samples: boards: firmware for Twinkie V2

sample firmware for Twinkie V2 that toggles the LED based on charging
status.

Signed-off-by: Jason Yuan <jasonyuan@google.com>

boards/arm/google_twinkie_v2/board.cmake

@@ -1,13 +1,9 @@
 # SPDX-License-Identifier: Apache-2.0
 
 board_runner_args(dfu-util "--pid=0483:df11" "--alt=0" "--dfuse")
-
-include(${ZEPHYR_BASE}/boards/common/dfu-util.board.cmake)
-
 board_runner_args(stm32cubeprogrammer "--port=swd" "--reset=hw")
-
-include(${ZEPHYR_BASE}/boards/common/stm32cubeprogrammer.board.cmake)
-
 board_runner_args(jlink "--device=STM32G0B1RE" "--speed=4000")
 
+include(${ZEPHYR_BASE}/boards/common/dfu-util.board.cmake)
+include(${ZEPHYR_BASE}/boards/common/stm32cubeprogrammer.board.cmake)
 include(${ZEPHYR_BASE}/boards/common/jlink.board.cmake)

boards/arm/google_twinkie_v2/doc/index.rst

@@ -9,8 +9,6 @@ Overview
 Google Twinkie V2 is a reference board for the google power delivery analyzer
 (PDA) Twinkie V2.
 
-Zephyr has support for the STM32-based embedded controller (EC) on-board.
-
 Hardware
 ********
 

boards/arm/google_twinkie_v2/google_twinkie_v2.dts

@@ -32,6 +32,10 @@
 
  gpio_keys {
  compatible = "gpio-keys";
+
+ /* does not go to an actual button in current hardware.
+ * short TP5 to TP6 to activate.
+ */
  dfu_detect: dfudetect {
  gpios = <&gpioa 14 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
  };
@@ -70,11 +74,7 @@
  sense-gain-mult = <25>;
  };
 
-
  aliases {
- led0 = &red_led_0;
- led1 = &green_led_1;
- led2 = &blue_led_2;
  bootloader-led0 = &blue_led_2;
  vcc1 = &cc1_buf;
  vcc2 = &cc2_buf;
@@ -84,7 +84,6 @@
  };
 };
 
-
 &adc1 {
  #address-cells = <1>;
  #size-cells = <0>;
@@ -96,6 +95,9 @@
  &adc1_in18_pc5 /* CSA_CC2 */
  >;
 
+ pinctrl-names = "default";
+ status = "okay";
+
  channel@1 {
  reg = <1>;
  zephyr,gain = "ADC_GAIN_1";
@@ -140,9 +142,6 @@
  zephyr,acquisition-time = <ADC_ACQ_TIME_DEFAULT>;
  zephyr,resolution = <12>;
  };
-
- pinctrl-names = "default";
- status = "okay";
 };
 
 &clk_hsi {
@@ -175,6 +174,6 @@
 
  psc-ucpdclk = <1>;
  hbitclkdiv = <27>;
- pinctrl-names = "default";
  pinctrl-0 = <&ucpd1_cc1_pa8 &ucpd1_cc2_pb15>;
+ pinctrl-names = "default";
 };

samples/boards/google_twinkie_v2_pda/CMakeLists.txt

@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(google_twinkie_v2)
+
+FILE(GLOB app_sources src/*.c)
+target_sources(app PRIVATE ${app_sources})

samples/boards/google_twinkie_v2_pda/README.rst

@@ -0,0 +1,25 @@
+.. _google_twinkie_v2_pda:
+
+Twinkie Power Delivery
+######################
+
+Overview
+********
+
+This provides access to :ref:`Twinkie <google_twinkie_v2_board>` so you can try out
+the supported features.
+
+Building and Running
+********************
+
+Build and flash Twinkie as follows:
+
+.. zephyr-app-commands::
+ :zephyr-app: samples/boards/google_pda
+ :board: google_twinkie_v2
+ :goals: build flash
+ :compact:
+
+After flashing, the LED will start red. Putting the Twinkie in between any
+usbc connection will cause the LED to turn blue. The LED will turn green instead
+if the device is currently charging.

samples/boards/google_twinkie_v2_pda/prj.conf

@@ -0,0 +1,4 @@
+CONFIG_ADC=y
+CONFIG_ADC_STM32=y
+CONFIG_GPIO=y
+CONFIG_LED=y

samples/boards/google_twinkie_v2_pda/sample.yaml

@@ -0,0 +1,6 @@
+sample:
+ name: Twinkie V2 usb Vbus snooper
+tests:
+ sample.board.google_twinkie_v2:
+ platform_allow: google_twinkie_v2
+ tags: usb

