1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * linux/arch/sh/kernel/adc.c -- SH3 on-chip ADC support 4 * 5 * Copyright (C) 2004 Andriy Skulysh <askulysh@image.kiev.ua> 6 */ 7 8 #include <linux/module.h> 9 #include <asm/adc.h> 10 #include <asm/io.h> 11 12 13 int adc_single(unsigned int channel) 14 { 15 int off; 16 unsigned char csr; 17 18 if (channel >= 8) return -1; 19 20 off = (channel & 0x03) << 2; 21 22 csr = __raw_readb(ADCSR); 23 csr = channel | ADCSR_ADST | ADCSR_CKS; 24 __raw_writeb(csr, ADCSR); 25 26 do { 27 csr = __raw_readb(ADCSR); 28 } while ((csr & ADCSR_ADF) == 0); 29 30 csr &= ~(ADCSR_ADF | ADCSR_ADST); 31 __raw_writeb(csr, ADCSR); 32 33 return (((__raw_readb(ADDRAH + off) << 8) | 34 __raw_readb(ADDRAL + off)) >> 6); 35 } 36 37 EXPORT_SYMBOL(adc_single); 38