[PATCH v8 4/5] power: supply: max17040: Config alert SOC low level threshold from FDT

Matheus Castello
2019-12-05T16:07:59Z

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>
---
drivers/power/supply/max17040_battery.c | 52 ++++++++++++++++++++++++-
1 file changed, 51 insertions(+), 1 deletion(-)

diff --git a/drivers/power/supply/max17040_battery.c b/drivers/power/supply/max17040_battery.c
index 5a8cd365a61e..2a2a1fd8d4eb 100644
--- 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) {
--
2.24.0.rc2