Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1934 insertions, 0 deletions

diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
new file mode 100644
index 000000000..59fd8b620
--- /dev/null
+++ b/drivers/iio/adc/stm32-adc.c
@@ -0,0 +1,1934 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This file is part of STM32 ADC driver
+ *
+ * Copyright (C) 2016, STMicroelectronics - All Rights Reserved
+ * Author: Fabrice Gasnier <fabrice.gasnier@st.com>.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmaengine.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/timer/stm32-lptim-trigger.h>
+#include <linux/iio/timer/stm32-timer-trigger.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/iopoll.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+
+#include "stm32-adc-core.h"
+
+/* Number of linear calibration shadow registers / LINCALRDYW control bits */
+#define STM32H7_LINCALFACT_NUM		6
+
+/* BOOST bit must be set on STM32H7 when ADC clock is above 20MHz */
+#define STM32H7_BOOST_CLKRATE		20000000UL
+
+#define STM32_ADC_CH_MAX		20	/* max number of channels */
+#define STM32_ADC_CH_SZ			10	/* max channel name size */
+#define STM32_ADC_MAX_SQ		16	/* SQ1..SQ16 */
+#define STM32_ADC_MAX_SMP		7	/* SMPx range is [0..7] */
+#define STM32_ADC_TIMEOUT_US		100000
+#define STM32_ADC_TIMEOUT	(msecs_to_jiffies(STM32_ADC_TIMEOUT_US / 1000))
+
+#define STM32_DMA_BUFFER_SIZE		PAGE_SIZE
+
+/* 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,
+};
+
+/* extsel - trigger mux selection value */
+enum stm32_adc_extsel {
+	STM32_EXT0,
+	STM32_EXT1,
+	STM32_EXT2,
+	STM32_EXT3,
+	STM32_EXT4,
+	STM32_EXT5,
+	STM32_EXT6,
+	STM32_EXT7,
+	STM32_EXT8,
+	STM32_EXT9,
+	STM32_EXT10,
+	STM32_EXT11,
+	STM32_EXT12,
+	STM32_EXT13,
+	STM32_EXT14,
+	STM32_EXT15,
+	STM32_EXT16,
+	STM32_EXT17,
+	STM32_EXT18,
+	STM32_EXT19,
+	STM32_EXT20,
+};
+
+/**
+ * struct stm32_adc_trig_info - ADC trigger info
+ * @name:		name of the trigger, corresponding to its source
+ * @extsel:		trigger selection
+ */
+struct stm32_adc_trig_info {
+	const char *name;
+	enum stm32_adc_extsel extsel;
+};
+
+/**
+ * struct stm32_adc_calib - optional adc calibration data
+ * @calfact_s: Calibration offset for single ended channels
+ * @calfact_d: Calibration offset in differential
+ * @lincalfact: Linearity calibration factor
+ */
+struct stm32_adc_calib {
+	u32			calfact_s;
+	u32			calfact_d;
+	u32			lincalfact[STM32H7_LINCALFACT_NUM];
+};
+
+/**
+ * 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;
+};
+
+/**
+ * stm32_adc_regspec - stm32 registers definition, compatible dependent data
+ * @dr:			data register offset
+ * @ier_eoc:		interrupt enable register & eocie bitfield
+ * @isr_eoc:		interrupt status register & eoc bitfield
+ * @sqr:		reference to sequence registers array
+ * @exten:		trigger control register & bitfield
+ * @extsel:		trigger selection register & bitfield
+ * @res:		resolution selection register & bitfield
+ * @smpr:		smpr1 & smpr2 registers offset array
+ * @smp_bits:		smpr1 & smpr2 index and bitfields
+ */
+struct stm32_adc_regspec {
+	const u32 dr;
+	const struct stm32_adc_regs ier_eoc;
+	const struct stm32_adc_regs isr_eoc;
+	const struct stm32_adc_regs *sqr;
+	const struct stm32_adc_regs exten;
+	const struct stm32_adc_regs extsel;
+	const struct stm32_adc_regs res;
+	const u32 smpr[2];
+	const struct stm32_adc_regs *smp_bits;
+};
+
+struct stm32_adc;
+
+/**
+ * stm32_adc_cfg - stm32 compatible configuration data
+ * @regs:		registers descriptions
+ * @adc_info:		per instance input channels definitions
+ * @trigs:		external trigger sources
+ * @clk_required:	clock is required
+ * @has_vregready:	vregready status flag presence
+ * @selfcalib:		optional routine for self-calibration
+ * @prepare:		optional prepare routine (power-up, enable)
+ * @start_conv:		routine to start conversions
+ * @stop_conv:		routine to stop conversions
+ * @unprepare:		optional unprepare routine (disable, power-down)
+ * @smp_cycles:		programmable sampling time (ADC clock cycles)
+ */
+struct stm32_adc_cfg {
+	const struct stm32_adc_regspec	*regs;
+	const struct stm32_adc_info	*adc_info;
+	struct stm32_adc_trig_info	*trigs;
+	bool clk_required;
+	bool has_vregready;
+	int (*selfcalib)(struct stm32_adc *);
+	int (*prepare)(struct stm32_adc *);
+	void (*start_conv)(struct stm32_adc *, bool dma);
+	void (*stop_conv)(struct stm32_adc *);
+	void (*unprepare)(struct stm32_adc *);
+	const unsigned int *smp_cycles;
+};
+
+/**
+ * struct stm32_adc - private data of each ADC IIO instance
+ * @common:		reference to ADC block common data
+ * @offset:		ADC instance register offset in ADC block
+ * @cfg:		compatible configuration data
+ * @completion:		end of single conversion completion
+ * @buffer:		data buffer
+ * @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
+ * @res:		data resolution (e.g. RES bitfield value)
+ * @trigger_polarity:	external trigger polarity (e.g. exten)
+ * @dma_chan:		dma channel
+ * @rx_buf:		dma rx buffer cpu address
+ * @rx_dma_buf:		dma rx buffer bus address
+ * @rx_buf_sz:		dma rx buffer size
+ * @difsel		bitmask to set single-ended/differential channel
+ * @pcsel		bitmask to preselect channels on some devices
+ * @smpr_val:		sampling time settings (e.g. smpr1 / smpr2)
+ * @cal:		optional calibration data on some devices
+ * @chan_name:		channel name array
+ */
+struct stm32_adc {
+	struct stm32_adc_common	*common;
+	u32			offset;
+	const struct stm32_adc_cfg	*cfg;
+	struct completion	completion;
+	u16			buffer[STM32_ADC_MAX_SQ];
+	struct clk		*clk;
+	int			irq;
+	spinlock_t		lock;		/* interrupt lock */
+	unsigned int		bufi;
+	unsigned int		num_conv;
+	u32			res;
+	u32			trigger_polarity;
+	struct dma_chan		*dma_chan;
+	u8			*rx_buf;
+	dma_addr_t		rx_dma_buf;
+	unsigned int		rx_buf_sz;
+	u32			difsel;
+	u32			pcsel;
+	u32			smpr_val[2];
+	struct stm32_adc_calib	cal;
+	char			chan_name[STM32_ADC_CH_MAX][STM32_ADC_CH_SZ];
+};
+
+struct stm32_adc_diff_channel {
+	u32 vinp;
+	u32 vinn;
+};
+
+/**
+ * struct stm32_adc_info - stm32 ADC, per instance config data
+ * @max_channels:	Number of channels
+ * @resolutions:	available resolutions
+ * @num_res:		number of available resolutions
+ */
+struct stm32_adc_info {
+	int max_channels;
+	const unsigned int *resolutions;
+	const unsigned int num_res;
+};
+
+static const unsigned int stm32f4_adc_resolutions[] = {
+	/* sorted values so the index matches RES[1:0] in STM32F4_ADC_CR1 */
+	12, 10, 8, 6,
+};
+
+/* stm32f4 can have up to 16 channels */
+static const struct stm32_adc_info stm32f4_adc_info = {
+	.max_channels = 16,
+	.resolutions = stm32f4_adc_resolutions,
+	.num_res = ARRAY_SIZE(stm32f4_adc_resolutions),
+};
+
+static const unsigned int stm32h7_adc_resolutions[] = {
+	/* sorted values so the index matches RES[2:0] in STM32H7_ADC_CFGR */
+	16, 14, 12, 10, 8,
+};
+
+/* stm32h7 can have up to 20 channels */
+static const struct stm32_adc_info stm32h7_adc_info = {
+	.max_channels = STM32_ADC_CH_MAX,
+	.resolutions = stm32h7_adc_resolutions,
+	.num_res = ARRAY_SIZE(stm32h7_adc_resolutions),
+};
+
+/**
+ * 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 },
+};
+
+/* STM32F4 external trigger sources for all instances */
+static struct stm32_adc_trig_info stm32f4_adc_trigs[] = {
+	{ TIM1_CH1, STM32_EXT0 },
+	{ TIM1_CH2, STM32_EXT1 },
+	{ TIM1_CH3, STM32_EXT2 },
+	{ TIM2_CH2, STM32_EXT3 },
+	{ TIM2_CH3, STM32_EXT4 },
+	{ TIM2_CH4, STM32_EXT5 },
+	{ TIM2_TRGO, STM32_EXT6 },
+	{ TIM3_CH1, STM32_EXT7 },
+	{ TIM3_TRGO, STM32_EXT8 },
+	{ TIM4_CH4, STM32_EXT9 },
+	{ TIM5_CH1, STM32_EXT10 },
+	{ TIM5_CH2, STM32_EXT11 },
+	{ TIM5_CH3, STM32_EXT12 },
+	{ TIM8_CH1, STM32_EXT13 },
+	{ TIM8_TRGO, STM32_EXT14 },
+	{}, /* sentinel */
+};
+
+/**
+ * stm32f4_smp_bits[] - describe sampling time register index & bit fields
+ * Sorted so it can be indexed by channel number.
+ */
+static const struct stm32_adc_regs stm32f4_smp_bits[] = {
+	/* STM32F4_ADC_SMPR2: smpr[] index, mask, shift for SMP0 to SMP9 */
+	{ 1, GENMASK(2, 0), 0 },
+	{ 1, GENMASK(5, 3), 3 },
+	{ 1, GENMASK(8, 6), 6 },
+	{ 1, GENMASK(11, 9), 9 },
+	{ 1, GENMASK(14, 12), 12 },
+	{ 1, GENMASK(17, 15), 15 },
+	{ 1, GENMASK(20, 18), 18 },
+	{ 1, GENMASK(23, 21), 21 },
+	{ 1, GENMASK(26, 24), 24 },
+	{ 1, GENMASK(29, 27), 27 },
+	/* STM32F4_ADC_SMPR1, smpr[] index, mask, shift for SMP10 to SMP18 */
+	{ 0, GENMASK(2, 0), 0 },
+	{ 0, GENMASK(5, 3), 3 },
+	{ 0, GENMASK(8, 6), 6 },
+	{ 0, GENMASK(11, 9), 9 },
+	{ 0, GENMASK(14, 12), 12 },
+	{ 0, GENMASK(17, 15), 15 },
+	{ 0, GENMASK(20, 18), 18 },
+	{ 0, GENMASK(23, 21), 21 },
+	{ 0, GENMASK(26, 24), 24 },
+};
+
+/* STM32F4 programmable sampling time (ADC clock cycles) */
+static const unsigned int stm32f4_adc_smp_cycles[STM32_ADC_MAX_SMP + 1] = {
+	3, 15, 28, 56, 84, 112, 144, 480,
+};
+
+static const struct stm32_adc_regspec stm32f4_adc_regspec = {
+	.dr = STM32F4_ADC_DR,
+	.ier_eoc = { STM32F4_ADC_CR1, STM32F4_EOCIE },
+	.isr_eoc = { STM32F4_ADC_SR, STM32F4_EOC },
+	.sqr = stm32f4_sq,
+	.exten = { STM32F4_ADC_CR2, STM32F4_EXTEN_MASK, STM32F4_EXTEN_SHIFT },
+	.extsel = { STM32F4_ADC_CR2, STM32F4_EXTSEL_MASK,
+		    STM32F4_EXTSEL_SHIFT },
+	.res = { STM32F4_ADC_CR1, STM32F4_RES_MASK, STM32F4_RES_SHIFT },
+	.smpr = { STM32F4_ADC_SMPR1, STM32F4_ADC_SMPR2 },
+	.smp_bits = stm32f4_smp_bits,
+};
+
+static const struct stm32_adc_regs stm32h7_sq[STM32_ADC_MAX_SQ + 1] = {
+	/* L: len bit field description to be kept as first element */
+	{ STM32H7_ADC_SQR1, GENMASK(3, 0), 0 },
+	/* SQ1..SQ16 registers & bit fields (reg, mask, shift) */
+	{ STM32H7_ADC_SQR1, GENMASK(10, 6), 6 },
+	{ STM32H7_ADC_SQR1, GENMASK(16, 12), 12 },
+	{ STM32H7_ADC_SQR1, GENMASK(22, 18), 18 },
+	{ STM32H7_ADC_SQR1, GENMASK(28, 24), 24 },
+	{ STM32H7_ADC_SQR2, GENMASK(4, 0), 0 },
+	{ STM32H7_ADC_SQR2, GENMASK(10, 6), 6 },
+	{ STM32H7_ADC_SQR2, GENMASK(16, 12), 12 },
+	{ STM32H7_ADC_SQR2, GENMASK(22, 18), 18 },
+	{ STM32H7_ADC_SQR2, GENMASK(28, 24), 24 },
+	{ STM32H7_ADC_SQR3, GENMASK(4, 0), 0 },
+	{ STM32H7_ADC_SQR3, GENMASK(10, 6), 6 },
+	{ STM32H7_ADC_SQR3, GENMASK(16, 12), 12 },
+	{ STM32H7_ADC_SQR3, GENMASK(22, 18), 18 },
+	{ STM32H7_ADC_SQR3, GENMASK(28, 24), 24 },
+	{ STM32H7_ADC_SQR4, GENMASK(4, 0), 0 },
+	{ STM32H7_ADC_SQR4, GENMASK(10, 6), 6 },
+};
+
+/* STM32H7 external trigger sources for all instances */
+static struct stm32_adc_trig_info stm32h7_adc_trigs[] = {
+	{ TIM1_CH1, STM32_EXT0 },
+	{ TIM1_CH2, STM32_EXT1 },
+	{ TIM1_CH3, STM32_EXT2 },
+	{ TIM2_CH2, STM32_EXT3 },
+	{ TIM3_TRGO, STM32_EXT4 },
+	{ TIM4_CH4, STM32_EXT5 },
+	{ TIM8_TRGO, STM32_EXT7 },
+	{ TIM8_TRGO2, STM32_EXT8 },
+	{ TIM1_TRGO, STM32_EXT9 },
+	{ TIM1_TRGO2, STM32_EXT10 },
+	{ TIM2_TRGO, STM32_EXT11 },
+	{ TIM4_TRGO, STM32_EXT12 },
+	{ TIM6_TRGO, STM32_EXT13 },
+	{ TIM15_TRGO, STM32_EXT14 },
+	{ TIM3_CH4, STM32_EXT15 },
+	{ LPTIM1_OUT, STM32_EXT18 },
+	{ LPTIM2_OUT, STM32_EXT19 },
+	{ LPTIM3_OUT, STM32_EXT20 },
+	{},
+};
+
+/**
+ * stm32h7_smp_bits - describe sampling time register index & bit fields
+ * Sorted so it can be indexed by channel number.
+ */
+static const struct stm32_adc_regs stm32h7_smp_bits[] = {
+	/* STM32H7_ADC_SMPR1, smpr[] index, mask, shift for SMP0 to SMP9 */
+	{ 0, GENMASK(2, 0), 0 },
+	{ 0, GENMASK(5, 3), 3 },
+	{ 0, GENMASK(8, 6), 6 },
+	{ 0, GENMASK(11, 9), 9 },
+	{ 0, GENMASK(14, 12), 12 },
+	{ 0, GENMASK(17, 15), 15 },
+	{ 0, GENMASK(20, 18), 18 },
+	{ 0, GENMASK(23, 21), 21 },
+	{ 0, GENMASK(26, 24), 24 },
+	{ 0, GENMASK(29, 27), 27 },
+	/* STM32H7_ADC_SMPR2, smpr[] index, mask, shift for SMP10 to SMP19 */
+	{ 1, GENMASK(2, 0), 0 },
+	{ 1, GENMASK(5, 3), 3 },
+	{ 1, GENMASK(8, 6), 6 },
+	{ 1, GENMASK(11, 9), 9 },
+	{ 1, GENMASK(14, 12), 12 },
+	{ 1, GENMASK(17, 15), 15 },
+	{ 1, GENMASK(20, 18), 18 },
+	{ 1, GENMASK(23, 21), 21 },
+	{ 1, GENMASK(26, 24), 24 },
+	{ 1, GENMASK(29, 27), 27 },
+};
+
+/* STM32H7 programmable sampling time (ADC clock cycles, rounded down) */
+static const unsigned int stm32h7_adc_smp_cycles[STM32_ADC_MAX_SMP + 1] = {
+	1, 2, 8, 16, 32, 64, 387, 810,
+};
+
+static const struct stm32_adc_regspec stm32h7_adc_regspec = {
+	.dr = STM32H7_ADC_DR,
+	.ier_eoc = { STM32H7_ADC_IER, STM32H7_EOCIE },
+	.isr_eoc = { STM32H7_ADC_ISR, STM32H7_EOC },
+	.sqr = stm32h7_sq,
+	.exten = { STM32H7_ADC_CFGR, STM32H7_EXTEN_MASK, STM32H7_EXTEN_SHIFT },
+	.extsel = { STM32H7_ADC_CFGR, STM32H7_EXTSEL_MASK,
+		    STM32H7_EXTSEL_SHIFT },
+	.res = { STM32H7_ADC_CFGR, STM32H7_RES_MASK, STM32H7_RES_SHIFT },
+	.smpr = { STM32H7_ADC_SMPR1, STM32H7_ADC_SMPR2 },
+	.smp_bits = stm32h7_smp_bits,
+};
+
+/**
+ * STM32 ADC registers access routines
+ * @adc: stm32 adc instance
+ * @reg: reg offset in adc instance
+ *
+ * Note: All instances share same base, with 0x0, 0x100 or 0x200 offset resp.
+ * for adc1, adc2 and adc3.
+ */
+static u32 stm32_adc_readl(struct stm32_adc *adc, u32 reg)
+{
+	return readl_relaxed(adc->common->base + adc->offset + reg);
+}
+
+#define stm32_adc_readl_addr(addr)	stm32_adc_readl(adc, addr)
+
+#define stm32_adc_readl_poll_timeout(reg, val, cond, sleep_us, timeout_us) \
+	readx_poll_timeout(stm32_adc_readl_addr, reg, val, \
+			   cond, sleep_us, timeout_us)
+
+static u16 stm32_adc_readw(struct stm32_adc *adc, u32 reg)
+{
+	return readw_relaxed(adc->common->base + adc->offset + reg);
+}
+
+static void stm32_adc_writel(struct stm32_adc *adc, u32 reg, u32 val)
+{
+	writel_relaxed(val, adc->common->base + adc->offset + reg);
+}
+
+static void stm32_adc_set_bits(struct stm32_adc *adc, u32 reg, u32 bits)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&adc->lock, flags);
+	stm32_adc_writel(adc, reg, stm32_adc_readl(adc, reg) | bits);
+	spin_unlock_irqrestore(&adc->lock, flags);
+}
+
+static void stm32_adc_clr_bits(struct stm32_adc *adc, u32 reg, u32 bits)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&adc->lock, flags);
+	stm32_adc_writel(adc, reg, stm32_adc_readl(adc, reg) & ~bits);
+	spin_unlock_irqrestore(&adc->lock, flags);
+}
+
+/**
+ * stm32_adc_conv_irq_enable() - Enable end of conversion interrupt
+ * @adc: stm32 adc instance
+ */
+static void stm32_adc_conv_irq_enable(struct stm32_adc *adc)
+{
+	stm32_adc_set_bits(adc, adc->cfg->regs->ier_eoc.reg,
+			   adc->cfg->regs->ier_eoc.mask);
+};
+
+/**
+ * stm32_adc_conv_irq_disable() - Disable end of conversion interrupt
+ * @adc: stm32 adc instance
+ */
+static void stm32_adc_conv_irq_disable(struct stm32_adc *adc)
+{
+	stm32_adc_clr_bits(adc, adc->cfg->regs->ier_eoc.reg,
+			   adc->cfg->regs->ier_eoc.mask);
+}
+
+static void stm32_adc_set_res(struct stm32_adc *adc)
+{
+	const struct stm32_adc_regs *res = &adc->cfg->regs->res;
+	u32 val;
+
+	val = stm32_adc_readl(adc, res->reg);
+	val = (val & ~res->mask) | (adc->res << res->shift);
+	stm32_adc_writel(adc, res->reg, val);
+}
+
+/**
+ * stm32f4_adc_start_conv() - Start conversions for regular channels.
+ * @adc: stm32 adc instance
+ * @dma: use dma to transfer conversion result
+ *
+ * Start conversions for regular channels.
+ * Also take care of normal or DMA mode. Circular DMA may be used for regular
+ * conversions, in IIO buffer modes. Otherwise, use ADC interrupt with direct
+ * DR read instead (e.g. read_raw, or triggered buffer mode without DMA).
+ */
+static void stm32f4_adc_start_conv(struct stm32_adc *adc, bool dma)
+{
+	stm32_adc_set_bits(adc, STM32F4_ADC_CR1, STM32F4_SCAN);
+
+	if (dma)
+		stm32_adc_set_bits(adc, STM32F4_ADC_CR2,
+				   STM32F4_DMA | STM32F4_DDS);
+
+	stm32_adc_set_bits(adc, STM32F4_ADC_CR2, STM32F4_EOCS | STM32F4_ADON);
+
+	/* Wait for Power-up time (tSTAB from datasheet) */
+	usleep_range(2, 3);
+
+	/* Software start ? (e.g. trigger detection disabled ?) */
+	if (!(stm32_adc_readl(adc, STM32F4_ADC_CR2) & STM32F4_EXTEN_MASK))
+		stm32_adc_set_bits(adc, STM32F4_ADC_CR2, STM32F4_SWSTART);
+}
+
+static void stm32f4_adc_stop_conv(struct stm32_adc *adc)
+{
+	stm32_adc_clr_bits(adc, STM32F4_ADC_CR2, STM32F4_EXTEN_MASK);
+	stm32_adc_clr_bits(adc, STM32F4_ADC_SR, STM32F4_STRT);
+
+	stm32_adc_clr_bits(adc, STM32F4_ADC_CR1, STM32F4_SCAN);
+	stm32_adc_clr_bits(adc, STM32F4_ADC_CR2,
+			   STM32F4_ADON | STM32F4_DMA | STM32F4_DDS);
+}
+
+static void stm32h7_adc_start_conv(struct stm32_adc *adc, bool dma)
+{
+	enum stm32h7_adc_dmngt dmngt;
+	unsigned long flags;
+	u32 val;
+
+	if (dma)
+		dmngt = STM32H7_DMNGT_DMA_CIRC;
+	else
+		dmngt = STM32H7_DMNGT_DR_ONLY;
+
+	spin_lock_irqsave(&adc->lock, flags);
+	val = stm32_adc_readl(adc, STM32H7_ADC_CFGR);
+	val = (val & ~STM32H7_DMNGT_MASK) | (dmngt << STM32H7_DMNGT_SHIFT);
+	stm32_adc_writel(adc, STM32H7_ADC_CFGR, val);
+	spin_unlock_irqrestore(&adc->lock, flags);
+
+	stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADSTART);
+}
+
+static void stm32h7_adc_stop_conv(struct stm32_adc *adc)
+{
+	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
+	int ret;
+	u32 val;
+
+	stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADSTP);
+
+	ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val,
+					   !(val & (STM32H7_ADSTART)),
+					   100, STM32_ADC_TIMEOUT_US);
+	if (ret)
+		dev_warn(&indio_dev->dev, "stop failed\n");
+
+	stm32_adc_clr_bits(adc, STM32H7_ADC_CFGR, STM32H7_DMNGT_MASK);
+}
+
+static int stm32h7_adc_exit_pwr_down(struct stm32_adc *adc)
+{
+	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
+	int ret;
+	u32 val;
+
+	/* Exit deep power down, then enable ADC voltage regulator */
+	stm32_adc_clr_bits(adc, STM32H7_ADC_CR, STM32H7_DEEPPWD);
+	stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADVREGEN);
+
+	if (adc->common->rate > STM32H7_BOOST_CLKRATE)
+		stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_BOOST);
+
+	/* Wait for startup time */
+	if (!adc->cfg->has_vregready) {
+		usleep_range(10, 20);
+		return 0;
+	}
+
+	ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_ISR, val,
+					   val & STM32MP1_VREGREADY, 100,
+					   STM32_ADC_TIMEOUT_US);
+	if (ret) {
+		stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_DEEPPWD);
+		dev_err(&indio_dev->dev, "Failed to exit power down\n");
+	}
+
+	return ret;
+}
+
+static void stm32h7_adc_enter_pwr_down(struct stm32_adc *adc)
+{
+	stm32_adc_clr_bits(adc, STM32H7_ADC_CR, STM32H7_BOOST);
+
+	/* Setting DEEPPWD disables ADC vreg and clears ADVREGEN */
+	stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_DEEPPWD);
+}
+
+static int stm32h7_adc_enable(struct stm32_adc *adc)
+{
+	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
+	int ret;
+	u32 val;
+
+	stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADEN);
+
+	/* Poll for ADRDY to be set (after adc startup time) */
+	ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_ISR, val,
+					   val & STM32H7_ADRDY,
+					   100, STM32_ADC_TIMEOUT_US);
+	if (ret) {
+		stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADDIS);
+		dev_err(&indio_dev->dev, "Failed to enable ADC\n");
+	} else {
+		/* Clear ADRDY by writing one */
+		stm32_adc_set_bits(adc, STM32H7_ADC_ISR, STM32H7_ADRDY);
+	}
+
+	return ret;
+}
+
+static void stm32h7_adc_disable(struct stm32_adc *adc)
+{
+	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
+	int ret;
+	u32 val;
