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From:   Jernej =?utf-8?B?xaBrcmFiZWM=?= <jernej.skrabec@gmail.com>
To:     Maxime Ripard <mripard@kernel.org>,
        Michael Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@kernel.org>, Chen-Yu Tsai <wens@csie.org>,
        Samuel Holland <samuel@sholland.org>,
        Andre Przywara <andre.przywara@arm.com>,
        Roman Beranek <me@crly.cz>, Frank Oltmanns <frank@oltmanns.dev>
Cc:     linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-sunxi@lists.linux.dev, linux-kernel@vger.kernel.org,
        Frank Oltmanns <frank@oltmanns.dev>
Subject: Re: [PATCH v5 06/11] clk: sunxi-ng: nm: Support finding closest rate
Date:   Sun, 06 Aug 2023 15:42:00 +0200
Message-ID: <3432648.QJadu78ljV@jernej-laptop>
In-Reply-To: <20230806-pll-mipi_set_rate_parent-v5-6-db4f5ca33fc3@oltmanns.dev>
References: <20230806-pll-mipi_set_rate_parent-v5-0-db4f5ca33fc3@oltmanns.dev>
 <20230806-pll-mipi_set_rate_parent-v5-6-db4f5ca33fc3@oltmanns.dev>
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Precedence: bulk

Dne nedelja, 06. avgust 2023 ob 15:06:51 CEST je Frank Oltmanns napisal(a):
> Use the helper function ccu_is_better_rate() to determine the rate that
> is closest to the requested rate, thereby supporting rates that are
> higher than the requested rate if the clock uses the
> CCU_FEATURE_CLOSEST_RATE.
> 
> Add the macro SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_CLOSEST which
> sets CCU_FEATURE_CLOSEST_RATE.
> 
> To avoid code duplication, add the macros
> SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_FEAT that allows selecting
> arbitrary features and use it in the original
> SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX as well as the newly introduced
> SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_CLOSEST macros.
> 
> Acked-by: Maxime Ripard <mripard@kernel.org>
> Signed-off-by: Frank Oltmanns <frank@oltmanns.dev>

