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Sangyun Kim
dd60f26fd8
[ Upstream commit68637b68af] atmel_tcb_pwm_apply() holds tcbpwmc->lock as a spinlock via guard(spinlock)() and then calls atmel_tcb_pwm_config(), which calls clk_get_rate() twice. clk_get_rate() acquires clk_prepare_lock (a mutex), so this is a sleep-in-atomic-context violation. On CONFIG_DEBUG_ATOMIC_SLEEP kernels every pwm_apply_state() that enables or reconfigures the PWM triggers a "BUG: sleeping function called from invalid context" warning. Acquire exclusive control over the clock rates with clk_rate_exclusive_get() at probe time and cache the rates in struct atmel_tcb_pwm_chip, then read the cached rates from atmel_tcb_pwm_config(). This keeps the spinlock-based mutual exclusion introduced in commit37f7707077("pwm: atmel-tcb: Fix race condition and convert to guards") and removes the sleeping calls from the atomic section. With no sleeping calls left in .apply() and the regmap-mmio bus already running with fast_io=true, also mark the chip as atomic so consumers can use pwm_apply_atomic() from atomic context. Fixes:37f7707077("pwm: atmel-tcb: Fix race condition and convert to guards") Signed-off-by: Sangyun Kim <sangyun.kim@snu.ac.kr> Link: https://patch.msgid.link/20260419080838.3192357-1-sangyun.kim@snu.ac.kr [ukleinek: Ensure .clk is enabled before calling clk_get_rate on it.] Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
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