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From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Subject: [PATCH RFC 0/7] usb: typec: ucsi: rework glue driver interface
Date: Mon, 03 Jun 2024 02:24:53 +0300
Message-Id: <20240603-ucsi-rework-interface-v1-0-99a6d544cec8@linaro.org>
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To: Heikki Krogerus <heikki.krogerus@linux.intel.com>, 
 Greg Kroah-Hartman <gregkh@linuxfoundation.org>, 
 Maxime Coquelin <mcoquelin.stm32@gmail.com>, 
 Alexandre Torgue <alexandre.torgue@foss.st.com>
Cc: Nikita Travkin <nikita@trvn.ru>, 
 Neil Armstrong <neil.armstrong@linaro.org>, linux-usb@vger.kernel.org, 
 linux-kernel@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, 
 linux-arm-kernel@lists.infradead.org

The interface between UCSI and the glue driver is very low-level. It
allows reading the UCSI data from any offset (but in reality the UCSI
driver reads only VERSION, CCI an MESSAGE_IN data). All event handling
is to be done by the glue driver (which already resulted in several
similar-but-slightly different implementations). It leaves no place to
optimize the write-read-read sequence for the command execution (which
might be beneficial for some of the drivers), etc.

The patchseries attempts to restructure the UCSI glue driver interface
in order to provide sensible operations instead of a low-level read /
write calls.

If this approach is found to be acceptable, I plan to further rework the
command interface, moving reading CCI and MESSAGE_IN to the common
control code, which should simplify driver's implementation and remove
necessity to split quirks between sync_control and read_message_in e.g.
as implemented in the ucsi_ccg.c.

Note, the series was tested only on the ucsi_glink platforms. Further
testing is appreciated.

Depends: [1], [2]

[1] https://lore.kernel.org/linux-usb/20240521151109.3078775-1-fabrice.gasnier@foss.st.com/

[2] https://lore.kernel.org/linux-usb/20240531104653.1303519-1-heikki.krogerus@linux.intel.com/

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
Dmitry Baryshkov (7):
      usb: typec: ucsi: move ucsi_acknowledge() from ucsi_read_error()
      usb: typec: ucsi: simplify command sending API
      usb: typec: ucsi: split read operation
      usb: typec: ucsi: rework command execution functions
      usb: typec: ucsi: inline ucsi_read_message_in
      usb: typec: ucsi: extract common code for command handling
      usb: typec: ucsi: reorder operations in ucsi_run_command()

 drivers/usb/typec/ucsi/ucsi.c         | 215 ++++++++++++++++++----------------
 drivers/usb/typec/ucsi/ucsi.h         |  26 ++--
 drivers/usb/typec/ucsi/ucsi_acpi.c    | 100 ++++++++--------
 drivers/usb/typec/ucsi/ucsi_ccg.c     | 103 +++++++---------
 drivers/usb/typec/ucsi/ucsi_glink.c   |  74 ++++--------
 drivers/usb/typec/ucsi/ucsi_stm32g0.c |  79 +++++--------
 6 files changed, 277 insertions(+), 320 deletions(-)
---
base-commit: 975aa2136eebb8c7c716ac2d24d9bfdb002f87fd
change-id: 20240525-ucsi-rework-interface-5ff2264f6aec

Best regards,
-- 
Dmitry Baryshkov <dmitry.baryshkov@linaro.org>