Use slightly flatter directory structure since some developers did not

like too many folders.
Extracted code from some files into separate files to fit with the new
layout.

src/drivers/pwm_common.h

@@ -0,0 +1,51 @@
+#pragma once
+
+#define MAX_MOTORS  12
+#define MAX_SERVOS  8
+#define MAX_INPUTS  8
+#define PULSE_1MS       (1000) // 1ms pulse width
+
+typedef struct drv_pwm_config_t {
+    bool enableInput;
+    bool usePPM;
+    bool useUART;
+    bool useSoftSerial;
+    bool useServos;
+    bool extraServos;    // configure additional 4 channels in PPM mode as servos, not motors
+    bool airplane;       // fixed wing hardware config, lots of servos etc
+    uint8_t adcChannel;  // steal one RC input for current sensor
+    uint16_t motorPwmRate;
+    uint16_t servoPwmRate;
+    uint16_t idlePulse;  // PWM value to use when initializing the driver. set this to either PULSE_1MS (regular pwm), 
+                         // some higher value (used by 3d mode), or 0, for brushed pwm drivers.
+    uint16_t servoCenterPulse;
+    uint16_t failsafeThreshold;
+} drv_pwm_config_t;
+
+// This indexes into the read-only hardware definition structure in drv_pwm.c, as well as into pwmPorts[] structure with dynamic data.
+enum {
+    PWM1 = 0,
+    PWM2,
+    PWM3,
+    PWM4,
+    PWM5,
+    PWM6,
+    PWM7,
+    PWM8,
+    PWM9,
+    PWM10,
+    PWM11,
+    PWM12,
+    PWM13,
+    PWM14,
+    MAX_PORTS
+};
+
+void pwmICConfig(TIM_TypeDef *tim, uint8_t channel, uint16_t polarity);
+
+bool pwmInit(drv_pwm_config_t *init); // returns whether driver is asking to calibrate throttle or not
+void pwmWriteMotor(uint8_t index, uint16_t value);
+void pwmWriteServo(uint8_t index, uint16_t value);
+uint16_t pwmRead(uint8_t channel);
+
+// void pwmWrite(uint8_t channel, uint16_t value);