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00cc81f4e4
Add gpio status output fields description and one output example. Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com> Reviewed-by: Simon Glass <sjg@chromium.org> Tweak the formatting. Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
133 lines
2.6 KiB
ReStructuredText
133 lines
2.6 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0+:
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gpio command
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============
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Synopsis
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--------
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::
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gpio <input|set|clear|toggle> <pin>
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gpio read <name> <pin>
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gpio status [-a] [<bank>|<pin>]
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The gpio command is used to access General Purpose Inputs/Outputs.
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gpio input
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----------
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Switch the GPIO *pin* to input mode.
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gpio set
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--------
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Switch the GPIO *pin* to output mode and set the signal to 1.
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gpio clear
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----------
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Switch the GPIO *pin* to output mode and set the signal to 0.
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gpio toggle
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-----------
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Switch the GPIO *pin* to output mode and reverse the signal state.
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gpio read
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---------
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Read the signal state of the GPIO *pin* and save it in environment variable
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*name*.
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gpio status
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-----------
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Display the status of one or multiple GPIOs. By default only claimed GPIOs
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are displayed.
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gpio status command output fields are::
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<name>: <function>: <value> [x] <label>
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*function* can take the following values:
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output
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pin configured in gpio output, *value* indicates the pin's level
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input
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pin configured in gpio input, *value* indicates the pin's level
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func
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pin configured in alternate function, followed by *label*
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which shows pinmuxing label.
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unused
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pin not configured
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*[x]* or *[ ]* indicate respectively if the gpio is used or not.
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*label* shows the gpio label.
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Parameters
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----------
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-a
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Display GPIOs irrespective of being claimed.
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bank
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Name of a bank of GPIOs to be displayed.
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pin
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Name of a single GPIO to be displayed or manipulated.
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Examples
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--------
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Switch the status of a GPIO::
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=> gpio set a5
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gpio: pin a5 (gpio 133) value is 1
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=> gpio clear a5
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gpio: pin a5 (gpio 133) value is 0
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=> gpio toggle a5
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gpio: pin a5 (gpio 133) value is 1
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=> gpio read myvar a5
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gpio: pin a5 (gpio 133) value is 1
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=> echo $myvar
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1
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=> gpio toggle a5
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gpio: pin a5 (gpio 133) value is 0
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=> gpio read myvar a5
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gpio: pin a5 (gpio 133) value is 0
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=> echo $myvar
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0
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Show the GPIO status::
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=> gpio status
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Bank GPIOA:
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GPIOA1: func rgmii-0
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GPIOA2: func rgmii-0
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GPIOA7: func rgmii-0
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GPIOA10: output: 0 [x] hdmi-transmitter@39.reset-gpios
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GPIOA13: output: 1 [x] red.gpios
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Bank GPIOB:
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GPIOB0: func rgmii-0
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GPIOB1: func rgmii-0
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GPIOB2: func uart4-0
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GPIOB7: input: 0 [x] mmc@58005000.cd-gpios
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GPIOB11: func rgmii-0
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Configuration
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-------------
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The *gpio* command is only available if CONFIG_CMD_GPIO=y.
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The *gpio read* command is only available if CONFIG_CMD_GPIO_READ=y.
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Return value
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------------
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If the command succeds the return value $? is set to 0. If an error occurs, the
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return value $? is set to 1.
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