pinctrl help - no way to set ALT0 function (doc or indexing issue)
drankinatty opened this issue · 3 comments
pinctrl help (as of commit 6dc6f5f) lists the valid options for set as:
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Valid [options] for pinctrl set are:
ip set GPIO as input
op set GPIO as output
a1-a7 set GPIO to fsel in the range 1-7
no set GPIO to no function (NONE)
pu set GPIO in-pad pull up
pd set GPIO pin-pad pull down
pn set GPIO pull none (no pull)
dh set GPIO to drive high (1) level (only valid if set to be an output)
dl set GPIO to drive low (0) level (only valid if set to be an output)
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However, the valid ALTx functions on the Pi are indexed 0-5. I have not been through the code to determine if this is simply a documentation issue or an indexing issue, but on first impression there is no way to set the a0 function for any pin. Displaying current get information discloses the a0 functions in use on many pins, e.g.
$ pinctrl get 7-11
7: op -- -- | hi // SPI_CE1_N/GPIO7 = output
8: op -- -- | hi // SPI_CE0_N/GPIO8 = output
9: a0 -- | lo // SPI_MISO/GPIO9 = SPI0_MISO
10: a0 -- | lo // SPI_MOSI/GPIO10 = SPI0_MOSI
11: a0 -- | lo // SPI_SCLK/GPIO11 = SPI0_SCLK
If there is no valid a0 option for pinctrl, just how does one go about restoring an a0 function?
Conversely, raspi-gpio help lists the set options with the 0-5 ALT functions available, e.g.
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Valid [options] for raspi-gpio set are:
ip set GPIO as input
op set GPIO as output
a0-a5 set GPIO to alternate function alt0-alt5
pu set GPIO in-pad pull up
pd set GPIO pin-pad pull down
pn set GPIO pull none (no pull)
dh set GPIO to drive to high (1) level (only valid if set to be an output)
dl set GPIO to drive low (0) level (only valid if set to be an output)
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Seems a quick check on what pinctrl does for a0 is in order. This is a great little set of utilities!
The help text is wrong - values a0 to a8 are recognised, but not valid on all platforms.
Thank you. pinctrl is a great little tool!