/*
* "AT91 ADC" kernel module
*
* Evgeny Startsev <slayer-gurgen@yandex.ru>
*
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/delay.h>
#include <mach/at91_adc.h>
#include <linux/platform_device.h>
#include <asm/io.h>
#include <mach/gpio.h>

#define ADC_BASE 0xFFFE0000
struct resource *res;
void __iomem *addr;

static int __init
hello_init(void)
{
printk("Hello, world!\n");
res = request_mem_region(ADC_BASE, 0xffff, "Mymem");
addr = ioremap(res->start, 0xffff);
at91_set_B_periph(AT91_PIN_PC0, 0);
__raw_writel(AT91_ADC_SWRST, addr + AT91_ADC_CR);
__raw_writel(AT91_ADC_LOWRES|
AT91_ADC_PRESCAL_(15)|
AT91_ADC_STARTUP_(0)|
AT91_ADC_SHTIM_(2000),
addr + AT91_ADC_MR);
char str[16];

/*Debug*/
sprintf(str, "Before %d\n", __raw_readl(addr+AT91_ADC_CHSR));
printk(str);

__raw_writel(1, addr + AT91_ADC_CHER);
__raw_writel(0xFFFF, addr + AT91_ADC_IDR);//no irq

/*Debug*/
sprintf(str, "After %d\n", __raw_readl(addr+AT91_ADC_CHSR));
printk(str);

__raw_writel(AT91_ADC_START, addr + AT91_ADC_CR);
while(!(__raw_readl(addr+AT91_ADC_SR) & 1)){
}
sprintf(str, "%d", __raw_readl(addr+AT91_ADC_LCDR));
printk(str);
return 0;
}


module_init(hello_init);


static void __exit
hello_exit(void)
{
printk("Goodbye, world!\n");
release_mem_region(ADC_BASE, 0xffff);
at91_set_GPIO_periph(AT91_PIN_PC0, 0);
}

module_exit(hello_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Evgeny Startsev <slayer-gurgen@yandex.ru>");
MODULE_DESCRIPTION("ADC module");
MODULE_VERSION("1");

...
at91adc_clk = clk_get(NULL, // Device pointer - not required.
"adc_clk"); // Clock name.
clk_enable(at91adc_clk);
...