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11da3403e9
For nearly all commands in U-Boot the '?' variable is handled the same way with 0 meaning success, 1 meaning any failure. Explain this in the general rules section of the cmdline documentation (with a link to a counter example) and then remove the redundant wording from most commands. We retain a section about the return value in a number of places where we are doing something such as always returning a specific value or we have useful additional information to go along with the normal return codes. Signed-off-by: Tom Rini <trini@konsulko.com> Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
86 lines
1.5 KiB
ReStructuredText
86 lines
1.5 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0-or-later
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.. index::
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single: pwm (command)
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pwm command
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===========
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Synopsis
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--------
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::
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pwm invert <pwm_dev_num> <channel> <polarity>
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pwm config <pwm_dev_num> <channel> <period_ns> <duty_ns>
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pwm enable <pwm_dev_num> <channel>
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pwm disable <pwm_dev_num> <channel>
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Description
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-----------
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The ``pwm`` command is used to access and configure PWM (Pulse Width Modulation)
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signals.
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pwm invert
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----------
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* If the value of ``polarity`` is 0, the default polarity is used.
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* If the value of ``polarity`` is 1, the polarity is inverted.
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pwm config
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----------
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Configure the period and duty period in nanoseconds.
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pwm enable
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----------
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Enable output on the configured device and channel.
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pwm disable
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-----------
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Disable output on the configured device and channel.
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pwm_dev_num
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Device number of the pulse width modulation device
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channel
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Output channel of the PWM device
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polarity
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* 0 - Use normal polarity
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* 1 - Use inverted polarity
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duty_ns
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Duty period in ns
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period_ns
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Period time in ns
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Examples
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--------
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Configure device 0, channel 0 to 20 µs period and 14 µs (that is, 70%) duty period::
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=> pwm config 0 0 20000 14000
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Enable output on the configured device and channel::
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=> pwm enable 0 0
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Disable output on the configured device and channel::
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=> pwm disable 0 0
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Invert the signal on the configured device and channel::
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=> pwm invert 0 0 1
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Configuration
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-------------
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The ``pwm`` command is only available if CONFIG_CMD_PWM=y.
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