include/linux/pwm.h

   1 #ifndef __LINUX_PWM_H
   2 #define __LINUX_PWM_H
   3
   4 #include <linux/err.h>
   5 #include <linux/mutex.h>
   6 #include <linux/of.h>
   7
   8 struct pwm_device;
   9 struct seq_file;
  10
  11 #if IS_ENABLED(CONFIG_PWM)
  12 /*
  13  * pwm_request - request a PWM device
  14  */
  15 struct pwm_device *pwm_request(int pwm_id, const char *label);
  16
  17 /*
  18  * pwm_free - free a PWM device
  19  */
  20 void pwm_free(struct pwm_device *pwm);
  21
  22 /*
  23  * pwm_config - change a PWM device configuration
  24  */
  25 int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns);
  26
  27 /*
  28  * pwm_enable - start a PWM output toggling
  29  */
  30 int pwm_enable(struct pwm_device *pwm);
  31
  32 /*
  33  * pwm_disable - stop a PWM output toggling
  34  */
  35 void pwm_disable(struct pwm_device *pwm);
  36 #else
  37 static inline struct pwm_device *pwm_request(int pwm_id, const char *label)
  38 {
  39         return ERR_PTR(-ENODEV);
  40 }
  41
  42 static inline void pwm_free(struct pwm_device *pwm)
  43 {
  44 }
  45
  46 static inline int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
  47 {
  48         return -EINVAL;
  49 }
  50
  51 static inline int pwm_enable(struct pwm_device *pwm)
  52 {
  53         return -EINVAL;
  54 }
  55
  56 static inline void pwm_disable(struct pwm_device *pwm)
  57 {
  58 }
  59 #endif
  60
  61 struct pwm_chip;
  62
  63 /**
  64  * enum pwm_polarity - polarity of a PWM signal
  65  * @PWM_POLARITY_NORMAL: a high signal for the duration of the duty-
  66  * cycle, followed by a low signal for the remainder of the pulse
  67  * period
  68  * @PWM_POLARITY_INVERSED: a low signal for the duration of the duty-
  69  * cycle, followed by a high signal for the remainder of the pulse
  70  * period
  71  */
  72 enum pwm_polarity {
  73         PWM_POLARITY_NORMAL,
  74         PWM_POLARITY_INVERSED,
  75 };
  76
  77 /**
  78  * struct pwm_args - board-dependent PWM arguments
  79  * @period: reference period
  80  * @polarity: reference polarity
  81  *
  82  * This structure describes board-dependent arguments attached to a PWM
  83  * device. These arguments are usually retrieved from the PWM lookup table or
  84  * device tree.
  85  *
  86  * Do not confuse this with the PWM state: PWM arguments represent the initial
  87  * configuration that users want to use on this PWM device rather than the
  88  * current PWM hardware state.
  89  */
  90 struct pwm_args {
  91         unsigned int period;
  92         enum pwm_polarity polarity;
  93 };
  94
  95 enum {
  96         PWMF_REQUESTED = 1 << 0,
  97         PWMF_ENABLED = 1 << 1,
  98         PWMF_EXPORTED = 1 << 2,
  99 };
 100
 101 /**
 102  * struct pwm_device - PWM channel object
 103  * @label: name of the PWM device
 104  * @flags: flags associated with the PWM device
 105  * @hwpwm: per-chip relative index of the PWM device
 106  * @pwm: global index of the PWM device
 107  * @chip: PWM chip providing this PWM device
 108  * @chip_data: chip-private data associated with the PWM device
 109  * @lock: used to serialize accesses to the PWM device where necessary
 110  * @period: period of the PWM signal (in nanoseconds)
 111  * @duty_cycle: duty cycle of the PWM signal (in nanoseconds)
 112  * @polarity: polarity of the PWM signal
 113  * @args: PWM arguments
 114  */
 115 struct pwm_device {
 116         const char *label;
 117         unsigned long flags;
 118         unsigned int hwpwm;
 119         unsigned int pwm;
 120         struct pwm_chip *chip;
 121         void *chip_data;
 122         struct mutex lock;
 123
 124         unsigned int period;
 125         unsigned int duty_cycle;
 126         enum pwm_polarity polarity;
 127
 128         struct pwm_args args;
 129 };
 130
 131 static inline bool pwm_is_enabled(const struct pwm_device *pwm)
 132 {
 133         return test_bit(PWMF_ENABLED, &pwm->flags);
 134 }
 135
 136 static inline void pwm_set_period(struct pwm_device *pwm, unsigned int period)
 137 {
 138         if (pwm)
 139                 pwm->period = period;
 140 }
 141
 142 static inline unsigned int pwm_get_period(const struct pwm_device *pwm)
