[PORT FROM R2]max17042: block maxim registers reads during reboot

BZ: 15870

This patch blocks the maxim register reads during reboot, as
the chip cannot be recovered if the i2c transaction is broken.

Change-Id: I2dceba9ba9d863e3b6cf36b46f821ec4d26cf5a7
R2-Change-Id: I889135b8e76717d1fcbb742eca2e9ecccc9ac086
Signed-off-by: Ramakrishna Pallala <ramakrishna.pallala@intel.com>
Reviewed-on: http://android.intel.com:8080/32753
Reviewed-by: Mendi, EduardoX <eduardox.mendi@intel.com>
Tested-by: Mendi, EduardoX <eduardox.mendi@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>

diff --git a/drivers/power/max17042_battery.c b/drivers/power/max17042_battery.c
index 1442bf3..6703f7c 100644 (file)
--- a/drivers/power/max17042_battery.c
+++ b/drivers/power/max17042_battery.c
@@ -250,6 +250,8 @@ struct max17042_chip {
        int technology;
        int charge_full_des;
        struct delayed_work init_worker;
+
+       bool plat_rebooting;
 };
 
 #ifdef CONFIG_DEBUG_FS
@@ -291,6 +293,16 @@ static enum power_supply_property max17042_battery_props[] = {
 static int max17042_write_reg(struct i2c_client *client, u8 reg, u16 value)
 {
        int ret, i;
+       struct max17042_chip *chip = i2c_get_clientdata(client);
+
+       /* if the shutdown or reboot sequence started
+        * then block the access to maxim registers as chip
+        * cannot be recovered from broken i2c transactions
+        */
+       if (chip->plat_rebooting) {
+               dev_warn(&client->dev, "rebooting is in progress\n");
+               return -EINVAL;
+       }
 
        for (i = 0; i < NR_RETRY_CNT; i++) {
                ret = i2c_smbus_write_word_data(client, reg, value);
@@ -309,6 +321,16 @@ static int max17042_write_reg(struct i2c_client *client, u8 reg, u16 value)
 static int max17042_read_reg(struct i2c_client *client, u8 reg)
 {
        int ret, i;
+       struct max17042_chip *chip = i2c_get_clientdata(client);
+
+       /* if the shutdown or reboot sequence started
+        * then block the access to maxim registers as chip
+        * cannot be recovered from broken i2c transactions
+        */
+       if (chip->plat_rebooting) {
+               dev_warn(&client->dev, "rebooting is in progress\n");
+               return -EINVAL;
+       }
 
        for (i = 0; i < NR_RETRY_CNT; i++) {
                ret = i2c_smbus_read_word_data(client, reg);
@@ -338,8 +360,12 @@ static int max17042_write_verify_reg(struct i2c_client *client,
        for (i = 0; i < NR_RETRY_CNT; i++) {
                /* Write the value to register */
                ret = max17042_write_reg(client, reg, value);
+               if (ret < 0)
+                       continue;
                /* Read the value from register */
                ret = max17042_read_reg(client, reg);
+               if (ret < 0)
+                       continue;
                /* compare the both the values */
                if (value != ret)
                        dev_err(&client->dev,
@@ -354,17 +380,18 @@ static int max17042_write_verify_reg(struct i2c_client *client,
 static int max17042_reg_read_modify(struct i2c_client *client, u8 reg,
                                                        u16 val, int bit_set)
 {
-       u16 data;
        int ret;
 
-       data = max17042_read_reg(client, reg);
+       ret = max17042_read_reg(client, reg);
+       if (ret < 0)
+               return ret;
 
        if (bit_set)
-               data |= val;
+               ret |= val;
        else
-               data &= (~val);
+               ret &= (~val);
 
-       ret = max17042_write_reg(client, reg, data);
+       ret = max17042_write_reg(client, reg, ret);
        return ret;
 }
 
@@ -956,17 +983,6 @@ static void restore_runtime_params(struct max17042_chip *chip)
                                                fg_conf_data->cycles);
 }
 
-static int max17042_reboot_callback(struct notifier_block *nfb,
-                                       unsigned long event, void *data)
-{
-       struct max17042_chip *chip = i2c_get_clientdata(max17042_client);
-
-       if (chip->pdata->enable_current_sense)
-               save_runtime_params(chip);
-
-       return NOTIFY_OK;
-}
-
 static int init_max17042_chip(struct max17042_chip *chip)
 {
        int ret = 0, val;
@@ -1548,6 +1564,25 @@ static struct i2c_driver max17042_i2c_driver = {
        .id_table       = max17042_id,
 };
 
+static int max17042_reboot_callback(struct notifier_block *nfb,
+                                       unsigned long event, void *data)
+{
+       struct max17042_chip *chip = i2c_get_clientdata(max17042_client);
+
+       if (chip->pdata->enable_current_sense)
+               save_runtime_params(chip);
+
+       /* if the shutdown or reboot sequence started
+        * then block the access to maxim registers as chip
+        * cannot be recovered from broken i2c transactions
+        */
+       mutex_lock(&chip->batt_lock);
+       chip->plat_rebooting = true;
+       mutex_unlock(&chip->batt_lock);
+
+       return NOTIFY_OK;
+}
+
 static int __init max17042_init(void)
 {
        return i2c_add_driver(&max17042_i2c_driver);