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gpiolib: consolidate GPIO lookups
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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.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
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Dmitry Torokhov authored and Bartosz Golaszewski committed Nov 15, 2022
1 parent b7452d6 commit 8eb1f71
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Showing 3 changed files with 76 additions and 177 deletions.
39 changes: 0 additions & 39 deletions drivers/gpio/gpiolib-acpi.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1024,45 +1024,6 @@ struct gpio_desc *acpi_find_gpio(struct fwnode_handle *fwnode,
return desc;
}

/**
* acpi_node_get_gpiod() - get a GPIO descriptor from ACPI resources
* @fwnode: pointer to an ACPI firmware node to get the GPIO information from
* @propname: Property name of the GPIO
* @index: index of GpioIo/GpioInt resource (starting from %0)
* @lflags: bitmask of gpio_lookup_flags GPIO_* values
* @dflags: gpiod initialization flags
*
* If @fwnode is an ACPI device object, call acpi_get_gpiod_by_index() for it.
* Otherwise (i.e. it is a data-only non-device object), use the property-based
* GPIO lookup to get to the GPIO resource with the relevant information and use
* that to obtain the GPIO descriptor to return.
*
* If the GPIO cannot be translated or there is an error an ERR_PTR is
* returned.
*/
struct gpio_desc *acpi_node_get_gpiod(struct fwnode_handle *fwnode,
const char *propname, int index,
unsigned long *lflags,
enum gpiod_flags *dflags)
{
struct acpi_gpio_info info;
struct acpi_device *adev;
struct gpio_desc *desc;

adev = to_acpi_device_node(fwnode);
if (adev)
desc = acpi_get_gpiod_by_index(adev, propname, index, &info);
else
desc = acpi_get_gpiod_from_data(fwnode, propname, index, &info);

if (!IS_ERR(desc)) {
acpi_gpio_update_gpiod_flags(dflags, &info);
acpi_gpio_update_gpiod_lookup_flags(lflags, &info);
}

return desc;
}

/**
* acpi_dev_gpio_irq_wake_get_by() - Find GpioInt and translate it to Linux IRQ number
* @adev: pointer to a ACPI device to get IRQ from
Expand Down
10 changes: 0 additions & 10 deletions drivers/gpio/gpiolib-acpi.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -24,10 +24,6 @@ struct gpio_desc *acpi_find_gpio(struct fwnode_handle *fwnode,
unsigned int idx,
enum gpiod_flags *dflags,
unsigned long *lookupflags);
struct gpio_desc *acpi_node_get_gpiod(struct fwnode_handle *fwnode,
const char *propname, int index,
unsigned long *lflags,
enum gpiod_flags *dflags);

int acpi_gpio_count(struct device *dev, const char *con_id);
#else
Expand All @@ -49,12 +45,6 @@ acpi_find_gpio(struct fwnode_handle *fwnode, const char *con_id,
{
return ERR_PTR(-ENOENT);
}
static inline struct gpio_desc *
acpi_node_get_gpiod(struct fwnode_handle *fwnode, const char *propname,
int index, unsigned long *lflags, enum gpiod_flags *dflags)
{
return ERR_PTR(-ENXIO);
}
static inline int acpi_gpio_count(struct device *dev, const char *con_id)
{
return -ENODEV;
Expand Down
204 changes: 76 additions & 128 deletions drivers/gpio/gpiolib.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -366,7 +366,7 @@ static int gpiochip_set_desc_names(struct gpio_chip *gc)
static int devprop_gpiochip_set_names(struct gpio_chip *chip)
{
struct gpio_device *gdev = chip->gpiodev;
struct fwnode_handle *fwnode = dev_fwnode(&gdev->dev);
const struct fwnode_handle *fwnode = dev_fwnode(&gdev->dev);
const char **names;
int ret, i;
int count;
Expand Down Expand Up @@ -3853,58 +3853,84 @@ static int platform_gpio_count(struct device *dev, const char *con_id)
return count;
}

