Merge tag 'gpio-v4.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio

Pull GPIO updates from Linus Walleij:
 "The is the bulk of GPIO changes for the v4.16 kernel cycle. It is
  pretty calm this time around I think. I even got time to get to things
  like starting to clean up header includes.

  Core changes:

   - Disallow open drain and open source flags to be set simultaneously.
     This doesn't make electrical sense, and would the hardware actually
     respond to this setting, the result would be short circuit.

   - ACPI GPIO has a new core infrastructure for handling quirks. The
     quirks are there to deal with broken ACPI tables centrally instead
     of pushing the work to individual drivers. In the world of BIOS
     writers, the ACPI tables are perfect. Until they find a mistake in
     it. When such a mistake is found, we can patch it with a quirk. It
     should never happen, the problem is that it happens. So we
     accomodate for it.

   - Several documentation updates.

   - Revert the patch setting up initial direction state from reading
     the device. This was causing bad things for drivers that can't read
     status on all its pins. It is only affecting debugfs information
     quality.

   - Label descriptors with the device name if no explicit label is
     passed in.

   - Pave the ground for transitioning SPI and regulators to use GPIO
     descriptors by implementing some quirks in the device tree GPIO
     parsing code.

  New drivers:

   - New driver for the Access PCIe IDIO 24 family.

  Other:

   - Major refactorings and improvements to the GPIO mockup driver used
     for test and verification.

   - Moved the AXP209 driver over to pin control since it gained a pin
     control back-end. These patches will appear (with the same hashes)
     in the pin control pull request as well.

   - Convert the onewire GPIO driver w1-gpio to use descriptors. This is
     merged here since the W1 maintainers send very few pull requests
     and he ACKed it.

   - Start to clean up driver headers using <linux/gpio.h> to just use
     <linux/gpio/driver.h> as appropriate"

* tag 'gpio-v4.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio: (103 commits)
  gpio: Timestamp events in hardirq handler
  gpio: Fix kernel stack leak to userspace
  gpio: Fix a documentation spelling mistake
  gpio: Documentation update
  gpiolib: remove redundant initialization of pointer desc
  gpio: of: Fix NPE from OF flags
  gpio: stmpe: Delete an unnecessary variable initialisation in stmpe_gpio_probe()
  gpio: stmpe: Move an assignment in stmpe_gpio_probe()
  gpio: stmpe: Improve a size determination in stmpe_gpio_probe()
  gpio: stmpe: Use seq_putc() in stmpe_dbg_show()
  gpio: No NULL owner
  gpio: stmpe: i2c transfer are forbiden in atomic context
  gpio: davinci: Include proper header
  gpio: da905x: Include proper header
  gpio: cs5535: Include proper header
  gpio: crystalcove: Include proper header
  gpio: bt8xx: Include proper header
  gpio: bcm-kona: Include proper header
  gpio: arizona: Include proper header
  gpio: amd8111: Include proper header
  ...

1 files changed, 223 insertions, 107 deletions

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 5d6e8bb38ac7..36ca5064486e 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -162,7 +162,7 @@ EXPORT_SYMBOL_GPL(desc_to_gpio);
  */
 struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc)
 {
-	if (!desc || !desc->gdev || !desc->gdev->chip)
+	if (!desc || !desc->gdev)
 		return NULL;
 	return desc->gdev->chip;
 }
@@ -196,7 +196,7 @@ static int gpiochip_find_base(int ngpio)
  * gpiod_get_direction - return the current direction of a GPIO
  * @desc:	GPIO to get the direction of
  *
- * Return GPIOF_DIR_IN or GPIOF_DIR_OUT, or an error code in case of error.
+ * Returns 0 for output, 1 for input, or an error code in case of error.
  *
  * This function may sleep if gpiod_cansleep() is true.
  */
@@ -460,6 +460,15 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip)
 	if (lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS)
 		return -EINVAL;
 
+	/*
+	 * Do not allow OPEN_SOURCE & OPEN_DRAIN flags in a single request. If
+	 * the hardware actually supports enabling both at the same time the
+	 * electrical result would be disastrous.
+	 */
+	if ((lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) &&
+	    (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
+		return -EINVAL;
+
 	/* OPEN_DRAIN and OPEN_SOURCE flags only make sense for output mode. */
 	if (!(lflags & GPIOHANDLE_REQUEST_OUTPUT) &&
 	    ((lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
@@ -506,6 +515,10 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip)
 		if (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE)
 			set_bit(FLAG_OPEN_SOURCE, &desc->flags);
 
