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1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * PTP 1588 clock support
4 *
5 * Copyright (C) 2010 OMICRON electronics GmbH
6 */
7
8#ifndef _PTP_CLOCK_KERNEL_H_
9#define _PTP_CLOCK_KERNEL_H_
10
11#include <linux/device.h>
12#include <linux/pps_kernel.h>
13#include <linux/ptp_clock.h>
14
15/**
16 * struct ptp_clock_request - request PTP clock event
17 *
18 * @type: The type of the request.
19 * EXTTS: Configure external trigger timestamping
20 * PEROUT: Configure periodic output signal (e.g. PPS)
21 * PPS: trigger internal PPS event for input
22 * into kernel PPS subsystem
23 * @extts: describes configuration for external trigger timestamping.
24 * This is only valid when event == PTP_CLK_REQ_EXTTS.
25 * @perout: describes configuration for periodic output.
26 * This is only valid when event == PTP_CLK_REQ_PEROUT.
27 */
28
29struct ptp_clock_request {
30 enum {
31 PTP_CLK_REQ_EXTTS,
32 PTP_CLK_REQ_PEROUT,
33 PTP_CLK_REQ_PPS,
34 } type;
35 union {
36 struct ptp_extts_request extts;
37 struct ptp_perout_request perout;
38 };
39};
40
41struct system_device_crosststamp;
42
43/**
44 * struct ptp_system_timestamp - system time corresponding to a PHC timestamp
45 */
46struct ptp_system_timestamp {
47 struct timespec64 pre_ts;
48 struct timespec64 post_ts;
49};
50
51/**
52 * struct ptp_clock_info - describes a PTP hardware clock
53 *
54 * @owner: The clock driver should set to THIS_MODULE.
55 * @name: A short "friendly name" to identify the clock and to
56 * help distinguish PHY based devices from MAC based ones.
57 * The string is not meant to be a unique id.
58 * @max_adj: The maximum possible frequency adjustment, in parts per billon.
59 * @n_alarm: The number of programmable alarms.
60 * @n_ext_ts: The number of external time stamp channels.
61 * @n_per_out: The number of programmable periodic signals.
62 * @n_pins: The number of programmable pins.
63 * @pps: Indicates whether the clock supports a PPS callback.
64 * @pin_config: Array of length 'n_pins'. If the number of
65 * programmable pins is nonzero, then drivers must
66 * allocate and initialize this array.
67 *
68 * clock operations
69 *
70 * @adjfine: Adjusts the frequency of the hardware clock.
71 * parameter scaled_ppm: Desired frequency offset from
72 * nominal frequency in parts per million, but with a
73 * 16 bit binary fractional field.
74 *
75 * @adjfreq: Adjusts the frequency of the hardware clock.
76 * This method is deprecated. New drivers should implement
77 * the @adjfine method instead.
78 * parameter delta: Desired frequency offset from nominal frequency
79 * in parts per billion
80 *
81 * @adjphase: Adjusts the phase offset of the hardware clock.
82 * parameter delta: Desired change in nanoseconds.
83 *
84 * @adjtime: Shifts the time of the hardware clock.
85 * parameter delta: Desired change in nanoseconds.
86 *
87 * @gettime64: Reads the current time from the hardware clock.
88 * This method is deprecated. New drivers should implement
89 * the @gettimex64 method instead.
90 * parameter ts: Holds the result.
91 *
92 * @gettimex64: Reads the current time from the hardware clock and optionally
93 * also the system clock.
94 * parameter ts: Holds the PHC timestamp.
95 * parameter sts: If not NULL, it holds a pair of timestamps from
96 * the system clock. The first reading is made right before
97 * reading the lowest bits of the PHC timestamp and the second
98 * reading immediately follows that.
99 *
100 * @getcrosststamp: Reads the current time from the hardware clock and
101 * system clock simultaneously.
102 * parameter cts: Contains timestamp (device,system) pair,
103 * where system time is realtime and monotonic.
104 *
105 * @settime64: Set the current time on the hardware clock.
106 * parameter ts: Time value to set.
107 *
108 * @enable: Request driver to enable or disable an ancillary feature.
109 * parameter request: Desired resource to enable or disable.
110 * parameter on: Caller passes one to enable or zero to disable.