+
+	/* Disable ADC and wait until it's effectively disabled */
+	stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADDIS);
+	ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val,
+					   !(val & STM32H7_ADEN), 100,
+					   STM32_ADC_TIMEOUT_US);
+	if (ret)
+		dev_warn(&indio_dev->dev, "Failed to disable\n");
+}
+
+/**
+ * stm32h7_adc_read_selfcalib() - read calibration shadow regs, save result
+ * @adc: stm32 adc instance
+ */
+static int stm32h7_adc_read_selfcalib(struct stm32_adc *adc)
+{
+	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
+	int i, ret;
+	u32 lincalrdyw_mask, val;
+
+	/* Enable adc so LINCALRDYW1..6 bits are writable */
+	ret = stm32h7_adc_enable(adc);
+	if (ret)
+		return ret;
+
+	/* Read linearity calibration */
+	lincalrdyw_mask = STM32H7_LINCALRDYW6;
+	for (i = STM32H7_LINCALFACT_NUM - 1; i >= 0; i--) {
+		/* Clear STM32H7_LINCALRDYW[6..1]: transfer calib to CALFACT2 */
+		stm32_adc_clr_bits(adc, STM32H7_ADC_CR, lincalrdyw_mask);
+
+		/* Poll: wait calib data to be ready in CALFACT2 register */
+		ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val,
+						   !(val & lincalrdyw_mask),
+						   100, STM32_ADC_TIMEOUT_US);
+		if (ret) {
+			dev_err(&indio_dev->dev, "Failed to read calfact\n");
+			goto disable;
+		}
+
+		val = stm32_adc_readl(adc, STM32H7_ADC_CALFACT2);
+		adc->cal.lincalfact[i] = (val & STM32H7_LINCALFACT_MASK);
+		adc->cal.lincalfact[i] >>= STM32H7_LINCALFACT_SHIFT;
+
+		lincalrdyw_mask >>= 1;
+	}
+
+	/* Read offset calibration */
+	val = stm32_adc_readl(adc, STM32H7_ADC_CALFACT);
+	adc->cal.calfact_s = (val & STM32H7_CALFACT_S_MASK);
+	adc->cal.calfact_s >>= STM32H7_CALFACT_S_SHIFT;
+	adc->cal.calfact_d = (val & STM32H7_CALFACT_D_MASK);
+	adc->cal.calfact_d >>= STM32H7_CALFACT_D_SHIFT;
+
+disable:
+	stm32h7_adc_disable(adc);
+
+	return ret;
+}
+
+/**
+ * stm32h7_adc_restore_selfcalib() - Restore saved self-calibration result
+ * @adc: stm32 adc instance
+ * Note: ADC must be enabled, with no on-going conversions.
+ */
+static int stm32h7_adc_restore_selfcalib(struct stm32_adc *adc)
+{
+	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
+	int i, ret;
+	u32 lincalrdyw_mask, val;
+
+	val = (adc->cal.calfact_s << STM32H7_CALFACT_S_SHIFT) |
+		(adc->cal.calfact_d << STM32H7_CALFACT_D_SHIFT);
+	stm32_adc_writel(adc, STM32H7_ADC_CALFACT, val);
+
+	lincalrdyw_mask = STM32H7_LINCALRDYW6;
+	for (i = STM32H7_LINCALFACT_NUM - 1; i >= 0; i--) {
+		/*
+		 * Write saved calibration data to shadow registers:
+		 * Write CALFACT2, and set LINCALRDYW[6..1] bit to trigger
+		 * data write. Then poll to wait for complete transfer.
+		 */
+		val = adc->cal.lincalfact[i] << STM32H7_LINCALFACT_SHIFT;
+		stm32_adc_writel(adc, STM32H7_ADC_CALFACT2, val);
+		stm32_adc_set_bits(adc, STM32H7_ADC_CR, lincalrdyw_mask);
+		ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val,
+						   val & lincalrdyw_mask,
+						   100, STM32_ADC_TIMEOUT_US);
+		if (ret) {
+			dev_err(&indio_dev->dev, "Failed to write calfact\n");
+			return ret;
+		}
+
+		/*
+		 * Read back calibration data, has two effects:
+		 * - It ensures bits LINCALRDYW[6..1] are kept cleared
+		 *   for next time calibration needs to be restored.
+		 * - BTW, bit clear triggers a read, then check data has been
+		 *   correctly written.
+		 */
+		stm32_adc_clr_bits(adc, STM32H7_ADC_CR, lincalrdyw_mask);
+		ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val,
+						   !(val & lincalrdyw_mask),
+						   100, STM32_ADC_TIMEOUT_US);
+		if (ret) {
+			dev_err(&indio_dev->dev, "Failed to read calfact\n");
+			return ret;
+		}
+		val = stm32_adc_readl(adc, STM32H7_ADC_CALFACT2);
+		if (val != adc->cal.lincalfact[i] << STM32H7_LINCALFACT_SHIFT) {
+			dev_err(&indio_dev->dev, "calfact not consistent\n");
+			return -EIO;
+		}
+
+		lincalrdyw_mask >>= 1;
+	}
+
+	return 0;
+}
+
+/**
+ * Fixed timeout value for ADC calibration.
+ * worst cases:
+ * - low clock frequency
+ * - maximum prescalers
+ * Calibration requires:
+ * - 131,072 ADC clock cycle for the linear calibration
+ * - 20 ADC clock cycle for the offset calibration
+ *
+ * Set to 100ms for now
+ */
+#define STM32H7_ADC_CALIB_TIMEOUT_US		100000
+
+/**
+ * stm32h7_adc_selfcalib() - Procedure to calibrate ADC (from power down)
+ * @adc: stm32 adc instance
+ * Exit from power down, calibrate ADC, then return to power down.
+ */
+static int stm32h7_adc_selfcalib(struct stm32_adc *adc)
+{
+	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
+	int ret;
+	u32 val;
+
+	ret = stm32h7_adc_exit_pwr_down(adc);
+	if (ret)
+		return ret;
+
+	/*
+	 * Select calibration mode:
+	 * - Offset calibration for single ended inputs
+	 * - No linearity calibration (do it later, before reading it)
+	 */
+	stm32_adc_clr_bits(adc, STM32H7_ADC_CR, STM32H7_ADCALDIF);
+	stm32_adc_clr_bits(adc, STM32H7_ADC_CR, STM32H7_ADCALLIN);
+
+	/* Start calibration, then wait for completion */
+	stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADCAL);
+	ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val,
+					   !(val & STM32H7_ADCAL), 100,
+					   STM32H7_ADC_CALIB_TIMEOUT_US);
+	if (ret) {
+		dev_err(&indio_dev->dev, "calibration failed\n");
+		goto pwr_dwn;
+	}
+
+	/*
+	 * Select calibration mode, then start calibration:
+	 * - Offset calibration for differential input
+	 * - Linearity calibration (needs to be done only once for single/diff)
+	 *   will run simultaneously with offset calibration.
+	 */
+	stm32_adc_set_bits(adc, STM32H7_ADC_CR,
+			   STM32H7_ADCALDIF | STM32H7_ADCALLIN);
+	stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADCAL);
+	ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val,
+					   !(val & STM32H7_ADCAL), 100,
+					   STM32H7_ADC_CALIB_TIMEOUT_US);
+	if (ret) {
+		dev_err(&indio_dev->dev, "calibration failed\n");
+		goto pwr_dwn;
+	}
+
+	stm32_adc_clr_bits(adc, STM32H7_ADC_CR,
+			   STM32H7_ADCALDIF | STM32H7_ADCALLIN);
+
+	/* Read calibration result for future reference */
+	ret = stm32h7_adc_read_selfcalib(adc);
+
+pwr_dwn:
+	stm32h7_adc_enter_pwr_down(adc);
+
+	return ret;
+}
+
+/**
+ * stm32h7_adc_prepare() - Leave power down mode to enable ADC.
+ * @adc: stm32 adc instance
+ * Leave power down mode.
+ * Configure channels as single ended or differential before enabling ADC.
+ * Enable ADC.
+ * Restore calibration data.
