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Date:   Thu, 28 May 2020 19:28:47 -0700
From:   Bjorn Andersson <bjorn.andersson@linaro.org>
To:     Sumit Semwal <sumit.semwal@linaro.org>
Cc:     agross@kernel.org, lgirdwood@gmail.com, broonie@kernel.org,
        robh+dt@kernel.org, nishakumari@codeaurora.org,
        linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
        devicetree@vger.kernel.org, kgunda@codeaurora.org,
        rnayak@codeaurora.org
Subject: Re: [PATCH v3 5/5] regulator: qcom: labibb: Add SC interrupt handling
Message-ID: <20200529022847.GO279327@builder.lan>
References: <20200528154625.17742-1-sumit.semwal@linaro.org>
 <20200528154625.17742-6-sumit.semwal@linaro.org>
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In-Reply-To: <20200528154625.17742-6-sumit.semwal@linaro.org>
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On Thu 28 May 08:46 PDT 2020, Sumit Semwal wrote:

> From: Nisha Kumari <nishakumari@codeaurora.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@codeaurora.org>

It would be nice to see a short summary of your changes from the
original patch here, like:

[sumit: Changed this and that]

> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.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.
> v3: sumits: updated as per review comments of v2: removed spurious check for
>      irq in handler and some unused variables; inlined some of the code,
>      omitted IRQF_TRIGGER_RISING as it's coming from DT.
> 
> ---
>  drivers/regulator/qcom-labibb-regulator.c | 92 +++++++++++++++++++++++
>  1 file changed, 92 insertions(+)
> 
> diff --git a/drivers/regulator/qcom-labibb-regulator.c b/drivers/regulator/qcom-labibb-regulator.c
> index 634d08461c6e..695ffac71e81 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-only
>  // Copyright (c) 2020, The Linux Foundation. All rights reserved.
>  
> +#include <linux/interrupt.h>
>  #include <linux/module.h>
>  #include <linux/of_irq.h>
>  #include <linux/of.h>
> @@ -18,6 +19,7 @@
>  #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))
> @@ -27,12 +29,17 @@
>  #define IBB_POLL_ENABLED_TIME		(LABIBB_ENABLE_TIME * 10)
>  #define LABIBB_OFF_ON_DELAY		(8200)
>  
> +#define POLLING_SCP_DONE_INTERVAL_US	5000
> +#define POLLING_SCP_TIMEOUT		16000
> +
>  struct labibb_regulator {
>  	struct regulator_desc		desc;
>  	struct device			*dev;
>  	struct regmap			*regmap;
>  	struct regulator_dev		*rdev;
>  	u16				base;
> +	int				sc_irq;

This is now a local variable in register_labibb_regulator().

> +	int				vreg_enabled;

bool is a better representation of this (and the vreg_ prefix doesn't
really add value).

>  	u8				type;
>  };
>  
> @@ -65,6 +72,8 @@ static int qcom_labibb_regulator_enable(struct regulator_dev *rdev)
>  	if (ret < 0)
>  		dev_err(reg->dev, "Write failed: enable %s regulator\n",
>  			reg->desc.name);
> +	else
> +		reg->vreg_enabled = 1;

No I see why you add these wrappers around the regmap in the previous
patch.

My request to not print an error message on enable/disable errors
remains.

>  
>  	return ret;
>  }
> @@ -78,6 +87,8 @@ static int qcom_labibb_regulator_disable(struct regulator_dev *rdev)
>  	if (ret < 0)
>  		dev_err(reg->dev, "Disable failed: disable %s\n",
>  			reg->desc.name);
> +	else
> +		reg->vreg_enabled = 0;
>  
>  	return ret;
>  }
> @@ -88,11 +99,70 @@ 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;
> +	u16 reg;
> +	unsigned int val;
> +	struct labibb_regulator *labibb_reg = _reg;
> +	bool in_sc_err, scp_done = false;
> +
> +	ret = regmap_read(labibb_reg->regmap,
> +			  labibb_reg->base + REG_LABIBB_STATUS1, &val);
> +	if (ret < 0) {
> +		dev_err(labibb_reg->dev, "sc_err_irq: 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 & LABIBB_STATUS1_SC_DETECT_BIT);
> +
> +	/*
> +	 * 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) {
> +

Empty line

Regards,
Bjorn

> +		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) {
> +			dev_dbg(labibb_reg->dev,
> +				"%s has been disabled by SCP\n",
> +				labibb_reg->desc.name);
> +			scp_done = true;
> +		}
> +	}
> +
> +	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 labibb_regulator *reg,
>  				const struct labibb_regulator_data *reg_data,
>  				struct device_node *of_node)
>  {
>  	struct regulator_config cfg = {};
> +	int ret;
>  
>  	reg->base = reg_data->base;
>  	reg->type = reg_data->type;
> @@ -108,6 +178,28 @@ static int register_labibb_regulator(struct labibb_regulator *reg,
>  	reg->desc.poll_enabled_time = reg_data->poll_enabled_time;
>  	reg->desc.off_on_delay = LABIBB_OFF_ON_DELAY;
>  
> +	reg->sc_irq = -EINVAL;
> +	ret = of_irq_get_byname(of_node, "sc-err");
> +	if (ret < 0) {
> +		dev_err(reg->dev, "Unable to get sc-err, ret = %d\n",
> +			ret);
> +		return ret;
> +	} else
> +		reg->sc_irq = ret;
> +
> +	if (reg->sc_irq > 0) {
> +		ret = devm_request_threaded_irq(reg->dev,
> +						reg->sc_irq,
> +						NULL, labibb_sc_err_handler,
> +						IRQF_ONESHOT,
> +						"sc-err", reg);
> +		if (ret) {
> +			dev_err(reg->dev, "Failed to register sc-err irq ret=%d\n",
> +				ret);
> +			return ret;
> +		}
> +	}
> +
>  	cfg.dev = reg->dev;
>  	cfg.driver_data = reg;
>  	cfg.regmap = reg->regmap;
> -- 
> 2.26.2
>