From 982ef08655d214191f798aafd7ac0531ffab1c03 Mon Sep 17 00:00:00 2001
From: Charlie Haley <charlie.haley@hotmail.com>
Date: Sun, 9 Jan 2022 20:23:48 +0000
Subject: [PATCH] rp2040: implement PWMGroup func to get peripheral from pin

---
 src/machine/machine.go            | 16 ++++++++++++++++
 src/machine/machine_rp2040_pwm.go | 31 +++++++++++++++++++++++--------
 2 files changed, 39 insertions(+), 8 deletions(-)

diff --git a/src/machine/machine.go b/src/machine/machine.go
index 06274220da..5fcdf3f8c0 100644
--- a/src/machine/machine.go
+++ b/src/machine/machine.go
@@ -53,3 +53,19 @@ func (p Pin) Low() {
 type ADC struct {
 	Pin Pin
 }
+
+type pwmer interface {
+	Configure(config PWMConfig) error
+	Channel(pin Pin) (uint8, error)
+	SetPeriod(period uint64) error
+	Top() uint32
+	Counter() uint32
+	Period() uint64
+	SetInverting(channel uint8, inverting bool)
+	Set(channel uint8, value uint32)
+	Get(channel uint8) uint32
+	SetTop(top uint32)
+	SetCounter(ctr uint32)
+	Enable(enable bool)
+	IsEnabled() bool
+}
diff --git a/src/machine/machine_rp2040_pwm.go b/src/machine/machine_rp2040_pwm.go
index a355be4c8b..2160c9601d 100644
--- a/src/machine/machine_rp2040_pwm.go
+++ b/src/machine/machine_rp2040_pwm.go
@@ -45,8 +45,10 @@ type pwmGroup struct {
 }
 
 // Equivalent of
-//  var pwmSlice []pwmGroup = (*[8]pwmGroup)(unsafe.Pointer(rp.PWM))[:]
-//  return &pwmSlice[index]
+//
+//	var pwmSlice []pwmGroup = (*[8]pwmGroup)(unsafe.Pointer(rp.PWM))[:]
+//	return &pwmSlice[index]
+//
 // 0x14 is the size of a pwmGroup.
 func getPWMGroup(index uintptr) *pwmGroup {
 	return (*pwmGroup)(unsafe.Pointer(uintptr(unsafe.Pointer(rp.PWM)) + 0x14*index))
@@ -94,6 +96,16 @@ func (pwm *pwmGroup) Channel(pin Pin) (channel uint8, err error) {
 	return pwmGPIOToChannel(pin), nil
 }
 
+// PWMforPin returns the RP2040 PWM Group for the given pin. If the pin does
+// not belong to a PWM peripheral ErrInvalidOutputPin error is returned.
+func PWMforPin(pin Pin) (pwmer pwmer, err error) {
+	sliceNum, err := PWMPeripheral(pin)
+	if err != nil {
+		return nil, err
+	}
+	return getPWMGroup(uintptr(sliceNum)), nil
+}
+
 // Peripheral returns the RP2040 PWM peripheral which ranges from 0 to 7. Each
 // PWM peripheral has 2 channels, A and B which correspond to 0 and 1 in the program.
 // This number corresponds to the package's PWM0 throughout PWM7 handles
@@ -112,7 +124,7 @@ func (pwm *pwmGroup) peripheral() uint8 {
 // SetPeriod updates the period of this PWM peripheral in nanoseconds.
 // To set a particular frequency, use the following formula:
 //
-//     period = 1e9 / frequency
+//	period = 1e9 / frequency
 //
 // Where frequency is in hertz. If you use a period of 0, a period
 // that works well for LEDs will be picked.
@@ -167,7 +179,7 @@ func (p *pwmGroup) SetInverting(channel uint8, inverting bool) {
 // cycle, in other words the fraction of time the channel output is high (or low
 // when inverted). For example, to set it to a 25% duty cycle, use:
 //
-//     pwm.Set(channel, pwm.Top() / 4)
+//	pwm.Set(channel, pwm.Top() / 4)
 //
 // pwm.Set(channel, 0) will set the output to low and pwm.Set(channel,
 // pwm.Top()) will set the output to high, assuming the output isn't inverted.
@@ -238,14 +250,17 @@ func (pwm *pwmGroup) setPhaseCorrect(correct bool) {
 }
 
 // Takes any of the following:
-//  rp.PWM_CH0_CSR_DIVMODE_DIV, rp.PWM_CH0_CSR_DIVMODE_FALL,
-//  rp.PWM_CH0_CSR_DIVMODE_LEVEL, rp.PWM_CH0_CSR_DIVMODE_RISE
+//
+//	rp.PWM_CH0_CSR_DIVMODE_DIV, rp.PWM_CH0_CSR_DIVMODE_FALL,
+//	rp.PWM_CH0_CSR_DIVMODE_LEVEL, rp.PWM_CH0_CSR_DIVMODE_RISE
 func (pwm *pwmGroup) setDivMode(mode uint32) {
 	pwm.CSR.ReplaceBits(mode<<rp.PWM_CH0_CSR_DIVMODE_Pos, rp.PWM_CH0_CSR_DIVMODE_Msk, 0)
 }
 
 // setPeriod sets the pwm peripheral period (frequency). Calculates DIV_INT,DIV_FRAC and sets it from following equation:
-//  cycles = (TOP+1) * (CSRPHCorrect + 1) * (DIV_INT + DIV_FRAC/16)
+//
+//	cycles = (TOP+1) * (CSRPHCorrect + 1) * (DIV_INT + DIV_FRAC/16)
+//
 // where cycles is amount of clock cycles per PWM period.
 func (pwm *pwmGroup) setPeriod(period uint64) error {
 	// This period calculation algorithm consists of
@@ -303,7 +318,7 @@ func (pwm *pwmGroup) setPeriod(period uint64) error {
 // frac's (DIV_FRAC) default value on reset is 0. Max value for frac is 15 (4 bits). This is known as a fixed-point
 // fractional number.
 //
-//  cycles = (TOP+1) * (CSRPHCorrect + 1) * (DIV_INT + DIV_FRAC/16)
+//	cycles = (TOP+1) * (CSRPHCorrect + 1) * (DIV_INT + DIV_FRAC/16)
 func (pwm *pwmGroup) setClockDiv(Int, frac uint8) {
 	pwm.DIV.ReplaceBits((uint32(frac)<<rp.PWM_CH0_DIV_FRAC_Pos)|
 		u32max(uint32(Int), 1)<<rp.PWM_CH0_DIV_INT_Pos, rp.PWM_CH0_DIV_FRAC_Msk|rp.PWM_CH0_DIV_INT_Msk, 0)