+ * Pre-select channels that may be used in PCSEL (required by input MUX / IO):
+ * - Only one input is selected for single ended (e.g. 'vinp')
+ * - Two inputs are selected for differential channels (e.g. 'vinp' & 'vinn')
+ */
+static int stm32h7_adc_prepare(struct stm32_adc *adc)
+{
+	int ret;
+
+	ret = stm32h7_adc_exit_pwr_down(adc);
+	if (ret)
+		return ret;
+
+	stm32_adc_writel(adc, STM32H7_ADC_DIFSEL, adc->difsel);
+
+	ret = stm32h7_adc_enable(adc);
+	if (ret)
+		goto pwr_dwn;
+
+	ret = stm32h7_adc_restore_selfcalib(adc);
+	if (ret)
+		goto disable;
+
+	stm32_adc_writel(adc, STM32H7_ADC_PCSEL, adc->pcsel);
+
+	return 0;
+
+disable:
+	stm32h7_adc_disable(adc);
+pwr_dwn:
+	stm32h7_adc_enter_pwr_down(adc);
+
+	return ret;
+}
+
+static void stm32h7_adc_unprepare(struct stm32_adc *adc)
+{
+	stm32h7_adc_disable(adc);
+	stm32h7_adc_enter_pwr_down(adc);
+}
+
+/**
+ * stm32_adc_conf_scan_seq() - Build regular channels scan sequence
+ * @indio_dev: IIO device
+ * @scan_mask: channels to be converted
+ *
+ * Conversion sequence :
+ * Apply sampling time settings for all channels.
+ * 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 stm32_adc_regs *sqr = adc->cfg->regs->sqr;
+	const struct iio_chan_spec *chan;
+	u32 val, bit;
+	int i = 0;
+
+	/* Apply sampling time settings */
+	stm32_adc_writel(adc, adc->cfg->regs->smpr[0], adc->smpr_val[0]);
+	stm32_adc_writel(adc, adc->cfg->regs->smpr[1], adc->smpr_val[1]);
+
+	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, sqr[i].reg);
+		val &= ~sqr[i].mask;
+		val |= chan->channel << sqr[i].shift;
+		stm32_adc_writel(adc, sqr[i].reg, val);
+	}
+
+	if (!i)
+		return -EINVAL;
+
+	/* Sequence len */
+	val = stm32_adc_readl(adc, sqr[0].reg);
+	val &= ~sqr[0].mask;
+	val |= ((i - 1) << sqr[0].shift);
+	stm32_adc_writel(adc, sqr[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_dev *indio_dev,
+				     struct iio_trigger *trig)
+{
+	struct stm32_adc *adc = iio_priv(indio_dev);
+	int i;
+
+	/* lookup triggers registered by stm32 timer trigger driver */
+	for (i = 0; adc->cfg->trigs[i].name; i++) {
+		/**
+		 * Checking both stm32 timer trigger type and trig name
+		 * should be safe against arbitrary trigger names.
+		 */
+		if ((is_stm32_timer_trigger(trig) ||
+		     is_stm32_lptim_trigger(trig)) &&
+		    !strcmp(adc->cfg->trigs[i].name, trig->name)) {
+			return adc->cfg->trigs[i].extsel;
+		}
+	}
+
+	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(indio_dev, trig);
+		if (ret < 0)
+			return ret;
+
+		/* set trigger source and polarity (default to rising edge) */
+		extsel = ret;
+		exten = adc->trigger_polarity + STM32_EXTEN_HWTRIG_RISING_EDGE;
+	}
+
+	spin_lock_irqsave(&adc->lock, flags);
+	val = stm32_adc_readl(adc, adc->cfg->regs->exten.reg);
+	val &= ~(adc->cfg->regs->exten.mask | adc->cfg->regs->extsel.mask);
+	val |= exten << adc->cfg->regs->exten.shift;
+	val |= extsel << adc->cfg->regs->extsel.shift;
+	stm32_adc_writel(adc,  adc->cfg->regs->exten.reg, val);
+	spin_unlock_irqrestore(&adc->lock, flags);
+
+	return 0;
+}
+
+static int stm32_adc_set_trig_pol(struct iio_dev *indio_dev,
+				  const struct iio_chan_spec *chan,
+				  unsigned int type)
+{
+	struct stm32_adc *adc = iio_priv(indio_dev);
+
+	adc->trigger_polarity = type;
+
+	return 0;
+}
+
+static int stm32_adc_get_trig_pol(struct iio_dev *indio_dev,
+				  const struct iio_chan_spec *chan)
+{
+	struct stm32_adc *adc = iio_priv(indio_dev);
+
+	return adc->trigger_polarity;
+}
+
+static const char * const stm32_trig_pol_items[] = {
+	"rising-edge", "falling-edge", "both-edges",
+};
+
+static const struct iio_enum stm32_adc_trig_pol = {
+	.items = stm32_trig_pol_items,
+	.num_items = ARRAY_SIZE(stm32_trig_pol_items),
+	.get = stm32_adc_get_trig_pol,
+	.set = stm32_adc_set_trig_pol,
+};
+
+/**
+ * stm32_adc_single_conv() - Performs a single conversion
+ * @indio_dev: IIO device
+ * @chan: IIO channel
+ * @res: conversion result
+ *
+ * The function performs a single conversion on a given channel:
+ * - Apply sampling time settings
+ * - Program sequencer with one channel (e.g. in SQ1 with len = 1)
+ * - Use SW trigger
+ * - Start conversion, then wait for interrupt completion.
+ */
+static int stm32_adc_single_conv(struct iio_dev *indio_dev,
+				 const struct iio_chan_spec *chan,
+				 int *res)
+{
+	struct stm32_adc *adc = iio_priv(indio_dev);
+	const struct stm32_adc_regspec *regs = adc->cfg->regs;
+	long timeout;
+	u32 val;
+	int ret;
+
+	reinit_completion(&adc->completion);
+
+	adc->bufi = 0;
+
+	if (adc->cfg->prepare) {
+		ret = adc->cfg->prepare(adc);
+		if (ret)
+			return ret;
+	}
+
+	/* Apply sampling time settings */
+	stm32_adc_writel(adc, regs->smpr[0], adc->smpr_val[0]);
+	stm32_adc_writel(adc, regs->smpr[1], adc->smpr_val[1]);
+
+	/* Program chan number in regular sequence (SQ1) */
+	val = stm32_adc_readl(adc, regs->sqr[1].reg);
+	val &= ~regs->sqr[1].mask;
+	val |= chan->channel << regs->sqr[1].shift;
+	stm32_adc_writel(adc, regs->sqr[1].reg, val);
+
+	/* Set regular sequence len (0 for 1 conversion) */
+	stm32_adc_clr_bits(adc, regs->sqr[0].reg, regs->sqr[0].mask);
+
+	/* Trigger detection disabled (conversion can be launched in SW) */
+	stm32_adc_clr_bits(adc, regs->exten.reg, regs->exten.mask);
+
+	stm32_adc_conv_irq_enable(adc);
+
+	adc->cfg->start_conv(adc, false);
+
+	timeout = wait_for_completion_interruptible_timeout(
+					&adc->completion, STM32_ADC_TIMEOUT);
+	if (timeout == 0) {
+		ret = -ETIMEDOUT;
+	} else if (timeout < 0) {
+		ret = timeout;
+	} else {
+		*res = adc->buffer[0];
+		ret = IIO_VAL_INT;
+	}
+
+	adc->cfg->stop_conv(adc);
+
+	stm32_adc_conv_irq_disable(adc);
+
+	if (adc->cfg->unprepare)
+		adc->cfg->unprepare(adc);
+
+	return ret;
+}
+
+static int stm32_adc_read_raw(struct iio_dev *indio_dev,
+			      struct iio_chan_spec const *chan,
+			      int *val, int *val2, long mask)
+{
+	struct stm32_adc *adc = iio_priv(indio_dev);
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = iio_device_claim_direct_mode(indio_dev);
+		if (ret)
+			return ret;
+		if (chan->type == IIO_VOLTAGE)
+			ret = stm32_adc_single_conv(indio_dev, chan, val);
+		else
+			ret = -EINVAL;
+		iio_device_release_direct_mode(indio_dev);
+		return ret;
+
+	case IIO_CHAN_INFO_SCALE:
+		if (chan->differential) {
+			*val = adc->common->vref_mv * 2;
+			*val2 = chan->scan_type.realbits;
+		} else {
+			*val = adc->common->vref_mv;
+			*val2 = chan->scan_type.realbits;
+		}
+		return IIO_VAL_FRACTIONAL_LOG2;
+
+	case IIO_CHAN_INFO_OFFSET:
+		if (chan->differential)
+			/* ADC_full_scale / 2 */
+			*val = -((1 << chan->scan_type.realbits) / 2);
+		else
+			*val = 0;
+		return IIO_VAL_INT;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+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);
+	const struct stm32_adc_regspec *regs = adc->cfg->regs;
+	u32 status = stm32_adc_readl(adc, regs->isr_eoc.reg);
+
+	if (status & regs->isr_eoc.mask) {
+		/* Reading DR also clears EOC status flag */
+		adc->buffer[adc->bufi] = stm32_adc_readw(adc, regs->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(indio_dev, trig) < 0 ? -EINVAL : 0;
+}
+
+static int stm32_adc_set_watermark(struct iio_dev *indio_dev, unsigned int val)
+{
+	struct stm32_adc *adc = iio_priv(indio_dev);
+	unsigned int watermark = STM32_DMA_BUFFER_SIZE / 2;
+	unsigned int rx_buf_sz = STM32_DMA_BUFFER_SIZE;
+
+	/*
+	 * dma cyclic transfers are used, buffer is split into two periods.
