OPP on some platforms/SoCs while just needing to scale the clock on some others. In order to avoid conditional code in every driver which supports such devices (to check for availability of OPPs and then deciding to do either dev_pm_opp_set_rate() or clk_set_rate()) add support to manage empty OPP tables with a clk handle. This makes dev_pm_opp_set_rate() equivalent of a clk_set_rate() for devices with just a clk and no OPPs specified, and makes dev_pm_opp_set_rate(0) bail out without throwing an error. Signed-off-by: Rajendra Nayak Signed-off-by: Viresh Kumar

opp: Replace list_kref with a local counter

2019-12-10T10:27:00Z

A kref or refcount isn't the right tool to be used here for counting number of devices that are sharing the static OPPs created for the OPP table. For example, we are reinitializing the kref again, after it reaches a value of 0 and frees the resources, if the static OPPs get added for the same OPP table structure (as the OPP table structure was never freed). That is messy and very unclear. This patch makes parsed_static_opps an unsigned integer and uses it to count the number of users of the static OPPs. The increment and decrement to parsed_static_opps is done under opp_table->lock now to make sure no races are possible if the OPP table is getting added and removed in parallel (which doesn't happen in practice, but can in theory). Signed-off-by: Viresh Kumar

PM / OPP: Support adjusting OPP voltages at runtime

2019-11-11T04:57:15Z

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 derived from [1] submitted by Stephen. [1] https://lore.kernel.org/patchwork/patch/599279/ Signed-off-by: Stephen Boyd [Roger Lu: Changed to rcu less implementation] Signed-off-by: Roger Lu [s.nawrocki@samsung.com: added handling of OPP min/max voltage] Signed-off-by: Sylwester Nawrocki Signed-off-by: Viresh Kumar

opp: core: Revert "add regulators enable and disable"

2019-10-21T02:28:12Z

All the drivers, which use the OPP framework control regulators, which are already enabled. Typically those regulators are also system critical, due to providing power to CPU core or system buses. It turned out that there are cases, where calling regulator_enable() on such boot-enabled regulator has side-effects and might change its initial voltage due to performing initial voltage balancing without all restrictions from the consumers. Until this issue becomes finally solved in regulator core, avoid calling regulator_enable()/disable() from the OPP framework. This reverts commit 7f93ff73f7c8c8bfa6be33bcc16470b0b44682aa. Signed-off-by: Marek Szyprowski Reviewed-by: Mark Brown Signed-off-by: Viresh Kumar

opp: core: add regulators enable and disable

2019-07-26T07:55:52Z

Add enable regulators to dev_pm_opp_set_regulators() and disable regulators to dev_pm_opp_put_regulators(). Even if bootloader leaves regulators enabled, they should be enabled in kernel in order to increase the reference count. Signed-off-by: Kamil Konieczny Signed-off-by: Viresh Kumar

opp: Don't decrement uninitialized list_kref

2019-07-26T07:55:52Z

The list_kref was added for static OPPs and to track their users. The kref is initialized while the static OPPs are added, but removed unconditionally even if the static OPPs were never added. This causes refcount mismatch warnings currently. Fix that by always initializing the kref when the OPP table is first initialized. The refcount is later incremented only for the second user onwards. Fixes: d0e8ae6c26da ("OPP: Create separate kref for static OPPs list") Reported-by: Rajendra Nayak Signed-off-by: Viresh Kumar

opp: Add dev_pm_opp_find_level_exact()

2019-07-26T07:54:59Z

Since the performance states in the OPP table are unique, implement a dev_pm_opp_find_level_exact() in order to be able to fetch a specific OPP. Signed-off-by: Niklas Cassel [ Viresh: Updated commit log ] Signed-off-by: Viresh Kumar

opp: Return genpd virtual devices from dev_pm_opp_attach_genpd()

2019-07-26T07:53:31Z

The cpufreq drivers don't need to do runtime PM operations on the virtual devices returned by dev_pm_domain_attach_by_name() and so the virtual devices weren't shared with the callers of dev_pm_opp_attach_genpd() earlier. But the IO device drivers would want to do that. This patch updates the prototype of dev_pm_opp_attach_genpd() to accept another argument to return the pointer to the array of genpd virtual devices. Reported-by: Rajendra Nayak Tested-by: Rajendra Nayak Signed-off-by: Viresh Kumar

opp: Not all power-domains are scalable

2019-07-26T07:53:31Z

A device may have multiple power-domains and not all of them may be scalable (i.e. support performance states). But dev_pm_opp_attach_genpd() doesn't take that into account currently. Fix that by not verifying the names argument with "power-domain-names" DT property and finding the index into the required-opps array. The names argument will anyway get verified later on when we call dev_pm_domain_attach_by_name(). Fixes: 6319aee10e53 ("opp: Attach genpds to devices from within OPP core") Reported-by: Rajendra Nayak Tested-by: Rajendra Nayak Signed-off-by: Viresh Kumar

Merge branch 'opp/linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm

2019-06-26T08:53:57Z

Pull operating performance points (OPP) framework changes for v5.3 from Viresh Kumar: "This pull request contains: - OPP core changes to support a wider range of devices, like IO devices (Rajendra Nayak and Stehpen Boyd). - Fixes around genpd_virt_devs (Viresh Kumar). - Fix for platform with set_opp() callback (Dmitry Osipenko)." * 'opp/linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm: opp: Don't use IS_ERR on invalid supplies opp: Make dev_pm_opp_set_rate() handle freq = 0 to drop performance votes opp: Don't overwrite rounded clk rate opp: Allocate genpd_virt_devs from dev_pm_opp_attach_genpd() opp: Attach genpds to devices from within OPP core