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Date: Mon, 11 May 2020 22:25:41 -0700
From: Bjorn Andersson <bjorn.andersson@...aro.org>
To: Sumit Semwal <sumit.semwal@...aro.org>
Cc: agross@...nel.org, lgirdwood@...il.com, broonie@...nel.org,
robh+dt@...nel.org, nishakumari@...eaurora.org,
linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
devicetree@...r.kernel.org, kgunda@...eaurora.org,
rnayak@...eaurora.org
Subject: Re: [v2 4/4] regulator: qcom: labibb: Add SC interrupt handling
On Fri 08 May 13:42 PDT 2020, Sumit Semwal wrote:
> From: Nisha Kumari <nishakumari@...eaurora.org>
>
> Add Short circuit interrupt handling and recovery for the lab and
> ibb regulators on qcom platforms.
>
> The client panel drivers need to register for REGULATOR_EVENT_OVER_CURRENT
> notification which will be triggered on short circuit. They should
> try to enable the regulator once, and if it doesn't get enabled,
> handle shutting down the panel accordingly.
>
> Signed-off-by: Nisha Kumari <nishakumari@...eaurora.org>
> Signed-off-by: Sumit Semwal <sumit.semwal@...aro.org>
>
> --
> v2: sumits: reworked handling to user regmap_read_poll_timeout, and handle it
> per-regulator instead of clearing both lab and ibb errors on either irq
> triggering. Also added REGULATOR_EVENT_OVER_CURRENT handling and
> notification to clients.
> ---
> drivers/regulator/qcom-labibb-regulator.c | 103 +++++++++++++++++++++-
> 1 file changed, 100 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/regulator/qcom-labibb-regulator.c b/drivers/regulator/qcom-labibb-regulator.c
> index a9dc7c060375..3539631c9f96 100644
> --- a/drivers/regulator/qcom-labibb-regulator.c
> +++ b/drivers/regulator/qcom-labibb-regulator.c
> @@ -1,6 +1,7 @@
> // SPDX-License-Identifier: GPL-2.0
> // Copyright (c) 2019, The Linux Foundation. All rights reserved.
>
> +#include <linux/interrupt.h>
> #include <linux/module.h>
> #include <linux/of_irq.h>
> #include <linux/of.h>
> @@ -18,11 +19,15 @@
> #define REG_LABIBB_ENABLE_CTL 0x46
> #define LABIBB_STATUS1_VREG_OK_BIT BIT(7)
> #define LABIBB_CONTROL_ENABLE BIT(7)
> +#define LABIBB_STATUS1_SC_DETECT_BIT BIT(6)
>
> #define LAB_ENABLE_CTL_MASK BIT(7)
> #define IBB_ENABLE_CTL_MASK (BIT(7) | BIT(6))
>
> #define POWER_DELAY 8000
> +#define POLLING_SCP_DONE_INTERVAL_US 5000
> +#define POLLING_SCP_TIMEOUT 16000
> +
>
> struct labibb_regulator {
> struct regulator_desc desc;
> @@ -30,6 +35,8 @@ struct labibb_regulator {
> struct regmap *regmap;
> struct regulator_dev *rdev;
> u16 base;
> + int sc_irq;
> + int vreg_enabled;
> u8 type;
> };
>
> @@ -112,9 +119,10 @@ static int qcom_labibb_regulator_enable(struct regulator_dev *rdev)
> return ret;
> }
>
> - if (ret)
> + if (ret) {
> + reg->vreg_enabled = 1;
> return 0;
> -
> + }
>
> dev_err(reg->dev, "Can't enable %s\n", reg->desc.name);
> return -EINVAL;
> @@ -140,8 +148,10 @@ static int qcom_labibb_regulator_disable(struct regulator_dev *rdev)
> return ret;
> }
>
> - if (!ret)
> + if (!ret) {
> + reg->vreg_enabled = 0;
> return 0;
> + }
>
> dev_err(reg->dev, "Can't disable %s\n", reg->desc.name);
> return -EINVAL;
> @@ -153,6 +163,70 @@ static struct regulator_ops qcom_labibb_ops = {
> .is_enabled = qcom_labibb_regulator_is_enabled,
> };
>
> +
> +static irqreturn_t labibb_sc_err_handler(int irq, void *_reg)
> +{
> + int ret, count;
> + u16 reg;
> + u8 sc_err_mask;
> + unsigned int val;
> + struct labibb_regulator *labibb_reg = (struct labibb_regulator *)_reg;
No need to explicitly typecast a void *.
