Hello Thierry,
I know you may be very busy but do you have any resolution regarding
this series and the one with title
"[PATCH v2 0/2] extends PWM framework to support PWM dead-times"
Thank you,
Claudiu
On 09.05.2017 15:15, Claudiu Beznea - M18063 wrote:
> Extends PWM framework to support PWM modes. The currently
> implemented PWM modes were called PWM complementary mode
> and PWM push-pull mode. For devices that have more than one
> output per PWM channel:
> - PWM complementary mode is standard working mode; in PWM
> complementary mode the rising and falling edges of the
> channels outputs have opposite levels, same duration and
> same starting time.
> - in PWM push-pull mode the channles outputs has same levels,
> same duration and the rising edges are delayed until the
> beginning of the next period.
> A new member was added in pwm_state structure in order to
> keep the new PWM argument.
> For PWM channels with inputs in DT, the mode could also be
> passed via DT. No new extra field need to be added in device
> tree; since the signal polarity is passed as a flag via DT,
> the field used to pass information for PWM channel polarity
> via DT is also used by PWM mode. Since, for the moment, only
> the complementary and push-pull modes are implemented, only
> one bit in flags used to pass polarity could also be used for
> PWM mode. The other drivers are not affected by this change.
>
> Signed-off-by: Claudiu Beznea <claudiu.beznea@xxxxxxxxxxxxx>
> ---
> Documentation/pwm.txt | 24 +++++++++++++++++---
> drivers/pwm/core.c | 13 +++++++++--
> drivers/pwm/sysfs.c | 52 +++++++++++++++++++++++++++++++++++++++++++
> include/dt-bindings/pwm/pwm.h | 1 +
> include/linux/pwm.h | 37 ++++++++++++++++++++++++++++--
> 5 files changed, 120 insertions(+), 7 deletions(-)
>
> diff --git a/Documentation/pwm.txt b/Documentation/pwm.txt
> index 789b27c..1b6fc59 100644
> --- a/Documentation/pwm.txt
> +++ b/Documentation/pwm.txt
> @@ -59,9 +59,9 @@ In addition to the PWM state, the PWM API also exposes PWM arguments, which
> are the reference PWM config one should use on this PWM.
> PWM arguments are usually platform-specific and allows the PWM user to only
> care about dutycycle relatively to the full period (like, duty = 50% of the
> -period). struct pwm_args contains 2 fields (period and polarity) and should
> -be used to set the initial PWM config (usually done in the probe function
> -of the PWM user). PWM arguments are retrieved with pwm_get_args().
> +period). struct pwm_args contains 3 fields (period, polarity and mode) and
> +should be used to set the initial PWM config (usually done in the probe
> +function of the PWM user). PWM arguments are retrieved with pwm_get_args().
>
> Using PWMs with the sysfs interface
> -----------------------------------
> @@ -100,6 +100,24 @@ enable - Enable/disable the PWM signal (read/write).
> 0 - disabled
> 1 - enabled
>
> +mode - Set PWM signal type (for channels with more than one output
> + per channel)
> + complementary - for an output signal as follow:
> + __ __ __ __
> + PWMH1 __| |__| |__| |__| |__
> + __ __ __ __ __
> + PWML1 |__| |__| |__| |__|
> + <--T-->
> + Where T is the signal period.
> +
> + push-pull - for an output signal as follows:
> + __ __
> + PWMH1 __| |________| |________
> + __ __
> + PWML1 ________| |________| |__
> + <--T-->
> + Where T is the signal period.
