power: supply: ltc2941-battery-gauge: Add LTC2944 support

LTC2944 is compatible with LTC2943, but uses different
voltage and current computing constants.

Signed-off-by: Dragos Bogdan <dragos.bogdan@analog.com>
Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Tested-by: Dragos Bogdan <dragos.bogdan@analog.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>

diff --git a/Documentation/devicetree/bindings/power/supply/ltc2941.txt b/Documentation/devicetree/bindings/power/supply/ltc2941.txt
index 8ec10366295d3ec92381581f162c96861284d3cb..3b9ba147b04171c748cfd4aaac12c6d8692a85d0 100644 (file)
--- a/Documentation/devicetree/bindings/power/supply/ltc2941.txt
+++ b/Documentation/devicetree/bindings/power/supply/ltc2941.txt
@@ -1,14 +1,14 @@
-binding for LTC2941, LTC2942 and LTC2943 battery gauges
+binding for LTC2941, LTC2942, LTC2943 and LTC2944 battery gauges
 
 All chips measure battery capacity.
 The LTC2942 is pin compatible with the LTC2941, it adds voltage and
-temperature monitoring, and is runtime detected. LTC2943 is software
-compatible, uses a slightly different conversion formula for the
-charge counter and adds voltage, current and temperature monitoring.
+temperature monitoring, and is runtime detected. LTC2943 and LTC2944
+is software compatible, uses a slightly different conversion formula
+for the charge counter and adds voltage, current and temperature monitoring.
 
 Required properties:
-- compatible: Should contain "lltc,ltc2941", "lltc,ltc2942" or "lltc,ltc2943"
-    which also indicates the type of I2C chip attached.
+- compatible: Should contain "lltc,ltc2941", "lltc,ltc2942", "lltc,ltc2943"
+    or "lltc,ltc2944" which also indicates the type of I2C chip attached.
 - reg: The 7-bit I2C address.
 - lltc,resistor-sense: The sense resistor value in milli-ohms. Can be a 32-bit
     negative value when the battery has been connected to the wrong end of the

diff --git a/drivers/power/supply/ltc2941-battery-gauge.c b/drivers/power/supply/ltc2941-battery-gauge.c
index 42ff4e3daf3523d605a823e5b5389e51cca90a9b..08e4fd9ee6074717a35fdbe9f113e1e3b430a31f 100644 (file)
--- a/drivers/power/supply/ltc2941-battery-gauge.c
+++ b/drivers/power/supply/ltc2941-battery-gauge.c
@@ -1,6 +1,6 @@
 /*
- * I2C client/driver for the Linear Technology LTC2941, LTC2942 and LTC2943
- * Battery Gas Gauge IC
+ * I2C client/driver for the Linear Technology LTC2941, LTC2942, LTC2943
+ * and LTC2944 Battery Gas Gauge IC
  *
  * Copyright (C) 2014 Topic Embedded Systems
  *
@@ -48,6 +48,7 @@ enum ltc294x_id {
        LTC2941_ID,
        LTC2942_ID,
        LTC2943_ID,
+       LTC2944_ID,
 };
 
 #define LTC2941_REG_STATUS_CHIP_ID     BIT(7)
@@ -153,7 +154,8 @@ static int ltc294x_reset(const struct ltc294x_info *info, int prescaler_exp)
        case LTC2942_ID:        /* 2942 measures every 2 sec */
                control |= LTC2942_REG_CONTROL_MODE_SCAN;
                break;
-       case LTC2943_ID:        /* 2943 measures every 10 sec */
+       case LTC2943_ID:
+       case LTC2944_ID:        /* 2943 and 2944 measure every 10 sec */
                control |= LTC2943_REG_CONTROL_MODE_SCAN;
                break;
        default:
@@ -269,6 +271,11 @@ static int ltc294x_get_voltage(const struct ltc294x_info *info, int *val)
                value /= 0xFFFF;
                value *= 1000 / 2;
                break;
+       case LTC2944_ID:
+               value *= 70800 / 5*4;
+               value /= 0xFFFF;
+               value *= 1000 * 5/4;
+               break;
        default:
                value *= 6000 * 10;
                value /= 0xFFFF;
@@ -289,10 +296,14 @@ static int ltc294x_get_current(const struct ltc294x_info *info, int *val)
                LTC2943_REG_CURRENT_MSB, &datar[0], 2);
        value = (datar[0] << 8) | datar[1];
        value -= 0x7FFF;
+       if (info->id == LTC2944_ID)
+               value *= 64000;
+       else
+               value *= 60000;
        /* Value is in range -32k..+32k, r_sense is usually 10..50 mOhm,
         * the formula below keeps everything in s32 range while preserving
         * enough digits */
-       *val = 1000 * ((60000 * value) / (info->r_sense * 0x7FFF)); /* in uA */
+       *val = 1000 * (value / (info->r_sense * 0x7FFF)); /* in uA */
        return ret;
 }
 
@@ -470,6 +481,7 @@ static int ltc294x_i2c_probe(struct i2c_client *client,
        info->supply_desc.type = POWER_SUPPLY_TYPE_BATTERY;
        info->supply_desc.properties = ltc294x_properties;
        switch (info->id) {
+       case LTC2944_ID:
        case LTC2943_ID:
                info->supply_desc.num_properties =
                        ARRAY_SIZE(ltc294x_properties);
@@ -543,6 +555,7 @@ static const struct i2c_device_id ltc294x_i2c_id[] = {
        { "ltc2941", LTC2941_ID, },
        { "ltc2942", LTC2942_ID, },
        { "ltc2943", LTC2943_ID, },
+       { "ltc2944", LTC2944_ID, },
        { },
 };
 MODULE_DEVICE_TABLE(i2c, ltc294x_i2c_id);
@@ -560,6 +573,10 @@ static const struct of_device_id ltc294x_i2c_of_match[] = {
                .compatible = "lltc,ltc2943",
                .data = (void *)LTC2943_ID,
        },
+       {
+               .compatible = "lltc,ltc2944",
+               .data = (void *)LTC2944_ID,
+       },
        { },
 };
 MODULE_DEVICE_TABLE(of, ltc294x_i2c_of_match);
@@ -578,5 +595,5 @@ module_i2c_driver(ltc294x_driver);
 
 MODULE_AUTHOR("Auryn Verwegen, Topic Embedded Systems");
 MODULE_AUTHOR("Mike Looijmans, Topic Embedded Products");
-MODULE_DESCRIPTION("LTC2941/LTC2942/LTC2943 Battery Gas Gauge IC driver");
+MODULE_DESCRIPTION("LTC2941/LTC2942/LTC2943/LTC2944 Battery Gas Gauge IC driver");
 MODULE_LICENSE("GPL");