Among implemented STM32L4x5 devices, USART, GPIO and SYSCFG
have a clock source, but none has a corresponding test in QEMU.

This patch makes sure that all 3 devices create a clock correctly,
adds a QOM property to access clocks' periods from QTests,
and adds QTests checking that clock enable in RCC has the
expected results for all 3 devices.

Thank you for the reviews.

Changes from v3 to v4:
- removed 2nd commit (it was bumping up version id in
`vmstate_stm32l4x5_usart_base`, which is useless when not adding
any fields), it was a misunderstanding
- in `clock.c`, `vmstate_stm32l4x5_usart_base`, renamed `freq_hz` to
`period`
- in `clocks.rst`, specified that `qtest-clock-period` is only usable
from the QTests and not QEMU
- in `qtest/stm32l4x5.h`, used macros from "clock.h" to compute
the expected clock period in the right unit
- in `qtest/stm32l4x5.h`, removed "osdep.h" include

Changes from "v1" to v3:
- adding a commit to expose `qtest-clock-period`, a QOM property for
all clocks, only accessible from QTests, and mention it in clock.rst
- adapt QTests so that they use clock period instead of clock frequency
- remove `clock-freq-hz` QOM property in STM32L4x5 USART and SYSCFG
- dropping the commit migrating GPIO clocks as it's already upstream

Changes from v1 to an unfortunate second "v1":
- upgrading `VMStateDescription` to version 2 to account for
`VMSTATE_CLOCK()`
- QTests : consolidating `get_clock_freq_hz()` in a header
and making appropriate changes in stm32l4x5q_*-test.c

Signed-off-by: Inès Varhol <ines.varhol@telecom-paris.fr>

Inès Varhol (3):
  hw/misc: Create STM32L4x5 SYSCFG clock
  hw/clock: Expose 'qtest-clock-period' QOM property for QTests
  tests/qtest: Check STM32L4x5 clock connections

 docs/devel/clocks.rst               |  6 +++++
 include/hw/misc/stm32l4x5_syscfg.h  |  1 +
 tests/qtest/stm32l4x5.h             | 42 +++++++++++++++++++++++++++++
 hw/arm/stm32l4x5_soc.c              |  2 ++
 hw/core/clock.c                     | 16 +++++++++++
 hw/misc/stm32l4x5_syscfg.c          | 19 +++++++++++--
 tests/qtest/stm32l4x5_gpio-test.c   | 23 ++++++++++++++++
 tests/qtest/stm32l4x5_syscfg-test.c | 20 ++++++++++++--
 tests/qtest/stm32l4x5_usart-test.c  | 26 ++++++++++++++++++
 9 files changed, 151 insertions(+), 4 deletions(-)
 create mode 100644 tests/qtest/stm32l4x5.h

-- 
2.43.2