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[ Upstream commit 70e633bedeeb4a7290d3b1dd9d49cc2bae25a46f ]
When the driver is removed, the clocks are first enabled by
calling pm_runtime_get_sync(), and then disabled with
pm_runtime_put_sync().
If CONFIG_PM=y, clocks for this controller are disabled when it's in
the idle state. So the clocks are properly disabled when the driver
exits.
Othewise, the clocks are always enabled and the PM functions have
no effect. Therefore, the driver exits without disabling the clocks.
# cat /sys/kernel/debug/clk/clk-pclk/clk_enable_count
18
# echo 1214a000.i2c > /sys/bus/platform/drivers/i2c_designware/bind
# cat /sys/kernel/debug/clk/clk-pclk/clk_enable_count
20
# echo 1214a000.i2c > /sys/bus/platform/drivers/i2c_designware/unbind
# cat /sys/kernel/debug/clk/clk-pclk/clk_enable_count
20
To ensure that the clocks can be disabled correctly even without
CONFIG_PM=y, should add the following fixes:
- Replace with pm_runtime_put_noidle(), which only decrements the runtime
PM usage count.
- Call i2c_dw_prepare_clk(false) to explicitly disable the clocks.
Fixes: 7272194ed3 ("i2c-designware: add minimal support for runtime PM")
Co-developed-by: Kohei Ito <ito.kohei@socionext.com>
Signed-off-by: Kohei Ito <ito.kohei@socionext.com>
Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
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https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.