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clocksource/drivers/samsung_pwm: Switch to raw_spinlock_t type

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Samsung PWM timer might be used as a clock source on some legacy systems.
When PREEMPT_RT is enabled on ARM, regular spinlock is converted to a
sleeping lock (mutex-based), which must not be used in atomic context
such as hard interrupt handlers. Switch the samsung_pwm_lock to the
raw_spinlock, which remains a true non-sleeping spinlock even
under PREEMPT_RT.

Fixes: 7aac482e62 ("clocksource: samsung_pwm_timer: Make PWM spinlock global")
Fixes: f11899894c ("clocksource: add samsung pwm timer driver")
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Uwe Kleine-König <ukleinek@kernel.org>
Link: https://patch.msgid.link/20260713085653.1145015-1-m.szyprowski@samsung.com
This commit is contained in:
Marek Szyprowski 2026-07-13 10:56:53 +02:00 committed by Daniel Lezcano
parent e998c6300e
commit 3b212f9d70
3 changed files with 23 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
drivers/clocksource/samsung_pwm_timer.c
View File

@ -56,7 +56,7 @@
#define TCON_AUTORELOAD(chan) \
((chan < 5) ? _TCON_AUTORELOAD(chan) : _TCON_AUTORELOAD4(chan))
DEFINE_SPINLOCK(samsung_pwm_lock);
DEFINE_RAW_SPINLOCK(samsung_pwm_lock);
EXPORT_SYMBOL(samsung_pwm_lock);
struct samsung_pwm_clocksource {
@ -87,14 +87,14 @@ static void samsung_timer_set_prescale(unsigned int channel, u16 prescale)
if (channel >= 2)
shift = TCFG0_PRESCALER1_SHIFT;
spin_lock_irqsave(&samsung_pwm_lock, flags);
raw_spin_lock_irqsave(&samsung_pwm_lock, flags);
reg = readl(pwm.base + REG_TCFG0);
reg &= ~(TCFG0_PRESCALER_MASK << shift);
reg |= (prescale - 1) << shift;
writel(reg, pwm.base + REG_TCFG0);
spin_unlock_irqrestore(&samsung_pwm_lock, flags);
raw_spin_unlock_irqrestore(&samsung_pwm_lock, flags);
}
static void samsung_timer_set_divisor(unsigned int channel, u8 divisor)
@ -106,14 +106,14 @@ static void samsung_timer_set_divisor(unsigned int channel, u8 divisor)
bits = (fls(divisor) - 1) - pwm.variant.div_base;
spin_lock_irqsave(&samsung_pwm_lock, flags);
raw_spin_lock_irqsave(&samsung_pwm_lock, flags);
reg = readl(pwm.base + REG_TCFG1);
reg &= ~(TCFG1_MUX_MASK << shift);
reg |= bits << shift;
writel(reg, pwm.base + REG_TCFG1);
spin_unlock_irqrestore(&samsung_pwm_lock, flags);
raw_spin_unlock_irqrestore(&samsung_pwm_lock, flags);
}
static void samsung_time_stop(unsigned int channel)
@ -124,13 +124,13 @@ static void samsung_time_stop(unsigned int channel)
if (channel > 0)
++channel;
spin_lock_irqsave(&samsung_pwm_lock, flags);
raw_spin_lock_irqsave(&samsung_pwm_lock, flags);
tcon = readl_relaxed(pwm.base + REG_TCON);
tcon &= ~TCON_START(channel);
writel_relaxed(tcon, pwm.base + REG_TCON);
spin_unlock_irqrestore(&samsung_pwm_lock, flags);
raw_spin_unlock_irqrestore(&samsung_pwm_lock, flags);
}
static void samsung_time_setup(unsigned int channel, unsigned long tcnt)
@ -142,7 +142,7 @@ static void samsung_time_setup(unsigned int channel, unsigned long tcnt)
if (tcon_chan > 0)
++tcon_chan;
spin_lock_irqsave(&samsung_pwm_lock, flags);
raw_spin_lock_irqsave(&samsung_pwm_lock, flags);
tcon = readl_relaxed(pwm.base + REG_TCON);
@ -153,7 +153,7 @@ static void samsung_time_setup(unsigned int channel, unsigned long tcnt)
writel_relaxed(tcnt, pwm.base + REG_TCMPB(channel));
writel_relaxed(tcon, pwm.base + REG_TCON);
spin_unlock_irqrestore(&samsung_pwm_lock, flags);
raw_spin_unlock_irqrestore(&samsung_pwm_lock, flags);
}
static void samsung_time_start(unsigned int channel, bool periodic)
@ -164,7 +164,7 @@ static void samsung_time_start(unsigned int channel, bool periodic)
if (channel > 0)
++channel;
spin_lock_irqsave(&samsung_pwm_lock, flags);
raw_spin_lock_irqsave(&samsung_pwm_lock, flags);
tcon = readl_relaxed(pwm.base + REG_TCON);
@ -178,7 +178,7 @@ static void samsung_time_start(unsigned int channel, bool periodic)
writel_relaxed(tcon, pwm.base + REG_TCON);
spin_unlock_irqrestore(&samsung_pwm_lock, flags);
raw_spin_unlock_irqrestore(&samsung_pwm_lock, flags);
}
static int samsung_set_next_event(unsigned long cycles,