+		ret = gpiod_set_transitory(desc, false);
+		if (ret < 0)
+			goto out_free_descs;
+
 		/*
 		 * Lines have to be requested explicitly for input
 		 * or output, else the line will be treated "as is".
@@ -588,6 +601,9 @@ out_free_lh:
  * @events: KFIFO for the GPIO events
  * @read_lock: mutex lock to protect reads from colliding with adding
  * new events to the FIFO
+ * @timestamp: cache for the timestamp storing it between hardirq
+ * and IRQ thread, used to bring the timestamp close to the actual
+ * event
  */
 struct lineevent_state {
 	struct gpio_device *gdev;
@@ -598,6 +614,7 @@ struct lineevent_state {
 	wait_queue_head_t wait;
 	DECLARE_KFIFO(events, struct gpioevent_data, 16);
 	struct mutex read_lock;
+	u64 timestamp;
 };
 
 #define GPIOEVENT_REQUEST_VALID_FLAGS \
@@ -732,7 +749,10 @@ static irqreturn_t lineevent_irq_thread(int irq, void *p)
 	struct gpioevent_data ge;
 	int ret, level;
 
-	ge.timestamp = ktime_get_real_ns();
+	/* Do not leak kernel stack to userspace */
+	memset(&ge, 0, sizeof(ge));
+
+	ge.timestamp = le->timestamp;
 	level = gpiod_get_value_cansleep(le->desc);
 
 	if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE
@@ -760,6 +780,19 @@ static irqreturn_t lineevent_irq_thread(int irq, void *p)
 	return IRQ_HANDLED;
 }
 
+static irqreturn_t lineevent_irq_handler(int irq, void *p)
+{
+	struct lineevent_state *le = p;
+
+	/*
+	 * Just store the timestamp in hardirq context so we get it as
+	 * close in time as possible to the actual event.
+	 */
+	le->timestamp = ktime_get_real_ns();
+
+	return IRQ_WAKE_THREAD;
+}
+
 static int lineevent_create(struct gpio_device *gdev, void __user *ip)
 {
 	struct gpioevent_request eventreq;
@@ -852,7 +885,7 @@ static int lineevent_create(struct gpio_device *gdev, void __user *ip)
 
 	/* Request a thread to read the events */
 	ret = request_threaded_irq(le->irq,
-			NULL,
+			lineevent_irq_handler,
 			lineevent_irq_thread,
 			irqflags,
 			le->label,
@@ -1050,7 +1083,7 @@ static void gpiodevice_release(struct device *dev)
 
 	list_del(&gdev->list);
 	ida_simple_remove(&gpio_ida, gdev->id);
-	kfree(gdev->label);
+	kfree_const(gdev->label);
 	kfree(gdev->descs);
 	kfree(gdev);
 }
@@ -1159,10 +1192,7 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data,
 		goto err_free_descs;
 	}
 
-	if (chip->label)
-		gdev->label = kstrdup(chip->label, GFP_KERNEL);
-	else
-		gdev->label = kstrdup("unknown", GFP_KERNEL);
+	gdev->label = kstrdup_const(chip->label ?: "unknown", GFP_KERNEL);
 	if (!gdev->label) {
 		status = -ENOMEM;
 		goto err_free_descs;
@@ -1209,31 +1239,14 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data,
 		struct gpio_desc *desc = &gdev->descs[i];
 
 		desc->gdev = gdev;
-		/*
-		 * REVISIT: most hardware initializes GPIOs as inputs
-		 * (often with pullups enabled) so power usage is
-		 * minimized. Linux code should set the gpio direction
-		 * first thing; but until it does, and in case
-		 * chip->get_direction is not set, we may expose the
-		 * wrong direction in sysfs.
-		 */
 
-		if (chip->get_direction) {
-			/*
-			 * If we have .get_direction, set up the initial
-			 * direction flag from the hardware.
-			 */
-			int dir = chip->get_direction(chip, i);
-
-			if (!dir)
-				set_bit(FLAG_IS_OUT, &desc->flags);
-		} else if (!chip->direction_input) {
-			/*
-			 * If the chip lacks the .direction_input callback
-			 * we logically assume all lines are outputs.
-			 */
-			set_bit(FLAG_IS_OUT, &desc->flags);
-		}
+		/* REVISIT: most hardware initializes GPIOs as inputs (often
+		 * with pullups enabled) so power usage is minimized. Linux
+		 * code should set the gpio direction first thing; but until
+		 * it does, and in case chip->get_direction is not set, we may
+		 * expose the wrong direction in sysfs.
+		 */
+		desc->flags = !chip->direction_input ? (1 << FLAG_IS_OUT) : 0;
 	}
 