samples/boards/google_twinkie_v2_pda/src/meas.c

@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) 2023 The ChromiumOS Authors
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <stdio.h>
+#include <zephyr/kernel.h>
+#include <zephyr/drivers/adc.h>
+#include <zephyr/drivers/adc/voltage_divider.h>
+#include <zephyr/drivers/adc/current_sense_amplifier.h>
+
+/* The devicetree node identifier for the adc aliases. */
+#define VBUS_V_MEAS_NODE DT_ALIAS(vbus)
+#define VBUS_C_MEAS_NODE DT_ALIAS(cbus)
+
+static const struct voltage_divider_dt_spec adc_vbus_v =
+ VOLTAGE_DIVIDER_DT_SPEC_GET(VBUS_V_MEAS_NODE);
+static const struct current_sense_amplifier_dt_spec adc_vbus_c =
+ CURRENT_SENSE_AMPLIFIER_DT_SPEC_GET(VBUS_C_MEAS_NODE);
+
+int meas_vbus_v(int32_t *v)
+{
+ int ret;
+ int32_t sample_buffer = 0;
+
+ /* Structure defining an ADC sampling sequence */
+ struct adc_sequence sequence = {
+ .buffer = &sample_buffer,
+ /* buffer size in bytes, not number of samples */
+ .buffer_size = sizeof(sample_buffer),
+ .calibrate = true,
+ };
+ adc_sequence_init_dt(&adc_vbus_v.port, &sequence);
+
+ ret = adc_read(adc_vbus_v.port.dev, &sequence);
+ if (ret != 0) {
+ return ret;
+ }
+
+ *v = sample_buffer;
+ ret = adc_raw_to_millivolts_dt(&adc_vbus_v.port, v);
+ if (ret != 0) {
+ return ret;
+ }
+
+ ret = voltage_divider_scale_dt(&adc_vbus_v, v);
+ if (ret != 0) {
+ return ret;
+ }
+
+ return 0;
+}
+
+int meas_vbus_c(int32_t *c)
+{
+ int ret;
+ int32_t sample_buffer = 0;
+
+ /* Structure defining an ADC sampling sequence */
+ struct adc_sequence sequence = {
+ .buffer = &sample_buffer,
+ /* buffer size in bytes, not number of samples */
+ .buffer_size = sizeof(sample_buffer),
+ .calibrate = true,
+ };
+ adc_sequence_init_dt(&adc_vbus_c.port, &sequence);
+
+ ret = adc_read(adc_vbus_c.port.dev, &sequence);
+ if (ret != 0) {
+ return ret;
+ }
+
+ *c = sample_buffer;
+ ret = adc_raw_to_millivolts_dt(&adc_vbus_c.port, c);
+ if (ret != 0) {
+ return ret;
+ }
+
+ /* prescaling the voltage offset */
+ *c -= adc_vbus_c.port.vref_mv / 2;
+ current_sense_amplifier_scale_dt(&adc_vbus_c, c);
+
+ return 0;
+}
+
+int meas_init(void)
+{
+ int ret;
+
+ ret = adc_channel_setup_dt(&adc_vbus_v.port);
+ if (ret != 0) {
+ return ret;
+ }
+
+ ret = adc_channel_setup_dt(&adc_vbus_c.port);
+ if (ret != 0) {
+ return ret;
+ }
+
+ return 0;
+}

samples/boards/google_twinkie_v2_pda/src/meas.h

@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2023 The ChromiumOS Authors
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef __MEAS_H__
+#define __MEAS_H__
+
+/**
+ * @brief Initializes the measurement module, sets up all the adc channels through the device tree
+ * binding
+ *
+ * @return 0 on success
+ */
+int meas_init(void);
+
+/**
+ * @brief Measure the voltage on VBUS
+ *
+ * @param v pointer where VBUS voltage, in millivolts, is stored
+ *
+ * @return 0 on success
+ */
+int meas_vbus_v(int32_t *v);
+
+/**
+ * @brief Measure the current on VBUS
+ *
+ * @param c pointer where VBUS current, in milliamperes, is stored
+ *
+ * @return 0 on success
+ */
+int meas_vbus_c(int32_t *c);
+
+#endif

samples/boards/google_twinkie_v2_pda/src/view.c

@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2023 The ChromiumOS Authors
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/device.h>
+#include <zephyr/drivers/led.h>
+#include <zephyr/kernel.h>
+
+#include "meas.h"
+
+enum led_color_t {
+ LED_RED,
+ LED_GREEN,
+ LED_BLUE,
+};
+
+static void set_led(const struct device *const led, enum led_color_t led_color)
+{
+ if (led_color != LED_RED) led_off(led, LED_RED);
+ if (led_color != LED_GREEN) led_off(led, LED_GREEN);
+ if (led_color != LED_BLUE) led_off(led, LED_BLUE);
+ led_on(led, led_color);
+}
+
+#define CHARGING_VOLTAGE 5000
+#define CHARGING_CURRENT 1000
+
+void main(void)
+{
+ meas_init();
+
+ const struct device *const led = DEVICE_DT_GET_ONE(gpio_leds);
+ int32_t vbus_v = 0;
+ int32_t vbus_c = 0;
+
+ if (!device_is_ready(led)) {
+ return;
+ }
+
+ while (1) {
+ meas_vbus_v(&vbus_v);
+ meas_vbus_c(&vbus_c);
+
+ if (vbus_v > CHARGING_VOLTAGE) {
+ if (vbus_c > CHARGING_CURRENT) {
+ set_led(led, LED_GREEN);
+ } else {
+ set_led(led, LED_BLUE);
+ }
+ } else {
+ set_led(led, LED_RED);
+ }
+
+ k_usleep(500);
+ }
+}