Commit a9aaf1ff88a8 ("power: sequencing: request the WLAN enable GPIO
as-is") broke WLAN on boards on which the wlan-enable GPIO enabling the
wifi module isn't in output mode by default. We need to set direction to
output while retaining the value that was already set to keep the ath
module on if it's already started.

Fixes: a9aaf1ff88a8 ("power: sequencing: request the WLAN enable GPIO as-is")
Link: https://lore.kernel.org/r/20240823115500.37280-1-brgl@bgdev.pl
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

If the WCN module is powered up before linux boots and the ath11k driver
probes at the same time as the power sequencing driver, we may end up
driving the wlan-enable GPIO low in the latter, breaking the start-up of
the WLAN module. Request the wlan-enable GPIO as-is so that if the WLAN
module is already starting/started, we leave it alone.

Fixes: 2f1630f437df ("power: pwrseq: add a driver for the PMU module on the QCom WCN chipsets")
Reported-by: Stephan Gerhold <stephan.gerhold@linaro.org>
Link: https://lore.kernel.org/r/20240813190751.155035-1-brgl@bgdev.pl
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

We may end up calling pwrseq_target_free() on a partially initialized
target object whose unit is either NULL or an ERR_PTR(). Avoid
dereferencing invalid memory by adding an appropriate check to
pwrseq_target_free().

Fixes: 249ebf3f65f8 ("power: sequencing: implement the pwrseq core")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/linux-pm/62a3531e-9927-40f8-b587-254a2dfa47ef@stanley.mountain/
Reviewed-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/20240712194004.241939-1-brgl@bgdev.pl
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Use 'return_ptr' helper for returning a pointer without cleanup for
shorter code.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240703083038.95777-1-krzysztof.kozlowski@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

This adds the power sequencing driver for the PMU modules present on the
Qualcomm WCN Bluetooth and Wifi chipsets. It uses the pwrseq subsystem
and knows how to match the sequencer to the consumer device by verifying
the relevant properties and DT layout. Using this driver will allow the
BT and WLAN drivers to respect the required delays between enabling the
two modules.

Tested-by: Amit Pundir <amit.pundir@linaro.org>
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8550-QRD, SM8650-QRD & SM8650-HDK
Tested-by: Caleb Connolly <caleb.connolly@linaro.org> # OnePlus 8T
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240605123850.24857-3-brgl@bgdev.pl
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Implement the power sequencing subsystem allowing devices to share
complex powering-up and down procedures. It's split into the consumer
and provider parts but does not implement any new DT bindings so that
the actual power sequencing is never revealed in the DT representation.

Tested-by: Amit Pundir <amit.pundir@linaro.org>
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8550-QRD, SM8650-QRD & SM8650-HDK
Tested-by: Caleb Connolly <caleb.connolly@linaro.org> # OnePlus 8T
Acked-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20240605123850.24857-2-brgl@bgdev.pl
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>