linux-kernel - Re: [PATCH v7 6/9] drm/mediatek: add dsi interrupt control

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Date:   Wed, 7 Sep 2016 09:39:08 +0800
From:   CK Hu <ck.hu@...iatek.com>
To:     YT Shen <yt.shen@...iatek.com>
CC:     <dri-devel@...ts.freedesktop.org>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        David Airlie <airlied@...ux.ie>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Daniel Kurtz <djkurtz@...omium.org>,
        Mao Huang <littlecvr@...omium.org>,
        Bibby Hsieh <bibby.hsieh@...iatek.com>,
        "Daniel Vetter" <daniel.vetter@...ll.ch>,
        Thierry Reding <thierry.reding@...il.com>,
        Jie Qiu <jie.qiu@...iatek.com>,
        Maxime Ripard <maxime.ripard@...e-electrons.com>,
        Chris Wilson <chris@...is-wilson.co.uk>,
        shaoming chen <shaoming.chen@...iatek.com>,
        Jitao Shi <jitao.shi@...iatek.com>,
        Boris Brezillon <boris.brezillon@...e-electrons.com>,
        Dan Carpenter <dan.carpenter@...cle.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-mediatek@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <srv_heupstream@...iatek.com>,
        Sascha Hauer <kernel@...gutronix.de>,
        <yingjoe.chen@...iatek.com>, <emil.l.velikov@...il.com>
Subject: Re: [PATCH v7 6/9] drm/mediatek: add dsi interrupt control

Hi, YT:

On Fri, 2016-09-02 at 19:24 +0800, YT Shen wrote:
> From: shaoming chen <shaoming.chen@...iatek.com>
> 
> add dsi interrupt control
> 
> Signed-off-by: shaoming chen <shaoming.chen@...iatek.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_dsi.c | 76 ++++++++++++++++++++++++++++++++++++++
>  1 file changed, 76 insertions(+)
> 

[snip...]

>  
> +static wait_queue_head_t _dsi_irq_wait_queue;

I think it's better to move this global variable into platform driver
data. Maybe one day you have two dsi device and one global variable is
not enough.

> +

[snip...]

> +
> +static irqreturn_t mtk_dsi_irq(int irq, void *dev_id)
> +{
> +	struct mtk_dsi *dsi = dev_id;
> +	u32 status, tmp;
> +	u32 flag = LPRX_RD_RDY_INT_FLAG | CMD_DONE_INT_FLAG | VM_DONE_INT_FLAG;
> +
> +	status = readl(dsi->regs + DSI_INTSTA);

If you define as

status = readl(dsi->regs + DSI_INTSTA) & flag;

You can remove 'flag' in below statements and reduce code size.

> +
> +	if (status & flag) {
> +		do {
> +			mtk_dsi_mask(dsi, DSI_RACK, RACK, RACK);
> +			tmp = readl(dsi->regs + DSI_INTSTA);
> +		} while (tmp & DSI_BUSY);
> +
> +		mtk_dsi_mask(dsi, DSI_INTSTA, status & flag, 0);
> +		mtk_dsi_irq_data_set(dsi, status & flag);
> +		wake_up_interruptible(&_dsi_irq_wait_queue);
> +	}
> +
> +	return IRQ_HANDLED;
> +}
> +

[snip...]

>  
> @@ -869,8 +926,27 @@ static int mtk_dsi_probe(struct platform_device *pdev)
>  		return ret;
>  	}
>  
> +	irq_num = platform_get_irq(pdev, 0);
> +	if (irq_num < 0) {
> +		dev_err(&pdev->dev, "failed to request dsi irq resource\n");
> +		return -EPROBE_DEFER;
> +	}
> +
> +	irq_set_status_flags(irq_num, IRQ_TYPE_LEVEL_LOW);
> +	ret = devm_request_irq(&pdev->dev, irq_num, mtk_dsi_irq,
> +			       IRQF_TRIGGER_LOW, dev_name(&pdev->dev), dsi);
> +	if (ret) {
> +		dev_err(&pdev->dev, "failed to request mediatek dsi irq\n");
> +		return -EPROBE_DEFER;
> +	}
> +
> +	dsi->irq_data = 0;

You use devm_kzalloc() to allocate 'dsi', so this statement is
redundant.

> +	dev_info(dev, "dsi irq num is 0x%x\n", irq_num);
> +
>  	platform_set_drvdata(pdev, dsi);
>  
> +	init_waitqueue_head(&_dsi_irq_wait_queue);
> +
>  	return component_add(&pdev->dev, &mtk_dsi_component_ops);
>  }


Regards,
CK