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Add open-drain GPIO support. #15282

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merged 6 commits into from
Dec 27, 2021
Merged

Add open-drain GPIO support. #15282

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0c6a4c8
Add open-drain GPIO support.
tzarc Nov 23, 2021
8defc7b
`qmk format-c`
tzarc Nov 23, 2021
2aa121b
Wording.
tzarc Nov 23, 2021
bc81f52
Merge remote-tracking branch 'upstream/develop' into open-drain-outputs
tzarc Nov 28, 2021
cb6e057
Merge remote-tracking branch 'upstream/develop' into open-drain-outputs
tzarc Dec 9, 2021
d33a2d1
Remove port GPIO implementations as the only board that uses it has i…
tzarc Dec 9, 2021
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Wording.
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@tzarc
tzarc committed Nov 23, 2021
commit 2aa121b443dd746684f05a8f3b6b099c75b77d38
2 changes: 1 addition & 1 deletion docs/internals_gpio_control.md
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Expand Up @@ -13,7 +13,7 @@ The following functions provide basic control of GPIOs and are found in `platfor
| `setPinInputLow(pin)` | Set pin as input with builtin pull-down resistor | N/A (Not supported on AVR) | `palSetLineMode(pin, PAL_MODE_INPUT_PULLDOWN)` |
| `setPinOutput(pin)` | Set pin as output (alias of `setPinOutputPushPull`) | `DDRB \|= (1<<2)` | `palSetLineMode(pin, PAL_MODE_OUTPUT_PUSHPULL)` |
| `setPinOutputPushPull(pin)` | Set pin as output, push/pull mode | `DDRB \|= (1<<2)` | `palSetLineMode(pin, PAL_MODE_OUTPUT_PUSHPULL)` |
| `setPinOutputOpenDrain(pin)` | Set pin as output, open-drain mode | N/A (Not supported on AVR) | `palSetLineMode(pin, PAL_MODE_OUTPUT_OPENDRAIN)` |
| `setPinOutputOpenDrain(pin)` | Set pin as output, open-drain mode | N/A (Not implemented on AVR) | `palSetLineMode(pin, PAL_MODE_OUTPUT_OPENDRAIN)` |
| `writePinHigh(pin)` | Set pin level as high, assuming it is an output | `PORTB \|= (1<<2)` | `palSetLine(pin)` |
| `writePinLow(pin)` | Set pin level as low, assuming it is an output | `PORTB &= ~(1<<2)` | `palClearLine(pin)` |
| `writePin(pin, level)` | Set pin level, assuming it is an output | `(level) ? PORTB \|= (1<<2) : PORTB &= ~(1<<2)` | `(level) ? palSetLine(pin) : palClearLine(pin)` |
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2 changes: 1 addition & 1 deletion platforms/arm_atsam/gpio.h
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Expand Up @@ -54,7 +54,7 @@ typedef uint8_t pin_t;
PORT->Group[SAMD_PORT(pin)].OUTCLR.reg = SAMD_PIN_MASK(pin); \
} while (0)

#define setPinOutputOpenDrain(pin) _Static_assert(0, "arm_atsam HAL does not yet implement an open-drain output")
#define setPinOutputOpenDrain(pin) _Static_assert(0, "arm_atsam platform does not implement an open-drain output")

#define setPinOutput(pin) setPinOutputPushPull(pin)

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4 changes: 2 additions & 2 deletions platforms/avr/gpio.h
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Expand Up @@ -26,7 +26,7 @@ typedef uint8_t pin_t;
#define setPinInputHigh(pin) (DDRx_ADDRESS(pin) &= ~_BV((pin)&0xF), PORTx_ADDRESS(pin) |= _BV((pin)&0xF))
#define setPinInputLow(pin) _Static_assert(0, "AVR processors cannot implement an input as pull low")
#define setPinOutputPushPull(pin) (DDRx_ADDRESS(pin) |= _BV((pin)&0xF))
#define setPinOutputOpenDrain(pin) _Static_assert(0, "AVR processors cannot implement an open-drain output")
#define setPinOutputOpenDrain(pin) _Static_assert(0, "AVR platform does not implement an open-drain output")
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Technically it is possible to implement an open-drain output on AVR — set the PORTx bit to 0, then write the inverted output value to the DDRx bit. The problem is that it requires either some conditional code in the writePin() implementation, or a separate set of macros like writeOpenDrainPin(), writeOpenDrainPinHigh(), writeOpenDrainPinLow() (with bad consequences if you use a wrong kind of macro for the chosen pin mode).

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Yep, but nobody has asked for it, and nobody's using it. Figured it'd be a problem for another day.

#define setPinOutput(pin) setPinOutputPushPull(pin)

#define writePinHigh(pin) (PORTx_ADDRESS(pin) |= _BV((pin)&0xF))
Expand All @@ -46,7 +46,7 @@ typedef uint8_t port_data_t;
#define setPortBitInput(port, bit) (DDRx_ADDRESS(port) &= ~_BV((bit)&0xF), PORTx_ADDRESS(port) &= ~_BV((bit)&0xF))
#define setPortBitInputHigh(port, bit) (DDRx_ADDRESS(port) &= ~_BV((bit)&0xF), PORTx_ADDRESS(port) |= _BV((bit)&0xF))
#define setPortBitOutputPushPull(port, bit) (DDRx_ADDRESS(port) |= _BV((bit)&0xF))
#define setPortBitOutputOpenDrain(port, bit) _Static_assert(0, "AVR processors cannot implement an open-drain output")
#define setPortBitOutputOpenDrain(port, bit) _Static_assert(0, "AVR platform does not implement an open-drain output")
#define setPortBitOutput(port, bit) setPortBitOutputPushPull((port), (bit))

#define writePortBitLow(port, bit) (PORTx_ADDRESS(port) &= ~_BV((bit)&0xF))
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