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stm32-dfsdm-adc.c
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// SPDX-License-Identifier: GPL-2.0
/*
* This file is the ADC part of the STM32 DFSDM driver
*
* Copyright (C) 2017, STMicroelectronics - All Rights Reserved
* Author: Arnaud Pouliquen <[email protected]>.
*/
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/iio/adc/stm32-dfsdm-adc.h>
#include <linux/iio/buffer.h>
#include <linux/iio/hw-consumer.h>
#include <linux/iio/sysfs.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/module.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/slab.h>
#include "stm32-dfsdm.h"
#define DFSDM_DMA_BUFFER_SIZE (4 * PAGE_SIZE)
/* 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
/* Limit filter output resolution to 31 bits. (i.e. sample range is +/-2^30) */
#define DFSDM_DATA_MAX BIT(30)
/*
* Data are output as two's complement data in a 24 bit field.
* Data from filters are in the range +/-2^(n-1)
* 2^(n-1) maximum positive value cannot be coded in 2's complement n bits
* An extra bit is required to avoid wrap-around of the binary code for 2^(n-1)
* So, the resolution of samples from filter is actually limited to 23 bits
*/
#define DFSDM_DATA_RES 24
/* Filter configuration */
#define DFSDM_CR1_CFG_MASK (DFSDM_CR1_RCH_MASK | DFSDM_CR1_RCONT_MASK | \
DFSDM_CR1_RSYNC_MASK | DFSDM_CR1_JSYNC_MASK | \
DFSDM_CR1_JSCAN_MASK)
enum sd_converter_type {
DFSDM_AUDIO,
DFSDM_IIO,
};
struct stm32_dfsdm_dev_data {
int type;
int (*init)(struct device *dev, 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 nconv;
unsigned long smask;
/* ADC specific */
unsigned int oversamp;
struct iio_hw_consumer *hwc;
struct completion completion;
u32 *buffer;
/* Audio specific */
unsigned int spi_freq; /* SPI bus clock frequency */
unsigned int sample_freq; /* Sample frequency after filter decimation */
int (*cb)(const void *data, size_t size, void *cb_priv);
void *cb_priv;
/* DMA */
u8 *rx_buf;
unsigned int bufi; /* Buffer current position */
unsigned int buf_sz; /* Buffer size */
struct dma_chan *dma_chan;
dma_addr_t dma_buf;
};
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;
}
/**
* struct stm32_dfsdm_trig_info - DFSDM trigger info
* @name: name of the trigger, corresponding to its source
* @jextsel: trigger signal selection
*/
struct stm32_dfsdm_trig_info {
const char *name;
unsigned int jextsel;
};
/* hardware injected trigger enable, edge selection */
enum stm32_dfsdm_jexten {
STM32_DFSDM_JEXTEN_DISABLED,
STM32_DFSDM_JEXTEN_RISING_EDGE,
STM32_DFSDM_JEXTEN_FALLING_EDGE,
STM32_DFSDM_EXTEN_BOTH_EDGES,
};
static const struct stm32_dfsdm_trig_info stm32_dfsdm_trigs[] = {
{ TIM1_TRGO, 0 },
{ TIM1_TRGO2, 1 },
{ TIM8_TRGO, 2 },
{ TIM8_TRGO2, 3 },
{ TIM3_TRGO, 4 },
{ TIM4_TRGO, 5 },
{ TIM16_OC1, 6 },
{ TIM6_TRGO, 7 },
{ TIM7_TRGO, 8 },
{ LPTIM1_OUT, 26 },
{ LPTIM2_OUT, 27 },
{ LPTIM3_OUT, 28 },
{},
};
static int stm32_dfsdm_get_jextsel(struct iio_dev *indio_dev,
struct iio_trigger *trig)
{
int i;
/* lookup triggers registered by stm32 timer trigger driver */
for (i = 0; stm32_dfsdm_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(stm32_dfsdm_trigs[i].name, trig->name)) {
return stm32_dfsdm_trigs[i].jextsel;
}
}
return -EINVAL;
}
static int stm32_dfsdm_compute_osrs(struct stm32_dfsdm_filter *fl,
unsigned int fast, unsigned int oversamp)
{
unsigned int i, d, fosr, iosr;
u64 res, max;
int bits, shift;
unsigned int m = 1; /* multiplication factor */
unsigned int p = fl->ford; /* filter order (ford) */
struct stm32_dfsdm_filter_osr *flo = &fl->flo[fast];
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 maximize data output resolution.
