11:47 <suniel> Hi everyone.

11:47 <suniel> I have a situation. I have a carrier board with wifi/bt chip on SDIO/UART.

11:47 <suniel> This wifi chip is driven by a 32KHz external oscillator. The power to thisoscillator is +3v3 from a regulator whose input is 5V.

11:47 <suniel> How to write device tree node to enable the oscillator ? so that it candrive the wifi/bt chip.

11:48 <suniel> this is my external clock node:

11:48 <suniel> xin32k: xin32k { compatible = "fixed-clock"; #clock-cells = <0>; clock-frequency = <32768>; clock-output-names = "xin32k"; };

11:58 <inode> have you got a power sequence provider node configured for it? (ie. compatible = "mmc-pwrseq-simple")

11:58 <robmur01> suniel: look up mmc-pwrseq - that's usually how those clocks are handled

12:01 <suniel> yes, i have that in place

12:01 <suniel> sdio_pwrseq: sdio-pwrseq { compatible = "mmc-pwrseq-simple"; clocks = <&xin32k>; clock-names = "ext_clock"; pinctrl-names = "default"; pinctrl-0 = <&wifi_enable_h>; reset-gpios = <&gpio1 RK_PC3 GPIO_ACTIVE_LOW>; status = "okay"; };

12:04 <suniel> what i understand is, that this external oscillator activates only with a 3.3v supply. how do i inform this fixed oscillator(xin32k) to use 3.3v ?

12:22 <robmur01> so it's really a standalone oscillator with its own switchable supply, not just an output from an RTC chip or some other component?

12:23 <robmur01> that's a little atypical, and I guess none of the existing bindings/drivers support it

12:24 <robmur01> short of adding regulator support to fixed-clock, I'd be tempted to just bodge the power tree such that the OS thinks that regulator is supplying some other device/regulator that does get claimed at an appropriate point

12:27 <inode> i'm going to bet it's an hym8563 hiding behind door number xin32k

12:33 <suniel> inode, hym8563 is not hiding

12:33 <suniel> its an external oscillator

12:40 <inode> isn't Vdd fixed then?

13:07 <suniel> yes i think so, vdd is fixed

13:13 <inode> sorry, didn't see your xin32k node snippet earlier

13:20 <inode> do you need the clock and pinctrl config in your pwrseq though? does your wifi_enable_h specify the same pin as reset-gpio?

13:21 <suniel> yes

13:22 <inode> which module are you using?

13:23 <suniel> its a Sterling-LWBTM 2.4 GHz Wi-Fi® and Bluetooth® SmartReady Multi-Standard Module.

13:24 <suniel> based on broadcom brcm4343w chipset

13:27 <inode> do you have a datasheet or at least the pin config for it?

13:29 <suniel> yes i have

13:29 <suniel> i have the board schematic on which this wifi/bt is installed

13:31 <inode> if that broadcom chip is anything like a realtek sdio module i have, there are two active low disable pins (wlan & bluetooth) that have both to be toggled to initialize the radio for wlan operation