 #ifdef CONFIG_PINCTRL
@@ -1283,7 +1296,7 @@ err_remove_from_list:
 	list_del(&gdev->list);
 	spin_unlock_irqrestore(&gpio_lock, flags);
 err_free_label:
-	kfree(gdev->label);
+	kfree_const(gdev->label);
 err_free_descs:
 	kfree(gdev->descs);
 err_free_gdev:
@@ -1383,7 +1396,7 @@ static int devm_gpio_chip_match(struct device *dev, void *res, void *data)
 }
 
 /**
- * devm_gpiochip_add_data() - Resource manager piochip_add_data()
+ * devm_gpiochip_add_data() - Resource manager gpiochip_add_data()
  * @dev: the device pointer on which irq_chip belongs to.
  * @chip: the chip to register, with chip->base initialized
  * @data: driver-private data associated with this chip
@@ -1510,14 +1523,15 @@ static void gpiochip_irqchip_free_valid_mask(struct gpio_chip *gpiochip)
 	gpiochip->irq.valid_mask = NULL;
 }
 
-static bool gpiochip_irqchip_irq_valid(const struct gpio_chip *gpiochip,
-				       unsigned int offset)
+bool gpiochip_irqchip_irq_valid(const struct gpio_chip *gpiochip,
+				unsigned int offset)
 {
 	/* No mask means all valid */
 	if (likely(!gpiochip->irq.valid_mask))
 		return true;
 	return test_bit(offset, gpiochip->irq.valid_mask);
 }
+EXPORT_SYMBOL_GPL(gpiochip_irqchip_irq_valid);
 
 /**
  * gpiochip_set_cascaded_irqchip() - connects a cascaded irqchip to a gpiochip
@@ -2174,40 +2188,37 @@ done:
  * macro to avoid endless duplication. If the desc is NULL it is an
  * optional GPIO and calls should just bail out.
  */
+static int validate_desc(const struct gpio_desc *desc, const char *func)
+{
+	if (!desc)
+		return 0;
+	if (IS_ERR(desc)) {
+		pr_warn("%s: invalid GPIO (errorpointer)\n", func);
+		return PTR_ERR(desc);
+	}
+	if (!desc->gdev) {
+		pr_warn("%s: invalid GPIO (no device)\n", func);
+		return -EINVAL;
+	}
+	if (!desc->gdev->chip) {
+		dev_warn(&desc->gdev->dev,
+			 "%s: backing chip is gone\n", func);
+		return 0;
+	}
+	return 1;
+}
+
 #define VALIDATE_DESC(desc) do { \
-	if (!desc) \
-		return 0; \
-	if (IS_ERR(desc)) {						\
-		pr_warn("%s: invalid GPIO (errorpointer)\n", __func__); \
-		return PTR_ERR(desc); \
-	} \
-	if (!desc->gdev) { \
-		pr_warn("%s: invalid GPIO (no device)\n", __func__); \
-		return -EINVAL; \
-	} \
-	if ( !desc->gdev->chip ) { \
-		dev_warn(&desc->gdev->dev, \
-			 "%s: backing chip is gone\n", __func__); \
-		return 0; \
-	} } while (0)
+	int __valid = validate_desc(desc, __func__); \
+	if (__valid <= 0) \
+		return __valid; \
+	} while (0)
 
 #define VALIDATE_DESC_VOID(desc) do { \
-	if (!desc) \
-		return; \
-	if (IS_ERR(desc)) {						\
-		pr_warn("%s: invalid GPIO (errorpointer)\n", __func__); \
-		return; \
-	} \
-	if (!desc->gdev) { \
-		pr_warn("%s: invalid GPIO (no device)\n", __func__); \
-		return; \
-	} \
-	if (!desc->gdev->chip) { \
-		dev_warn(&desc->gdev->dev, \
-			 "%s: backing chip is gone\n", __func__); \
+	int __valid = validate_desc(desc, __func__); \
+	if (__valid <= 0) \
 		return; \
-	} } while (0)
-
+	} while (0)
 
 int gpiod_request(struct gpio_desc *desc, const char *label)
 {
@@ -2456,7 +2467,7 @@ EXPORT_SYMBOL_GPL(gpiod_direction_output_raw);
  */
 int gpiod_direction_output(struct gpio_desc *desc, int value)
 {
-	struct gpio_chip *gc = desc->gdev->chip;
+	struct gpio_chip *gc;
 	int ret;
 
 	VALIDATE_DESC(desc);
@@ -2473,6 +2484,7 @@ int gpiod_direction_output(struct gpio_desc *desc, int value)
 		return -EIO;
 	}
 
