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Message-ID: <825dbb02-5e76-45d1-acf6-78bcc2e999c8@linux.dev>
Date: Mon, 12 Jan 2026 11:37:51 +0000
From: Vadim Fedorenko <vadim.fedorenko@...ux.dev>
To: Ivan Vecera <ivecera@...hat.com>, netdev@...r.kernel.org
Cc: Donald Hunter <donald.hunter@...il.com>, Jakub Kicinski
<kuba@...nel.org>, "David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>, Paolo Abeni <pabeni@...hat.com>,
Simon Horman <horms@...nel.org>,
Arkadiusz Kubalewski <arkadiusz.kubalewski@...el.com>,
Jiri Pirko <jiri@...nulli.us>,
Prathosh Satish <Prathosh.Satish@...rochip.com>, Petr Oros
<poros@...hat.com>, linux-kernel@...r.kernel.org,
Michal Schmidt <mschmidt@...hat.com>
Subject: Re: [PATCH net-next 3/3] dpll: zl3073x: Implement device mode setting
support
On 12/01/2026 10:14, Ivan Vecera wrote:
> Add support for .supported_modes_get() and .mode_set() callbacks
> to enable switching between manual and automatic modes via netlink.
>
> Implement .supported_modes_get() to report available modes based
> on the current hardware configuration:
>
> * manual mode is always supported
> * automatic mode is supported unless the dpll channel is configured
> in NCO (Numerically Controlled Oscillator) mode
>
> Implement .mode_set() to handle the specific logic required when
> transitioning between modes:
>
> 1) Transition to manual:
> * If a valid reference is currently active, switch the hardware
> to ref-lock mode (force lock to that reference).
> * If no reference is valid and the DPLL is unlocked, switch to freerun.
> * Otherwise, switch to Holdover.
>
> 2) Transition to automatic:
> * If the currently selected reference pin was previously marked
> as non-selectable (likely during a previous manual forcing
> operation), restore its priority and selectability in the hardware.
> * Switch the hardware to Automatic selection mode.
>
> Signed-off-by: Ivan Vecera <ivecera@...hat.com>
> ---
> drivers/dpll/zl3073x/dpll.c | 106 ++++++++++++++++++++++++++++++++++++
> 1 file changed, 106 insertions(+)
>
> diff --git a/drivers/dpll/zl3073x/dpll.c b/drivers/dpll/zl3073x/dpll.c
> index 9879d85d29af0..d0a9c361dc1d8 100644
> --- a/drivers/dpll/zl3073x/dpll.c
> +++ b/drivers/dpll/zl3073x/dpll.c
> @@ -100,6 +100,20 @@ zl3073x_dpll_pin_direction_get(const struct dpll_pin *dpll_pin, void *pin_priv,
> return 0;
> }
>
> +static struct zl3073x_dpll_pin *
> +zl3073x_dpll_pin_get_by_ref(struct zl3073x_dpll *zldpll, u8 ref_id)
> +{
> + struct zl3073x_dpll_pin *pin;
> +
> + list_for_each_entry(pin, &zldpll->pins, list) {
> + if (zl3073x_dpll_is_input_pin(pin) &&
> + zl3073x_input_pin_ref_get(pin->id) == ref_id)
> + return pin;
> + }
> +
> + return NULL;
> +}
> +
> static int
> zl3073x_dpll_input_pin_esync_get(const struct dpll_pin *dpll_pin,
> void *pin_priv,
> @@ -1137,6 +1151,26 @@ zl3073x_dpll_lock_status_get(const struct dpll_device *dpll, void *dpll_priv,
> return 0;
> }
>
> +static int
> +zl3073x_dpll_supported_modes_get(const struct dpll_device *dpll,
> + void *dpll_priv, unsigned long *modes,
> + struct netlink_ext_ack *extack)
> +{
> + struct zl3073x_dpll *zldpll = dpll_priv;
> +
> + /* We support switching between automatic and manual mode, except in
> + * a case where the DPLL channel is configured to run in NCO mode.
> + * In this case, report only the manual mode to which the NCO is mapped
> + * as the only supported one.
