Switch from polling to interrupt mode.
Successfully tested on a S905GXBB-based Odroid C2.
Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx>
---
v2:
- move enabling / disabling irq to meson_sar_adc_start_sample_engine /
meson_sar_adc_stop_sample_engine respectively
- move setting FIFO threshold for irq triggering to meson_sar_adc_hw_enable
to avoid a potential issue when uboot should be involved in system resume
- return IRQ_NONE if the interrupt can't be for us
- document interrupts property in DT documentation
---
.../bindings/iio/adc/amlogic,meson-saradc.txt | 2 +
drivers/iio/adc/meson_saradc.c | 56 ++++++++++++++++++++--
2 files changed, 53 insertions(+), 5 deletions(-)
diff --git a/Documentation/devicetree/bindings/iio/adc/amlogic,meson-saradc.txt b/Documentation/devicetree/bindings/iio/adc/amlogic,meson-saradc.txt
index f9e3ff2c..04718919 100644
--- a/Documentation/devicetree/bindings/iio/adc/amlogic,meson-saradc.txt
+++ b/Documentation/devicetree/bindings/iio/adc/amlogic,meson-saradc.txt
@@ -7,6 +7,7 @@ Required properties:
- "amlogic,meson-gxm-saradc" for GXM
along with the generic "amlogic,meson-saradc"
- reg: the physical base address and length of the registers
+- interrupts: the interrupt indicating end of sampling
- clocks: phandle and clock identifier (see clock-names)
- clock-names: mandatory clocks:
- "clkin" for the reference clock (typically XTAL)
@@ -23,6 +24,7 @@ Example:
compatible = "amlogic,meson-gxl-saradc", "amlogic,meson-saradc";
#io-channel-cells = <1>;
reg = <0x0 0x8680 0x0 0x34>;
+ interrupts = <GIC_SPI 73 IRQ_TYPE_EDGE_RISING>;
clocks = <&xtal>,
<&clkc CLKID_SAR_ADC>,
<&clkc CLKID_SANA>,
diff --git a/drivers/iio/adc/meson_saradc.c b/drivers/iio/adc/meson_saradc.c
index 89def603..9f186de2 100644
--- a/drivers/iio/adc/meson_saradc.c
+++ b/drivers/iio/adc/meson_saradc.c
@@ -18,7 +18,9 @@
#include <linux/io.h>
#include <linux/iio/iio.h>
#include <linux/module.h>
+#include <linux/interrupt.h>
#include <linux/of.h>
+#include <linux/of_irq.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
@@ -163,6 +165,7 @@
#define MESON_SAR_ADC_REG13_12BIT_CALIBRATION_MASK GENMASK(13, 8)
#define MESON_SAR_ADC_MAX_FIFO_SIZE 32
+#define MESON_SAR_ADC_TIMEOUT 100 /* ms */
#define MESON_SAR_ADC_CHAN(_chan) { \
.type = IIO_VOLTAGE, \
@@ -229,6 +232,7 @@ struct meson_sar_adc_priv {
struct clk_gate clk_gate;
struct clk *adc_div_clk;
struct clk_divider clk_div;
+ struct completion done;
};
static const struct regmap_config meson_sar_adc_regmap_config = {
@@ -274,11 +278,11 @@ static int meson_sar_adc_read_raw_sample(struct iio_dev *indio_dev,
int *val)
{
struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
- int ret, regval, fifo_chan, fifo_val, sum = 0, count = 0;
+ int regval, fifo_chan, fifo_val, sum = 0, count = 0;
- ret = meson_sar_adc_wait_busy_clear(indio_dev);
- if (ret)
- return ret;
+ if(!wait_for_completion_timeout(&priv->done,
+ msecs_to_jiffies(MESON_SAR_ADC_TIMEOUT)))
+ return -ETIMEDOUT;
while (meson_sar_adc_get_fifo_count(indio_dev) > 0 &&
count < MESON_SAR_ADC_MAX_FIFO_SIZE) {
@@ -378,6 +382,12 @@ static void meson_sar_adc_start_sample_engine(struct iio_dev *indio_dev)
