[PATCH v1] regulator: gpio: check return value of of_get_named_gpio

[PATCH v1] regulator: gpio: check return value of of_get_named_gpio

[Mihai Mihalache]

At boot time the regulator driver can be initialized before the
gpio, in which case the call to of_get_named_gpio will return
EPROBE_DEFER. This value is silently passed to regulator_register
which will return success, although the gpio is not registered
(regulator_ena_gpio_request not called) as the value passed is
detected as invalid. The gpio_regulator_probe will therefore
succeed win no gpio requested.

Signed-off-by: Mihai Mihalache <mihai.d.mihalache@intel.com>
---

History:
	V1:
	- Fix comment from Mark Brown

 drivers/regulator/gpio-regulator.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/regulator/gpio-regulator.c b/drivers/regulator/gpio-regulator.c
index 464018d..9108c57 100644
--- a/drivers/regulator/gpio-regulator.c
+++ b/drivers/regulator/gpio-regulator.c
@@ -162,6 +162,8 @@ of_get_gpio_regulator_config(struct device *dev, struct device_node *np,
 	of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
 
 	config->enable_gpio = of_get_named_gpio(np, "enable-gpio", 0);
+	if (IS_ERR_VALUE(config->enable_gpio))
+		return ERR_PTR(config->enable_gpio);
 
 	/* Fetch GPIOs. - optional property*/
 	ret = of_gpio_count(np);
-- 
2.1.4

Re: [PATCH v1] regulator: gpio: check return value of of_get_named_gpio

[Mark Brown]

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On Thu, Mar 10, 2016 at 02:04:59AM -0800, Mihai Mihalache wrote:

>  	config->enable_gpio = of_get_named_gpio(np, "enable-gpio", 0);
> +	if (IS_ERR_VALUE(config->enable_gpio))
> +		return ERR_PTR(config->enable_gpio);

This is an incompatible behaviour change.  enable-gpio is an optional
property, we check later if we got a valid GPIO and happily continue if
we didn't.  The driver should instead explicitly check for -EPROBE_DEFER
and handle that case separately, allowing the device to probe in cases
where the GPIO is just not provided.

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