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Date:   Mon, 10 Jul 2023 10:23:53 +0200
From:   Jiri Pirko <jiri@resnulli.us>
To:     "Kubalewski, Arkadiusz" <arkadiusz.kubalewski@intel.com>
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Subject: Re: [RFC PATCH v8 08/10] ice: implement dpll interface to control cgu
Message-ID: <ZKvAGSwbJWEQmESs@nanopsycho>
References: <20230609121853.3607724-1-arkadiusz.kubalewski@intel.com>
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Precedence: bulk

Mon, Jul 03, 2023 at 02:37:18PM CEST, arkadiusz.kubalewski@intel.com wrote:
>>From: Jiri Pirko <jiri@resnulli.us>
>>Sent: Thursday, June 29, 2023 8:14 AM
>>
>>Wed, Jun 21, 2023 at 02:29:59PM CEST, jiri@resnulli.us wrote:
>>>Mon, Jun 19, 2023 at 10:34:12PM CEST, arkadiusz.kubalewski@intel.com
>>wrote:
>>>>>From: Jiri Pirko <jiri@resnulli.us>
>>>>>Sent: Saturday, June 10, 2023 6:37 PM
>>>>>
>>>>>Fri, Jun 09, 2023 at 02:18:51PM CEST, arkadiusz.kubalewski@intel.com
>>>>>wrote:
>>>>>
>>>>>[...]
>>>>>
>>>>>
>>>>>>+static int ice_dpll_mode_get(const struct dpll_device *dpll, void *priv,
>>>>>>+			     enum dpll_mode *mode,
>>>>>>+			     struct netlink_ext_ack *extack)
>>>>>>+{
>>>>>>+	*mode = DPLL_MODE_AUTOMATIC;
>>>>>
>>>>>I don't understand how the automatic mode could work with SyncE. The
>>>>>There is one pin exposed for one netdev. The SyncE daemon should select
>>>>>exacly one pin. How do you achieve that?
>>>>>Is is by setting DPLL_PIN_STATE_SELECTABLE on the pin-netdev you want to
>>>>>select and DPLL_PIN_STATE_DISCONNECTED on the rest?
>>>>>
>>>>>
>>>>>[...]
>>>>
>>>>AUTOMATIC mode autoselects highest priority valid signal.
>>>>As you have pointed out, for SyncE selection, the user must be able to
>>>>manually
>>>>select a pin state to enable recovery of signal from particular port.
>>>>
>>>>In "ice" case there are 2 pins for network PHY clock signal recovery, and
>>>>both
>>>>are parent pins (MUX-type). There are also 4 pins assigned to netdevs
>>>>(one per
>>>>port). Thus passing a signal from PHY to the pin is done through the MUX-
>>>>pin,
>>>>by selecting proper state on pin-parent pair (where parent pins is highest
>>>>prio
>>>>pin on dpll).
>>>
>>>Could you show me some examples please?
>>
>>Arkadiusz, could you please reply to this?
>>Thanks!
>>
>
>Sure, sorry for the delays, let's try that.
>
>'ice' use case:
>Enabling a PHY clock recovery for DPLL_MODE_AUTOMATIC dpll (ID#0) with PHY
>recovered clock signals (PIN_ID#13) being muxed using MUX-type pin (PIN_ID#2)
>
>1. Set MUX-type pin to state selectable and highest priority on a dpll device
>(or make sure it is already configured):
>CMD_PIN_SET:
>	PIN_ID			2
>	PIN_PARENT_DEVICE	(nest)
>		ID		0
>		PIN_STATE	SELECTABLE
>		PIN_PRIO	0
>(assume all the other pins have prio >=1)
>
>2. Set connected state on a pin-parent_pin tuple where parent is a pin from #1
>CMD_PIN_SET:
>	PIN_ID			13
>	PIN_PARENT_PIN		(nest)
>		PIN_ID		2
>		PIN_STATE	CONNECTED

How does this look from the perspective of a SyncE flow. Let's say you
have eth0 and eth1, both is connected with a DPLL pin. Could you show
how you select eth0 and then eth1?


>
>Thank you!
>Arkadiusz
>
>>>
>>>
>>>>
>>>>Thank you!
>>>>Arkadiusz