gpio: core: support HW PWM on gpiochip outputs

firmware/controllers/algo/obd_error_codes.h

@@ -2168,4 +2168,8 @@ enum class ObdCode : uint16_t {
 	 * Commanded fuel exceeds your fuel injector flow
 	 */
 	CUSTOM_TOO_LONG_FUEL_INJECTION = 9013,
+	/**
+	 * GPIO chip errors
+	 */
+	CUSTOM_GPIO_CHIP_FAILED_PWM = 9014,
 };

firmware/hw_layer/drivers/gpio/core.cpp

@@ -28,7 +28,7 @@
 /* Local variables and types.												*/
 /*==========================================================================*/
 
-/* TODO: chnage array to list? */
+/* TODO: change array to list? */
 struct gpiochip {
 	brain_pin_e			base;
 	size_t				size;
@@ -40,6 +40,47 @@ struct gpiochip {
 
 static gpiochip chips[BOARD_EXT_GPIOCHIPS];
 
+/* TODO: move inside gpio chip driver? */
+class external_hardware_pwm : public hardware_pwm {
+public:
+	bool hasInit() const {
+		return m_chip != nullptr;
+	}
+
+	int start(const char* msg, gpiochip* chip, size_t pin, float frequency, float duty) {
+		int ret;
+
+		ret = chip->chip->setPadPWM(pin, frequency, duty);
+		if (ret >= 0) {
+			m_chip = chip;
+			m_pin = pin;
+			m_frequency = frequency;
+		} else {
+			/* This is not an error, will fallback to SW PWM */
+			//firmwareError(ObdCode::CUSTOM_GPIO_CHIP_FAILED_PWM, "Faield to enable PWM mode for chip %s on pin \"%s\"", msg, chip->name, pin);
+			return -1;
+		}
+		return 0;
+	}
+
+	void setDuty(float duty) override {
+		if (!m_chip) {
+			criticalError("Attempted to set duty on null external PWM device");
+			return;
+		}
+
+		m_chip->chip->setPadPWM(m_pin, m_frequency, duty);
+	}
+
+private:
+	gpiochip* m_chip = nullptr;
+	size_t m_pin = 0;
+	float m_frequency = 0;
+};
+
+/* TODO: is 5 enought? */
+static external_hardware_pwm extPwms[5];
+
 /*==========================================================================*/
 /* Local functions.															*/
 /*==========================================================================*/
@@ -59,6 +100,17 @@ static gpiochip *gpiochip_find(brain_pin_e pin)
 	return nullptr;
 }
 
+static external_hardware_pwm* gpiochip_getNextPwmDevice() {
+	for (size_t i = 0; i < efi::size(extPwms); i++) {
+		if (!extPwms[i].hasInit()) {
+			return &extPwms[i];
+		}
+	}
+
+	criticalError("Run out of gpiochip PWM devices!");
+	return nullptr;
+}
+
 /*==========================================================================*/
 /* Exported functions.														*/
 /*==========================================================================*/
@@ -276,8 +328,8 @@ int gpiochips_writePad(brain_pin_e pin, int value) {
 	gpiochip *chip = gpiochip_find(pin);
 
 	if (!chip) {
-  // todo: make readPad fail in a similar way?
-	  criticalError("gpiochip not found for pin %d", pin);
+		// todo: make readPad fail in a similar way?
+		criticalError("gpiochip not found for pin %d", pin);
 		return -108;
 	}
 
@@ -302,6 +354,33 @@ int gpiochips_readPad(brain_pin_e pin)
 	return chip->chip->readPad(pin - chip->base);
 }
 
+/**
+ * @brief Try to init PWM on given pin
+ * @details success of call depends on chip capabilities
+ * returns nullptr in case there is no chip for given pin
+ * returns nullptr in case of pin is not PWM capable
+ * returns nullptr in case all extPwms are already used
+ * returns hardware_pwm if succes, later user can call ->setDuty to change duty
+ */
+
+hardware_pwm* gpiochip_tryInitPwm(const char* msg, brain_pin_e pin, float frequency, float duty)
+{
+	gpiochip *chip = gpiochip_find(pin);
+
+	if (!chip) {
+		return nullptr;
+	}
+
+	/* TODO: implement reintialization of same pin with different settings reusing same external_hardware_pwm */
+	if (external_hardware_pwm *device = gpiochip_getNextPwmDevice()) {
+		if (device->start(msg, chip, pin - chip->base, frequency, duty) >= 0) {
+			return device;
+		}
+	}
+
+	return nullptr;
+}
+
 /**
  * @brief Get diagnostic for given gpio
  * @details actual output value depend on gpiochip capabilities

firmware/hw_layer/drivers/gpio/gpio_ext.h

@@ -27,6 +27,7 @@ struct GpioChip {
 	virtual int setPadMode(size_t /*pin*/, iomode_t /*mode*/) { return -1; }
 	virtual int writePad(size_t /*pin*/, int /*value*/) { return -1; }
 	virtual int readPad(size_t /*pin*/) { return -1; }
+	virtual int setPadPWM(size_t /*pin*/, float /*frequency*/, float /*duty*/) { return -1; }
 	virtual brain_pin_diag_e getDiag(size_t /*pin*/) { return PIN_OK; }
 	virtual int deinit() { return 0; }
 
@@ -54,6 +55,7 @@ int gpiochips_init(void);
 int gpiochips_setPadMode(brain_pin_e pin, iomode_t mode);
 int gpiochips_writePad(brain_pin_e pin, int value);
 int gpiochips_readPad(brain_pin_e pin);
+hardware_pwm* gpiochip_tryInitPwm(const char* msg, brain_pin_e pin, float frequency, float duty);
 brain_pin_diag_e gpiochips_getDiag(brain_pin_e pin);
 
 /* return total number of external gpios */