From: Roman Beranek <roman.beranek@prusa3d.cz> To: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de> Cc: Thierry Reding <thierry.reding@gmail.com>, Emil Lenngren <emil.lenngren@gmail.com>, Pascal Roeleven <dev@pascalroeleven.nl>, Lee Jones <lee.jones@linaro.org>, Maxime Ripard <mripard@kernel.org>, Chen-Yu Tsai <wens@csie.org>, linux-pwm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-sunxi@lists.linux.dev, linux-sunxi@googlegroups.com Subject: [PATCH 3/6] pwm: sun4i: replace spinlock with a mutex Date: Mon, 31 May 2021 06:46:05 +0200 [thread overview] Message-ID: <20210531044608.1006024-4-roman.beranek@prusa3d.com> (raw) In-Reply-To: <20210531044608.1006024-1-roman.beranek@prusa3d.com> Releasing ctrl_lock for the duration of the delay is not desirable as it allows re-enabling the PWM before the delay is over. Instead, substitute the spinlock with a mutex so that we can sleep while holding it. Signed-off-by: Roman Beranek <roman.beranek@prusa3d.com> --- drivers/pwm/pwm-sun4i.c | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-) diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c index 2777abe66f79..b3ec59a83d00 100644 --- a/drivers/pwm/pwm-sun4i.c +++ b/drivers/pwm/pwm-sun4i.c @@ -16,13 +16,13 @@ #include <linux/io.h> #include <linux/jiffies.h> #include <linux/module.h> +#include <linux/mutex.h> #include <linux/of.h> #include <linux/of_device.h> #include <linux/platform_device.h> #include <linux/pwm.h> #include <linux/reset.h> #include <linux/slab.h> -#include <linux/spinlock.h> #include <linux/time.h> #define PWM_CTRL_REG 0x0 @@ -87,7 +87,7 @@ struct sun4i_pwm_chip { struct clk *clk; struct reset_control *rst; void __iomem *base; - spinlock_t ctrl_lock; + struct mutex ctrl_lock; const struct sun4i_pwm_data *data; unsigned long next_period[2]; }; @@ -265,7 +265,7 @@ static int sun4i_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, return ret; } - spin_lock(&sun4i_pwm->ctrl_lock); + mutex_lock(&sun4i_pwm->ctrl_lock); ctrl = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG); if (sun4i_pwm->data->has_direct_mod_clk_output) { @@ -273,7 +273,7 @@ static int sun4i_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, ctrl |= BIT_CH(PWM_BYPASS, pwm->hwpwm); /* We can skip other parameter */ sun4i_pwm_writel(sun4i_pwm, ctrl, PWM_CTRL_REG); - spin_unlock(&sun4i_pwm->ctrl_lock); + mutex_unlock(&sun4i_pwm->ctrl_lock); return 0; } @@ -308,10 +308,10 @@ static int sun4i_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, sun4i_pwm_writel(sun4i_pwm, ctrl, PWM_CTRL_REG); - spin_unlock(&sun4i_pwm->ctrl_lock); - - if (state->enabled) + if (state->enabled) { + mutex_unlock(&sun4i_pwm->ctrl_lock); return 0; + } /* We need a full period to elapse before disabling the channel. */ now = jiffies; @@ -324,11 +324,9 @@ static int sun4i_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, usleep_range(delay_us, delay_us * 2); } - spin_lock(&sun4i_pwm->ctrl_lock); - ctrl = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG); ctrl &= ~BIT_CH(PWM_CLK_GATING, pwm->hwpwm); sun4i_pwm_writel(sun4i_pwm, ctrl, PWM_CTRL_REG); - spin_unlock(&sun4i_pwm->ctrl_lock); + mutex_unlock(&sun4i_pwm->ctrl_lock); clk_disable_unprepare(sun4i_pwm->clk); @@ -471,7 +469,7 @@ static int sun4i_pwm_probe(struct platform_device *pdev) pwm->chip.of_xlate = of_pwm_xlate_with_flags; pwm->chip.of_pwm_n_cells = 3; - spin_lock_init(&pwm->ctrl_lock); + mutex_init(&pwm->ctrl_lock); ret = pwmchip_add(&pwm->chip); if (ret < 0) { -- 2.31.1
WARNING: multiple messages have this Message-ID (diff)
From: Roman Beranek <roman.beranek@prusa3d.cz> To: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de> Cc: Thierry Reding <thierry.reding@gmail.com>, Emil Lenngren <emil.lenngren@gmail.com>, Pascal Roeleven <dev@pascalroeleven.nl>, Lee Jones <lee.jones@linaro.org>, Maxime Ripard <mripard@kernel.org>, Chen-Yu Tsai <wens@csie.org>, linux-pwm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-sunxi@lists.linux.dev, linux-sunxi@googlegroups.com Subject: [PATCH 3/6] pwm: sun4i: replace spinlock with a mutex Date: Mon, 31 May 2021 06:46:05 +0200 [thread overview] Message-ID: <20210531044608.1006024-4-roman.beranek@prusa3d.com> (raw) In-Reply-To: <20210531044608.1006024-1-roman.beranek@prusa3d.com> Releasing ctrl_lock for the duration of the delay is not desirable