i2c: mxs: remove broken PIOQUEUE support
This I2C master can do DMA and PIOQUEUE (PIO with FIFO). Originally, only PIOQUEUE was supported and it had issues, then DMA support was added this cycle. The original intention was to keep PIOQUEUE since it has less overhead what is nice for small transfers. However, runtime switching between PIOQEUE and DMA depending on the transfer size never worked despite a lot of trying. Since PIOQUEUE mode itself was flaky (polling at places where interrupts failed to work) and the implementation also imposed a size limit for transfers, it is best to remove the support, so users don't fall over its limitations. It also makes the driver a lot cleaner and more robust. If somebody really wants less overhead, plain PIO mode could still be implemented with the addidtional advantage that this mode is also available on MX23, too. Signed-off-by: Wolfram Sang <w.sang@pengutronix.de> Reviewed-by: Marek Vasut <marex@denx.de>
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