Hi Linus, On 26 September 2018 at 16:09, Linus Walleij <linus.walleij@xxxxxxxxxx> wrote: > On Wed, Sep 26, 2018 at 5:00 AM Baolin Wang <baolin.wang@xxxxxxxxxx> wrote: > >> This patch adds the Spreadtrum SC27XX serial PMICs fuel gauge support, >> which is used to calculate the battery capacity. >> >> Original-by: Yuanjiang Yu <yuanjiang.yu@xxxxxxxxxx> >> Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxx> >> --- >> Changes from v1: >> - Use battery standard properties to get internal resistance and ocv table. >> - Change devm_gpiod_get_optional() to devm_gpiod_get(). >> - Add power_supply_changed() when detecting battery present change. >> - Return micro volts for sc27xx_fgu_get_vbat_ocv(). > > Acked-by: Linus Walleij <linus.walleij@xxxxxxxxxx> > > I see that you need to have the internal resistance as parameter to > this equation so it needs to come in. (I guess as factor/typical > internal resistance as suggested.) > > IIUC this reliance on an uncertain internal resistance is the reason > why fuel gauges / coloumb counters are seen as crude ways to > estimate battery capacity, and their accuracy and reliability worsen > over the lifetime of the battery, and this is why safety-critical devices > include ways to measure the internal resistance as well. Yes. Thanks for your reviewing. > > But the hardware is as it is, and probably for some good reasons, > like cost. > > Yours, > Linus Walleij -- Baolin Wang Best Regards
