• Stefan Agner's avatar
    pwm: fsl-ftm: Use flat regmap cache · ad06fdee
    Stefan Agner authored
    Use flat regmap cache to avoid lockdep warning at probe:
    [    0.697285] WARNING: CPU: 0 PID: 1 at kernel/locking/lockdep.c:2755 lockdep_trace_alloc+0x15c/0x160()
    [    0.697449] DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))
    The RB-tree regmap cache needs to allocate new space on first writes.
    However, allocations in an atomic context (e.g. when a spinlock is held)
    are not allowed. The function regmap_write calls map->lock, which
    acquires a spinlock in the fast_io case. Since the pwm-fsl-ftm driver
    uses MMIO, the regmap bus of type regmap_mmio is being used which has
    fast_io set to true.
    The MMIO space of the pwm-fsl-ftm driver is reasonable condense, hence
    using the much faster flat regmap cache is anyway the better choice.
    Signed-off-by: default avatarStefan Agner <stefan@agner.ch>
    Cc: Mark Brown <broonie@kernel.org>
    Signed-off-by: default avatarThierry Reding <thierry.reding@gmail.com>