linux-kernel - Re: [PATCH v3 2/2] ASoC: fsl_aud2htx: Add aud2htx module driver

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Message-ID: <20201105013539.GA16459@Asurada-Nvidia>
Date:   Wed, 4 Nov 2020 17:35:40 -0800
From:   Nicolin Chen <nicoleotsuka@...il.com>
To:     Shengjiu Wang <shengjiu.wang@....com>
Cc:     timur@...nel.org, Xiubo.Lee@...il.com, festevam@...il.com,
        broonie@...nel.org, perex@...ex.cz, tiwai@...e.com,
        alsa-devel@...a-project.org, lgirdwood@...il.com,
        robh+dt@...nel.org, devicetree@...r.kernel.org,
        linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 2/2] ASoC: fsl_aud2htx: Add aud2htx module driver

On Mon, Nov 02, 2020 at 09:52:27AM +0800, Shengjiu Wang wrote:
> The AUD2HTX is a digital module that provides a bridge between
> the Audio Subsystem and the HDMI RTX Subsystem. This module
> includes intermediate storage to queue SDMA transactions prior
> to being synchronized and passed to the HDMI RTX Subsystem over
> the Audio Link.
> 
> The AUD2HTX contains a DMA request routed to the SDMA module.
> This DMA request is controlled based on the watermark level in
> the 32-entry sample buffer.
> 
> Signed-off-by: Shengjiu Wang <shengjiu.wang@....com>

Acked-by: Nicolin Chen <nicoleotsuka@...il.com>

Despite some small comments inline.

> +static int fsl_aud2htx_dai_probe(struct snd_soc_dai *cpu_dai)
> +{
> +	struct fsl_aud2htx *aud2htx = dev_get_drvdata(cpu_dai->dev);
> +
> +	/* DMA request when number of entries < WTMK_LOW */
> +	regmap_update_bits(aud2htx->regmap, AUD2HTX_CTRL_EXT,
> +			   AUD2HTX_CTRE_DT_MASK, 0);
> +
> +	/* Disable interrupts*/
> +	regmap_update_bits(aud2htx->regmap, AUD2HTX_IRQ_MASK,
> +			   AUD2HTX_WM_HIGH_IRQ_MASK |
> +			   AUD2HTX_WM_LOW_IRQ_MASK |
> +			   AUD2HTX_OVF_MASK,
> +			   AUD2HTX_WM_HIGH_IRQ_MASK |
> +			   AUD2HTX_WM_LOW_IRQ_MASK |
> +			   AUD2HTX_OVF_MASK);
> +
> +	/* Configure watermark */
> +	regmap_update_bits(aud2htx->regmap, AUD2HTX_CTRL_EXT,
> +			   AUD2HTX_CTRE_WL_MASK,
> +			   AUD2HTX_WTMK_LOW << AUD2HTX_CTRE_WL_SHIFT);
> +	regmap_update_bits(aud2htx->regmap, AUD2HTX_CTRL_EXT,
> +			   AUD2HTX_CTRE_WH_MASK,
> +			   AUD2HTX_WTMK_HIGH << AUD2HTX_CTRE_WH_SHIFT);

If there isn't a hard requirement from hardware, feels better to
combine all the writes to AUD2HTX_CTRL_EXT into one single MMIO.

> +static irqreturn_t fsl_aud2htx_isr(int irq, void *dev_id)
> +{
> +	return IRQ_HANDLED;

Empty isr? Perhaps can drop the request_irq() at all?

> +static int fsl_aud2htx_probe(struct platform_device *pdev)
> +{
> +	struct fsl_aud2htx *aud2htx;
> +	struct resource *res;
> +	void __iomem *regs;
> +	int ret, irq;
> +
> +	aud2htx = devm_kzalloc(&pdev->dev, sizeof(*aud2htx), GFP_KERNEL);
> +	if (!aud2htx)
> +		return -ENOMEM;
> +
> +	aud2htx->pdev = pdev;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	regs = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(regs)) {
> +		dev_err(&pdev->dev, "failed ioremap\n");
> +		return PTR_ERR(regs);
> +	}
> +
> +	aud2htx->regmap = devm_regmap_init_mmio(&pdev->dev, regs,
> +						&fsl_aud2htx_regmap_config);
> +	if (IS_ERR(aud2htx->regmap)) {
> +		dev_err(&pdev->dev, "failed to init regmap");
> +		return PTR_ERR(aud2htx->regmap);
> +	}
> +
> +	irq = platform_get_irq(pdev, 0);
> +	if (irq < 0) {
> +		dev_err(&pdev->dev, "no irq for node %s\n",
> +			dev_name(&pdev->dev));

dev_err() already prints dev_name, so not necessary to print again.