Re: [PATCH v8 2/4] pinctrl: cygnus: add gpio/pinconf driver

Dmitry Torokhov
2015-02-09T19:20:27Z

Hi Ray,

On Wed, Feb 04, 2015 at 09:21:01AM -0800, Ray Jui wrote:
> +static int cygnus_gpio_pinmux_add_range(struct cygnus_gpio *chip)
> +{
> + struct device_node *node = chip->dev->of_node;
> + struct device_node *pinmux_node;
> + struct platform_device *pinmux_pdev;
> + struct gpio_chip *gc = &chip->gc;
> + int i, ret;
> +
> + /* parse DT to find the phandle to the pinmux controller */
> + pinmux_node = of_parse_phandle(node, "pinmux", 0);
> + if (!pinmux_node)
> + return -ENODEV;
> +
> + pinmux_pdev = of_find_device_by_node(pinmux_node);
> + if (!pinmux_pdev) {
> + dev_err(chip->dev, "failed to get pinmux device\n");
> + return -EINVAL;
> + }
> +
> + /* now need to create the mapping between local GPIO and PINMUX pins */
> + for (i = 0; i < ARRAY_SIZE(cygnus_gpio_pintable); i++) {
> + ret = gpiochip_add_pin_range(gc, dev_name(&pinmux_pdev->dev),
> + cygnus_gpio_pintable[i].offset,
> + cygnus_gpio_pintable[i].pin_base,
> + cygnus_gpio_pintable[i].num_pins);
> + if (ret) {
> + dev_err(chip->dev, "unable to add GPIO pin range\n");
> + goto err_put_device;
> + }
> + }
> +
> + chip->pinmux_is_supported = true;
> +
> + /* no need for pinmux_pdev device reference anymore */
> + put_device(&pinmux_pdev->dev);

Sorry I did not notice it before, but of_parse_phandle() takes reference
to the returned device node, so you need to "put" it here and in error
path as well. Actually you can do:

int ret = 0;

pinmux_node = of_parse_phandle(node, "pinmux", 0);
if (!pinmux_node)
return -ENODEV;

pinmux_pdev = of_find_device_by_node(pinmux_node);
/* We do not longer need pinmux node */
of_node_put(pinmux_node);

if (!pinmux_dev)
....

for (..) {
...
if (ret) {
dev_err(...);
break;
}
}

chip->pinmux_is_supported = (ret == 0);
put_device(..);
return ret;
}

This way you free resources in the same path.

...

> +
> +static struct platform_driver cygnus_gpio_driver = {
> + .driver = {
> + .name = "cygnus-gpio",
> + .of_match_table = cygnus_gpio_of_match,
> + .suppress_bind_attrs = true,
> + },
> + .probe = cygnus_gpio_probe,
> +};
> +
> +static int __init cygnus_gpio_init(void)
> +{
> + return platform_driver_probe(&cygnus_gpio_driver, cygnus_gpio_probe);

When I asked you to add ".suppress_bind_attrs = true" I missed the fact
that you were using platform_driver_probe() which already does this
internally. However platform_driver_probe() can't handle deferred
probing, which may or may not be OK. Is there a chance that any of the
resources needed by the driver return -EPROBE_DEFER? If not then it is
safe to continue using platform_driver_probe() and you can drop
suppress_bind_attrs assignment, otherwise it may be better to switch to
platform_driver_register().

Thanks.

--
Dmitry