dm: Add GPIO support and tests

Add driver model support for GPIOs. Since existing GPIO drivers do not use
driver model, this feature must be enabled by CONFIG_DM_GPIO. After all
GPO drivers are converted over we can perhaps remove this config.

Tests are provided for the sandbox implementation, and are a sufficient
sanity check for basic operation.

The GPIO uclass understands the concept of named banks of GPIOs, with each
GPIO device providing a single bank. Within each bank the GPIOs are numbered
using an offset from 0 to n-1. For example a bank named 'b' with 20
offsets will provide GPIOs named b0 to b19.

Anonymous GPIO banks are also supported, and are just numbered without any
prefix.

Each time a GPIO driver is added to the uclass, the GPIOs are renumbered
accordinging, so there is always a global GPIO numbering order.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Pavel Herrmann <morpheus.ibis@gmail.com>
Signed-off-by: Viktor Křivák <viktor.krivak@gmail.com>
Signed-off-by: Tomas Hlavacek <tmshlvck@gmail.com>

2 files changed, 268 insertions, 0 deletions

diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index ed2c0c7..4e001e1 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -5,6 +5,8 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
+obj-$(CONFIG_DM_GPIO)		+= gpio-uclass.o
+
 obj-$(CONFIG_AT91_GPIO)	+= at91_gpio.o
 obj-$(CONFIG_INTEL_ICH6_GPIO)	+= intel_ich6_gpio.o
 obj-$(CONFIG_KIRKWOOD_GPIO)	+= kw_gpio.o
diff --git a/drivers/gpio/gpio-uclass.c b/drivers/gpio/gpio-uclass.c
new file mode 100644
index 0000000..56bfd11
--- /dev/null
+++ b/drivers/gpio/gpio-uclass.c
@@ -0,0 +1,266 @@
+/*
+ * Copyright (c) 2013 Google, Inc
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <asm/gpio.h>
+
+/**
+ * gpio_to_device() - Convert global GPIO number to device, number
+ * gpio:	The numeric representation of the GPIO
+ *
+ * Convert the GPIO number to an entry in the list of GPIOs
+ * or GPIO blocks registered with the GPIO controller. Returns
+ * entry on success, NULL on error.
+ */
+static int gpio_to_device(unsigned int gpio, struct device **devp,
+			  unsigned int *offset)
+{
+	struct gpio_dev_priv *uc_priv;
+	struct device *dev;
+	int ret;
+
+	for (ret = uclass_first_device(UCLASS_GPIO, &dev);
+	     dev;
+	     ret = uclass_next_device(&dev)) {
+		uc_priv = dev->uclass_priv;
+		if (gpio >= uc_priv->gpio_base &&
+		    gpio < uc_priv->gpio_base + uc_priv->gpio_count) {
+			*devp = dev;
+			*offset = gpio - uc_priv->gpio_base;
+			return 0;
+		}
+	}
+
+	/* No such GPIO */
+	return ret ? ret : -EINVAL;
+}
+
+int gpio_lookup_name(const char *name, struct device **devp,
+		     unsigned int *offsetp, unsigned int *gpiop)
+{
+	struct gpio_dev_priv *uc_priv;
+	struct device *dev;
+	int ret;
+
+	if (devp)
+		*devp = NULL;
+	for (ret = uclass_first_device(UCLASS_GPIO, &dev);
+	     dev;
+	     ret = uclass_next_device(&dev)) {
+		ulong offset;
+		int len;
+
+		uc_priv = dev->uclass_priv;
+		len = uc_priv->bank_name ? strlen(uc_priv->bank_name) : 0;
+
+		if (!strncmp(name, uc_priv->bank_name, len)) {
+			if (strict_strtoul(name + len, 10, &offset))
+				continue;
+			if (devp)
+				*devp = dev;
+			if (offsetp)
+				*offsetp = offset;
+			if (gpiop)
+				*gpiop = uc_priv->gpio_base + offset;
+			return 0;
+		}
+	}
+
+	return ret ? ret : -EINVAL;
+}
+
+/**
+ * gpio_request() - [COMPAT] Request GPIO
+ * gpio:	GPIO number
+ * label:	Name for the requested GPIO
+ *
+ * This function implements the API that's compatible with current
+ * GPIO API used in U-Boot. The request is forwarded to particular
+ * GPIO driver. Returns 0 on success, negative value on error.
+ */
+int gpio_request(unsigned gpio, const char *label)
+{
+	unsigned int offset;
+	struct device *dev;
+	int ret;
+
+	ret = gpio_to_device(gpio, &dev, &offset);
+	if (ret)
+		return ret;
+
+	if (!gpio_get_ops(dev)->request)
+		return 0;
+
+	return gpio_get_ops(dev)->request(dev, offset, label);
+}
+
+/**
+ * gpio_free() - [COMPAT] Relinquish GPIO
