xref: /aosp_15_r20/external/coreboot/src/soc/mediatek/common/auxadc.c (revision b9411a12aaaa7e1e6a6fb7c5e057f44ee179a49c)
1 /* SPDX-License-Identifier: GPL-2.0-only */
2 
3 #include <assert.h>
4 #include <delay.h>
5 #include <device/mmio.h>
6 #include <soc/addressmap.h>
7 #include <soc/auxadc.h>
8 #include <soc/efuse.h>
9 #include <timer.h>
10 
11 static struct mtk_auxadc_regs *const mtk_auxadc = (void *)AUXADC_BASE;
12 
13 #define ADC_GE_A_SHIFT		10
14 #define ADC_GE_A_MASK		(0x3ff << ADC_GE_A_SHIFT)
15 #define ADC_OE_A_SHIFT		0
16 #define ADC_OE_A_MASK		(0x3ff << ADC_OE_A_SHIFT)
17 #define ADC_CALI_EN_A_SHIFT	20
18 #define ADC_CALI_EN_A_MASK	(0x1 << ADC_CALI_EN_A_SHIFT)
19 
20 static int cali_oe;
21 static int cali_ge;
22 static int calibrated = 0;
mt_auxadc_update_cali(void)23 static void mt_auxadc_update_cali(void)
24 {
25 	uint32_t cali_reg;
26 	int cali_ge_a;
27 	int cali_oe_a;
28 
29 	cali_reg = read32(&mtk_efuse->adc_cali_reg);
30 
31 	if ((cali_reg & ADC_CALI_EN_A_MASK) != 0) {
32 		cali_oe_a = (cali_reg & ADC_OE_A_MASK) >> ADC_OE_A_SHIFT;
33 		cali_ge_a = (cali_reg & ADC_GE_A_MASK) >> ADC_GE_A_SHIFT;
34 		cali_ge = cali_ge_a - 512;
35 		cali_oe = cali_oe_a - 512;
36 	}
37 }
38 
auxadc_get_rawdata(int channel)39 static uint32_t auxadc_get_rawdata(int channel)
40 {
41 	setbits32(&mtk_infracfg->module_sw_cg_1_clr, 1 << 10);
42 	assert(wait_ms(300, !(read32(&mtk_auxadc->con2) & 0x1)));
43 
44 	clrbits32(&mtk_auxadc->con1, 1 << channel);
45 	assert(wait_ms(300, !(read32(&mtk_auxadc->data[channel]) & (1 << 12))));
46 
47 	setbits32(&mtk_auxadc->con1, 1 << channel);
48 	udelay(25);
49 	assert(wait_ms(300, read32(&mtk_auxadc->data[channel]) & (1 << 12)));
50 
51 	uint32_t value = read32(&mtk_auxadc->data[channel]) & 0x0FFF;
52 
53 	setbits32(&mtk_infracfg->module_sw_cg_1_set, 1 << 10);
54 
55 	return value;
56 }
57 
auxadc_get_voltage_uv(unsigned int channel)58 unsigned int auxadc_get_voltage_uv(unsigned int channel)
59 {
60 	uint32_t raw_value;
61 	assert(channel < 16);
62 
63 	if (!calibrated) {
64 		mt_auxadc_update_cali();
65 		calibrated = 1;
66 	}
67 
68 	/* 1.5V in 4096 steps */
69 	raw_value = auxadc_get_rawdata(channel);
70 	raw_value = raw_value - cali_oe;
71 	return (unsigned int)((int64_t)raw_value * 1500000 / (4096 + cali_ge));
72 }
73