| Message ID | 20210109132921.140932-6-angelogioacchino.delregno@somainline.org |
|---|---|
| State | New |
| Headers | show |
| Series | Really implement Qualcomm LAB/IBB regulators | expand |
On Sat, Jan 09, 2021 at 02:29:19PM +0100, AngeloGioacchino Del Regno wrote: > + /* If the regulator is not enabled, this is a fake event */ > + if (!ops->is_enabled(vreg->rdev)) > + return 0; Or handling the interrupt raced with a disable initiated from elsewhere. Does the hardware actually have a problem with reporting spurious errors? > + return ret ? IRQ_NONE : IRQ_HANDLED; Here and elsewhere please write normal conditional statements to improve legibility. > + /* This function should be called only once, anyway. */ > + if (unlikely(vreg->ocp_irq_requested)) > + return 0; If this is not a fast path it doesn't need an unlikely() annotation; indeed it sounds more like there should be a warning printed if this isn't supposed to be called multiple times. > + /* IRQ polarities - LAB: trigger-low, IBB: trigger-high */ > + if (vreg->type == QCOM_LAB_TYPE) { > + irq_flags |= IRQF_TRIGGER_LOW; > + irq_trig_low = 1; > + } else { > + irq_flags |= IRQF_TRIGGER_HIGH; > + irq_trig_low = 0; > + } This would be more clearly written as a switch statement. > + return devm_request_threaded_irq(vreg->dev, vreg->ocp_irq, NULL, > + qcom_labibb_ocp_isr, irq_flags, > + ocp_irq_name, vreg); Are you *sure* that devm_ is appropriate here and the interrupt handler won't attempt to use things that will be deallocated before devm gets round to freeing the interrupt? > + if (!!(val & LABIBB_CONTROL_ENABLE)) { The !! is redundant here and makes things less clear. > @@ -166,8 +560,37 @@ static int qcom_labibb_of_parse_cb(struct device_node *np, > struct regulator_config *config) > { > struct labibb_regulator *vreg = config->driver_data; > + char *sc_irq_name; I really, really wouldn't expect to see interrupts being requested in the DT parsing callback - apart from anything else the device is going to have the physical interrupts with or without DT binding information. These callbacks are for regulator specific properties, not basic probing. Just request the interrupts in the main probe function, this also means you can avoid using all the DT specific APIs which are generally a warning sign.
Il 11/01/21 14:57, Mark Brown ha scritto: > On Sat, Jan 09, 2021 at 02:29:19PM +0100, AngeloGioacchino Del Regno wrote: > >> + /* If the regulator is not enabled, this is a fake event */ >> + if (!ops->is_enabled(vreg->rdev)) >> + return 0; > > Or handling the interrupt raced with a disable initiated from elsewhere. > Does the hardware actually have a problem with reporting spurious errors? > >> + return ret ? IRQ_NONE : IRQ_HANDLED; > > Here and elsewhere please write normal conditional statements to improve > legibility. > No problem. Will do. >> + /* This function should be called only once, anyway. */ >> + if (unlikely(vreg->ocp_irq_requested)) >> + return 0; > > If this is not a fast path it doesn't need an unlikely() annotation; > indeed it sounds more like there should be a warning printed if this > isn't supposed to be called multiple times. > That was extra-paranoid safety, looking at this one again, that should be totally unnecessary. I think that removing this check entirely would be just fine also because.. anyway.. writing to these registers more than once won't do any harm, nor break functionality: I mean, even if it happens for whatever reason, there's *no real need* to avoid it from the hw perspective. >> + /* IRQ polarities - LAB: trigger-low, IBB: trigger-high */ >> + if (vreg->type == QCOM_LAB_TYPE) { >> + irq_flags |= IRQF_TRIGGER_LOW; >> + irq_trig_low = 1; >> + } else { >> + irq_flags |= IRQF_TRIGGER_HIGH; >> + irq_trig_low = 0; >> + } > > This would be more clearly written as a switch statement. > A switch statement looked like being a bit "too much" for just two cases where vreg->type cannot be anything else but QCOM_LAB_TYPE or QCOM_IBB_TYPE... but okay, let's write a switch statement in place of that. >> + return devm_request_threaded_irq(vreg->dev, vreg->ocp_irq, NULL, >> + qcom_labibb_ocp_isr, irq_flags, >> + ocp_irq_name, vreg); > > Are you *sure* that devm_ is appropriate here and the interrupt handler > won't attempt to use things that will be deallocated before devm gets > round to freeing the interrupt? > Yeah, I'm definitely sure. >> + if (!!(val & LABIBB_CONTROL_ENABLE)) { > > The !! is redundant here and makes things less clear. > My bad, I forgot to clean this one up before sending. >> @@ -166,8 +560,37 @@ static int qcom_labibb_of_parse_cb(struct device_node *np, >> struct regulator_config *config) >> { >> struct labibb_regulator *vreg = config->driver_data; >> + char *sc_irq_name; > > I really, really wouldn't expect to see interrupts being requested in > the DT parsing callback - apart from anything else the device is going > to have the physical interrupts with or without DT binding information. > These callbacks are for regulator specific properties, not basic probing. > Just request the interrupts in the main probe function, this also means > you can avoid using all the DT specific APIs which are generally a > warning sign. > ...And I even wrote a comment saying "The Short Circuit interrupt is critical: fail if not found"!!! Whoa! That was bad. Yeah, I'm definitely moving that to the appropriate place.