111 *
112 * @verify: Confirm that a pin can perform a given function. The PTP
113 * Hardware Clock subsystem maintains the 'pin_config'
114 * array on behalf of the drivers, but the PHC subsystem
115 * assumes that every pin can perform every function. This
116 * hook gives drivers a way of telling the core about
117 * limitations on specific pins. This function must return
118 * zero if the function can be assigned to this pin, and
119 * nonzero otherwise.
120 * parameter pin: index of the pin in question.
121 * parameter func: the desired function to use.
122 * parameter chan: the function channel index to use.
123 *
124 * @do_aux_work: Request driver to perform auxiliary (periodic) operations
125 * Driver should return delay of the next auxiliary work
126 * scheduling time (>=0) or negative value in case further
127 * scheduling is not required.
128 *
129 * Drivers should embed their ptp_clock_info within a private
130 * structure, obtaining a reference to it using container_of().
131 *
132 * The callbacks must all return zero on success, non-zero otherwise.
133 */
134
135struct ptp_clock_info {
136 struct module *owner;
137 char name[16];
138 s32 max_adj;
139 int n_alarm;
140 int n_ext_ts;
141 int n_per_out;
142 int n_pins;
143 int pps;
144 struct ptp_pin_desc *pin_config;
145 int (*adjfine)(struct ptp_clock_info *ptp, long scaled_ppm);
146 int (*adjfreq)(struct ptp_clock_info *ptp, s32 delta);
147 int (*adjphase)(struct ptp_clock_info *ptp, s32 phase);
148 int (*adjtime)(struct ptp_clock_info *ptp, s64 delta);
149 int (*gettime64)(struct ptp_clock_info *ptp, struct timespec64 *ts);
150 int (*gettimex64)(struct ptp_clock_info *ptp, struct timespec64 *ts,
151 struct ptp_system_timestamp *sts);
152 int (*getcrosststamp)(struct ptp_clock_info *ptp,
153 struct system_device_crosststamp *cts);
154 int (*settime64)(struct ptp_clock_info *p, const struct timespec64 *ts);
155 int (*enable)(struct ptp_clock_info *ptp,
156 struct ptp_clock_request *request, int on);
157 int (*verify)(struct ptp_clock_info *ptp, unsigned int pin,
158 enum ptp_pin_function func, unsigned int chan);
159 long (*do_aux_work)(struct ptp_clock_info *ptp);
160};
161
162struct ptp_clock;
163
164enum ptp_clock_events {
165 PTP_CLOCK_ALARM,
166 PTP_CLOCK_EXTTS,
167 PTP_CLOCK_PPS,
168 PTP_CLOCK_PPSUSR,
169};
170
171/**
172 * struct ptp_clock_event - decribes a PTP hardware clock event
173 *
174 * @type: One of the ptp_clock_events enumeration values.
175 * @index: Identifies the source of the event.
176 * @timestamp: When the event occurred (%PTP_CLOCK_EXTTS only).
177 * @pps_times: When the event occurred (%PTP_CLOCK_PPSUSR only).
178 */
179
180struct ptp_clock_event {
181 int type;
182 int index;
183 union {
184 u64 timestamp;
185 struct pps_event_time pps_times;
186 };
187};
188
189/**
190 * scaled_ppm_to_ppb() - convert scaled ppm to ppb
191 *
192 * @ppm: Parts per million, but with a 16 bit binary fractional field
193 */
194static inline long scaled_ppm_to_ppb(long ppm)
195{
196 /*
197 * The 'freq' field in the 'struct timex' is in parts per
198 * million, but with a 16 bit binary fractional field.
199 *
200 * We want to calculate
201 *
202 * ppb = scaled_ppm * 1000 / 2^16
203 *
204 * which simplifies to
205 *
206 * ppb = scaled_ppm * 125 / 2^13
207 */
208 s64 ppb = 1 + ppm;
209
210 ppb *= 125;
211 ppb >>= 13;
212 return (long)ppb;
213}
214
215#if IS_REACHABLE(CONFIG_PTP_1588_CLOCK)
216
217/**
218 * ptp_clock_register() - register a PTP hardware clock driver
219 *
220 * @info: Structure describing the new clock.
