Re: [PATCH 3/3] pch_gbe: Add MinnowBoard support

On Mon, 2013-07-15 at 11:34 +0300, Andy Shevchenko wrote:

On Fri, 2013-07-12 at 17:58 -0700, Darren Hart wrote: 

... 

quoted

+/* The AR803X PHY on the MinnowBoard requires a physical pin to be toggled to
+ * ensure it is awake for probe and init. Request the line and reset the PHY.
+ */
+static int pch_gbe_minnow_platform_init(struct pci_dev *pdev)
+{
+	int ret = 0;
+	int flags = GPIOF_DIR_OUT | GPIOF_INIT_HIGH | GPIOF_EXPORT;
+	int gpio = MINNOW_PHY_RESET_GPIO;
+
+	ret = gpio_request_one(gpio, flags, "minnow_phy_reset");
+	if (ret){
+		dev_err(&pdev->dev,
+			"ERR: Can't request PHY reset GPIO line '%d'\n", gpio);
+		return ret;
+	}
+
+	gpio_set_value(gpio, 0);
+	usleep_range(1250, 1500);
+	gpio_set_value(gpio, 1);
+	usleep_range(1250, 1500);

First of all, who is going to release gpio? Perhaps
devm_gpio_request_one?

Thanks for the pointer, this works and appears to be the best way to
handle this.

...

quoted

+ */
+int pch_gbe_phy_tx_clk_delay(struct pch_gbe_hw *hw)
+{
+	/* The RGMII interface requires a ~2ns TX clock delay. This is typically
+	 * done in layout with a longer trace or via PHY strapping, but can also
+	 * be done via PHY configuration registers.
+	 */
+	struct pch_gbe_adapter *adapter = pch_gbe_hw_to_adapter(hw);
+	u16 mii_reg;
+	int ret = 0;

No need to assign. Are you trying to shut (sparse?) warning?

On this point, I did find one instance where I initialized init only to
have my first line of executable code assign to ret, that's obviously
silly, so I fixed that one.

Here, where the first assignment is nested inside case statements or
skipped altogether with explicit returns of error codes, I prefer to
assign it explicitly. A quick survey lists 4k initialized "int ret;"
lines and 16k uninitialized.  The latter appears to be the more common,
but there is certainly precedent for the former.

-- 
Darren Hart
Intel Open Source Technology Center
Yocto Project - Technical Lead - Linux Kernel