Documentation/driver-api/dpll.rst

1 .. SPDX-License-Identifier: GPL-2.0
10 PLL - Phase Locked Loop is an electronic circuit which syntonizes clock
14 DPLL - Digital Phase Locked Loop is an integrated circuit which in
76 differences for each mode in terms of available pin states, as well as
77 for the states the user can request for a dpll device.
80 one of following pin states:
82 - ``DPLL_PIN_STATE_CONNECTED`` - the pin is used to drive dpll device
83 - ``DPLL_PIN_STATE_DISCONNECTED`` - the pin is not used to drive dpll
87 receive one of following pin states:
89 - ``DPLL_PIN_STATE_SELECTABLE`` - the pin shall be considered as valid
91 - ``DPLL_PIN_STATE_DISCONNECTED`` - the pin shall be not considered as
104 1) Set on a pin - the configuration affects all dpll devices pin is
106 2) Set on a pin-dpll tuple - the configuration affects only selected
110 MUX-type pins
113 A pin can be MUX-type, it aggregates child pins and serves as a pin
114 multiplexer. One or more pins are registered with MUX-type instead of
116 Pins registered with a MUX-type pin provide user with additional nested
121 ``DPLL_CMD_PIN_GET`` would contain multiple pin-parent nested
125           'clock-id': 282574471561216,
126           'module-name': 'ice',
129           'parent-pin': [
130           {'parent-id': 2, 'state': 'connected'},
131           {'parent-id': 3, 'state': 'disconnected'}
133           'type': 'synce-eth-port'
136 Only one child pin can provide its signal to the parent MUX-type pin at
171 Child pin of MUX-type pin is not capable of automatic input pin selection,
172 in order to configure active input of a MUX-type pin, the user needs to
174 as described in the ``MUX-type pins`` chapter.
180 on a pin and its parent dpll device. If pin-dpll phase offset measurement
213 offset values are fractional with 3-digit decimal places and shell be
221 to embed additional SYNC signal into the base frequency of a pin - a one
262                                        (EUI-64), as defined by the
273                                        (EUI-64), as defined by the
297                                        (EUI-64), as defined by the
314                                        (EUI-64), as defined by the
385 ``DPLL_CMD_DEVICE_SET`` - to target a dpll device, the user provides
389 ``DPLL_CMD_PIN_SET`` - to target a pin user must provide a
400 For MUX-type pins the ``DPLL_A_PIN_STATE`` attribute is configured in
408 Configuration pre-defined enums
411 .. kernel-doc:: include/uapi/linux/dpll.h
418 There is one multicast group that is used to notify user-space apps via
464 - dpll_pin_register() - register pin with a dpll device,
465 - dpll_pin_on_pin_register() - register pin with another MUX type pin.
474 - after successful change was requested on dpll subsystem, the subsystem
476 - requested by device driver with dpll_device_change_ntf() or
484 - ``.mode_get``,
485 - ``.lock_status_get``.
489 - ``.state_on_dpll_get`` (pins registered with dpll device),
490 - ``.state_on_pin_get`` (pins registered with parent pin),
491 - ``.direction_get``.
494 ``-EOPNOTSUPP`` is returned in case of absence of specific handler.
499 .. code-block:: c
517 .. code-block:: c
520         bp->dpll = dpll_device_get(clkid, 0, THIS_MODULE);
521         if (IS_ERR(bp->dpll)) {
522                 err = PTR_ERR(bp->dpll);
523                 dev_err(&pdev->dev, "dpll_device_alloc failed\n");
527         err = dpll_device_register(bp->dpll, DPLL_TYPE_PPS, &dpll_ops, bp);
532                 bp->sma[i].dpll_pin = dpll_pin_get(clkid, i, THIS_MODULE, &bp->sma[i].dpll_prop);
533                 if (IS_ERR(bp->sma[i].dpll_pin)) {
534                         err = PTR_ERR(bp->dpll);
538                 err = dpll_pin_register(bp->dpll, bp->sma[i].dpll_pin, &dpll_pins_ops,
539                                         &bp->sma[i]);
541                         dpll_pin_put(bp->sma[i].dpll_pin);
548 .. code-block:: c
551                 --i;
552                 dpll_pin_unregister(bp->dpll, bp->sma[i].dpll_pin, &dpll_pins_ops, &bp->sma[i]);
553                 dpll_pin_put(bp->sma[i].dpll_pin);
555         dpll_device_put(bp->dpll);
567 This is done by exposing a pin to the netdevice - attaching pin to the