[PATCH 01/13] clk: add new flag CLK_ROUNDING_FW_MANAGED

[Biju Das]

Hi Brain,

Thanks for the patch

> -----Original Message-----
> From: linux-arm-kernel <linux-arm-kernel-bounces at lists.infradead.org> On Behalf Of Brian Masney
> Sent: 26 February 2026 18:17
> Subject: [PATCH 01/13] clk: add new flag CLK_ROUNDING_FW_MANAGED
> 
> There are some clocks where the rounding is managed by the hardware, and the determine_rate() clk ops
> is just a noop that simply returns 0. Add a new flag for these type of clocks, and update the clk core
> so that the
> determine_rate() clk op is not required when this flag is set.
> 
> Signed-off-by: Brian Masney <bmasney at redhat.com>
> 
> ---
> To: Michael Turquette <mturquette at baylibre.com>
> To: Stephen Boyd <sboyd at kernel.org>
> To: Abel Vesa <abelvesa at kernel.org>
> To: Andrea della Porta <andrea.porta at suse.com>
> To: Baolin Wang <baolin.wang at linux.alibaba.com>
> To: Bjorn Andersson <andersson at kernel.org>
> To: Chanwoo Choi <cw00.choi at samsung.com>
> To: Frank Li <Frank.Li at nxp.com>
> To: Geert Uytterhoeven <geert+renesas at glider.be>
> To: Krzysztof Kozlowski <krzk at kernel.org>
> To: Orson Zhai <orsonzhai at gmail.com>
> To: Sascha Hauer <s.hauer at pengutronix.de>
> To: Sudeep Holla <sudeep.holla at kernel.org>
> To: Sylwester Nawrocki <s.nawrocki at samsung.com>
> To: Tudor Ambarus <tudor.ambarus at linaro.org>
> Cc: linux-clk at vger.kernel.org
> Cc: linux-kernel at vger.kernel.org
> Cc: Alim Akhtar <alim.akhtar at samsung.com>
> Cc: arm-scmi at vger.kernel.org
> Cc: Chunyan Zhang <zhang.lyra at gmail.com>
> Cc: Cristian Marussi <cristian.marussi at arm.com>
> Cc: Fabio Estevam <festevam at gmail.com>
> Cc: imx at lists.linux.dev
> Cc: linux-arm-kernel at lists.infradead.org
> Cc: linux-arm-msm at vger.kernel.org
> Cc: linux-renesas-soc at vger.kernel.org
> Cc: linux-samsung-soc at vger.kernel.org
> Cc: Peng Fan <peng.fan at nxp.com>
> Cc: Pengutronix Kernel Team <kernel at pengutronix.de>
> ---
>  drivers/clk/clk.c            | 24 +++++++++++++++++++++---
>  include/linux/clk-provider.h |  2 ++
>  2 files changed, 23 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index
> fd418dc988b1c60c49e3ac9c0c44aa132dd5da28..0a522a0817411c7f7c6e9cffd6f024e672a331a8 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -1557,6 +1557,20 @@ static int __init clk_disable_unused(void)  }
> late_initcall_sync(clk_disable_unused);
> 
> +/**
> + * clk_is_rounding_fw_managed - Check to see if clk rounding is handled
> +by the
> + * firmware.
> + * @core: the clk to check
> + *
> + * Clks that have this flag enabled do not need to have a
> +determine_rate() op
> + * set, and will always return success for any rounding operation since
> +the
> + * firmware will deal with the rounding.
> + */
> +static inline bool clk_is_rounding_fw_managed(struct clk_core *core) {
> +	return core->flags & CLK_ROUNDING_FW_MANAGED; }
> +
>  static int clk_core_determine_round_nolock(struct clk_core *core,
>  					   struct clk_rate_request *req)
>  {
> @@ -1589,6 +1603,8 @@ static int clk_core_determine_round_nolock(struct clk_core *core,
>  		req->rate = core->rate;
>  	} else if (core->ops->determine_rate) {
>  		return core->ops->determine_rate(core->hw, req);
> +	} else if (clk_is_rounding_fw_managed(core)) {
> +		return 0;
>  	} else {
>  		return -EINVAL;
>  	}
> @@ -1673,7 +1689,7 @@ EXPORT_SYMBOL_GPL(clk_hw_forward_rate_request);
> 
>  static bool clk_core_can_round(struct clk_core * const core)  {
> -	return core->ops->determine_rate;
> +	return core->ops->determine_rate || clk_is_rounding_fw_managed(core);
>  }
> 
>  static int clk_core_round_rate_nolock(struct clk_core *core, @@ -3528,6 +3544,7 @@ static const
> struct {
>  	ENTRY(CLK_IS_CRITICAL),
>  	ENTRY(CLK_OPS_PARENT_ENABLE),
>  	ENTRY(CLK_DUTY_CYCLE_PARENT),
> +	ENTRY(CLK_ROUNDING_FW_MANAGED),
>  #undef ENTRY
>  };
> 
> @@ -3906,7 +3923,7 @@ static int __clk_core_init(struct clk_core *core)
> 
>  	/* check that clk_ops are sane.  See Documentation/driver-api/clk.rst */
>  	if (core->ops->set_rate && !core->ops->determine_rate &&
> -	      core->ops->recalc_rate) {
> +	      core->ops->recalc_rate && !clk_is_rounding_fw_managed(core)) {
>  		pr_err("%s: %s must implement .determine_rate in addition to .recalc_rate\n",
>  		       __func__, core->name);
>  		ret = -EINVAL;
> @@ -3920,7 +3937,8 @@ static int __clk_core_init(struct clk_core *core)
>  		goto out;
>  	}
> 
> -	if (core->ops->set_parent && !core->ops->determine_rate) {
> +	if (core->ops->set_parent && !core->ops->determine_rate &&
> +	    !clk_is_rounding_fw_managed(core)) {

>  		pr_err("%s: %s must implement .set_parent & .determine_rate\n",
>  			__func__, core->name);
>  		ret = -EINVAL;


After applying patch#11, I get a message as you removed .determine_rate, Also it breaks display.

[    0.096414] __clk_core_init: .pll5_foutpostdiv must implement .round_rate or .determine_rate in addition to .recalc_rate


Cheers,
Biju