power: supply: max17040: Support soc alert

max17048 and max17049 support SOC alerts (interrupts when battery
capacity changes by +/- 1%). At the moment the driver polls for changes
every second. Using the alerts removes the need for polling.

Signed-off-by: Iskren Chernev <iskren.chernev@gmail.com>
Tested-by: Jonathan Bakker <xc-racer2@live.ca>
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 ae39ca5c6753e805a53026b3f81b332131e79a81..1d7510a59295d466f9b674d48372724ee7a1363a 100644 (file)
--- a/drivers/power/supply/max17040_battery.c
+++ b/drivers/power/supply/max17040_battery.c
@@ -25,6 +25,7 @@
 #define MAX17040_MODE  0x06
 #define MAX17040_VER   0x08
 #define MAX17040_CONFIG        0x0C
+#define MAX17040_STATUS        0x1A
 #define MAX17040_CMD   0xFE
 
 
@@ -33,7 +34,10 @@
 #define MAX17040_RCOMP_DEFAULT  0x9700
 
 #define MAX17040_ATHD_MASK             0x3f
+#define MAX17040_ALSC_MASK             0x40
 #define MAX17040_ATHD_DEFAULT_POWER_UP 4
+#define MAX17040_STATUS_HD_MASK                0x1000
+#define MAX17040_STATUS_SC_MASK                0x2000
 #define MAX17040_CFG_RCOMP_MASK                0xff00
 
 enum chip_id {
@@ -55,6 +59,7 @@ struct chip_data {
        u16 vcell_div;
        u8  has_low_soc_alert;
        u8  rcomp_bytes;
+       u8  has_soc_alert;
 };
 
 static struct chip_data max17040_family[] = {
@@ -65,6 +70,7 @@ static struct chip_data max17040_family[] = {
                .vcell_div = 1,
                .has_low_soc_alert = 0,
                .rcomp_bytes = 2,
+               .has_soc_alert = 0,
        },
        [ID_MAX17041] = {
                .reset_val = 0x0054,
@@ -73,6 +79,7 @@ static struct chip_data max17040_family[] = {
                .vcell_div = 1,
                .has_low_soc_alert = 0,
                .rcomp_bytes = 2,
+               .has_soc_alert = 0,
        },
        [ID_MAX17043] = {
                .reset_val = 0x0054,
@@ -81,6 +88,7 @@ static struct chip_data max17040_family[] = {
                .vcell_div = 1,
                .has_low_soc_alert = 1,
                .rcomp_bytes = 1,
+               .has_soc_alert = 0,
        },
        [ID_MAX17044] = {
                .reset_val = 0x0054,
@@ -89,6 +97,7 @@ static struct chip_data max17040_family[] = {
                .vcell_div = 1,
                .has_low_soc_alert = 1,
                .rcomp_bytes = 1,
+               .has_soc_alert = 0,
        },
        [ID_MAX17048] = {
                .reset_val = 0x5400,
@@ -97,6 +106,7 @@ static struct chip_data max17040_family[] = {
                .vcell_div = 8,
                .has_low_soc_alert = 1,
                .rcomp_bytes = 1,
+               .has_soc_alert = 1,
        },
        [ID_MAX17049] = {
                .reset_val = 0x5400,
@@ -105,6 +115,7 @@ static struct chip_data max17040_family[] = {
                .vcell_div = 4,
                .has_low_soc_alert = 1,
                .rcomp_bytes = 1,
+               .has_soc_alert = 1,
        },
        [ID_MAX17058] = {
                .reset_val = 0x5400,
@@ -113,6 +124,7 @@ static struct chip_data max17040_family[] = {
                .vcell_div = 8,
                .has_low_soc_alert = 1,
                .rcomp_bytes = 1,
+               .has_soc_alert = 0,
        },
        [ID_MAX17059] = {
                .reset_val = 0x5400,
@@ -121,6 +133,7 @@ static struct chip_data max17040_family[] = {
                .vcell_div = 4,
                .has_low_soc_alert = 1,
                .rcomp_bytes = 1,
+               .has_soc_alert = 0,
        },
 };
 
@@ -156,6 +169,12 @@ static int max17040_set_low_soc_alert(struct max17040_chip *chip, u32 level)
                        MAX17040_ATHD_MASK, level);
 }
 
