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
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