boards: arm: Introduce Google Dragonclaw Development Board

# Copyright (c) 2022 Google LLC

# SPDX-License-Identifier: Apache-2.0

config BOARD_GOOGLE_DRAGONCLAW

	bool "Google Dragonclaw Development Board"

	depends on SOC_STM32F412CX

# Copyright (c) 2022 Google LLC

# SPDX-License-Identifier: Apache-2.0

if BOARD_GOOGLE_DRAGONCLAW

config BOARD

	default "google_dragonclaw"

endif # BOARD_GOOGLE_DRAGONCLAW

# Copyright (c) 2022 Google LLC

# SPDX-License-Identifier: Apache-2.0

board_runner_args(jlink "--device=STM32F412CG" "--speed=4000")

include(${ZEPHYR_BASE}/boards/common/openocd.board.cmake)

include(${ZEPHYR_BASE}/boards/common/jlink.board.cmake)

.. _google_dragonclaw_board:

Google Dragonclaw Development Board

###################################

Overview

********

Dragonclaw is a board created by Google for fingerprint-related functionality

development. See the `Dragonclaw Schematics`_ for board schematics, layout and

BOM.

Board has connectors for fingerprint sensors. Console is exposed over μServo

connector. MCU can be flashed using μServo or SWD.

Hardware

********

- STM32F412CGU6 UFQFPN48 package

Peripherial Mapping

===================

- USART_1 TX/RX : PA9/PA10

- USART_2 TX/RX : PA2/PA3

- SPI_1 CS/CLK/MISO/MOSI : PA4/PA5/PA6/PA7

- SPI_2 CS/CLK/MISO/MOSI : PB12/PB13/PB14/PB15

Programming and Debugging

*************************

Build application as usual for the ``dragonclaw`` board, and flash

using μServo or an external J-Link connected to J4. If μServo is used, please

follow the `Chromium EC Flashing Documentation`_.

Debugging

=========

Use SWD with a J-Link or ST-Link. Remember that SW2 must be set to CORESIGHT.

References

**********

.. target-notes::

.. _Dragonclaw Schematics:

   https://chromium.googlesource.com/chromiumos/platform/ec/+/HEAD/docs/schematics/dragonclaw

.. _Chromium EC Flashing Documentation:

   https://chromium.googlesource.com/chromiumos/platform/ec#Flashing-via-the-servo-debug-board

/*

 * Copyright (c) 2022 Google LLC

 *

 * SPDX-License-Identifier: Apache-2.0

 */

/dts-v1/;

#include <st/f4/stm32f412Xg.dtsi>

#include <st/f4/stm32f412z(e-g)tx-pinctrl.dtsi>

/ {

	model = "Google Dragonclaw development board";

	compatible = "google,dragonclaw-fpmcu";

	chosen {

		zephyr,console = &usart2;

		zephyr,shell-uart = &usart2;

		zephyr,sram = &sram0;

		zephyr,flash = &flash0;

		zephyr,flash-controller = &flash;

	};

};

&clk_hsi {

	/* HSI clock frequency is 16MHz */

	status = "okay";

};

&clk_lsi {

	/* LSI clock frequency is 32768kHz */

	status = "okay";

};

&pll {

	div-m = <8>;

	mul-n = <192>; /* 16MHz * 192/8 = 384MHz VCO clock */

	div-p = <4>; /* 96MHz PLL general clock output */

	div-q = <8>; /* 48MHz PLL output for USB, SDIO, RNG */

	clocks = <&clk_hsi>;

	status = "okay";

};

&rcc {

	clocks = <&pll>; /* Select PLL as SYSCLK source (96MHz) */

	ahb-prescaler = <1>; /* SYSCLK not divided */

	clock-frequency = <DT_FREQ_M(96)>; /* AHB frequency */

	apb1-prescaler = <2>; /* AHB clock divided by 2 */

	apb2-prescaler = <2>; /* AHB clock divided by 2 */

};

/* USART1: AP UART (Host Commands and MKBP) */

&usart1 {

	pinctrl-0 = <&usart1_tx_pa9 &usart1_rx_pa10>;

	pinctrl-names = "default";

	current-speed = <115200>;

	status = "okay";

};

/* USART2: Servo UART (console) */

&usart2 {

	pinctrl-0 = <&usart2_tx_pa2 &usart2_rx_pa3>;

	pinctrl-names = "default";

	current-speed = <115200>;

	status = "okay";

};

/* SPI1: communication with the AP */

&spi1 {

	pinctrl-0 = <&spi1_nss_pa4 &spi1_sck_pa5

		     &spi1_miso_pa6 &spi1_mosi_pa7>;

	pinctrl-names = "default";

	status = "okay";

};

/* SPI2: communication with the fingerprint sensor */

&spi2 {

	pinctrl-0 = <&spi2_nss_pb12 &spi2_sck_pb13

		     &spi2_miso_pb14 &spi2_mosi_pb15>;

	pinctrl-names = "default";

	status = "okay";

};

&rtc {

	clocks = <&rcc STM32_CLOCK_BUS_APB1 0x10000000>,

		 <&rcc STM32_SRC_LSI RTC_SEL(2)>;

	status = "okay";

	backup_regs {

		status = "okay";

	};

};

/*

 * The board uses STM32F412CG in UFQFPN48 package in which gpio[c-h] is not

 * exposed, so disable it.

 */

&gpioc {status = "disabled";};

&gpiod {status = "disabled";};

&gpioe {status = "disabled";};

&gpiof {status = "disabled";};

&gpiog {status = "disabled";};

&gpioh {status = "disabled";};