+	 * There should be :
+	 * - always one buffer (period) dma is working on
+	 * - one buffer (period) driver can push with iio_trigger_poll().
+	 */
+	watermark = min(watermark, val * (unsigned)(sizeof(u16)));
+	adc->rx_buf_sz = min(rx_buf_sz, watermark * 2 * adc->num_conv);
+
+	return 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)
+{
+	int i;
+
+	for (i = 0; i < indio_dev->num_channels; i++)
+		if (indio_dev->channels[i].channel == iiospec->args[0])
+			return i;
+
+	return -EINVAL;
+}
+
+/**
+ * stm32_adc_debugfs_reg_access - read or write register value
+ *
+ * To read a value from an ADC register:
+ *   echo [ADC reg offset] > direct_reg_access
+ *   cat direct_reg_access
+ *
+ * To write a value in a ADC register:
+ *   echo [ADC_reg_offset] [value] > direct_reg_access
+ */
+static int stm32_adc_debugfs_reg_access(struct iio_dev *indio_dev,
+					unsigned reg, unsigned writeval,
+					unsigned *readval)
+{
+	struct stm32_adc *adc = iio_priv(indio_dev);
+
+	if (!readval)
+		stm32_adc_writel(adc, reg, writeval);
+	else
+		*readval = stm32_adc_readl(adc, reg);
+
+	return 0;
+}
+
+static const struct iio_info stm32_adc_iio_info = {
+	.read_raw = stm32_adc_read_raw,
+	.validate_trigger = stm32_adc_validate_trigger,
+	.hwfifo_set_watermark = stm32_adc_set_watermark,
+	.update_scan_mode = stm32_adc_update_scan_mode,
+	.debugfs_reg_access = stm32_adc_debugfs_reg_access,
+	.of_xlate = stm32_adc_of_xlate,
+};
+
+static unsigned int stm32_adc_dma_residue(struct stm32_adc *adc)
+{
+	struct dma_tx_state state;
+	enum dma_status status;
+
+	status = dmaengine_tx_status(adc->dma_chan,
+				     adc->dma_chan->cookie,
+				     &state);
+	if (status == DMA_IN_PROGRESS) {
+		/* Residue is size in bytes from end of buffer */
+		unsigned int i = adc->rx_buf_sz - state.residue;
+		unsigned int size;
+
+		/* Return available bytes */
+		if (i >= adc->bufi)
+			size = i - adc->bufi;
+		else
+			size = adc->rx_buf_sz + i - adc->bufi;
+
+		return size;
+	}
+
+	return 0;
+}
+
+static void stm32_adc_dma_buffer_done(void *data)
+{
+	struct iio_dev *indio_dev = data;
+	struct stm32_adc *adc = iio_priv(indio_dev);
+	int residue = stm32_adc_dma_residue(adc);
+
+	/*
+	 * In DMA mode the trigger services of IIO are not used
+	 * (e.g. no call to iio_trigger_poll).
+	 * Calling irq handler associated to the hardware trigger is not
+	 * relevant as the conversions have already been done. Data
+	 * transfers are performed directly in DMA callback instead.
+	 * This implementation avoids to call trigger irq handler that
+	 * may sleep, in an atomic context (DMA irq handler context).
+	 */
+	dev_dbg(&indio_dev->dev, "%s bufi=%d\n", __func__, adc->bufi);
+
+	while (residue >= indio_dev->scan_bytes) {
+		u16 *buffer = (u16 *)&adc->rx_buf[adc->bufi];
+
+		iio_push_to_buffers(indio_dev, buffer);
+
+		residue -= indio_dev->scan_bytes;
+		adc->bufi += indio_dev->scan_bytes;
+		if (adc->bufi >= adc->rx_buf_sz)
+			adc->bufi = 0;
+	}
+}
+
+static int stm32_adc_dma_start(struct iio_dev *indio_dev)
+{
+	struct stm32_adc *adc = iio_priv(indio_dev);
+	struct dma_async_tx_descriptor *desc;
+	dma_cookie_t cookie;
+	int ret;
+
+	if (!adc->dma_chan)
+		return 0;
+
+	dev_dbg(&indio_dev->dev, "%s size=%d watermark=%d\n", __func__,
+		adc->rx_buf_sz, adc->rx_buf_sz / 2);
+
+	/* Prepare a DMA cyclic transaction */
+	desc = dmaengine_prep_dma_cyclic(adc->dma_chan,
+					 adc->rx_dma_buf,
+					 adc->rx_buf_sz, adc->rx_buf_sz / 2,
+					 DMA_DEV_TO_MEM,
+					 DMA_PREP_INTERRUPT);
+	if (!desc)
+		return -EBUSY;
+
+	desc->callback = stm32_adc_dma_buffer_done;
+	desc->callback_param = indio_dev;
+
+	cookie = dmaengine_submit(desc);
+	ret = dma_submit_error(cookie);
+	if (ret) {
+		dmaengine_terminate_sync(adc->dma_chan);
+		return ret;
+	}
+
+	/* Issue pending DMA requests */
+	dma_async_issue_pending(adc->dma_chan);
+
+	return 0;
+}
+
+static int stm32_adc_buffer_postenable(struct iio_dev *indio_dev)
+{
+	struct stm32_adc *adc = iio_priv(indio_dev);
+	int ret;
+
+	if (adc->cfg->prepare) {
+		ret = adc->cfg->prepare(adc);
+		if (ret)
+			return ret;
+	}
+
+	ret = stm32_adc_set_trig(indio_dev, indio_dev->trig);
+	if (ret) {
+		dev_err(&indio_dev->dev, "Can't set trigger\n");
+		goto err_unprepare;
+	}
+
+	ret = stm32_adc_dma_start(indio_dev);
+	if (ret) {
+		dev_err(&indio_dev->dev, "Can't start dma\n");
+		goto err_clr_trig;
+	}
+
+	ret = iio_triggered_buffer_postenable(indio_dev);
+	if (ret < 0)
+		goto err_stop_dma;
+
+	/* Reset adc buffer index */
+	adc->bufi = 0;
+
+	if (!adc->dma_chan)
+		stm32_adc_conv_irq_enable(adc);
+
+	adc->cfg->start_conv(adc, !!adc->dma_chan);
+
+	return 0;
+
+err_stop_dma:
+	if (adc->dma_chan)
+		dmaengine_terminate_all(adc->dma_chan);
+err_clr_trig:
+	stm32_adc_set_trig(indio_dev, NULL);
+err_unprepare:
+	if (adc->cfg->unprepare)
+		adc->cfg->unprepare(adc);
+
+	return ret;
+}
+
+static int stm32_adc_buffer_predisable(struct iio_dev *indio_dev)
+{
+	struct stm32_adc *adc = iio_priv(indio_dev);
+	int ret;
+
+	adc->cfg->stop_conv(adc);
+	if (!adc->dma_chan)
+		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 (adc->dma_chan)
+		dmaengine_terminate_sync(adc->dma_chan);
+
+	if (stm32_adc_set_trig(indio_dev, NULL))
+		dev_err(&indio_dev->dev, "Can't clear trigger\n");
+
+	if (adc->cfg->unprepare)
+		adc->cfg->unprepare(adc);
+
+	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);
+
+	if (!adc->dma_chan) {
+		/* reset buffer index */
+		adc->bufi = 0;
+		iio_push_to_buffers_with_timestamp(indio_dev, adc->buffer,
+						   pf->timestamp);
+	} else {
+		int residue = stm32_adc_dma_residue(adc);
+
+		while (residue >= indio_dev->scan_bytes) {
+			u16 *buffer = (u16 *)&adc->rx_buf[adc->bufi];
+
+			iio_push_to_buffers_with_timestamp(indio_dev, buffer,
+							   pf->timestamp);
+			residue -= indio_dev->scan_bytes;
+			adc->bufi += indio_dev->scan_bytes;
+			if (adc->bufi >= adc->rx_buf_sz)
+				adc->bufi = 0;
