From: Stefan Agner Date: Thu, 21 Jan 2016 02:56:22 +0000 (-0800) Subject: pwm: fsl-ftm: Use flat regmap cache X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=ad06fdeeef1cbadf86ebbe510e8079abada8b44e;p=openwrt%2Fstaging%2Fblogic.git pwm: fsl-ftm: Use flat regmap cache 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 Cc: Mark Brown Signed-off-by: Thierry Reding --- diff --git a/drivers/pwm/pwm-fsl-ftm.c b/drivers/pwm/pwm-fsl-ftm.c index 7225ac6b3df5..fad968eb75f6 100644 --- a/drivers/pwm/pwm-fsl-ftm.c +++ b/drivers/pwm/pwm-fsl-ftm.c @@ -392,7 +392,7 @@ static const struct regmap_config fsl_pwm_regmap_config = { .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)