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Subject: [PATCH v6 0/1] i2c: Restore power status of device if probe fails
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From:   Ricardo Ribalda <ribalda@chromium.org>
Date:   Mon, 14 Nov 2022 13:20:33 +0100
Message-Id: <20221109-i2c-waive-v6-0-bc059fb7e8fa@chromium.org>
To:     "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
        Tomasz Figa <tfiga@chromium.org>,
        Mika Westerberg <mika.westerberg@linux.intel.com>,
        Wolfram Sang <wsa@kernel.org>
Cc:     Hidenori Kobayashi <hidenorik@chromium.org>,
        stable@vger.kernel.org,
        Sergey Senozhatsky <senozhatsky@chromium.org>,
        linux-kernel@vger.kernel.org,
        Hidenori Kobayashi <hidenorik@google.com>,
        Sakari Ailus <sakari.ailus@linux.intel.com>,
        Ricardo Ribalda <ribalda@chromium.org>,
        linux-i2c@vger.kernel.org
Precedence: bulk

We have discovered that some power lines were always on even if the devices
on that power line was not used.

This happens because we failed to probe a device on the i2c bus, and the
ACPI Power Resource were never turned off.

This patch tries to fix this issue.

To: Mika Westerberg <mika.westerberg@linux.intel.com>
To: Wolfram Sang <wsa@kernel.org>
To: Sakari Ailus <sakari.ailus@linux.intel.com>
To: Tomasz Figa <tfiga@chromium.org>
To: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Cc: Hidenori Kobayashi <hidenorik@google.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: linux-i2c@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
---
Changes in v6:
- Add Reviewed-by: Hidenori (Thanks!).
- Set device always off at remove.
- Link to v5: https://lore.kernel.org/r/20221109-i2c-waive-v5-0-2839667f8f6a@chromium.org

Changes in v5:
- Add Cc: stable
- Add Reviewed-by Sakary (Thanks!).
- Renamed turn-off as power-off, in the name of consistency (Thanks Sergey!)
- Link to v4: https://lore.kernel.org/r/20221109-i2c-waive-v4-0-e4496462833b@chromium.org

Changes in v4:
- Rename full_power to do_power_on.
- Link to v3: https://lore.kernel.org/r/20221109-i2c-waive-v3-0-d8651cb4b88d@chromium.org

Changes in v3:
- Introduce full_power variable to make more clear what we are doing.
- Link to v2: https://lore.kernel.org/r/20221109-i2c-waive-v2-0-07550bf2dacc@chromium.org

Changes in v2:
- Cover also device remove
- Link to v1: https://lore.kernel.org/r/20221109-i2c-waive-v1-0-ed70a99b990d@chromium.org

---
Ricardo Ribalda (1):
      i2c: Restore initial power state if probe fails

 drivers/i2c/i2c-core-base.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)
---
base-commit: f141df371335645ce29a87d9683a3f79fba7fd67
change-id: 20221109-i2c-waive-ae97fea1f1b5

Best regards,
-- 
Ricardo Ribalda <ribalda@chromium.org>