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_state - state of a PWM channel
 103  * @period: PWM period (in nanoseconds)
 104  * @duty_cycle: PWM duty cycle (in nanoseconds)
 105  * @polarity: PWM polarity
 106  */
 107 struct pwm_state {
 108         unsigned int period;
 109         unsigned int duty_cycle;
 110         enum pwm_polarity polarity;
 111 };
 112
 113 /**
 114  * struct pwm_device - PWM channel object
 115  * @label: name of the PWM device
 116  * @flags: flags associated with the PWM device
 117  * @hwpwm: per-chip relative index of the PWM device
 118  * @pwm: global index of the PWM device
 119  * @chip: PWM chip providing this PWM device
 120  * @chip_data: chip-private data associated with the PWM device
 121  * @args: PWM arguments
 122  * @state: curent PWM channel state
 123  */
 124 struct pwm_device {
 125         const char *label;
 126         unsigned long flags;
 127         unsigned int hwpwm;
 128         unsigned int pwm;
 129         struct pwm_chip *chip;
 130         void *chip_data;
 131
 132         struct pwm_args args;
 133         struct pwm_state state;
 134 };
 135
 136 /**
 137  * pwm_get_state() - retrieve the current PWM state
 138  * @pwm: PWM device
 139  * @state: state to fill with the current PWM state
 140  */
 141 static inline void pwm_get_state(const struct pwm_device *pwm,
 142                                  struct pwm_state *state)
 143 {
 144         *state = pwm->state;
 145 }
 146
 147 static inline bool pwm_is_enabled(const struct pwm_device *pwm)
 148 {
 149         return test_bit(PWMF_ENABLED, &pwm->flags);
 150 }
 151
 152 static inline void pwm_set_period(struct pwm_device *pwm, unsigned int period)
 153 {
 154         if (pwm)
 155                 pwm->state.period = period;
 156 }
 157
 158 static inline unsigned int pwm_get_period(const struct pwm_device *pwm)
 159 {
 160         struct pwm_state state;
 161
 162         pwm_get_state(pwm, &state);
 163
 164         return state.period;
 165 }
 166
 167 static inline void pwm_set_duty_cycle(struct pwm_device *pwm, unsigned int duty)
 168 {
 169         if (pwm)
 170                 pwm->state.duty_cycle = duty;
 171 }
 172
 173 static inline unsigned int pwm_get_duty_cycle(const struct pwm_device *pwm)
 174 {
 175         struct pwm_state state;
 176
 177         pwm_get_state(pwm, &state);
 178
 179         return state.duty_cycle;
 180 }
 181
 182 /*
 183  * pwm_set_polarity - configure the polarity of a PWM signal
 184  */
 185 int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity);
 186
 187 static inline enum pwm_polarity pwm_get_polarity(const struct pwm_device *pwm)
 188 {
 189         struct pwm_state state;
 190
 191         pwm_get_state(pwm, &state);
 192
 193         return state.polarity;
 194 }
 195
 196 static inline void pwm_get_args(const struct pwm_device *pwm,
 197                                 struct pwm_args *args)
 198 {
 199         *args = pwm->args;
 200 }
 201
 202 static inline void pwm_apply_args(struct pwm_device *pwm)
 203 {
 204         pwm_set_polarity(pwm, pwm->args.polarity);
 205 }
 206
 207 /**
 208  * struct pwm_ops - PWM controller operations
 209  * @request: optional hook for requesting a PWM
 210  * @free: optional hook for freeing a PWM
 211  * @config: configure duty cycles and period length for this PWM
 212  * @set_polarity: configure the polarity of this PWM
 213  * @enable: enable PWM output toggling
 214  * @disable: disable PWM output toggling
 215  * @dbg_show: optional routine to show contents in debugfs
 216  * @owner: helps prevent removal of modules exporting active PWMs
 217  */
 218 struct pwm_ops {
 219         int (*request)(struct pwm_chip *chip, struct pwm_device *pwm);
 220         void (*free)(struct pwm_chip *chip, struct pwm_device *pwm);
 221         int (*config)(struct pwm_chip *chip, struct pwm_device *pwm,
 222                       int duty_ns, int period_ns);
 223         int (*set_polarity)(struct pwm_chip *chip, struct pwm_device *pwm,
 224                             enum pwm_polarity polarity);
 225         int (*enable)(struct pwm_chip *chip, struct pwm_device *pwm);
 226         void (*disable)(struct pwm_chip *chip, struct pwm_device *pwm);
 227 #ifdef CONFIG_DEBUG_FS
 228         void (*dbg_show)(struct pwm_chip *chip, struct seq_file *s);
 229 #endif
 230         struct module *owner;
 231 };
 232
 233 /**
 234  * struct pwm_chip - abstract a PWM controller
 235  * @dev: device providing the PWMs
 236  * @list: list node for internal use
 237  * @ops: callbacks for this PWM controller
 238  * @base: number of first PWM controlled by this chip
 239  * @npwm: number of PWMs controlled by this chip
 240  * @pwms: array of PWM devices allocated by the framework
 241  * @of_xlate: request a PWM device given a device tree PWM specifier
 242  * @of_pwm_n_cells: number of cells expected in the device tree PWM specifier
 243  * @can_sleep: must be true if the .config(), .enable() or .disable()
 244  *             operations may sleep
 245  */
 246 struct pwm_chip {
 247         struct device *dev;
 248         struct list_head list;
 249         const struct pwm_ops *ops;
