w1-gpio: handle of_get_gpio() returning -EPROBE_DEFER better

of_get_gpio() might return -EPROBE_DEFER meaning that the driver
providing the gpio isn't ready yet. If that happens for the first gpio
the resulting kernel output without this patch is:

	w1-gpio somename: Failed to parse DT
	platform somename: Driver w1-gpio requests probe deferral

The first message is misleading and so is suppressed with this patch.

Further if determining the gpio to switch the external pullup yields
-EPROBE_DEFER this error should be passed back to the caller instead of
just continuing without pullup.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/w1/masters/w1-gpio.c b/drivers/w1/masters/w1-gpio.c
index 9709b8b484bacc8fcd9ddb4c1a88e137e2afa961..1d111e56c8c8c6c4a49badcd5f92febcf5e666d3 100644 (file)
--- a/drivers/w1/masters/w1-gpio.c
+++ b/drivers/w1/masters/w1-gpio.c
@@ -89,11 +89,22 @@ static int w1_gpio_probe_dt(struct platform_device *pdev)
                pdata->is_open_drain = 1;
 
        gpio = of_get_gpio(np, 0);
-       if (gpio < 0)
+       if (gpio < 0) {
+               if (gpio != -EPROBE_DEFER)
+                       dev_err(&pdev->dev,
+                                       "Failed to parse gpio property for data pin (%d)\n",
+                                       gpio);
+
                return gpio;
+       }
        pdata->pin = gpio;
 
-       pdata->ext_pullup_enable_pin = of_get_gpio(np, 1);
+       gpio = of_get_gpio(np, 1);
+       if (gpio == -EPROBE_DEFER)
+               return gpio;
+       /* ignore other errors as the pullup gpio is optional */
+       pdata->ext_pullup_enable_pin = gpio;
+
        pdev->dev.platform_data = pdata;
 
        return 0;
@@ -107,10 +118,8 @@ static int w1_gpio_probe(struct platform_device *pdev)
 
        if (of_have_populated_dt()) {
                err = w1_gpio_probe_dt(pdev);
-               if (err < 0) {
-                       dev_err(&pdev->dev, "Failed to parse DT\n");
+               if (err < 0)
                        return err;
-               }
        }
 
        pdata = dev_get_platdata(&pdev->dev);