Il 11/01/21 20:23, AngeloGioacchino Del Regno ha scritto: > Il 11/01/21 20:14, AngeloGioacchino Del Regno ha scritto: >> Il 11/01/21 14:57, Mark Brown ha scritto: >>> On Sat, Jan 09, 2021 at 02:29:19PM +0100, AngeloGioacchino Del Regno >>> wrote: >>> >>>> + /* If the regulator is not enabled, this is a fake event */ >>>> + if (!ops->is_enabled(vreg->rdev)) >>>> + return 0; >>> >>> Or handling the interrupt raced with a disable initiated from elsewhere. >>> Does the hardware actually have a problem with reporting spurious >>> errors? >>> > Sorry, I forgot to answer to this one in the previous email. > > Yes, apparently the hardware has this issue: when the current draw is > very high and you disable the regulator while the attached device is > still drawing a lot of current (like on the Xperia XZ2 smartphone, but I > don't want to comment on that phone's HW quirks...) then the OCP > interrupt fires *after* disabling the LAB/IBB regulators. > > This doesn't seem to happen if the current draw is low in the exact > moment the regulator gets disabled, but that's not always possible since > it depends on external HW design / board design sometimes... > > >>>> + return ret ? IRQ_NONE : IRQ_HANDLED; >>> >>> Here and elsewhere please write normal conditional statements to improve >>> legibility. >>> >> No problem. Will do. >> >>>> + /* This function should be called only once, anyway. */ >>>> + if (unlikely(vreg->ocp_irq_requested)) >>>> + return 0; >>> >>> If this is not a fast path it doesn't need an unlikely() annotation; >>> indeed it sounds more like there should be a warning printed if this >>> isn't supposed to be called multiple times. >>> >> That was extra-paranoid safety, looking at this one again, that should >> be totally unnecessary. >> I think that removing this check entirely would be just fine also >> because.. anyway.. writing to these registers more than once won't do >> any harm, nor break functionality: I mean, even if it happens for >> whatever reason, there's *no real need* to avoid it from the hw >> perspective. >> >>>> + /* IRQ polarities - LAB: trigger-low, IBB: trigger-high */ >>>> + if (vreg->type == QCOM_LAB_TYPE) { >>>> + irq_flags |= IRQF_TRIGGER_LOW; >>>> + irq_trig_low = 1; >>>> + } else { >>>> + irq_flags |= IRQF_TRIGGER_HIGH; >>>> + irq_trig_low = 0; >>>> + } >>> >>> This would be more clearly written as a switch statement. >>> >> A switch statement looked like being a bit "too much" for just two >> cases where vreg->type cannot be anything else but QCOM_LAB_TYPE or >> QCOM_IBB_TYPE... but okay, let's write a switch statement in place of >> that. >> >>>> + return devm_request_threaded_irq(vreg->dev, vreg->ocp_irq, NULL, >>>> + qcom_labibb_ocp_isr, irq_flags, >>>> + ocp_irq_name, vreg); >>> >>> Are you *sure* that devm_ is appropriate here and the interrupt handler >>> won't attempt to use things that will be deallocated before devm gets >>> round to freeing the interrupt? >>> >> Yeah, I'm definitely sure. >> >>>> + if (!!(val & LABIBB_CONTROL_ENABLE)) { >>> >>> The !! is redundant here and makes things less clear. >>> >> My bad, I forgot to clean this one up before sending. >> >>>> @@ -166,8 +560,37 @@ static int qcom_labibb_of_parse_cb(struct >>>> device_node *np, >>>> struct regulator_config *config) >>>> { >>>> struct labibb_regulator *vreg = config->driver_data; >>>> + char *sc_irq_name; >>> >>> I really, really wouldn't expect to see interrupts being requested in >>> the DT parsing callback - apart from anything else the device is going >>> to have the physical interrupts