1/* 2 * linux/arch/sh/kernel/adc.c -- SH3 on-chip ADC support 3 * 4 * Copyright (C) 2004 Andriy Skulysh <askulysh@image.kiev.ua> 5 */ 6 7#include <linux/module.h> 8#include <asm/adc.h> 9#include <asm/io.h> 10 11 12int adc_single(unsigned int channel) 13{ 14 int off; 15 unsigned char csr; 16 17 if (channel >= 8) return -1; 18 19 off = (channel & 0x03) << 2; 20 21 csr = __raw_readb(ADCSR); 22 csr = channel | ADCSR_ADST | ADCSR_CKS; 23 __raw_writeb(csr, ADCSR); 24 25 do { 26 csr = __raw_readb(ADCSR); 27 } while ((csr & ADCSR_ADF) == 0); 28 29 csr &= ~(ADCSR_ADF | ADCSR_ADST); 30 __raw_writeb(csr, ADCSR); 31 32 return (((__raw_readb(ADDRAH + off) << 8) | 33 __raw_readb(ADDRAL + off)) >> 6); 34} 35 36EXPORT_SYMBOL(adc_single); 37