In ast2600, ADC integrate dividing circuit at last input channel for
battery sensing. This patch use the dts property "battery-sensing" to
enable this feature makes the last channel of each adc can tolerance
higher voltage than reference voltage.
Signed-off-by: Billy Tsai <billy_tsai@xxxxxxxxxxxxxx>
---
drivers/iio/adc/aspeed_adc.c | 60 +++++++++++++++++++++++++++++++++---
1 file changed, 55 insertions(+), 5 deletions(-)
diff --git a/drivers/iio/adc/aspeed_adc.c b/drivers/iio/adc/aspeed_adc.c
index 7e674b607e36..6c7e2bb7b1ac 100644
--- a/drivers/iio/adc/aspeed_adc.c
+++ b/drivers/iio/adc/aspeed_adc.c
@@ -45,6 +45,9 @@
#define ASPEED_ADC_REF_VOLTAGE_1200mV FIELD_PREP(ASPEED_ADC_REF_VOLTAGE, 1)
#define ASPEED_ADC_REF_VOLTAGE_EXT_HIGH FIELD_PREP(ASPEED_ADC_REF_VOLTAGE, 2)
#define ASPEED_ADC_REF_VOLTAGE_EXT_LOW FIELD_PREP(ASPEED_ADC_REF_VOLTAGE, 3)
+#define ASPEED_ADC_BATTERY_SENSING_DIV BIT(6)
+#define ASPEED_ADC_BATTERY_SENSING_DIV_2_3 FIELD_PREP(ASPEED_ADC_BATTERY_SENSING_DIV, 0)
+#define ASPEED_ADC_BATTERY_SENSING_DIV_1_3 FIELD_PREP(ASPEED_ADC_BATTERY_SENSING_DIV, 1)
#define ASPEED_ADC_CTRL_INIT_RDY BIT(8)
#define ASPEED_ADC_CH7_MODE BIT(12)
#define ASPEED_ADC_CH7_NORMAL FIELD_PREP(ASPEED_ADC_CH7_MODE, 0)
@@ -76,6 +79,11 @@ struct aspeed_adc_model_data {
unsigned int num_channels;
};
+struct adc_gain {
+ u8 mult;
+ u8 div;
+};
+
struct aspeed_adc_data {
struct device *dev;
void __iomem *base;
@@ -87,6 +95,8 @@ struct aspeed_adc_data {
int vref;
u32 sample_period_ns;
int cv;
+ bool battery_sensing;
+ struct adc_gain battery_mode_gain;
};
#define ASPEED_CHAN(_idx, _data_reg_addr) { \
@@ -185,14 +195,38 @@ static int aspeed_adc_read_raw(struct iio_dev *indio_dev,
int *val, int *val2, long mask)
{
struct aspeed_adc_data *data = iio_priv(indio_dev);
+ u32 adc_engine_control_reg_val;
switch (mask) {
case IIO_CHAN_INFO_RAW:
- *val = readw(data->base + chan->address) + data->cv;
- if (*val < 0)
- *val = 0;
- else if (*val >= ASPEED_ADC_MAX_RAW_DATA)
- *val = ASPEED_ADC_MAX_RAW_DATA;
+ if (data->battery_sensing && chan->channel == 7) {
+ adc_engine_control_reg_val =
+ readl(data->base + ASPEED_REG_ENGINE_CONTROL);
+ writel(adc_engine_control_reg_val |
+ ASPEED_ADC_CH7_BATTERY |
+ ASPEED_ADC_BATTERY_SENSING_ENABLE,
+ data->base + ASPEED_REG_ENGINE_CONTROL);
+ /*
+ * After enable battery sensing mode need to wait some time for adc stable
+ * Experiment result is 1ms.
+ */
+ mdelay(1);
+ *val = readw(data->base + chan->address) + data->cv;
+ if (*val < 0)
+ *val = 0;
+ else if (*val >= ASPEED_ADC_MAX_RAW_DATA)
+ *val = ASPEED_ADC_MAX_RAW_DATA;
+ *val = (*val * data->battery_mode_gain.mult) /
+ data->battery_mode_gain.div;
+ writel(adc_engine_control_reg_val,
+ data->base + ASPEED_REG_ENGINE_CONTROL);
+ } else {
+ *val = readw(data->base + chan->address) + data->cv;
+ if (*val < 0)
+ *val = 0;
+ else if (*val >= ASPEED_ADC_MAX_RAW_DATA)
+ *val = ASPEED_ADC_MAX_RAW_DATA;
+ }
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
@@ -392,6 +426,22 @@ static int aspeed_adc_probe(struct platform_device *pdev)
if (ret)
goto vref_config_error;
+ if (of_find_property(data->dev->of_node, "battery-sensing", NULL)) {
+ if (model_data->version >= aspeed_adc_ast2600) {
+ data->battery_sensing = 1;
+ if (readl(data->base + ASPEED_REG_ENGINE_CONTROL) &
+ ASPEED_ADC_BATTERY_SENSING_DIV_1_3) {
+ data->battery_mode_gain.mult = 3;
+ data->battery_mode_gain.div = 1;
+ } else {
+ data->battery_mode_gain.mult = 3;
+ data->battery_mode_gain.div = 2;
+ }
+ } else
+ dev_warn(&pdev->dev,
+ "Failed to enable battey-sensing mode\n");
+ }
+
if (model_data->wait_init_sequence) {
adc_engine_control_reg_val =
readl(data->base + ASPEED_REG_ENGINE_CONTROL);
--
2.25.1
