staging: iio: cm3218: fix power management logic

use regulator_is_enabled to detect the state of regulator
rather than relying on regulator events. It may be possible
that some regulator events are missed i.e., before registering
the notifier.

Bug 1408639
Bug 1441626

Change-Id: I4ec516d3356df37e1c57a3d52e8790af669f4df1
Signed-off-by: Sri Krishna chowdary <schowdary@nvidia.com>
Reviewed-on: http://git-master/r/362632
Reviewed-on: http://git-master/r/365064
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Bharat Nihalani <bnihalani@nvidia.com>

diff --git a/drivers/staging/iio/light/cm3218.c b/drivers/staging/iio/light/cm3218.c
index e4d8f1f4d27d48e99c62cdd364e7544db56d0b1d..4114779c2157480569c78ee548e0db86f1b171da 100644 (file)
--- a/drivers/staging/iio/light/cm3218.c
+++ b/drivers/staging/iio/light/cm3218.c
@@ -4,7 +4,7 @@
  * IIO Light driver for monitoring ambient light intensity in lux and proximity
  * ir.
  *
- * Copyright (c) 2012-2013, NVIDIA CORPORATION. All rights reserved.
+ * Copyright (c) 2012-2014, NVIDIA CORPORATION. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
@@ -69,6 +69,8 @@ struct cm3218_chip {
        struct i2c_client               *client;
        const struct i2c_device_id      *id;
        struct regulator_bulk_data      *consumers;
+       struct workqueue_struct         *wq;
+       struct delayed_work             dw;
        struct notifier_block           regulator_nb;
        int                             i2c_xfer_state;
        struct regmap                   *regmap;
@@ -468,6 +470,29 @@ static int cm3218_activate_standby_mode(struct cm3218_chip *chip)
                                        CONFIGURE_SHDN_EN);
 }
 
+static void cm3218_work(struct work_struct *ws)
+{
+       struct cm3218_chip *chip;
+       struct iio_dev *indio_dev;
+
+       chip = container_of(ws, struct cm3218_chip, dw.work);
+       if (!chip->consumers)
+               return;
+
+       indio_dev = iio_priv_to_dev(chip);
+       mutex_lock(&indio_dev->mlock);
+       if (regulator_is_enabled(chip->consumers[0].consumer) &&
+               (chip->als_state == CHIP_POWER_OFF) &&
+               (chip->i2c_xfer_state != I2C_XFER_OK_REG_SYNC)) {
+               if (chip->i2c_xfer_state == I2C_XFER_NOT_ENABLED)
+                       chip->i2c_xfer_state = I2C_XFER_OK_REG_NOT_SYNC;
+               cm3218_activate_standby_mode(chip);
+       } else if (!regulator_is_enabled(chip->consumers[0].consumer)) {
+               chip->i2c_xfer_state = I2C_XFER_NOT_ENABLED;
+       }
+       mutex_unlock(&indio_dev->mlock);
+}
+
 /* this detects the regulator enable/disable event and puts
  * the device to low power state if this device does not use the regulator */
 static int cm3218_power_manager(struct notifier_block *regulator_nb,
@@ -476,15 +501,7 @@ static int cm3218_power_manager(struct notifier_block *regulator_nb,
        struct cm3218_chip *chip;
 
        chip = container_of(regulator_nb, struct cm3218_chip, regulator_nb);
-
-       if (event & (REGULATOR_EVENT_POST_ENABLE |
-                       REGULATOR_EVENT_OUT_POSTCHANGE)) {
-               chip->i2c_xfer_state = I2C_XFER_OK_REG_NOT_SYNC;
-               cm3218_activate_standby_mode(chip);
-       } else if (event & (REGULATOR_EVENT_DISABLE |
-                       REGULATOR_EVENT_FORCE_DISABLE)) {
-               chip->i2c_xfer_state = I2C_XFER_NOT_ENABLED;
-       }
+       queue_delayed_work(chip->wq, &chip->dw, 1);
        return NOTIFY_OK;
 }
 
@@ -615,6 +632,14 @@ static int cm3218_probe(struct i2c_client *client,
                chip->consumers = cm3218_consumers;
        }
 
+       chip->wq = create_singlethread_workqueue(id->name);
+       if (!chip->wq) {
+               dev_err(&client->dev, "%s workqueue err\n", __func__);
+               goto err_wq;
+       }
+
+       INIT_DELAYED_WORK(&chip->dw, cm3218_work);
+
        chip->regulator_nb.notifier_call = cm3218_power_manager;
        ret = regulator_register_notifier(chip->consumers[0].consumer,
                                        &chip->regulator_nb);
@@ -647,6 +672,8 @@ finish:
 unregister_regulator_notifier:
        regulator_unregister_notifier(chip->consumers[0].consumer,
                                        &chip->regulator_nb);
+err_wq:
+       destroy_workqueue(chip->wq);
 unregister_iio_dev:
        iio_device_unregister(indio_dev);
 free_iio_dev:
@@ -666,7 +693,9 @@ static void cm3218_shutdown(struct i2c_client *client)
 static int cm3218_remove(struct i2c_client *client)
 {
        struct iio_dev *indio_dev = i2c_get_clientdata(client);
+       struct cm3218_chip *chip = iio_priv(indio_dev);
 
+       destroy_workqueue(chip->wq);
        iio_device_unregister(indio_dev);
        iio_device_free(indio_dev);
        return 0;