From: Stefan Agner <stefan@xxxxxxxx> commit ad06fdeeef1cbadf86ebbe510e8079abada8b44e upstream. 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: Stefan Agner <stefan@xxxxxxxx> Cc: Mark Brown <broonie@xxxxxxxxxx> Signed-off-by: Thierry Reding <thierry.reding@xxxxxxxxx> Signed-off-by: Krzysztof Kozlowski <krzk@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/pwm/pwm-fsl-ftm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/pwm/pwm-fsl-ftm.c +++ b/drivers/pwm/pwm-fsl-ftm.c @@ -392,7 +392,7 @@ static const struct regmap_config fsl_pw .max_register = FTM_PWMLOAD, .volatile_reg = fsl_pwm_volatile_reg, - .cache_type = REGCACHE_RBTREE, + .cache_type = REGCACHE_FLAT, }; static int fsl_pwm_probe(struct platform_device *pdev)
