[PATCH v6 09/13] IIO: ADC: add STM32 DFSDM sigma delta ADC support

Arnaud Pouliquen
2017-12-01T17:40:16Z

Add DFSDM driver to handle sigma delta ADC.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen-qxv4g6HH51o@public.gmane.org>
---
drivers/iio/adc/Kconfig | 13 +
drivers/iio/adc/Makefile | 1 +
drivers/iio/adc/stm32-dfsdm-adc.c | 741 ++++++++++++++++++++++++++++++++++++++
3 files changed, 755 insertions(+)
create mode 100644 drivers/iio/adc/stm32-dfsdm-adc.c

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index b729ae0..98ca30b 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -677,6 +677,19 @@ config STM32_DFSDM_CORE
This driver can also be built as a module. If so, the module
will be called stm32-dfsdm-core.

+config STM32_DFSDM_ADC
+ tristate "STMicroelectronics STM32 dfsdm adc"
+ depends on (ARCH_STM32 && OF) || COMPILE_TEST
+ select STM32_DFSDM_CORE
+ select REGMAP_MMIO
+ select IIO_BUFFER_HW_CONSUMER
+ help
+ Select this option to support ADCSigma delta modulator for
+ STMicroelectronics STM32 digital filter for sigma delta converter.
+
+ This driver can also be built as a module. If so, the module
+ will be called stm32-dfsdm-adc.
+
config STX104
tristate "Apex Embedded Systems STX104 driver"
depends on PC104 && X86 && ISA_BUS_API
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index b52d0a0..c4f5d15 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -64,6 +64,7 @@ obj-$(CONFIG_SUN4I_GPADC) += sun4i-gpadc-iio.o
obj-$(CONFIG_STM32_ADC_CORE) += stm32-adc-core.o
obj-$(CONFIG_STM32_ADC) += stm32-adc.o
obj-$(CONFIG_STM32_DFSDM_CORE) += stm32-dfsdm-core.o
+obj-$(CONFIG_STM32_DFSDM_ADC) += stm32-dfsdm-adc.o
obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o
obj-$(CONFIG_TI_ADC0832) += ti-adc0832.o
obj-$(CONFIG_TI_ADC084S021) += ti-adc084s021.o
diff --git a/drivers/iio/adc/stm32-dfsdm-adc.c b/drivers/iio/adc/stm32-dfsdm-adc.c
new file mode 100644
index 0000000..f9419ab
--- /dev/null
+++ b/drivers/iio/adc/stm32-dfsdm-adc.c
@@ -0,0 +1,741 @@
+/*
+ * This file is the ADC part of the STM32 DFSDM driver
+ *
+ * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
+ * Author: Arnaud Pouliquen <arnaud.pouliquen-qxv4g6HH51o@public.gmane.org>.
+ *
+ * License type: GPL V2.0.
+ *
+ * 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 <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/hw-consumer.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+#include "stm32-dfsdm.h"
+
+/* Conversion timeout */
+#define DFSDM_TIMEOUT_US 100000
+#define DFSDM_TIMEOUT (msecs_to_jiffies(DFSDM_TIMEOUT_US / 1000))
+
+/* Oversampling attribute default */
+#define DFSDM_DEFAULT_OVERSAMPLING 100
+
+/* Oversampling max values */
+#define DFSDM_MAX_INT_OVERSAMPLING 256
+#define DFSDM_MAX_FL_OVERSAMPLING 1024
+