*/
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_DATA_MAX)
break;
}
if (res > DFSDM_DATA_MAX)
continue;
res = res * (u64)m * (u64)iosr;
if (res > DFSDM_DATA_MAX)
continue;
if (res >= flo->res) {
flo->res = res;
flo->fosr = fosr;
flo->iosr = iosr;
bits = fls(flo->res);
/* 8 LBSs in data register contain chan info */
max = flo->res << 8;
/* if resolution is not a power of two */
if (flo->res > BIT(bits - 1))
bits++;
else
max--;
shift = DFSDM_DATA_RES - bits;
/*
* Compute right/left shift
* Right shift is performed by hardware
* when transferring samples to data register.
* Left shift is done by software on buffer
*/
if (shift > 0) {
/* Resolution is lower than 24 bits */
flo->rshift = 0;
flo->lshift = shift;
} else {
/*
* If resolution is 24 bits or more,
* max positive value may be ambiguous
* (equal to max negative value as sign
* bit is dropped).
* Reduce resolution to 23 bits (rshift)
* to keep the sign on bit 23 and treat
* saturation before rescaling on 24
* bits (lshift).
*/
flo->rshift = 1 - shift;
flo->lshift = 1;
max >>= flo->rshift;
}
flo->max = (s32)max;
flo->bits = bits;
pr_debug("%s: fast %d, fosr %d, iosr %d, res 0x%llx/%d bits, rshift %d, lshift %d\n",
__func__, fast, flo->fosr, flo->iosr,
flo->res, bits, flo->rshift,
flo->lshift);
}
}
}
if (!flo->res)
return -EINVAL;
return 0;
}
static int stm32_dfsdm_compute_all_osrs(struct iio_dev *indio_dev,
unsigned int oversamp)
{
struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
struct stm32_dfsdm_filter *fl = &adc->dfsdm->fl_list[adc->fl_id];
int ret0, ret1;
memset(&fl->flo[0], 0, sizeof(fl->flo[0]));
memset(&fl->flo[1], 0, sizeof(fl->flo[1]));
ret0 = stm32_dfsdm_compute_osrs(fl, 0, oversamp);
ret1 = stm32_dfsdm_compute_osrs(fl, 1, oversamp);
if (ret0 < 0 && ret1 < 0) {
dev_err(&indio_dev->dev,
"Filter parameters not found: errors %d/%d\n",
ret0, ret1);
return -EINVAL;
}
return 0;
}
static int stm32_dfsdm_start_channel(struct iio_dev *indio_dev)
{
struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
struct regmap *regmap = adc->dfsdm->regmap;
const struct iio_chan_spec *chan;
unsigned int bit;
int ret;
for_each_set_bit(bit, &adc->smask, sizeof(adc->smask) * BITS_PER_BYTE) {
chan = indio_dev->channels + bit;
ret = regmap_update_bits(regmap, DFSDM_CHCFGR1(chan->channel),
DFSDM_CHCFGR1_CHEN_MASK,
DFSDM_CHCFGR1_CHEN(1));
if (ret < 0)
return ret;
}
return 0;
}
static void stm32_dfsdm_stop_channel(struct iio_dev *indio_dev)
{
struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
struct regmap *regmap = adc->dfsdm->regmap;
const struct iio_chan_spec *chan;
unsigned int bit;
for_each_set_bit(bit, &adc->smask, sizeof(adc->smask) * BITS_PER_BYTE) {
chan = indio_dev->channels + bit;
regmap_update_bits(regmap, DFSDM_CHCFGR1(chan->channel),
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_adc *adc,
unsigned int fl_id,
struct iio_trigger *trig)
{
struct stm32_dfsdm *dfsdm = adc->dfsdm;
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;
/* Nothing more to do for injected (scan mode/triggered) conversions */
if (adc->nconv > 1 || trig)
