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/*
* RTL819X gpio driver
*
* Copyright 2012 Andrew 'Necromant' Andrianov
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
*
* Please note, that this driver is VERY hacky due to f*cked up nature of
* realtek's kernel. Say thanks to code monkeys from realtek
* (see arch/rlx for emailsand names) and never hire any of them ;)
* This driver should be properly rewritten once 3.x kernels for rlx arrive
* Till then it's a placeholder for a proper driver.
* Current Issues:
* * No interrupt support whatsoever.
* * No proper probing & platform_device defs.
* * Many things hardcoded. Sorry
*
*
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/io.h>
#include <linux/gpio.h>
#include <linux/spinlock.h>
#include <asm/io.h>
/* Register Offset Definitions */
#define RTLGPIO_CNTRL (0)
#define RTLGPIO_DIR (2)
#define RTLGPIO_DATA (3)
/* rlx missing sizes.h ? */
#define SZ_4K 4096
#define RTL_MUX_ADDR 0xb8000040
static int g_muxdummy;
static uint32_t g_mux_value = 0x340FFF;
static int param_set_mux(const char *val, struct kernel_param *kp)
{
volatile uint32_t* mux = (uint32_t*) RTL_MUX_ADDR;
if (!val)
return -EINVAL;
sscanf(val, "0x%x", &g_mux_value);
*mux = g_mux_value;
printk("rtl-gpio: setting mux to 0x%x\n", g_mux_value);
return 0;
}
static int param_get_mux(char *buffer, struct kernel_param *kp)
{
volatile uint32_t* mux = (uint32_t*) RTL_MUX_ADDR;
sprintf(buffer, "0x%x", *mux);
return strlen(buffer);
}
#define param_check_mux(a,b) ;;
module_param_named(mux, g_muxdummy, mux, S_IRUGO | S_IWUSR)
struct rtl_gpio_chip {
struct gpio_chip chip;
uint32_t gpio_state;
uint32_t gpio_dir;
volatile uint32_t* regs;
spinlock_t lock; /* Lock used for synchronization */
};
static inline struct rtl_gpio_chip *to_rtl_gpio_chip(struct gpio_chip *gc)
{
return container_of(gc, struct rtl_gpio_chip, chip);
}
/* Dummy to make gpiolib happy */
int gpio_to_irq(unsigned g)
{
return 0;
}
EXPORT_SYMBOL(gpio_to_irq);
/**
* rtlgpio_get - Read the specified signal of the GPIO device.
* @gc: Pointer to gpio_chip device structure.
* @gpio: GPIO signal number.
*
* This function reads the specified signal of the GPIO device. It returns 0 if
* the signal clear, 1 if signal is set or negative value on error.
*/
static int rtlgpio_get(struct gpio_chip *gc, unsigned int gpio)
{
struct rtl_gpio_chip *rgc = to_rtl_gpio_chip(gc);
return (*(rgc->regs + RTLGPIO_DATA) >> gpio) & 1;
}
/**
* rtlgpio_set - Write the specified signal of the GPIO device.
* @gc: Pointer to gpio_chip device structure.
* @gpio: GPIO signal number.
* @val: Value to be written to specified signal.
*
* This function writes the specified value in to the specified signal of the
* GPIO device.
*/
static void rtlgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
{
unsigned long flags;
struct rtl_gpio_chip *rgc = to_rtl_gpio_chip(gc);
spin_lock_irqsave(&rgc->lock, flags);
/* Write to GPIO signal and set its direction to output */
if (val)
rgc->gpio_state |= 1 << gpio;
else
rgc->gpio_state &= ~(1 << gpio);
*(rgc->regs + RTLGPIO_DATA) = rgc->gpio_state;
spin_unlock_irqrestore(&rgc->lock, flags);
}
/**
* rtlgpio_dir_in - Set the direction of the specified GPIO signal as input.
* @gc: Pointer to gpio_chip device structure.
* @gpio: GPIO signal number.
*
* This function sets the direction of specified GPIO signal as input.
* It returns 0 if direction of GPIO signals is set as input otherwise it
* returns negative error value.
*/
static int rtlgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
{
unsigned long flags;
struct rtl_gpio_chip *rgc = to_rtl_gpio_chip(gc);
spin_lock_irqsave(&rgc->lock, flags);
/* Set the GPIO bit in shadow register and set direction as input */
rgc->gpio_dir &= ~(1 << gpio);
*(rgc->regs + RTLGPIO_DIR) = rgc->gpio_dir;
spin_unlock_irqrestore(&rgc->lock, flags);
return 0;
}
/**
* rtlgpio_dir_out - Set the direction of the specified GPIO signal as output.
* @gc: Pointer to gpio_chip device structure.
* @gpio: GPIO signal number.
* @val: Value to be written to specified signal.
*
* This function sets the direction of specified GPIO signal as output. If all
* GPIO signals of GPIO chip is configured as input then it returns
* error otherwise it returns 0.
*/
static int rtlgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
{
unsigned long flags;
struct rtl_gpio_chip *rgc = to_rtl_gpio_chip(gc);
spin_lock_irqsave(&rgc->lock, flags);
/* Set the GPIO bit in shadow register and set direction as input */
rgc->gpio_dir |= (1 << gpio);
*(rgc->regs + RTLGPIO_DIR) = rgc->gpio_dir;
spin_unlock_irqrestore(&rgc->lock, flags);
return 0;
}
static struct rtl_gpio_chip rgpio;
static int __init rtlgpio_init(void)
{
/* volatile uint32_t* regs = ioremap_nocache(0xb8003500, 32);
volatile uint32_t* mux = ioremap_nocache(0xB8000040, 4);
*/
/*
* Something is definetely not right here.
* Theory says that ioremap is the way, practice says the opposite
* Must be some dark realtek's magic coming from arch/rlx
*/
volatile uint32_t* regs = (uint32_t*) 0xb8003500;
volatile uint32_t* mux = (uint32_t*) 0xb8000040;
*mux = g_mux_value;
printk("rtl-gpio: Hacky Realtek 819x GPIO Driver (c) Andrew 'Necromant' Andrianov 2012\n");
rgpio.chip.direction_input = rtlgpio_dir_in;
rgpio.chip.direction_output = rtlgpio_dir_out;
rgpio.chip.get = rtlgpio_get;
rgpio.chip.label = "rtl-gpio";
rgpio.chip.set = rtlgpio_set;
rgpio.chip.base = 0;
rgpio.chip.ngpio = 32;
spin_lock_init(&rgpio.lock);
rgpio.regs = regs;
rgpio.gpio_state = *(rgpio.regs + RTLGPIO_DATA);
rgpio.gpio_dir = *(rgpio.regs + RTLGPIO_DIR);
printk("rtl-gpio: remaped io regs: 0x%p, mux: 0x%p\n",
regs,
mux);
printk("rtl-gpio: mux:0x%x\n",
*mux);
printk("rtl-gpio: initial dir: 0x%x, value: 0x%x\n",
rgpio.gpio_state,
rgpio.gpio_dir);
gpiochip_add(&rgpio.chip);
return 0;
}
/* Make sure we get initialized before anyone else tries to use us */
subsys_initcall(rtlgpio_init);
/* No exit call at the moment as we cannot unregister of GPIO chips */
MODULE_AUTHOR("Andrew 'Necromant' Andrianov");
MODULE_DESCRIPTION("Hacky RTL819x GPIO Driver");
MODULE_LICENSE("GPL");
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