Messages in this thread Patch in this message |  | | From | Uwe Kleine-König <> | Subject | [PATCH] w1-gpio: handle of_get_gpio() returning -EPROBE_DEFER better | Date | Thu, 13 Feb 2014 23:05:28 +0100 |
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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> --- Actually I'm not completely happy with this change because IMHO if a device tree node contains:
gpios = <&gpio5 0 0 4>;
where gpio5's #gpio-cells property is <2> I'd prefer to not bind the driver with an error message instead of treating it as if
gpios = <&gpio5 0 0>;
was specified. Still this patch is a correct first step.
So something like that would be nice:
len = get_len_of_gpio_array(); if (len < 0) /* not well-formed */ return len;
if (len == 1) go on without pullup else if (len == 2) go on with pullup else scream --- drivers/w1/masters/w1-gpio.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-)
diff --git a/drivers/w1/masters/w1-gpio.c b/drivers/w1/masters/w1-gpio.c index e36b18b2817b..4b581228a4d9 100644 --- a/drivers/w1/masters/w1-gpio.c +++ b/drivers/w1/masters/w1-gpio.c @@ -68,11 +68,22 @@ 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; @@ -86,10 +97,8 @@ 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); -- 1.8.5.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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