[v3,5/6] gpiolib: consolidate GPIO lookups

Message ID 20221031-gpiolib-swnode-v3-5-0282162b0fa4@gmail.com
State New
Headers
Series Add support for software nodes to gpiolib |

Commit Message

Dmitry Torokhov Nov. 9, 2022, 7:30 p.m. UTC
  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>
---
 drivers/gpio/gpiolib-acpi.c |  39 ---------
 drivers/gpio/gpiolib-acpi.h |  10 ---
 drivers/gpio/gpiolib.c      | 204 +++++++++++++++++---------------------------
 3 files changed, 76 insertions(+), 177 deletions(-)
  

Comments

Andy Shevchenko Nov. 10, 2022, 2:13 p.m. UTC | #1
On Wed, Nov 09, 2022 at 11:30:43AM -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.

...

> +	if (!IS_ERR_OR_NULL(fwnode))

As pointed earlier I still think this is not needed. Even for the sake of
showing an intent, the not-found fwnode(i.e. GPIO), will be handled anyway...

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

...here by gpiod_not_found() which is an exact intention in both cases above
(fwnode is not provided / invalid or GPIO wasn't found).


With this addressed
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
  
Dmitry Torokhov Nov. 10, 2022, 5:24 p.m. UTC | #2
On Thu, Nov 10, 2022 at 04:13:57PM +0200, Andy Shevchenko wrote:
> On Wed, Nov 09, 2022 at 11:30:43AM -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.
> 
> ...
> 
> > +	if (!IS_ERR_OR_NULL(fwnode))
> 
> As pointed earlier I still think this is not needed. Even for the sake of
> showing an intent, the not-found fwnode(i.e. GPIO), will be handled anyway...
> 
> > +		desc = gpiod_find_by_fwnode(fwnode, consumer, con_id, idx,
> > +					    &flags, &lookupflags);
> > +
> > +	if (gpiod_not_found(desc) && platform_lookup_allowed) {
> 
> ...here by gpiod_not_found() which is an exact intention in both cases above
> (fwnode is not provided / invalid or GPIO wasn't found).

Thank you for the thorough reviews.

I think at this point I will leave to to Bart and Linus to decide what
form they prefer here. From the execution point there is no practical
difference, it is all syntactic sugar.

Thanks.
  

Patch

diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
index 1bc386032ca8..bed0380c5136 100644
--- a/drivers/gpio/gpiolib-acpi.c
+++ b/drivers/gpio/gpiolib-acpi.c
@@ -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
diff --git a/drivers/gpio/gpiolib-acpi.h b/drivers/gpio/gpiolib-acpi.h
index 8880615327ac..9475f99a9694 100644
--- a/drivers/gpio/gpiolib-acpi.h
+++ b/drivers/gpio/gpiolib-acpi.h
@@ -36,10 +36,6 @@  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
@@ -61,12 +57,6 @@  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;
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index f0a7a59ac630..b1a57fdd96b6 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -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;
@@ -3801,58 +3801,84 @@  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);
 	}
@@ -3885,29 +3911,12 @@  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);
 
@@ -4061,72 +4070,11 @@  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);