On Friday 27 April 2018 06:32 PM, Alex Elder wrote:
On 04/27/2018 07:50 AM, Arvind Yadav wrote:
On Friday 27 April 2018 05:47 PM, Alex Elder wrote:
On 04/27/2018 05:52 AM, Arvind Yadav wrote:
Replace the manual validity checks for the GPIO with the gpio_is_valid().
I haven't looked through the code paths very closely, but I think that get_named_gpio() might return -EPROBE_DEFER, which would be something we want to pass to the caller.
Yes of_get_name_gpio() can return other error value apart from -EPROBE_DEFER.
So rather than returning -ENODEV and hiding the reason the call to of_get_named_gpio() failed, you should continue returning the errno it supplies (if not a valid gpio number).
-AlexI have return -ENODEV because invalid gpio pin can be positive. static inline bool gpio_is_valid(int number) { return number >= 0 && number < ARCH_NR_GPIOS; } Here if number > ARCH_NR_GPIOS then it's invalid but return value will be positive.
Your reasoning is good. However in all three of these cases, the GPIO number you're checking is the value returned from of_get_named_gpio(). The return value is a "GPIO number to use with Linux generic GPIO API, or one of the errno value."
So unless the API of of_get_named_gpio() changes, you can be sure that if the value returned is invalid, it is a negative errno. (And if the API did change, the person making that change would be responsible for fixing all callers to ensure the change didn't break them.)
This distinction may be why the code you're changing was only testing for negative, rather than using gpio_is_valid() (you'll see it's used elsewhere in the Greybus code--even in the same source files.)
Anyway, changing the code to use gpio_is_valid() is fine. But you should avoid obscuring the reason for the error that the return value from of_get_named_gpio() provides.
-Alex
Yes, It'll be fine to return a invalid gpio as error instead of -ENODEV. I will send an updated patch.
~arvind
We can return like this " return (gpio > 0) ? -ENODEV: gpio;"
But not sure this is worth to handle this.
~arvind
Signed-off-by: Arvind Yadav arvind.yadav.cs@gmail.com
drivers/staging/greybus/arche-platform.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/staging/greybus/arche-platform.c b/drivers/staging/greybus/arche-platform.c index 83254a7..fc6bf60 100644 --- a/drivers/staging/greybus/arche-platform.c +++ b/drivers/staging/greybus/arche-platform.c @@ -448,9 +448,9 @@ static int arche_platform_probe(struct platform_device *pdev) arche_pdata->svc_reset_gpio = of_get_named_gpio(np, "svc,reset-gpio", 0);
- if (arche_pdata->svc_reset_gpio < 0) {
- if (!gpio_is_valid(arche_pdata->svc_reset_gpio)) { dev_err(dev, "failed to get reset-gpio\n");
return arche_pdata->svc_reset_gpio;
return -ENODEV; } ret = devm_gpio_request(dev, arche_pdata->svc_reset_gpio, "svc-reset"); if (ret) {@@ -468,9 +468,9 @@ static int arche_platform_probe(struct platform_device *pdev) arche_pdata->svc_sysboot_gpio = of_get_named_gpio(np, "svc,sysboot-gpio", 0);
- if (arche_pdata->svc_sysboot_gpio < 0) {
- if (!gpio_is_valid(arche_pdata->svc_sysboot_gpio)) { dev_err(dev, "failed to get sysboot gpio\n");
return arche_pdata->svc_sysboot_gpio;
return -ENODEV; } ret = devm_gpio_request(dev, arche_pdata->svc_sysboot_gpio, "sysboot0"); if (ret) {@@ -487,9 +487,9 @@ static int arche_platform_probe(struct platform_device *pdev) arche_pdata->svc_refclk_req = of_get_named_gpio(np, "svc,refclk-req-gpio", 0);
- if (arche_pdata->svc_refclk_req < 0) {
- if (!gpio_is_valid(arche_pdata->svc_refclk_req)) { dev_err(dev, "failed to get svc clock-req gpio\n");
return arche_pdata->svc_refclk_req;
return -ENODEV; } ret = devm_gpio_request(dev, arche_pdata->svc_refclk_req, "svc-clk-req");