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https://github.com/edk2-porting/linux-next.git
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76abbdde2d
Add a simple sysfs interface to the generic PWM framework.
/sys/class/pwm/
`-- pwmchipN/ for each PWM chip
|-- export (w/o) ask the kernel to export a PWM channel
|-- npwm (r/o) number of PWM channels in this PWM chip
|-- pwmX/ for each exported PWM channel
| |-- duty_cycle (r/w) duty cycle (in nanoseconds)
| |-- enable (r/w) enable/disable PWM
| |-- period (r/w) period (in nanoseconds)
| `-- polarity (r/w) polarity of PWM (normal/inversed)
`-- unexport (w/o) return a PWM channel to the kernel
Based on work by Lars Poeschel.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Lars Poeschel <poeschel@lemonage.de>
Cc: Ryan Mallon <rmallon@gmail.com>
Cc: Rob Landley <rob@landley.net>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
309 lines
7.2 KiB
C
309 lines
7.2 KiB
C
#ifndef __LINUX_PWM_H
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#define __LINUX_PWM_H
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#include <linux/err.h>
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#include <linux/of.h>
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struct pwm_device;
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struct seq_file;
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#if IS_ENABLED(CONFIG_PWM) || IS_ENABLED(CONFIG_HAVE_PWM)
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/*
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* pwm_request - request a PWM device
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*/
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struct pwm_device *pwm_request(int pwm_id, const char *label);
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/*
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* pwm_free - free a PWM device
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*/
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void pwm_free(struct pwm_device *pwm);
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/*
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* pwm_config - change a PWM device configuration
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*/
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int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns);
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/*
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* pwm_enable - start a PWM output toggling
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*/
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int pwm_enable(struct pwm_device *pwm);
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/*
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* pwm_disable - stop a PWM output toggling
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*/
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void pwm_disable(struct pwm_device *pwm);
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#else
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static inline struct pwm_device *pwm_request(int pwm_id, const char *label)
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{
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return ERR_PTR(-ENODEV);
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}
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static inline void pwm_free(struct pwm_device *pwm)
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{
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}
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static inline int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
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{
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return -EINVAL;
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}
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static inline int pwm_enable(struct pwm_device *pwm)
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{
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return -EINVAL;
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}
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static inline void pwm_disable(struct pwm_device *pwm)
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{
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}
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#endif
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struct pwm_chip;
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/**
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* enum pwm_polarity - polarity of a PWM signal
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* @PWM_POLARITY_NORMAL: a high signal for the duration of the duty-
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* cycle, followed by a low signal for the remainder of the pulse
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* period
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* @PWM_POLARITY_INVERSED: a low signal for the duration of the duty-
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* cycle, followed by a high signal for the remainder of the pulse
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* period
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*/
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enum pwm_polarity {
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PWM_POLARITY_NORMAL,
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PWM_POLARITY_INVERSED,
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};
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enum {
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PWMF_REQUESTED = 1 << 0,
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PWMF_ENABLED = 1 << 1,
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PWMF_EXPORTED = 1 << 2,
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};
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struct pwm_device {
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const char *label;
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unsigned long flags;
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unsigned int hwpwm;
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unsigned int pwm;
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struct pwm_chip *chip;
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void *chip_data;
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unsigned int period; /* in nanoseconds */
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unsigned int duty_cycle; /* in nanoseconds */
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enum pwm_polarity polarity;
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};
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static inline void pwm_set_period(struct pwm_device *pwm, unsigned int period)
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{
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if (pwm)
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pwm->period = period;
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}
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static inline unsigned int pwm_get_period(struct pwm_device *pwm)
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{
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return pwm ? pwm->period : 0;
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}
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static inline void pwm_set_duty_cycle(struct pwm_device *pwm, unsigned int duty)
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{
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if (pwm)
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pwm->duty_cycle = duty;
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}
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static inline unsigned int pwm_get_duty_cycle(struct pwm_device *pwm)
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{
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return pwm ? pwm->duty_cycle : 0;
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}
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/*
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* pwm_set_polarity - configure the polarity of a PWM signal
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*/
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int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity);
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/**
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* struct pwm_ops - PWM controller operations
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* @request: optional hook for requesting a PWM
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* @free: optional hook for freeing a PWM
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* @config: configure duty cycles and period length for this PWM
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* @set_polarity: configure the polarity of this PWM
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* @enable: enable PWM output toggling
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* @disable: disable PWM output toggling
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* @dbg_show: optional routine to show contents in debugfs
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* @owner: helps prevent removal of modules exporting active PWMs
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*/
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struct pwm_ops {
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int (*request)(struct pwm_chip *chip,
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struct pwm_device *pwm);
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void (*free)(struct pwm_chip *chip,
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struct pwm_device *pwm);
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int (*config)(struct pwm_chip *chip,
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struct pwm_device *pwm,
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int duty_ns, int period_ns);
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int (*set_polarity)(struct pwm_chip *chip,
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struct pwm_device *pwm,
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enum pwm_polarity polarity);
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int (*enable)(struct pwm_chip *chip,
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struct pwm_device *pwm);
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void (*disable)(struct pwm_chip *chip,
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struct pwm_device *pwm);