+ * gpio:	GPIO number
+ *
+ * This function implements the API that's compatible with current
+ * GPIO API used in U-Boot. The request is forwarded to particular
+ * GPIO driver. Returns 0 on success, negative value on error.
+ */
+int gpio_free(unsigned gpio)
+{
+	unsigned int offset;
+	struct device *dev;
+	int ret;
+
+	ret = gpio_to_device(gpio, &dev, &offset);
+	if (ret)
+		return ret;
+
+	if (!gpio_get_ops(dev)->free)
+		return 0;
+	return gpio_get_ops(dev)->free(dev, offset);
+}
+
+/**
+ * gpio_direction_input() - [COMPAT] Set GPIO direction to input
+ * gpio:	GPIO number
+ *
+ * This function implements the API that's compatible with current
+ * GPIO API used in U-Boot. The request is forwarded to particular
+ * GPIO driver. Returns 0 on success, negative value on error.
+ */
+int gpio_direction_input(unsigned gpio)
+{
+	unsigned int offset;
+	struct device *dev;
+	int ret;
+
+	ret = gpio_to_device(gpio, &dev, &offset);
+	if (ret)
+		return ret;
+
+	return gpio_get_ops(dev)->direction_input(dev, offset);
+}
+
+/**
+ * gpio_direction_output() - [COMPAT] Set GPIO direction to output and set value
+ * gpio:	GPIO number
+ * value:	Logical value to be set on the GPIO pin
+ *
+ * This function implements the API that's compatible with current
+ * GPIO API used in U-Boot. The request is forwarded to particular
+ * GPIO driver. Returns 0 on success, negative value on error.
+ */
+int gpio_direction_output(unsigned gpio, int value)
+{
+	unsigned int offset;
+	struct device *dev;
+	int ret;
+
+	ret = gpio_to_device(gpio, &dev, &offset);
+	if (ret)
+		return ret;
+
+	return gpio_get_ops(dev)->direction_output(dev, offset, value);
+}
+
+/**
+ * gpio_get_value() - [COMPAT] Sample GPIO pin and return it's value
+ * gpio:	GPIO number
+ *
+ * This function implements the API that's compatible with current
+ * GPIO API used in U-Boot. The request is forwarded to particular
+ * GPIO driver. Returns the value of the GPIO pin, or negative value
+ * on error.
+ */
+int gpio_get_value(unsigned gpio)
+{
+	unsigned int offset;
+	struct device *dev;
+	int ret;
+
+	ret = gpio_to_device(gpio, &dev, &offset);
+	if (ret)
+		return ret;
+
+	return gpio_get_ops(dev)->get_value(dev, offset);
+}
+
+/**
+ * gpio_set_value() - [COMPAT] Configure logical value on GPIO pin
+ * gpio:	GPIO number
+ * value:	Logical value to be set on the GPIO pin.
+ *
+ * This function implements the API that's compatible with current
+ * GPIO API used in U-Boot. The request is forwarded to particular
+ * GPIO driver. Returns 0 on success, negative value on error.
+ */
+int gpio_set_value(unsigned gpio, int value)
+{
+	unsigned int offset;
+	struct device *dev;
+	int ret;
+
+	ret = gpio_to_device(gpio, &dev, &offset);
+	if (ret)
+		return ret;
+
+	return gpio_get_ops(dev)->set_value(dev, offset, value);
+}
+
+const char *gpio_get_bank_info(struct device *dev, int *bit_count)
+{
+	struct gpio_dev_priv *priv;
+
+	/* Must be called on an active device */
+	priv = dev->uclass_priv;
+	assert(priv);
+
+	*bit_count = priv->gpio_count;
+	return priv->bank_name;
+}
+
+/* We need to renumber the GPIOs when any driver is probed/removed */
+static int gpio_renumber(void)
+{
+	struct gpio_dev_priv *uc_priv;
+	struct device *dev;
+	struct uclass *uc;
+	unsigned base;
+	int ret;
+
+	ret = uclass_get(UCLASS_GPIO, &uc);
+	if (ret)
+		return ret;
+
+	/* Ensure that we have a base for each bank */
+	base = 0;
+	uclass_foreach_dev(dev, uc) {
+		if (device_active(dev)) {
+			uc_priv = dev->uclass_priv;
+			uc_priv->gpio_base = base;
+			base += uc_priv->gpio_count;
+		}
+	}
+
+	return 0;
+}
+
+static int gpio_post_probe(struct device *dev)
+{
+	return gpio_renumber();
+}
+
+static int gpio_pre_remove(struct device *dev)
+{
+	return gpio_renumber();
+}
+
+UCLASS_DRIVER(gpio) = {
+	.id		= UCLASS_GPIO,
+	.name		= "gpio",
+	.post_probe	= gpio_post_probe,
+	.pre_remove	= gpio_pre_remove,
+	.per_device_auto_alloc_size = sizeof(struct gpio_dev_priv),
+};