kernel/linux.git/drivers/regulator/core.c, branch v6.18.37

regulator: core: fix locking in regulator_resolve_supply() error path

2026-06-27T10:06:48+00:00

commit 497330b203d2c59c5ff3fa4c34d14494d7203bc3 upstream. If late enabling of a supply regulator fails in regulator_resolve_supply(), the code currently triggers a lockdep warning: WARNING: drivers/regulator/core.c:2649 at _regulator_put+0x80/0xa0, CPU#6: kworker/u32:4/596 ... Call trace: _regulator_put+0x80/0xa0 (P) regulator_resolve_supply+0x7cc/0xbe0 regulator_register_resolve_supply+0x28/0xb8 as the regulator_list_mutex must be held when calling _regulator_put(). To solve this, simply switch to using regulator_put(). While at it, we should also make sure that no concurrent access happens to our rdev while we clear out the supply pointer. Add appropriate locking to ensure that. While the code in question will be removed altogether in a follow-up commit, I believe it is still beneficial to have this corrected before removal for future reference. Fixes: 36a1f1b6ddc6 ("regulator: core: Fix memory leak in regulator_resolve_supply()") Fixes: 8e5356a73604 ("regulator: core: Clear the supply pointer if enabling fails") Signed-off-by: André Draszik Link: https://patch.msgid.link/20260109-regulators-defer-v2-2-1a25dc968e60@linaro.org Signed-off-by: Mark Brown Signed-off-by: Nazar Kalashnikov Signed-off-by: Greg Kroah-Hartman

regulator: core: Remove regulator supply_name length limit

2026-03-04T12:20:39+00:00

[ Upstream commit e243cdd87b911ce9968b62e4ab2b680dfadc4341 ] When creating the regulator object, associated with a consumer device, the supply_name is string formatted into a statically sized buffer on the stack, then strdup()'ed onto the heap. Not only is the dance on the stack unnecessary, but when the device's name is long we might not fit the constructed supply_name in the fixed 64 byte buffer on the stack. One such case can be seen on the Qualcomm Rb3Gen2 board, where we find a PCIe controller, with a PCIe switch, with a USB controller, with a USB hub, consuming a regulator. In this example the dev->kobj.name itself is 62 characters long. Drop the temporary buffer on the stack and kasprintf() the string directly on the heap, both to simplify the code, and to remove the length limitation. Signed-off-by: Bjorn Andersson Link: https://patch.msgid.link/20260211-regulator-supply-name-length-v1-1-3875541c1576@oss.qualcomm.com Signed-off-by: Mark Brown Signed-off-by: Sasha Levin

regulator: core: move supply check earlier in set_machine_constraints()

2026-02-26T22:59:12+00:00

[ Upstream commit 86a8eeb0e913f4b6a55dabba5122098d4e805e55 ] Since commit 98e48cd9283d ("regulator: core: resolve supply for boot-on/always-on regulators"), set_machine_constraints() can return -EPROBE_DEFER very late, after it has done a lot of work and configuration of the regulator. This means that configuration will happen multiple times for no benefit in that case. Furthermore, this can lead to timing-dependent voltage glitches as mentioned e.g. in commit 8a866d527ac0 ("regulator: core: Resolve supply name earlier to prevent double-init"). We can know that it's going to fail very early, in particular before going through the complete regulator configuration by moving some code around a little. Do so to avoid re-configuring the regulator multiple times, also avoiding the voltage glitches if we can. Fixes: 98e48cd9283d ("regulator: core: resolve supply for boot-on/always-on regulators") Signed-off-by: André Draszik Link: https://patch.msgid.link/20260109-regulators-defer-v2-3-1a25dc968e60@linaro.org Signed-off-by: Mark Brown Signed-off-by: Sasha Levin

regulator: core: Protect regulator_supply_alias_list with regulator_list_mutex

2025-12-18T13:03:25+00:00

[ Upstream commit 0cc15a10c3b4ab14cd71b779fd5c9ca0cb2bc30d ] regulator_supply_alias_list was accessed without any locking in regulator_supply_alias(), regulator_register_supply_alias(), and regulator_unregister_supply_alias(). Concurrent registration, unregistration and lookups can race, leading to: 1 use-after-free if an alias entry is removed while being read, 2 duplicate entries when two threads register the same alias, 3 inconsistent alias mappings observed by consumers. Protect all traversals, insertions and deletions on regulator_supply_alias_list with the existing regulator_list_mutex. Fixes: a06ccd9c3785f ("regulator: core: Add ability to create a lookup alias for supply") Signed-off-by: sparkhuang Reviewed-by: Charles Keepax Link: https://patch.msgid.link/20251127025716.5440-1-huangshaobo3@xiaomi.com Signed-off-by: Mark Brown Signed-off-by: Sasha Levin

