Re: [PATCH v2 5/6] gpiolib: consolidate GPIO lookups

Andy Shevchenko
2022-11-09T11:25:17Z

On Tue, Nov 08, 2022 at 04:26:50PM -0800, Dmitry Torokhov wrote:
> Ensure that all paths to obtain/look up GPIOD from generic
> consumer-visible APIs go through the new gpiod_find_and_request()
> helper, so that we can easily extend it with support for new firmware
> mechanisms.
>
> The only exception is OF-specific [devm_]gpiod_get_from_of_node() API
> that is still being used by a couple of drivers and will be removed as
> soon as patches converting them to use generic fwnode/device APIs are
> accepted.

...

> +static struct gpio_desc *gpiod_find_by_fwnode(struct fwnode_handle *fwnode,
> + struct device *consumer,
> + const char *con_id,
> + unsigned int idx,
> + enum gpiod_flags *flags,
> + unsigned long *lookupflags)
> {
> - unsigned long lflags = GPIO_LOOKUP_FLAGS_DEFAULT;

> - struct gpio_desc *desc = ERR_PTR(-ENODEV);

Not sure why this is needed. Now I see that else branch has been changed,
but looking closer to it, we can drop it completely, while leaving this
line untouched, correct?

> - int ret;
> + struct gpio_desc *desc;
>
> + dev_dbg(consumer, "GPIO lookup for consumer %s in node '%pfw'\n",
> + con_id, fwnode);
> +
> + /* Using device tree? */
> if (is_of_node(fwnode)) {
> - desc = gpiod_get_from_of_node(to_of_node(fwnode),
> - propname, index,
> - dflags,
> - label);
> - return desc;
> + dev_dbg(consumer, "using device tree for GPIO lookup\n");
> + desc = of_find_gpio(to_of_node(fwnode),
> + con_id, idx, lookupflags);

At least con_id can be placed on the previous line.

> } else if (is_acpi_node(fwnode)) {
> - desc = acpi_node_get_gpiod(fwnode, propname, index,
> - &lflags, &dflags);
> - if (IS_ERR(desc))
> - return desc;
> + dev_dbg(consumer, "using ACPI for GPIO lookup\n");
> + desc = acpi_find_gpio(fwnode, con_id, idx, flags, lookupflags);
> } else {
> - return ERR_PTR(-EINVAL);
> + desc = ERR_PTR(-ENOENT);
> }
>
> - /* Currently only ACPI takes this path */
> + return desc;
> +}

...

> + struct gpio_desc *desc = ERR_PTR(-ENOENT);
> + unsigned long lookupflags;
> + int ret;

> + if (!IS_ERR_OR_NULL(fwnode))

I think this is superfluous check.

Now in the form of this series, you have only a single dev_dbg() that tries to
dereference it. Do we really need to have it there, since every branch has its
own dev_dbg() anyway?

> + desc = gpiod_find_by_fwnode(fwnode, consumer, con_id, idx,
> + &flags, &lookupflags);

> +

This blank line can be dropped after addressing above.

> + if (gpiod_not_found(desc) && platform_lookup_allowed) {
> + /*
> + * Either we are not using DT or ACPI, or their lookup did not
> + * return a result. In that case, use platform lookup as a
> + * fallback.
> + */
> + dev_dbg(consumer, "using lookup tables for GPIO lookup\n");
> + desc = gpiod_find(consumer, con_id, idx, &lookupflags);
> + }
> +
> + if (IS_ERR(desc)) {
> + dev_dbg(consumer, "No GPIO consumer %s found\n", con_id);
> + return desc;
> + }

...

> + return gpiod_find_and_request(NULL, fwnode, con_id, index, flags, label,
> + false);

One line?

...

> + return gpiod_find_and_request(dev, fwnode, con_id, idx, flags, label,
> + true);

One line?

--
With Best Regards,
Andy Shevchenko