 250         int base;
 251         unsigned int npwm;
 252
 253         struct pwm_device *pwms;
 254
 255         struct pwm_device * (*of_xlate)(struct pwm_chip *pc,
 256                                         const struct of_phandle_args *args);
 257         unsigned int of_pwm_n_cells;
 258         bool can_sleep;
 259 };
 260
 261 #if IS_ENABLED(CONFIG_PWM)
 262 int pwm_set_chip_data(struct pwm_device *pwm, void *data);
 263 void *pwm_get_chip_data(struct pwm_device *pwm);
 264
 265 int pwmchip_add_with_polarity(struct pwm_chip *chip,
 266                               enum pwm_polarity polarity);
 267 int pwmchip_add(struct pwm_chip *chip);
 268 int pwmchip_remove(struct pwm_chip *chip);
 269 struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
 270                                          unsigned int index,
 271                                          const char *label);
 272
 273 struct pwm_device *of_pwm_xlate_with_flags(struct pwm_chip *pc,
 274                 const struct of_phandle_args *args);
 275
 276 struct pwm_device *pwm_get(struct device *dev, const char *con_id);
 277 struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id);
 278 void pwm_put(struct pwm_device *pwm);
 279
 280 struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id);
 281 struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
 282                                    const char *con_id);
 283 void devm_pwm_put(struct device *dev, struct pwm_device *pwm);
 284
 285 bool pwm_can_sleep(struct pwm_device *pwm);
 286 #else
 287 static inline int pwm_set_chip_data(struct pwm_device *pwm, void *data)
 288 {
 289         return -EINVAL;
 290 }
 291
 292 static inline void *pwm_get_chip_data(struct pwm_device *pwm)
 293 {
 294         return NULL;
 295 }
 296
 297 static inline int pwmchip_add(struct pwm_chip *chip)
 298 {
 299         return -EINVAL;
 300 }
 301
 302 static inline int pwmchip_add_inversed(struct pwm_chip *chip)
 303 {
 304         return -EINVAL;
 305 }
 306
 307 static inline int pwmchip_remove(struct pwm_chip *chip)
 308 {
 309         return -EINVAL;
 310 }
 311
 312 static inline struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
 313                                                        unsigned int index,
 314                                                        const char *label)
 315 {
 316         return ERR_PTR(-ENODEV);
 317 }
 318
 319 static inline struct pwm_device *pwm_get(struct device *dev,
 320                                          const char *consumer)
 321 {
 322         return ERR_PTR(-ENODEV);
 323 }
 324
 325 static inline struct pwm_device *of_pwm_get(struct device_node *np,
 326                                             const char *con_id)
 327 {
 328         return ERR_PTR(-ENODEV);
 329 }
 330
 331 static inline void pwm_put(struct pwm_device *pwm)
 332 {
 333 }
 334
 335 static inline struct pwm_device *devm_pwm_get(struct device *dev,
 336                                               const char *consumer)
 337 {
 338         return ERR_PTR(-ENODEV);
 339 }
 340
 341 static inline struct pwm_device *devm_of_pwm_get(struct device *dev,
 342                                                  struct device_node *np,
 343                                                  const char *con_id)
 344 {
 345         return ERR_PTR(-ENODEV);
 346 }
 347
 348 static inline void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
 349 {
 350 }
 351
 352 static inline bool pwm_can_sleep(struct pwm_device *pwm)
 353 {
 354         return false;
 355 }
 356 #endif
 357
 358 struct pwm_lookup {
 359         struct list_head list;
 360         const char *provider;
 361         unsigned int index;
 362         const char *dev_id;
 363         const char *con_id;
 364         unsigned int period;
 365         enum pwm_polarity polarity;
 366 };
 367
 368 #define PWM_LOOKUP(_provider, _index, _dev_id, _con_id, _period, _polarity) \
 369         {                                               \
 370                 .provider = _provider,                  \
 371                 .index = _index,                        \
 372                 .dev_id = _dev_id,                      \
 373                 .con_id = _con_id,                      \
 374                 .period = _period,                      \
 375                 .polarity = _polarity                   \
 376         }
 377
 378 #if IS_ENABLED(CONFIG_PWM)
 379 void pwm_add_table(struct pwm_lookup *table, size_t num);
 380 void pwm_remove_table(struct pwm_lookup *table, size_t num);
 381 #else
 382 static inline void pwm_add_table(struct pwm_lookup *table, size_t num)
 383 {
 384 }
 385
 386 static inline void pwm_remove_table(struct pwm_lookup *table, size_t num)
 387 {
 388 }
 389 #endif
 390
 391 #ifdef CONFIG_PWM_SYSFS
 392 void pwmchip_sysfs_export(struct pwm_chip *chip);
 393 void pwmchip_sysfs_unexport(struct pwm_chip *chip);
 394 #else
 395 static inline void pwmchip_sysfs_export(struct pwm_chip *chip)
 396 {
 397 }
 398
 399 static inline void pwmchip_sysfs_unexport(struct pwm_chip *chip)
 400 {
 401 }
 402 #endif /* CONFIG_PWM_SYSFS */
 403
 404 #endif /* __LINUX_PWM_H */