+/* Max sample resolutions */
+#define DFSDM_MAX_RES BIT(31)
+#define DFSDM_DATA_RES BIT(23)
+
+enum sd_converter_type {
+ DFSDM_AUDIO,
+ DFSDM_IIO,
+};
+
+struct stm32_dfsdm_dev_data {
+ int type;
+ int (*init)(struct iio_dev *indio_dev);
+ unsigned int num_channels;
+ const struct regmap_config *regmap_cfg;
+};
+
+struct stm32_dfsdm_adc {
+ struct stm32_dfsdm *dfsdm;
+ const struct stm32_dfsdm_dev_data *dev_data;
+ unsigned int fl_id;
+ unsigned int ch_id;
+
+ /* ADC specific */
+ unsigned int oversamp;
+ struct iio_hw_consumer *hwc;
+ struct completion completion;
+ u32 *buffer;
+
+};
+
+struct stm32_dfsdm_str2field {
+ const char *name;
+ unsigned int val;
+};
+
+/* DFSDM channel serial interface type */
+static const struct stm32_dfsdm_str2field stm32_dfsdm_chan_type[] = {
+ { "SPI_R", 0 }, /* SPI with data on rising edge */
+ { "SPI_F", 1 }, /* SPI with data on falling edge */
+ { "MANCH_R", 2 }, /* Manchester codec, rising edge = logic 0 */
+ { "MANCH_F", 3 }, /* Manchester codec, falling edge = logic 1 */
+ {},
+};
+
+/* DFSDM channel clock source */
+static const struct stm32_dfsdm_str2field stm32_dfsdm_chan_src[] = {
+ /* External SPI clock (CLKIN x) */
+ { "CLKIN", DFSDM_CHANNEL_SPI_CLOCK_EXTERNAL },
+ /* Internal SPI clock (CLKOUT) */
+ { "CLKOUT", DFSDM_CHANNEL_SPI_CLOCK_INTERNAL },
+ /* Internal SPI clock divided by 2 (falling edge) */
+ { "CLKOUT_F", DFSDM_CHANNEL_SPI_CLOCK_INTERNAL_DIV2_FALLING },
+ /* Internal SPI clock divided by 2 (falling edge) */
+ { "CLKOUT_R", DFSDM_CHANNEL_SPI_CLOCK_INTERNAL_DIV2_RISING },
+ {},
+};
+
+static int stm32_dfsdm_str2val(const char *str,
+ const struct stm32_dfsdm_str2field *list)
+{
+ const struct stm32_dfsdm_str2field *p = list;
+
+ for (p = list; p && p->name; p++)
+ if (!strcmp(p->name, str))
+ return p->val;
+
+ return -EINVAL;
+}
+
+static int stm32_dfsdm_set_osrs(struct stm32_dfsdm_filter *fl,
+ unsigned int fast, unsigned int oversamp)
+{
+ unsigned int i, d, fosr, iosr;
+ u64 res;
+ s64 delta;
+ unsigned int m = 1; /* multiplication factor */
+ unsigned int p = fl->ford; /* filter order (ford) */
+
+ pr_debug("%s: Requested oversampling: %d\n", __func__, oversamp);
+ /*
+ * This function tries to compute filter oversampling and integrator
+ * oversampling, base on oversampling ratio requested by user.
+ *
+ * Decimation d depends on the filter order and the oversampling ratios.
+ * ford: filter order
+ * fosr: filter over sampling ratio
+ * iosr: integrator over sampling ratio
+ */
+ if (fl->ford == DFSDM_FASTSINC_ORDER) {
+ m = 2;
+ p = 2;
+ }
+
+ /*
+ * Look for filter and integrator oversampling ratios which allows
+ * to reach 24 bits data output resolution.
+ * Leave as soon as if exact resolution if reached.
+ * Otherwise the higher resolution below 32 bits is kept.
