2 files changed, 298 insertions, 21 deletions

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index e2a64fda99f6..69e6cc4b40bf 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -499,6 +499,8 @@ config STM32_ADC_CORE
 	depends on ARCH_STM32 || COMPILE_TEST
 	depends on OF
 	depends on REGULATOR
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
 	help
 	  Select this option to enable the core driver for STMicroelectronics
 	  STM32 analog-to-digital converter (ADC).
diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
index 5715e79f4935..1e382b6c1424 100644
--- a/drivers/iio/adc/stm32-adc.c
+++ b/drivers/iio/adc/stm32-adc.c
@@ -22,6 +22,10 @@
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/module.h>
@@ -58,21 +62,37 @@
 
 /* STM32F4_ADC_CR2 - bit fields */
 #define STM32F4_SWSTART			BIT(30)
+#define STM32F4_EXTEN_SHIFT		28
 #define STM32F4_EXTEN_MASK		GENMASK(29, 28)
+#define STM32F4_EXTSEL_SHIFT		24
+#define STM32F4_EXTSEL_MASK		GENMASK(27, 24)
 #define STM32F4_EOCS			BIT(10)
 #define STM32F4_ADON			BIT(0)
 
-/* STM32F4_ADC_SQR1 - bit fields */
-#define STM32F4_L_SHIFT			20
-#define STM32F4_L_MASK			GENMASK(23, 20)
-
-/* STM32F4_ADC_SQR3 - bit fields */
-#define STM32F4_SQ1_SHIFT		0
-#define STM32F4_SQ1_MASK		GENMASK(4, 0)
-
+#define STM32_ADC_MAX_SQ		16	/* SQ1..SQ16 */
 #define STM32_ADC_TIMEOUT_US		100000
 #define STM32_ADC_TIMEOUT	(msecs_to_jiffies(STM32_ADC_TIMEOUT_US / 1000))
 
+/* External trigger enable */
+enum stm32_adc_exten {
+	STM32_EXTEN_SWTRIG,
+	STM32_EXTEN_HWTRIG_RISING_EDGE,
+	STM32_EXTEN_HWTRIG_FALLING_EDGE,
+	STM32_EXTEN_HWTRIG_BOTH_EDGES,
+};
+
+/**
+ * stm32_adc_regs - stm32 ADC misc registers & bitfield desc
+ * @reg:		register offset
+ * @mask:		bitfield mask
+ * @shift:		left shift
+ */
+struct stm32_adc_regs {
+	int reg;
+	int mask;
+	int shift;
+};
+
 /**
  * struct stm32_adc - private data of each ADC IIO instance
  * @common:		reference to ADC block common data
@@ -82,15 +102,19 @@
  * @clk:		clock for this adc instance
  * @irq:		interrupt for this adc instance
  * @lock:		spinlock
+ * @bufi:		data buffer index
+ * @num_conv:		expected number of scan conversions
  */
 struct stm32_adc {
 	struct stm32_adc_common	*common;
 	u32			offset;
 	struct completion	completion;
-	u16			*buffer;
+	u16			buffer[STM32_ADC_MAX_SQ];
 	struct clk		*clk;
 	int			irq;
 	spinlock_t		lock;		/* interrupt lock */
+	unsigned int		bufi;
+	unsigned int		num_conv;
 };
 
 /**
@@ -126,6 +150,33 @@ static const struct stm32_adc_chan_spec stm32f4_adc123_channels[] = {
 };
 
