Write a GPIO driver for ESP32

[zephyrbot]

Reported by Leandro Pereira:

Write a GPIO driver for ESP32.

(Imported from Jira ZEP-2286)

[zephyrbot]

by Leandro Pereira:

Got most of the driver written today; will likely post the code up for review tomorrow after testing and confirming it works as expected.

[zephyrbot]

by Leandro Pereira:

The driver is working for outputs; however, I can't get interrupts to work when attached to the GPIO interrupt source: an exception is thrown while trying to execute the ISR:
{code}*** Unhandled exception ****
Exception cause 28 (load prohibited):
EPC1 : 0x40080f5a EXCSAVE1 : 0x00040021 EXCVADDR : 0x00000054
Program state (PS):
INTLEVEL : 03 EXCM : 0 UM : 1 RING : 0 WOE : 1
OWB : 01 CALLINC : 2
Current thread ID = 0x3ffb1eb0
Faulting instruction address = 0xdeaddead
Fatal fault in ISR! Spinning...{code}

It's the same exception that happens when using IRQ offloading, so I think they're related. I know that the ISR is in the IRAM region, so in theory it should work. Will investigate more on Monday.

[zephyrbot]

by Leandro Pereira:

Spent some time on this driver today:

• The GPIO driver was refactored to use the pin mux driver.
• Exception 28 still happens right before calling the ISR. The difference is that the panic happens only when the pin is toggled, proving that setting the interrupt source is working properly now.

[zephyrbot]

by Leandro Pereira:

Found the culprit for the exception when calling the ISR, and the callback function is working as expected. Will clean everything up tomorrow and post it up for review.

[zephyrbot]

by Mark Linkmeyer:

Since Leandro is now on vacation I'm reassigning this to Andy Ross to finish driving it to the Merged state before the 1.9 Feature Merge Window closes next week. Thanks for the help Andy!

[zephyrbot]

by Chandrakala Kempanna:

Nirmala Devi M Please Verify the Story

[zephyrbot]

by Nirmala Devi M:

This story can be tested with $Zephyr_base/tests/drivers/gpio/gpio_basic_api. And code support for ESP32 for this story is merged in zephyr/master.

Tested and verified this story in master/1f46eb66.