221 * @parent: Pointer to the parent device of the new clock.
222 *
223 * Returns a valid pointer on success or PTR_ERR on failure. If PHC
224 * support is missing at the configuration level, this function
225 * returns NULL, and drivers are expected to gracefully handle that
226 * case separately.
227 */
228
229extern struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
230 struct device *parent);
231
232/**
233 * ptp_clock_unregister() - unregister a PTP hardware clock driver
234 *
235 * @ptp: The clock to remove from service.
236 */
237
238extern int ptp_clock_unregister(struct ptp_clock *ptp);
239
240/**
241 * ptp_clock_event() - notify the PTP layer about an event
242 *
243 * @ptp: The clock obtained from ptp_clock_register().
244 * @event: Message structure describing the event.
245 */
246
247extern void ptp_clock_event(struct ptp_clock *ptp,
248 struct ptp_clock_event *event);
249
250/**
251 * ptp_clock_index() - obtain the device index of a PTP clock
252 *
253 * @ptp: The clock obtained from ptp_clock_register().
254 */
255
256extern int ptp_clock_index(struct ptp_clock *ptp);
257
258/**
259 * ptp_find_pin() - obtain the pin index of a given auxiliary function
260 *
261 * The caller must hold ptp_clock::pincfg_mux. Drivers do not have
262 * access to that mutex as ptp_clock is an opaque type. However, the
263 * core code acquires the mutex before invoking the driver's
264 * ptp_clock_info::enable() callback, and so drivers may call this
265 * function from that context.
266 *
267 * @ptp: The clock obtained from ptp_clock_register().
268 * @func: One of the ptp_pin_function enumerated values.
269 * @chan: The particular functional channel to find.
270 * Return: Pin index in the range of zero to ptp_clock_caps.n_pins - 1,
271 * or -1 if the auxiliary function cannot be found.
272 */
273
274int ptp_find_pin(struct ptp_clock *ptp,
275 enum ptp_pin_function func, unsigned int chan);
276
277/**
278 * ptp_find_pin_unlocked() - wrapper for ptp_find_pin()
279 *
280 * This function acquires the ptp_clock::pincfg_mux mutex before
281 * invoking ptp_find_pin(). Instead of using this function, drivers
282 * should most likely call ptp_find_pin() directly from their
283 * ptp_clock_info::enable() method.
284 *
285 */
286
287int ptp_find_pin_unlocked(struct ptp_clock *ptp,
288 enum ptp_pin_function func, unsigned int chan);
289
290/**
291 * ptp_schedule_worker() - schedule ptp auxiliary work
292 *
293 * @ptp: The clock obtained from ptp_clock_register().
294 * @delay: number of jiffies to wait before queuing
295 * See kthread_queue_delayed_work() for more info.
296 */
297
298int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay);
299
300/**
301 * ptp_cancel_worker_sync() - cancel ptp auxiliary clock
302 *
303 * @ptp: The clock obtained from ptp_clock_register().
304 */
305void ptp_cancel_worker_sync(struct ptp_clock *ptp);
306
307#else
308static inline struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
309 struct device *parent)
310{ return NULL; }
311static inline int ptp_clock_unregister(struct ptp_clock *ptp)
312{ return 0; }
313static inline void ptp_clock_event(struct ptp_clock *ptp,
314 struct ptp_clock_event *event)
315{ }
316static inline int ptp_clock_index(struct ptp_clock *ptp)
317{ return -1; }
318static inline int ptp_find_pin(struct ptp_clock *ptp,
319 enum ptp_pin_function func, unsigned int chan)
320{ return -1; }
321static inline int ptp_schedule_worker(struct ptp_clock *ptp,
322 unsigned long delay)
323{ return -EOPNOTSUPP; }
324static inline void ptp_cancel_worker_sync(struct ptp_clock *ptp)
325{ }
326
327#endif
328
329static inline void ptp_read_system_prets(struct ptp_system_timestamp *sts)
330{
331 if (sts)
332 ktime_get_real_ts64(&sts->pre_ts);
333}
334
335static inline void ptp_read_system_postts(struct ptp_system_timestamp *sts)
336{
337 if (sts)
338 ktime_get_real_ts64(&sts->post_ts);
339}
340
341#endif