From 1fc12b05895ea50386f0e666f84053f0c8307943 Mon Sep 17 00:00:00 2001 From: Douglas Anderson Date: Tue, 20 Nov 2018 09:52:54 -0800 Subject: regulator: core: Avoid propagating to supplies when possible When we called regulator_enable() on a regulator we'd end up propagating that call all the way up the chain every time. This is a bit of a waste of time. A child regulator already refcounts its own enables so it should avoid passing on to its parent unless the refcount transitioned between 0 and 1. Historically this hasn't been a huge problem since we skipped dealing with enable for always-on regulators. In a previous patch, however, we removed the always-on optimization. On one system, the debugfs regulator_summary was now showing a "use_count" of 33 for a top-level regulator. Let's implement this optimization. This turns out to be fairly trivial with the recent reorganization of the regulator core. NOTE: as part of this patch I'll make "always-on" regulators start with a use count of 1. This keeps the counts clean when recursively resolving regulators. ALSO NOTE: this commit also contains somewhat of a bug fix to regulator_force_disable(). It was incorrectly looping over "rdev->open_count" when it should have been looping over use_count. We have to touch that code anyway (since we should no longer loop at all), so we'll fix it together in one patch. Also: since this comes after commit f8702f9e4aa7 ("regulator: core: Use ww_mutex for regulators locking") we can now move to use _regulator_disable() for our supply and keep it in the lock. Signed-off-by: Douglas Anderson Signed-off-by: Mark Brown --- drivers/regulator/core.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) (limited to 'drivers/regulator/core.c') diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index 26a0c523ed86..03a03763457c 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -1822,6 +1822,7 @@ static int regulator_resolve_supply(struct regulator_dev *rdev) rdev->supply = NULL; return ret; } + rdev->use_count = 1; } return 0; @@ -2491,7 +2492,7 @@ static int _regulator_enable(struct regulator *regulator) lockdep_assert_held_once(&rdev->mutex.base); - if (rdev->supply) { + if (rdev->use_count == 0 && rdev->supply) { ret = _regulator_enable(rdev->supply); if (ret < 0) return ret; @@ -2539,7 +2540,7 @@ err_consumer_disable: _regulator_handle_consumer_disable(regulator); err_disable_supply: - if (rdev->supply) + if (rdev->use_count == 0 && rdev->supply) _regulator_disable(rdev->supply); return ret; @@ -2648,7 +2649,7 @@ static int _regulator_disable(struct regulator *regulator) if (ret == 0 && rdev->coupling_desc.n_coupled > 1) ret = regulator_balance_voltage(rdev, PM_SUSPEND_ON); - if (ret == 0 && rdev->supply) + if (ret == 0 && rdev->use_count == 0 && rdev->supply) ret = _regulator_disable(rdev->supply); return ret; @@ -2733,11 +2734,10 @@ int regulator_force_disable(struct regulator *regulator) ret = drms_uA_update(rdev); } - regulator_unlock_dependent(rdev, &ww_ctx); + if (rdev->use_count != 0 && rdev->supply) + _regulator_disable(rdev->supply); - if (rdev->supply) - while (rdev->open_count--) - regulator_disable(rdev->supply); + regulator_unlock_dependent(rdev, &ww_ctx); return ret; } -- cgit