+static int max17040_set_soc_alert(struct max17040_chip *chip, bool enable)
+{
+       return regmap_update_bits(chip->regmap, MAX17040_CONFIG,
+                       MAX17040_ALSC_MASK, enable ? MAX17040_ALSC_MASK : 0);
+}
+
 static int max17040_set_rcomp(struct max17040_chip *chip, u16 rcomp)
 {
        u16 mask = chip->data.rcomp_bytes == 2 ?
@@ -300,11 +319,33 @@ static void max17040_work(struct work_struct *work)
        max17040_queue_work(chip);
 }
 
+/* Returns true if alert cause was SOC change, not low SOC */
+static bool max17040_handle_soc_alert(struct max17040_chip *chip)
+{
+       bool ret = true;
+       u32 data;
+
+       regmap_read(chip->regmap, MAX17040_STATUS, &data);
+
+       if (data & MAX17040_STATUS_HD_MASK) {
+               // this alert was caused by low soc
+               ret = false;
+       }
+       if (data & MAX17040_STATUS_SC_MASK) {
+               // soc change bit -- deassert to mark as handled
+               regmap_write(chip->regmap, MAX17040_STATUS,
+                               data & ~MAX17040_STATUS_SC_MASK);
+       }
+
+       return ret;
+}
+
 static irqreturn_t max17040_thread_handler(int id, void *dev)
 {
        struct max17040_chip *chip = dev;
 
-       dev_warn(&chip->client->dev, "IRQ: Alert battery low level");
+       if (!(chip->data.has_soc_alert && max17040_handle_soc_alert(chip)))
+               dev_warn(&chip->client->dev, "IRQ: Alert battery low level\n");
 
        /* read registers */
        max17040_check_changes(chip);
@@ -428,6 +469,7 @@ static int max17040_probe(struct i2c_client *client,
        struct power_supply_config psy_cfg = {};
        struct max17040_chip *chip;
        enum chip_id chip_id;
+       bool enable_irq = false;
        int ret;
 
        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
@@ -479,6 +521,27 @@ static int max17040_probe(struct i2c_client *client,
                        return ret;
                }
 
+               enable_irq = true;
+       }
+
+       if (client->irq && chip->data.has_soc_alert) {
+               ret = max17040_set_soc_alert(chip, 1);
+               if (ret) {
+                       dev_err(&client->dev,
+                               "Failed to set SOC alert: err %d\n", ret);
+                       return ret;
+               }
+               enable_irq = true;
+       } else {
+               /* soc alerts negate the need for polling */
+               INIT_DEFERRABLE_WORK(&chip->work, max17040_work);
+               ret = devm_add_action(&client->dev, max17040_stop_work, chip);
+               if (ret)
+                       return ret;
+               max17040_queue_work(chip);
+       }
+
+       if (enable_irq) {
                ret = max17040_enable_alert_irq(chip);
                if (ret) {
                        client->irq = 0;
@@ -487,12 +550,6 @@ static int max17040_probe(struct i2c_client *client,
                }
        }
 
-       INIT_DEFERRABLE_WORK(&chip->work, max17040_work);
-       ret = devm_add_action(&client->dev, max17040_stop_work, chip);
-       if (ret)
-               return ret;
-       max17040_queue_work(chip);
-
        return 0;
 }
 
@@ -503,7 +560,11 @@ static int max17040_suspend(struct device *dev)
        struct i2c_client *client = to_i2c_client(dev);
        struct max17040_chip *chip = i2c_get_clientdata(client);
 
-       cancel_delayed_work(&chip->work);
+       if (client->irq && chip->data.has_soc_alert)
+               // disable soc alert to prevent wakeup
+               max17040_set_soc_alert(chip, 0);
+       else
+               cancel_delayed_work(&chip->work);
 
        if (client->irq && device_may_wakeup(dev))
                enable_irq_wake(client->irq);
@@ -519,7 +580,10 @@ static int max17040_resume(struct device *dev)
        if (client->irq && device_may_wakeup(dev))
                disable_irq_wake(client->irq);
 
-       max17040_queue_work(chip);
+       if (client->irq && chip->data.has_soc_alert)
+               max17040_set_soc_alert(chip, 1);
+       else
+               max17040_queue_work(chip);
 
        return 0;
 }