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#ifdef CONFIG_DEBUG_FS
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void (*dbg_show)(struct pwm_chip *chip,
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struct seq_file *s);
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#endif
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struct module *owner;
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};
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/**
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* struct pwm_chip - abstract a PWM controller
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* @dev: device providing the PWMs
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* @list: list node for internal use
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* @ops: callbacks for this PWM controller
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* @base: number of first PWM controlled by this chip
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* @npwm: number of PWMs controlled by this chip
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* @pwms: array of PWM devices allocated by the framework
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* @can_sleep: must be true if the .config(), .enable() or .disable()
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* operations may sleep
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*/
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struct pwm_chip {
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struct device *dev;
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struct list_head list;
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const struct pwm_ops *ops;
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int base;
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unsigned int npwm;
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struct pwm_device *pwms;
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struct pwm_device * (*of_xlate)(struct pwm_chip *pc,
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const struct of_phandle_args *args);
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unsigned int of_pwm_n_cells;
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bool can_sleep;
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};
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#if IS_ENABLED(CONFIG_PWM)
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int pwm_set_chip_data(struct pwm_device *pwm, void *data);
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void *pwm_get_chip_data(struct pwm_device *pwm);
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int pwmchip_add(struct pwm_chip *chip);
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int pwmchip_remove(struct pwm_chip *chip);
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struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
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unsigned int index,
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const char *label);
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struct pwm_device *of_pwm_xlate_with_flags(struct pwm_chip *pc,
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const struct of_phandle_args *args);
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struct pwm_device *pwm_get(struct device *dev, const char *con_id);
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struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id);
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void pwm_put(struct pwm_device *pwm);
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struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id);
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struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
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const char *con_id);
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void devm_pwm_put(struct device *dev, struct pwm_device *pwm);
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bool pwm_can_sleep(struct pwm_device *pwm);
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#else
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static inline int pwm_set_chip_data(struct pwm_device *pwm, void *data)
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{
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return -EINVAL;
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}
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static inline void *pwm_get_chip_data(struct pwm_device *pwm)
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{
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return NULL;
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}
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static inline int pwmchip_add(struct pwm_chip *chip)
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{
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return -EINVAL;
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}
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static inline int pwmchip_remove(struct pwm_chip *chip)
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{
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return -EINVAL;
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}
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static inline struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
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unsigned int index,
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const char *label)
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{
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return ERR_PTR(-ENODEV);
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}
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static inline struct pwm_device *pwm_get(struct device *dev,
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const char *consumer)
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{
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return ERR_PTR(-ENODEV);
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}
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static inline struct pwm_device *of_pwm_get(struct device_node *np,
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const char *con_id)
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{
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return ERR_PTR(-ENODEV);
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}
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static inline void pwm_put(struct pwm_device *pwm)
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{
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}
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static inline struct pwm_device *devm_pwm_get(struct device *dev,
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const char *consumer)
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{
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return ERR_PTR(-ENODEV);
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}
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static inline struct pwm_device *devm_of_pwm_get(struct device *dev,
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struct device_node *np,
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const char *con_id)
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{
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return ERR_PTR(-ENODEV);
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}
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static inline void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
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{
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}
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static inline bool pwm_can_sleep(struct pwm_device *pwm)
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{
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return false;
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}
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#endif
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struct pwm_lookup {
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struct list_head list;
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const char *provider;
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unsigned int index;
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const char *dev_id;
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const char *con_id;
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};
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#define PWM_LOOKUP(_provider, _index, _dev_id, _con_id) \
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{ \
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.provider = _provider, \
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.index = _index, \
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.dev_id = _dev_id, \
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.con_id = _con_id, \
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}
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#if IS_ENABLED(CONFIG_PWM)
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void pwm_add_table(struct pwm_lookup *table, size_t num);
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#else
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static inline void pwm_add_table(struct pwm_lookup *table, size_t num)
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{
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}
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#endif
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#ifdef CONFIG_PWM_SYSFS
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void pwmchip_sysfs_export(struct pwm_chip *chip);
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void pwmchip_sysfs_unexport(struct pwm_chip *chip);
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#else
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static inline void pwmchip_sysfs_export(struct pwm_chip *chip)
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{
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}
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static inline void pwmchip_sysfs_unexport(struct pwm_chip *chip)
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{
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}
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#endif /* CONFIG_PWM_SYSFS */
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#endif /* __LINUX_PWM_H */
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