return 0;
/* Software start (single or continuous) regular conversion */
return regmap_update_bits(dfsdm->regmap, DFSDM_CR1(fl_id),
DFSDM_CR1_RSWSTART_MASK,
DFSDM_CR1_RSWSTART(1));
}
static 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_set_trig(struct iio_dev *indio_dev,
unsigned int fl_id,
struct iio_trigger *trig)
{
struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
struct regmap *regmap = adc->dfsdm->regmap;
u32 jextsel = 0, jexten = STM32_DFSDM_JEXTEN_DISABLED;
int ret;
if (trig) {
ret = stm32_dfsdm_get_jextsel(indio_dev, trig);
if (ret < 0)
return ret;
/* set trigger source and polarity (default to rising edge) */
jextsel = ret;
jexten = STM32_DFSDM_JEXTEN_RISING_EDGE;
}
ret = regmap_update_bits(regmap, DFSDM_CR1(fl_id),
DFSDM_CR1_JEXTSEL_MASK | DFSDM_CR1_JEXTEN_MASK,
DFSDM_CR1_JEXTSEL(jextsel) |
DFSDM_CR1_JEXTEN(jexten));
if (ret < 0)
return ret;
return 0;
}
static int stm32_dfsdm_channels_configure(struct iio_dev *indio_dev,
unsigned int fl_id,
struct iio_trigger *trig)
{
struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
struct regmap *regmap = adc->dfsdm->regmap;
struct stm32_dfsdm_filter *fl = &adc->dfsdm->fl_list[fl_id];
struct stm32_dfsdm_filter_osr *flo = &fl->flo[0];
const struct iio_chan_spec *chan;
unsigned int bit;
int ret;
fl->fast = 0;
/*
* In continuous mode, use fast mode configuration,
* if it provides a better resolution.
*/
if (adc->nconv == 1 && !trig &&
(indio_dev->currentmode & INDIO_BUFFER_SOFTWARE)) {
if (fl->flo[1].res >= fl->flo[0].res) {
fl->fast = 1;
flo = &fl->flo[1];
}
}
if (!flo->res)
return -EINVAL;
dev_dbg(&indio_dev->dev, "Samples actual resolution: %d bits",
min(flo->bits, (u32)DFSDM_DATA_RES - 1));
for_each_set_bit(bit, &adc->smask,
sizeof(adc->smask) * BITS_PER_BYTE) {
chan = indio_dev->channels + bit;
ret = regmap_update_bits(regmap,
DFSDM_CHCFGR2(chan->channel),
DFSDM_CHCFGR2_DTRBS_MASK,
DFSDM_CHCFGR2_DTRBS(flo->rshift));
if (ret)
return ret;
}
return 0;
}
static int stm32_dfsdm_filter_configure(struct iio_dev *indio_dev,
unsigned int fl_id,
struct iio_trigger *trig)
{
struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
struct regmap *regmap = adc->dfsdm->regmap;
struct stm32_dfsdm_filter *fl = &adc->dfsdm->fl_list[fl_id];
struct stm32_dfsdm_filter_osr *flo = &fl->flo[fl->fast];
u32 cr1;
const struct iio_chan_spec *chan;
unsigned int bit, jchg = 0;
int ret;
/* Average integrator oversampling */
ret = regmap_update_bits(regmap, DFSDM_FCR(fl_id), DFSDM_FCR_IOSR_MASK,
DFSDM_FCR_IOSR(flo->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(flo->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;
ret = stm32_dfsdm_filter_set_trig(indio_dev, fl_id, trig);
if (ret)
return ret;
ret = regmap_update_bits(regmap, DFSDM_CR1(fl_id),
DFSDM_CR1_FAST_MASK,
DFSDM_CR1_FAST(fl->fast));
if (ret)
return ret;
/*
* DFSDM modes configuration W.R.T audio/iio type modes
* ----------------------------------------------------------------
* Modes | regular | regular | injected | injected |
* | | continuous | | + scan |
* --------------|---------|--------------|----------|------------|
