Re: [PATCH v2 2/5] clk: scmi: Add support for state control restricted clocks

Stephen Boyd
2024-04-08T04:49:01Z

Quoting Cristian Marussi (2024-03-25 14:00:22)
> Some exposed SCMI Clocks could be marked as non-supporting state changes.
> Configure a clk_ops descriptor which does not provide the state change
> callbacks for such clocks when registering with CLK framework.
>
> CC: Michael Turquette <mturquette@baylibre.com>
> CC: Stephen Boyd <sboyd@kernel.org>
> CC: linux-clk@vger.kernel.org
> Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
> ---
> drivers/clk/clk-scmi.c | 22 +++++++++++++++-------
> 1 file changed, 15 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/clk/clk-scmi.c b/drivers/clk/clk-scmi.c
> index d5d369b052bd..fc9603988d91 100644
> --- a/drivers/clk/clk-scmi.c
> +++ b/drivers/clk/clk-scmi.c
> @@ -18,6 +18,7 @@
>
> enum scmi_clk_feats {
> SCMI_CLK_ATOMIC_SUPPORTED,
> + SCMI_CLK_STATE_CTRL_FORBIDDEN,

Can it be positive, i.e. SCMI_CLK_STATE_CTRL_SUPPORTED?

> SCMI_CLK_MAX_FEATS
> };
>
> @@ -230,15 +231,19 @@ scmi_clk_ops_alloc(struct device *dev, unsigned long feats_key)
> * only the prepare/unprepare API, as allowed by the clock framework
> * when atomic calls are not available.
> */
> - if (feats_key & BIT(SCMI_CLK_ATOMIC_SUPPORTED)) {
> - ops->enable = scmi_clk_atomic_enable;
> - ops->disable = scmi_clk_atomic_disable;
> - ops->is_enabled = scmi_clk_atomic_is_enabled;
> - } else {
> - ops->prepare = scmi_clk_enable;
> - ops->unprepare = scmi_clk_disable;
> + if (!(feats_key & BIT(SCMI_CLK_STATE_CTRL_FORBIDDEN))) {
> + if (feats_key & BIT(SCMI_CLK_ATOMIC_SUPPORTED)) {
> + ops->enable = scmi_clk_atomic_enable;
> + ops->disable = scmi_clk_atomic_disable;
> + } else {
> + ops->prepare = scmi_clk_enable;
> + ops->unprepare = scmi_clk_disable;
> + }
> }
>
> + if (feats_key & BIT(SCMI_CLK_ATOMIC_SUPPORTED))
> + ops->is_enabled = scmi_clk_atomic_is_enabled;
> +
> /* Rate ops */
> ops->recalc_rate = scmi_clk_recalc_rate;
> ops->round_rate = scmi_clk_round_rate;
> @@ -288,6 +293,9 @@ scmi_clk_ops_select(struct scmi_clk *sclk, bool atomic_capable,
> if (atomic_capable && ci->enable_latency <= atomic_threshold)
> feats_key |= BIT(SCMI_CLK_ATOMIC_SUPPORTED);
>
> + if (ci->state_ctrl_forbidden)

Then this is negated.

> + feats_key |= BIT(SCMI_CLK_STATE_CTRL_FORBIDDEN);
> +
> /* Lookup previously allocated ops */
> ops = clk_ops_db[feats_key];