On Saturday, 21 July 2018 15:03:57 MSK Dmitry Osipenko wrote: > On Saturday, 21 July 2018 14:55:21 MSK Marcel Ziswiler wrote: > > On Sat, 2018-07-21 at 14:17 +0300, Dmitry Osipenko wrote: > > > On Saturday, 21 July 2018 12:56:15 MSK Mark Brown wrote: > > > > On Fri, Jul 20, 2018 at 12:31:07PM +0000, Marcel Ziswiler wrote: > > > > > On Fri, 2018-07-20 at 13:16 +0100, Mark Brown wrote: > > > > > > > ac97->sync_gpio = of_get_named_gpio(pdev- > > > > > > > > > > > > > > > >dev.of_node, > > > > > > > > > > > > > > > "nvidia,codec- > > > > > > > > > > > > > > sync- > > > > > > > > > > > > > > gpio", 0); > > > > > > > > > > > > > > if (!gpio_is_valid(ac97->sync_gpio)) { > > > > > > > > > > > > > > - dev_err(&pdev->dev, "no codec-sync GPIO > > > > > > > supplied\n"); > > > > > > > + ret = ac97->sync_gpio; > > > > > > > + dev_err(&pdev->dev, "no codec-sync GPIO > > > > > > > supplied: > > > > > > > %d\n", ret); > > > > > > > > > > > > > > goto err_clk_put; > > > > > > > > > > > > > > } > > > > > > > > > > > > This isn't reporting an error code associated with the attempt > > > > > > to > > > > > > find a > > > > > > codec-sync GPIO, it's the result of some other operation. > > > > > > > > > > What exactly is then the of_get_named_gpio() above please doing > > > > > if > > > > > not getting the codec sync GPIO? I am not following you, sorry. > > > > > > > > It's not in any way involved in setting the value of ret, whatever > > > > value > > > > that has it's nothing to do with that operation. > > > > > > The comment to gpio_is_valid() says that it "Returns GPIO number to > > > use with > > > Linux generic GPIO API, or one of the errno value on the error > > > condition". > > > Comment doesn't explicitly states that the returned GPIO number is > > > always > > > valid, but it is kinda implied. > > > > Do you mean I should be assigning the return value of gpio_is_valid() > > to ret and use that instead? > > No, gpio_is_valid() returns a boolean. I think your patch is fine as it is > is. > > Probably Mark meant something like this: > > ac97->sync_gpio = of_get_named_gpio(pdev->dev.of_node, > "nvidia,codec-sync-gpio", 0); > if (ac97->sync_gpio < 0) { > ret = ac97->sync_gpio; > dev_err(&pdev->dev, "no codec-sync GPIO supplied: %d\n", > ret); goto err_clk_put; > } > > if (!gpio_is_valid(ac97->sync_gpio)) { > ret = -EINVAL; > goto err_clk_put; > } > > But that is not needed because of_get_named_gpio() returns either a valid > GPIO number or a error code.
Also note that tegra20_ac97 code doesn't check the returned value of: gpio_request(workdata->sync_gpio, "codec-sync"); That is a bit fragile. Probably would be better to move the GPIO requesting to the drivers probe function using the devm_gpio_request_one() and fail the driver probing if requesting fails. That should be a distinct patch if you'll want to implement that.