+ */
+ for (fosr = 1; fosr <= DFSDM_MAX_FL_OVERSAMPLING; fosr++) {
+ for (iosr = 1; iosr <= DFSDM_MAX_INT_OVERSAMPLING; iosr++) {
+ if (fast)
+ d = fosr * iosr;
+ else if (fl->ford == DFSDM_FASTSINC_ORDER)
+ d = fosr * (iosr + 3) + 2;
+ else
+ d = fosr * (iosr - 1 + p) + p;
+
+ if (d > oversamp)
+ break;
+ else if (d != oversamp)
+ continue;
+ /*
+ * Check resolution (limited to signed 32 bits)
+ * res <= 2^31
+ * Sincx filters:
+ * res = m * fosr^p x iosr (with m=1, p=ford)
+ * FastSinc filter
+ * res = m * fosr^p x iosr (with m=2, p=2)
+ */
+ res = fosr;
+ for (i = p - 1; i > 0; i--) {
+ res = res * (u64)fosr;
+ if (res > DFSDM_MAX_RES)
+ break;
+ }
+ if (res > DFSDM_MAX_RES)
+ continue;
+ res = res * (u64)m * (u64)iosr;
+ if (res > DFSDM_MAX_RES)
+ continue;
+
+ delta = res - DFSDM_DATA_RES;
+
+ if (res >= fl->res) {
+ fl->res = res;
+ fl->fosr = fosr;
+ fl->iosr = iosr;
+ fl->fast = fast;
+ pr_debug("%s: fosr = %d, iosr = %d\n",
+ __func__, fl->fosr, fl->iosr);
+ }
+
+ if (!delta)
+ return 0;
+ }
+ }
+
+ if (!fl->fosr)
+ return -EINVAL;
+
+ return 0;
+}
+
+static int stm32_dfsdm_start_channel(struct stm32_dfsdm *dfsdm,
+ unsigned int ch_id)
+{
+ return regmap_update_bits(dfsdm->regmap, DFSDM_CHCFGR1(ch_id),
+ DFSDM_CHCFGR1_CHEN_MASK,
+ DFSDM_CHCFGR1_CHEN(1));
+}
+
+static void stm32_dfsdm_stop_channel(struct stm32_dfsdm *dfsdm,
+ unsigned int ch_id)
+{
+ regmap_update_bits(dfsdm->regmap, DFSDM_CHCFGR1(ch_id),
+ DFSDM_CHCFGR1_CHEN_MASK, DFSDM_CHCFGR1_CHEN(0));
+}
+
+static int stm32_dfsdm_chan_configure(struct stm32_dfsdm *dfsdm,
+ struct stm32_dfsdm_channel *ch)
+{
+ unsigned int id = ch->id;
+ struct regmap *regmap = dfsdm->regmap;
+ int ret;
+
+ ret = regmap_update_bits(regmap, DFSDM_CHCFGR1(id),
+ DFSDM_CHCFGR1_SITP_MASK,
+ DFSDM_CHCFGR1_SITP(ch->type));
+ if (ret < 0)
+ return ret;
+ ret = regmap_update_bits(regmap, DFSDM_CHCFGR1(id),
+ DFSDM_CHCFGR1_SPICKSEL_MASK,
+ DFSDM_CHCFGR1_SPICKSEL(ch->src));
+ if (ret < 0)
+ return ret;
+ return regmap_update_bits(regmap, DFSDM_CHCFGR1(id),
+ DFSDM_CHCFGR1_CHINSEL_MASK,
+ DFSDM_CHCFGR1_CHINSEL(ch->alt_si));
+}
+
+static int stm32_dfsdm_start_filter(struct stm32_dfsdm *dfsdm,
+ unsigned int fl_id)
+{
+ int ret;
+
+ /* Enable filter */
+ ret = regmap_update_bits(dfsdm->regmap, DFSDM_CR1(fl_id),
+ DFSDM_CR1_DFEN_MASK, DFSDM_CR1_DFEN(1));
+ if (ret < 0)
+ return ret;
+
+ /* Start conversion */
+ return regmap_update_bits(dfsdm->regmap, DFSDM_CR1(fl_id),
+ DFSDM_CR1_RSWSTART_MASK,
+ DFSDM_CR1_RSWSTART(1));
+}
+
+void stm32_dfsdm_stop_filter(struct stm32_dfsdm *dfsdm, unsigned int fl_id)
+{
+ /* Disable conversion */
+ regmap_update_bits(dfsdm->regmap, DFSDM_CR1(fl_id),
+ DFSDM_CR1_DFEN_MASK, DFSDM_CR1_DFEN(0));
+}
+
+static int stm32_dfsdm_filter_configure(struct stm32_dfsdm *dfsdm,
+ unsigned int fl_id, unsigned int ch_id)
+{
+ struct regmap *regmap = dfsdm->regmap;
+ struct stm32_dfsdm_filter *fl = &dfsdm->fl_list[fl_id];
+ int ret;
+
+ /* Average integrator oversampling */
