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| author |   Stefan Agner <stefan@agner.ch> | 2016-01-20 18:56:22 -0800 |
|---|---|---|
| committer |   Thierry Reding <thierry.reding@gmail.com> | 2016-04-14 16:54:00 +0200 |
| commit | ad06fdeeef1cbadf86ebbe510e8079abada8b44e (patch) | |
| tree | 239ee3af6e3fc2543aba4c614401456be91a7b1a /drivers/pwm | |
| parent | Linux 4.6-rc1 (diff) | |
| download | linux-dev-ad06fdeeef1cbadf86ebbe510e8079abada8b44e.tar.xz linux-dev-ad06fdeeef1cbadf86ebbe510e8079abada8b44e.zip | |
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 <stefan@agner.ch>
Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Diffstat (limited to 'drivers/pwm')
| -rw-r--r-- | drivers/pwm/pwm-fsl-ftm.c | 2 |
1 files changed, 1 insertions, 1 deletions
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) |