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 4/6] pwm: sun4i: simplify calculation of the delay time Date: Mon, 31 May 2021 06:46:06 +0200 [thread overview] Message-ID: <20210531044608.1006024-5-roman.beranek@prusa3d.com> (raw) In-Reply-To: <20210531044608.1006024-1-roman.beranek@prusa3d.com> There's no reason to expect a single jiffy has passed since writing the CTRL register except if a preemption has occured in the meantime. Avoid introducing unnecessary complexity and simply wait for the whole period. Signed-off-by: Roman Beranek <roman.beranek@prusa3d.com> --- drivers/pwm/pwm-sun4i.c | 17 ++--------------- 1 file changed, 2 insertions(+), 15 deletions(-) diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c index b3ec59a83d00..8218173ce3f6 100644 --- a/drivers/pwm/pwm-sun4i.c +++ b/drivers/pwm/pwm-sun4i.c @@ -14,7 +14,6 @@ #include <linux/delay.h> #include <linux/err.h> #include <linux/io.h> -#include <linux/jiffies.h> #include <linux/module.h> #include <linux/mutex.h> #include <linux/of.h> @@ -89,7 +88,6 @@ struct sun4i_pwm_chip { void __iomem *base; struct mutex ctrl_lock; const struct sun4i_pwm_data *data; - unsigned long next_period[2]; }; static inline struct sun4i_pwm_chip *to_sun4i_pwm_chip(struct pwm_chip *chip) @@ -242,8 +240,7 @@ static int sun4i_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, struct pwm_state cstate; u32 ctrl, duty = 0, period = 0, val; int ret; - unsigned int delay_us, prescaler = 0; - unsigned long now; + unsigned int prescaler = 0; bool bypass; pwm_get_state(pwm, &cstate); @@ -291,8 +288,6 @@ static int sun4i_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, val = (duty & PWM_DTY_MASK) | PWM_PRD(period); sun4i_pwm_writel(sun4i_pwm, val, PWM_CH_PRD(pwm->hwpwm)); - sun4i_pwm->next_period[pwm->hwpwm] = jiffies + - nsecs_to_jiffies(cstate.period + 1000); if (state->polarity != PWM_POLARITY_NORMAL) ctrl &= ~BIT_CH(PWM_ACT_STATE, pwm->hwpwm); @@ -314,15 +309,7 @@ static int sun4i_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, } /* We need a full period to elapse before disabling the channel. */ - now = jiffies; - if (time_before(now, sun4i_pwm->next_period[pwm->hwpwm])) { - delay_us = jiffies_to_usecs(sun4i_pwm->next_period[pwm->hwpwm] - - now); - if ((delay_us / 500) > MAX_UDELAY_MS) - msleep(delay_us / 1000 + 1); - else - usleep_range(delay_us, delay_us * 2); - } + fsleep(cstate.period / NSEC_PER_USEC + 1); ctrl &= ~BIT_CH(PWM_CLK_GATING, pwm->hwpwm); sun4i_pwm_writel(sun4i_pwm, ctrl, PWM_CTRL_REG); -- 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 4/6] pwm: sun4i: simplify calculation of the delay time Date: Mon, 31 May 2021 06:46:06 +0200 [thread overview] Message-ID: <20210531044608.1006024-5-roman.beranek@prusa3d.com> (raw) In-Reply-To: <20210531044608.1006024-1-roman.beranek@prusa3d.com> There's no reason to expect a single jiffy has passed since writing the CTRL register except if a preemption has occured in the meantime. Avoid introducing unnecessary complexity and simply wait for the whole period. Signed-off-by: Roman Beranek <roman.beranek@prusa3d.com> --- drivers/pwm/pwm-sun4i.c | 17 ++--------------- 1 file changed, 2 insertions(+), 15 deletions(-) diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c index b3ec59a83d00..8218173ce3f6 100644 --- a/drivers/pwm/pwm-sun4i.c +++ b/drivers/pwm/pwm-sun4i.c @@ -14,7 +14,6 @@ #include <linux/delay.h> #include <linux/err.h> #include <linux/io.h> -#include <linux/jiffies.h> #include <linux/module.h> #include <linux/mutex.h> #include <linux/of.h> @@ -89,7 +88,6 @@ struct sun4i_pwm_chip { void __iomem *base; struct mutex ctrl_lock; const struct sun4i_pwm_data *data; - unsigned long next_period[2]; }; static inline struct sun4i_pwm_chip *to_sun4i_pwm_chip(struct pwm_chip *chip) @@ -242,8 +240,7 @@ static int sun4i_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, struct pwm_state cstate; u32 ctrl, duty = 0, period = 0, val; int ret; - unsigned int delay_us, prescaler = 0; - unsigned long now; + unsigned int prescaler = 0; bool bypass; pwm_get_state(pwm, &cstate); @@ -291,8 +288,6 @@ static int sun4i_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, val = (duty & PWM_DTY_MASK) | PWM_PRD(period); sun4i_pwm_writel(sun4i_pwm, val, PWM_CH_PRD(pwm->hwpwm)); - sun4i_pwm->next_period[pwm->hwpwm] = jiffies + - nsecs_to_jiffies(cstate.period + 1000); if (state->polarity != PWM_POLARITY_NORMAL) ctrl &= ~BIT_CH(PWM_ACT_STATE, pwm->hwpwm); @@ -314,15 +309,7 @@ static int sun4i_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, } /* We need a full period to elapse before disabling the channel. */ - now = jiffies; - if (time_before(now, sun4i_pwm->next_period[pwm->hwpwm])) { - delay_us = jiffies_to_usecs(sun4i_pwm->next_period[pwm->hwpwm] - - now); - if ((delay_us / 500) > MAX_UDELAY_MS) - msleep(delay_us / 1000 + 1); - else - usleep_range(delay_us, delay_us * 2); - } + fsleep(cstate.period / NSEC_PER_USEC + 1); ctrl &= ~BIT_CH(PWM_CLK_GATING, pwm->hwpwm); sun4i_pwm_writel(sun4i_pwm, ctrl, PWM_CTRL_REG); -- 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 ` [PATCH 3/6] pwm: sun4i: replace spinlock with a mutex Roman Beranek 2021-05-31 4:46 ` Roman Beranek 2021-05-31 4:46 ` Roman Beranek [this message] 2021-05-31 4:46 ` [PATCH 4/6] pwm: sun4i: simplify calculation of the delay time 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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