with or without DT binding information. >>> These callbacks are for regulator specific properties, not basic >>> probing. >>> Just request the interrupts in the main probe function, this also means >>> you can avoid using all the DT specific APIs which are generally a >>> warning sign. >>> >> >> ...And I even wrote a comment saying "The Short Circuit interrupt is >> critical: fail if not found"!!! Whoa! That was bad. >> Yeah, I'm definitely moving that to the appropriate place. > I'm sorry for the triple e-mail... but I've just acknowledged that using platform_get_irq is actually impossible with the current schema. As you can see in the dt-bindings documentation, the driver is supposed to be declared in DT as labibb { compatible = "qcom,pmi8998-lab-ibb"; ibb: ibb { interrupts = <0x3 0xdc 0x2 IRQ_TYPE_EDGE_RISING>, <0x3 0xdc 0x0 IRQ_TYPE_LEVEL_HIGH>; interrupt-names = "sc-err", "ocp"; }; lab: lab { interrupts = <0x3 0xde 0x1 IRQ_TYPE_EDGE_RISING>, <0x3 0xde 0x0 IRQ_TYPE_LEVEL_LOW>; interrupt-names = "sc-err", "ocp"; }; }; ...which was already a requirement before I touched it. Now, this leaves two options here: 1. Keep the of_get_irq way, or 2. Move the interrupts, change the documentation (currently, only pmi8998.dtsi) and also fix pmi8998.dtsi to reflect the new changes. I am asking before proceeding because I know that changing a schema that is already set sometimes gets "negated". How should I proceed? -- Angelo
On Mon, Jan 11, 2021 at 10:06:18PM +0100, AngeloGioacchino Del Regno wrote: > ...which was already a requirement before I touched it. > Now, this leaves two options here: > 1. Keep the of_get_irq way, or > 2. Move the interrupts, change the documentation (currently, only > pmi8998.dtsi) and also fix pmi8998.dtsi to reflect the new changes. > I am asking before proceeding because I know that changing a schema that is > already set sometimes gets "negated". Well, if the binding isn't actually used changing it is a possibility. If we keep the current binding you can still continue to use of_get_irq() even from within the probe function, you know the name of the node it's supposed to be in so you don't need to iterate or anything to get it so not really any reason to use the callback.
Il 12/01/21 18:29, Mark Brown ha scritto: > On Mon, Jan 11, 2021 at 10:06:18PM +0100, AngeloGioacchino Del Regno wrote: > >> ...which was already a requirement before I touched it. >> Now, this leaves two options here: >> 1. Keep the of_get_irq way, or >> 2. Move the interrupts, change the documentation (currently, only >> pmi8998.dtsi) and also fix pmi8998.dtsi to reflect the new changes. > >> I am asking before proceeding because I know that changing a schema that is >> already set sometimes gets "negated". > > Well, if the binding isn't actually used changing it is a possibility. > If we keep the current binding you can still continue to use > of_get_irq() even from within the probe function, you know the name of > the node it's supposed to be in so you don't need to iterate or anything > to get it so not really any reason to use the callback. > I had understood that you didn't want to see of_* functions used in the driver, that's why I was hesitant about the first one. I would be more for keeping the binding (that, by the way, is not really used, the interrupts weren't implemented at all in the driver before me doing that) for just one reason, which I'm going to explain with "sort of" pseudocode (just to be shorter): EXAMPLE 1: labibb { interrupts = <0 0>, <1 0>, <2 0>, <3 0>; interrupt-names = "lab-sc", "lab-ocp", "ibb-sc", "ibb-ocp"; lab { }; ibb { }; }; for (i = 0; i < max_vregs; i++) { short_circuit = platform_get_irq(pdev, i * 2); overcurrent = platform_get_irq(pdev, ((i * 2) + 1)); } EXAMPLE 2: snprintf strings for {lab,ibb}_{shortcircuit,overcurrent}, use platform_get_irq_byname (pdev, blah); EXAMPLE 3: labibb { lab { interrupts = <0 0>, <1 0>; interrupt-names = "sc", "ocp"; }; ibb { interrupts = <2 0>, <3 0>; interrupt-names = "sc", "ocp"; }; }; for (i = 0; i < max_vregs; i++) { short_circuit = of_irq_get_byname(node, "sc"); overcurrent = of_irq_get_byname(node, "ocp"); } First of all, in the *EXAMPLE 1*, we may be declaring interrupts for both LAB and IBB, but actually disabling one of the two regulators: in this specific case (I have no idea why anyone would want to do that, but evaluating all the cases anyway) the human readability would be way lower, in my opinion, as that'd add a possible layer of confusion. Also, I don't really like having to preallocate an array of chars and snprintf names here and there (EXAMPLE 2) on the fly: in my eyes, it looks a bit of a mess, but that's a highly personal opinion, many may disagree. In *EXAMPLE 3* everything looks more human readable and, in some way, less error-prone, as we can just use two fixed strings and that's it, without multiplying this and adding that. I would go for keeping the current binding for the aforementioned reasons. Before I go on sending a V2, I would like to know your opinion. Do you agree? Thanks, -- Angelo
On Tue, Jan 12, 2021 at 06:49:53PM +0100, AngeloGioacchino Del Regno wrote: > I would go for keeping the current binding for the aforementioned reasons. > Before I go on sending a V2, I would like to know your opinion. > Do you agree? Sure.
diff --git a/drivers/regulator/qcom-labibb-regulator.c b/drivers/regulator/qcom-labibb-regulator.c index 21175e297c1f..413506481a08 100644 --- a/drivers/regulator/qcom-labibb-regulator.c +++ b/drivers/regulator/qcom-labibb-regulator.c @@ -17,8 +17,20 @@ #define PMI8998_LAB_REG_BASE 0xde00 #define PMI8998_IBB_REG_BASE 0xdc00 +#define PMI8998_IBB_LAB_REG_OFFSET 0x200 #define REG_LABIBB_STATUS1 0x08 + #define LABIBB_STATUS1_SC_BIT BIT(6) + #define LABIBB_STATUS1_VREG_OK_BIT BIT(7) + +#define REG_LABIBB_INT_SET_TYPE 0x11 +#define REG_LABIBB_INT_POLARITY_HIGH 0x12 +#define REG_LABIBB_INT_POLARITY_LOW 0x13 +#define REG_LABIBB_INT_LATCHED_CLR 0x14 +#define REG_LABIBB_INT_EN_SET 0x15 +#define REG_LABIBB_INT_EN_CLR 0x16 + #define LABIBB_INT_VREG_OK BIT(0) + #define LABIBB_INT_VREG_TYPE_LEVEL 0 #define REG_LABIBB_VOLTAGE 0x41 #define LABIBB_VOLTAGE_OVERRIDE_EN BIT(7) @@ -26,8 +38,7 @@ #define IBB_VOLTAGE_SET_MASK GENMASK(5, 0) #define REG_LABIBB_ENABLE_CTL 0x46 -#define LABIBB_STATUS1_VREG_OK_BIT BIT(7) -#define LABIBB_CONTROL_ENABLE BIT(7) + #define LABIBB_CONTROL_ENABLE BIT(7) #define REG_LABIBB_PD_CTL 0x47 #define LAB_PD_CTL_MASK GENMASK(1, 0) @@ -56,6 +67,11 @@ #define LAB_ENABLE_TIME (LABIBB_OFF_ON_DELAY * 2) #define IBB_ENABLE_TIME (LABIBB_OFF_ON_DELAY * 10) #define LABIBB_POLL_ENABLED_TIME 1000 +#define OCP_RECOVERY_INTERVAL_MS 500 +#define SC_RECOVERY_INTERVAL_MS 250 +#define LABIBB_MAX_OCP_COUNT 4 +#define LABIBB_MAX_SC_COUNT 3 +#define LABIBB_MAX_FATAL_COUNT 2 struct labibb_current_limits { u32 uA_min; @@ -69,10 +85,18 @@ struct labibb_regulator { struct regmap *regmap; struct regulator_dev *rdev; struct labibb_current_limits uA_limits; + struct delayed_work ocp_recovery_work; + struct delayed_work sc_recovery_work; u16 base; u8 type; u8 dischg_sel; u8 soft_start_sel; + int sc_irq; + int sc_count; + int