+ ret = regmap_update_bits(regmap, DFSDM_FCR(fl_id), DFSDM_FCR_IOSR_MASK,
+ DFSDM_FCR_IOSR(fl->iosr - 1));
+ if (ret)
+ return ret;
+
+ /* Filter order and Oversampling */
+ ret = regmap_update_bits(regmap, DFSDM_FCR(fl_id), DFSDM_FCR_FOSR_MASK,
+ DFSDM_FCR_FOSR(fl->fosr - 1));
+ if (ret)
+ return ret;
+
+ ret = regmap_update_bits(regmap, DFSDM_FCR(fl_id), DFSDM_FCR_FORD_MASK,
+ DFSDM_FCR_FORD(fl->ford));
+ if (ret)
+ return ret;
+
+ /* No scan mode supported for the moment */
+ ret = regmap_update_bits(regmap, DFSDM_CR1(fl_id), DFSDM_CR1_RCH_MASK,
+ DFSDM_CR1_RCH(ch_id));
+ if (ret)
+ return ret;
+
+ return regmap_update_bits(regmap, DFSDM_CR1(fl_id),
+ DFSDM_CR1_RSYNC_MASK,
+ DFSDM_CR1_RSYNC(fl->sync_mode));
+}
+
+int stm32_dfsdm_channel_parse_of(struct stm32_dfsdm *dfsdm,
+ struct iio_dev *indio_dev,
+ struct iio_chan_spec *ch)
+{
+ struct stm32_dfsdm_channel *df_ch;
+ const char *of_str;
+ int chan_idx = ch->scan_index;
+ int ret, val;
+
+ ret = of_property_read_u32_index(indio_dev->dev.of_node,
+ "st,adc-channels", chan_idx,
+ &ch->channel);
+ if (ret < 0) {
+ dev_err(&indio_dev->dev,
+ " Error parsing 'st,adc-channels' for idx %d\n",
+ chan_idx);
+ return ret;
+ }
+ if (ch->channel >= dfsdm->num_chs) {
+ dev_err(&indio_dev->dev,
+ " Error bad channel number %d (max = %d)\n",
+ ch->channel, dfsdm->num_chs);
+ return -EINVAL;
+ }
+
+ ret = of_property_read_string_index(indio_dev->dev.of_node,
+ "st,adc-channel-names", chan_idx,
+ &ch->datasheet_name);
+ if (ret < 0) {
+ dev_err(&indio_dev->dev,
+ " Error parsing 'st,adc-channel-names' for idx %d\n",
+ chan_idx);
+ return ret;
+ }
+
+ df_ch = &dfsdm->ch_list[ch->channel];
+ df_ch->id = ch->channel;
+
+ ret = of_property_read_string_index(indio_dev->dev.of_node,
+ "st,adc-channel-types", chan_idx,
+ &of_str);
+ if (!ret) {
+ val = stm32_dfsdm_str2val(of_str, stm32_dfsdm_chan_type);
+ if (val < 0)
+ return val;
+ } else {
+ val = 0;
+ }
+ df_ch->type = val;
+
+ ret = of_property_read_string_index(indio_dev->dev.of_node,
+ "st,adc-channel-clk-src", chan_idx,
+ &of_str);
+ if (!ret) {
+ val = stm32_dfsdm_str2val(of_str, stm32_dfsdm_chan_src);
+ if (val < 0)
+ return val;
+ } else {
+ val = 0;
+ }
+ df_ch->src = val;
+
+ ret = of_property_read_u32_index(indio_dev->dev.of_node,
+ "st,adc-alt-channel", chan_idx,
+ &df_ch->alt_si);
+ if (ret < 0)
+ df_ch->alt_si = 0;
+
+ return 0;
+}
+
+static int stm32_dfsdm_start_conv(struct stm32_dfsdm_adc *adc, bool dma)
+{
+ struct regmap *regmap = adc->dfsdm->regmap;
+ int ret;
+
+ ret = stm32_dfsdm_start_channel(adc->dfsdm, adc->ch_id);
+ if (ret < 0)
+ return ret;
+
+ ret = stm32_dfsdm_filter_configure(adc->dfsdm, adc->fl_id,
+ adc->ch_id);
+ if (ret < 0)
+ goto stop_channels;
+
+ ret = stm32_dfsdm_start_filter(adc->dfsdm, adc->fl_id);
+ if (ret < 0)
+ goto stop_channels;
+
+ return 0;
+
+stop_channels:
+ regmap_update_bits(regmap, DFSDM_CR1(adc->fl_id),
+ DFSDM_CR1_RDMAEN_MASK, 0);
+
+ regmap_update_bits(regmap, DFSDM_CR1(adc->fl_id),
+ DFSDM_CR1_RCONT_MASK, 0);
