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[91.67.66.34]) by smtp.gmail.com with ESMTPSA id g1-20020a170906538100b007308bebce51sm95062ejo.171.2022.08.25.14.28.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 25 Aug 2022 14:29:00 -0700 (PDT) From: =?utf-8?q?Christian_Kohlsch=C3=BCtter?= To: broonie@kernel.org, m.szyprowski@samsung.com Cc: christian@kohlschutter.com, heiko@sntech.de, lgirdwood@gmail.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mmc@vger.kernel.org, linux-rockchip@lists.infradead.org, m.reichl@fivetechno.de, robin.murphy@arm.com, vincent.legoll@gmail.com, wens@kernel.org Subject: [PATCH v5] regulator: core: Resolve supply name earlier to prevent double-init Date: Thu, 25 Aug 2022 21:28:42 +0000 Message-Id: <20220825212842.7176-1-christian@kohlschutter.com> X-Mailer: git-send-email 2.36.2 In-Reply-To: <932DEB17-70FB-4416-80B3-C48A7C31848F@kohlschutter.com> References: <932DEB17-70FB-4416-80B3-C48A7C31848F@kohlschutter.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mmc@vger.kernel.org Previously, an unresolved regulator supply reference upon calling regulator_register on an always-on or boot-on regulator caused set_machine_constraints to be called twice. This in turn may initialize the regulator twice, leading to voltage glitches that are timing-dependent. A simple, unrelated configuration change may be enough to hide this problem, only to be surfaced by chance. One such example is the SD-Card voltage regulator in a NanoPI R4S that would not initialize reliably unless the registration flow was just complex enough to allow the regulator to properly reset between calls. Fix this by re-arranging regulator_register, trying resolve the regulator's supply early enough that set_machine_constraints does not need to be called twice. Signed-off-by: Christian Kohlschütter Tested-by: Marek Szyprowski --- drivers/regulator/core.c | 58 ++++++++++++++++++++++++---------------- 1 file changed, 35 insertions(+), 23 deletions(-) diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index 77f60eef960..2ff0ab2730f 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -5391,6 +5391,7 @@ regulator_register(const struct regulator_desc *regulator_desc, bool dangling_of_gpiod = false; struct device *dev; int ret, i; + bool resolved_early = false; if (cfg == NULL) return ERR_PTR(-EINVAL); @@ -5494,24 +5495,10 @@ regulator_register(const struct regulator_desc *regulator_desc, BLOCKING_INIT_NOTIFIER_HEAD(&rdev->notifier); INIT_DELAYED_WORK(&rdev->disable_work, regulator_disable_work); - /* preform any regulator specific init */ - if (init_data && init_data->regulator_init) { - ret = init_data->regulator_init(rdev->reg_data); - if (ret < 0) - goto clean; - } - - if (config->ena_gpiod) { - ret = regulator_ena_gpio_request(rdev, config); - if (ret != 0) { - rdev_err(rdev, "Failed to request enable GPIO: %pe\n", - ERR_PTR(ret)); - goto clean; - } - /* The regulator core took over the GPIO descriptor */ - dangling_cfg_gpiod = false; - dangling_of_gpiod = false; - } + if (init_data && init_data->supply_regulator) + rdev->supply_name = init_data->supply_regulator; + else if (regulator_desc->supply_name) + rdev->supply_name = regulator_desc->supply_name; /* register with sysfs */ rdev->dev.class = ®ulator_class; @@ -5533,13 +5520,38 @@ regulator_register(const struct regulator_desc *regulator_desc, goto wash; } - if (init_data && init_data->supply_regulator) - rdev->supply_name = init_data->supply_regulator; - else if (regulator_desc->supply_name) - rdev->supply_name = regulator_desc->supply_name; + if ((rdev->supply_name && !rdev->supply) && + (rdev->constraints->always_on || + rdev->constraints->boot_on)) { + ret = regulator_resolve_supply(rdev); + if (ret != 0) + rdev_dbg(rdev, "Unable to resolve supply early: %pe\n", + ERR_PTR(ret)); + + resolved_early = true; + } + + /* perform any regulator specific init */ + if (init_data && init_data->regulator_init) { + ret = init_data->regulator_init(rdev->reg_data); + if (ret < 0) + goto wash; + } + + if (config->ena_gpiod) { + ret = regulator_ena_gpio_request(rdev, config); + if (ret != 0) { + rdev_err(rdev, "Failed to request enable GPIO: %pe\n", + ERR_PTR(ret)); + goto wash; + } + /* The regulator core took over the GPIO descriptor */ + dangling_cfg_gpiod = false; + dangling_of_gpiod = false; + } ret = set_machine_constraints(rdev); - if (ret == -EPROBE_DEFER) { + if (ret == -EPROBE_DEFER && !resolved_early) { /* Regulator might be in bypass mode and so needs its supply * to set the constraints */