157 lines
4.3 KiB
C
157 lines
4.3 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/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 BH1730_DEFAULT_GAIN BH1730_GAIN_64X
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#define BH1730_DEFAULT_ICYCLE 38
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#define BH1730_INTERNAL_CLOCK_NS 2800
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#define BH1730_ADC_CALC_DELAY_US 2000 /* BH1730_INTERNAL_CLOCK_MS * 714 */
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#define BH1730_ITIME_CYCLE_TO_US 2700 /* BH1730_INTERNAL_CLOCK_MS * 964 */
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#define BH1730_DEFAULT_ITIME_MS 100
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#define BH1730_LUX_MULTIPLIER 3600
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#define BH1730_LUX_MULTIPLIER_AULA 1410
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#define BH1730_LUX_MAX 100000
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typedef struct _opt_win_cal_t
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{
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u32 rc;
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u32 cv;
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u32 ci;
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} opt_win_cal_t;
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// Nintendo Switch Icosa/Iowa Optical Window calibration.
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const opt_win_cal_t opt_win_cal_default[] = {
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{ 500, 5002, 7502 },
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{ 754, 2250, 2000 },
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{ 1029, 1999, 1667 },
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{ 1373, 884, 583 },
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{ 1879, 309, 165 }
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};
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// Nintendo Switch Aula Optical Window calibration.
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const opt_win_cal_t opt_win_cal_aula[] = {
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{ 231, 9697, 30300 },
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{ 993, 3333, 2778 },
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{ 1478, 1621, 1053 },
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{ 7500, 81, 10 }
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};
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const u32 als_gain_idx_tbl[4] = { 1, 2, 64, 128 };
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void set_als_cfg(als_ctxt_t *als_ctxt, u8 gain, u8 cycle)
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{
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if (gain > BH1730_GAIN_128X)
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gain = BH1730_GAIN_128X;
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if (!cycle)
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cycle = 1;
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else if (cycle > 255)
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cycle = 255;
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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 - cycle));
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als_ctxt->gain = gain;
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als_ctxt->cycle = cycle;
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}
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void get_als_lux(als_ctxt_t *als_ctxt)
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{
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u32 data[2];
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u32 visible_light;
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u32 ir_light;
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u64 lux = 0;
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u32 itime_us = BH1730_ITIME_CYCLE_TO_US * als_ctxt->cycle;
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// Get visible and ir light raw data. Mode is continuous so waiting for new values doesn't matter.
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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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visible_light = data[0];
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ir_light = data[1];
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als_ctxt->over_limit = visible_light > 65534 || ir_light > 65534;
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als_ctxt->vi_light = visible_light;
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als_ctxt->ir_light = ir_light;
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if (!visible_light)
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{
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als_ctxt->lux = 0;
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return;
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}
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// Set calibration parameters.
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u32 lux_multiplier = BH1730_LUX_MULTIPLIER;
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u32 opt_win_cal_count = ARRAY_SIZE(opt_win_cal_default);
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const opt_win_cal_t *opt_win_cal = opt_win_cal_default;
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// Apply optical window calibration coefficients.
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for (u32 i = 0; i < opt_win_cal_count; i++)
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{
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if (1000 * ir_light / visible_light < opt_win_cal[i].rc)
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{
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lux = ((u64)opt_win_cal[i].cv * data[0]) - (opt_win_cal[i].ci * data[1]);
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break;
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}
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}
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lux *= BH1730_DEFAULT_ITIME_MS * lux_multiplier;
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lux /= als_gain_idx_tbl[als_ctxt->gain] * itime_us;
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lux /= 1000;
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if (lux > BH1730_LUX_MAX)
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lux = BH1730_LUX_MAX;
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als_ctxt->lux = lux;
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}
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u8 als_power_on(als_ctxt_t *als_ctxt)
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{
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// Enable power to ALS IC.
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max7762x_regulator_set_voltage(REGULATOR_LDO6, 2900000);
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max7762x_regulator_enable(REGULATOR_LDO6, true);
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// Init I2C2.
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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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// Initialize ALS.
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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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set_als_cfg(als_ctxt, BH1730_DEFAULT_GAIN, BH1730_DEFAULT_ICYCLE);
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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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return id;
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}
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