linux-kernel - Re: [PATCH v5 10/11] clk: sunxi-ng: a64: select closest rate for pll-video0

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Message-ID: <2162023.Icojqenx9y@jernej-laptop>
Date:   Sun, 06 Aug 2023 15:48:08 +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 10/11] clk: sunxi-ng: a64: select closest rate for pll-video0

Dne nedelja, 06. avgust 2023 ob 15:06:55 CEST je Frank Oltmanns napisal(a):
> Selecting the closest rate for pll-video0 instead of the closest rate
> that is less than the requested rate has no downside for this clock,
> while allowing for selecting a more suitable rate, e.g. for the
> connected panels.
> 
> Furthermore, the algorithm that sets an NKM clock's parent benefits from
> the closest rate. Without it, the NKM clock's rate might drift away from
> the requested rate in the multiple successive calls to
> ccu_nkm_determine_rate that the clk framework performs when setting a
> clock rate.
> 
> Therefore, configure pll-video0 and, in consequence, all of its
> descendents to select the closest rate.
> 
> 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-sun50i-a64.c | 33
> ++++++++++++++------------------- 1 file changed, 14 insertions(+), 19
> deletions(-)
> 
> diff --git a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
> b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c index a139a5c438d4..73c84d20f3ee
> 100644
> --- a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
> +++ b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
> @@ -68,7 +68,7 @@ static SUNXI_CCU_NM_WITH_SDM_GATE_LOCK(pll_audio_base_clk,
> "pll-audio-base", BIT(28),	/* lock */
>  				       CLK_SET_RATE_UNGATE);
> 
> -static SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX(pll_video0_clk,
> "pll-video0", +static
> SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_CLOSEST(pll_video0_clk,
> "pll-video0", "osc24M", 0x010,
>  						192000000,	
/* Minimum rate */
>  						1008000000,	
/* Maximum rate */
> @@ -181,6 +181,7 @@ static struct ccu_nkm pll_mipi_clk = {
>  		.hw.init	= CLK_HW_INIT("pll-mipi", "pll-video0",
>  					      &ccu_nkm_ops,
>  					      
CLK_SET_RATE_UNGATE | CLK_SET_RATE_PARENT),
> +		.features	= CCU_FEATURE_CLOSEST_RATE,
>  	},
>  };
> 
> @@ -531,24 +532,18 @@ static SUNXI_CCU_M_WITH_MUX_GATE(de_clk, "de",
> de_parents,
> 
>  static const char * const tcon0_parents[] = { "pll-mipi", "pll-video0-2x"
> }; static const u8 tcon0_table[] = { 0, 2, };
> -static SUNXI_CCU_MUX_TABLE_WITH_GATE(tcon0_clk, "tcon0", tcon0_parents,
> +static SUNXI_CCU_MUX_TABLE_WITH_GATE_CLOSEST(tcon0_clk, "tcon0",
> tcon0_parents, tcon0_table, 0x118, 24, 3, BIT(31),
>  				     CLK_SET_RATE_PARENT);
> 
>  static const char * const tcon1_parents[] = { "pll-video0", "pll-video1" };
> static const u8 tcon1_table[] = { 0, 2, };
> -static struct ccu_div tcon1_clk = {
> -	.enable		= BIT(31),
> -	.div		= _SUNXI_CCU_DIV(0, 4),
> -	.mux		= _SUNXI_CCU_MUX_TABLE(24, 2, tcon1_table),
> -	.common		= {
> -		.reg		= 0x11c,
> -		.hw.init	= CLK_HW_INIT_PARENTS("tcon1",
> -						      
tcon1_parents,
> -						      
&ccu_div_ops,
> -						      
CLK_SET_RATE_PARENT),
> -	},
> -};
> +static SUNXI_CCU_M_WITH_MUX_TABLE_GATE_CLOSEST(tcon1_clk, "tcon1",
> tcon1_parents, +					       
tcon1_table, 0x11c,
> +					       0, 4,	/* M */
> +					       24, 2,	/* mux 
*/
> +					       BIT(31),	/* gate 
*/
> +					       
CLK_SET_RATE_PARENT);
> 
>  static const char * const deinterlace_parents[] = { "pll-periph0",
> "pll-periph1" }; static SUNXI_CCU_M_WITH_MUX_GATE(deinterlace_clk,
> "deinterlace", deinterlace_parents, @@ -578,8 +573,8 @@ static
> SUNXI_CCU_GATE(avs_clk,		"avs",		"osc24M", 
0x144, BIT(31), 0);
> 
>  static const char * const hdmi_parents[] = { "pll-video0", "pll-video1" };
> -static SUNXI_CCU_M_WITH_MUX_GATE(hdmi_clk, "hdmi", hdmi_parents,
> -				 0x150, 0, 4, 24, 2, BIT(31), 
CLK_SET_RATE_PARENT);
> +static SUNXI_CCU_M_WITH_MUX_GATE_CLOSEST(hdmi_clk, "hdmi", hdmi_parents,
> +					 0x150, 0, 4, 24, 2, 
BIT(31), CLK_SET_RATE_PARENT);
> 
>  static SUNXI_CCU_GATE(hdmi_ddc_clk,	"hdmi-ddc",	"osc24M",
>  		      0x154, BIT(31), 0);
> @@ -591,9 +586,9 @@ static SUNXI_CCU_M_WITH_MUX_GATE(mbus_clk, "mbus",
> mbus_parents,
> 
>  static const char * const dsi_dphy_parents[] = { "pll-video0",
> "pll-periph0" }; static const u8 dsi_dphy_table[] = { 0, 2, };
> -static SUNXI_CCU_M_WITH_MUX_TABLE_GATE(dsi_dphy_clk, "dsi-dphy",
> -				       dsi_dphy_parents, 
dsi_dphy_table,
> -				       0x168, 0, 4, 8, 2, 
BIT(15), CLK_SET_RATE_PARENT);
> +static SUNXI_CCU_M_WITH_MUX_TABLE_GATE_CLOSEST(dsi_dphy_clk, "dsi-dphy",
> +					       
dsi_dphy_parents, dsi_dphy_table,
> +					       0x168, 0, 4, 8, 
2, BIT(15), CLK_SET_RATE_PARENT);
> 
>  static SUNXI_CCU_M_WITH_GATE(gpu_clk, "gpu", "pll-gpu",
>  			     0x1a0, 0, 3, BIT(31), 
CLK_SET_RATE_PARENT);