* single conv | x | | | |
* (1 chan) | | | | |
* --------------|---------|--------------|----------|------------|
* 1 Audio chan | | sample freq | | |
* | | or sync_mode | | |
* --------------|---------|--------------|----------|------------|
* 1 IIO chan | | sample freq | trigger | |
* | | or sync_mode | | |
* --------------|---------|--------------|----------|------------|
* 2+ IIO chans | | | | trigger or |
* | | | | sync_mode |
* ----------------------------------------------------------------
*/
if (adc->nconv == 1 && !trig) {
bit = __ffs(adc->smask);
chan = indio_dev->channels + bit;
/* Use regular conversion for single channel without trigger */
cr1 = DFSDM_CR1_RCH(chan->channel);
/* Continuous conversions triggered by SPI clk in buffer mode */
if (indio_dev->currentmode & INDIO_BUFFER_SOFTWARE)
cr1 |= DFSDM_CR1_RCONT(1);
cr1 |= DFSDM_CR1_RSYNC(fl->sync_mode);
} else {
/* Use injected conversion for multiple channels */
for_each_set_bit(bit, &adc->smask,
sizeof(adc->smask) * BITS_PER_BYTE) {
chan = indio_dev->channels + bit;
jchg |= BIT(chan->channel);
}
ret = regmap_write(regmap, DFSDM_JCHGR(fl_id), jchg);
if (ret < 0)
return ret;
/* Use scan mode for multiple channels */
cr1 = DFSDM_CR1_JSCAN((adc->nconv > 1) ? 1 : 0);
/*
* Continuous conversions not supported in injected mode,
* either use:
* - conversions in sync with filter 0
* - triggered conversions
*/
if (!fl->sync_mode && !trig)
return -EINVAL;
cr1 |= DFSDM_CR1_JSYNC(fl->sync_mode);
}
return regmap_update_bits(regmap, DFSDM_CR1(fl_id), DFSDM_CR1_CFG_MASK,
cr1);
}
static 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 ssize_t dfsdm_adc_audio_get_spiclk(struct iio_dev *indio_dev,
uintptr_t priv,
const struct iio_chan_spec *chan,
char *buf)
{
struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
return snprintf(buf, PAGE_SIZE, "%d\n", adc->spi_freq);
}
static int dfsdm_adc_set_samp_freq(struct iio_dev *indio_dev,
unsigned int sample_freq,
unsigned int spi_freq)
{
struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
unsigned int oversamp;
int ret;
oversamp = DIV_ROUND_CLOSEST(spi_freq, sample_freq);
if (spi_freq % sample_freq)
dev_dbg(&indio_dev->dev,
"Rate not accurate. requested (%u), actual (%u)\n",
sample_freq, spi_freq / oversamp);
ret = stm32_dfsdm_compute_all_osrs(indio_dev, oversamp);
if (ret < 0)
return ret;
adc->sample_freq = spi_freq / oversamp;
adc->oversamp = oversamp;
return 0;
}
static ssize_t dfsdm_adc_audio_set_spiclk(struct iio_dev *indio_dev,
uintptr_t priv,
const struct iio_chan_spec *chan,
const char *buf, size_t len)
{
struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
struct stm32_dfsdm_channel *ch = &adc->dfsdm->ch_list[chan->channel];
unsigned int sample_freq = adc->sample_freq;
unsigned int spi_freq;
int ret;
dev_err(&indio_dev->dev, "enter %s\n", __func__);
/* If DFSDM is master on SPI, SPI freq can not be updated */
if (ch->src != DFSDM_CHANNEL_SPI_CLOCK_EXTERNAL)
return -EPERM;
ret = kstrtoint(buf, 0, &spi_freq);
if (ret)
return ret;
if (!spi_freq)
return -EINVAL;