+	gc = desc->gdev->chip;
 	if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) {
 		/* First see if we can enable open drain in hardware */
 		ret = gpio_set_drive_single_ended(gc, gpio_chip_hwgpio(desc),
@@ -2530,6 +2542,50 @@ int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce)
 EXPORT_SYMBOL_GPL(gpiod_set_debounce);
 
 /**
+ * gpiod_set_transitory - Lose or retain GPIO state on suspend or reset
+ * @desc: descriptor of the GPIO for which to configure persistence
+ * @transitory: True to lose state on suspend or reset, false for persistence
+ *
+ * Returns:
+ * 0 on success, otherwise a negative error code.
+ */
+int gpiod_set_transitory(struct gpio_desc *desc, bool transitory)
+{
+	struct gpio_chip *chip;
+	unsigned long packed;
+	int gpio;
+	int rc;
+
+	VALIDATE_DESC(desc);
+	/*
+	 * Handle FLAG_TRANSITORY first, enabling queries to gpiolib for
+	 * persistence state.
+	 */
+	if (transitory)
+		set_bit(FLAG_TRANSITORY, &desc->flags);
+	else
+		clear_bit(FLAG_TRANSITORY, &desc->flags);
+
+	/* If the driver supports it, set the persistence state now */
+	chip = desc->gdev->chip;
+	if (!chip->set_config)
+		return 0;
+
+	packed = pinconf_to_config_packed(PIN_CONFIG_PERSIST_STATE,
+					  !transitory);
+	gpio = gpio_chip_hwgpio(desc);
+	rc = chip->set_config(chip, gpio, packed);
+	if (rc == -ENOTSUPP) {
+		dev_dbg(&desc->gdev->dev, "Persistence not supported for GPIO %d\n",
+				gpio);
+		return 0;
+	}
+
+	return rc;
+}
+EXPORT_SYMBOL_GPL(gpiod_set_transitory);
+
+/**
  * gpiod_is_active_low - test whether a GPIO is active-low or not
  * @desc: the gpio descriptor to test
  *
@@ -3129,8 +3185,7 @@ bool gpiochip_line_is_persistent(struct gpio_chip *chip, unsigned int offset)
 	if (offset >= chip->ngpio)
 		return false;
 
-	return !test_bit(FLAG_SLEEP_MAY_LOSE_VALUE,
-			 &chip->gpiodev->descs[offset].flags);
+	return !test_bit(FLAG_TRANSITORY, &chip->gpiodev->descs[offset].flags);
 }
 EXPORT_SYMBOL_GPL(gpiochip_line_is_persistent);
 
@@ -3565,8 +3620,10 @@ int gpiod_configure_flags(struct gpio_desc *desc, const char *con_id,
 
 	if (lflags & GPIO_OPEN_SOURCE)
 		set_bit(FLAG_OPEN_SOURCE, &desc->flags);
-	if (lflags & GPIO_SLEEP_MAY_LOSE_VALUE)
-		set_bit(FLAG_SLEEP_MAY_LOSE_VALUE, &desc->flags);
+
+	status = gpiod_set_transitory(desc, (lflags & GPIO_TRANSITORY));
+	if (status < 0)
+		return status;
 
 	/* No particular flag request, return here... */
 	if (!(dflags & GPIOD_FLAGS_BIT_DIR_SET)) {
@@ -3606,6 +3663,8 @@ struct gpio_desc *__must_check gpiod_get_index(struct device *dev,
 	struct gpio_desc *desc = NULL;
 	int status;
 	enum gpio_lookup_flags lookupflags = 0;
+	/* Maybe we have a device name, maybe not */
+	const char *devname = dev ? dev_name(dev) : "?";
 
 	dev_dbg(dev, "GPIO lookup for consumer %s\n", con_id);
 
@@ -3634,7 +3693,11 @@ struct gpio_desc *__must_check gpiod_get_index(struct device *dev,
 		return desc;
 	}
 
-	status = gpiod_request(desc, con_id);
+	/*
+	 * If a connection label was passed use that, else attempt to use
+	 * the device name as label
+	 */
+	status = gpiod_request(desc, con_id ? con_id : devname);
 	if (status < 0)
 		return ERR_PTR(status);
 
@@ -3650,17 +3713,88 @@ struct gpio_desc *__must_check gpiod_get_index(struct device *dev,
 EXPORT_SYMBOL_GPL(gpiod_get_index);
 
