commit 048bbbdbf85e5e00258dfb12f5e368f908801d7b upstream.
In case there is any sort of clock controller attached to this I2C bus
controller, for example Versaclock or even an AIC32x4 I2C codec, then
an I2C transfer triggered from the clock controller clk_ops .prepare
callback may trigger a deadlock on drivers/clk/clk.c prepare_lock mutex.
This is because the clock controller first grabs the prepare_lock mutex
and then performs the prepare operation, including its I2C access. The
I2C access resumes this I2C bus controller via .runtime_resume callback,
which calls clk_prepare_enable(), which attempts to grab the prepare_lock
mutex again and deadlocks.
Since the clock are already prepared since probe() and unprepared in
remove(), use simple clk_enable()/clk_disable() calls to enable and
disable the clock on runtime suspend and resume, to avoid hitting the
prepare_lock mutex.
Acked-by: Alain Volmat <alain.volmat@foss.st.com>
Signed-off-by: Marek Vasut <marex@denx.de>
Fixes: 4e7bca6fc07b ("i2c: i2c-stm32f7: add PM Runtime support")
Cc: <stable@vger.kernel.org> # v5.0+
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c896ff2dd8f30a6b0a922c83a96f6d43f05f0e92 upstream.
In case of SMBUS byte read with PEC enabled, the whole transfer
is split into two commands. A first write command, followed by
a read command. The write command does not have any PEC byte
and a PEC byte is appended at the end of the read command.
(cf Read byte protocol with PEC in SMBUS specification)
Within the STM32 I2C controller, handling (either sending
or receiving) of the PEC byte is done via the PECBYTE bit in
register CR2.
Currently, the PECBYTE is set at the beginning of a transfer,
which lead to sending a PEC byte at the end of the write command
(hence losing the real last byte), and also does not check the
PEC byte received during the read command.
This patch corrects the function stm32f7_i2c_smbus_xfer_msg
in order to only set the PECBYTE during the read command.
Fixes: 9e48155f6bfe ("i2c: i2c-stm32f7: Add initial SMBus protocols support")
Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Reviewed-by: Pierre-Yves MORDRET <pierre-yves.mordret@foss.st.com>
Acked-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
