Add required changes for zmk power domain support #8
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Add API to add devices to a power domain in runtime. The number of devices that can be added is defined in build time. The script gen_handles.py will check the number defined in `CONFIG_PM_DEVICE_POWER_DOMAIN_DYNAMIC` to resize the handles vector, adding empty slots in the supported sector to be used later. Signed-off-by: Flavio Ceolin <[email protected]>
…ation as the parent
Removed configure lines
Added log to pd_gpio_pm_action
When a power domain is connected to another power domain,`pd_gpio_init` attempts to configure the gpio pin to `GPIO_DISCONNECTED`. But if that failed, the init function returned -EIO, which caused the device to be marked as not initialized / ready. This meant that it couldn’t be retrieved through `device_get_binding()`.
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area: I2C
area: API
area: Kernel
area: Power Management
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Hey guys, these are the necessary changes to add power domain support in ZMK.
Please review it in conjunction with the zmk PR: zmkfirmware/zmk#1300
Background Info
To be completely honest... I don't full understand many of the decisions behind zephyr's original code.
For example...
PM_DEVICE_ACTION_TURN_ONsets the device state toPM_DEVICE_STATE_SUSPENDEDI am not sure why, I would have expected it to set it to
PM_DEVICE_STATE_ACTIVE.Because of this, in the zmk code, I use
PM_DEVICE_ACTION_RESUMEin zmk's code to enable power domains.You can find it here:
https://github.com/infused-kim/zmk-zephyr/blob/v3.0.0%2Bzmk-fixes%2Bpd-oled/subsys/pm/device.c#L140-L146
pd_gpio_pm_actionforwards different actions to childrenAnother thing that seems off is that
pd_gpio_pm_actionforwards different actions to it's children.For example:
PM_DEVICE_ACTION_RESUMErunsPM_DEVICE_ACTION_TURN_ONon the childrenPM_DEVICE_ACTION_SUSPENDrunsPM_DEVICE_ACTION_TURN_OFFon the childrenPM_DEVICE_ACTION_TURN_ONruns nothing on the childrenPM_DEVICE_ACTION_TURN_OFFruns nothing on the childrenI have modified it to always run the matching action to the children.
https://github.com/zmkfirmware/zephyr/blob/v3.0.0%2Bzmk-fixes/drivers/power_domain/power_domain_gpio.c#L48
pd_gpio_pm_actiononly toggled GPIO pin forRESUMEandSUSPENDactionsFor example:
PM_DEVICE_ACTION_RESUMEset the pin to 1PM_DEVICE_ACTION_SUSPENDset the pin 0PM_DEVICE_ACTION_TURN_ONdid NOT set the pin to 1, but instead configured it toGPIO_OUTPUT_INACTIVEPM_DEVICE_ACTION_TURN_OFFdid NOT set the pin to 0, but instead configured it toGPIO_DISCONNECTEDTo be completely honest, I have no idea what it means for the pin to be configured to
GPIO_OUTPUT_INACTIVEandGPIO_DISCONNECTED.So I just changed the actions to turn and off the pins instead of configuring them.
https://github.com/zmkfirmware/zephyr/blob/v3.0.0%2Bzmk-fixes/drivers/power_domain/power_domain_gpio.c#L59
pd_gpio_initcould fail ifgpio_pin_configure_dtfailedThis is another issue I ran into when adding a power domain as a child to another power domain.
For reference:
https://github.com/zmkfirmware/zephyr/blob/v3.0.0%2Bzmk-fixes/drivers/power_domain/power_domain_gpio.c#L84-L88
If a power domain is a child of another power domain, then the code attempts to configure the pin as
GPIO_DISCONNECTED.If that fails, the init function returns a non 0 return code.
That in turn causes the device to be marked as not initialized.
When attempting to get the device through
device_get_binding(), it fails and prevents zmk code to not work properly.So I changed this by ignoring the return code of
gpio_pin_configure_dtand to always return 0.In conclusion...
I have made it work, but I don't fully understand the original intentions of the zephyr developers.
Maybe these were bugs and I fixed them or maybe I just don't understand how power domains are supposed to work and made wrong assumptions.
I would really appreciate it if you could guide me to the right solution if what I did is not correct.
Thank you.