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>
    [sumits: updated to rework to use regmap_read_poll_timeout, handle it per
             regulator, add REGULATOR_EVENT_OVER_CURRENT handling and
             notification to clients and other cleanup]
--
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.
v4: sumits: updated 'int vreg_enabled' to 'boot enabled', made sc_irq a local 
var
     and other review comments from v3.
---
 drivers/regulator/qcom-labibb-regulator.c | 102 +++++++++++++++++++++-
 1 file changed, 99 insertions(+), 3 deletions(-)

diff --git a/drivers/regulator/qcom-labibb-regulator.c 
b/drivers/regulator/qcom-labibb-regulator.c
index 33b764ac69d1..bca0308b26dd 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 +29,16 @@
 #define IBB_ENABLE_TIME                        (LABIBB_OFF_ON_DELAY * 10)
 #define LABIBB_POLL_ENABLED_TIME       1000
 
+#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;
+       bool                            enabled;
        u8                              type;
 };
 
@@ -59,12 +65,26 @@ static int qcom_labibb_regulator_is_enabled(struct 
regulator_dev *rdev)
 
 static int qcom_labibb_regulator_enable(struct regulator_dev *rdev)
 {
-       return regulator_enable_regmap(rdev);
+       int ret;
+       struct labibb_regulator *reg = rdev_get_drvdata(rdev);
+
+       ret = regulator_enable_regmap(rdev);
+       if (ret >= 0)
+               reg->enabled = true;
+
+       return ret;
 }
 
 static int qcom_labibb_regulator_disable(struct regulator_dev *rdev)
 {
-       return regulator_disable_regmap(rdev);
+       int ret = 0;
+       struct labibb_regulator *reg = rdev_get_drvdata(rdev);
+
+       ret = regulator_disable_regmap(rdev);
+       if (ret >= 0)
+               reg->enabled = false;
+
+       return ret;
 }
 
 static struct regulator_ops qcom_labibb_ops = {
@@ -73,12 +93,70 @@ 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) {
+
+               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->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 struct regulator_dev *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;
+       int ret, sc_irq;
 
        reg->base = reg_data->base;
        reg->type = reg_data->type;
@@ -95,6 +173,24 @@ static struct regulator_dev 
*register_labibb_regulator(struct labibb_regulator *
        reg->desc.poll_enabled_time = LABIBB_POLL_ENABLED_TIME;
        reg->desc.off_on_delay = LABIBB_OFF_ON_DELAY;
 
+       sc_irq = of_irq_get_byname(of_node, "sc-err");
+       if (sc_irq < 0) {
+               dev_err(reg->dev, "Unable to get sc-err, ret = %d\n",
+                       sc_irq);
+               return ERR_PTR(sc_irq);
+       } else {
+               ret = devm_request_threaded_irq(reg->dev,
+                                               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 ERR_PTR(ret);
+               }
+       }
+
        cfg.dev = reg->dev;
        cfg.driver_data = reg;
        cfg.regmap = reg->regmap;
-- 
2.26.2

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