can: m_can: m_can_fifo_{read,write}: don't read or write from/to FIFO if length is 0
In order to optimize FIFO access, especially on m_can cores attached to slow busses like SPI, in patch | e3938177 ("can: m_can: Disable IRQs on FIFO bus errors") bulk read/write support has been added to the m_can_fifo_{read,write} functions. That change leads to the tcan driver to call regmap_bulk_{read,write}() with a length of 0 (for CAN frames with 0 data length). regmap treats this as an error: | tcan4x5x spi1.0 tcan4x5x0: FIFO write returned -22 This patch fixes the problem by not calling the cdev->ops->{read,write)_fifo() in case of a 0 length read/write. Fixes: e3938177 ("can: m_can: Disable IRQs on FIFO bus errors") Link: https://lore.kernel.org/all/20220114155751.2651888-1-mkl@pengutronix.de Cc: stable@vger.kernel.org Cc: Matt Kline <matt@bitbashing.io> Cc: Chandrasekar Ramakrishnan <rcsekar@samsung.com> Reported-by:Michael Anochin <anochin@photo-meter.com> Signed-off-by:
Marc Kleine-Budde <mkl@pengutronix.de>
parent
17a30422
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