linux-kernel - Re: [PATCH 5/5] soundwire: qcom: add sdw_master

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Message-ID: <81e2101e-d7ce-d023-5c35-ac6b55ea7166@linaro.org>
Date:   Fri, 20 Mar 2020 17:01:21 +0000
From:   Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
To:     Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>,
        alsa-devel@...a-project.org
Cc:     linux-kernel@...r.kernel.org, tiwai@...e.de, broonie@...nel.org,
        vkoul@...nel.org, gregkh@...uxfoundation.org, jank@...ence.com,
        slawomir.blauciak@...el.com,
        Bard liao <yung-chuan.liao@...ux.intel.com>,
        Rander Wang <rander.wang@...ux.intel.com>,
        Ranjani Sridharan <ranjani.sridharan@...ux.intel.com>,
        Hui Wang <hui.wang@...onical.com>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Sanyog Kale <sanyog.r.kale@...el.com>,
        "open list:ARM/QUALCOMM SUPPORT" <linux-arm-msm@...r.kernel.org>
Subject: Re: [PATCH 5/5] soundwire: qcom: add sdw_master_device support



On 20/03/2020 16:29, Pierre-Louis Bossart wrote:
> Add new device as a child of the platform device, following the
> following hierarchy:
> 
> platform_device
>      sdw_master_device
>          sdw_slave0

Why can't we just remove the platform device layer here and add 
sdw_master_device directly?

What is it stopping doing that?

--srini


> 	...
> 	sdw_slaveN
> 
> For the Qualcomm implementation no sdw_master_driver is registered so
> the dais have to be registered using the platform_device and likely
> all power management is handled at the platform device level.
> 
> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
> ---
>   drivers/soundwire/qcom.c | 29 +++++++++++++++++++++++++----
>   1 file changed, 25 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/soundwire/qcom.c b/drivers/soundwire/qcom.c
> index 77783ae4b71d..86b46415e50b 100644
> --- a/drivers/soundwire/qcom.c
> +++ b/drivers/soundwire/qcom.c
> @@ -89,6 +89,7 @@ struct qcom_swrm_port_config {
>   struct qcom_swrm_ctrl {
>   	struct sdw_bus bus;
>   	struct device *dev;
> +	struct sdw_master_device *md;
>   	struct regmap *regmap;
>   	struct completion *comp;
>   	struct work_struct slave_work;
> @@ -775,14 +776,31 @@ static int qcom_swrm_probe(struct platform_device *pdev)
>   	mutex_init(&ctrl->port_lock);
>   	INIT_WORK(&ctrl->slave_work, qcom_swrm_slave_wq);
>   
> -	ctrl->bus.dev = dev;
> +	/*
> +	 * add sdw_master_device.
> +	 * For the Qualcomm implementation there is no driver.
> +	 */
> +	ctrl->md = sdw_master_device_add(NULL,	/* no driver name */
> +					 dev,	/* platform device is parent */
> +					 dev->fwnode,
> +					 0,	/* only one link supported */
> +					 NULL);	/* no context */
> +	if (IS_ERR(ctrl->md)) {
> +		dev_err(dev, "Could not create sdw_master_device\n");
> +		ret = PTR_ERR(ctrl->md);
> +		goto err_clk;
> +	}
> +
> +	/* the bus uses the sdw_master_device, not the platform device */
> +	ctrl->bus.dev = &ctrl->md->dev;
> +
>   	ctrl->bus.ops = &qcom_swrm_ops;
>   	ctrl->bus.port_ops = &qcom_swrm_port_ops;
>   	ctrl->bus.compute_params = &qcom_swrm_compute_params;
>   
>   	ret = qcom_swrm_get_port_config(ctrl);
>   	if (ret)
> -		goto err_clk;
> +		goto err_md;
>   
>   	params = &ctrl->bus.params;
>   	params->max_dr_freq = DEFAULT_CLK_FREQ;
> @@ -809,14 +827,14 @@ static int qcom_swrm_probe(struct platform_device *pdev)
>   					"soundwire", ctrl);
>   	if (ret) {
>   		dev_err(dev, "Failed to request soundwire irq\n");
> -		goto err_clk;
> +		goto err_md;
>   	}
>   
>   	ret = sdw_add_bus_master(&ctrl->bus);
>   	if (ret) {
>   		dev_err(dev, "Failed to register Soundwire controller (%d)\n",
>   			ret);
> -		goto err_clk;
> +		goto err_md;
>   	}
>   
>   	qcom_swrm_init(ctrl);
> @@ -832,6 +850,8 @@ static int qcom_swrm_probe(struct platform_device *pdev)
>   
>   err_master_add:
>   	sdw_delete_bus_master(&ctrl->bus);
> +err_md:
> +	device_unregister(&ctrl->md->dev);
>   err_clk:
>   	clk_disable_unprepare(ctrl->hclk);
>   err_init:
> @@ -843,6 +863,7 @@ static int qcom_swrm_remove(struct platform_device *pdev)
>   	struct qcom_swrm_ctrl *ctrl = dev_get_drvdata(&pdev->dev);
>   
>   	sdw_delete_bus_master(&ctrl->bus);
> +	device_unregister(&ctrl->md->dev);
>   	clk_disable_unprepare(ctrl->hclk);
>   
>   	return 0;
>