+ stm32_dfsdm_stop_channel(adc->dfsdm, adc->fl_id);
+
+ return ret;
+}
+
+static void stm32_dfsdm_stop_conv(struct stm32_dfsdm_adc *adc)
+{
+ struct regmap *regmap = adc->dfsdm->regmap;
+
+ stm32_dfsdm_stop_filter(adc->dfsdm, adc->fl_id);
+
+ /* Clean conversion options */
+ regmap_update_bits(regmap, DFSDM_CR1(adc->fl_id),
+ DFSDM_CR1_RDMAEN_MASK, 0);
+
+ regmap_update_bits(regmap, DFSDM_CR1(adc->fl_id),
+ DFSDM_CR1_RCONT_MASK, 0);
+
+ stm32_dfsdm_stop_channel(adc->dfsdm, adc->ch_id);
+}
+
+static int stm32_dfsdm_single_conv(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan, int *res)
+{
+ struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
+ long timeout;
+ int ret;
+
+ reinit_completion(&adc->completion);
+
+ adc->buffer = res;
+
+ ret = stm32_dfsdm_start_dfsdm(adc->dfsdm);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_update_bits(adc->dfsdm->regmap, DFSDM_CR2(adc->fl_id),
+ DFSDM_CR2_REOCIE_MASK, DFSDM_CR2_REOCIE(1));
+ if (ret < 0)
+ goto stop_dfsdm;
+
+ ret = stm32_dfsdm_start_conv(adc, false);
+ if (ret < 0) {
+ regmap_update_bits(adc->dfsdm->regmap, DFSDM_CR2(adc->fl_id),
+ DFSDM_CR2_REOCIE_MASK, DFSDM_CR2_REOCIE(0));
+ goto stop_dfsdm;
+ }
+
+ timeout = wait_for_completion_interruptible_timeout(&adc->completion,
+ DFSDM_TIMEOUT);
+
+ /* Mask IRQ for regular conversion achievement*/
+ regmap_update_bits(adc->dfsdm->regmap, DFSDM_CR2(adc->fl_id),
+ DFSDM_CR2_REOCIE_MASK, DFSDM_CR2_REOCIE(0));
+
+ if (timeout == 0)
+ ret = -ETIMEDOUT;
+ else if (timeout < 0)
+ ret = timeout;
+ else
+ ret = IIO_VAL_INT;
+
+ stm32_dfsdm_stop_conv(adc);
+
+stop_dfsdm:
+ stm32_dfsdm_stop_dfsdm(adc->dfsdm);
+
+ return ret;
+}
+
+static int stm32_dfsdm_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int val, int val2, long mask)
+{
+ struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
+ struct stm32_dfsdm_filter *fl = &adc->dfsdm->fl_list[adc->fl_id];
+ int ret = -EINVAL;
+
+ if (mask == IIO_CHAN_INFO_OVERSAMPLING_RATIO) {
+ ret = stm32_dfsdm_set_osrs(fl, 0, val);
+ if (!ret)
+ adc->oversamp = val;
+ }
+
+ return ret;
+}
+
+static int stm32_dfsdm_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan, int *val,
+ int *val2, long mask)
+{
+ struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
+ int ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ ret = iio_hw_consumer_enable(adc->hwc);
+ if (ret < 0) {
+ dev_err(&indio_dev->dev,
+ "%s: IIO enable failed (channel %d)\n",
+ __func__, chan->channel);
+ return ret;
+ }
+ ret = stm32_dfsdm_single_conv(indio_dev, chan, val);
+ iio_hw_consumer_disable(adc->hwc);
+ if (ret < 0) {
+ dev_err(&indio_dev->dev,
+ "%s: Conversion failed (channel %d)\n",
+ __func__, chan->channel);
+ return ret;
+ }
+ return IIO_VAL_INT;
+
+ case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+ *val = adc->oversamp;
+
+ return IIO_VAL_INT;
+ }
+
+ return -EINVAL;
+}
+
+static const struct iio_info stm32_dfsdm_info_adc = {
+ .read_raw = stm32_dfsdm_read_raw,
+ .write_raw = stm32_dfsdm_write_raw,
+};
+
+static irqreturn_t stm32_dfsdm_irq(int irq, void *arg)
+{
+ struct stm32_dfsdm_adc *adc = arg;
+ struct iio_dev *indio_dev = iio_priv_to_dev(adc);
+ struct regmap *regmap = adc->dfsdm->regmap;
+ unsigned int status, int_en;
+
+ regmap_read(regmap, DFSDM_ISR(adc->fl_id), &status);
+ regmap_read(regmap, DFSDM_CR2(adc->fl_id), &int_en);
+
+ if (status & DFSDM_ISR_REOCF_MASK) {
+ /* Read the data register clean the IRQ status */
+ regmap_read(regmap, DFSDM_RDATAR(adc->fl_id), adc->buffer);
+ complete(&adc->completion);
+ }
+
+ if (status & DFSDM_ISR_ROVRF_MASK) {
+ if (int_en & DFSDM_CR2_ROVRIE_MASK)
+ dev_warn(&indio_dev->dev, "Overrun detected\n");
+ regmap_update_bits(regmap, DFSDM_ICR(adc->fl_id),
+ DFSDM_ICR_CLRROVRF_MASK,
+ DFSDM_ICR_CLRROVRF_MASK);
+ }
+
+ return IRQ_HANDLED;
+}
+
+static int stm32_dfsdm_adc_chan_init_one(struct iio_dev *indio_dev,
+ struct iio_chan_spec *ch)
+{
+ struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
+ int ret;
+
+ ret = stm32_dfsdm_channel_parse_of(adc->dfsdm, indio_dev, ch);
+ if (ret < 0)
+ return ret;
+
+ ch->type = IIO_VOLTAGE;
+ ch->indexed = 1;
+
+ /*
+ * IIO_CHAN_INFO_RAW: used to compute regular conversion
+ * IIO_CHAN_INFO_OVERSAMPLING_RATIO: used to set oversampling
+ */
+ ch->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
+ ch->info_mask_shared_by_all = BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO);
+
+ ch->scan_type.sign = 'u';
+ ch->scan_type.realbits = 24;
+ ch->scan_type.storagebits = 32;
+ adc->ch_id = ch->channel;
+
+ return stm32_dfsdm_chan_configure(adc->dfsdm,
+ &adc->dfsdm->ch_list[ch->channel]);
+}
+
+static int stm32_dfsdm_adc_init(struct iio_dev *indio_dev)
+{
+ struct iio_chan_spec *ch;
+ struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
+ int num_ch;
+ int ret, chan_idx;
+
+ adc->oversamp = DFSDM_DEFAULT_OVERSAMPLING;
+ ret = stm32_dfsdm_set_osrs(&adc->dfsdm->fl_list[adc->fl_id], 0,
+ adc->oversamp);
+ if (ret < 0)
+ return ret;
+
+ num_ch = of_property_count_u32_elems(indio_dev->dev.of_node,
+ "st,adc-channels");
+ if (num_ch < 0 || num_ch > adc->dfsdm->num_chs) {
+ dev_err(&indio_dev->dev, "Bad st,adc-channels\n");
+ return num_ch < 0 ? num_ch : -EINVAL;
+ }
+
+ /* Bind to SD modulator IIO device */
+ adc->hwc = devm_iio_hw_consumer_alloc(&indio_dev->dev);
+ if (IS_ERR(adc->hwc))
+ return -EPROBE_DEFER;
+
+ ch = devm_kcalloc(&indio_dev->dev, num_ch, sizeof(*ch),
+ GFP_KERNEL);
+ if (!ch)
+ return -ENOMEM;
+
+ for (chan_idx = 0; chan_idx < num_ch; chan_idx++) {
+ ch->scan_index = chan_idx;
+ ret = stm32_dfsdm_adc_chan_init_one(indio_dev, ch);
+ if (ret < 0) {
+ dev_err(&indio_dev->dev, "Channels init failed\n");
+ return ret;
+ }
+ }
+
+ indio_dev->num_channels = num_ch;
+ indio_dev->channels = ch;
+
+ init_completion(&adc->completion);
+
+ return 0;
+}
+
+static const struct stm32_dfsdm_dev_data stm32h7_dfsdm_adc_data = {
+ .type = DFSDM_IIO,
+ .init = stm32_dfsdm_adc_init,
+};
+
+static const struct of_device_id stm32_dfsdm_adc_match[] = {