/**
* fwnode_get_named_gpiod - obtain a GPIO from firmware node
* @fwnode: handle of the firmware node
* @propname: name of the firmware property representing the GPIO
* @index: index of the GPIO to obtain for the consumer
* @dflags: GPIO initialization flags
* @label: label to attach to the requested GPIO
*
* This function can be used for drivers that get their configuration
* from opaque firmware.
*
* The function properly finds the corresponding GPIO using whatever is the
* underlying firmware interface and then makes sure that the GPIO
* descriptor is requested before it is returned to the caller.
*
* Returns:
* On successful request the GPIO pin is configured in accordance with
* provided @dflags.
*
* In case of error an ERR_PTR() is returned.
*/
static struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode,
const char *propname, int index,
enum gpiod_flags dflags,
const char *label)
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);
int ret;
struct gpio_desc *desc = ERR_PTR(-ENOENT);

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 DT '%pfw' for '%s' GPIO lookup\n",
fwnode, con_id);
desc = of_find_gpio(to_of_node(fwnode), con_id, idx, lookupflags);
} else if (is_acpi_node(fwnode)) {
desc = acpi_node_get_gpiod(fwnode, propname, index,
&lflags, &dflags);
if (IS_ERR(desc))
return desc;
} else {
return ERR_PTR(-EINVAL);
dev_dbg(consumer, "using ACPI '%pfw' for '%s' GPIO lookup\n",
fwnode, con_id);
desc = acpi_find_gpio(fwnode, con_id, idx, flags, lookupflags);
}

/* Currently only ACPI takes this path */
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);
unsigned long lookupflags;
int ret;

if (!IS_ERR_OR_NULL(fwnode))
desc = gpiod_find_by_fwnode(fwnode, consumer, con_id, idx,
&flags, &lookupflags);

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)
return ERR_PTR(ret);
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);
return desc;
}

ret = gpiod_configure_flags(desc, propname, lflags, dflags);
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);
}
Expand Down Expand Up @@ -3937,29 +3963,12 @@ static struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode,
* In case of error an ERR_PTR() is returned.
*/
struct gpio_desc *fwnode_gpiod_get_index(struct fwnode_handle *fwnode,
const char *con_id, int index,
const char *con_id,
int index,
enum gpiod_flags flags,
const char *label)
{
struct gpio_desc *desc;
char prop_name[32]; /* 32 is max size of property name */
unsigned int i;

for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
if (con_id)
snprintf(prop_name, sizeof(prop_name), "%s-%s",
con_id, gpio_suffixes[i]);
else
snprintf(prop_name, sizeof(prop_name), "%s",
gpio_suffixes[i]);

desc = fwnode_get_named_gpiod(fwnode, prop_name, index, flags,
label);
if (!gpiod_not_found(desc))
break;
}

return desc;
return gpiod_find_and_request(NULL, fwnode, con_id, index, flags, label, false);
}
EXPORT_SYMBOL_GPL(fwnode_gpiod_get_index);

Expand Down Expand Up @@ -4113,72 +4122,11 @@ struct gpio_desc *__must_check gpiod_get_index(struct device *dev,
unsigned int idx,
enum gpiod_flags flags)
{
unsigned long lookupflags = GPIO_LOOKUP_FLAGS_DEFAULT;
struct gpio_desc *desc = NULL;
int ret;
/* Maybe we have a device name, maybe not */
const char *devname = dev ? dev_name(dev) : "?";
struct fwnode_handle *fwnode = dev ? dev_fwnode(dev) : NULL;
const char *devname = dev ? dev_name(dev) : "?";
const char *label = con_id ?: devname;

dev_dbg(dev, "GPIO lookup for consumer %s\n", con_id);

/* Using device tree? */
if (is_of_node(fwnode)) {
dev_dbg(dev, "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)) {
dev_dbg(dev, "using ACPI for GPIO lookup\n");
desc = acpi_find_gpio(fwnode,
con_id, idx, &flags, &lookupflags);
}

/*
* 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.
*/
if (!desc || gpiod_not_found(desc)) {
dev_dbg(dev, "using lookup tables for GPIO lookup\n");
desc = gpiod_find(dev, con_id, idx, &lookupflags);
}

if (IS_ERR(desc)) {
dev_dbg(dev, "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, con_id ?: devname);
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(dev, "nonexclusive access to GPIO for %s\n", con_id ?: devname);
return desc;
}

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

blocking_notifier_call_chain(&desc->gdev->notifier,
GPIOLINE_CHANGED_REQUESTED, desc);

return desc;
return gpiod_find_and_request(dev, fwnode, con_id, idx, flags, label, true);
}
EXPORT_SYMBOL_GPL(gpiod_get_index);

Expand Down

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