Hello Lee, On 01/20/2015 06:11 PM, Javier Martinez Canillas wrote: >> >> But is it really a chardev? Don't chardevs usually live in >> drivers/char? It probably uses a chardev node in /dev, but what does >> it really do? What information can/will userspace obtain from this >> memory block? >> > > Right, is a driver that register a chardev but mostly to expose an ioctl > interface to send commands to the Embedded Controller from user-space. > > The Application Processor communicates with Embedded Controller by sending > commands over an interface. This can be either spi or i2c on ARM (depending > on the Chromebook model) or LPC on x86 Chromebooks so the platform driver > instantiated by the "cros-ec-dev" mfd cell is to allow user-space to send > commands to the Embedded Controller (using the correct transport method). > > So this chardev is used by the ectool binary in ChromeOS to communicate > with the Embedded Controller. > Just FYI, I'll rename it to "cros-ec-ctl" since as you said is not really a chardev but that just happens to be the interface chosen to send the ioctl commands to the driver. Thanks a lot for your suggestion. Best regards, Javier -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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