+		}
+	}
+
+	iio_trigger_notify_done(indio_dev->trig);
+
+	/* re-enable eoc irq */
+	if (!adc->dma_chan)
+		stm32_adc_conv_irq_enable(adc);
+
+	return IRQ_HANDLED;
+}
+
+static const struct iio_chan_spec_ext_info stm32_adc_ext_info[] = {
+	IIO_ENUM("trigger_polarity", IIO_SHARED_BY_ALL, &stm32_adc_trig_pol),
+	{
+		.name = "trigger_polarity_available",
+		.shared = IIO_SHARED_BY_ALL,
+		.read = iio_enum_available_read,
+		.private = (uintptr_t)&stm32_adc_trig_pol,
+	},
+	{},
+};
+
+static int stm32_adc_of_get_resolution(struct iio_dev *indio_dev)
+{
+	struct device_node *node = indio_dev->dev.of_node;
+	struct stm32_adc *adc = iio_priv(indio_dev);
+	unsigned int i;
+	u32 res;
+
+	if (of_property_read_u32(node, "assigned-resolution-bits", &res))
+		res = adc->cfg->adc_info->resolutions[0];
+
+	for (i = 0; i < adc->cfg->adc_info->num_res; i++)
+		if (res == adc->cfg->adc_info->resolutions[i])
+			break;
+	if (i >= adc->cfg->adc_info->num_res) {
+		dev_err(&indio_dev->dev, "Bad resolution: %u bits\n", res);
+		return -EINVAL;
+	}
+
+	dev_dbg(&indio_dev->dev, "Using %u bits resolution\n", res);
+	adc->res = i;
+
+	return 0;
+}
+
+static void stm32_adc_smpr_init(struct stm32_adc *adc, int channel, u32 smp_ns)
+{
+	const struct stm32_adc_regs *smpr = &adc->cfg->regs->smp_bits[channel];
+	u32 period_ns, shift = smpr->shift, mask = smpr->mask;
+	unsigned int smp, r = smpr->reg;
+
+	/* Determine sampling time (ADC clock cycles) */
+	period_ns = NSEC_PER_SEC / adc->common->rate;
+	for (smp = 0; smp <= STM32_ADC_MAX_SMP; smp++)
+		if ((period_ns * adc->cfg->smp_cycles[smp]) >= smp_ns)
+			break;
+	if (smp > STM32_ADC_MAX_SMP)
+		smp = STM32_ADC_MAX_SMP;
+
+	/* pre-build sampling time registers (e.g. smpr1, smpr2) */
+	adc->smpr_val[r] = (adc->smpr_val[r] & ~mask) | (smp << shift);
+}
+
+static void stm32_adc_chan_init_one(struct iio_dev *indio_dev,
+				    struct iio_chan_spec *chan, u32 vinp,
+				    u32 vinn, int scan_index, bool differential)
+{
+	struct stm32_adc *adc = iio_priv(indio_dev);
+	char *name = adc->chan_name[vinp];
+
+	chan->type = IIO_VOLTAGE;
+	chan->channel = vinp;
+	if (differential) {
+		chan->differential = 1;
+		chan->channel2 = vinn;
+		snprintf(name, STM32_ADC_CH_SZ, "in%d-in%d", vinp, vinn);
+	} else {
+		snprintf(name, STM32_ADC_CH_SZ, "in%d", vinp);
+	}
+	chan->datasheet_name = name;
+	chan->scan_index = scan_index;
+	chan->indexed = 1;
+	chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
+	chan->info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |
+					 BIT(IIO_CHAN_INFO_OFFSET);
+	chan->scan_type.sign = 'u';
+	chan->scan_type.realbits = adc->cfg->adc_info->resolutions[adc->res];
+	chan->scan_type.storagebits = 16;
+	chan->ext_info = stm32_adc_ext_info;
+
+	/* pre-build selected channels mask */
+	adc->pcsel |= BIT(chan->channel);
+	if (differential) {
+		/* pre-build diff channels mask */
+		adc->difsel |= BIT(chan->channel);
+		/* Also add negative input to pre-selected channels */
+		adc->pcsel |= BIT(chan->channel2);
+	}
+}
+
+static int stm32_adc_chan_of_init(struct iio_dev *indio_dev)
+{
+	struct device_node *node = indio_dev->dev.of_node;
+	struct stm32_adc *adc = iio_priv(indio_dev);
+	const struct stm32_adc_info *adc_info = adc->cfg->adc_info;
+	struct stm32_adc_diff_channel diff[STM32_ADC_CH_MAX];
+	struct property *prop;
+	const __be32 *cur;
+	struct iio_chan_spec *channels;
+	int scan_index = 0, num_channels = 0, num_diff = 0, ret, i;
+	u32 val, smp = 0;
+
+	ret = of_property_count_u32_elems(node, "st,adc-channels");
+	if (ret > adc_info->max_channels) {
+		dev_err(&indio_dev->dev, "Bad st,adc-channels?\n");
+		return -EINVAL;
+	} else if (ret > 0) {
+		num_channels += ret;
+	}
+
+	ret = of_property_count_elems_of_size(node, "st,adc-diff-channels",
+					      sizeof(*diff));
+	if (ret > adc_info->max_channels) {
+		dev_err(&indio_dev->dev, "Bad st,adc-diff-channels?\n");
+		return -EINVAL;
+	} else if (ret > 0) {
+		int size = ret * sizeof(*diff) / sizeof(u32);
+
+		num_diff = ret;
+		num_channels += ret;
+		ret = of_property_read_u32_array(node, "st,adc-diff-channels",
+						 (u32 *)diff, size);
+		if (ret)
+			return ret;
+	}
+
+	if (!num_channels) {
+		dev_err(&indio_dev->dev, "No channels configured\n");
+		return -ENODATA;
+	}
+
+	/* Optional sample time is provided either for each, or all channels */
+	ret = of_property_count_u32_elems(node, "st,min-sample-time-nsecs");
+	if (ret > 1 && ret != num_channels) {
+		dev_err(&indio_dev->dev, "Invalid st,min-sample-time-nsecs\n");
+		return -EINVAL;
+	}
+
+	channels = devm_kcalloc(&indio_dev->dev, num_channels,
+				sizeof(struct iio_chan_spec), GFP_KERNEL);
+	if (!channels)
+		return -ENOMEM;
+
+	of_property_for_each_u32(node, "st,adc-channels", prop, cur, val) {
+		if (val >= adc_info->max_channels) {
+			dev_err(&indio_dev->dev, "Invalid channel %d\n", val);
+			return -EINVAL;
+		}
+
+		/* Channel can't be configured both as single-ended & diff */
+		for (i = 0; i < num_diff; i++) {
+			if (val == diff[i].vinp) {
+				dev_err(&indio_dev->dev,
+					"channel %d miss-configured\n",	val);
+				return -EINVAL;
+			}
+		}
+		stm32_adc_chan_init_one(indio_dev, &channels[scan_index], val,
+					0, scan_index, false);
+		scan_index++;
+	}
+
+	for (i = 0; i < num_diff; i++) {
+		if (diff[i].vinp >= adc_info->max_channels ||
+		    diff[i].vinn >= adc_info->max_channels) {
+			dev_err(&indio_dev->dev, "Invalid channel in%d-in%d\n",
+				diff[i].vinp, diff[i].vinn);
+			return -EINVAL;
+		}
+		stm32_adc_chan_init_one(indio_dev, &channels[scan_index],
+					diff[i].vinp, diff[i].vinn, scan_index,
+					true);
+		scan_index++;
+	}
+
+	for (i = 0; i < scan_index; i++) {
+		/*
+		 * Using of_property_read_u32_index(), smp value will only be
+		 * modified if valid u32 value can be decoded. This allows to
+		 * get either no value, 1 shared value for all indexes, or one
+		 * value per channel.
