From: Bartosz Golaszewski <brgl@bgdev.pl>
To: Linus Walleij <linus.walleij@linaro.org>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Johan Hovold <johan@kernel.org>
Cc: linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org,
Bartosz Golaszewski <brgl@bgdev.pl>
Subject: [PATCH v4 2/2] gpiolib: check the 'ngpios' property in core gpiolib code
Date: Thu, 2 Dec 2021 14:40:34 +0100 [thread overview]
Message-ID: <20211202134034.14048-2-brgl@bgdev.pl> (raw)
In-Reply-To: <20211202134034.14048-1-brgl@bgdev.pl>
Several drivers read the 'ngpios' device property on their own, but
since it's defined as a standard GPIO property in the device tree bindings
anyway, it's a good candidate for generalization. If the driver didn't
set its gc->ngpio, try to read the 'ngpios' property from the GPIO
device's firmware node before bailing out.
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
---
v1 -> v2:
- use device_property_read_u32() instead of fwnode_property_read_u32()
- reverse the error check logic
v2 -> v3:
- don't shadow errors other than -ENODATA in device_property_read_u32()
v3 -> v4:
- also make sure we return -EINVAL when the device 'ngpios' property is
set to 0 (thanks Andy!)
drivers/gpio/gpiolib.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index ede8b8a7aa18..bd9b8cb53476 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -599,6 +599,7 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
int base = gc->base;
unsigned int i;
int ret = 0;
+ u32 ngpios;
/*
* First: allocate and populate the internal stat container, and
@@ -646,6 +647,26 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
goto err_free_dev_name;
}
+ /*
+ * Try the device properties if the driver didn't supply the number
+ * of GPIO lines.
+ */
+ if (gc->ngpio == 0) {
+ ret = device_property_read_u32(&gdev->dev, "ngpios", &ngpios);
+ if (ret == -ENODATA)
+ /*
+ * -ENODATA means that there is no property found and
+ * we want to issue the error message to the user.
+ * Besides that, we want to return different error code
+ * to state that supplied value is not valid.
+ * */
+ ngpios = 0;
+ else if (ret)
+ goto err_free_descs;
+
+ gc->ngpio = ngpios;
+ }
+
if (gc->ngpio == 0) {
chip_err(gc, "tried to insert a GPIO chip with zero lines\n");
ret = -EINVAL;
--
2.25.1
next prev parent reply other threads:[~2021-12-02 13:40 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-02 13:40 [PATCH v4 1/2] gpiolib: improve coding style for local variables Bartosz Golaszewski
2021-12-02 13:40 ` Bartosz Golaszewski [this message]
2021-12-02 15:37 ` [PATCH v4 2/2] gpiolib: check the 'ngpios' property in core gpiolib code Andy Shevchenko
2021-12-02 15:48 ` Bartosz Golaszewski
2021-12-06 15:01 ` Bartosz Golaszewski
2021-12-06 15:01 ` [PATCH v4 1/2] gpiolib: improve coding style for local variables Bartosz Golaszewski
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