[RFC v2 7/7] IIO: ADC: add stm32 DFSDM support
Jonathan Cameron
jic23 at kernel.org
Sun Mar 5 02:55:02 PST 2017
On 27/02/17 10:09, Arnaud Pouliquen wrote:
> Hello Jonathan,
>
> Late answer... sorry for this.
>
> I will integrate your remark in V2.
> Please find my answers in-line
>
> Regards
> Arnaud
>
> On 02/19/2017 03:46 PM, Jonathan Cameron wrote:
>> On 13/02/17 16:38, Arnaud Pouliquen wrote:
>>> Add driver for stm32 DFSDM IP. This IP converts a sigma delta stream in
>>> n bit samples through a low pass filter and an integrator.
>>>
>>> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen at st.com>
>> I think this fits together rather nicely. As before, various comments that
>> are irrelevant to an RFC (I just couldn't stop myself ;) and a few more
>> relevant ones.
>>
>> So as far as I'm concerned: Looking forward to the full version!
>> (as long as Mark and others are happy of course)
>>
>> I definitely want to ultimately see buffered and dma support on the
>> ADC driver side of things as well but that can come later.
> Ok, I suppose that DMA in cyclic mode should also be required for some
> other IIO driver...
>>
>> Jonathan
>>> ---
>>> drivers/iio/adc/Kconfig | 13 +
>>> drivers/iio/adc/Makefile | 1 +
>>> drivers/iio/adc/stm32-dfsdm-adc.c | 483 +++++++++++++++++++++++++++++++++++++
>>> drivers/iio/adc/stm32-dfsdm-core.c | 273 +++++++++++++++++++++
>>> drivers/iio/adc/stm32-dfsdm.h | 141 +++++++++++
>>> 5 files changed, 911 insertions(+)
>>> create mode 100644 drivers/iio/adc/stm32-dfsdm-adc.c
>>> create mode 100644 drivers/iio/adc/stm32-dfsdm-core.c
>>> create mode 100644 drivers/iio/adc/stm32-dfsdm.h
>>>
>>> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
>>> index d4366ac..ab917b6 100644
>>> --- a/drivers/iio/adc/Kconfig
>>> +++ b/drivers/iio/adc/Kconfig
>>> @@ -452,6 +452,19 @@ config STM32_ADC
>>> This driver can also be built as a module. If so, the module
>>> will be called stm32-adc.
>>>
>>> +config STM32_DFSDM_ADC
>>> + tristate "STMicroelectronics STM32 dfsdm adc"
>>> + depends on (ARCH_STM32 && OF) || COMPILE_TEST
>>> + select REGMAP
>>> + select REGMAP_MMIO
>>> + select IIO_HW_CONSUMER
>>> + help
>>> + Select this option to enable the driver for STMicroelectronics
>>> + STM32 digital filter for sigma delta converter (ADC).
>>> +
>>> + This driver can also be built as a module. If so, the module
>>> + will be called stm32-adc-dfsdm-adc.
>>> +
>>> config STX104
>>> tristate "Apex Embedded Systems STX104 driver"
>>> depends on X86 && ISA_BUS_API
>>> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
>>> index bd67144..5bcad23 100644
>>> --- a/drivers/iio/adc/Makefile
>>> +++ b/drivers/iio/adc/Makefile
>>> @@ -43,6 +43,7 @@ obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o
>>> obj-$(CONFIG_STX104) += stx104.o
>>> obj-$(CONFIG_STM32_ADC_CORE) += stm32-adc-core.o
>>> obj-$(CONFIG_STM32_ADC) += stm32-adc.o
>>> +obj-$(CONFIG_STM32_DFSDM_ADC) += stm32-dfsdm-adc.o stm32-dfsdm-core.o
>>> obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o
>>> obj-$(CONFIG_TI_ADC0832) += ti-adc0832.o
>>> obj-$(CONFIG_TI_ADC12138) += ti-adc12138.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..8f9c3263
>>> --- /dev/null
>>> +++ b/drivers/iio/adc/stm32-dfsdm-adc.c
>>> @@ -0,0 +1,483 @@
>>> +/*
>>> + * This file is part of STM32 DFSDM ADC driver
>>> + *
>>> + * Copyright (C) 2016, STMicroelectronics - All Rights Reserved
>>> + * Author: Arnaud Pouliquen <arnaud.pouliquen at st.com>.
>>> + *
>>> + * 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 <http://www.gnu.org/licenses/>.