{
struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
+ reinit_completion(&priv->done);
+
+ regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG0,
+ MESON_SAR_ADC_REG0_FIFO_IRQ_EN,
+ MESON_SAR_ADC_REG0_FIFO_IRQ_EN);
+
regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG0,
MESON_SAR_ADC_REG0_SAMPLE_ENGINE_ENABLE,
MESON_SAR_ADC_REG0_SAMPLE_ENGINE_ENABLE);
@@ -392,6 +402,9 @@ static void meson_sar_adc_stop_sample_engine(struct iio_dev *indio_dev)
struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG0,
+ MESON_SAR_ADC_REG0_FIFO_IRQ_EN, 0);
+
+ regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG0,
MESON_SAR_ADC_REG0_SAMPLING_STOP,
MESON_SAR_ADC_REG0_SAMPLING_STOP);
@@ -643,6 +656,7 @@ static int meson_sar_adc_hw_enable(struct iio_dev *indio_dev)
{
struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
int ret;
+ u32 regval;
ret = meson_sar_adc_lock(indio_dev);
if (ret)
@@ -667,6 +681,9 @@ static int meson_sar_adc_hw_enable(struct iio_dev *indio_dev)
goto err_sana_clk;
}
+ regval = FIELD_PREP(MESON_SAR_ADC_REG0_FIFO_CNT_IRQ_MASK, 1);
+ regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG0,
+ MESON_SAR_ADC_REG0_FIFO_CNT_IRQ_MASK, regval);
regmap_update_bits(priv->regmap, MESON_SAR_ADC_REG11,
MESON_SAR_ADC_REG11_BANDGAP_EN,
MESON_SAR_ADC_REG11_BANDGAP_EN);
@@ -728,6 +745,25 @@ static int meson_sar_adc_hw_disable(struct iio_dev *indio_dev)
return 0;
}
+static irqreturn_t meson_sar_adc_irq(int irq, void *data)
+{
+ struct iio_dev *indio_dev = data;
+ struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
+ unsigned int cnt, threshold;
+ u32 regval;
+
+ regmap_read(priv->regmap, MESON_SAR_ADC_REG0, ®val);
+ cnt = FIELD_GET(MESON_SAR_ADC_REG0_FIFO_COUNT_MASK, regval);
+ threshold = FIELD_GET(MESON_SAR_ADC_REG0_FIFO_CNT_IRQ_MASK, regval);
+
+ if (cnt < threshold)
+ return IRQ_NONE;
+
+ complete(&priv->done);
+
+ return IRQ_HANDLED;
+}
+
static const struct iio_info meson_sar_adc_iio_info = {
.read_raw = meson_sar_adc_iio_info_read_raw,
.driver_module = THIS_MODULE,
@@ -770,7 +806,7 @@ static int meson_sar_adc_probe(struct platform_device *pdev)
struct resource *res;
void __iomem *base;
const struct of_device_id *match;
- int ret;
+ int irq, ret;
indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*priv));
if (!indio_dev) {
@@ -779,6 +815,7 @@ static int meson_sar_adc_probe(struct platform_device *pdev)
}
priv = iio_priv(indio_dev);
+ init_completion(&priv->done);
match = of_match_device(meson_sar_adc_of_match, &pdev->dev);
priv->data = match->data;
@@ -797,6 +834,15 @@ static int meson_sar_adc_probe(struct platform_device *pdev)
if (IS_ERR(base))
return PTR_ERR(base);
+ irq = irq_of_parse_and_map(pdev->dev.of_node, 0);
+ if (!irq)
+ return -EINVAL;
+
+ ret = devm_request_irq(&pdev->dev, irq, meson_sar_adc_irq, IRQF_SHARED,
+ dev_name(&pdev->dev), indio_dev);
+ if (ret)
+ return ret;
+
priv->regmap = devm_regmap_init_mmio(&pdev->dev, base,
&meson_sar_adc_regmap_config);
if (IS_ERR(priv->regmap))
--
2.11.1
--
To unsubscribe from this list: send the line "unsubscribe linux-iio" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
