/*
 * gpio_devmem.h — Direct GPIO control via /dev/mem for KL630
 *
 * Purpose:
 *   Bypass kernel driver pinmux conflicts by directly accessing GPIO registers
 *   in physical memory. Used when J15 GPIO pins are already claimed by another
 *   kernel module (e.g., dh2228fv display driver).
 *
 * Register Layout (KL630, GPIO_C base = 0x402E0000):
 *   +0x0000: GPIOD_PSR     — Port Status Register (read-only, shows pin states)
 *   +0x0004: GPIOD_PDDR    — Port Data Direction Register (0=input, 1=output)
 *   +0x0008: GPIOD_PSOR    — Port Set Output Register (write 1 to set pin=1)
 *   +0x000C: GPIOD_PCOR    — Port Clear Output Register (write 1 to set pin=0)
 *   +0x0010: GPIOD_PTOR    — Port Toggle Output Register
 *   +0x0014: GPIOD_PIDR    — Port Input Disable Register
 *
 * Usage:
 *   gpio_devmem_init();
 *   gpio_devmem_set(1, 1);    // GPIO1 = high
 *   gpio_devmem_get(4);       // read GPIO4
 *   gpio_devmem_cleanup();
 *
 * Note: must run as root (CAP_SYS_RAWIO for /dev/mem access).
 */

#ifndef GPIO_DEVMEM_H
#define GPIO_DEVMEM_H

#include <stdint.h>

/*
 * Initialize GPIO via /dev/mem.
 * Returns: 0 on success, -1 on error.
 */
int gpio_devmem_init(void);

/*
 * Cleanup /dev/mem mapping.
 */
void gpio_devmem_cleanup(void);

/*
 * Set GPIO pin direction.
 * gpio: 1-4 (J15 pins)
 * output: 1 = output, 0 = input
 * Returns: 0 on success, -1 on error.
 */
int gpio_devmem_set_direction(int gpio, int output);

/*
 * Set GPIO pin: 1 = high, 0 = low.
 * gpio: 1-4 (J15 pins)
 * value: 0 or 1
 * Returns: 0 on success, -1 on error.
 */
int gpio_devmem_set(int gpio, int value);

/*
 * Get GPIO pin state: 0 = low, 1 = high.
 * gpio: 1-4 (J15 pins)
 * Returns: 0, 1, or -1 on error.
 */
int gpio_devmem_get(int gpio);

#endif /* GPIO_DEVMEM_H */