> + bool in_sc_err, reg_en, scp_done = false;
reg_en is unused.
> +
> + if (irq == labibb_reg->sc_irq)
When is this false?
> + reg = labibb_reg->base + REG_LABIBB_STATUS1;
> + else
> + return IRQ_HANDLED;
> +
> + sc_err_mask = LABIBB_STATUS1_SC_DETECT_BIT;
> +
> + ret = regmap_bulk_read(labibb_reg->regmap, reg, &val, 1);
Just inline reg->base + REG_LABIBB_STATUS1 in this call.
> + if (ret < 0) {
> + dev_err(labibb_reg->dev, "Read failed, ret=%d\n", ret);
> + return IRQ_HANDLED;
> + }
> + dev_dbg(labibb_reg->dev, "%s SC error triggered! STATUS1 = %d\n",
> + labibb_reg->desc.name, val);
> +
> + in_sc_err = !!(val & sc_err_mask);
> +
> + /*
> + * The SC(short circuit) fault would trigger PBS(Portable Batch
> + * System) to disable regulators for protection. This would
> + * cause the SC_DETECT status being cleared so that it's not
> + * able to get the SC fault status.
> + * Check if the regulator is enabled in the driver but
> + * disabled in hardware, this means a SC fault had happened
> + * and SCP handling is completed by PBS.
> + */
> + if (!in_sc_err) {
if (!(val & LABIBB_STATUS1_SC_DETECT_BIT)) {
> +
> + reg = labibb_reg->base + REG_LABIBB_ENABLE_CTL;
> +
> + ret = regmap_read_poll_timeout(labibb_reg->regmap,
> + reg, val,
> + !(val & LABIBB_CONTROL_ENABLE),
> + POLLING_SCP_DONE_INTERVAL_US,
> + POLLING_SCP_TIMEOUT);
> +
> + if (!ret && labibb_reg->vreg_enabled) {
Wouldn't be fine to assume that if you get a short circuit IRQ the
regulator is enabled?
If you are worried about racing with a disable this won't work anyways,
and you better enable_irq()/disable_irq() in regulator enable/disable,
respectively.
> + dev_dbg(labibb_reg->dev,
> + "%s has been disabled by SCP\n",
> + labibb_reg->desc.name);
> + scp_done = true;
> + }
If you flip the poll check around you will get here by not being in an
short-circuit condition and you conclude that the regulator is still on;
in which case you can just return here.
That way you can drop in_sc_err and scp_done and flatten below
conditional section.
> + }
> +
> + if (in_sc_err || scp_done) {
> + regulator_lock(labibb_reg->rdev);
> + regulator_notifier_call_chain(labibb_reg->rdev,
> + REGULATOR_EVENT_OVER_CURRENT,
> + NULL);
> + regulator_unlock(labibb_reg->rdev);
> + }
> + return IRQ_HANDLED;
> +}
> +
> static int register_labibb_regulator(struct qcom_labibb *labibb,
> const struct labibb_regulator_data *reg_data,
> struct device_node *of_node)
> @@ -181,6 +255,29 @@ static int register_labibb_regulator(struct qcom_labibb *labibb,
> reg->desc.type = REGULATOR_VOLTAGE;
> reg->desc.ops = &qcom_labibb_ops;
>
> + reg->sc_irq = -EINVAL;
> + ret = of_irq_get_byname(of_node, reg_data->irq_name);
> + if (ret < 0)
> + dev_dbg(labibb->dev,
Isn't this an error?
> + "Unable to get %s, ret = %d\n",
> + reg_data->irq_name, ret);
> + else
> + reg->sc_irq = ret;
> +
> + if (reg->sc_irq > 0) {
> + ret = devm_request_threaded_irq(labibb->dev,
> + reg->sc_irq,
> + NULL, labibb_sc_err_handler,
> + IRQF_ONESHOT |
> + IRQF_TRIGGER_RISING,
Omit IRQF_TRIGGER_RISING and let that come from DT.
> + reg_data->irq_name, labibb);
> + if (ret) {
> + dev_err(labibb->dev, "Failed to register '%s' irq ret=%d\n",
> + reg_data->irq_name, ret);
> + return ret;
> + }
> + }
> +
Regards,
Bjorn
> cfg.dev = labibb->dev;
> cfg.driver_data = reg;
> cfg.regmap = labibb->regmap;
> --
> 2.26.2
>
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