Hi Sebastian, >>>> BT_DISABLE_N is the name of this pin in the datasheet of the QCA chip, >>>> not on the board, so this name is the same regardless of what you name >>>> the line or gpio your board connect it to. >>> >>> and QCA chip v1 and QCA chip v2 will use the same driver and >>> same firmware loading mechanism. So why do we have to add a new >>> GPIO naming if they decide to change the name in the data sheet. >>> With Bluetooth it is pretty much all the same. Every UART chip >>> has a shutdown/reset GPIO to enable/disable the chip behind the >>> UART. >>> >>>>> A new board should not require driver changes, you just ship a new DT >>>>> for that board and an existing driver hopefully just does the job. No >>>>> matter how someone named a GPIO in a piece of paper. >>>>> >>>> >>>> I totally agree with the fact that the board should not affect the >>>> naming of the gpio in the driver. But I do enjoy when we refer to pins >>>> by their real name - instead of having to guess which pin in the _chip_ >>>> specification the driver actually refer to. >>>> >>>> >>>> That said, what name would you prefer for this? >>>> >>>> Afaict this is not "wakeup" and there are a few extra steps between the >>>> disabled state and "bluetooth is enabled", so "enable" feels slightly >>>> wrong. And it probably should be "bluetooth" and not just "device" as >>>> this refers to a pin on a WiFi/BT combo chip. >>> >>> The Broadcom side called it shutdown GPIO, it is essentially the >>> shutdown/reset GPIO or power on/off GPIO. Personally I do not >>> care what it is named, but it will be all the same for all >>> Bluetooth chips. Take a poll from Broadcom, Intel, Realtek and >>> Qualcomm and you can pick a reasonable common name. >> >> The Nokia driver has "bluetooth-wakeup" gpio. The Broadcom one has >> "device-wakeup" and "shutdown". The "shutdown" gpio is set to its active >> state to power on the chip which sounds reversed logic. Same for the >> "bt-disable-n" gpio in the Qualcomm driver, configured as ACTIVE_HIGH, and >> which is set to 1 to enable it... >> >> So for consistency, naming it as "shutdown" to stick to the bcm driver but >> it should be configured as ACTIVE_LOW in the dts so we actually do a >> gpiod_set_value(0) to un-shutdown it. Does that sound ok? > > FWIW you picked the wrong gpio from the nokia bluetooth binding. The > gpio for shutdown would be "reset". The "bluetooth-wakeup" is > required for normal operation to exit idle mode. The "reset" name > used by the nokia binding is quite common for DT: > > Documentation/devicetree/bindings $ git grep reset-gpios | wc -l > 212 > > I guess it only makes sense when the device is actually being > reset, though (i.e. for Nokia the settings are back to defaults > and you need to re-upload the FW). that is actually a good point. I like to differentiate between a shutdown GPIO (and we can argue about the inversion here) and the reset GPIO. If we loose the firmware and the programmed BD_ADDR, then it is a hard-reset, otherwise it is shutdown/power GPIO. So can we agree on how we name the hard-reset, shutdown, wakeup etc. GPIOs for Bluetooth UART devices? Regards Marcel -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