 /**
+ * stm32f4_sq - describe regular sequence registers
+ * - L: sequence len (register & bit field)
+ * - SQ1..SQ16: sequence entries (register & bit field)
+ */
+static const struct stm32_adc_regs stm32f4_sq[STM32_ADC_MAX_SQ + 1] = {
+	/* L: len bit field description to be kept as first element */
+	{ STM32F4_ADC_SQR1, GENMASK(23, 20), 20 },
+	/* SQ1..SQ16 registers & bit fields (reg, mask, shift) */
+	{ STM32F4_ADC_SQR3, GENMASK(4, 0), 0 },
+	{ STM32F4_ADC_SQR3, GENMASK(9, 5), 5 },
+	{ STM32F4_ADC_SQR3, GENMASK(14, 10), 10 },
+	{ STM32F4_ADC_SQR3, GENMASK(19, 15), 15 },
+	{ STM32F4_ADC_SQR3, GENMASK(24, 20), 20 },
+	{ STM32F4_ADC_SQR3, GENMASK(29, 25), 25 },
+	{ STM32F4_ADC_SQR2, GENMASK(4, 0), 0 },
+	{ STM32F4_ADC_SQR2, GENMASK(9, 5), 5 },
+	{ STM32F4_ADC_SQR2, GENMASK(14, 10), 10 },
+	{ STM32F4_ADC_SQR2, GENMASK(19, 15), 15 },
+	{ STM32F4_ADC_SQR2, GENMASK(24, 20), 20 },
+	{ STM32F4_ADC_SQR2, GENMASK(29, 25), 25 },
+	{ STM32F4_ADC_SQR1, GENMASK(4, 0), 0 },
+	{ STM32F4_ADC_SQR1, GENMASK(9, 5), 5 },
+	{ STM32F4_ADC_SQR1, GENMASK(14, 10), 10 },
+	{ STM32F4_ADC_SQR1, GENMASK(19, 15), 15 },
+};
+
+/**
  * STM32 ADC registers access routines
  * @adc: stm32 adc instance
  * @reg: reg offset in adc instance
@@ -211,6 +262,104 @@ static void stm32_adc_stop_conv(struct stm32_adc *adc)
 }
 
 /**
+ * stm32_adc_conf_scan_seq() - Build regular channels scan sequence
+ * @indio_dev: IIO device
+ * @scan_mask: channels to be converted
+ *
+ * Conversion sequence :
+ * Configure ADC scan sequence based on selected channels in scan_mask.
+ * Add channels to SQR registers, from scan_mask LSB to MSB, then
+ * program sequence len.
+ */
+static int stm32_adc_conf_scan_seq(struct iio_dev *indio_dev,
+				   const unsigned long *scan_mask)
+{
+	struct stm32_adc *adc = iio_priv(indio_dev);
+	const struct iio_chan_spec *chan;
+	u32 val, bit;
+	int i = 0;
+
+	for_each_set_bit(bit, scan_mask, indio_dev->masklength) {
+		chan = indio_dev->channels + bit;
+		/*
+		 * Assign one channel per SQ entry in regular
+		 * sequence, starting with SQ1.
+		 */
+		i++;
+		if (i > STM32_ADC_MAX_SQ)
+			return -EINVAL;
+
+		dev_dbg(&indio_dev->dev, "%s chan %d to SQ%d\n",
+			__func__, chan->channel, i);
+
+		val = stm32_adc_readl(adc, stm32f4_sq[i].reg);
+		val &= ~stm32f4_sq[i].mask;
+		val |= chan->channel << stm32f4_sq[i].shift;
+		stm32_adc_writel(adc, stm32f4_sq[i].reg, val);
+	}
+
+	if (!i)
+		return -EINVAL;
+
+	/* Sequence len */
+	val = stm32_adc_readl(adc, stm32f4_sq[0].reg);
+	val &= ~stm32f4_sq[0].mask;
+	val |= ((i - 1) << stm32f4_sq[0].shift);
+	stm32_adc_writel(adc, stm32f4_sq[0].reg, val);
+
+	return 0;
+}
+
+/**
+ * stm32_adc_get_trig_extsel() - Get external trigger selection
+ * @trig: trigger
+ *
+ * Returns trigger extsel value, if trig matches, -EINVAL otherwise.
+ */
+static int stm32_adc_get_trig_extsel(struct iio_trigger *trig)
+{
+	return -EINVAL;
+}
+
+/**
+ * stm32_adc_set_trig() - Set a regular trigger
+ * @indio_dev: IIO device
+ * @trig: IIO trigger
+ *
+ * Set trigger source/polarity (e.g. SW, or HW with polarity) :
+ * - if HW trigger disabled (e.g. trig == NULL, conversion launched by sw)
+ * - if HW trigger enabled, set source & polarity
+ */
+static int stm32_adc_set_trig(struct iio_dev *indio_dev,
+			      struct iio_trigger *trig)
+{
+	struct stm32_adc *adc = iio_priv(indio_dev);
+	u32 val, extsel = 0, exten = STM32_EXTEN_SWTRIG;
+	unsigned long flags;
+	int ret;
+
+	if (trig) {
+		ret = stm32_adc_get_trig_extsel(trig);
+		if (ret < 0)
+			return ret;
+
+		/* set trigger source and polarity (default to rising edge) */
+		extsel = ret;
+		exten = STM32_EXTEN_HWTRIG_RISING_EDGE;
+	}
+
+	spin_lock_irqsave(&adc->lock, flags);
+	val = stm32_adc_readl(adc, STM32F4_ADC_CR2);
+	val &= ~(STM32F4_EXTEN_MASK | STM32F4_EXTSEL_MASK);
+	val |= exten << STM32F4_EXTEN_SHIFT;
+	val |= extsel << STM32F4_EXTSEL_SHIFT;
+	stm32_adc_writel(adc, STM32F4_ADC_CR2, val);
+	spin_unlock_irqrestore(&adc->lock, flags);
+
+	return 0;
+}
+
+/**
  * stm32_adc_single_conv() - Performs a single conversion
  * @indio_dev: IIO device
  * @chan: IIO channel
@@ -228,21 +377,20 @@ static int stm32_adc_single_conv(struct iio_dev *indio_dev,
 	struct stm32_adc *adc = iio_priv(indio_dev);
 	long timeout;
 	u32 val;
-	u16 result;
 	int ret;
 
