Messages in this thread Patch in this message | | | From | Guru Das Srinagesh <> | Subject | [PATCH 2/2] pwm: core: Add option to config PWM duty/period with u64 data length | Date | Fri, 13 Sep 2019 15:57:44 -0700 |
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From: Fenglin Wu <fenglinw@codeaurora.org>
Currently, PWM core driver provides interfaces for configuring PWM period and duty length in nanoseconds with an integer data type, so the max period can be only set to ~2.147 seconds. Add interfaces which can set PWM period and duty with u64 data type to remove this limitation.
Change-Id: Ic8722088510d447fc939ab6a5014711aef1b832f Signed-off-by: Fenglin Wu <fenglinw@codeaurora.org> Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org> --- drivers/pwm/core.c | 20 ++++++--- drivers/pwm/sysfs.c | 6 +-- include/linux/pwm.h | 115 ++++++++++++++++++++++++++++++++++++++++++++++++---- 3 files changed, 126 insertions(+), 15 deletions(-)
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index 960a451..02ad16b 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -526,9 +526,19 @@ int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state) if (state->period != pwm->state.period || state->duty_cycle != pwm->state.duty_cycle) { - err = pwm->chip->ops->config(pwm->chip, pwm, - state->duty_cycle, - state->period); + if (pwm->chip->ops->config_extend) { + err = pwm->chip->ops->config_extend(pwm->chip, + pwm, state->duty_cycle, + state->period); + } else { + if (state->period > UINT_MAX) + pr_warn("period %llu duty_cycle %llu will be truncated\n", + state->period, + state->duty_cycle); + err = pwm->chip->ops->config(pwm->chip, pwm, + state->duty_cycle, + state->period); + } if (err) return err; @@ -1181,8 +1191,8 @@ static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s) if (state.enabled) seq_puts(s, " enabled"); - seq_printf(s, " period: %u ns", state.period); - seq_printf(s, " duty: %u ns", state.duty_cycle); + seq_printf(s, " period: %llu ns", state.period); + seq_printf(s, " duty: %llu ns", state.duty_cycle); seq_printf(s, " polarity: %s", state.polarity ? "inverse" : "normal"); diff --git a/drivers/pwm/sysfs.c b/drivers/pwm/sysfs.c index ab703f2..ef78c40 100644 --- a/drivers/pwm/sysfs.c +++ b/drivers/pwm/sysfs.c @@ -42,7 +42,7 @@ static ssize_t period_show(struct device *child, pwm_get_state(pwm, &state); - return sprintf(buf, "%u\n", state.period); + return sprintf(buf, "%llu\n", state.period); } static ssize_t period_store(struct device *child, @@ -77,7 +77,7 @@ static ssize_t duty_cycle_show(struct device *child, pwm_get_state(pwm, &state); - return sprintf(buf, "%u\n", state.duty_cycle); + return sprintf(buf, "%llu\n", state.duty_cycle); } static ssize_t duty_cycle_store(struct device *child, @@ -212,7 +212,7 @@ static ssize_t capture_show(struct device *child, if (ret) return ret; - return sprintf(buf, "%u %u\n", result.period, result.duty_cycle); + return sprintf(buf, "%llu %llu\n", result.period, result.duty_cycle); } static ssize_t output_type_show(struct device *child, diff --git a/include/linux/pwm.h b/include/linux/pwm.h index 416f08e..d714385 100644 --- a/include/linux/pwm.h +++ b/include/linux/pwm.h @@ -39,7 +39,7 @@ enum pwm_polarity { * current PWM hardware state. */ struct pwm_args { - unsigned int period; + u64 period; enum pwm_polarity polarity; }; @@ -66,9 +66,9 @@ enum pwm_output_type { * @cycles_per_duty: number of PWM period cycles an entry stays at */ struct pwm_output_pattern { - unsigned int *duty_pattern; + u64 *duty_pattern; unsigned int num_entries; - unsigned int cycles_per_duty; + u64 cycles_per_duty; }; /* @@ -79,8 +79,8 @@ struct pwm_output_pattern { * @enabled: PWM enabled status */ struct pwm_state { - unsigned int period; - unsigned int duty_cycle; + u64 period; + u64 duty_cycle; enum pwm_polarity polarity; enum pwm_output_type output_type; struct pwm_output_pattern *output_pattern; @@ -136,12 +136,30 @@ static inline void pwm_set_period(struct pwm_device *pwm, unsigned int period) pwm->state.period = period; } +static inline void pwm_set_period_extend(struct pwm_device *pwm, u64 period) +{ + if (pwm) + pwm->state.period = period; +} + static inline unsigned int pwm_get_period(const struct pwm_device *pwm) { struct pwm_state state; pwm_get_state(pwm, &state); + if (state.period > UINT_MAX) + pr_warn("PWM period %llu is truncated\n", state.period); + + return (unsigned int)state.period; +} + +static inline u64 pwm_get_period_extend(const struct pwm_device *pwm) +{ + struct pwm_state state; + + pwm_get_state(pwm, &state); + return state.period; } @@ -151,12 +169,30 @@ static inline void pwm_set_duty_cycle(struct pwm_device *pwm, unsigned int duty) pwm->state.duty_cycle = duty; } +static inline void pwm_set_duty_cycle_extend(struct pwm_device *pwm, u64 duty) +{ + if (pwm) + pwm->state.duty_cycle = duty; +} + static inline unsigned int pwm_get_duty_cycle(const struct pwm_device *pwm) { struct pwm_state state; pwm_get_state(pwm, &state); + if (state.duty_cycle > UINT_MAX) + pr_warn("PWM duty cycle %llu is truncated\n", state.duty_cycle); + + return (unsigned int)state.duty_cycle; +} + +static inline u64 pwm_get_duty_cycle_extend(const struct pwm_device *pwm) +{ + struct pwm_state state; + + pwm_get_state(pwm, &state); + return state.duty_cycle; } @@ -300,6 +336,8 @@ static inline void pwm_init_state(const struct pwm_device *pwm, * @set_output_pattern: set the pattern for the modulated output * @owner: helps prevent removal of modules exporting active PWMs * @config: configure duty cycles and period length for this PWM + * @config_extend: configure duty cycles and period length for this + * PWM with u64 data type * @set_polarity: configure the polarity of this PWM * @enable: enable PWM output toggling * @disable: disable PWM output toggling @@ -325,6 +363,8 @@ struct pwm_ops { /* Only used by legacy drivers */ int (*config)(struct pwm_chip *chip, struct pwm_device *pwm, int duty_ns, int period_ns); + int (*config_extend)(struct pwm_chip *chip, struct pwm_device *pwm, + u64 duty_ns, u64 period_ns); int (*set_polarity)(struct pwm_chip *chip, struct pwm_device *pwm, enum pwm_polarity polarity); int (*enable)(struct pwm_chip *chip, struct pwm_device *pwm); @@ -363,8 +403,8 @@ struct pwm_chip { * @duty_cycle: duty cycle of the PWM signal (in nanoseconds) */ struct pwm_capture { - unsigned int period; - unsigned int duty_cycle; + u64 period; + u64 duty_cycle; }; #if IS_ENABLED(CONFIG_PWM) @@ -418,6 +458,67 @@ static inline int pwm_config(struct pwm_device *pwm, int duty_ns, } /** + * pwm_config_extend() - change PWM period and duty length with u64 data type + * @pwm: PWM device + * @duty_ns: "on" time (in nanoseconds) + * @period_ns: duration (in nanoseconds) of one cycle + * + * Returns: 0 on success or a negative error code on failure. + */ +static inline int pwm_config_extend(struct pwm_device *pwm, u64 duty_ns, + u64 period_ns) +{ + struct pwm_state state; + + if (!pwm) + return -EINVAL; + + pwm_get_state(pwm, &state); + if (state.duty_cycle == duty_ns && state.period == period_ns) + return 0; + + state.duty_cycle = duty_ns; + state.period = period_ns; + return pwm_apply_state(pwm, &state); +} + +/** + * pwm_set_polarity() - configure the polarity of a PWM signal + * @pwm: PWM device + * @polarity: new polarity of the PWM signal + * + * Note that the polarity cannot be configured while the PWM device is + * enabled. + * + * Returns: 0 on success or a negative error code on failure. + */ +static inline int pwm_set_polarity(struct pwm_device *pwm, + enum pwm_polarity polarity) +{ + struct pwm_state state; + + if (!pwm) + return -EINVAL; + + pwm_get_state(pwm, &state); + if (state.polarity == polarity) + return 0; + + /* + * Changing the polarity of a running PWM without adjusting the + * dutycycle/period value is a bit risky (can introduce glitches). + * Return -EBUSY in this case. + * Note that this is allowed when using pwm_apply_state() because + * the user specifies all the parameters. + */ + if (state.enabled) + return -EBUSY; + + state.polarity = polarity; + return pwm_apply_state(pwm, &state); +} + +/** * pwm_enable() - start a PWM output toggling * @pwm: PWM device * -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
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