On Fri, Jan 27, 2017 at 09:54:33AM +0100, Quentin Schulz wrote: > The X-Powers AXP20X and AXP22X PMICs have multiple ADCs. They expose > information and data of the various power supplies they support such as > ACIN, battery and VBUS. For example, they expose the current battery > voltage, charge or discharge, as well as ACIN and VBUS current voltages > and currents, internal PMIC temperature and ADC on 2 different GPIOs > when in the right mode (for the AXP209 only). > > The ACIN power supply driver is added by this patch. The AXP20X and > AXP22X can both read the status and the "usability" of the power supply > but only the AXP209 will be able to tell the current current and voltage > of the power supply by reading ADC channels. It is simply not supported > by the AXP22X PMICs. > > The battery power supply driver is also added by this patch. The AXP20X > and AXP22X share most of their behaviour but have slight variations. The > allowed target voltages for battery charging are not the same, the > AXP22X PMIC are able to tell if the battery percentage computed by the > PMIC is trustworthy and they have different formulas for computing max > current for battery power supply. The driver is able to give the current > voltage and current of the battery (be it charging or discharging), the > maximal and minimal voltage and maximal current allowed for the battery, > whether the battery is present and usable and its capacity. It will get > the battery current current and voltage by reading the ADC channels. The > PMIC allows maximal voltages (4.36V for AXP20X and 4.22V and 4.24V for > AXP22X) that should not be used with Lithium-based batteries and since > this PMIC is supposed to be used with Lithium-based batteries, they have > been disabled. The values returned by the ADC driver are multipled by > 1000 to scale from the mV returned by the ADC to the uV expected by the > power supply framework. > > This series of patch adds DT bindings for ACIN power supply, ADC and > battery power supply drivers for AXP20X and AXP22X PMICs and their > documentation. It also enables the supported power supplies for the > Nextthing Co. CHIP and Sinlinx SinA33 boards. > > The different drivers are also added to the MFD cells of the AXP20X and > AXP22X cells and the writeable and volatile regs updated to work with > the newly added drivers. > > VBUS driver has intentionally not been modified to use the ADC channels > because a DT binding already exists for this driver. Migrating the > driver would mean to add an iio_map to map the ADC channels to the VBUS > driver (so we can use iio_channel_get and iio_read_channel_processed > functions). This slightly complexifies the VBUS driver only for > "cosmetic" changes. Feel free to give your two cents on the matter. > > This series of patch is based on a previous upstreaming attempt done by > Bruno Prémont few months ago. It differs in three points: the ADC > driver does not tell the battery temperature (TS_IN) as I do not have a > board to test it with, it does not tell the instantaneous battery power > as it returns crazy values for me and finally no support for OCV curves > for the battery. > > You can test these patches from this repo and branch: > https://github.com/QSchulz/linux/tree/axp2xx_adc_batt_ac_v2 For the whole serie, Acked-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx> Maxime -- Maxime Ripard, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com
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