--- /dev/null
+/*
+ * 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
--- /dev/null
+/*
+ * 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;
+}