if (sample_freq) {
ret = dfsdm_adc_set_samp_freq(indio_dev, sample_freq, spi_freq);
if (ret < 0)
return ret;
}
adc->spi_freq = spi_freq;
return len;
}
static int stm32_dfsdm_start_conv(struct iio_dev *indio_dev,
struct iio_trigger *trig)
{
struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
struct regmap *regmap = adc->dfsdm->regmap;
int ret;
ret = stm32_dfsdm_channels_configure(indio_dev, adc->fl_id, trig);
if (ret < 0)
return ret;
ret = stm32_dfsdm_start_channel(indio_dev);
if (ret < 0)
return ret;
ret = stm32_dfsdm_filter_configure(indio_dev, adc->fl_id, trig);
if (ret < 0)
goto stop_channels;
ret = stm32_dfsdm_start_filter(adc, adc->fl_id, trig);
if (ret < 0)
goto filter_unconfigure;
return 0;
filter_unconfigure:
regmap_update_bits(regmap, DFSDM_CR1(adc->fl_id),
DFSDM_CR1_CFG_MASK, 0);
stop_channels:
stm32_dfsdm_stop_channel(indio_dev);
return ret;
}
static void stm32_dfsdm_stop_conv(struct iio_dev *indio_dev)
{
struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
struct regmap *regmap = adc->dfsdm->regmap;
stm32_dfsdm_stop_filter(adc->dfsdm, adc->fl_id);
regmap_update_bits(regmap, DFSDM_CR1(adc->fl_id),
DFSDM_CR1_CFG_MASK, 0);
stm32_dfsdm_stop_channel(indio_dev);
}
static int stm32_dfsdm_set_watermark(struct iio_dev *indio_dev,
unsigned int val)
{
struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
unsigned int watermark = DFSDM_DMA_BUFFER_SIZE / 2;
unsigned int rx_buf_sz = DFSDM_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 pushed to ASoC side.
*/
watermark = min(watermark, val * (unsigned int)(sizeof(u32)));
adc->buf_sz = min(rx_buf_sz, watermark * 2 * adc->nconv);
return 0;
}
static unsigned int stm32_dfsdm_adc_dma_residue(struct stm32_dfsdm_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->buf_sz - state.residue;
unsigned int size;
/* Return available bytes */
if (i >= adc->bufi)
size = i - adc->bufi;
else
size = adc->buf_sz + i - adc->bufi;
return size;
}
return 0;
}
static inline void stm32_dfsdm_process_data(struct stm32_dfsdm_adc *adc,
s32 *buffer)
{
struct stm32_dfsdm_filter *fl = &adc->dfsdm->fl_list[adc->fl_id];
struct stm32_dfsdm_filter_osr *flo = &fl->flo[fl->fast];
unsigned int i = adc->nconv;
s32 *ptr = buffer;
while (i--) {
/* Mask 8 LSB that contains the channel ID */
*ptr &= 0xFFFFFF00;
/* Convert 2^(n-1) sample to 2^(n-1)-1 to avoid wrap-around */
if (*ptr > flo->max)
*ptr -= 1;
/*
* Samples from filter are retrieved with 23 bits resolution
* or less. Shift left to align MSB on 24 bits.
*/
*ptr <<= flo->lshift;
ptr++;
}
}
static void stm32_dfsdm_dma_buffer_done(void *data)
{
struct iio_dev *indio_dev = data;
struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
int available = stm32_dfsdm_adc_dma_residue(adc);
size_t old_pos;
/*
* FIXME: In Kernel interface does not support cyclic DMA buffer,and
* offers only an interface to push data samples per samples.
* For this reason IIO buffer interface is not used and interface is
* bypassed using a private callback registered by ASoC.
* This should be a temporary solution waiting a cyclic DMA engine
* support in IIO.
