Re: [greybus-dev] [PATCH] staging: greybus: Use gpio_is_valid()

[Arvind Yadav]

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).

                                        -Alex

I 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.

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...@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");