| Message ID | 1457438528-29054-4-git-send-email-ldewangan@nvidia.com |
|---|---|
| State | New |
| Headers | show |
On Tue, Mar 08, 2016 at 05:32:06PM +0530, Laxman Dewangan wrote: > If GPIO hog configuration failed while adding OF based > gpiochip() then return the error instead of ignoring it. > > This helps of properly handling the gpio driver dependency. > > When adding the gpio hog nodes for NVIDIA's Tegra210 platforms, > the gpio_hogd() fails with EPROBE_DEFER because pinctrl is not > ready at this time and gpio_request() for Tegra GPIO driver > returns error. The error was not causing the Tegra GPIO driver > to fail as the error was getting ignored. > > Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com> > Cc: Benoit Parrot <bparrot@ti.com> > Cc: Alexandre Courbot <acourbot@nvidia.com> > --- > drivers/gpio/gpiolib-of.c | 15 +++++++++------ > 1 file changed, 9 insertions(+), 6 deletions(-) Reviewed-by: Thierry Reding <treding@nvidia.com>
On 03/08/2016 05:02 AM, Laxman Dewangan wrote: > If GPIO hog configuration failed while adding OF based > gpiochip() then return the error instead of ignoring it. > > This helps of properly handling the gpio driver dependency. > > When adding the gpio hog nodes for NVIDIA's Tegra210 platforms, > the gpio_hogd() fails with EPROBE_DEFER because pinctrl is not > ready at this time and gpio_request() for Tegra GPIO driver > returns error. The error was not causing the Tegra GPIO driver > to fail as the error was getting ignored. > diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c > @@ -218,9 +220,12 @@ static void of_gpiochip_scan_gpios(struct gpio_chip *chip) > if (IS_ERR(desc)) > continue; > > - if (gpiod_hog(desc, name, lflags, dflags)) > - continue; > + ret = gpiod_hog(desc, name, lflags, dflags); > + if (ret < 0) > + return ret; > } > + > + return 0; > } If there are multiple child nodes (which the code above is looping over), and the hog for entries 0, 1, 2 succeed and the hog for entry 3 fails, don't you need to go back and unhog for nodes 0..2 so that the next time this function is called, those hogs won't already be in place thus preventing them from being hogged the second time around? Or does hogging not take ownership of the resource and thus prevent it from being acquired again? -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wednesday 09 March 2016 10:41 PM, Stephen Warren wrote: > On 03/08/2016 05:02 AM, Laxman Dewangan wrote: >> If GPIO hog configuration failed while adding OF based >> gpiochip() then return the error instead of ignoring it. >> >> This helps of properly handling the gpio driver dependency. >> >> When adding the gpio hog nodes for NVIDIA's Tegra210 platforms, >> the gpio_hogd() fails with EPROBE_DEFER because pinctrl is not >> ready at this time and gpio_request() for Tegra GPIO driver >> returns error. The error was not causing the Tegra GPIO driver >> to fail as the error was getting ignored. > >> diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c > >> @@ -218,9 +220,12 @@ static void of_gpiochip_scan_gpios(struct >> gpio_chip *chip) >> if (IS_ERR(desc)) >> continue; >> >> - if (gpiod_hog(desc, name, lflags, dflags)) >> - continue; >> + ret = gpiod_hog(desc, name, lflags, dflags); >> + if (ret < 0) >> + return ret; >> } >> + >> + return 0; >> } > > If there are multiple child nodes (which the code above is looping > over), and the hog for entries 0, 1, 2 succeed and the hog for entry 3 > fails, don't you need to go back and unhog for nodes 0..2 so that the > next time this function is called, those hogs won't already be in > place thus preventing them from being hogged the second time around? > Or does hogging not take ownership of the resource and thus prevent it > from being acquired again? The gpiolib take care per the error handling: status = of_gpiochip_add(chip); if (status) goto err_remove_chip; ::: err_remove_chip: acpi_gpiochip_remove(chip); gpiochip_free_hogs(chip); of_gpiochip_remove(chip); -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c index f2ba1a4..d81dbd8 100644 --- a/drivers/gpio/gpiolib-of.c +++ b/drivers/gpio/gpiolib-of.c @@ -201,14 +201,16 @@ static struct gpio_desc *of_parse_own_gpio(struct device_node *np, * * This is only used by of_gpiochip_add to request/set GPIO initial * configuration. + * It retures error if it fails otherwise 0 on success. */ -static void of_gpiochip_scan_gpios(struct gpio_chip *chip) +static int of_gpiochip_scan_gpios(struct gpio_chip *chip) { struct gpio_desc *desc = NULL; struct device_node *np; const char *name; enum gpio_lookup_flags lflags; enum gpiod_flags dflags; + int ret; for_each_available_child_of_node(chip->of_node, np) { if (!of_property_read_bool(np, "gpio-hog")) @@ -218,9 +220,12 @@ static void of_gpiochip_scan_gpios(struct gpio_chip *chip) if (IS_ERR(desc)) continue; - if (gpiod_hog(desc, name, lflags, dflags)) - continue; + ret = gpiod_hog(desc, name, lflags, dflags); + if (ret < 0) + return ret; } + + return 0; } /** @@ -442,9 +447,7 @@ int of_gpiochip_add(struct gpio_chip *chip) of_node_get(chip->of_node); - of_gpiochip_scan_gpios(chip); - - return 0; + return of_gpiochip_scan_gpios(chip); } void of_gpiochip_remove(struct gpio_chip *chip)
If GPIO hog configuration failed while adding OF based gpiochip() then return the error instead of ignoring it. This helps of properly handling the gpio driver dependency. When adding the gpio hog nodes for NVIDIA's Tegra210 platforms, the gpio_hogd() fails with EPROBE_DEFER because pinctrl is not ready at this time and gpio_request() for Tegra GPIO driver returns error. The error was not causing the Tegra GPIO driver to fail as the error was getting ignored. Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com> Cc: Benoit Parrot <bparrot@ti.com> Cc: Alexandre Courbot <acourbot@nvidia.com> --- drivers/gpio/gpiolib-of.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-)