 	reinit_completion(&adc->completion);
 
-	adc->buffer = &result;
+	adc->bufi = 0;
 
-	/* Program chan number in regular sequence */
-	val = stm32_adc_readl(adc, STM32F4_ADC_SQR3);
-	val &= ~STM32F4_SQ1_MASK;
-	val |= chan->channel << STM32F4_SQ1_SHIFT;
-	stm32_adc_writel(adc, STM32F4_ADC_SQR3, val);
+	/* Program chan number in regular sequence (SQ1) */
+	val = stm32_adc_readl(adc, stm32f4_sq[1].reg);
+	val &= ~stm32f4_sq[1].mask;
+	val |= chan->channel << stm32f4_sq[1].shift;
+	stm32_adc_writel(adc, stm32f4_sq[1].reg, val);
 
 	/* Set regular sequence len (0 for 1 conversion) */
-	stm32_adc_clr_bits(adc, STM32F4_ADC_SQR1, STM32F4_L_MASK);
+	stm32_adc_clr_bits(adc, stm32f4_sq[0].reg, stm32f4_sq[0].mask);
 
 	/* Trigger detection disabled (conversion can be launched in SW) */
 	stm32_adc_clr_bits(adc, STM32F4_ADC_CR2, STM32F4_EXTEN_MASK);
@@ -258,7 +406,7 @@ static int stm32_adc_single_conv(struct iio_dev *indio_dev,
 	} else if (timeout < 0) {
 		ret = timeout;
 	} else {
-		*res = result;
+		*res = adc->buffer[0];
 		ret = IIO_VAL_INT;
 	}
 
@@ -301,17 +449,56 @@ static int stm32_adc_read_raw(struct iio_dev *indio_dev,
 static irqreturn_t stm32_adc_isr(int irq, void *data)
 {
 	struct stm32_adc *adc = data;
+	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
 	u32 status = stm32_adc_readl(adc, STM32F4_ADC_SR);
 
 	if (status & STM32F4_EOC) {
-		*adc->buffer = stm32_adc_readw(adc, STM32F4_ADC_DR);
-		complete(&adc->completion);
+		/* Reading DR also clears EOC status flag */
+		adc->buffer[adc->bufi] = stm32_adc_readw(adc, STM32F4_ADC_DR);
+		if (iio_buffer_enabled(indio_dev)) {
+			adc->bufi++;
+			if (adc->bufi >= adc->num_conv) {
+				stm32_adc_conv_irq_disable(adc);
+				iio_trigger_poll(indio_dev->trig);
+			}
+		} else {
+			complete(&adc->completion);
+		}
 		return IRQ_HANDLED;
 	}
 
 	return IRQ_NONE;
 }
 
+/**
+ * stm32_adc_validate_trigger() - validate trigger for stm32 adc
+ * @indio_dev: IIO device
+ * @trig: new trigger
+ *
+ * Returns: 0 if trig matches one of the triggers registered by stm32 adc
+ * driver, -EINVAL otherwise.
+ */
+static int stm32_adc_validate_trigger(struct iio_dev *indio_dev,
+				      struct iio_trigger *trig)
+{
+	return stm32_adc_get_trig_extsel(trig) < 0 ? -EINVAL : 0;
+}
+
+static int stm32_adc_update_scan_mode(struct iio_dev *indio_dev,
+				      const unsigned long *scan_mask)
+{
+	struct stm32_adc *adc = iio_priv(indio_dev);
+	int ret;
+
+	adc->num_conv = bitmap_weight(scan_mask, indio_dev->masklength);
+
+	ret = stm32_adc_conf_scan_seq(indio_dev, scan_mask);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
 static int stm32_adc_of_xlate(struct iio_dev *indio_dev,
 			      const struct of_phandle_args *iiospec)
 {
@@ -350,11 +537,86 @@ static int stm32_adc_debugfs_reg_access(struct iio_dev *indio_dev,
 
