76 lines
1.8 KiB
Go
76 lines
1.8 KiB
Go
package edison
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import "strconv"
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// pwmPath returns pwm base path
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func pwmPath() string {
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return "/sys/class/pwm/pwmchip0"
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}
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// pwmExportPath returns export path
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func pwmExportPath() string {
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return pwmPath() + "/export"
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}
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// pwmUnExportPath returns unexport path
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func pwmUnExportPath() string {
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return pwmPath() + "/unexport"
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}
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// pwmDutyCyclePath returns duty_cycle path for specified pin
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func pwmDutyCyclePath(pin string) string {
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return pwmPath() + "/pwm" + pin + "/duty_cycle"
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}
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// pwmPeriodPath returns period path for specified pin
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func pwmPeriodPath(pin string) string {
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return pwmPath() + "/pwm" + pin + "/period"
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}
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// pwmEnablePath returns enable path for specified pin
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func pwmEnablePath(pin string) string {
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return pwmPath() + "/pwm" + pin + "/enable"
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}
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type pwmPin struct {
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pin string
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}
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// newPwmPin returns an exported and enabled pwmPin
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func newPwmPin(pin int) *pwmPin {
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return &pwmPin{pin: strconv.Itoa(pin)}
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}
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// enable writes value to pwm enable path
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func (p *pwmPin) enable(val string) (err error) {
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_, err = writeFile(pwmEnablePath(p.pin), []byte(val))
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return
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}
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// period reads from pwm period path and returns value
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func (p *pwmPin) period() (period string, err error) {
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buf, err := readFile(pwmPeriodPath(p.pin))
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if err != nil {
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return
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}
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return string(buf[0 : len(buf)-1]), nil
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}
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// writeDuty writes value to pwm duty cycle path
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func (p *pwmPin) writeDuty(duty string) (err error) {
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_, err = writeFile(pwmDutyCyclePath(p.pin), []byte(duty))
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return
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}
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// export writes pin to pwm export path
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func (p *pwmPin) export() (err error) {
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_, err = writeFile(pwmExportPath(), []byte(p.pin))
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return
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}
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// export writes pin to pwm unexport path
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func (p *pwmPin) unexport() (err error) {
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_, err = writeFile(pwmUnExportPath(), []byte(p.pin))
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return
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}
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