From 70214ca74db36a7590a2c8d4fbdf3fe559543eb6 Mon Sep 17 00:00:00 2001 From: Cesar Santos Date: Thu, 16 Jan 2020 16:27:49 -0300 Subject: [PATCH] modules: power: Updating chg-iterm spec on documentation Most MOT batteries has 4.4V, but newer ones are 4.45V. Charging termination current ("taper") is dependent on battery specification plus capacity testing made by EE Team. So it can be something different than 97mA. Change-Id: Idecf02dc8d7175ae803f093ca02164de8e6673d6 Signed-off-by: Cesar Santos Reviewed-on: https://gerrit.mot.com/1484667 SLTApproved: Slta Waiver SME-Granted: SME Approvals Granted Tested-by: Jira Key Reviewed-by: Tiago Ganselli Reviewed-by: Ling Jin Submit-Approved: Jira Key --- drivers/power/qpnp-smbcharger-mmi/README | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/drivers/power/qpnp-smbcharger-mmi/README b/drivers/power/qpnp-smbcharger-mmi/README index 18c6a2283697..e01ce089fe41 100644 --- a/drivers/power/qpnp-smbcharger-mmi/README +++ b/drivers/power/qpnp-smbcharger-mmi/README @@ -135,7 +135,9 @@ charging. Current is always tapered when voltage achieves maximum voltage specification (which is generally 4.4V, but may have a different value, depending a product -battery specs). It is tapered to 97mA, as IEEE specifies. +battery specs). It is tapered to some small value, possibly around 100mA, +which is based on product specifications and capacity testing, defined by +EE (Electrical Engineering) Team/Hardware. If temperature is below -20 degC or above 60 degC, it should automatically stop charging device. @@ -162,12 +164,12 @@ any commercial product that has a lithium-ion battery embedded or plugged to it). NOTE2: taper current mostly refers to when battery is above maximum allowed -voltage on a specific temperature region, based on rules above (which is 97mA -as current specification). So be aware that the rest of this document may -refer as "taper" to a current that is limiting the maximum value, but before -achieving a staget in which current is limited to 97mA (so an intermediate -stage). Also "taper voltage" will refer to a voltage level in which this -mentioned "taper" current (intermediate current level) is triggered. +voltage on a specific temperature region, based on rules above. So be aware +that the rest of this document may refer as "taper" to a current that is +limiting the maximum value, but before achieving a stage in which current +is limited to something around 100mA (so an intermediate stage). Also +"taper voltage" will refer to a voltage level in which this mentioned +"taper" current (intermediate current level) is triggered. ========================================= @@ -228,7 +230,7 @@ STEP_NONE: no charger present STEP_STOP: in zone hot or zone cold, which limits charging considerably STEP_NORM: limits current to some value STEP_MAX: allows maximum current value, when in between 0 and 45 degC -STEP_FULL: battery is almost or completely full, tapering to 97mA +STEP_FULL: battery is almost or completely full, tapering to a small current STEP_FLOAT: TODO Important to note that even when moving from one state to another, temperature @@ -240,7 +242,8 @@ range device is. sysfs). "taper_ma" is "fcc_norm_ma" in case is in STATE_MAX, which means battery is above taper voltage. If in any other state, it will refer to "chrg_iterm", -which is equal to 97mA as current standards. +which will depend on device specifications (4.4V batteries have 97mA as +current standards, and 4.45V batteries have 121mA as taper current). Now, let's check the algorithms for a bit: