/* * This file is part of STM32 ADC driver * * Copyright (C) 2016, STMicroelectronics - All Rights Reserved * Author: Fabrice Gasnier . * * License type: GPLv2 * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 as published by * the Free Software Foundation. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY * or FITNESS FOR A PARTICULAR PURPOSE. * See the GNU General Public License for more details. * * You should have received a copy of the GNU General Public License along with * this program. If not, see . */ #include #include #include #include #include #include #include #include #include #include #include #include #include "stm32-adc-core.h" /* STM32F4 - Registers for each ADC instance */ #define STM32F4_ADC_SR 0x00 #define STM32F4_ADC_CR1 0x04 #define STM32F4_ADC_CR2 0x08 #define STM32F4_ADC_SMPR1 0x0C #define STM32F4_ADC_SMPR2 0x10 #define STM32F4_ADC_HTR 0x24 #define STM32F4_ADC_LTR 0x28 #define STM32F4_ADC_SQR1 0x2C #define STM32F4_ADC_SQR2 0x30 #define STM32F4_ADC_SQR3 0x34 #define STM32F4_ADC_JSQR 0x38 #define STM32F4_ADC_JDR1 0x3C #define STM32F4_ADC_JDR2 0x40 #define STM32F4_ADC_JDR3 0x44 #define STM32F4_ADC_JDR4 0x48 #define STM32F4_ADC_DR 0x4C /* STM32F4_ADC_SR - bit fields */ #define STM32F4_STRT BIT(4) #define STM32F4_EOC BIT(1) /* STM32F4_ADC_CR1 - bit fields */ #define STM32F4_SCAN BIT(8) #define STM32F4_EOCIE BIT(5) /* 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) #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 * @offset: ADC instance register offset in ADC block * @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 */ struct stm32_adc { struct stm32_adc_common *common; u32 offset; 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; }; /** * struct stm32_adc_chan_spec - specification of stm32 adc channel * @type: IIO channel type * @channel: channel number (single ended) * @name: channel name (single ended) */ struct stm32_adc_chan_spec { enum iio_chan_type type; int channel; const char *name; }; /* Input definitions common for all STM32F4 instances */ static const struct stm32_adc_chan_spec stm32f4_adc123_channels[] = { { IIO_VOLTAGE, 0, "in0" }, { IIO_VOLTAGE, 1, "in1" }, { IIO_VOLTAGE, 2, "in2" }, { IIO_VOLTAGE, 3, "in3" }, { IIO_VOLTAGE, 4, "in4" }, { IIO_VOLTAGE, 5, "in5" }, { IIO_VOLTAGE, 6, "in6" }, { IIO_VOLTAGE, 7, "in7" }, { IIO_VOLTAGE, 8, "in8" }, { IIO_VOLTAGE, 9, "in9" }, { IIO_VOLTAGE, 10, "in10" }, { IIO_VOLTAGE, 11, "in11" }, { IIO_VOLTAGE, 12, "in12" }, { IIO_VOLTAGE, 13, "in13" }, { IIO_VOLTAGE, 14, "in14" }, { IIO_VOLTAGE, 15, "in15" }, }; /** * 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 * * 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); } 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, STM32F4_ADC_CR1, STM32F4_EOCIE); }; /** * 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, STM32F4_ADC_CR1, STM32F4_EOCIE); } /** * stm32_adc_start_conv() - Start conversions for regular channels. * @adc: stm32 adc instance */ static void stm32_adc_start_conv(struct stm32_adc *adc) { stm32_adc_set_bits(adc, STM32F4_ADC_CR1, STM32F4_SCAN); 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 stm32_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); } /** * 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 * @res: conversion result * * The function performs a single conversion on a given channel: * - 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); long timeout; u32 val; int ret; reinit_completion(&adc->completion); adc->bufi = 0; /* 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_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); stm32_adc_conv_irq_enable(adc); stm32_adc_start_conv(adc); 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; } stm32_adc_stop_conv(adc); stm32_adc_conv_irq_disable(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: *val = adc->common->vref_mv; *val2 = chan->scan_type.realbits; return IIO_VAL_FRACTIONAL_LOG2; 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); u32 status = stm32_adc_readl(adc, STM32F4_ADC_SR); if (status & STM32F4_EOC) { /* 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) { 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, .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, int scan_index) { chan->type = channel->type; chan->channel = channel->channel; chan->datasheet_name = channel->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); chan->scan_type.sign = 'u'; chan->scan_type.realbits = 12; chan->scan_type.storagebits = 16; } static int stm32_adc_chan_of_init(struct iio_dev *indio_dev) { struct device_node *node = indio_dev->dev.of_node; struct property *prop; const __be32 *cur; struct iio_chan_spec *channels; int scan_index = 0, num_channels; u32 val; num_channels = of_property_count_u32_elems(node, "st,adc-channels"); if (num_channels < 0 || num_channels >= ARRAY_SIZE(stm32f4_adc123_channels)) { dev_err(&indio_dev->dev, "Bad st,adc-channels?\n"); return num_channels < 0 ? num_channels : -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 >= ARRAY_SIZE(stm32f4_adc123_channels)) { dev_err(&indio_dev->dev, "Invalid channel %d\n", val); return -EINVAL; } stm32_adc_chan_init_one(indio_dev, &channels[scan_index], &stm32f4_adc123_channels[val], scan_index); scan_index++; } indio_dev->num_channels = scan_index; indio_dev->channels = channels; return 0; } static int stm32_adc_probe(struct platform_device *pdev) { struct iio_dev *indio_dev; 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); 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; 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)) { dev_err(&pdev->dev, "Can't get clock\n"); return PTR_ERR(adc->clk); } ret = clk_prepare_enable(adc->clk); if (ret < 0) { dev_err(&pdev->dev, "clk enable failed\n"); return ret; } ret = stm32_adc_chan_of_init(indio_dev); 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_buffer_cleanup; } return 0; err_buffer_cleanup: iio_triggered_buffer_cleanup(indio_dev); err_clk_disable: 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); clk_disable_unprepare(adc->clk); return 0; } static const struct of_device_id stm32_adc_of_match[] = { { .compatible = "st,stm32f4-adc" }, {}, }; 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 "); MODULE_DESCRIPTION("STMicroelectronics STM32 ADC IIO driver"); MODULE_LICENSE("GPL v2"); MODULE_ALIAS("platform:stm32-adc");