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

Andy Shevchenko
2022-11-04T17:17:54Z

On Thu, Nov 03, 2022 at 11:10:15PM -0700, 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.

...

> +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)
> {

> + struct gpio_desc *desc = ERR_PTR(-ENOENT);

No need, just return directly.

> + dev_dbg(consumer, "GPIO lookup for consumer %s in node '%s'\n",
> + con_id, fwnode_get_name(fwnode));

%pfwP ?

> +
> + /* Using device tree? */
> if (is_of_node(fwnode)) {
> + dev_dbg(consumer, "using device tree for GPIO lookup\n");
> + desc = of_find_gpio(to_of_node(fwnode),
> + con_id, idx, lookupflags);
> } else if (is_acpi_node(fwnode)) {

With direct return, no need for 'else' here.

> + dev_dbg(consumer, "using ACPI for GPIO lookup\n");
> + desc = acpi_find_gpio(fwnode, con_id, idx, flags, lookupflags);
> }
>
> + return desc;
> +}

...

> +static struct gpio_desc *gpiod_find_and_request(struct device *consumer,
> + struct fwnode_handle *fwnode,
> + const char *con_id,
> + unsigned int idx,
> + enum gpiod_flags flags,
> + const char *label,
> + bool platform_lookup_allowed)
> +{

> + struct gpio_desc *desc = ERR_PTR(-ENOENT);

We can get rid of the assignment, see below.

> + unsigned long lookupflags;
> + int ret;

> + if (fwnode)

Do we need this check?

Debug message above (when %pfw is used) would be even useful when
fwnode == NULL.

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

> +

The blank line can be removed after above comments being addressed.

> + 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;
> + }
> +
> + /*
> + * If a connection label was passed use that, else attempt to use
> + * the device name as label
> + */
> ret = gpiod_request(desc, label);
> + if (ret) {
> + if (!(ret == -EBUSY && flags & GPIOD_FLAGS_BIT_NONEXCLUSIVE))
> + return ERR_PTR(ret);
> +
> + /*
> + * This happens when there are several consumers for
> + * the same GPIO line: we just return here without
> + * further initialization. It is a bit of a hack.
> + * This is necessary to support fixed regulators.
> + *
> + * FIXME: Make this more sane and safe.
> + */

> + dev_info(consumer,
> + "nonexclusive access to GPIO for %s\n", con_id);

Cam be one line.

> + return desc;
> + }
>
> + ret = gpiod_configure_flags(desc, con_id, lookupflags, flags);
> if (ret < 0) {
> + dev_dbg(consumer, "setup of GPIO %s failed\n", con_id);
> gpiod_put(desc);
> return ERR_PTR(ret);
> }

...

> struct gpio_desc *fwnode_gpiod_get_index(struct fwnode_handle *fwnode,
> + const char *con_id,
> + int index,
> enum gpiod_flags flags,
> const char *label)
> {
>

Unnecessary blank line?

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

Can be one line.

> }

...

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

Ditto.

--
With Best Regards,
Andy Shevchenko