power_supply: add CHARGE_COUNTER property and olpc_battery support for it

This adds PROP_CHARGE_COUNTER to the power supply class (documenting it
as well).  The OLPC battery driver uses this for spitting out its ACR
values (in uAh).  We have some rounding errors (the data sheet claims
416.7, the math actually works out to 416.666667, so we're forced to
choose between overflows or precision loss.  I chose precision loss,
and stuck w/ data sheet values), but I don't think anyone will care
that much.

Signed-off-by: Andres Salomon <dilinger@debian.org>
Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>

diff --git a/Documentation/power/power_supply_class.txt b/Documentation/power/power_supply_class.txt
index a8686e5a68579fc207d4c12e59246d7aee58ffcd..c6cd4956047c2f88c24ef5df0282193e885b6b3e 100644 (file)
--- a/Documentation/power/power_supply_class.txt
+++ b/Documentation/power/power_supply_class.txt
@@ -101,6 +101,10 @@ of charge when battery became full/empty". It also could mean "value of
 charge when battery considered full/empty at given conditions (temperature,
 age)". I.e. these attributes represents real thresholds, not design values.
 
+CHARGE_COUNTER - the current charge counter (in µAh).  This could easily
+be negative; there is no empty or full value.  It is only useful for
+relative, time-based measurements.
+
 ENERGY_FULL, ENERGY_EMPTY - same as above but for energy.
 
 CAPACITY - capacity in percents.

diff --git a/drivers/power/olpc_battery.c b/drivers/power/olpc_battery.c
index c8b596a7fc946c94e66f92b39a0d00d402edcfa7..9dd1589733c2270bfcae12e8f3f82e894165d04a 100644 (file)
--- a/drivers/power/olpc_battery.c
+++ b/drivers/power/olpc_battery.c
@@ -19,7 +19,7 @@
 
 #define EC_BAT_VOLTAGE 0x10    /* uint16_t,    *9.76/32,    mV   */
 #define EC_BAT_CURRENT 0x11    /* int16_t,     *15.625/120, mA   */
-#define EC_BAT_ACR     0x12
+#define EC_BAT_ACR     0x12    /* int16_t,     *416.7,      µAh  */
 #define EC_BAT_TEMP    0x13    /* uint16_t,    *100/256,   °C  */
 #define EC_AMB_TEMP    0x14    /* uint16_t,    *100/256,   °C  */
 #define EC_BAT_STATUS  0x15    /* uint8_t,     bitmask */
@@ -289,6 +289,14 @@ static int olpc_bat_get_property(struct power_supply *psy,
                ec_word = be16_to_cpu(ec_word);
                val->intval = ec_word * 100 / 256;
                break;
+       case POWER_SUPPLY_PROP_CHARGE_COUNTER:
+               ret = olpc_ec_cmd(EC_BAT_ACR, NULL, 0, (void *)&ec_word, 2);
+               if (ret)
+                       return ret;
+
+               ec_word = be16_to_cpu(ec_word);
+               val->intval = ec_word * 4167 / 10;
+               break;
        case POWER_SUPPLY_PROP_SERIAL_NUMBER:
                ret = olpc_ec_cmd(EC_BAT_SERIAL, NULL, 0, (void *)&ser_buf, 8);
                if (ret)
@@ -317,6 +325,7 @@ static enum power_supply_property olpc_bat_props[] = {
        POWER_SUPPLY_PROP_TEMP_AMBIENT,
        POWER_SUPPLY_PROP_MANUFACTURER,
        POWER_SUPPLY_PROP_SERIAL_NUMBER,
+       POWER_SUPPLY_PROP_CHARGE_COUNTER,
 };
 
 /* EEPROM reading goes completely around the power_supply API, sadly */

diff --git a/drivers/power/power_supply_sysfs.c b/drivers/power/power_supply_sysfs.c
index c444d6b10c581e9cb26ad9d110e6a3f34be35757..82e1246eeb0a480ad2e01d632c94b25d9b3f6334 100644 (file)
--- a/drivers/power/power_supply_sysfs.c
+++ b/drivers/power/power_supply_sysfs.c
@@ -99,6 +99,7 @@ static struct device_attribute power_supply_attrs[] = {
        POWER_SUPPLY_ATTR(charge_empty),
        POWER_SUPPLY_ATTR(charge_now),
        POWER_SUPPLY_ATTR(charge_avg),
+       POWER_SUPPLY_ATTR(charge_counter),
        POWER_SUPPLY_ATTR(energy_full_design),
        POWER_SUPPLY_ATTR(energy_empty_design),
        POWER_SUPPLY_ATTR(energy_full),

diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
index 68ed19ccf1f702c1978c8fb5e18ed557f316484c..ea96ead1d39daa0ac621d12ae28633e30e4c7f71 100644 (file)
--- a/include/linux/power_supply.h
+++ b/include/linux/power_supply.h
@@ -78,6 +78,7 @@ enum power_supply_property {
        POWER_SUPPLY_PROP_CHARGE_EMPTY,
        POWER_SUPPLY_PROP_CHARGE_NOW,
        POWER_SUPPLY_PROP_CHARGE_AVG,
+       POWER_SUPPLY_PROP_CHARGE_COUNTER,
        POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN,
        POWER_SUPPLY_PROP_ENERGY_EMPTY_DESIGN,
        POWER_SUPPLY_PROP_ENERGY_FULL,