>>> + */
>>> +
>>> +#include <linux/interrupt.h>
>>> +#include <linux/io.h>
>>> +#include <linux/module.h>
>>> +#include <linux/of.h>
>>> +#include <linux/platform_device.h>
>>> +#include <linux/slab.h>
>>> +
>>> +#include <linux/iio/hw_consumer.h>
>>> +#include <linux/iio/iio.h>
>>> +#include <linux/iio/sysfs.h>
>>> +
>>> +#include <sound/stm32-adfsdm.h>
>>> +
>>> +#include "stm32-dfsdm.h"
>>> +
>>> +enum stm32_dfsdm_mode {
>>> + DFSDM_ADC, /* ADC mode, access through IIO ABI */
>>> + DFSDM_AUDIO /* Audio mode, access through ASoC ABI */
>>> +};
>>> +
>>> +struct stm32_dfsdm_adc {
>>> + struct stm32_dfsdm *common;
>>> +
>>> + unsigned int fl_id;
>>> + unsigned int oversamp;
>>> + unsigned int clk_freq;
>>> +
>>> + enum stm32_dfsdm_mode mode;
>>> + struct platform_device *audio_pdev;
>>> +
>>> + void (*overrun_cb)(void *context);
>>> + void *cb_context;
>>> +
>>> + /* Hardware consumer structure for Front End iio */
>> IIO
>>> + struct iio_hw_consumer *hwc;
>>> +};
>>> +
>>> +static const enum stm32_dfsdm_mode stm32_dfsdm_data_adc = DFSDM_ADC;
>>> +static const enum stm32_dfsdm_mode stm32_dfsdm_data_audio = DFSDM_AUDIO;
>>> +
>>> +struct stm32_dfsdm_adc_devdata {
>>> + enum stm32_dfsdm_mode mode;
>>> + const struct iio_info *info;
>>> +};
>>> +
>>> +static int stm32_dfsdm_set_osrs(struct stm32_dfsdm_adc *adc, bool fast,
>>> + unsigned int oversamp)
>>> +{
>>> + /*
>>> + * TODO
>>> + * This function tries to compute filter oversampling and integrator
>>> + * oversampling, base on oversampling ratio requested by user.
>>> + */
>>> +
>>> + return 0;
>>> +};
>>> +
>>> +static int stm32_dfsdm_single_conv(struct iio_dev *indio_dev,
>>> + const struct iio_chan_spec *chan, int *res)
>>> +{
>>> + /* TODO: Perform conversion instead of sending fake value */
>>> + dev_dbg(&indio_dev->dev, "%s\n", __func__);
>> :( Definitely an RFC
>>> +
>>> + *res = chan->channel + 0xFFFF00;
>>> + return 0;
>>> +}
>>> +
>>> +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);
>>> + int ret;
>>> +
>>> + switch (mask) {
>>> + case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
>>> + ret = stm32_dfsdm_set_osrs(adc, 0, val);
>>> + if (!ret)
>>> + adc->oversamp = val;
>> If no reason to carry on,(i.e. nothing to unwind) return directly from within
>> the switch statement.
>>> + break;
>>> + case IIO_CHAN_INFO_SAMP_FREQ:
>>> + if (adc->mode == DFSDM_AUDIO)
>>> + ret = stm32_dfsdm_set_osrs(adc, 0, val);
>>> + else
>>> + ret = -EINVAL;
>>> + break;
>>> +
>>> + default:
>>> + ret = -EINVAL;
>>> + }
>>> +
>>> + 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;
>>> +
>>> + dev_dbg(&indio_dev->dev, "%s\n", __func__);
>>> + switch (mask) {
>>> + case IIO_CHAN_INFO_RAW:
>>> + if (adc->hwc) {
>>> + 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;
>>> + }
>> Not an error if hwc not available?
> ASoC framework requests to handle a codec driver. So in case of PDM
> usecase, no IIO SD modulator device is used, instead an ASoC generic
> dmic-codec device is probed. In other words the link between the DFSDM
> and the external SD-modulator has to be done in ASOC for PDMs and in
> IIO for ADCs.
Fair enough. Please add a comment in the code to that effect so others
in future know what is going on (and for when I inevitably forget!)
>
>>> + }
>>> + ret = stm32_dfsdm_single_conv(indio_dev, chan, val);
>>> + if (ret < 0) {
>>> + dev_err(&indio_dev->dev,
>>> + "%s: conversion failed (channel %d)\n",
>>> + __func__, chan->channel);
>>> + return ret;
>>> + }
>>> +
>>> + if (adc->hwc)
>>> + iio_hw_consumer_disable(adc->hwc);
>>> +
>>> + return IIO_VAL_INT;
>>> +
>>> + case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
>>> + *val = adc->oversamp;
>>> +
>>> + return IIO_VAL_INT;
>>> +
>>> + case IIO_CHAN_INFO_SAMP_FREQ:
>>> + *val = DIV_ROUND_CLOSEST(adc->clk_freq, 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,
>>> + .driver_module = THIS_MODULE,
>>> +};
>>> +
>>> +static const struct iio_info stm32_dfsdm_info_audio = {
>>> + .read_raw = stm32_dfsdm_read_raw,
>>> + .write_raw = stm32_dfsdm_write_raw,
>>> + .driver_module = THIS_MODULE,
>>> +};
>> Hohum. These two are the same, why two copies? Mind you for the audio
>> you can't write or read anything so you could drop the callbacks.