> +
> Implementing a PWM driver
> -------------------------
>
> diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
> index a0860b3..4efc92d 100644
> --- a/drivers/pwm/core.c
> +++ b/drivers/pwm/core.c
> @@ -154,9 +154,14 @@ of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
>
> pwm->args.period = args->args[1];
> pwm->args.polarity = PWM_POLARITY_NORMAL;
> + pwm->args.mode = PWM_MODE_COMPLEMENTARY;
>
> - if (args->args_count > 2 && args->args[2] & PWM_POLARITY_INVERTED)
> - pwm->args.polarity = PWM_POLARITY_INVERSED;
> + if (args->args_count > 2) {
> + if (args->args[2] & PWM_POLARITY_INVERTED)
> + pwm->args.polarity = PWM_POLARITY_INVERSED;
> + if (args->args[2] & PWM_MODE_PUSHPULL)
> + pwm->args.mode = PWM_MODE_PUSH_PULL;
> + }
>
> return pwm;
> }
> @@ -579,6 +584,8 @@ int pwm_adjust_config(struct pwm_device *pwm)
> pwm_get_args(pwm, &pargs);
> pwm_get_state(pwm, &state);
>
> + state.mode = pargs.mode;
> +
> /*
> * If the current period is zero it means that either the PWM driver
> * does not support initial state retrieval or the PWM has not yet
> @@ -997,6 +1004,8 @@ static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
> seq_printf(s, " duty: %u ns", state.duty_cycle);
> seq_printf(s, " polarity: %s",
> state.polarity ? "inverse" : "normal");
> + seq_printf(s, " mode: %s",
> + state.mode ? "push-pull" : "complementary");
>
> seq_puts(s, "\n");
> }
> diff --git a/drivers/pwm/sysfs.c b/drivers/pwm/sysfs.c
> index a813239..58f02bf 100644
> --- a/drivers/pwm/sysfs.c
> +++ b/drivers/pwm/sysfs.c
> @@ -223,11 +223,62 @@ static ssize_t capture_show(struct device *child,
> return sprintf(buf, "%u %u\n", result.period, result.duty_cycle);
> }
>
> +static ssize_t mode_show(struct device *child,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + const struct pwm_device *pwm = child_to_pwm_device(child);
> + const char *mode = "unknown";
> + struct pwm_state state;
> +
> + pwm_get_state(pwm, &state);
> +
> + switch (state.mode) {
> + case PWM_MODE_COMPLEMENTARY:
> + mode = "complementary";
> + break;
> +
> + case PWM_MODE_PUSH_PULL:
> + mode = "push-pull";
> + break;
> + }
> +
> + return sprintf(buf, "%s\n", mode);
> +}
> +
> +static ssize_t mode_store(struct device *child,
> + struct device_attribute *attr,
> + const char *buf, size_t size)
> +{
> + struct pwm_export *export = child_to_pwm_export(child);
> + struct pwm_device *pwm = export->pwm;
> + enum pwm_mode mode;
> + struct pwm_state state;
> + int ret;
> +
> + if (sysfs_streq(buf, "complementary"))
> + mode = PWM_MODE_COMPLEMENTARY;
> + else if (sysfs_streq(buf, "push-pull"))
> + mode = PWM_MODE_PUSH_PULL;
> + else
> + return -EINVAL;
> +
> + mutex_lock(&export->lock);
> + pwm_get_state(pwm, &state);
> + state.mode = mode;
> + ret = pwm_apply_state(pwm, &state);
> + mutex_unlock(&export->lock);
> +
> + return ret ? : size;
> +}
> +
> static DEVICE_ATTR_RW(period);
> static DEVICE_ATTR_RW(duty_cycle);
> static DEVICE_ATTR_RW(enable);
> static DEVICE_ATTR_RW(polarity);
> static DEVICE_ATTR_RO(capture);
> +static DEVICE_ATTR_RW(mode);
>
> static struct attribute *pwm_attrs[] = {
> &dev_attr_period.attr,
> @@ -235,6 +286,7 @@ static struct attribute *pwm_attrs[] = {
> &dev_attr_enable.attr,
> &dev_attr_polarity.attr,
> &dev_attr_capture.attr,
> + &dev_attr_mode.attr,
> NULL
> };
> ATTRIBUTE_GROUPS(pwm);
