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@@ -0,0 +1,99 @@
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+/*
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+ * SPDX-License-Identifier: BSD-2-Clause
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+ *
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+ * Copyright (c) 2021 Western Digital Corporation or its affiliates.
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+ *
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+ * Authors:
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+ * Anup Patel <anup.patel@wdc.com>
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+ */
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+
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+#ifndef __GPIO_H__
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+#define __GPIO_H__
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+
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+#include <sbi/sbi_types.h>
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+
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+#define GPIO_LINE_DIRECTION_IN 1
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+#define GPIO_LINE_DIRECTION_OUT 0
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+
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+/** Representation of a GPIO pin */
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+struct gpio_pin {
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+ /** Pointer to the GPIO chip */
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+ struct gpio_chip *chip;
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+ /** Identification of GPIO pin within GPIO chip */
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+ unsigned int offset;
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+ /**
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+ * Additional configuration flags of the GPIO pin desired
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+ * by GPIO clients.
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+ *
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+ * NOTE: GPIO chip can have custom configuration flags.
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+ */
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+ unsigned int flags;
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+#define GPIO_FLAG_ACTIVE_LOW 0x1
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+#define GPIO_FLAG_SINGLE_ENDED 0x2
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+#define GPIO_FLAG_OPEN_DRAIN 0x4
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+#define GPIO_FLAG_TRANSITORY 0x8
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+#define GPIO_FLAG_PULL_UP 0x10
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+#define GPIO_FLAG_PULL_DOWN 0x20
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+};
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+
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+/** Representation of a GPIO chip */
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+struct gpio_chip {
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+ /** Pointer to GPIO driver owning this GPIO chip */
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+ void *driver;
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+ /** Uniquie ID of the GPIO chip assigned by the driver */
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+ unsigned int id;
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+ /** Number of GPIOs supported by the GPIO chip */
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+ unsigned int ngpio;
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+ /**
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+ * Get current direction of GPIO pin
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+ *
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+ * @return 0=output, 1=input, or negative error
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+ */
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+ int (*get_direction)(struct gpio_pin *gp);
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+ /**
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+ * Set input direction of GPIO pin
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+ *
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+ * @return 0 on success and negative error code on failure
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+ */
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+ int (*direction_input)(struct gpio_pin *gp);
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+ /**
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+ * Set output direction of GPIO pin with given output value
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+ *
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+ * @return 0 on success and negative error code on failure
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+ */
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+ int (*direction_output)(struct gpio_pin *gp, int value);
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+ /**
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+ * Get current value of GPIO pin
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+ *
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+ * @return 0=low, 1=high, or negative error
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+ */
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+ int (*get)(struct gpio_pin *gp);
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+ /** Set output value for GPIO pin */
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+ void (*set)(struct gpio_pin *gp, int value);
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+};
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+
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+/** Find a registered GPIO chip */
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+struct gpio_chip *gpio_chip_find(unsigned int id);
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+
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+/** Register GPIO chip */
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+int gpio_chip_add(struct gpio_chip *gc);
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+
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+/** Un-register GPIO chip */
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+void gpio_chip_remove(struct gpio_chip *gc);
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+
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+/** Get current direction of GPIO pin */
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+int gpio_get_direction(struct gpio_pin *gp);
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+
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+/** Set input direction of GPIO pin */
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+int gpio_direction_input(struct gpio_pin *gp);
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+
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+/** Set output direction of GPIO pin */
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+int gpio_direction_output(struct gpio_pin *gp, int value);
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+
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+/** Get current value of GPIO pin */
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+int gpio_get(struct gpio_pin *gp);
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+
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+/** Set output value of GPIO pin */
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+int gpio_set(struct gpio_pin *gp, int value);
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+
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+#endif
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