*/
dev_dbg(&indio_dev->dev, "%s: pos = %d, available = %d\n", __func__,
adc->bufi, available);
old_pos = adc->bufi;
while (available >= indio_dev->scan_bytes) {
s32 *buffer = (s32 *)&adc->rx_buf[adc->bufi];
stm32_dfsdm_process_data(adc, buffer);
available -= indio_dev->scan_bytes;
adc->bufi += indio_dev->scan_bytes;
if (adc->bufi >= adc->buf_sz) {
if (adc->cb)
adc->cb(&adc->rx_buf[old_pos],
adc->buf_sz - old_pos, adc->cb_priv);
adc->bufi = 0;
old_pos = 0;
}
/*
* 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).
*/
if (adc->dev_data->type == DFSDM_IIO)
iio_push_to_buffers(indio_dev, buffer);
}
if (adc->cb)
adc->cb(&adc->rx_buf[old_pos], adc->bufi - old_pos,
adc->cb_priv);
}
static int stm32_dfsdm_adc_dma_start(struct iio_dev *indio_dev)
{
struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
/*
* The DFSDM supports half-word transfers. However, for 16 bits record,
* 4 bytes buswidth is kept, to avoid losing samples LSBs when left
* shift is required.
*/
struct dma_slave_config config = {
.src_addr = (dma_addr_t)adc->dfsdm->phys_base,
.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES,
};
struct dma_async_tx_descriptor *desc;
dma_cookie_t cookie;
int ret;
if (!adc->dma_chan)
return -EINVAL;
dev_dbg(&indio_dev->dev, "%s size=%d watermark=%d\n", __func__,
adc->buf_sz, adc->buf_sz / 2);
if (adc->nconv == 1 && !indio_dev->trig)
config.src_addr += DFSDM_RDATAR(adc->fl_id);
else
config.src_addr += DFSDM_JDATAR(adc->fl_id);
ret = dmaengine_slave_config(adc->dma_chan, &config);
if (ret)
return ret;
/* Prepare a DMA cyclic transaction */
desc = dmaengine_prep_dma_cyclic(adc->dma_chan,
adc->dma_buf,
adc->buf_sz, adc->buf_sz / 2,
DMA_DEV_TO_MEM,
DMA_PREP_INTERRUPT);
if (!desc)
return -EBUSY;
desc->callback = stm32_dfsdm_dma_buffer_done;
desc->callback_param = indio_dev;
cookie = dmaengine_submit(desc);
ret = dma_submit_error(cookie);
if (ret)
goto err_stop_dma;
/* Issue pending DMA requests */
dma_async_issue_pending(adc->dma_chan);
if (adc->nconv == 1 && !indio_dev->trig) {
/* Enable regular DMA transfer*/
ret = regmap_update_bits(adc->dfsdm->regmap,
DFSDM_CR1(adc->fl_id),
DFSDM_CR1_RDMAEN_MASK,
DFSDM_CR1_RDMAEN_MASK);
} else {
/* Enable injected DMA transfer*/
ret = regmap_update_bits(adc->dfsdm->regmap,
DFSDM_CR1(adc->fl_id),
DFSDM_CR1_JDMAEN_MASK,
DFSDM_CR1_JDMAEN_MASK);
}
if (ret < 0)
goto err_stop_dma;
return 0;
err_stop_dma:
dmaengine_terminate_all(adc->dma_chan);
return ret;
}
static void stm32_dfsdm_adc_dma_stop(struct iio_dev *indio_dev)
{
struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
if (!adc->dma_chan)
return;
regmap_update_bits(adc->dfsdm->regmap, DFSDM_CR1(adc->fl_id),
DFSDM_CR1_RDMAEN_MASK | DFSDM_CR1_JDMAEN_MASK, 0);
dmaengine_terminate_all(adc->dma_chan);
}
static int stm32_dfsdm_update_scan_mode(struct iio_dev *indio_dev,
const unsigned long *scan_mask)
{
struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
adc->nconv = bitmap_weight(scan_mask, indio_dev->masklength);
adc->smask = *scan_mask;
dev_dbg(&indio_dev->dev, "nconv=%d mask=%lx\n", adc->nconv, *scan_mask);
return 0;
}