> yes to rework.
>>> +
>>> +const struct stm32_dfsdm_adc_devdata stm32_dfsdm_devdata_adc = {
>>> + .mode = DFSDM_ADC,
>>> + .info = &stm32_dfsdm_info_adc,
>>> +};
>>> +
>>> +const struct stm32_dfsdm_adc_devdata stm32_dfsdm_devdata_audio = {
>>> + .mode = DFSDM_AUDIO,
>>> + .info = &stm32_dfsdm_info_audio,
>>> +};
>>> +
>>> +static irqreturn_t stm32_dfsdm_irq(int irq, void *arg)
>>> +{
>>> + /* TODO */
>>> + return IRQ_HANDLED;
>>> +}
>>> +
>>> +static void stm32_dfsdm_set_sysclk(struct stm32_dfsdm_adc *adc,
>>> + unsigned int freq)
>>> +{
>>> + struct iio_dev *iio = iio_priv_to_dev(adc);
>>> +
>>> + dev_dbg(&iio->dev, "%s:\n", __func__);
>>> +
>>> + adc->clk_freq = freq;
>>> +};
>>> +
>>> + /* Set expected audio sampling rate */
>>> +static int stm32_dfsdm_set_hwparam(struct stm32_dfsdm_adc *adc,
>>> + struct stm32_dfsdm_hw_param *params)
>>> +{
>>> + struct iio_dev *iio = iio_priv_to_dev(adc);
>>> +
>>> + dev_dbg(&iio->dev, "%s for rate %d\n", __func__, params->rate);
>>> +
>>> + return stm32_dfsdm_set_osrs(adc, 0, params->rate);
>>> +};
>>> +
>>> + /* Called when ASoC starts an audio stream setup. */
>>> +static int stm32_dfsdm_audio_startup(struct stm32_dfsdm_adc *adc)
>>> +{
>>> + struct iio_dev *iio = iio_priv_to_dev(adc);
>>> +
>>> + dev_dbg(&iio->dev, "%s\n", __func__);
>>> +
>>> + return 0;
>>> +};
>>> +
>>> + /* Shuts down the audio stream. */
>> Odd indenting.
>>> +static void stm32_dfsdm_audio_shutdown(struct stm32_dfsdm_adc *adc)
>>> +{
>>> + struct iio_dev *iio = iio_priv_to_dev(adc);
>>> +
>>> + dev_dbg(&iio->dev, "%s\n", __func__);
>>> +};
>>> +
>>> + /*
>>> + * Provides DMA source physicla addr to allow ALsa to handle DMA
>>> + * transfers.
>> physical - please run a spell checker over the comments.
>>> + */
>>> +static dma_addr_t stm32_dfsdm_get_dma_source(struct stm32_dfsdm_adc *adc)
>>> +{
>>> + struct iio_dev *iio = iio_priv_to_dev(adc);
>>> +
>>> + dev_dbg(&iio->dev, "%s\n", __func__);
>>> +
>>> + return (dma_addr_t)(adc->common->phys_base + DFSDM_RDATAR(adc->fl_id));
>>> +};
>>> +
>>> +/* Register callback to treat underrun and overrun issues */
>>> +static void stm32_dfsdm_register_xrun_cb(struct stm32_dfsdm_adc *adc,
>>> + void (*overrun_cb)(void *context),
>>> + void *context)
>>> +{
>>> + struct iio_dev *iio = iio_priv_to_dev(adc);
>>> +
>>> + dev_dbg(&iio->dev, "%s\n", __func__);
>>> + adc->overrun_cb = overrun_cb;
>>> + adc->cb_context = context;
>>> +};
>>> +
>>> +const struct stm32_adfsdm_codec_ops stm32_dfsdm_audio_ops = {
>>> + .set_sysclk = stm32_dfsdm_set_sysclk,
>>> + .set_hwparam = stm32_dfsdm_set_hwparam,
>>> + .audio_startup = stm32_dfsdm_audio_startup,
>>> + .audio_shutdown = stm32_dfsdm_audio_shutdown,
>>> + .register_xrun_cb = stm32_dfsdm_register_xrun_cb,
>>> + .get_dma_source = stm32_dfsdm_get_dma_source
>>> +};
>> Hmm. I'm wondering if it might make sense to farm the audio stuff off
>> to a separate file. Potentially we'll have systems that are built with
>> no audio support at all, so would be odd to have this stuff still provided.
