3 files changed, 225 insertions, 0 deletions
diff --git a/include/sbi_utils/gpio/gpio.h b/include/sbi_utils/gpio/gpio.h
new file mode 100644
index 0000000..167d11a
--- /dev/null
+++ b/include/sbi_utils/gpio/gpio.h
@@ -0,0 +1,99 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2021 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *   Anup Patel <anup.patel@wdc.com>
+ */
+
+#ifndef __GPIO_H__
+#define __GPIO_H__
+
+#include <sbi/sbi_types.h>
+
+#define GPIO_LINE_DIRECTION_IN	1
+#define GPIO_LINE_DIRECTION_OUT	0
+
+/** Representation of a GPIO pin */
+struct gpio_pin {
+	/** Pointer to the GPIO chip */
+	struct gpio_chip *chip;
+	/** Identification of GPIO pin within GPIO chip */
+	unsigned int offset;
+	/**
+	 * Additional configuration flags of the GPIO pin desired
+	 * by GPIO clients.
+	 *
+	 * NOTE: GPIO chip can have custom configuration flags.
+	 */
+	unsigned int flags;
+#define GPIO_FLAG_ACTIVE_LOW	0x1
+#define GPIO_FLAG_SINGLE_ENDED	0x2
+#define GPIO_FLAG_OPEN_DRAIN	0x4
+#define GPIO_FLAG_TRANSITORY	0x8
+#define GPIO_FLAG_PULL_UP	0x10
+#define GPIO_FLAG_PULL_DOWN	0x20
+};
+
+/** Representation of a GPIO chip */
+struct gpio_chip {
+	/** Pointer to GPIO driver owning this GPIO chip */
+	void *driver;
+	/** Uniquie ID of the GPIO chip assigned by the driver */
+	unsigned int id;
+	/** Number of GPIOs supported by the GPIO chip */
+	unsigned int ngpio;
+	/**
+	 * Get current direction of GPIO pin
+	 *
+	 * @return 0=output, 1=input, or negative error
+	 */
+	int (*get_direction)(struct gpio_pin *gp);
+	/**
+	 * Set input direction of GPIO pin
+	 *
+	 * @return 0 on success and negative error code on failure
+	 */
+	int (*direction_input)(struct gpio_pin *gp);
+	/**
+	 * Set output direction of GPIO pin with given output value
+	 *
+	 * @return 0 on success and negative error code on failure
+	 */
+	int (*direction_output)(struct gpio_pin *gp, int value);
+	/**
+	 * Get current value of GPIO pin
+	 *
+	 * @return 0=low, 1=high, or negative error
+	 */
+	int (*get)(struct gpio_pin *gp);
+	/** Set output value for GPIO pin */
+	void (*set)(struct gpio_pin *gp, int value);
+};
+
+/** Find a registered GPIO chip */
+struct gpio_chip *gpio_chip_find(unsigned int id);
+
+/** Register GPIO chip */
+int gpio_chip_add(struct gpio_chip *gc);
+
+/** Un-register GPIO chip */
+void gpio_chip_remove(struct gpio_chip *gc);
+
+/** Get current direction of GPIO pin */
+int gpio_get_direction(struct gpio_pin *gp);
+
+/** Set input direction of GPIO pin */
+int gpio_direction_input(struct gpio_pin *gp);
+
+/** Set output direction of GPIO pin */
+int gpio_direction_output(struct gpio_pin *gp, int value);
+
+/** Get current value of GPIO pin */
+int gpio_get(struct gpio_pin *gp);
+
+/** Set output value of GPIO pin */
+int gpio_set(struct gpio_pin *gp, int value);
+
+#endif
diff --git a/lib/utils/gpio/gpio.c b/lib/utils/gpio/gpio.c
new file mode 100644
index 0000000..fb30c0f
--- /dev/null
+++ b/lib/utils/gpio/gpio.c
@@ -0,0 +1,116 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2021 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *   Anup Patel <anup.patel@wdc.com>
+ */
+
+#include <sbi/sbi_error.h>
+#include <sbi_utils/gpio/gpio.h>
+
+#define GPIO_CHIP_MAX		16
+
+static struct gpio_chip *gc_array[GPIO_CHIP_MAX];
+
+struct gpio_chip *gpio_chip_find(unsigned int id)
+{
+	unsigned int i;
+	struct gpio_chip *ret = NULL;
+
+	for (i = 0; i < GPIO_CHIP_MAX; i++) {
+		if (gc_array[i] && gc_array[i]->id == id) {
+			ret = gc_array[i];
+			break;
+		}
+	}
+
+	return ret;
+}
+
+int gpio_chip_add(struct gpio_chip *gc)
+{
+	int i, ret = SBI_ENOSPC;
+
+	if (!gc)
+		return SBI_EINVAL;
+	if (gpio_chip_find(gc->id))
+		return SBI_EALREADY;
+
+	for (i = 0; i < GPIO_CHIP_MAX; i++) {
+		if (!gc_array[i]) {
+			gc_array[i] = gc;
+			ret = 0;
+			break;
+		}
+	}
+
+	return ret;
+}
+
+void gpio_chip_remove(struct gpio_chip *gc)
+{
+	int i;
+
+	if (!gc)
+		return;
+
+	for (i = 0; i < GPIO_CHIP_MAX; i++) {
+		if (gc_array[i] == gc) {
+			gc_array[i] = NULL;
+			break;
+		}
+	}
+}
+
+int gpio_get_direction(struct gpio_pin *gp)
+{
+	if (!gp || !gp->chip || (gp->chip->ngpio <= gp->offset))
+		return SBI_EINVAL;
+	if (!gp->chip->get_direction)
+		return SBI_ENOSYS;
+
+	return gp->chip->get_direction(gp);
+}
+
+int gpio_direction_input(struct gpio_pin *gp)
+{
+	if (!gp || !gp->chip || (gp->chip->ngpio <= gp->offset))
+		return SBI_EINVAL;
+	if (!gp->chip->direction_input)
+		return SBI_ENOSYS;
+
+	return gp->chip->direction_input(gp);
+}
+
+int gpio_direction_output(struct gpio_pin *gp, int value)
+{
+	if (!gp || !gp->chip || (gp->chip->ngpio <= gp->offset))
+		return SBI_EINVAL;
+	if (!gp->chip->direction_output)
+		return SBI_ENOSYS;
+
+	return gp->chip->direction_output(gp, value);
+}
+
+int gpio_get(struct gpio_pin *gp)
+{
+	if (!gp || !gp->chip || (gp->chip->ngpio <= gp->offset))
+		return SBI_EINVAL;
+	if (!gp->chip->get)
+		return SBI_ENOSYS;
+
+	return gp->chip->get(gp);
+}
+
+int gpio_set(struct gpio_pin *gp, int value)
+{
+	if (!gp || !gp->chip || (gp->chip->ngpio <= gp->offset))
+		return SBI_EINVAL;
+	if (!gp->chip->set)
+		return SBI_ENOSYS;
+
+	gp->chip->set(gp, value);
+	return 0;
+}
diff --git a/lib/utils/gpio/objects.mk b/lib/utils/gpio/objects.mk
new file mode 100644
index 0000000..e99a895
--- /dev/null
+++ b/lib/utils/gpio/objects.mk
@@ -0,0 +1,10 @@
+#
+# SPDX-License-Identifier: BSD-2-Clause
+#
+# Copyright (c) 2021 Western Digital Corporation or its affiliates.
+#
+# Authors:
+#   Anup Patel <anup.patel@wdc.com>
+#
+
+libsbiutils-objs-y += gpio/gpio.o