X-Git-Url: https://git.ayoreis.com/Adafruit_Blinka-hackapet.git/blobdiff_plain/4957fd7530674c6bbdd6324c9340ff5a4e1fbbc6..6c48e5e4be302ba8a78c0d3f6bb614e933447f36:/src/adafruit_blinka/microcontroller/rockchip/PWMOut.py diff --git a/src/adafruit_blinka/microcontroller/rockchip/PWMOut.py b/src/adafruit_blinka/microcontroller/rockchip/PWMOut.py index ae0f0ae..1e5d6e4 100644 --- a/src/adafruit_blinka/microcontroller/rockchip/PWMOut.py +++ b/src/adafruit_blinka/microcontroller/rockchip/PWMOut.py @@ -1,3 +1,12 @@ +# SPDX-FileCopyrightText: 2021 Melissa LeBlanc-Williams for Adafruit Industries +# +# SPDX-License-Identifier: MIT +""" +Much code from https://github.com/vsergeev/python-periphery/blob/master/periphery/pwm.py +Copyright (c) 2015-2016 vsergeev / Ivan (Vanya) A. Sergeev +License: MIT +""" + import os from time import sleep from errno import EACCES @@ -8,12 +17,18 @@ except ImportError: raise RuntimeError("No PWM outputs defined for this board.") from ImportError +# pylint: disable=unnecessary-pass, too-many-instance-attributes + + class PWMError(IOError): """Base class for PWM errors.""" pass +# pylint: enable=unnecessary-pass + + class PWMOut: """Pulse Width Modulation Output Class""" @@ -23,20 +38,9 @@ class PWMOut: PWM_STAT_DELAY = 0.1 # Sysfs paths - _sysfs_path = "/sys/class/pwm" _chip_path = "pwmchip{}" _channel_path = "pwm{}" - # Sysfs commands - _export = "export" - _unexport = "unexport" - - # Pin commands - _pin_period = "period" - _pin_duty_cycle = "duty_cycle" - _pin_polarity = "polarity" - _pin_enable = "enable" - def __init__(self, pwm, *, frequency=500, duty_cycle=0, variable_frequency=False): """Instantiate a PWM object and open the sysfs PWM corresponding to the specified chip and channel. @@ -74,25 +78,30 @@ class PWMOut: self._chip = pwmout[0][0] self._channel = pwmout[0][1] - self._pwm = pwm - self._chip_path = os.path.join( - self._sysfs_path, self._chip_path.format(self._chip) + "/sys/class/pwm", self._chip_path.format(self._chip) ) self._channel_path = os.path.join( self._chip_path, self._channel_path.format(self._channel) ) + if variable_frequency: + print("Variable Frequency is not supported, continuing without it...") + if not os.path.isdir(self._chip_path): raise LookupError("Opening PWM: PWM chip {} not found.".format(self._chip)) if not os.path.isdir(self._channel_path): # Exporting the PWM. try: - with open(os.path.join(self._chip_path, self._export), "w") as f_export: + with open( + os.path.join(self._chip_path, "export"), "w", encoding="utf-8" + ) as f_export: f_export.write("{:d}\n".format(self._channel)) except IOError as e: - raise PWMError(e.errno, "Exporting PWM channel: " + e.strerror) + raise PWMError( + e.errno, "Exporting PWM channel: " + e.strerror + ) from IOError # Loop until PWM is exported exported = False @@ -118,6 +127,7 @@ class PWMOut: with open( os.path.join(self._channel_path, "period"), "w", + encoding="utf-8", ): break except IOError as e: @@ -132,6 +142,8 @@ class PWMOut: self.frequency = frequency self.duty_cycle = duty_cycle + self.polarity = "normal" + self.enable() # Cache the period for fast duty cycle updates self._period_ns = self._get_period_ns() @@ -142,32 +154,36 @@ class PWMOut: # Unexporting the PWM channel try: unexport_fd = os.open( - os.path.join(self._chip_path, self._unexport), os.O_WRONLY + os.path.join(self._chip_path, "unexport"), os.O_WRONLY ) os.write(unexport_fd, "{:d}\n".format(self._channel).encode()) os.close(unexport_fd) except OSError as e: - raise PWMError(e.errno, "Unexporting PWM: " + e.strerror) + raise PWMError(e.errno, "Unexporting PWM: " + e.strerror) from OSError self._chip = None self._channel = None def _write_channel_attr(self, attr, value): - with open(os.path.join(self._channel_path, attr), "w") as