-----Original Message-----
From: Fabio Estevam [mailto:festevam at gmail.com]
Sent: 2015?7?29? 16:21
To: Wang Shenwei-B38339
Cc: Greg Kroah-Hartman; linux-arm-kernel at lists.infradead.org;
linux-serial at vger.kernel.org
Subject: Re: [PATCH v3 1/1] Serial: imx: add dev_pm_ops to support suspend to
ram/disk

On Wed, Jul 29, 2015 at 5:58 PM, Shenwei Wang [off-list ref]
wrote:

quoted

+static int imx_serial_port_suspend_noirq(struct device *dev) {
+       struct platform_device *pdev = to_platform_device(dev);
+       struct imx_port *sport = platform_get_drvdata(pdev);
+
+       /* Save necessary regs */
+       clk_enable(sport->clk_ipg);

clk_enable() may fail, so you should check its return value.

The check seems a little superfluous because the failure condition for clk_enable is 
(clk == NULL || IS_ERR(clk))
Once this function is called which means the initialization of the driver is successful.

quoted

+       sport->saved_reg[0] = readl(sport->port.membase + UCR1);
+       sport->saved_reg[1] = readl(sport->port.membase + UCR2);
+       sport->saved_reg[2] = readl(sport->port.membase + UCR3);
+       sport->saved_reg[3] = readl(sport->port.membase + UCR4);
+       sport->saved_reg[4] = readl(sport->port.membase + UFCR);
+       sport->saved_reg[5] = readl(sport->port.membase + UESC);
+       sport->saved_reg[6] = readl(sport->port.membase + UTIM);
+       sport->saved_reg[7] = readl(sport->port.membase + UBIR);
+       sport->saved_reg[8] = readl(sport->port.membase + UBMR);
+       sport->saved_reg[9] = readl(sport->port.membase + IMX21_UTS);
+       clk_disable(sport->clk_ipg);
+
+       dev_dbg(dev, "0x%p (%d)\r\n", sport->port.membase,
+ sport->port.line);
+
+       return 0;
+}
+
+static int imx_serial_port_resume_noirq(struct device *dev) {
+       struct platform_device *pdev = to_platform_device(dev);
+       struct imx_port *sport = platform_get_drvdata(pdev);
+
+       clk_enable(sport->clk_ipg);

Same here.

quoted

+       writel(sport->saved_reg[4], sport->port.membase + UFCR);
+       writel(sport->saved_reg[5], sport->port.membase + UESC);
+       writel(sport->saved_reg[6], sport->port.membase + UTIM);
+       writel(sport->saved_reg[7], sport->port.membase + UBIR);
+       writel(sport->saved_reg[8], sport->port.membase + UBMR);
+       writel(sport->saved_reg[9], sport->port.membase + IMX21_UTS);
+       writel(sport->saved_reg[0], sport->port.membase + UCR1);
+       writel(sport->saved_reg[1] | 0x1, sport->port.membase + UCR2);

Why this magic '| 0x1'? Can't you use a define instead?

Yes, should be a macro.

Thanks,
Shenwei