linux-kernel - Re: [PATCH v2 3/4] drm/stm: dsi: expose DSI PHY internal clock

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Date: Thu, 4 Jan 2024 14:51:08 +0100
From: Raphael Gallais-Pou <raphael.gallais-pou@...s.st.com>
To: Simon Horman <horms@...nel.org>
CC: Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski
	<krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre Torgue
	<alexandre.torgue@...s.st.com>,
        Yannick Fertre <yannick.fertre@...s.st.com>,
        Philippe Cornu <philippe.cornu@...s.st.com>,
        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>,
        Richard Cochran <richardcochran@...il.com>,
        <devicetree@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
        <dri-devel@...ts.freedesktop.org>, <netdev@...r.kernel.org>
Subject: Re: [PATCH v2 3/4] drm/stm: dsi: expose DSI PHY internal clock


On 12/8/23 17:58, Simon Horman wrote:
> On Mon, Dec 04, 2023 at 11:11:12AM +0100, Raphael Gallais-Pou wrote:
>
> ...
>
>> @@ -514,18 +675,40 @@ static int dw_mipi_dsi_stm_probe(struct platform_device *pdev)
>>  		dsi->lane_max_kbps *= 2;
>>  	}
>>  
>> -	dw_mipi_dsi_stm_plat_data.base = dsi->base;
>> -	dw_mipi_dsi_stm_plat_data.priv_data = dsi;
>> +	dsi->pdata = *pdata;
>> +	dsi->pdata.base = dsi->base;
>> +	dsi->pdata.priv_data = dsi;
>> +
>> +	dsi->pdata.max_data_lanes = 2;
>> +	dsi->pdata.phy_ops = &dw_mipi_dsi_stm_phy_ops;
>>  
>>  	platform_set_drvdata(pdev, dsi);
>>  
>> -	dsi->dsi = dw_mipi_dsi_probe(pdev, &dw_mipi_dsi_stm_plat_data);
>> +	dsi->dsi = dw_mipi_dsi_probe(pdev, &dsi->pdata);
>>  	if (IS_ERR(dsi->dsi)) {
>>  		ret = PTR_ERR(dsi->dsi);
>>  		dev_err_probe(dev, ret, "Failed to initialize mipi dsi host\n");
>>  		goto err_dsi_probe;
>>  	}
>>  
>> +	/*
>> +	 * We need to wait for the generic bridge to probe before enabling and
>> +	 * register the internal pixel clock.
>> +	 */
>> +	ret = clk_prepare_enable(dsi->pclk);
>> +	if (ret) {
>> +		DRM_ERROR("%s: Failed to enable peripheral clk\n", __func__);
>> +		goto err_dsi_probe;
>> +	}
>> +
>> +	ret = dw_mipi_dsi_clk_register(dsi, dev);
>> +	if (ret) {
>> +		DRM_ERROR("Failed to register DSI pixel clock: %d\n", ret);
> Hi Raphael,

Hi Simon,

You are right,  dsi->clk needs to be disabled in case the clock register fails
before exiting the probe.

I've sent a v3, which normally fixes it.


Regards,

Raphaël

>
> Does clk_disable_unprepare(dsi->pclk) need to be added to this unwind
> chain?
>
> Flagged by Smatch.
>
>> +		goto err_dsi_probe;
>> +	}
>> +
>> +	clk_disable_unprepare(dsi->pclk);
>> +
>>  	return 0;
>>  
>>  err_dsi_probe:
> ...