f_attr: + with open( + os.path.join(self._channel_path, attr), "w", encoding="utf-8" + ) as f_attr: f_attr.write(value + "\n") def _read_channel_attr(self, attr): - with open(os.path.join(self._channel_path, attr), "r") as f_attr: + with open( + os.path.join(self._channel_path, attr), "r", encoding="utf-8" + ) as f_attr: return f_attr.read().strip() # Methods def enable(self): - """Enable the PWM outout.""" + """Enable the PWM output.""" self.enabled = True def disable(self): - """Diable the PWM output.""" + """Disable the PWM output.""" self.enabled = False # Mutable properties @@ -183,11 +199,11 @@ class PWMOut: period = property(_get_period, _set_period) """Get or set the PWM's output period in seconds. - + Raises: PWMError: if an I/O or OS error occurs. TypeError: if value type is not int. - + :type: int, float """ @@ -201,11 +217,11 @@ class PWMOut: period_ms = property(_get_period_ms, _set_period_ms) """Get or set the PWM's output period in milliseconds. - + Raises: PWMError: if an I/O or OS error occurs. TypeError: if value type is not int. - + :type: int, float """ @@ -220,16 +236,16 @@ class PWMOut: period_us = property(_get_period_us, _set_period_us) """Get or set the PWM's output period in microseconds. - + Raises: PWMError: if an I/O or OS error occurs. TypeError: if value type is not int. - + :type: int """ def _get_period_ns(self): - period_ns = self._read_channel_attr(self._pin_period) + period_ns = self._read_channel_attr("period") try: period_ns = int(period_ns) except ValueError: @@ -252,11 +268,11 @@ class PWMOut: period_ns = property(_get_period_ns, _set_period_ns) """Get or set the PWM's output period in nanoseconds. - + Raises: PWMError: if an I/O or OS error occurs. TypeError: if value type is not int. - + :type: int """ @@ -268,7 +284,7 @@ class PWMOut: except ValueError: raise PWMError( None, 'Unknown duty cycle value: "{:s}"'.format(duty_cycle_ns_str) - ) + ) from ValueError return duty_cycle_ns @@ -280,11 +296,11 @@ class PWMOut: duty_cycle_ns = property(_get_duty_cycle_ns, _set_duty_cycle_ns) """Get or set the PWM's output duty cycle in nanoseconds. - + Raises: PWMError: if an I/O or OS error occurs. TypeError: if value type is not int. - + :type: int """ @@ -294,7 +310,8 @@ class PWMOut: def _set_duty_cycle(self, duty_cycle): if not isinstance(duty_cycle, (int, float)): raise TypeError("Invalid duty cycle type, should be int or float.") - elif not 0.0 <= duty_cycle <= 1.0: + + if not 0.0 <= duty_cycle <= 1.0: raise ValueError("Invalid duty cycle value, should be between 0.0 and 1.0.") # Convert duty cycle from ratio to nanoseconds @@ -332,7 +349,8 @@ class PWMOut: def _set_polarity(self, polarity): if not isinstance(polarity, str): raise TypeError("Invalid polarity type, should be str.") - elif polarity.lower() not in ["normal", "inversed"]: + + if polarity.lower() not in ["normal", "inversed"]: raise ValueError('Invalid polarity, can be: "normal" or "inversed".') self._write_channel_attr("polarity", polarity.lower()) @@ -351,7 +369,7 @@ class PWMOut: if enabled == "1": return True - elif enabled == "0": + if enabled == "0": return False raise PWMError(None, 'Unknown enabled value: "{:s}"'.format(enabled)) @@ -373,11 +391,14 @@ class PWMOut: # String representation def __str__(self): - return "PWM {:d}, chip {:d} (period={:f} sec, duty_cycle={:f}%, polarity={:s}, enabled={:s})".format( - self._channel, - self._chip, - self.period, - self.duty_cycle * 100, - self.polarity, - str(self.enabled), + return ( + "PWM {:d}, chip {:d} (period={:f} sec, duty_cycle={:f}%," + " polarity={:s}, enabled={:s})".format( + self._channel, + self._chip, + self.period, + self.duty_cycle * 100, + self.polarity, + str(self.enabled), + ) )