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From: Jernej =?utf-8?B?xaBrcmFiZWM=?= <jernej.skrabec@gmail.com>
To: Michael Turquette <mturquette@baylibre.com>,
 Stephen Boyd <sboyd@kernel.org>, Chen-Yu Tsai <wens@csie.org>,
 Samuel Holland <samuel@sholland.org>,
 Guido =?ISO-8859-1?Q?G=FCnther?= <agx@sigxcpu.org>,
 Purism Kernel Team <kernel@puri.sm>, Ondrej Jirman <megi@xff.cz>,
 Neil Armstrong <neil.armstrong@linaro.org>,
 Jessica Zhang <quic_jesszhan@quicinc.com>, Sam Ravnborg <sam@ravnborg.org>,
 Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
 Maxime Ripard <mripard@kernel.org>, Thomas Zimmermann <tzimmermann@suse.de>,
 David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>,
 Rob Herring <robh+dt@kernel.org>,
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
 Conor Dooley <conor+dt@kernel.org>, 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,
 dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org,
 Frank Oltmanns <frank@oltmanns.dev>
Subject:
 Re: [PATCH v2 3/6] clk: sunxi-ng: nkm: Support minimum and maximum rate
Date: Mon, 05 Feb 2024 18:56:09 +0100
Message-ID: <4543794.LvFx2qVVIh@jernej-laptop>
In-Reply-To: <20240205-pinephone-pll-fixes-v2-3-96a46a2d8c9b@oltmanns.dev>
References:
 <20240205-pinephone-pll-fixes-v2-0-96a46a2d8c9b@oltmanns.dev>
 <20240205-pinephone-pll-fixes-v2-3-96a46a2d8c9b@oltmanns.dev>
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Dne ponedeljek, 05. februar 2024 ob 16:22:26 CET je Frank Oltmanns napisal(a):
> According to the Allwinner User Manual, the Allwinner A64 requires
> PLL-MIPI to run at 500MHz-1.4GHz. Add support for that to ccu_nkm.
> 
> Signed-off-by: Frank Oltmanns <frank@oltmanns.dev>
> ---
>  drivers/clk/sunxi-ng/ccu_nkm.c | 13 +++++++++++++
>  drivers/clk/sunxi-ng/ccu_nkm.h |  2 ++
>  2 files changed, 15 insertions(+)
> 
> diff --git a/drivers/clk/sunxi-ng/ccu_nkm.c b/drivers/clk/sunxi-ng/ccu_nkm.c
> index 1168d894d636..7d135908d6e0 100644
> --- a/drivers/clk/sunxi-ng/ccu_nkm.c
> +++ b/drivers/clk/sunxi-ng/ccu_nkm.c
> @@ -181,6 +181,12 @@ static unsigned long ccu_nkm_round_rate(struct ccu_mux_internal *mux,
>  	if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
>  		rate *= nkm->fixed_post_div;
>  
> +	if (nkm->min_rate && rate < nkm->min_rate)
> +		rate = nkm->min_rate;
> +
> +	if (nkm->max_rate && rate > nkm->max_rate)
> +		rate = nkm->max_rate;

Please take a look at ccu_nm_round_rate() code. You need to consider postdiv
and you can return immediately.

> +
>  	if (!clk_hw_can_set_rate_parent(&nkm->common.hw))
>  		rate = ccu_nkm_find_best(*parent_rate, rate, &_nkm, &nkm->common);
>  	else
> @@ -220,6 +226,13 @@ 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;
>  
> +
> +	if (nkm->min_rate && rate < nkm->min_rate)
> +		rate = nkm->min_rate;
> +
> +	if (nkm->max_rate && rate > nkm->max_rate)
> +		rate = nkm->max_rate;
> +

No need for this, clk subsystem calls round rate before setting actual clock
rate.

Best regards,
Jernej

>  	ccu_nkm_find_best(parent_rate, rate, &_nkm, &nkm->common);
>  
>  	spin_lock_irqsave(nkm->common.lock, flags);
> diff --git a/drivers/clk/sunxi-ng/ccu_nkm.h b/drivers/clk/sunxi-ng/ccu_nkm.h
> index c409212ee40e..358a9df6b6a0 100644
> --- a/drivers/clk/sunxi-ng/ccu_nkm.h
> +++ b/drivers/clk/sunxi-ng/ccu_nkm.h
> @@ -27,6 +27,8 @@ struct ccu_nkm {
>  	struct ccu_mux_internal	mux;
>  
>  	unsigned int		fixed_post_div;
> +	unsigned long		min_rate;
> +	unsigned long		max_rate;
>  	unsigned long		max_m_n_ratio;
>  	unsigned long		min_parent_m_ratio;
>  
> 
>