+ { .compatible = "st,stm32-dfsdm-adc",
+ .data = &stm32h7_dfsdm_adc_data,
+ },
+ {}
+};
+
+static int stm32_dfsdm_adc_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct stm32_dfsdm_adc *adc;
+ struct device_node *np = dev->of_node;
+ const struct stm32_dfsdm_dev_data *dev_data;
+ struct iio_dev *iio;
+ const struct of_device_id *of_id;
+ char *name;
+ int ret, irq, val;
+
+ of_id = of_match_node(stm32_dfsdm_adc_match, np);
+ if (!of_id->data) {
+ dev_err(&pdev->dev, "Data associated to device is missing\n");
+ return -EINVAL;
+ }
+
+ dev_data = (const struct stm32_dfsdm_dev_data *)of_id->data;
+
+ iio = devm_iio_device_alloc(dev, sizeof(*adc));
+ if (IS_ERR(iio)) {
+ dev_err(dev, "%s: Failed to allocate IIO\n", __func__);
+ return PTR_ERR(iio);
+ }
+
+ adc = iio_priv(iio);
+ if (IS_ERR(adc)) {
+ dev_err(dev, "%s: Failed to allocate ADC\n", __func__);
+ return PTR_ERR(adc);
+ }
+ adc->dfsdm = dev_get_drvdata(dev->parent);
+
+ iio->dev.parent = dev;
+ iio->dev.of_node = np;
+ iio->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_SOFTWARE;
+
+ platform_set_drvdata(pdev, adc);
+
+ ret = of_property_read_u32(dev->of_node, "reg", &adc->fl_id);
+ if (ret != 0) {
+ dev_err(dev, "Missing reg property\n");
+ return -EINVAL;
+ }
+
+ name = devm_kzalloc(dev, sizeof("dfsdm-adc0"), GFP_KERNEL);
+ if (!name)
+ return -ENOMEM;
+ iio->info = &stm32_dfsdm_info_adc;
+ snprintf(name, sizeof("dfsdm-adc0"), "dfsdm-adc%d", adc->fl_id);
+ iio->name = name;
+
+ /*
+ * In a first step IRQs generated for channels are not treated.
+ * So IRQ associated to filter instance 0 is dedicated to the Filter 0.
+ */
+ irq = platform_get_irq(pdev, 0);
+ ret = devm_request_irq(dev, irq, stm32_dfsdm_irq,
+ 0, pdev->name, adc);
+ if (ret < 0) {
+ dev_err(dev, "Failed to request IRQ\n");
+ return ret;
+ }
+
+ ret = of_property_read_u32(dev->of_node, "st,filter-order", &val);
+ if (ret < 0) {
+ dev_err(dev, "Failed to set filter order\n");
+ return ret;
+ }
+
+ adc->dfsdm->fl_list[adc->fl_id].ford = val;
+
+ ret = of_property_read_u32(dev->of_node, "st,filter0-sync", &val);
+ if (!ret)
+ adc->dfsdm->fl_list[adc->fl_id].sync_mode = val;
+
+ adc->dev_data = dev_data;
+ ret = dev_data->init(iio);
+ if (ret < 0)
+ return ret;
+
+ return iio_device_register(iio);
+}
+
+static int stm32_dfsdm_adc_remove(struct platform_device *pdev)
+{
+ struct stm32_dfsdm_adc *adc = platform_get_drvdata(pdev);
+ struct iio_dev *indio_dev = iio_priv_to_dev(adc);
+
+ iio_device_unregister(indio_dev);
+
+ return 0;
+}
+
+static struct platform_driver stm32_dfsdm_adc_driver = {
+ .driver = {
+ .name = "stm32-dfsdm-adc",
+ .of_match_table = stm32_dfsdm_adc_match,
+ },
+ .probe = stm32_dfsdm_adc_probe,
+ .remove = stm32_dfsdm_adc_remove,
+
+};
+module_platform_driver(stm32_dfsdm_adc_driver);
+
+MODULE_DESCRIPTION("STM32 sigma delta ADC");
+MODULE_AUTHOR("Arnaud Pouliquen <arnaud.pouliquen-qxv4g6HH51o@public.gmane.org>");
+MODULE_LICENSE("GPL v2");
--
2.7.4

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