linux-kernel - Re: [PATCH 2/2] i3c: master: Add driver for MediaTek IP

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Message-ID: <20190604095858.38ed9a28@collabora.com>
Date:   Tue, 4 Jun 2019 09:58:58 +0200
From:   Boris Brezillon <boris.brezillon@...labora.com>
To:     Qii Wang <qii.wang@...iatek.com>
Cc:     <bbrezillon@...nel.org>, devicetree@...r.kernel.org,
        srv_heupstream@...iatek.com, leilk.liu@...iatek.com,
        gregkh@...uxfoundation.org, xinping.qian@...iatek.com,
        linux-kernel@...r.kernel.org, liguo.zhang@...iatek.com,
        linux-mediatek@...ts.infradead.org, matthias.bgg@...il.com,
        linux-i3c@...ts.infradead.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 2/2] i3c: master: Add driver for MediaTek IP

On Mon, 3 Jun 2019 11:51:03 +0800
Qii Wang <qii.wang@...iatek.com> wrote:


> +static int mtk_i3c_master_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct mtk_i3c_master *master;
> +	struct resource *res;
> +	int ret, irqnr;
> +
> +	master = devm_kzalloc(dev, sizeof(*master), GFP_KERNEL);
> +	if (!master)
> +		return -ENOMEM;
> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "main");
> +	master->regs = devm_ioremap_resource(dev, res);
> +	if (IS_ERR(master->regs))
> +		return PTR_ERR(master->regs);
> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dma");
> +	master->dma_regs = devm_ioremap_resource(dev, res);
> +	if (IS_ERR(master->dma_regs))
> +		return PTR_ERR(master->dma_regs);
> +
> +	irqnr = platform_get_irq(pdev, 0);
> +	if (irqnr < 0)
> +		return irqnr;
> +
> +	ret = devm_request_irq(dev, irqnr, mtk_i3c_master_irq,
> +			       IRQF_TRIGGER_NONE, DRV_NAME, master);
> +	if (ret < 0) {
> +		dev_err(dev, "Request I3C IRQ %d fail\n", irqnr);
> +		return ret;
> +	}
> +
> +	ret = of_property_read_u32(pdev->dev.of_node, "clock-div",
> +				   &master->clk_src_div);

You say in one comment that this clock divider is fixed in HW but might
change on a per-SoC basis. If that's the case, you should get rid of
this clock-div prop and attach the divider to the compatible (using an
mtk_i3c_master_variant struct that contains a divider field).

> +	if (ret < 0)
> +		return -EINVAL;
> +
> +	spin_lock_init(&master->xferqueue.lock);
> +	INIT_LIST_HEAD(&master->xferqueue.list);
> +
> +	if (dma_set_mask(dev, DMA_BIT_MASK(33))) {
> +		dev_err(dev, "dma_set_mask return error.\n");
> +		return -EINVAL;
> +	}
> +
> +	master->clk_main = devm_clk_get(dev, "main");
> +	if (IS_ERR(master->clk_main)) {
> +		dev_err(dev, "cannot get main clock\n");
> +		return PTR_ERR(master->clk_main);
> +	}
> +	master->clk_dma = devm_clk_get(dev, "dma");
> +	if (IS_ERR(master->clk_dma)) {
> +		dev_err(dev, "cannot get dma clock\n");
> +		return PTR_ERR(master->clk_dma);
> +	}
> +
> +	master->clk_arb = devm_clk_get_optional(dev, "arb");
> +	if (IS_ERR(master->clk_arb))
> +		return PTR_ERR(master->clk_arb);
> +
> +	ret = mtk_i3c_master_clock_enable(master);
> +	if (ret) {
> +		dev_err(dev, "clock enable failed!\n");
> +		return ret;
> +	}
> +
> +	master->dev = dev;
> +	platform_set_drvdata(pdev, master);
> +
> +	ret = i3c_master_register(&master->mas_ctrler, dev,
> +				  &mtk_i3c_master_ops, false);
> +	if (ret) {
> +		dev_err(dev, "Failed to add i3c bus to i3c core\n");
> +		mtk_i3c_master_clock_disable(master);
> +		return ret;
> +	}
> +
> +	return 0;
> +}