linux-kernel - Re: [PATCH v5 07/11] clk: sunxi-ng: nkm: Support finding closest rate

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Message-ID: <23170854.6Emhk5qWAg@jernej-laptop>
Date:   Sun, 06 Aug 2023 15:42:13 +0200
From:   Jernej Škrabec <jernej.skrabec@...il.com>
To:     Maxime Ripard <mripard@...nel.org>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>, Chen-Yu Tsai <wens@...e.org>,
        Samuel Holland <samuel@...lland.org>,
        Andre Przywara <andre.przywara@....com>,
        Roman Beranek <me@...y.cz>, Frank Oltmanns <frank@...manns.dev>
Cc:     linux-clk@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-sunxi@...ts.linux.dev, linux-kernel@...r.kernel.org,
        Frank Oltmanns <frank@...manns.dev>
Subject: Re: [PATCH v5 07/11] clk: sunxi-ng: nkm: Support finding closest rate

Dne nedelja, 06. avgust 2023 ob 15:06:52 CEST je Frank Oltmanns napisal(a):
> When finding the best rate for a NKM clock, consider rates that are
> higher than the requested rate, if the CCU_FEATURE_CLOSEST_RATE flag is
> set by using the helper function ccu_is_better_rate().
> 
> Accommodate ccu_mux_helper_determine_rate to this change.
> 
> Acked-by: Maxime Ripard <mripard@...nel.org>
> Signed-off-by: Frank Oltmanns <frank@...manns.dev>

Reviewed-by: Jernej Skrabec <jernej.skrabec@...il.com>

Best regards,
Jernej

> ---
>  drivers/clk/sunxi-ng/ccu_mux.c |  2 +-
>  drivers/clk/sunxi-ng/ccu_nkm.c | 20 +++++++++-----------
>  2 files changed, 10 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/clk/sunxi-ng/ccu_mux.c b/drivers/clk/sunxi-ng/ccu_mux.c
> index 1d557e323169..3ca695439620 100644
> --- a/drivers/clk/sunxi-ng/ccu_mux.c
> +++ b/drivers/clk/sunxi-ng/ccu_mux.c
> @@ -139,7 +139,7 @@ int ccu_mux_helper_determine_rate(struct ccu_common
> *common, goto out;
>  		}
> 
> -		if ((req->rate - tmp_rate) < (req->rate - best_rate)) {
> +		if (ccu_is_better_rate(common, req->rate, tmp_rate, 
best_rate)) {
>  			best_rate = tmp_rate;
>  			best_parent_rate = parent_rate;
>  			best_parent = parent;
> diff --git a/drivers/clk/sunxi-ng/ccu_nkm.c b/drivers/clk/sunxi-ng/ccu_nkm.c
> index ea1b77e9b57f..896bb1ef8642 100644
> --- a/drivers/clk/sunxi-ng/ccu_nkm.c
> +++ b/drivers/clk/sunxi-ng/ccu_nkm.c
> @@ -17,7 +17,8 @@ struct _ccu_nkm {
>  	unsigned long	m, min_m, max_m;
>  };
> 
> -static unsigned long ccu_nkm_find_best_with_parent_adj(struct clk_hw
> *parent_hw, +static unsigned long ccu_nkm_find_best_with_parent_adj(struct
> ccu_common *common, +						
       struct clk_hw *parent_hw,
>  						       
unsigned long *parent, unsigned long rate,
>  						       
struct _ccu_nkm *nkm)
>  {
> @@ -33,10 +34,8 @@ static unsigned long
> ccu_nkm_find_best_with_parent_adj(struct clk_hw *parent_hw, tmp_parent =
> clk_hw_round_rate(parent_hw, rate * _m / (_n * _k));
> 
>  				tmp_rate = tmp_parent * _n * _k / 
_m;
> -				if (tmp_rate > rate)
> -					continue;
> 
> -				if ((rate - tmp_rate) < (rate - 
best_rate)) {
> +				if (ccu_is_better_rate(common, 
rate, tmp_rate, best_rate)) {
>  					best_rate = tmp_rate;
>  					best_parent_rate = 
tmp_parent;
>  					best_n = _n;
> @@ -57,7 +56,7 @@ static unsigned long
> ccu_nkm_find_best_with_parent_adj(struct clk_hw *parent_hw, }
> 
>  static unsigned long ccu_nkm_find_best(unsigned long parent, unsigned long
> rate, -				       struct _ccu_nkm *nkm)
> +				       struct _ccu_nkm *nkm, 
struct ccu_common *common)
>  {
>  	unsigned long best_rate = 0;
>  	unsigned long best_n = 0, best_k = 0, best_m = 0;
> @@ -70,9 +69,7 @@ static unsigned long ccu_nkm_find_best(unsigned long
> parent, unsigned long rate,
> 
>  				tmp_rate = parent * _n * _k / _m;
> 
> -				if (tmp_rate > rate)
> -					continue;
> -				if ((rate - tmp_rate) < (rate - 
best_rate)) {
> +				if (ccu_is_better_rate(common, 
rate, tmp_rate, best_rate)) {
>  					best_rate = tmp_rate;
>  					best_n = _n;
>  					best_k = _k;
> @@ -165,9 +162,10 @@ static unsigned long ccu_nkm_round_rate(struct
> ccu_mux_internal *mux, rate *= nkm->fixed_post_div;
> 
>  	if (!clk_hw_can_set_rate_parent(&nkm->common.hw))
> -		rate = ccu_nkm_find_best(*parent_rate, rate, &_nkm);
> +		rate = ccu_nkm_find_best(*parent_rate, rate, &_nkm, &nkm-
>common);
>  	else
> -		rate = ccu_nkm_find_best_with_parent_adj(parent_hw, 
parent_rate, rate,
> &_nkm); +		rate = ccu_nkm_find_best_with_parent_adj(&nkm->common,
> parent_hw, parent_rate, rate, +					
		 &_nkm);
> 
>  	if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
>  		rate /= nkm->fixed_post_div;
> @@ -202,7 +200,7 @@ static int ccu_nkm_set_rate(struct clk_hw *hw, unsigned
> long rate, _nkm.min_m = 1;
>  	_nkm.max_m = nkm->m.max ?: 1 << nkm->m.width;
> 
> -	ccu_nkm_find_best(parent_rate, rate, &_nkm);
> +	ccu_nkm_find_best(parent_rate, rate, &_nkm, &nkm->common);
> 
>  	spin_lock_irqsave(nkm->common.lock, flags);