• Wolfram Sang's avatar
    i2c: mxs: remove broken PIOQUEUE support · 82fa63bd
    Wolfram Sang authored
    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: default avatarWolfram Sang <w.sang@pengutronix.de>
    Reviewed-by: default avatarMarek Vasut <marex@denx.de>
    82fa63bd
i2c-mxs.c 14.2 KB