power: supply: max17040: Config alert SOC low level threshold from FDT

For configuration of fuel gauge alert for a low level state of charge
interrupt we add a function to config level threshold and a device tree
binding property to set it in flatned device tree node.

Now we can use "maxim,alert-low-soc-level" property with the values from
1% up to 32% to configure alert interrupt threshold.

Signed-off-by: Matheus Castello <matheus@castello.eng.br>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

diff --git a/drivers/power/supply/max17040_battery.c b/drivers/power/supply/max17040_battery.c
index 5a8cd36..2a2a1fd 100644 (file)
--- a/drivers/power/supply/max17040_battery.c
+++ b/drivers/power/supply/max17040_battery.c
@@ -29,6 +29,9 @@
 #define MAX17040_DELAY         1000
 #define MAX17040_BATTERY_FULL  95
 
+#define MAX17040_ATHD_MASK             0xFFC0
+#define MAX17040_ATHD_DEFAULT_POWER_UP 4
+
 struct max17040_chip {
        struct i2c_client               *client;
        struct delayed_work             work;
@@ -43,6 +46,8 @@ struct max17040_chip {
        int soc;
        /* State Of Charge */
        int status;
+       /* Low alert threshold from 32% to 1% of the State of Charge */
+       u32 low_soc_alert;
 };
 
 static int max17040_get_property(struct power_supply *psy,
@@ -99,6 +104,21 @@ static void max17040_reset(struct i2c_client *client)
        max17040_write_reg(client, MAX17040_CMD, 0x0054);
 }
 
+static int max17040_set_low_soc_alert(struct i2c_client *client, u32 level)
+{
+       int ret;
+       u16 data;
+
+       level = 32 - level;
+       data = max17040_read_reg(client, MAX17040_RCOMP);
+       /* clear the alrt bit and set LSb 5 bits */
+       data &= MAX17040_ATHD_MASK;
+       data |= level;
+       ret = max17040_write_reg(client, MAX17040_RCOMP, data);
+
+       return ret;
+}
+
 static void max17040_get_vcell(struct i2c_client *client)
 {
        struct max17040_chip *chip = i2c_get_clientdata(client);
@@ -161,6 +181,21 @@ static void max17040_get_status(struct i2c_client *client)
                chip->status = POWER_SUPPLY_STATUS_FULL;
 }
 
+static int max17040_get_of_data(struct max17040_chip *chip)
+{
+       struct device *dev = &chip->client->dev;
+
+       chip->low_soc_alert = MAX17040_ATHD_DEFAULT_POWER_UP;
+       device_property_read_u32(dev,
+                                "maxim,alert-low-soc-level",
+                                &chip->low_soc_alert);
+
+       if (chip->low_soc_alert <= 0 || chip->low_soc_alert >= 33)
+               return -EINVAL;
+
+       return 0;
+}
+
 static void max17040_check_changes(struct i2c_client *client)
 {
        max17040_get_vcell(client);
@@ -192,6 +227,9 @@ static irqreturn_t max17040_thread_handler(int id, void *dev)
        /* send uevent */
        power_supply_changed(chip->battery);
 
+       /* reset alert bit */
+       max17040_set_low_soc_alert(client, chip->low_soc_alert);
+
        return IRQ_HANDLED;
 }
 
@@ -230,6 +268,7 @@ static int max17040_probe(struct i2c_client *client,
        struct i2c_adapter *adapter = client->adapter;
        struct power_supply_config psy_cfg = {};
        struct max17040_chip *chip;
+       int ret;
 
        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
                return -EIO;
@@ -240,6 +279,12 @@ static int max17040_probe(struct i2c_client *client,
 
        chip->client = client;
        chip->pdata = client->dev.platform_data;
+       ret = max17040_get_of_data(chip);
+       if (ret) {
+               dev_err(&client->dev,
+                       "failed: low SOC alert OF data out of bounds\n");
+               return ret;
+       }
 
        i2c_set_clientdata(client, chip);
        psy_cfg.drv_data = chip;
@@ -257,7 +302,12 @@ static int max17040_probe(struct i2c_client *client,
        /* check interrupt */
        if (client->irq && of_device_is_compatible(client->dev.of_node,
                                                   "maxim,max77836-battery")) {
-               int ret;
+               ret = max17040_set_low_soc_alert(client, chip->low_soc_alert);
+               if (ret) {
+                       dev_err(&client->dev,
+                               "Failed to set low SOC alert: err %d\n", ret);
+                       return ret;
+               }
 
                ret = max17040_enable_alert_irq(chip);
                if (ret) {