adc.c

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/*
 * linux/arch/sh/kernel/adc.c -- SH3 on-chip ADC support
 *
 *  Copyright (C) 2004  Andriy Skulysh <[email protected]>
 */

#include <linux/module.h>
#include <asm/adc.h>
#include <asm/io.h>


int adc_single(unsigned int channel)
{
    int off;
    unsigned char csr;

    if (channel >= 8) return -1;

    off = (channel & 0x03) << 2;

    csr = __raw_readb(ADCSR);
    csr = channel | ADCSR_ADST | ADCSR_CKS;
    __raw_writeb(csr, ADCSR);

    do {
        csr = __raw_readb(ADCSR);
    } while ((csr & ADCSR_ADF) == 0);

    csr &= ~(ADCSR_ADF | ADCSR_ADST);
    __raw_writeb(csr, ADCSR);

    return (((__raw_readb(ADDRAH + off) << 8) |
        __raw_readb(ADDRAL + off)) >> 6);
}

EXPORT_SYMBOL(adc_single);