ocp_irq; + int ocp_irq_count; + int fatal_count; + bool ocp_irq_requested; }; struct labibb_regulator_data { @@ -82,6 +106,376 @@ struct labibb_regulator_data { const struct regulator_desc *desc; }; +static int qcom_labibb_ocp_hw_enable(struct regulator_dev *rdev) +{ + struct labibb_regulator *vreg = rdev_get_drvdata(rdev); + int ret; + + /* Clear irq latch status to avoid spurious event */ + ret = regmap_update_bits(rdev->regmap, + vreg->base + REG_LABIBB_INT_LATCHED_CLR, + LABIBB_INT_VREG_OK, 1); + if (ret) + return ret; + + /* Enable OCP HW interrupt */ + return regmap_update_bits(rdev->regmap, + vreg->base + REG_LABIBB_INT_EN_SET, + LABIBB_INT_VREG_OK, 1); +} + +static int qcom_labibb_ocp_hw_disable(struct regulator_dev *rdev) +{ + struct labibb_regulator *vreg = rdev_get_drvdata(rdev); + + return regmap_update_bits(rdev->regmap, + vreg->base + REG_LABIBB_INT_EN_CLR, + LABIBB_INT_VREG_OK, 1); +} + +/* + * qcom_labibb_check_ocp_status - Check the Over-Current Protection status + * @rdev: Regulator device + * + * This function checks the STATUS1 register for the VREG_OK bit: if it is + * set, then there is no Over-Current event. + * + * Returns: Zero if there is no over-current, 1 if in over-current or + * negative number for error + */ +static int qcom_labibb_check_ocp_status(struct labibb_regulator *vreg) +{ + u32 cur_status; + int ret; + + ret = regmap_read(vreg->rdev->regmap, vreg->base + REG_LABIBB_STATUS1, + &cur_status); + if (ret) + return ret; + + return !(cur_status & LABIBB_STATUS1_VREG_OK_BIT); +} + +static void qcom_labibb_ocp_recovery_worker(struct work_struct *work) +{ + struct labibb_regulator *vreg; + const struct regulator_ops *ops; + int ret; + + vreg = container_of(work, struct labibb_regulator, + ocp_recovery_work.work); + ops = vreg->rdev->desc->ops; + + if (vreg->ocp_irq_count >= LABIBB_MAX_OCP_COUNT) { + /* + * If we tried to disable the regulator multiple times but + * we kept failing, there's only one last hope to save our + * hardware from the death: raise a kernel bug, reboot and + * hope that the bootloader kindly saves us. This, though + * is done only as paranoid checking, because failing the + * regmap write to disable the vreg is almost impossible, + * since we got here after multiple regmap R/W. + */ + BUG_ON(vreg->fatal_count > LABIBB_MAX_FATAL_COUNT); + dev_err(&vreg->rdev->dev, "LABIBB: CRITICAL: Disabling regulator\n"); + + /* Disable the regulator immediately to avoid damage */ + ret = ops->disable(vreg->rdev); + if (ret) { + vreg->fatal_count++; + goto reschedule; + } + enable_irq(vreg->ocp_irq); + vreg->fatal_count = 0; + return; + } + + ret = qcom_labibb_check_ocp_status(vreg); + if (ret != 0) { + vreg->ocp_irq_count++; + goto reschedule; + } + + ret = qcom_labibb_ocp_hw_enable(vreg->rdev); + if (ret) { + /* We cannot trust it without OCP enabled. */ + dev_err(vreg->dev, "Cannot enable OCP IRQ\n"); + vreg->ocp_irq_count++; + goto reschedule; + } + + enable_irq(vreg->ocp_irq); + /* Everything went fine: reset the OCP count! */ + vreg->ocp_irq_count = 0; + return; + +reschedule: + mod_delayed_work(system_wq, &vreg->ocp_recovery_work, + msecs_to_jiffies(OCP_RECOVERY_INTERVAL_MS)); +} + +static irqreturn_t qcom_labibb_ocp_isr(int irq, void *chip) +{ + struct labibb_regulator *vreg = chip; + const struct regulator_ops *ops = vreg->rdev->desc->ops; + int ret; + + /* If the regulator is not enabled, this is a fake event */ + if (!ops->is_enabled(vreg->rdev)) + return 0; + + /* If we tried to recover for too many times it's not getting better */ + if (vreg->ocp_irq_count > LABIBB_MAX_OCP_COUNT) + return IRQ_NONE; + + /* + * If we (unlikely) can't read this register, to prevent hardware + * damage at all costs, we assume that the overcurrent event was + * real; Moreover, if the status register is not signaling OCP, + * it was a spurious event, so it's all ok. + */ + ret = qcom_labibb_check_ocp_status(vreg); + if (ret == 0) { + vreg->ocp_irq_count = 0; + goto end; + } + vreg->ocp_irq_count++; + + /* + * Disable the interrupt temporarily, or it will fire continuously; + * we will re-enable it in the recovery worker function. + */ + disable_irq(irq); + + /* Warn the user for overcurrent */ + dev_warn(vreg->dev, "Over-Current interrupt fired!\n"); + + /* Disable the interrupt to avoid hogging */ + ret = qcom_labibb_ocp_hw_disable(vreg->rdev); + if (ret) + goto end; + + /* Signal overcurrent event to drivers */ + regulator_notifier_call_chain(vreg->rdev, + REGULATOR_EVENT_OVER_CURRENT, NULL); + +end: + /* Schedule the recovery work */ + schedule_delayed_work(&vreg->ocp_recovery_work, + msecs_to_jiffies(OCP_RECOVERY_INTERVAL_MS)); + return ret ? IRQ_NONE : IRQ_HANDLED; +} + +static int qcom_labibb_set_ocp(struct regulator_dev *rdev) +{ + struct labibb_regulator *vreg = rdev_get_drvdata(rdev); + char *ocp_irq_name; + u32 irq_flags = IRQF_ONESHOT; + int irq_trig_low, ret; + + /* If there is no OCP interrupt, there's nothing to set */ + if (vreg->ocp_irq <= 0) + return -EINVAL; + + /* This function should be called only once, anyway. */ + if (unlikely(vreg->ocp_irq_requested)) + return 0; + vreg->ocp_irq_requested = true; + + ocp_irq_name = devm_kasprintf(vreg->dev, GFP_KERNEL, "%s-over-current", + vreg->desc.name); + if (!ocp_irq_name) + return -ENOMEM; + + /* IRQ polarities - LAB: trigger-low, IBB: trigger-high */ + if (vreg->type == QCOM_LAB_TYPE) { + irq_flags |= IRQF_TRIGGER_LOW; + irq_trig_low = 1; + } else { + irq_flags |= IRQF_TRIGGER_HIGH; + irq_trig_low = 0; + } + + /* Activate OCP HW level interrupt */ + ret = regmap_update_bits(rdev->regmap, + vreg->base + REG_LABIBB_INT_SET_TYPE, + LABIBB_INT_VREG_OK, + LABIBB_INT_VREG_TYPE_LEVEL); + if (ret) + return ret; + + /* Set OCP interrupt polarity */ + ret = regmap_update_bits(rdev->regmap, + vreg->base + REG_LABIBB_INT_POLARITY_HIGH, + LABIBB_INT_VREG_OK, !irq_trig_low); + if (ret) + return ret; + ret = regmap_update_bits(rdev->regmap, + vreg->base + REG_LABIBB_INT_POLARITY_LOW, + LABIBB_INT_VREG_OK, irq_trig_low); + if (ret) + return ret; + + ret = qcom_labibb_ocp_hw_enable(rdev); + if (ret) + return ret; + + return devm_request_threaded_irq(vreg->dev, vreg->ocp_irq, NULL, + qcom_labibb_ocp_isr, irq_flags, + ocp_irq_name, vreg); +} + +/* + * qcom_labibb_check_sc_status - Check the Short Circuit Protection status + * @rdev: Regulator device + * + * This function checks the STATUS1 register on both LAB and IBB regulators + * for the ShortCircuit bit: if it is set on *any* of them, then we have + * experienced a short-circuit event. + * + * Returns: Zero if there is no short-circuit, 1 if in short-circuit or + * negative number for error + */ +static int qcom_labibb_check_sc_status(struct labibb_regulator *vreg) +{ + u32 ibb_status, ibb_reg, lab_status, lab_reg; + int ret; + + /* We have to work on both regulators due to PBS... */ + lab_reg = ibb_reg = vreg->base; + if (vreg->type == QCOM_LAB_TYPE) + ibb_reg -= PMI8998_IBB_LAB_REG_OFFSET; + else + lab_reg += PMI8998_IBB_LAB_REG_OFFSET; + + ret = regmap_read(vreg->rdev->regmap, lab_reg, &lab_status); + if (ret) + return ret; + ret = regmap_read(vreg->rdev->regmap, ibb_reg, &ibb_status); + if (ret) + return ret; + + return !!