bindings: Documentation: Add document for wcnss node

* Qualcomm Technologies Inc. WCNSS Platform Driver

WCNSS driver is the platform driver. It is used for performing the cold

boot-up of the wireless device. It is responsible for adjusting

the necessary I/O rails and enabling appropriate gpios for wireless

connectivity subsystem.

Required properties:

- compatible: "wcnss_wlan"

- reg: physical address and length of the register set for the device.

- reg-names: "wcnss_mmio", "wcnss_fiq", "pronto_phy_base", "riva_phy_base",

	"riva_ccu_base", "pronto_a2xb_base", "pronto_ccpu_base",

	"pronto_saw2_base", "wlan_tx_phy_aborts","wlan_brdg_err_source",

	"wlan_tx_status", "alarms_txctl", "alarms_tactl",

	"pronto_mcu_base", "pronto_qfuse".

- interupts: Pronto to Apps interrupts for tx done and rx pending.

- qcom,pronto-vddmx-supply: regulator to supply pronto pll.

- qcom,pronto-vddcx-supply: voltage corner regulator to supply WLAN/BT/FM

digital module.

- qcom,pronto-vddpx-supply: regulator to supply WLAN DAC.

- qcom,iris-vddxo-supply  : regulator to supply RF XO.

- qcom,iris-vddrfa-supply : regulator to supply RFA digital.

- qcom,iris-vddpa-supply  : regulator to supply RF PA.

- qcom,iris-vdddig-supply : regulator to supply RF digital(BT/FM).

- gpios: gpio numbers to configure 5-wire interface of WLAN connectivity

- qcom,has-48mhz-xo: boolean flag to determine the usage of 24MHz XO from RF

- qcom,has-pronto-hw: boolean flag to determine the revId of the WLAN subsystem

- qcom,wcnss-adc_tm: ADC handle for vbatt notification APIs.

- qcom,wcnss-vadc: VADC handle for battery voltage notification APIs.

- pinctrl-<n> : Pinctrl states as described in bindings/pinctrl/pinctrl-bindings.txt

- pinctrl-names : Names corresponding to the numbered pinctrl states

- clocks: from common clock binding: handle to xo, rf_clk and wcnss snoc clocks.

- clock-names: Names of all the clocks that are accessed by the subsystem

- qcom,vdd-voltage-level: This property represents (nominal, min, max) voltage

for iris and pronto regulators in milli-volts.

- qcom,vdd-current: This property represents current value for

iris and pronto regulators in micro-amps.

Optional properties:

- qcom,has-autodetect-xo: boolean flag to determine whether Iris XO auto detect

should be performed during boot up.

- qcom,snoc-wcnss-clock-freq: indicates the wcnss snoc clock frequency in Hz.

If wcnss_snoc clock is specified in the list of clocks, this property needs

to be set to make it functional.

- qcom,wlan-rx-buff-count: WLAN RX buffer count is a configurable value,

using a smaller count for this buffer will reduce the memory usage.

- qcom,is-pronto-v3: boolean flag to determine the pronto hardware version

in use. subsequently correct workqueue will be used by DXE engine to push frames

in TX data path.

- qcom,is-dual-band-disable: boolean flag to determine the WLAN dual band

capability.

- qcom,is-pronto-vadc: boolean flag to determine Battery voltage feature

support for pronto hardware.

- qcom,wcnss-pm : <Core rail LDO#, PA rail LDO#, XO settling time,

RPM power collapse enabled, standalone power collapse enabled>

Power manager related parameter for LDO configuration.

	11     -  WCN CORE rail LDO number

	21     -  WCN PA rail LDO number

	1200   -  WCN XO settling time (usec)

	1      -  WCN RPM power collapse enabled

	1      -  WCN standalone power collapse enabled

	6      -  GPIO strength value

- qcom,has-vsys-adc-channel: boolean flag to determine which ADC HW channel need

to use for VBATT feature.

- qcom,has-a2xb-split-reg: boolean flag to determine A2xb split timeout limit

register is available or not.

Example:

qcom,wcnss-wlan@fb000000 {

	compatible = "qcom,wcnss_wlan";

	reg = <0xfb000000 0x280000>,

	    <0xf9011008 0x04>;

reg-names = "wcnss_mmio", "wcnss_fiq";

	interrupts = <0 145 0 0 146 0>;

	interrupt-names = "wcnss_wlantx_irq", "wcnss_wlanrx_irq";

	qcom,pronto-vddmx-supply = <&pm8841_s1>;

	qcom,pronto-vddcx-supply = <&pm8841_s2_corner>;

	qcom,pronto-vddpx-supply = <&pm8941_s3>;

	qcom,iris-vddxo-supply = <&pm8941_l6>;

	qcom,iris-vddrfa-supply = <&pm8941_l11>;

	qcom,iris-vddpa-supply = <&pm8941_l19>;

	qcom,iris-vdddig-supply = <&pm8941_l3>;

	gpios = <&msmgpio 36 0>, <&msmgpio 37 0>, <&msmgpio 38 0>,

	      <&msmgpio 39 0>, <&msmgpio 40 0>;

	qcom,has-48mhz-xo;

	qcom,is-pronto-vt;

	qcom,wlan-rx-buff-count = <512>;

	qcom,has-pronto-hw;

	qcom,wcnss-adc_tm = <&pm8226_adc_tm>;

	pinctrl-names = "wcnss_default", "wcnss_sleep";

	pinctrl-0 = <&wcnss_default>;

	pinctrl-1 = <&wcnss_sleep>;

	pinctrl-2 = <&wcnss_gpio_default>;

	clocks = <&clock_rpm clk_xo_wlan_clk>,

	       <&clock_rpm clk_rf_clk2>,

	       <&clock_debug clk_gcc_debug_mux>,

	       <&clock_gcc clk_wcnss_m_clk>,

	       <&clock_gcc clk_snoc_wcnss_a_clk>;

	clock-names = "xo", "rf_clk", "measure", "wcnss_debug",

		"snoc_wcnss";

	qcom,snoc-wcnss-clock-freq = <200000000>;

	qcom,wcnss-pm = <11 21 1200 1 1 6>;

};