linux-kernel - [PATCH v1 0/3] I3C mastership handover support

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Message-ID: <1586211645-8065-1-git-send-email-pthombar@cadence.com>
Date:   Tue, 7 Apr 2020 00:20:45 +0200
From:   Parshuram Thombare <pthombar@...ence.com>
To:     <bbrezillon@...nel.org>, <vitor.soares@...opsys.com>
CC:     <pgaj@...ence.com>, <linux-i3c@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <mparab@...ence.com>,
        Parshuram Thombare <pthombar@...ence.com>
Subject: [PATCH v1 0/3] I3C mastership handover support

Hi,

This patch series is to enable mastership handover feature in I3C
master subsystem and Cadence's I3C controller driver.

[PATCH 1/3]
i3c: master: split bus_init callback into bus_init and master_set_info
There are 2 reasons for this split
Currently bus_init callback is involved in
a. Controller specific settings such as clock prescalar, enabling
   different functionalities and finally enabling the controller.
b. Allocating address to the main master and calling 
   i3c_master_set_info, which basically create a I3C device for master
   and add it to system. This is fine for main master, but for
   secondary master this should be deferred until controller actually
   owns the bus/mastership.

Another reason is, to support secondary master initialization without
board info, controller specific bus mode setting need to be done twice
First with pure bus mode and second time when actual bus mode is known
based on data received through DEFSLVS, whereas master set info is
supposed to be done only once.

[PATCH 2/3]
i3c: add mastership handover support to i3c master subsystem
This patch add mastership handover support as per MIPI I3C
spec v1.0. Main master and secondary masters starts in pure
bus mode to allow enumeration (DAA) to happen in same bus mode.
Secondary masters are not required to have information about
other devices connected on the bus through board info, this
information is derived from DEFSLVS received from main
master. While acquiring mastership, requesting master always
make sure that it has active dynamic address, and received
DEFSLVS at least once. Mastership request state machine
make sure that any pending DEFSLVS is processed, so that
when device become master it always have correct view
of the bus.

[PATCH 3/3]
i3c: master: add mastership handover support to cdns i3c master driver
This patch adds mastership handover support to the Cadence
I3C controller driver. Basically, this include necessary
callbacks for mastership request.

Regards,
Parshuram Thombare

Parshuram Thombare (3):
  i3c: master: split bus_init callback into bus_init and master_set_info
  i3c: add mastership handover support to i3c master subsystem
  i3c: master: add mastership handover support to cdns i3c master driver

 drivers/i3c/master.c                 | 490 ++++++++++++++++++++++++---
 drivers/i3c/master/dw-i3c-master.c   |  29 +-
 drivers/i3c/master/i3c-master-cdns.c | 385 ++++++++++++++++++---
 include/linux/i3c/master.h           |  47 ++-
 4 files changed, 854 insertions(+), 97 deletions(-)

-- 
2.17.1