auxadc.c

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/* SPDX-License-Identifier: GPL-2.0-only */
 
#include <assert.h>
#include <delay.h>
#include <device/mmio.h>
#include <soc/addressmap.h>
#include <soc/auxadc.h>
#include <soc/efuse.h>
#include <timer.h>
 
static struct mtk_auxadc_regs *const mtk_auxadc = (void *)AUXADC_BASE;
 
#define ADC_GE_A_SHIFT          10
#define ADC_GE_A_MASK           (0x3ff << ADC_GE_A_SHIFT)
#define ADC_OE_A_SHIFT          0
#define ADC_OE_A_MASK           (0x3ff << ADC_OE_A_SHIFT)
#define ADC_CALI_EN_A_SHIFT     20
#define ADC_CALI_EN_A_MASK      (0x1 << ADC_CALI_EN_A_SHIFT)
 
static int cali_oe;
static int cali_ge;
static int calibrated = 0;
static void mt_auxadc_update_cali(void)
{
        uint32_t cali_reg;
        int cali_ge_a;
        int cali_oe_a;
 
        cali_reg = read32(&mtk_efuse->adc_cali_reg);
 
        if ((cali_reg & ADC_CALI_EN_A_MASK) != 0) {
                cali_oe_a = (cali_reg & ADC_OE_A_MASK) >> ADC_OE_A_SHIFT;
                cali_ge_a = (cali_reg & ADC_GE_A_MASK) >> ADC_GE_A_SHIFT;
                cali_ge = cali_ge_a - 512;
                cali_oe = cali_oe_a - 512;
        }
}
 
static uint32_t auxadc_get_rawdata(int channel)
{
        setbits32(&mtk_infracfg->module_sw_cg_1_clr, 1 << 10);
        assert(wait_ms(300, !(read32(&mtk_auxadc->con2) & 0x1)));
 
        clrbits32(&mtk_auxadc->con1, 1 << channel);
        assert(wait_ms(300, !(read32(&mtk_auxadc->data[channel]) & (1 << 12))));
 
        setbits32(&mtk_auxadc->con1, 1 << channel);
        udelay(25);
        assert(wait_ms(300, read32(&mtk_auxadc->data[channel]) & (1 << 12)));
 
        uint32_t value = read32(&mtk_auxadc->data[channel]) & 0x0FFF;
 
        setbits32(&mtk_infracfg->module_sw_cg_1_set, 1 << 10);
 
        return value;
}
 
unsigned int auxadc_get_voltage_uv(unsigned int channel)
{
        uint32_t raw_value;
        assert(channel < 16);
 
        if (!calibrated) {
                mt_auxadc_update_cali();
                calibrated = 1;
        }
 
        /* 1.5V in 4096 steps */
        raw_value = auxadc_get_rawdata(channel);
        raw_value = raw_value - cali_oe;
        return (unsigned int)((int64_t)raw_value * 1500000 / (4096 + cali_ge));
}