From e65a7e3075a7a153ea478d4fd293ae65b31e33ed Mon Sep 17 00:00:00 2001
From: Xudong Zheng <7pkvm5aw@slicealias.com>
Date: Thu, 20 Jul 2023 16:48:02 -0400
Subject: [PATCH] fix(battery): change nRF52 ADC gain

With ADC pin, maximum 3.6V input needs gain 1/6 to be less than the 0.6V
reference.

With VDDHDIV5, maximum 6V input corresponds to 1.2V so gain 1/2 will be less
than the 0.6V reference and be slightly more precise.
---
 app/drivers/sensor/battery/battery_nrf_vddh.c        | 2 +-
 app/drivers/sensor/battery/battery_voltage_divider.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/app/drivers/sensor/battery/battery_nrf_vddh.c b/app/drivers/sensor/battery/battery_nrf_vddh.c
index 3f230812..32c7c61e 100644
--- a/app/drivers/sensor/battery/battery_nrf_vddh.c
+++ b/app/drivers/sensor/battery/battery_nrf_vddh.c
@@ -93,7 +93,7 @@ static int vddh_init(const struct device *dev) {
 
 #ifdef CONFIG_ADC_NRFX_SAADC
     drv_data->acc = (struct adc_channel_cfg){
-        .gain = ADC_GAIN_1_5,
+        .gain = ADC_GAIN_1_2,
         .reference = ADC_REF_INTERNAL,
         .acquisition_time = ADC_ACQ_TIME(ADC_ACQ_TIME_MICROSECONDS, 40),
         .input_positive = SAADC_CH_PSELN_PSELN_VDDHDIV5,
diff --git a/app/drivers/sensor/battery/battery_voltage_divider.c b/app/drivers/sensor/battery/battery_voltage_divider.c
index 655af3db..62a02e9c 100644
--- a/app/drivers/sensor/battery/battery_voltage_divider.c
+++ b/app/drivers/sensor/battery/battery_voltage_divider.c
@@ -140,7 +140,7 @@ static int bvd_init(const struct device *dev) {
 
 #ifdef CONFIG_ADC_NRFX_SAADC
     drv_data->acc = (struct adc_channel_cfg){
-        .gain = ADC_GAIN_1_5,
+        .gain = ADC_GAIN_1_6,
         .reference = ADC_REF_INTERNAL,
         .acquisition_time = ADC_ACQ_TIME(ADC_ACQ_TIME_MICROSECONDS, 40),
         .input_positive = SAADC_CH_PSELP_PSELP_AnalogInput0 + drv_cfg->io_channel.channel,