> Ok, this make sense if the API become generic.
Probably worth doing even if we don't get more generic. Which is not to say
I'm not in favour of more generic!
>>
>> What do you think? Also provides an obvious clean bit to be Mark's problem
>> (even if it's in the IIO directory ;)
> I can't answer instead of Mark,( and perhaps i misunderstood...) but
> regarding HDMI story (drivers shared between ASoC and DRM), not sure
> that Mark accepts to have an ASoC drivers in IIO directory. So need a
> part in ASoC that is customer of IIO driver...
Sure. That makes sense. Not sure exactly where the divide occurs.
If we end up with some non trivial audio specific code left behind in
the IIO driver (to facilitate the bridge) then I'd still like that
to be in a separate file within IIO with build magic to drop it if
audio support isn't configured.
>
>>> +
>>> +static int stm32_dfsdm_adc_chan_init_one(struct iio_dev *indio_dev,
>>> + struct iio_chan_spec *chan,
>>> + int chan_idx)
>>> +{
>>> + struct iio_chan_spec *ch = &chan[chan_idx];
>>> + struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
>>> + int ret;
>>> +
>>> + dev_dbg(&indio_dev->dev, "%s:\n", __func__);
>>> + 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;
>>> + }
>>> +
>>> + 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;
>>> + }
>>> +
>>> + ch->type = IIO_VOLTAGE;
>>> + ch->indexed = 1;
>>> + ch->scan_index = chan_idx;
>>> + if (adc->mode == DFSDM_ADC) {
>>> + /*
>>> + * IIO_CHAN_INFO_RAW: used to compute regular conversion
>>> + * IIO_CHAN_INFO_SAMP_FREQ: used to indicate sampling frequency
>>> + * IIO_CHAN_INFO_OVERSAMPLING_RATIO: used set oversampling
>>> + */
>>> + ch->info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
>>> + BIT(IIO_CHAN_INFO_SAMP_FREQ) |
>>> + BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO);
>> Very nice. I was just thinking you should do this before I got here.
>> Channels with no properties but still with an existence from the point of
>> view of consumers using the buffered interface. Potentially you 'could'
>> provide some of the info as read only but why bother...
>>> + }
>>> +
>>> + ch->scan_type.sign = 'u';
>>> + ch->scan_type.realbits = 24;
>>> + ch->scan_type.storagebits = 32;
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int stm32_dfsdm_adc_chan_init(struct iio_dev *indio_dev)
>>> +{
>>> + struct iio_chan_spec *channels;
>>> + struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
>>> + unsigned int num_ch;
>>> + int ret, chan_idx;
>>> +
>>> + num_ch = of_property_count_u32_elems(indio_dev->dev.of_node,
>>> + "st,adc-channels");
>>> + if (num_ch < 0 || num_ch >= adc->common->num_chs) {
>>> + dev_err(&indio_dev->dev, "Bad st,adc-channels?\n");
>>> + return num_ch < 0 ? num_ch : -EINVAL;
>>> + }
>>> +
>>> + channels = devm_kcalloc(&indio_dev->dev, num_ch, sizeof(*channels),
>>> + GFP_KERNEL);
>>> + if (!channels)
>>> + return -ENOMEM;
>>> +
>>> + if (adc->mode == DFSDM_ADC) {
>>> + /*
>>> + * Bind to sd modulator iio device for ADC only.
>>> + * For Audio the PDM microphone will be handled by ASoC
>>> + */
>>> + adc->hwc = iio_hw_consumer_alloc(&indio_dev->dev);
>>> + if (IS_ERR(adc->hwc)) {
>>> + dev_err(&indio_dev->dev, "no backend found\n");
>> Deferred probing a possibility? I'm not quite sure and you know what is going
>> on here better than me ;)
> Reading your comment i have a doubt... i will cross check
> Idea here is that there is a customer-provider relationchip with the
> sd-modulator driver. So need that sd-modulator driver is probed first.
Should be fine, I hadn't thought that through.
>
>>> + return PTR_ERR(adc->hwc);
>>> + }
>>> + }
>>> +
>>> + for (chan_idx = 0; chan_idx < num_ch; chan_idx++) {
>>> + ret = stm32_dfsdm_adc_chan_init_one(indio_dev, channels,
>>> + chan_idx);
>>> + if (ret < 0)
>>> + goto free_hwc;
>>> + }
>>> +
>>> + indio_dev->num_channels = num_ch;
>>> + indio_dev->channels = channels;
>>> +
>>> + return 0;
>>> +
>>> +free_hwc:
>>> + if (adc->hwc)
>>> + iio_hw_consumer_free(adc->hwc);
>>> + return ret;
>>> +}
>>> +
> [...]
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