> diff --git a/include/dt-bindings/pwm/pwm.h b/include/dt-bindings/pwm/pwm.h
> index 96f49e8..83bb884 100644
> --- a/include/dt-bindings/pwm/pwm.h
> +++ b/include/dt-bindings/pwm/pwm.h
> @@ -10,5 +10,6 @@
> #define _DT_BINDINGS_PWM_PWM_H
>
> #define PWM_POLARITY_INVERTED (1 << 0)
> +#define PWM_MODE_PUSHPULL (1 << 1)
>
> #endif
> diff --git a/include/linux/pwm.h b/include/linux/pwm.h
> index 08fad7c..d924e55 100644
> --- a/include/linux/pwm.h
> +++ b/include/linux/pwm.h
> @@ -25,9 +25,23 @@ enum pwm_polarity {
> };
>
> /**
> + * enum pwm_mode - PWM mode
> + * @PWM_MODE_COMPLEMENTARY: rising and falling edges of the complementary
> + * PWM channels have opposite levels, same duration and same starting time
> + * @PWM_MODE_PUSH_PULL: rising and falling edges of the complementary PWM
> + * channels have same levels, same duration and are delayed until the
> + * beginning of the next period
> + */
> +enum pwm_mode {
> + PWM_MODE_COMPLEMENTARY,
> + PWM_MODE_PUSH_PULL,
> +};
> +
> +/**
> * struct pwm_args - board-dependent PWM arguments
> * @period: reference period
> * @polarity: reference polarity
> + * @mode: pwm mode
> *
> * This structure describes board-dependent arguments attached to a PWM
> * device. These arguments are usually retrieved from the PWM lookup table or
> @@ -40,6 +54,7 @@ enum pwm_polarity {
> struct pwm_args {
> unsigned int period;
> enum pwm_polarity polarity;
> + enum pwm_mode mode;
> };
>
> enum {
> @@ -52,12 +67,14 @@ enum {
> * @period: PWM period (in nanoseconds)
> * @duty_cycle: PWM duty cycle (in nanoseconds)
> * @polarity: PWM polarity
> + * @mode: PWM mode
> * @enabled: PWM enabled status
> */
> struct pwm_state {
> unsigned int period;
> unsigned int duty_cycle;
> enum pwm_polarity polarity;
> + enum pwm_mode mode;
> bool enabled;
> };
>
> @@ -143,6 +160,21 @@ static inline enum pwm_polarity pwm_get_polarity(const struct pwm_device *pwm)
> return state.polarity;
> }
>
> +static inline void pwm_set_mode(struct pwm_device *pwm, enum pwm_mode mode)
> +{
> + if (pwm)
> + pwm->state.mode = mode;
> +}
> +
> +static inline enum pwm_mode pwm_get_mode(const struct pwm_device *pwm)
> +{
> + struct pwm_state state;
> +
> + pwm_get_state(pwm, &state);
> +
> + return state.mode;
> +}
> +
> static inline void pwm_get_args(const struct pwm_device *pwm,
> struct pwm_args *args)
> {
> @@ -156,8 +188,8 @@ static inline void pwm_get_args(const struct pwm_device *pwm,
> *
> * This functions prepares a state that can later be tweaked and applied
> * to the PWM device with pwm_apply_state(). This is a convenient function
> - * that first retrieves the current PWM state and the replaces the period
> - * and polarity fields with the reference values defined in pwm->args.
> + * that first retrieves the current PWM state and the replaces the period,
> + * polarity and mode fields with the reference values defined in pwm->args.
> * Once the function returns, you can adjust the ->enabled and ->duty_cycle
> * fields according to your needs before calling pwm_apply_state().
> *
> @@ -180,6 +212,7 @@ static inline void pwm_init_state(const struct pwm_device *pwm,
> state->period = args.period;
> state->polarity = args.polarity;
> state->duty_cycle = 0;
> + state->mode = args.mode;
> }
>
> /**
>
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