+		 */
+		of_property_read_u32_index(node, "st,min-sample-time-nsecs",
+					   i, &smp);
+		/* Prepare sampling time settings */
+		stm32_adc_smpr_init(adc, channels[i].channel, smp);
+	}
+
+	indio_dev->num_channels = scan_index;
+	indio_dev->channels = channels;
+
+	return 0;
+}
+
+static int stm32_adc_dma_request(struct device *dev, struct iio_dev *indio_dev)
+{
+	struct stm32_adc *adc = iio_priv(indio_dev);
+	struct dma_slave_config config;
+	int ret;
+
+	adc->dma_chan = dma_request_chan(dev, "rx");
+	if (IS_ERR(adc->dma_chan)) {
+		ret = PTR_ERR(adc->dma_chan);
+		if (ret != -ENODEV) {
+			if (ret != -EPROBE_DEFER)
+				dev_err(dev,
+					"DMA channel request failed with %d\n",
+					ret);
+			return ret;
+		}
+
+		/* DMA is optional: fall back to IRQ mode */
+		adc->dma_chan = NULL;
+		return 0;
+	}
+
+	adc->rx_buf = dma_alloc_coherent(adc->dma_chan->device->dev,
+					 STM32_DMA_BUFFER_SIZE,
+					 &adc->rx_dma_buf, GFP_KERNEL);
+	if (!adc->rx_buf) {
+		ret = -ENOMEM;
+		goto err_release;
+	}
+
+	/* Configure DMA channel to read data register */
+	memset(&config, 0, sizeof(config));
+	config.src_addr = (dma_addr_t)adc->common->phys_base;
+	config.src_addr += adc->offset + adc->cfg->regs->dr;
+	config.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
+
+	ret = dmaengine_slave_config(adc->dma_chan, &config);
+	if (ret)
+		goto err_free;
+
+	return 0;
+
+err_free:
+	dma_free_coherent(adc->dma_chan->device->dev, STM32_DMA_BUFFER_SIZE,
+			  adc->rx_buf, adc->rx_dma_buf);
+err_release:
+	dma_release_channel(adc->dma_chan);
+
+	return ret;
+}
+
+static int stm32_adc_probe(struct platform_device *pdev)
+{
+	struct iio_dev *indio_dev;
+	struct device *dev = &pdev->dev;
+	irqreturn_t (*handler)(int irq, void *p) = NULL;
+	struct stm32_adc *adc;
+	int ret;
+
+	if (!pdev->dev.of_node)
+		return -ENODEV;
+
+	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	adc = iio_priv(indio_dev);
+	adc->common = dev_get_drvdata(pdev->dev.parent);
+	spin_lock_init(&adc->lock);
+	init_completion(&adc->completion);
+	adc->cfg = (const struct stm32_adc_cfg *)
+		of_match_device(dev->driver->of_match_table, dev)->data;
+
+	indio_dev->name = dev_name(&pdev->dev);
+	indio_dev->dev.parent = &pdev->dev;
+	indio_dev->dev.of_node = pdev->dev.of_node;
+	indio_dev->info = &stm32_adc_iio_info;
+	indio_dev->modes = INDIO_DIRECT_MODE | INDIO_HARDWARE_TRIGGERED;
+
+	platform_set_drvdata(pdev, adc);
+
+	ret = of_property_read_u32(pdev->dev.of_node, "reg", &adc->offset);
+	if (ret != 0) {
+		dev_err(&pdev->dev, "missing reg property\n");
+		return -EINVAL;
+	}
+
+	adc->irq = platform_get_irq(pdev, 0);
+	if (adc->irq < 0) {
+		dev_err(&pdev->dev, "failed to get irq\n");
+		return adc->irq;
+	}
+
+	ret = devm_request_irq(&pdev->dev, adc->irq, stm32_adc_isr,
+			       0, pdev->name, adc);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to request IRQ\n");
+		return ret;
+	}
+
+	adc->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(adc->clk)) {
+		ret = PTR_ERR(adc->clk);
+		if (ret == -ENOENT && !adc->cfg->clk_required) {
+			adc->clk = NULL;
+		} else {
+			dev_err(&pdev->dev, "Can't get clock\n");
+			return ret;
+		}
+	}
+
+	if (adc->clk) {
+		ret = clk_prepare_enable(adc->clk);
+		if (ret < 0) {
+			dev_err(&pdev->dev, "clk enable failed\n");
+			return ret;
+		}
+	}
+
+	ret = stm32_adc_of_get_resolution(indio_dev);
+	if (ret < 0)
+		goto err_clk_disable;
+	stm32_adc_set_res(adc);
+
+	if (adc->cfg->selfcalib) {
+		ret = adc->cfg->selfcalib(adc);
+		if (ret)
+			goto err_clk_disable;
+	}
+
+	ret = stm32_adc_chan_of_init(indio_dev);
+	if (ret < 0)
+		goto err_clk_disable;
+
+	ret = stm32_adc_dma_request(dev, indio_dev);
+	if (ret < 0)
+		goto err_clk_disable;
+
+	if (!adc->dma_chan)
+		handler = &stm32_adc_trigger_handler;
+
+	ret = iio_triggered_buffer_setup(indio_dev,
+					 &iio_pollfunc_store_time, handler,
+					 &stm32_adc_buffer_setup_ops);
+	if (ret) {
+		dev_err(&pdev->dev, "buffer setup failed\n");
+		goto err_dma_disable;
+	}
+
+	ret = iio_device_register(indio_dev);
+	if (ret) {
+		dev_err(&pdev->dev, "iio dev register failed\n");
+		goto err_buffer_cleanup;
+	}
+
+	return 0;
+
+err_buffer_cleanup:
+	iio_triggered_buffer_cleanup(indio_dev);
+
+err_dma_disable:
+	if (adc->dma_chan) {
+		dma_free_coherent(adc->dma_chan->device->dev,
+				  STM32_DMA_BUFFER_SIZE,
+				  adc->rx_buf, adc->rx_dma_buf);
+		dma_release_channel(adc->dma_chan);
+	}
+err_clk_disable:
+	if (adc->clk)
+		clk_disable_unprepare(adc->clk);
+
+	return ret;
+}
+
+static int stm32_adc_remove(struct platform_device *pdev)
+{
+	struct stm32_adc *adc = platform_get_drvdata(pdev);
+	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
+
+	iio_device_unregister(indio_dev);
+	iio_triggered_buffer_cleanup(indio_dev);
+	if (adc->dma_chan) {
+		dma_free_coherent(adc->dma_chan->device->dev,
+				  STM32_DMA_BUFFER_SIZE,
+				  adc->rx_buf, adc->rx_dma_buf);
+		dma_release_channel(adc->dma_chan);
+	}
+	if (adc->clk)
+		clk_disable_unprepare(adc->clk);
+
+	return 0;
+}
+
+static const struct stm32_adc_cfg stm32f4_adc_cfg = {
+	.regs = &stm32f4_adc_regspec,
+	.adc_info = &stm32f4_adc_info,
+	.trigs = stm32f4_adc_trigs,
+	.clk_required = true,
+	.start_conv = stm32f4_adc_start_conv,
+	.stop_conv = stm32f4_adc_stop_conv,
+	.smp_cycles = stm32f4_adc_smp_cycles,
+};
+
+static const struct stm32_adc_cfg stm32h7_adc_cfg = {
+	.regs = &stm32h7_adc_regspec,
+	.adc_info = &stm32h7_adc_info,
+	.trigs = stm32h7_adc_trigs,
+	.selfcalib = stm32h7_adc_selfcalib,
+	.start_conv = stm32h7_adc_start_conv,
+	.stop_conv = stm32h7_adc_stop_conv,
+	.prepare = stm32h7_adc_prepare,
+	.unprepare = stm32h7_adc_unprepare,
+	.smp_cycles = stm32h7_adc_smp_cycles,
+};
+
+static const struct stm32_adc_cfg stm32mp1_adc_cfg = {
+	.regs = &stm32h7_adc_regspec,
+	.adc_info = &stm32h7_adc_info,
+	.trigs = stm32h7_adc_trigs,
+	.has_vregready = true,
+	.selfcalib = stm32h7_adc_selfcalib,
+	.start_conv = stm32h7_adc_start_conv,
+	.stop_conv = stm32h7_adc_stop_conv,
+	.prepare = stm32h7_adc_prepare,
+	.unprepare = stm32h7_adc_unprepare,
+	.smp_cycles = stm32h7_adc_smp_cycles,
+};
+
+static const struct of_device_id stm32_adc_of_match[] = {
+	{ .compatible = "st,stm32f4-adc", .data = (void *)&stm32f4_adc_cfg },
+	{ .compatible = "st,stm32h7-adc", .data = (void *)&stm32h7_adc_cfg },
+	{ .compatible = "st,stm32mp1-adc", .data = (void *)&stm32mp1_adc_cfg },
+	{},
+};
+MODULE_DEVICE_TABLE(of, stm32_adc_of_match);
+
+static struct platform_driver stm32_adc_driver = {
+	.probe = stm32_adc_probe,
+	.remove = stm32_adc_remove,
+	.driver = {
+		.name = "stm32-adc",
+		.of_match_table = stm32_adc_of_match,
+	},
+};
+module_platform_driver(stm32_adc_driver);
+
+MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
+MODULE_DESCRIPTION("STMicroelectronics STM32 ADC IIO driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:stm32-adc");