regulator: core: disable supply if enabling main regulator fails

2025-12-18T13:02:53+00:00

[ Upstream commit fb1ebb10468da414d57153ddebaab29c38ef1a78 ] For 'always-on' and 'boot-on' regulators, the set_machine_constraints() may enable supply before enabling the main regulator, however if the latter fails, the function returns with an error but the supply remains enabled. When this happens, the regulator_register() function continues on the error path where it puts the supply regulator. Since enabling the supply is not balanced with a disable call, a warning similar to the following gets issued from _regulator_put(): [ 1.603889] WARNING: CPU: 2 PID: 44 at _regulator_put+0x8c/0xa0 [ 1.603908] Modules linked in: [ 1.603926] CPU: 2 UID: 0 PID: 44 Comm: kworker/u16:3 Not tainted 6.18.0-rc4 #0 NONE [ 1.603938] Hardware name: Qualcomm Technologies, Inc. IPQ9574/AP-AL02-C7 (DT) [ 1.603945] Workqueue: async async_run_entry_fn [ 1.603958] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 1.603967] pc : _regulator_put+0x8c/0xa0 [ 1.603976] lr : _regulator_put+0x7c/0xa0 ... [ 1.604140] Call trace: [ 1.604145] _regulator_put+0x8c/0xa0 (P) [ 1.604156] regulator_register+0x2ec/0xbf0 [ 1.604166] devm_regulator_register+0x60/0xb0 [ 1.604178] rpm_reg_probe+0x120/0x208 [ 1.604187] platform_probe+0x64/0xa8 ... In order to avoid this, change the set_machine_constraints() function to disable the supply if enabling the main regulator fails. Fixes: 05f224ca6693 ("regulator: core: Clean enabling always-on regulators + their supplies") Signed-off-by: Gabor Juhos Link: https://patch.msgid.link/20251107-regulator-disable-supply-v1-1-c95f0536f1b5@gmail.com Signed-off-by: Mark Brown Signed-off-by: Sasha Levin

regulator: core: Remove redundant ternary operators

2025-08-28T14:02:51+00:00

For ternary operators in the form of "a ? true : false", if 'a' itself returns a boolean result, the ternary operator can be omitted. Remove redundant ternary operators to clean up the code. Signed-off-by: Liao Yuanhong Message-ID: <20250828122737.43488-1-liaoyuanhong@vivo.com> Signed-off-by: Mark Brown

regulator: core: correct convergence check in regulator_set_voltage()

2025-07-29T13:56:39+00:00

The logic in regulator_set_voltage() which checks for a non-convergence condition on a stepped regulator is flawed. regulator_set_voltage() checks if the error in target voltage has increased or decreased, and returns -EWOULDBLOCK if the error has not decreased enough. The correct non-convergence condition is: new_delta - delta > -rdev->constraints->max_uV_step or equivalently: delta - new_delta < rdev->constraints->max_uV_step But the currently used condition is: new_delta - delta > rdev->constraints->max_uV_step Which may cause an infinite loop if the voltage error doesn't converge. Fix this by correcting the convergence condition. Suggested-by: Jon Hunter Fixes: d511206dc7443 ("regulator: core: repeat voltage setting request for stepped regulators") Signed-off-by: Romain Gantois Link: https://patch.msgid.link/20250729-b4-regulator-stepping-fix-v1-1-3f7b8c55d7d7@bootlin.com Tested-by: Jon Hunter Reviewed-by: Jon Hunter Signed-off-by: Mark Brown

regulator: core: repeat voltage setting request for stepped regulators

2025-07-18T15:17:09+00:00

The regulator_set_voltage() function may exhibit unexpected behavior if the target regulator has a maximum voltage step constraint. With such a constraint, the regulator core may clamp the requested voltage to a lesser value, to ensure that the voltage delta stays under the specified limit. This means that the resulting regulator voltage depends on the current voltage, as well as the requested range, which invalidates the assumption that a repeated request for a specific voltage range will amount to a noop. Considering the case of a regulator with a maximum voltage step constraint of 1V: initial voltage: 2.5V consumer requests 4V expected result: 3.5V resulting voltage: 3.5V consumer requests 4V again expected result: 4V actual result: 3.5V Correct this by repeating attempts to balance the regulator voltage until the result converges. Signed-off-by: Romain Gantois Link: https://patch.msgid.link/20250718-regulator-stepping-v2-1-e28c9ac5d54a@bootlin.com Signed-off-by: Mark Brown

regulator: core: fix NULL dereference on unbind due to stale coupling data

2025-06-29T21:10:41+00:00

Failing to reset coupling_desc.n_coupled after freeing coupled_rdevs can lead to NULL pointer dereference when regulators are accessed post-unbind. This can happen during runtime PM or other regulator operations that rely on coupling metadata. For example, on ridesx4, unbinding the 'reg-dummy' platform device triggers a panic in regulator_lock_recursive() due to stale coupling state. Ensure n_coupled is set to 0 to prevent access to invalid pointers. Signed-off-by: Alessandro Carminati Link: https://patch.msgid.link/20250626083809.314842-1-acarmina@redhat.com Signed-off-by: Mark Brown

regulator: don't compare raw GPIO descriptor pointers

2025-04-09T12:46:58+00:00

There's no API contract saying that two GPIO descriptor pointers obtained with a call to gpiod_get() (or one of the variants), that refer to the same physical GPIO pin, always point to the same structure. Use the dedicated comparator function. Signed-off-by: Bartosz Golaszewski Link: https://patch.msgid.link/20250407-gpiod-is-equal-v1-2-7d85f568ae6e@linaro.org Signed-off-by: Mark Brown