(lab_status & LABIBB_STATUS1_SC_BIT) || + !!(ibb_status & LABIBB_STATUS1_SC_BIT); +} + +static void qcom_labibb_sc_recovery_worker(struct work_struct *work) +{ + struct labibb_regulator *vreg; + const struct regulator_ops *ops; + u32 lab_reg, ibb_reg, temp, val; + bool pbs_cut = false; + int i, sc, ret; + + vreg = container_of(work, struct labibb_regulator, + sc_recovery_work.work); + ops = vreg->rdev->desc->ops; + + /* + * If we tried to check the regulator status multiple times but we + * kept failing, then just bail out, as the Portable Batch System + * (PBS) will disable the vregs for us, preventing hardware damage. + */ + if (vreg->fatal_count > LABIBB_MAX_FATAL_COUNT) + return; + + /* Too many short-circuit events. Throw in the towel. */ + if (vreg->sc_count > LABIBB_MAX_SC_COUNT) + return; + + /* + * The Portable Batch System (PBS) automatically disables LAB + * and IBB when a short-circuit event is detected, so we have to + * check and work on both of them at the same time. + */ + lab_reg = ibb_reg = vreg->base; + if (vreg->type == QCOM_LAB_TYPE) + ibb_reg -= PMI8998_IBB_LAB_REG_OFFSET; + else + lab_reg += PMI8998_IBB_LAB_REG_OFFSET; + + sc = qcom_labibb_check_sc_status(vreg); + if (sc) + goto reschedule; + + for (i = 0; i < LABIBB_MAX_SC_COUNT; i++) { + ret = regmap_read(vreg->regmap, lab_reg, &temp); + if (ret) { + vreg->fatal_count++; + goto reschedule; + } + val = temp; + + ret = regmap_read(vreg->regmap, ibb_reg, &temp); + if (ret) { + vreg->fatal_count++; + goto reschedule; + } + val &= temp; + + if (!!(val & LABIBB_CONTROL_ENABLE)) { + usleep_range(5000, 6000); + continue; + } + pbs_cut = true; + break; + } + if (pbs_cut) + goto reschedule; + + /* + * If we have reached this point, we either had a spurious SC IRQ + * or we have successfully recovered from the SC condition, which + * means that we can re-enable the regulators, if they have ever + * been disabled by the PBS. + */ + ret = ops->enable(vreg->rdev); + if (ret) + goto reschedule; + + /* Everything went fine: reset the OCP count! */ + vreg->sc_count = 0; + enable_irq(vreg->sc_irq); + return; + +reschedule: + /* + * Now that we have done basic handling of the short-circuit, + * reschedule this worker in the regular system workqueue, as + * taking action is not truly urgent anymore. + */ + vreg->sc_count++; + mod_delayed_work(system_wq, &vreg->sc_recovery_work, + msecs_to_jiffies(SC_RECOVERY_INTERVAL_MS)); +} + +static irqreturn_t qcom_labibb_sc_isr(int irq, void *chip) +{ + struct labibb_regulator *vreg = chip; + + if (vreg->sc_count > LABIBB_MAX_SC_COUNT) + return IRQ_NONE; + + /* Warn the user for short circuit */ + dev_warn(vreg->dev, "Short-Circuit interrupt fired!\n"); + + /* + * Disable the interrupt temporarily, or it will fire continuously; + * we will re-enable it in the recovery worker function. + */ + disable_irq(irq); + + /* Signal out of regulation event to drivers */ + regulator_notifier_call_chain(vreg->rdev, + REGULATOR_EVENT_REGULATION_OUT, NULL); + + /* Schedule the short-circuit handling as high-priority work */ + mod_delayed_work(system_highpri_wq, &vreg->sc_recovery_work, + msecs_to_jiffies(SC_RECOVERY_INTERVAL_MS)); + return IRQ_HANDLED; +} + + static int qcom_labibb_set_current_limit(struct regulator_dev *rdev, int min_uA, int max_uA) { @@ -166,8 +560,37 @@ static int qcom_labibb_of_parse_cb(struct device_node *np, struct regulator_config *config) { struct labibb_regulator *vreg = config->driver_data; + char *sc_irq_name; u32 dischg_kohms, soft_start_time; - int ret; + int irq, ret; + + /* The Short Circuit interrupt is critical: fail if not found */ + irq = of_irq_get(np, 0); + if (irq <= 0) + return dev_err_probe(vreg->dev, (irq == 0 ? -EINVAL : irq), + "Short-circuit interrupt not found.