 143 {
 144         return pwm ? pwm->period : 0;
 145 }
 146
 147 static inline void pwm_set_duty_cycle(struct pwm_device *pwm, unsigned int duty)
 148 {
 149         if (pwm)
 150                 pwm->duty_cycle = duty;
 151 }
 152
 153 static inline unsigned int pwm_get_duty_cycle(const struct pwm_device *pwm)
 154 {
 155         return pwm ? pwm->duty_cycle : 0;
 156 }
 157
 158 /*
 159  * pwm_set_polarity - configure the polarity of a PWM signal
 160  */
 161 int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity);
 162
 163 static inline enum pwm_polarity pwm_get_polarity(const struct pwm_device *pwm)
 164 {
 165         return pwm ? pwm->polarity : PWM_POLARITY_NORMAL;
 166 }
 167
 168 static inline void pwm_get_args(const struct pwm_device *pwm,
 169                                 struct pwm_args *args)
 170 {
 171         *args = pwm->args;
 172 }
 173
 174 static inline void pwm_apply_args(struct pwm_device *pwm)
 175 {
 176         pwm_set_period(pwm, pwm->args.period);
 177         pwm_set_polarity(pwm, pwm->args.polarity);
 178 }
 179
 180 /**
 181  * struct pwm_ops - PWM controller operations
 182  * @request: optional hook for requesting a PWM
 183  * @free: optional hook for freeing a PWM
 184  * @config: configure duty cycles and period length for this PWM
 185  * @set_polarity: configure the polarity of this PWM
 186  * @enable: enable PWM output toggling
 187  * @disable: disable PWM output toggling
 188  * @dbg_show: optional routine to show contents in debugfs
 189  * @owner: helps prevent removal of modules exporting active PWMs
 190  */
 191 struct pwm_ops {
 192         int (*request)(struct pwm_chip *chip, struct pwm_device *pwm);
 193         void (*free)(struct pwm_chip *chip, struct pwm_device *pwm);
 194         int (*config)(struct pwm_chip *chip, struct pwm_device *pwm,
 195                       int duty_ns, int period_ns);
 196         int (*set_polarity)(struct pwm_chip *chip, struct pwm_device *pwm,
 197                             enum pwm_polarity polarity);
 198         int (*enable)(struct pwm_chip *chip, struct pwm_device *pwm);
 199         void (*disable)(struct pwm_chip *chip, struct pwm_device *pwm);
 200 #ifdef CONFIG_DEBUG_FS
 201         void (*dbg_show)(struct pwm_chip *chip, struct seq_file *s);
 202 #endif
 203         struct module *owner;
 204 };
 205
 206 /**
 207  * struct pwm_chip - abstract a PWM controller
 208  * @dev: device providing the PWMs
 209  * @list: list node for internal use
 210  * @ops: callbacks for this PWM controller
 211  * @base: number of first PWM controlled by this chip
 212  * @npwm: number of PWMs controlled by this chip
 213  * @pwms: array of PWM devices allocated by the framework
 214  * @of_xlate: request a PWM device given a device tree PWM specifier
 215  * @of_pwm_n_cells: number of cells expected in the device tree PWM specifier
 216  * @can_sleep: must be true if the .config(), .enable() or .disable()
 217  *             operations may sleep
 218  */
 219 struct pwm_chip {
 220         struct device *dev;
 221         struct list_head list;
 222         const struct pwm_ops *ops;
 223         int base;
 224         unsigned int npwm;
 225
 226         struct pwm_device *pwms;
 227
 228         struct pwm_device * (*of_xlate)(struct pwm_chip *pc,
 229                                         const struct of_phandle_args *args);
 230         unsigned int of_pwm_n_cells;
 231         bool can_sleep;
 232 };
 233
 234 #if IS_ENABLED(CONFIG_PWM)
 235 int pwm_set_chip_data(struct pwm_device *pwm, void *data);
 236 void *pwm_get_chip_data(struct pwm_device *pwm);
 237
 238 int pwmchip_add_with_polarity(struct pwm_chip *chip,
 239                               enum pwm_polarity polarity);
 240 int pwmchip_add(struct pwm_chip *chip);
 241 int pwmchip_remove(struct pwm_chip *chip);
 242 struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
 243                                          unsigned int index,
 244                                          const char *label);
 245
 246 struct pwm_device *of_pwm_xlate_with_flags(struct pwm_chip *pc,
 247                 const struct of_phandle_args *args);