 static const struct iio_info stm32_adc_iio_info = {
 	.read_raw = stm32_adc_read_raw,
+	.validate_trigger = stm32_adc_validate_trigger,
+	.update_scan_mode = stm32_adc_update_scan_mode,
 	.debugfs_reg_access = stm32_adc_debugfs_reg_access,
 	.of_xlate = stm32_adc_of_xlate,
 	.driver_module = THIS_MODULE,
 };
 
+static int stm32_adc_buffer_postenable(struct iio_dev *indio_dev)
+{
+	struct stm32_adc *adc = iio_priv(indio_dev);
+	int ret;
+
+	ret = stm32_adc_set_trig(indio_dev, indio_dev->trig);
+	if (ret) {
+		dev_err(&indio_dev->dev, "Can't set trigger\n");
+		return ret;
+	}
+
+	ret = iio_triggered_buffer_postenable(indio_dev);
+	if (ret < 0)
+		goto err_clr_trig;
+
+	/* Reset adc buffer index */
+	adc->bufi = 0;
+
+	stm32_adc_conv_irq_enable(adc);
+	stm32_adc_start_conv(adc);
+
+	return 0;
+
+err_clr_trig:
+	stm32_adc_set_trig(indio_dev, NULL);
+
+	return ret;
+}
+
+static int stm32_adc_buffer_predisable(struct iio_dev *indio_dev)
+{
+	struct stm32_adc *adc = iio_priv(indio_dev);
+	int ret;
+
+	stm32_adc_stop_conv(adc);
+	stm32_adc_conv_irq_disable(adc);
+
+	ret = iio_triggered_buffer_predisable(indio_dev);
+	if (ret < 0)
+		dev_err(&indio_dev->dev, "predisable failed\n");
+
+	if (stm32_adc_set_trig(indio_dev, NULL))
+		dev_err(&indio_dev->dev, "Can't clear trigger\n");
+
+	return ret;
+}
+
+static const struct iio_buffer_setup_ops stm32_adc_buffer_setup_ops = {
+	.postenable = &stm32_adc_buffer_postenable,
+	.predisable = &stm32_adc_buffer_predisable,
+};
+
+static irqreturn_t stm32_adc_trigger_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct stm32_adc *adc = iio_priv(indio_dev);
+
+	dev_dbg(&indio_dev->dev, "%s bufi=%d\n", __func__, adc->bufi);
+
+	/* reset buffer index */
+	adc->bufi = 0;
+	iio_push_to_buffers_with_timestamp(indio_dev, adc->buffer,
+					   pf->timestamp);
+
+	iio_trigger_notify_done(indio_dev->trig);
+
+	/* re-enable eoc irq */
+	stm32_adc_conv_irq_enable(adc);
+
+	return IRQ_HANDLED;
+}
+
 static void stm32_adc_chan_init_one(struct iio_dev *indio_dev,
 				    struct iio_chan_spec *chan,
 				    const struct stm32_adc_chan_spec *channel,
@@ -471,14 +733,26 @@ static int stm32_adc_probe(struct platform_device *pdev)
 	if (ret < 0)
 		goto err_clk_disable;
 
+	ret = iio_triggered_buffer_setup(indio_dev,
+					 &iio_pollfunc_store_time,
+					 &stm32_adc_trigger_handler,
+					 &stm32_adc_buffer_setup_ops);
+	if (ret) {
+		dev_err(&pdev->dev, "buffer setup failed\n");
+		goto err_clk_disable;
+	}
+
 	ret = iio_device_register(indio_dev);
 	if (ret) {
 		dev_err(&pdev->dev, "iio dev register failed\n");
-		goto err_clk_disable;
+		goto err_buffer_cleanup;
 	}
 
 	return 0;
 
+err_buffer_cleanup:
+	iio_triggered_buffer_cleanup(indio_dev);
+
 err_clk_disable:
 	clk_disable_unprepare(adc->clk);
 
@@ -491,6 +765,7 @@ static int stm32_adc_remove(struct platform_device *pdev)
 	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
 
 	iio_device_unregister(indio_dev);
+	iio_triggered_buffer_cleanup(indio_dev);
 	clk_disable_unprepare(adc->clk);
 
 	return 0;