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[178.41.255.34]) by smtp.googlemail.com with ESMTPSA id 129sm8853400wmd.48.2020.07.24.14.37.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 24 Jul 2020 14:37:34 -0700 (PDT) From: Martin Botka Cc: Fenglin Wu , Konrad Dybcio , Martin Botka , Jacek Anaszewski , Pavel Machek , Dan Murphy , Rob Herring , Thierry Reding , =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= , Lee Jones , linux-leds@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org Subject: [PATCH RCC 1/6] pwm: Add different PWM output types support Date: Fri, 24 Jul 2020 23:36:51 +0200 Message-Id: <20200724213659.273599-2-martin.botka1@gmail.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200724213659.273599-1-martin.botka1@gmail.com> References: <20200724213659.273599-1-martin.botka1@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit To: unlisted-recipients:; (no To-header on input) Sender: linux-pwm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pwm@vger.kernel.org From: Fenglin Wu Normally, PWM channel has fixed output until software request to change its settings. There are some PWM devices which their outputs could be changed autonomously according to a predefined pattern programmed in hardware. Add pwm_output_type enum type to identify these two different PWM types and add relevant helper functions to set and get PWM output types and pattern. Signed-off-by: Fenglin Wu [konradybcio@gmail.com: Fast-forward from kernel 4.14 to 5.8] Signed-off-by: Konrad Dybcio Signed-off-by: Martin Botka --- drivers/pwm/core.c | 26 +++++++++++++++++ drivers/pwm/sysfs.c | 50 ++++++++++++++++++++++++++++++++ include/linux/pwm.h | 69 +++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 145 insertions(+) diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index 004b2ea9b5fd..f3aa44106962 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -304,6 +304,7 @@ int pwmchip_add_with_polarity(struct pwm_chip *chip, pwm->pwm = chip->base + i; pwm->hwpwm = i; pwm->state.polarity = polarity; + pwm->state.output_type = PWM_OUTPUT_FIXED; radix_tree_insert(&pwm_tree, pwm->pwm, pwm); } @@ -627,6 +628,31 @@ int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state) pwm->state.polarity = state->polarity; } + if (state->output_type != pwm->state.output_type) { + if (!pwm->chip->ops->set_output_type) + return -ENOTSUPP; + + err = pwm->chip->ops->set_output_type(pwm->chip, pwm, + state->output_type); + if (err) + return err; + + pwm->state.output_type = state->output_type; + } + + if (state->output_pattern != pwm->state.output_pattern && + state->output_pattern != NULL) { + if (!pwm->chip->ops->set_output_pattern) + return -ENOTSUPP; + + err = pwm->chip->ops->set_output_pattern(pwm->chip, + pwm, state->output_pattern); + if (err) + return err; + + pwm->state.output_pattern = state->output_pattern; + } + if (state->period != pwm->state.period || state->duty_cycle != pwm->state.duty_cycle) { err = chip->ops->config(pwm->chip, pwm, diff --git a/drivers/pwm/sysfs.c b/drivers/pwm/sysfs.c index 2389b8669846..4ee1e81db0bc 100644 --- a/drivers/pwm/sysfs.c +++ b/drivers/pwm/sysfs.c @@ -215,11 +215,60 @@ static ssize_t capture_show(struct device *child, return sprintf(buf, "%u %u\n", result.period, result.duty_cycle); } +static ssize_t output_type_show(struct device *child, + struct device_attribute *attr, + char *buf) +{ + const struct pwm_device *pwm = child_to_pwm_device(child); + const char *output_type = "unknown"; + struct pwm_state state; + + pwm_get_state(pwm, &state); + switch (state.output_type) { + case PWM_OUTPUT_FIXED: + output_type = "fixed"; + break; + case PWM_OUTPUT_MODULATED: + output_type = "modulated"; + break; + default: + break; + } + + return snprintf(buf, PAGE_SIZE, "%s\n", output_type); +} + +static ssize_t output_type_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; + struct pwm_state state; + int ret = -EINVAL; + + mutex_lock(&export->lock); + pwm_get_state(pwm, &state); + if (sysfs_streq(buf, "fixed")) + state.output_type = PWM_OUTPUT_FIXED; + else if (sysfs_streq(buf, "modulated")) + state.output_type = PWM_OUTPUT_MODULATED; + else + goto unlock; + + ret = pwm_apply_state(pwm, &state); +unlock: + 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(output_type); static struct attribute *pwm_attrs[] = { &dev_attr_period.attr, @@ -227,6 +276,7 @@ static struct attribute *pwm_attrs[] = { &dev_attr_enable.attr, &dev_attr_polarity.attr, &dev_attr_capture.attr, + &dev_attr_output_type.attr, NULL }; ATTRIBUTE_GROUPS(pwm); diff --git a/include/linux/pwm.h b/include/linux/pwm.h index 2635b2a55090..10a102efadc4 100644 --- a/include/linux/pwm.h +++ b/include/linux/pwm.h @@ -48,6 +48,29 @@ enum { PWMF_EXPORTED = 1 << 1, }; +/* + * enum pwm_output_type - output type of the PWM signal + * @PWM_OUTPUT_FIXED: PWM output is fixed until a change request + * @PWM_OUTPUT_MODULATED: PWM output is modulated in hardware + * autonomously with a predefined pattern + */ +enum pwm_output_type { + PWM_OUTPUT_FIXED = 1 << 0, + PWM_OUTPUT_MODULATED = 1 << 1, +}; + +/* + * struct pwm_output_pattern - PWM duty pattern for MODULATED duty type + * @duty_pattern: PWM duty cycles in the pattern for duty modulation + * @num_entries: number of entries in the pattern + * @cycles_per_duty: number of PWM period cycles an entry stays at + */ +struct pwm_output_pattern { + unsigned int *duty_pattern; + unsigned int num_entries; + unsigned int cycles_per_duty; +}; + /* * struct pwm_state - state of a PWM channel * @period: PWM period (in nanoseconds) @@ -59,6 +82,8 @@ struct pwm_state { unsigned int period; unsigned int duty_cycle; enum pwm_polarity polarity; + enum pwm_output_type output_type; + struct pwm_output_pattern *output_pattern; bool enabled; }; @@ -146,6 +171,26 @@ static inline enum pwm_polarity pwm_get_polarity(const struct pwm_device *pwm) return state.polarity; } +static inline enum pwm_output_type pwm_get_output_type( + const struct pwm_device *pwm) +{ + struct pwm_state state; + + pwm_get_state(pwm, &state); + + return state.output_type; +} + +static inline struct pwm_output_pattern *pwm_get_output_pattern( + struct pwm_device *pwm) +{ + struct pwm_state state; + + pwm_get_state(pwm, &state); + + return pwm->state.output_pattern ?: NULL; +} + static inline void pwm_get_args(const struct pwm_device *pwm, struct pwm_args *args) { @@ -254,6 +299,9 @@ pwm_set_relative_duty_cycle(struct pwm_state *state, unsigned int duty_cycle, * @set_polarity: configure the polarity of this PWM * @enable: enable PWM output toggling * @disable: disable PWM output toggling + * @get_output_type_supported: get the supported output type + * @set_output_type: set PWM output type + * @set_output_pattern: set the pattern for the modulated output */ struct pwm_ops { int (*request)(struct pwm_chip *chip, struct pwm_device *pwm); @@ -273,6 +321,13 @@ struct pwm_ops { enum pwm_polarity polarity); int (*enable)(struct pwm_chip *chip, struct pwm_device *pwm); void (*disable)(struct pwm_chip *chip, struct pwm_device *pwm); + int (*get_output_type_supported)(struct pwm_chip *chip, + struct pwm_device *pwm); + int (*set_output_type)(struct pwm_chip *chip, struct pwm_device *pwm, + enum pwm_output_type output_type); + int (*set_output_pattern)(struct pwm_chip *chip, + struct pwm_device *pwm, + struct pwm_output_pattern *output_pattern); }; /** @@ -318,6 +373,20 @@ void pwm_free(struct pwm_device *pwm); int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state); int pwm_adjust_config(struct pwm_device *pwm); +/* + * pwm_output_type_support() + * @pwm: PWM device + * + * Returns: output types supported by the PWM device + */ +static inline int pwm_get_output_type_supported(struct pwm_device *pwm) +{ + if (pwm->chip->ops->get_output_type_supported != NULL) + return pwm->chip->ops->get_output_type_supported(pwm->chip, pwm); + else + return PWM_OUTPUT_FIXED; +} + /** * pwm_config() - change a PWM device configuration * @pwm: PWM device -- 2.27.0