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

Best regards,
Jernej

> ---
>  drivers/clk/sunxi-ng/ccu_nm.c | 13 +++++-------
>  drivers/clk/sunxi-ng/ccu_nm.h | 48
> ++++++++++++++++++++++++++++++++++++++++--- 2 files changed, 50
> insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/clk/sunxi-ng/ccu_nm.c b/drivers/clk/sunxi-ng/ccu_nm.c
> index c1fd11542c45..ffac3deb89d6 100644
> --- a/drivers/clk/sunxi-ng/ccu_nm.c
> +++ b/drivers/clk/sunxi-ng/ccu_nm.c
> @@ -27,8 +27,8 @@ static unsigned long ccu_nm_calc_rate(unsigned long
> parent, return rate;
>  }
> 
> -static unsigned long ccu_nm_find_best(unsigned long parent, unsigned long
> rate, -				      struct _ccu_nm *nm)
> +static unsigned long ccu_nm_find_best(struct ccu_common *common, unsigned
> long parent, +				      unsigned long 
rate, struct _ccu_nm *nm)
>  {
>  	unsigned long best_rate = 0;
>  	unsigned long best_n = 0, best_m = 0;
> @@ -39,10 +39,7 @@ static unsigned long ccu_nm_find_best(unsigned long
> parent, unsigned long rate, unsigned long tmp_rate =
> ccu_nm_calc_rate(parent,
>  								
  _n, _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_m = _m;
> @@ -159,7 +156,7 @@ static long ccu_nm_round_rate(struct clk_hw *hw,
> unsigned long rate, _nm.min_m = 1;
>  	_nm.max_m = nm->m.max ?: 1 << nm->m.width;
> 
> -	rate = ccu_nm_find_best(*parent_rate, rate, &_nm);
> +	rate = ccu_nm_find_best(&nm->common, *parent_rate, rate, &_nm);
> 
>  	if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
>  		rate /= nm->fixed_post_div;
> @@ -210,7 +207,7 @@ static int ccu_nm_set_rate(struct clk_hw *hw, unsigned
> long rate, &_nm.m, &_nm.n);
>  	} else {
>  		ccu_sdm_helper_disable(&nm->common, &nm->sdm);
> -		ccu_nm_find_best(parent_rate, rate, &_nm);
> +		ccu_nm_find_best(&nm->common, parent_rate, rate, &_nm);
>  	}
> 
>  	spin_lock_irqsave(nm->common.lock, flags);
> diff --git a/drivers/clk/sunxi-ng/ccu_nm.h b/drivers/clk/sunxi-ng/ccu_nm.h
> index 2904e67f05a8..93c11693574f 100644
> --- a/drivers/clk/sunxi-ng/ccu_nm.h
> +++ b/drivers/clk/sunxi-ng/ccu_nm.h
> @@ -108,7 +108,7 @@ struct ccu_nm {
>  		},					
		\
>  	}
> 
> -#define SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX(_struct, _name,	\
> +#define SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_FEAT(_struct, _name,	\
>  						 _parent, 
_reg,		\
>  						 _min_rate, 
_max_rate,	\
>  						 _nshift, 
_nwidth,	\
> @@ -116,7 +116,8 @@ struct ccu_nm {
>  						 _frac_en, 
_frac_sel,	\
>  						 
_frac_rate_0,		\
>  						 
_frac_rate_1,		\
> -						 _gate, 
_lock, _flags)	\
> +						 _gate, 
_lock, _flags,	\
> +						 _features)	
	\
>  	struct ccu_nm _struct = {					
\
>  		.enable		= _gate,			
	\
>  		.lock		= _lock,			
	\
> @@ -129,7 +130,7 @@ struct ccu_nm {
>  		.max_rate	= _max_rate,				
\
>  		.common		= {				
	\
>  			.reg		= _reg,		
		\
> -			.features	= CCU_FEATURE_FRACTIONAL,	
\
> +			.features	= _features,			
\
>  			.hw.init	= CLK_HW_INIT(_name,		
\
>  						      
_parent,		\
>  						      
&ccu_nm_ops,	\
> @@ -137,6 +138,47 @@ struct ccu_nm {
>  		},					
		\
>  	}
> 
> +#define SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX(_struct, _name,	\
> +						 _parent, 
_reg,		\
> +						 _min_rate, 
_max_rate,	\
> +						 _nshift, 
_nwidth,	\
> +						 _mshift, 
_mwidth,	\
> +						 _frac_en, 
_frac_sel,	\
> +						 
_frac_rate_0,		\
> +						 
_frac_rate_1,		\
> +						 _gate, 
_lock, _flags)	\
> +	SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_FEAT(_struct, _name,	\
> +						_parent, 
_reg,		\
> +						_min_rate, 
_max_rate,	\
> +						_nshift, 
_nwidth,	\
> +						_mshift, 
_mwidth,	\
> +						_frac_en, 
_frac_sel,	\
> +						
_frac_rate_0,		\
> +						
_frac_rate_1,		\
> +						_gate, 
_lock, _flags,	\
> +						
CCU_FEATURE_FRACTIONAL)
> +
> +#define SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_CLOSEST(_struct, _name, \
> +						 _parent, 
_reg,		\
> +						 _min_rate, 
_max_rate,	\
> +						 _nshift, 
_nwidth,	\
> +						 _mshift, 
_mwidth,	\
> +						 _frac_en, 
_frac_sel,	\
> +						 
_frac_rate_0,		\
> +						 
_frac_rate_1,		\
> +						 _gate, 
_lock, _flags)	\
> +	SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_FEAT(_struct, _name,	\
> +						_parent, 
_reg,		\
> +						_min_rate, 
_max_rate,	\
> +						_nshift, 
_nwidth,	\
> +						_mshift, 
_mwidth,	\
> +						_frac_en, 
_frac_sel,	\
> +						
_frac_rate_0,		\
> +						
_frac_rate_1,		\
> +						_gate, 
_lock, _flags,	\
> +						
CCU_FEATURE_FRACTIONAL |\
> +						
CCU_FEATURE_CLOSEST_RATE)
> +
>  #define SUNXI_CCU_NM_WITH_GATE_LOCK(_struct, _name, _parent, _reg,	\
>  				    _nshift, _nwidth,		
	\
>  				    _mshift, _mwidth,		
	\