On 2014-08-08 at 13:32:03 +0200, Matthias Brugger [off-list ref] wrote:

[...]

+static int mtk8250_probe(struct platform_device *pdev)
+{
+	struct uart_8250_port uart = {};
+	struct resource *regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	struct resource *irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	struct mtk8250_data *data;
+	int err;
+
+	if (!regs || !irq) {
+		dev_err(&pdev->dev, "no registers/irq defined\n");
+		return -EINVAL;
+	}
+
+	spin_lock_init(&uart.port.lock);
+	uart.port.mapbase = regs->start;
+	uart.port.irq = irq->start;
+	uart.port.pm = mtk8250_do_pm;
+	uart.port.type = PORT_16550;
+	uart.port.flags = UPF_BOOT_AUTOCONF | UPF_FIXED_PORT;
+	uart.port.dev = &pdev->dev;
+
+	uart.port.membase = devm_ioremap(&pdev->dev, regs->start,
+					 resource_size(regs));
+	if (!uart.port.membase)
+		return -ENOMEM;

You can use devm_ioremap_resource here and get rid of the check for
!regs above, since devm_ioremap_resource already does that.

	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	...

	uart.port.membase = devm_ioremap_resource(&pdev->dev, regs);
	if (IS_ERR(uart.port.membase))
		return PTR_ERR(uart.port.membase);

+
+	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;

I'd suggest to move this kzalloc and the ioremap before the uart.port
initialization part above, so you can error out early in case of any
failure.

+
+	uart.port.iotype = UPIO_MEM32;
+	uart.port.regshift = 2;
+	uart.port.private_data = data;
+	uart.port.set_termios = mtk8250_set_termios;
+
+	if (pdev->dev.of_node) {
+		err = mtk8250_probe_of(&uart.port, data);
+		if (err)
+			return err;
+	} else
+		return -ENODEV;

This could also be moved up, directly below devm_kzalloc.

+
+	/* Disable Rate Fix function */
+	writel(0x0, uart.port.membase +
+			(MTK_UART_RATE_FIX << uart.port.regshift));
+
+	data->line = serial8250_register_8250_port(&uart);
+	if (data->line < 0)
+		return data->line;
+
+	platform_set_drvdata(pdev, data);
+
+	pm_runtime_set_active(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
+
+	return 0;
+}
+
+static int mtk8250_remove(struct platform_device *pdev)
+{
+	struct mtk8250_data *data = platform_get_drvdata(pdev);
+
+	pm_runtime_get_sync(&pdev->dev);
+
+	serial8250_unregister_port(data->line);
+	if (!IS_ERR(data->clk)) {
+		clk_disable_unprepare(data->clk);
+		clk_put(data->clk);
+	}
+
+	pm_runtime_disable(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int mtk8250_suspend(struct device *dev)
+{
+	struct mtk8250_data *data = dev_get_drvdata(dev);
+
+	serial8250_suspend_port(data->line);
+
+	return 0;
+}
+
+static int mtk8250_resume(struct device *dev)
+{
+	struct mtk8250_data *data = dev_get_drvdata(dev);
+
+	serial8250_resume_port(data->line);
+
+	return 0;
+}
+#endif /* CONFIG_PM_SLEEP */
+
+#ifdef CONFIG_PM_RUNTIME
+static int mtk8250_runtime_suspend(struct device *dev)
+{
+	struct mtk8250_data *data = dev_get_drvdata(dev);
+
+	if (!IS_ERR(data->clk))
+		clk_disable_unprepare(data->clk);
+
+	return 0;
+}
+
+static int mtk8250_runtime_resume(struct device *dev)
+{
+	struct mtk8250_data *data = dev_get_drvdata(dev);
+
+	if (!IS_ERR(data->clk))
+		clk_prepare_enable(data->clk);
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops mtk8250_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(mtk8250_suspend, mtk8250_resume)
+	SET_RUNTIME_PM_OPS(mtk8250_runtime_suspend, mtk8250_runtime_resume,
+				NULL)
+};
+
+static const struct of_device_id mtk8250_of_match[] = {
+	{ .compatible = "mediatek,mt6577-uart" },
+	{ /* Sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, mtk8250_of_match);
+
+static struct platform_driver mtk8250_platform_driver = {
+	.driver = {
+		.name		= "mt6577-uart",
+		.owner		= THIS_MODULE,

This doesn't need to be set here,
module_platform_driver/platform_driver_register take care of setting it.

+		.pm		= &mtk8250_pm_ops,
+		.of_match_table	= mtk8250_of_match,
+	},
+	.probe			= mtk8250_probe,
+	.remove			= mtk8250_remove,
+};
+module_platform_driver(mtk8250_platform_driver);
+
+MODULE_AUTHOR("Matthias Brugger");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Mediatek 8250 serial port driver");