Re: [PATCH 2/3] Input: rotary_encoder - fix device tree error handling
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Date: 2016-01-16 19:02:46
Hi Timo, On Fri, Jan 15, 2016 at 10:33:49PM +0200, Timo Teräs wrote:
quoted hunk ↗ jump to hunk
of_get_gpio_flags() can fail, so pass through the error code properly. Most important use case is when it returns EPROBE_DEFER so that the probe gets called again later. Signed-off-by: Timo Teräs <redacted> --- drivers/input/misc/rotary_encoder.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-)diff --git a/drivers/input/misc/rotary_encoder.c b/drivers/input/misc/rotary_encoder.c index 0f23d32..156f40f 100644 --- a/drivers/input/misc/rotary_encoder.c +++ b/drivers/input/misc/rotary_encoder.c@@ -206,7 +206,7 @@ static struct rotary_encoder_platform_data *rotary_encoder_parse_dt(struct devic struct device_node *np = dev->of_node; struct rotary_encoder_platform_data *pdata; enum of_gpio_flags flags; - int error; + int ret;
I strongly prefer variables holding error codes and not being returned to caller in success path to be called "error".
quoted hunk ↗ jump to hunk
if (!of_id || !np) return NULL;@@ -219,19 +219,25 @@ static struct rotary_encoder_platform_data *rotary_encoder_parse_dt(struct devic of_property_read_u32(np, "rotary-encoder,steps", &pdata->steps); of_property_read_u32(np, "linux,axis", &pdata->axis); - pdata->gpio_a = of_get_gpio_flags(np, 0, &flags); + ret = of_get_gpio_flags(np, 0, &flags); + if (ret < 0) + return ERR_PTR(ret); + pdata->gpio_a = ret;
Instead of doing this maybe we could switch to gpiod interface that handles polarity internally and does not depend on OF? The only issue is that we have a few board files in tree that use raw gpio numbers so we'll need to convert them... Thanks.
pdata->inverted_a = flags & OF_GPIO_ACTIVE_LOW;
- pdata->gpio_b = of_get_gpio_flags(np, 1, &flags);
+ ret = of_get_gpio_flags(np, 1, &flags);
+ if (ret < 0)
+ return ERR_PTR(ret);
+ pdata->gpio_b = ret;
pdata->inverted_b = flags & OF_GPIO_ACTIVE_LOW;
pdata->relative_axis =
of_property_read_bool(np, "rotary-encoder,relative-axis");
pdata->rollover = of_property_read_bool(np, "rotary-encoder,rollover");
- error = of_property_read_u32(np, "rotary-encoder,steps-per-period",
- &pdata->steps_per_period);
- if (error) {
+ ret = of_property_read_u32(np, "rotary-encoder,steps-per-period",
+ &pdata->steps_per_period);
+ if (ret) {
/*
* The 'half-period' property has been deprecated, you must use
* 'steps-per-period' and set an appropriate value, but we still
--
2.7.0
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