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path: root/drivers/iio/adc/aspeed_adc.c
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Diffstat (limited to 'drivers/iio/adc/aspeed_adc.c')
-rw-r--r--drivers/iio/adc/aspeed_adc.c26
1 files changed, 26 insertions, 0 deletions
diff --git a/drivers/iio/adc/aspeed_adc.c b/drivers/iio/adc/aspeed_adc.c
index e0ea411a0b2d..c02b23d675cb 100644
--- a/drivers/iio/adc/aspeed_adc.c
+++ b/drivers/iio/adc/aspeed_adc.c
@@ -22,6 +22,7 @@
#include <linux/iio/iio.h>
#include <linux/iio/driver.h>
+#include <linux/iopoll.h>
#define ASPEED_RESOLUTION_BITS 10
#define ASPEED_CLOCKS_PER_SAMPLE 12
@@ -38,11 +39,17 @@
#define ASPEED_ENGINE_ENABLE BIT(0)
+#define ASPEED_ADC_CTRL_INIT_RDY BIT(8)
+
+#define ASPEED_ADC_INIT_POLLING_TIME 500
+#define ASPEED_ADC_INIT_TIMEOUT 500000
+
struct aspeed_adc_model_data {
const char *model_name;
unsigned int min_sampling_rate; // Hz
unsigned int max_sampling_rate; // Hz
unsigned int vref_voltage; // mV
+ bool wait_init_sequence;
};
struct aspeed_adc_data {
@@ -211,6 +218,24 @@ static int aspeed_adc_probe(struct platform_device *pdev)
goto scaler_error;
}
+ model_data = of_device_get_match_data(&pdev->dev);
+
+ if (model_data->wait_init_sequence) {
+ /* Enable engine in normal mode. */
+ writel(ASPEED_OPERATION_MODE_NORMAL | ASPEED_ENGINE_ENABLE,
+ data->base + ASPEED_REG_ENGINE_CONTROL);
+
+ /* Wait for initial sequence complete. */
+ ret = readl_poll_timeout(data->base + ASPEED_REG_ENGINE_CONTROL,
+ adc_engine_control_reg_val,
+ adc_engine_control_reg_val &
+ ASPEED_ADC_CTRL_INIT_RDY,
+ ASPEED_ADC_INIT_POLLING_TIME,
+ ASPEED_ADC_INIT_TIMEOUT);
+ if (ret)
+ goto scaler_error;
+ }
+
/* Start all channels in normal mode. */
ret = clk_prepare_enable(data->clk_scaler->clk);
if (ret)
@@ -274,6 +299,7 @@ static const struct aspeed_adc_model_data ast2500_model_data = {
.vref_voltage = 1800, // mV
.min_sampling_rate = 1,
.max_sampling_rate = 1000000,
+ .wait_init_sequence = true,
};
static const struct of_device_id aspeed_adc_matches[] = {