/*
  direct GPIO access code for net5501 running linux
  Matthew Kaufman 3/24/2009, 4/1/2009
  Direct driverless access to PC87366 for GPIO and CS5536 for Error LED

  For register details see pgs 480 onward of:
    http://www.amd.com/files/connectivitysolutions/geode/geode_lx/33238G_cs5536_db.pdf
  And page 129 onward of:
    http://www.datasheetcatalog.org/datasheet/nationalsemiconductor/PC87366.pdf

  This is example code. A fancier version would make it easier to work with more than one
  pin at a time.
*/
  
#include <stdio.h>
#include <sys/io.h>

#define GPIO_BASE_CS5535   0x6100      /* rather than asking MSR_LBAR_GPIO which is harder to do */

#define SIO_INDEX            0x2e      /* index register of PC87366 Super I/O */
#define SIO_DATA             0x2f      /* data register of PC87366 Super I/O */

#define SIO_REG_SID          0x20      /* Configuration register containing ID */
#define SIO_SID_VALUE        0xe9      /* Expected ID value */

#define SIO_REG_LDN          0x07      /* Configuration register: logical device number selector */

#define SIO_LDN_GPIO         0x07      /* LDN Value to select GPIO configuration */

#define SIO_REG_ACTIVATE     0x30      /* (Shared) Device register: Activate */

#define SIO_REG_BASE_MSB_0   0x60      /* (Shared) Device register: I/O Port base, descriptor 0, MSB */
#define SIO_REG_BASE_LSB_0   0x61      /* (Shared) Device register: I/O Port base, descriptor 0, LSB */

#define SIO_GPIO_PIN_SELECT  0xf0      /* GPIO device-specific register: Pin select */
#define SIO_GPIO_PIN_CONFIG  0xf1      /* GPIO device-specific register: Pin configuration */

int gpio_base = 0;

int pin_init()
{
	int i;

	if(iopl(3))	/* allow direct I/O access at 0x2e, 0x6100, 0x6640 and thereabouts. must be root. */
		return -1;

	outb(SIO_REG_SID, SIO_INDEX);	/* probe PC87366 */
	i = inb(SIO_DATA);
	if(i != SIO_SID_VALUE)
		return -1;

	outb(SIO_REG_BASE_MSB_0, SIO_INDEX);	/* get MSB of GPIO I/O */
	gpio_base = inb(SIO_DATA) << 8;
	outb(SIO_REG_BASE_LSB_0, SIO_INDEX);	/* get LSB of GPIO I/O */
	gpio_base |= inb(SIO_DATA);

	/* turn on GPIO */

	/* Note: the pin configuration calls assume that this logical device select hasn't been overridden */
	/* if that's a problem in practice, the next two lines must be added to the _pin_config function   */

	outb(SIO_REG_LDN, SIO_INDEX);     /* logical device select */
	outb(SIO_LDN_GPIO, SIO_DATA);     /* select GPIO */


	outb(SIO_REG_ACTIVATE, SIO_INDEX); /* activation for selected device, which is GPIO */
	outb(0x01, SIO_DATA);              /* active */

	return 0;

}

void error_led_set()
{
	/* error LED is GPIO 6 on the CS5535 */

	outl(1 << 6, GPIO_BASE_CS5535); /* using CS5535 atomic set */
}

void error_led_clear()
{
	outl(1 << (6+16), GPIO_BASE_CS5535); /* using CS5535 atomic clear */
}

static int _pin_to_gpio(int pin)
{
	/* mapping table from email by Ralph Becker-Szendy */

	switch(pin)
	{
	case 3: return 16;
	case 4: return 17;
	case 5: return 18;
	case 6: return 19;
	case 7: return 20;
	case 8: return 21;
	case 9: return 22;
	case 10: return 23;
	case 12: return 4;
	case 13: return 5;
	case 15: return 11;
	case 16: return 10;
	default: return -1;
	}
}

int pin_test(int pin)
{
	int gpio = _pin_to_gpio(pin);
	int offset;
	int i;

	if(gpio < 0)
		return;
	if(gpio >= 16)
		offset = 0x09;
	else if(gpio >= 8)
		offset = 0x05;
	else
		offset = 0x01;

	i = inb(gpio_base + offset);
	return(i & (1 << (gpio & 0x07)));
}
	
void pin_set_to(int pin, int set)
{
	int gpio = _pin_to_gpio(pin);
	int offset;
	int i;

	if(gpio_base == 0)
		return;	/* not initialized */

	if(gpio < 0)
		return;

	if(gpio >= 16)
		offset = 0x08;
	else if(gpio >= 8)
		offset = 0x04;
	else
		offset = 0x00;

	i = inb(gpio_base + offset);
	if(set)
	{
		i |= 1 << (gpio & 0x07);
	}
	else
	{
		i &= ~(1 << (gpio & 0x07));
	}
	outb(i, gpio_base + offset);
}

void pin_set(int pin)
{
	pin_set_to(pin, 1);
}

void pin_clear(int pin)
{
	pin_set_to(pin, 0);
}

static void _pin_config(int pin, int bit, int set)
{
	int gpio = _pin_to_gpio(pin);
	int i;

	if(gpio_base == 0)
		return;	/* not initialized */

	if(gpio < 0)
		return;

	/* See note above about how we assume GPIO logical device is already selected */

	outb(SIO_GPIO_PIN_SELECT, SIO_INDEX);
	outb(((gpio & 0x38) << 1) | (gpio & 0x07), SIO_DATA);

	outb( SIO_GPIO_PIN_CONFIG, SIO_INDEX);
	i = inb(SIO_DATA);

	if(set)
	{
		i |= 1 << bit;
	}
	else
	{
		i &= ~(1 << bit);
	}

	outb( i, SIO_DATA);
}

void pin_output_enable(int pin)
{
	_pin_config(pin, 0, 1);
}

void pin_output_disable(int pin)
{
	_pin_config(pin, 0, 0);
}

void pin_output_pushpull(int pin)
{
	_pin_config(pin, 1, 1);
}

void pin_output_opendrain(int pin)
{
	_pin_config(pin, 1, 0);
}

void pin_output_pullup_enable(int pin)
{
	_pin_config(pin, 2, 1);
}

void pin_output_pullup_disable(int pin)
{
	_pin_config(pin, 2, 0);
}