linux-kernel - Re: [PATCH v4 1/5] clk: sunxi-ng: common: Support minimum and maximum rate

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Date: Wed, 13 Mar 2024 19:17:43 +0100
From: Jernej Škrabec <jernej.skrabec@...il.com>
To: Michael Turquette <mturquette@...libre.com>,
 Stephen Boyd <sboyd@...nel.org>, Chen-Yu Tsai <wens@...e.org>,
 Samuel Holland <samuel@...lland.org>,
 Guido Günther <agx@...xcpu.org>,
 Purism Kernel Team <kernel@...i.sm>, Ondrej Jirman <megi@....cz>,
 Neil Armstrong <neil.armstrong@...aro.org>,
 Jessica Zhang <quic_jesszhan@...cinc.com>, Sam Ravnborg <sam@...nborg.org>,
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>,
 David Airlie <airlied@...il.com>, Daniel Vetter <daniel@...ll.ch>,
 Rob Herring <robh+dt@...nel.org>,
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
 Conor Dooley <conor+dt@...nel.org>, 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,
 dri-devel@...ts.freedesktop.org, devicetree@...r.kernel.org,
 Frank Oltmanns <frank@...manns.dev>, stable@...r.kernel.org
Subject:
 Re: [PATCH v4 1/5] clk: sunxi-ng: common: Support minimum and maximum rate

Dne nedelja, 10. marec 2024 ob 14:21:11 CET je Frank Oltmanns napisal(a):
> The Allwinner SoC's typically have an upper and lower limit for their
> clocks' rates. Up until now, support for that has been implemented
> separately for each clock type.
> 
> Implement that functionality in the sunxi-ng's common part making use of
> the CCF rate liming capabilities, so that it is available for all clock
> types.
> 
> Suggested-by: Maxime Ripard <mripard@...nel.org>
> Signed-off-by: Frank Oltmanns <frank@...manns.dev>
> Cc: stable@...r.kernel.org

This looks pretty nice now.

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

Best regards,
Jernej

> ---
>  drivers/clk/sunxi-ng/ccu_common.c | 19 +++++++++++++++++++
>  drivers/clk/sunxi-ng/ccu_common.h |  3 +++
>  2 files changed, 22 insertions(+)
> 
> diff --git a/drivers/clk/sunxi-ng/ccu_common.c b/drivers/clk/sunxi-ng/ccu_common.c
> index 8babce55302f..ac0091b4ce24 100644
> --- a/drivers/clk/sunxi-ng/ccu_common.c
> +++ b/drivers/clk/sunxi-ng/ccu_common.c
> @@ -44,6 +44,16 @@ bool ccu_is_better_rate(struct ccu_common *common,
>  			unsigned long current_rate,
>  			unsigned long best_rate)
>  {
> +	unsigned long min_rate, max_rate;
> +
> +	clk_hw_get_rate_range(&common->hw, &min_rate, &max_rate);
> +
> +	if (current_rate > max_rate)
> +		return false;
> +
> +	if (current_rate < min_rate)
> +		return false;
> +
>  	if (common->features & CCU_FEATURE_CLOSEST_RATE)
>  		return abs(current_rate - target_rate) < abs(best_rate - target_rate);
>  
> @@ -122,6 +132,7 @@ static int sunxi_ccu_probe(struct sunxi_ccu *ccu, struct device *dev,
>  
>  	for (i = 0; i < desc->hw_clks->num ; i++) {
>  		struct clk_hw *hw = desc->hw_clks->hws[i];
> +		struct ccu_common *common = hw_to_ccu_common(hw);
>  		const char *name;
>  
>  		if (!hw)
> @@ -136,6 +147,14 @@ static int sunxi_ccu_probe(struct sunxi_ccu *ccu, struct device *dev,
>  			pr_err("Couldn't register clock %d - %s\n", i, name);
>  			goto err_clk_unreg;
>  		}
> +
> +		if (common->max_rate)
> +			clk_hw_set_rate_range(hw, common->min_rate,
> +					      common->max_rate);
> +		else
> +			WARN(common->min_rate,
> +			     "No max_rate, ignoring min_rate of clock %d - %s\n",
> +			     i, name);
>  	}
>  
>  	ret = of_clk_add_hw_provider(node, of_clk_hw_onecell_get,
> diff --git a/drivers/clk/sunxi-ng/ccu_common.h b/drivers/clk/sunxi-ng/ccu_common.h
> index 942a72c09437..329734f8cf42 100644
> --- a/drivers/clk/sunxi-ng/ccu_common.h
> +++ b/drivers/clk/sunxi-ng/ccu_common.h
> @@ -31,6 +31,9 @@ struct ccu_common {
>  	u16		lock_reg;
>  	u32		prediv;
>  
> +	unsigned long	min_rate;
> +	unsigned long	max_rate;
> +
>  	unsigned long	features;
>  	spinlock_t	*lock;
>  	struct clk_hw	hw;
> 
>