 248
 249 struct pwm_device *pwm_get(struct device *dev, const char *con_id);
 250 struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id);
 251 void pwm_put(struct pwm_device *pwm);
 252
 253 struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id);
 254 struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
 255                                    const char *con_id);
 256 void devm_pwm_put(struct device *dev, struct pwm_device *pwm);
 257
 258 bool pwm_can_sleep(struct pwm_device *pwm);
 259 #else
 260 static inline int pwm_set_chip_data(struct pwm_device *pwm, void *data)
 261 {
 262         return -EINVAL;
 263 }
 264
 265 static inline void *pwm_get_chip_data(struct pwm_device *pwm)
 266 {
 267         return NULL;
 268 }
 269
 270 static inline int pwmchip_add(struct pwm_chip *chip)
 271 {
 272         return -EINVAL;
 273 }
 274
 275 static inline int pwmchip_add_inversed(struct pwm_chip *chip)
 276 {
 277         return -EINVAL;
 278 }
 279
 280 static inline int pwmchip_remove(struct pwm_chip *chip)
 281 {
 282         return -EINVAL;
 283 }
 284
 285 static inline struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
 286                                                        unsigned int index,
 287                                                        const char *label)
 288 {
 289         return ERR_PTR(-ENODEV);
 290 }
 291
 292 static inline struct pwm_device *pwm_get(struct device *dev,
 293                                          const char *consumer)
 294 {
 295         return ERR_PTR(-ENODEV);
 296 }
 297
 298 static inline struct pwm_device *of_pwm_get(struct device_node *np,
 299                                             const char *con_id)
 300 {
 301         return ERR_PTR(-ENODEV);
 302 }
 303
 304 static inline void pwm_put(struct pwm_device *pwm)
 305 {
 306 }
 307
 308 static inline struct pwm_device *devm_pwm_get(struct device *dev,
 309                                               const char *consumer)
 310 {
 311         return ERR_PTR(-ENODEV);
 312 }
 313
 314 static inline struct pwm_device *devm_of_pwm_get(struct device *dev,
 315                                                  struct device_node *np,
 316                                                  const char *con_id)
 317 {
 318         return ERR_PTR(-ENODEV);
 319 }
 320
 321 static inline void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
 322 {
 323 }
 324
 325 static inline bool pwm_can_sleep(struct pwm_device *pwm)
 326 {
 327         return false;
 328 }
 329 #endif
 330
 331 struct pwm_lookup {
 332         struct list_head list;
 333         const char *provider;
 334         unsigned int index;
 335         const char *dev_id;
 336         const char *con_id;
 337         unsigned int period;
 338         enum pwm_polarity polarity;
 339 };
 340
 341 #define PWM_LOOKUP(_provider, _index, _dev_id, _con_id, _period, _polarity) \
 342         {                                               \
 343                 .provider = _provider,                  \
 344                 .index = _index,                        \
 345                 .dev_id = _dev_id,                      \
 346                 .con_id = _con_id,                      \
 347                 .period = _period,                      \
 348                 .polarity = _polarity                   \
 349         }
 350
 351 #if IS_ENABLED(CONFIG_PWM)
 352 void pwm_add_table(struct pwm_lookup *table, size_t num);
 353 void pwm_remove_table(struct pwm_lookup *table, size_t num);
 354 #else
 355 static inline void pwm_add_table(struct pwm_lookup *table, size_t num)
 356 {
 357 }
 358
 359 static inline void pwm_remove_table(struct pwm_lookup *table, size_t num)
 360 {
 361 }
 362 #endif
 363
 364 #ifdef CONFIG_PWM_SYSFS
 365 void pwmchip_sysfs_export(struct pwm_chip *chip);
 366 void pwmchip_sysfs_unexport(struct pwm_chip *chip);
 367 #else
 368 static inline void pwmchip_sysfs_export(struct pwm_chip *chip)
 369 {
 370 }
 371
 372 static inline void pwmchip_sysfs_unexport(struct pwm_chip *chip)
 373 {
 374 }
 375 #endif /* CONFIG_PWM_SYSFS */
 376
 377 #endif /* __LINUX_PWM_H */