STM32L4 serial PM interface improvements * stm32l4_serial: pm: check rx/tx buffers for pending data in pmprepare * stm32l4: remove adhoc PM interfaces and move serial suspend functionality behind CONFIG_PM Approved-by: Gregory Nutt <gnutt@nuttx.org>
STM32L4 serial PM interface improvements * stm32l4_serial: pm: check rx/tx buffers for pending data in pmprepare * stm32l4: remove adhoc PM interfaces and move serial suspend functionality behind CONFIG_PM Approved-by: Gregory Nutt <gnutt@nuttx.org>