22
drivers/pwm/pwm-samsung.c
View File

@ -102,7 +102,7 @@ struct samsung_pwm_chip {
* IP. Should this change, both drivers will need to be modified to
* properly synchronize accesses to particular instances.
*/
static DEFINE_SPINLOCK(samsung_pwm_lock);
static DEFINE_RAW_SPINLOCK(samsung_pwm_lock);
#endif
static inline
@ -141,14 +141,14 @@ static void pwm_samsung_set_divisor(struct samsung_pwm_chip *our_chip,
bits = (fls(divisor) - 1) - our_chip->variant.div_base;
spin_lock_irqsave(&samsung_pwm_lock, flags);
raw_spin_lock_irqsave(&samsung_pwm_lock, flags);
reg = readl(our_chip->base + REG_TCFG1);
reg &= ~(TCFG1_MUX_MASK << shift);
reg |= bits << shift;
writel(reg, our_chip->base + REG_TCFG1);
spin_unlock_irqrestore(&samsung_pwm_lock, flags);
raw_spin_unlock_irqrestore(&samsung_pwm_lock, flags);
}
static int pwm_samsung_is_tdiv(struct samsung_pwm_chip *our_chip, unsigned int chan)
@ -249,7 +249,7 @@ static int pwm_samsung_enable(struct pwm_chip *chip, struct pwm_device *pwm)
unsigned long flags;
u32 tcon;
spin_lock_irqsave(&samsung_pwm_lock, flags);
raw_spin_lock_irqsave(&samsung_pwm_lock, flags);
tcon = readl(our_chip->base + REG_TCON);
@ -263,7 +263,7 @@ static int pwm_samsung_enable(struct pwm_chip *chip, struct pwm_device *pwm)
our_chip->disabled_mask &= ~BIT(pwm->hwpwm);
spin_unlock_irqrestore(&samsung_pwm_lock, flags);
raw_spin_unlock_irqrestore(&samsung_pwm_lock, flags);
return 0;
}
@ -275,7 +275,7 @@ static void pwm_samsung_disable(struct pwm_chip *chip, struct pwm_device *pwm)
unsigned long flags;
u32 tcon;
spin_lock_irqsave(&samsung_pwm_lock, flags);
raw_spin_lock_irqsave(&samsung_pwm_lock, flags);
tcon = readl(our_chip->base + REG_TCON);
tcon &= ~TCON_AUTORELOAD(tcon_chan);
@ -290,7 +290,7 @@ static void pwm_samsung_disable(struct pwm_chip *chip, struct pwm_device *pwm)
our_chip->disabled_mask |= BIT(pwm->hwpwm);
spin_unlock_irqrestore(&samsung_pwm_lock, flags);
raw_spin_unlock_irqrestore(&samsung_pwm_lock, flags);
}
static void pwm_samsung_manual_update(struct samsung_pwm_chip *our_chip,
@ -298,11 +298,11 @@ static void pwm_samsung_manual_update(struct samsung_pwm_chip *our_chip,
{
unsigned long flags;
spin_lock_irqsave(&samsung_pwm_lock, flags);
raw_spin_lock_irqsave(&samsung_pwm_lock, flags);
__pwm_samsung_manual_update(our_chip, pwm);
spin_unlock_irqrestore(&samsung_pwm_lock, flags);
raw_spin_unlock_irqrestore(&samsung_pwm_lock, flags);
}
static int __pwm_samsung_config(struct pwm_chip *chip, struct pwm_device *pwm,
@ -390,7 +390,7 @@ static void pwm_samsung_set_invert(struct samsung_pwm_chip *our_chip,
unsigned long flags;
u32 tcon;
spin_lock_irqsave(&samsung_pwm_lock, flags);
raw_spin_lock_irqsave(&samsung_pwm_lock, flags);
tcon = readl(our_chip->base + REG_TCON);
@ -404,7 +404,7 @@ static void pwm_samsung_set_invert(struct samsung_pwm_chip *our_chip,
writel(tcon, our_chip->base + REG_TCON);
spin_unlock_irqrestore(&samsung_pwm_lock, flags);
raw_spin_unlock_irqrestore(&samsung_pwm_lock, flags);
}
static int pwm_samsung_set_polarity(struct pwm_chip *chip,

2
include/clocksource/samsung_pwm.h
View File

@ -15,7 +15,7 @@
* spinlock is not shared between both drivers.
*/
#ifdef CONFIG_CLKSRC_SAMSUNG_PWM
extern spinlock_t samsung_pwm_lock;
extern raw_spinlock_t samsung_pwm_lock;
#endif
struct samsung_pwm_variant {