On Mon, 3 Jun 2019 11:51:03 +0800
Qii Wang [off-list ref] 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;
+}

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