\n"); + vreg->sc_irq = irq; + INIT_DELAYED_WORK(&vreg->sc_recovery_work, + qcom_labibb_sc_recovery_worker); + + sc_irq_name = devm_kasprintf(vreg->dev, GFP_KERNEL, "%s-short-circuit", + vreg->desc.name); + if (!sc_irq_name) + return -ENOMEM; + + ret = devm_request_threaded_irq(vreg->dev, vreg->sc_irq, NULL, + qcom_labibb_sc_isr, + IRQF_ONESHOT | IRQF_TRIGGER_RISING, + sc_irq_name, vreg); + if (ret) + return ret; + + /* OverCurrent Protection IRQ is optional */ + irq = of_irq_get(np, 1); + vreg->ocp_irq = irq; + vreg->ocp_irq_count = 0; + INIT_DELAYED_WORK(&vreg->ocp_recovery_work, + qcom_labibb_ocp_recovery_worker); ret = of_property_read_u32(np, "qcom,discharge-resistor-kohms", &dischg_kohms); @@ -209,6 +632,7 @@ static const struct regulator_ops qcom_labibb_ops = { .set_current_limit = qcom_labibb_set_current_limit, .get_current_limit = qcom_labibb_get_current_limit, .set_soft_start = qcom_labibb_set_soft_start, + .set_over_current_protection = qcom_labibb_set_ocp, }; static const struct regulator_desc pmi8998_lab_desc = {
Short-Circuit Protection (SCP) and Over-Current Protection (OCP) are very important for regulators like LAB and IBB, which are designed to provide from very small to relatively big amounts of current to the device (normally, a display). Now that this regulator supports both voltage setting and current limiting in this driver, to me it looked like being somehow essential to provide support for SCP and OCP, for two reasons: 1. SCP is a drastic measure to prevent damaging "more" hardware in the worst situations, if any was damaged, preventing potentially drastic issues; 2. OCP is a great way to protect the hardware that we're powering through these regulators as if anything bad happens, the HW will draw more current than expected: in this case, the OCP interrupt will fire and the regulators will be immediately shut down, preventing hardware damage in many cases. Both interrupts were successfully tested in a "sort-of" controlled manner, with the following methodology: Short-Circuit Protection (SCP): 1. Set LAB/IBB to 4.6/-1.4V, current limit 200mA/50mA; 2. Connect a 10 KOhm resistor to LAB/IBB by poking the right traces on a FxTec Pro1 smartphone for a very brief time (in short words, "just a rapid touch with flying wires"); 3. The Short-Circuit protection trips: IRQ raises, regulators get cut. Recovery OK, test repeated without rebooting, OK. Over-Current Protection (OCP): 1. Set LAB/IBB to the expected voltage to power up the display of a Sony Xperia XZ Premium smartphone (Sharp LS055D1SX04), set current limit to LAB 200mA, IBB 50mA (the values that this display unit needs are 200/800mA); 2. Boot the kernel: OCP fires. Recovery never happens because the selected current limit is too low, but that's expected. Test OK. 3. Set LAB/IBB to the expected current limits for XZ Premium (LAB 200mA, IBB 800mA), but lower than expected voltage, specifically LAB 5.4V, IBB -5.6V (instead of 5.6, -5.8V); 4. Boot the kernel: OCP fires. Recovery never happens because the selected voltage (still in the working range limits) is producing a current draw of more than 200mA on LAB. Test OK. Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org> --- drivers/regulator/qcom-labibb-regulator.c | 430 +++++++++++++++++++++- 1 file changed, 427 insertions(+), 3 deletions(-)