120 lines
3.9 KiB
C
120 lines
3.9 KiB
C
/*
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* Ambient light sensor driver for Nintendo Switch's Rohm BH1730
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*
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* Copyright (c) 2018 CTCaer
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "als.h"
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#include <power/max77620.h>
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#include <power/max7762x.h>
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#include <soc/clock.h>
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#include <soc/i2c.h>
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#include <soc/pinmux.h>
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#include <utils/util.h>
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#define HOS_GAIN BH1730_GAIN_64X
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#define HOS_ITIME 38
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void set_als_cfg(als_table_t *als_val, u8 gain, u8 itime)
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{
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i2c_send_byte(I2C_2, BH1730_I2C_ADDR, BH1730_ADDR(BH1730_GAIN_REG), gain);
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i2c_send_byte(I2C_2, BH1730_I2C_ADDR, BH1730_ADDR(BH1730_TIMING_REG), (256 - itime));
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als_val->gain = gain;
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als_val->itime = itime;
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}
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void get_als_lux(als_table_t *als_val)
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{
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u32 data[2];
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float pre_gain_lux;
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float visible_light;
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float ir_light;
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float light_ratio;
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u8 adc_ready = 0;
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u8 retries = 100;
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const float als_gain_idx_tbl[4] = { 1.0, 2.0, 64.0, 128.0 };
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const float als_norm_res = 100.0;
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const float als_multiplier = 3.6;
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const float als_tint = 2.7;
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// Wait for ADC to prepare new data.
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while (!(adc_ready & BH1730_CTL_ADC_VALID) && retries)
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{
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retries--;
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adc_ready = i2c_recv_byte(I2C_2, BH1730_I2C_ADDR, BH1730_ADDR(BH1730_CONTROL_REG));
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}
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// Get visible and ir light raw data.
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data[0] = i2c_recv_byte(I2C_2, BH1730_I2C_ADDR, BH1730_ADDR(BH1730_DATA0LOW_REG)) +
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(i2c_recv_byte(I2C_2, BH1730_I2C_ADDR, BH1730_ADDR(BH1730_DATA0HIGH_REG)) << 8);
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data[1] = i2c_recv_byte(I2C_2, BH1730_I2C_ADDR, BH1730_ADDR(BH1730_DATA1LOW_REG)) +
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(i2c_recv_byte(I2C_2, BH1730_I2C_ADDR, BH1730_ADDR(BH1730_DATA1HIGH_REG)) << 8);
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als_val->over_limit = data[0] > 65534 || data[1] > 65534;
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als_val->vi_light = data[0];
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als_val->ir_light = data[1];
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if (!data[0] || !retries)
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{
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als_val->lux = 0.0;
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return;
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}
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visible_light = (float)data[0];
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ir_light = (float)data[1];
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light_ratio = (float)data[1] / (float)data[0];
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// The following are specific to the light filter Switch uses.
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if (light_ratio < 0.5)
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pre_gain_lux = visible_light * 5.002 - ir_light * 7.502;
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else if (light_ratio < 0.754)
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pre_gain_lux = visible_light * 2.250 - ir_light * 2.000;
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else if (light_ratio < 1.029)
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pre_gain_lux = visible_light * 1.999 - ir_light * 1.667;
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else if (light_ratio < 1.373)
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pre_gain_lux = visible_light * 0.884 - ir_light * 0.583;
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else if (light_ratio < 1.879)
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pre_gain_lux = visible_light * 0.309 - ir_light * 0.165;
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else pre_gain_lux = 0.0;
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als_val->lux = (pre_gain_lux / als_gain_idx_tbl[als_val->gain]) * (als_norm_res / ((float)als_val->itime * als_tint)) * als_multiplier;
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}
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u8 als_init(als_table_t *als_val)
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{
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pinmux_config_i2c(I2C_2);
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clock_enable_i2c(I2C_2);
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i2c_init(I2C_2);
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max77620_regulator_set_volt_and_flags(REGULATOR_LDO6, 2900000, MAX77620_POWER_MODE_NORMAL);
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i2c_send_byte(I2C_5, MAX77620_I2C_ADDR, MAX77620_REG_LDO6_CFG2,
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(MAX77620_POWER_MODE_NORMAL << MAX77620_LDO_POWER_MODE_SHIFT | (3 << 3) | MAX77620_LDO_CFG2_ADE_ENABLE));
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u8 id = i2c_recv_byte(I2C_2, BH1730_I2C_ADDR, BH1730_ADDR(0x12));
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i2c_send_byte(I2C_2, BH1730_I2C_ADDR, BH1730_SPEC(BH1730_SPECCMD_RESET), 0);
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i2c_send_byte(I2C_2, BH1730_I2C_ADDR, BH1730_ADDR(BH1730_GAIN_REG), HOS_GAIN);
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i2c_send_byte(I2C_2, BH1730_I2C_ADDR, BH1730_ADDR(BH1730_TIMING_REG), (256 - HOS_ITIME));
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i2c_send_byte(I2C_2, BH1730_I2C_ADDR, BH1730_ADDR(BH1730_CONTROL_REG), BH1730_CTL_POWER_ON | BH1730_CTL_ADC_EN);
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als_val->gain = HOS_GAIN;
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als_val->itime = HOS_ITIME;
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return id;
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}
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