> + */
> + if (zldpll->refsel_mode != ZL_DPLL_MODE_REFSEL_MODE_NCO)
> + __set_bit(DPLL_MODE_AUTOMATIC, modes);
> +
> + __set_bit(DPLL_MODE_MANUAL, modes);
> +
> + return 0;
> +}
> +
> static int
> zl3073x_dpll_mode_get(const struct dpll_device *dpll, void *dpll_priv,
> enum dpll_mode *mode, struct netlink_ext_ack *extack)
> @@ -1217,6 +1251,76 @@ zl3073x_dpll_phase_offset_avg_factor_set(const struct dpll_device *dpll,
> return 0;
> }
>
> +static int
> +zl3073x_dpll_mode_set(const struct dpll_device *dpll, void *dpll_priv,
> + enum dpll_mode mode, struct netlink_ext_ack *extack)
> +{
> + struct zl3073x_dpll *zldpll = dpll_priv;
> + u8 hw_mode, mode_refsel, ref;
> + int rc;
> +
> + rc = zl3073x_dpll_selected_ref_get(zldpll, &ref);
> + if (rc) {
> + NL_SET_ERR_MSG_MOD(extack, "failed to get selected reference");
> + return rc;
> + }
> +
> + if (mode == DPLL_MODE_MANUAL) {
> + /* We are switching from automatic to manual mode:
> + * - if we have a valid reference selected during auto mode then
> + * we will switch to forced reference lock mode and use this
> + * reference for selection
> + * - if NO valid reference is selected, we will switch to forced
> + * holdover mode or freerun mode, depending on the current
> + * lock status
> + */
> + if (ZL3073X_DPLL_REF_IS_VALID(ref))
> + hw_mode = ZL_DPLL_MODE_REFSEL_MODE_REFLOCK;
> + else if (zldpll->lock_status == DPLL_LOCK_STATUS_UNLOCKED)
> + hw_mode = ZL_DPLL_MODE_REFSEL_MODE_FREERUN;
> + else
> + hw_mode = ZL_DPLL_MODE_REFSEL_MODE_HOLDOVER;
> + } else {
> + /* We are switching from manual to automatic mode:
> + * - if there is a valid reference selected then ensure that
> + * it is selectable after switch to automatic mode
> + * - switch to automatic mode
> + */
> + struct zl3073x_dpll_pin *pin;
> +
> + pin = zl3073x_dpll_pin_get_by_ref(zldpll, ref);
> + if (pin && !pin->selectable) {
> + /* Restore pin priority in HW */
> + rc = zl3073x_dpll_ref_prio_set(pin, pin->prio);
> + if (rc)
> + return rc;
I think it's better to fill-up extack here to give at least some info of
what's happened?
> +
> + pin->selectable = true;
> + }
> +
> + hw_mode = ZL_DPLL_MODE_REFSEL_MODE_AUTO;
> + }
> +
> + /* Build mode_refsel value */
> + mode_refsel = FIELD_PREP(ZL_DPLL_MODE_REFSEL_MODE, hw_mode);
> +
> + if (ZL3073X_DPLL_REF_IS_VALID(ref))
> + mode_refsel |= FIELD_PREP(ZL_DPLL_MODE_REFSEL_REF, ref);
> +
> + /* Update dpll_mode_refsel register */
> + rc = zl3073x_write_u8(zldpll->dev, ZL_REG_DPLL_MODE_REFSEL(zldpll->id),
> + mode_refsel);
> + if (rc)
> + return rc;
And here as well..
> +
> + zldpll->refsel_mode = hw_mode;
> +
> + if (ZL3073X_DPLL_REF_IS_VALID(ref))
> + zldpll->forced_ref = ref;
> +
> + return 0;
> +}
> +
> static int
> zl3073x_dpll_phase_offset_monitor_get(const struct dpll_device *dpll,
> void *dpll_priv,
> @@ -1276,10 +1380,12 @@ static const struct dpll_pin_ops zl3073x_dpll_output_pin_ops = {
> static const struct dpll_device_ops zl3073x_dpll_device_ops = {
> .lock_status_get = zl3073x_dpll_lock_status_get,
> .mode_get = zl3073x_dpll_mode_get,
> + .mode_set = zl3073x_dpll_mode_set,
> .phase_offset_avg_factor_get = zl3073x_dpll_phase_offset_avg_factor_get,
> .phase_offset_avg_factor_set = zl3073x_dpll_phase_offset_avg_factor_set,
> .phase_offset_monitor_get = zl3073x_dpll_phase_offset_monitor_get,
> .phase_offset_monitor_set = zl3073x_dpll_phase_offset_monitor_set,
> + .supported_modes_get = zl3073x_dpll_supported_modes_get,
> };
>
> /**
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