 /**
+ * gpiod_get_from_of_node() - obtain a GPIO from an OF node
+ * @node:	handle of the OF node
+ * @propname:	name of the DT 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
+ *
+ * Returns:
+ * On successful request the GPIO pin is configured in accordance with
+ * provided @dflags. If the node does not have the requested GPIO
+ * property, NULL is returned.
+ *
+ * In case of error an ERR_PTR() is returned.
+ */
+struct gpio_desc *gpiod_get_from_of_node(struct device_node *node,
+					 const char *propname, int index,
+					 enum gpiod_flags dflags,
+					 const char *label)
+{
+	struct gpio_desc *desc;
+	unsigned long lflags = 0;
+	enum of_gpio_flags flags;
+	bool active_low = false;
+	bool single_ended = false;
+	bool open_drain = false;
+	bool transitory = false;
+	int ret;
+
+	desc = of_get_named_gpiod_flags(node, propname,
+					index, &flags);
+
+	if (!desc || IS_ERR(desc)) {
+		/* If it is not there, just return NULL */
+		if (PTR_ERR(desc) == -ENOENT)
+			return NULL;
+		return desc;
+	}
+
+	active_low = flags & OF_GPIO_ACTIVE_LOW;
+	single_ended = flags & OF_GPIO_SINGLE_ENDED;
+	open_drain = flags & OF_GPIO_OPEN_DRAIN;
+	transitory = flags & OF_GPIO_TRANSITORY;
+
+	ret = gpiod_request(desc, label);
+	if (ret)
+		return ERR_PTR(ret);
+
+	if (active_low)
+		lflags |= GPIO_ACTIVE_LOW;
+
+	if (single_ended) {
+		if (open_drain)
+			lflags |= GPIO_OPEN_DRAIN;
+		else
+			lflags |= GPIO_OPEN_SOURCE;
+	}
+
+	if (transitory)
+		lflags |= GPIO_TRANSITORY;
+
+	ret = gpiod_configure_flags(desc, propname, lflags, dflags);
+	if (ret < 0) {
+		gpiod_put(desc);
+		return ERR_PTR(ret);
+	}
+
+	return desc;
+}
+EXPORT_SYMBOL(gpiod_get_from_of_node);
+
+/**
  * 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 in the consumer
+ * @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 firmware.
+ * from opaque firmware.
  *
- * Function properly finds the corresponding GPIO using whatever is the
+ * 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.
  *
@@ -3677,53 +3811,35 @@ struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode,
 {
 	struct gpio_desc *desc = ERR_PTR(-ENODEV);
 	unsigned long lflags = 0;
-	bool active_low = false;
-	bool single_ended = false;
-	bool open_drain = false;
 	int ret;
 
 	if (!fwnode)
 		return ERR_PTR(-EINVAL);
 
 	if (is_of_node(fwnode)) {
-		enum of_gpio_flags flags;
-
-		desc = of_get_named_gpiod_flags(to_of_node(fwnode), propname,
-						index, &flags);
-		if (!IS_ERR(desc)) {
-			active_low = flags & OF_GPIO_ACTIVE_LOW;
-			single_ended = flags & OF_GPIO_SINGLE_ENDED;
-			open_drain = flags & OF_GPIO_OPEN_DRAIN;
-		}
+		desc = gpiod_get_from_of_node(to_of_node(fwnode),
+					      propname, index,
+					      dflags,
+					      label);
+		return desc;
 	} else if (is_acpi_node(fwnode)) {
 		struct acpi_gpio_info info;
 
 		desc = acpi_node_get_gpiod(fwnode, propname, index, &info);
-		if (!IS_ERR(desc)) {
-			active_low = info.polarity == GPIO_ACTIVE_LOW;
-			ret = acpi_gpio_update_gpiod_flags(&dflags, info.flags);
-			if (ret)
-				pr_debug("Override GPIO initialization flags\n");
-		}
-	}
+		if (IS_ERR(desc))
+			return desc;
 
-	if (IS_ERR(desc))
-		return desc;
+		acpi_gpio_update_gpiod_flags(&dflags, &info);
 
+		if (info.polarity == GPIO_ACTIVE_LOW)
+			lflags |= GPIO_ACTIVE_LOW;
+	}
+
+	/* Currently only ACPI takes this path */
 	ret = gpiod_request(desc, label);
 	if (ret)
 		return ERR_PTR(ret);
 
-	if (active_low)
-		lflags |= GPIO_ACTIVE_LOW;
-
-	if (single_ended) {
-		if (open_drain)
-			lflags |= GPIO_OPEN_DRAIN;
-		else
-			lflags |= GPIO_OPEN_SOURCE;
-	}
-
 	ret = gpiod_configure_flags(desc, propname, lflags, dflags);
 	if (ret < 0) {
 		gpiod_put(desc);