On Wed, Sep 23, 2015 at 02:29:06AM +0200, Sebastian Reichel wrote: > On Tue, Sep 22, 2015 at 05:10:45PM -0500, Andreas Dannenberg wrote: > > On Tue, Sep 22, 2015 at 09:16:49PM +0200, Sebastian Reichel wrote: > > > On Fri, Sep 18, 2015 at 04:39:57PM -0500, Andreas Dannenberg wrote: > > > > This patch allows reading (and writing, if the D+/D- USB signal-based > > > > charger type detection is disabled) of the input current limit through > > > > the power supply's input_current_limit sysfs property. This allows > > > > userspace to see what charger was detected and to re-configure the > > > > maximum current drawn from the external supply at runtime based on > > > > system-level knowledge or user input. > > > > > > Maybe also support writing into input_current_limit in auto mode. > > > Just disable auto detection until "auto" is written into sysfs node. > > > > Auto-detection was enabled by default in the original driver so I think > > that should be left intact. I added the ability to manually override > > this via DT with a fixed value, and then configure said fixed value > > through sysfs at runtime. > > > > I'm not 100% clear on the usecase of runtime enabling/disabling auto so > > I'd rather leave the implementation as-is. Either auto mode is enabled > > or not -- and this is directly tied to the DT setting. But if someone > > has a strong usecase for this I can certainly add it. > > For some usb power supplies auto-detection doesn't work very well, > resulting in a 100mA default fallback. Users knowing their hardware > could force charging with the correct input current limitation. Ok. So how should we best go about extending the usage of the 'input_current_limit' sysfs node for this charger? You mentioned writing 'auto' into it should enable the auto-detection mode. I suppose writing a fixed current value will disable it. But how to indicate to the user when reading 'input_current_limit' whether auto mode is enabled or not (I think this is something we should do). Can we return a mixed number/string like this? # Example: charger auto detection mode is disabled, and input current # limit is configured as 500mA. $ cat input_current_limit 500000 # Example: charger auto detection mode is enabled, and a charger # supporting 1A was detected (note the mixed number/string thats # returned) $ cat input_current_limit 1000000 (auto) Would that work? Or should we introduce a new sysfs property? -- Andreas Dannenberg Texas Instruments Inc -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
