From: Nisha Kumari <nishakum...@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 <nishakum...@codeaurora.org>
Signed-off-by: Sumit Semwal <sumit.sem...@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.
---
 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;
+       bool in_sc_err, reg_en, scp_done = false;
+
+       if (irq == labibb_reg->sc_irq)
+               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);
+       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) {
+
+               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 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,
+                       "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,
+                                               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;
+               }
+       }
+
        cfg.dev = labibb->dev;
        cfg.driver_data = reg;
        cfg.regmap = labibb->regmap;
-- 
2.26.2

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