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Date: Fri, 17 Oct 2025 17:20:18 +0200
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Subject: Re: [PATCH 20/39] drm/imx: dc: Configure display CSR clock feed
 select
To: Frank Li <Frank.li@nxp.com>
Cc: dri-devel@lists.freedesktop.org, Abel Vesa <abelvesa@kernel.org>,
 Conor Dooley <conor+dt@kernel.org>, Fabio Estevam <festevam@gmail.com>,
 Krzysztof Kozlowski <krzk+dt@kernel.org>,
 Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
 Liu Ying <victor.liu@nxp.com>, Lucas Stach <l.stach@pengutronix.de>,
 Peng Fan <peng.fan@nxp.com>, Pengutronix Kernel Team
 <kernel@pengutronix.de>, Rob Herring <robh@kernel.org>,
 Shawn Guo <shawnguo@kernel.org>, Thomas Zimmermann <tzimmermann@suse.de>,
 devicetree@vger.kernel.org, imx@lists.linux.dev,
 linux-arm-kernel@lists.infradead.org, linux-clk@vger.kernel.org
References: <20251011170213.128907-1-marek.vasut@mailbox.org>
 <20251011170213.128907-21-marek.vasut@mailbox.org>
 <aO1JmAuSWn6BN6hs@lizhi-Precision-Tower-5810>
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From: Marek Vasut <marek.vasut@mailbox.org>
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On 10/13/25 8:48 PM, Frank Li wrote:

Hello Frank,

>> @@ -119,6 +127,17 @@ static int dc_drm_bind(struct device *dev)
>>   	if (ret)
>>   		return ret;
>>
>> +	if (priv->regmap) {
>> +		regmap_write_bits(priv->regmap, DISPLAY_ENGINES_CLOCK_CONTROL,
>> +				  DISP_CLK0_SEL | DISP_CLK1_SEL,
>> +				  FIELD_PREP(DISP_CLK0_SEL,
>> +				             ((dc_drm->encoder[0].encoder_type == DRM_MODE_ENCODER_DSI) ?
>> +					     DISP_CLK_SEL_CCM : DISP_CLK_SEL_LVDS)) |
>> +				  FIELD_PREP(DISP_CLK1_SEL,
>> +				             ((dc_drm->encoder[1].encoder_type == DRM_MODE_ENCODER_DSI) ?
>> +					     DISP_CLK_SEL_CCM : DISP_CLK_SEL_LVDS)));
>> +	}
>> +
> 
> why not export as clock providor and use clk API to do that?
I don't think there are any clock operations 
(enable/disable/set_rate/...) besides controlling this selector/mux 
(set_parent), so using the clock API would have massive overhead for 
little gain.