as it allows re-enabling the PWM before the delay is over. Instead, substitute the spinlock with a mutex so that we can sleep while holding it. Signed-off-by: Roman Beranek <roman.beranek@prusa3d.com> --- drivers/pwm/pwm-sun4i.c | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-) diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c index 2777abe66f79..b3ec59a83d00 100644 --- a/drivers/pwm/pwm-sun4i.c +++ b/drivers/pwm/pwm-sun4i.c @@ -16,13 +16,13 @@ #include <linux/io.h> #include <linux/jiffies.h> #include <linux/module.h> +#include <linux/mutex.h> #include <linux/of.h> #include <linux/of_device.h> #include <linux/platform_device.h> #include <linux/pwm.h> #include <linux/reset.h> #include <linux/slab.h> -#include <linux/spinlock.h> #include <linux/time.h> #define PWM_CTRL_REG 0x0 @@ -87,7 +87,7 @@ struct sun4i_pwm_chip { struct clk *clk; struct reset_control *rst; void __iomem *base; - spinlock_t ctrl_lock; + struct mutex ctrl_lock; const struct sun4i_pwm_data *data; unsigned long next_period[2]; }; @@ -265,7 +265,7 @@ static int sun4i_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, return ret; } - spin_lock(&sun4i_pwm->ctrl_lock); + mutex_lock(&sun4i_pwm->ctrl_lock); ctrl = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG); if (sun4i_pwm->data->has_direct_mod_clk_output) { @@ -273,7 +273,7 @@ static int sun4i_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, ctrl |= BIT_CH(PWM_BYPASS, pwm->hwpwm); /* We can skip other parameter */ sun4i_pwm_writel(sun4i_pwm, ctrl, PWM_CTRL_REG); - spin_unlock(&sun4i_pwm->ctrl_lock); + mutex_unlock(&sun4i_pwm->ctrl_lock); return 0; } @@ -308,10 +308,10 @@ static int sun4i_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, sun4i_pwm_writel(sun4i_pwm, ctrl, PWM_CTRL_REG); - spin_unlock(&sun4i_pwm->ctrl_lock); - - if (state->enabled) + if (state->enabled) { + mutex_unlock(&sun4i_pwm->ctrl_lock); return 0; + } /* We need a full period to elapse before disabling the channel. */ now = jiffies; @@ -324,11 +324,9 @@ static int sun4i_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, usleep_range(delay_us, delay_us * 2); } - spin_lock(&sun4i_pwm->ctrl_lock); - ctrl = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG); ctrl &= ~BIT_CH(PWM_CLK_GATING, pwm->hwpwm); sun4i_pwm_writel(sun4i_pwm, ctrl, PWM_CTRL_REG); - spin_unlock(&sun4i_pwm->ctrl_lock); + mutex_unlock(&sun4i_pwm->ctrl_lock); clk_disable_unprepare(sun4i_pwm->clk); @@ -471,7 +469,7 @@ static int sun4i_pwm_probe(struct platform_device *pdev) pwm->chip.of_xlate = of_pwm_xlate_with_flags; pwm->chip.of_pwm_n_cells = 3; - spin_lock_init(&pwm->ctrl_lock); + mutex_init(&pwm->ctrl_lock); ret = pwmchip_add(&pwm->chip); if (ret < 0) { -- 2.31.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-05-31 4:46 UTC|newest] Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-05-31 4:46 [PATCH 0/6] pwm: sun4i: only wait 2 cycles prior to disabling Roman Beranek 2021-05-31 4:46 ` Roman Beranek 2021-05-31 4:46 ` [PATCH 1/6] pwm: sun4i: enable clk prior to getting its rate Roman Beranek 2021-05-31 4:46 ` Roman Beranek 2021-06-07 8:00 ` Uwe Kleine-König 2021-06-07 8:00 ` Uwe Kleine-König 2021-05-31 4:46 ` [PATCH 2/6] pwm: sun4i: disable EN bit prior to the delay Roman Beranek 2021-05-31 4:46 ` Roman Beranek 2021-06-07 8:07 ` Uwe Kleine-König 2021-06-07 8:07 ` Uwe Kleine-König 2021-05-31 4:46 ` Roman Beranek [this message] 2021-05-31 4:46 ` [PATCH 3/6] pwm: sun4i: replace spinlock with a mutex Roman Beranek 2021-05-31 4:46 ` [PATCH 4/6] pwm: sun4i: simplify calculation of the delay time Roman Beranek 2021-05-31 4:46 ` Roman Beranek 2021-05-31 4:46 ` [PATCH 5/6] pwm: sun4i: shorten the delay to 2 cycles Roman Beranek 2021-05-31 4:46 ` Roman Beranek 2021-05-31 4:46 ` [PATCH 6/6] pwm: sun4i: don't delay if the PWM is already off Roman Beranek 2021-05-31 4:46 ` Roman Beranek 2021-06-10 13:41 ` Pascal Roeleven 2021-06-10 13:41 ` Pascal Roeleven 2021-05-31 19:07 ` [PATCH 0/6] pwm: sun4i: only wait 2 cycles prior to disabling Pascal Roeleven 2021-05-31 19:07 ` Pascal Roeleven 2021-05-31 20:01 ` Emil Lenngren 2021-05-31 20:01 ` Emil Lenngren 2021-05-31 20:20 ` Pascal Roeleven 2021-05-31 20:20 ` Pascal Roeleven 2021-06-08 12:28 ` Pascal Roeleven 2021-06-08 12:28 ` Pascal Roeleven
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