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OpenCloudOS-Kernel/drivers/iio/adc/at91-sama5d2_adc.c

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/*
* Atmel ADC driver for SAMA5D2 devices and compatible.
*
* Copyright (C) 2015 Atmel,
* 2015 Ludovic Desroches <ludovic.desroches@atmel.com>
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* 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.
*/
#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/pinctrl/consumer.h>
#include <linux/regulator/consumer.h>
/* Control Register */
#define AT91_SAMA5D2_CR 0x00
/* Software Reset */
#define AT91_SAMA5D2_CR_SWRST BIT(0)
/* Start Conversion */
#define AT91_SAMA5D2_CR_START BIT(1)
/* Touchscreen Calibration */
#define AT91_SAMA5D2_CR_TSCALIB BIT(2)
/* Comparison Restart */
#define AT91_SAMA5D2_CR_CMPRST BIT(4)
/* Mode Register */
#define AT91_SAMA5D2_MR 0x04
/* Trigger Selection */
#define AT91_SAMA5D2_MR_TRGSEL(v) ((v) << 1)
/* ADTRG */
#define AT91_SAMA5D2_MR_TRGSEL_TRIG0 0
/* TIOA0 */
#define AT91_SAMA5D2_MR_TRGSEL_TRIG1 1
/* TIOA1 */
#define AT91_SAMA5D2_MR_TRGSEL_TRIG2 2
/* TIOA2 */
#define AT91_SAMA5D2_MR_TRGSEL_TRIG3 3
/* PWM event line 0 */
#define AT91_SAMA5D2_MR_TRGSEL_TRIG4 4
/* PWM event line 1 */
#define AT91_SAMA5D2_MR_TRGSEL_TRIG5 5
/* TIOA3 */
#define AT91_SAMA5D2_MR_TRGSEL_TRIG6 6
/* RTCOUT0 */
#define AT91_SAMA5D2_MR_TRGSEL_TRIG7 7
/* Sleep Mode */
#define AT91_SAMA5D2_MR_SLEEP BIT(5)
/* Fast Wake Up */
#define AT91_SAMA5D2_MR_FWUP BIT(6)
/* Prescaler Rate Selection */
#define AT91_SAMA5D2_MR_PRESCAL(v) ((v) << AT91_SAMA5D2_MR_PRESCAL_OFFSET)
#define AT91_SAMA5D2_MR_PRESCAL_OFFSET 8
#define AT91_SAMA5D2_MR_PRESCAL_MAX 0xff
#define AT91_SAMA5D2_MR_PRESCAL_MASK GENMASK(15, 8)
/* Startup Time */
#define AT91_SAMA5D2_MR_STARTUP(v) ((v) << 16)
#define AT91_SAMA5D2_MR_STARTUP_MASK GENMASK(19, 16)
/* Analog Change */
#define AT91_SAMA5D2_MR_ANACH BIT(23)
/* Tracking Time */
#define AT91_SAMA5D2_MR_TRACKTIM(v) ((v) << 24)
#define AT91_SAMA5D2_MR_TRACKTIM_MAX 0xff
/* Transfer Time */
#define AT91_SAMA5D2_MR_TRANSFER(v) ((v) << 28)
#define AT91_SAMA5D2_MR_TRANSFER_MAX 0x3
/* Use Sequence Enable */
#define AT91_SAMA5D2_MR_USEQ BIT(31)
/* Channel Sequence Register 1 */
#define AT91_SAMA5D2_SEQR1 0x08
/* Channel Sequence Register 2 */
#define AT91_SAMA5D2_SEQR2 0x0c
/* Channel Enable Register */
#define AT91_SAMA5D2_CHER 0x10
/* Channel Disable Register */
#define AT91_SAMA5D2_CHDR 0x14
/* Channel Status Register */
#define AT91_SAMA5D2_CHSR 0x18
/* Last Converted Data Register */
#define AT91_SAMA5D2_LCDR 0x20
/* Interrupt Enable Register */
#define AT91_SAMA5D2_IER 0x24
/* Interrupt Enable Register - general overrun error */
#define AT91_SAMA5D2_IER_GOVRE BIT(25)
/* Interrupt Disable Register */
#define AT91_SAMA5D2_IDR 0x28
/* Interrupt Mask Register */
#define AT91_SAMA5D2_IMR 0x2c
/* Interrupt Status Register */
#define AT91_SAMA5D2_ISR 0x30
/* Last Channel Trigger Mode Register */
#define AT91_SAMA5D2_LCTMR 0x34
/* Last Channel Compare Window Register */
#define AT91_SAMA5D2_LCCWR 0x38
/* Overrun Status Register */
#define AT91_SAMA5D2_OVER 0x3c
/* Extended Mode Register */
#define AT91_SAMA5D2_EMR 0x40
/* Compare Window Register */
#define AT91_SAMA5D2_CWR 0x44
/* Channel Gain Register */
#define AT91_SAMA5D2_CGR 0x48
/* Channel Offset Register */
#define AT91_SAMA5D2_COR 0x4c
#define AT91_SAMA5D2_COR_DIFF_OFFSET 16
/* Channel Data Register 0 */
#define AT91_SAMA5D2_CDR0 0x50
/* Analog Control Register */
#define AT91_SAMA5D2_ACR 0x94
/* Touchscreen Mode Register */
#define AT91_SAMA5D2_TSMR 0xb0
/* Touchscreen X Position Register */
#define AT91_SAMA5D2_XPOSR 0xb4
/* Touchscreen Y Position Register */
#define AT91_SAMA5D2_YPOSR 0xb8
/* Touchscreen Pressure Register */
#define AT91_SAMA5D2_PRESSR 0xbc
/* Trigger Register */
#define AT91_SAMA5D2_TRGR 0xc0
/* Mask for TRGMOD field of TRGR register */
#define AT91_SAMA5D2_TRGR_TRGMOD_MASK GENMASK(2, 0)
/* No trigger, only software trigger can start conversions */
#define AT91_SAMA5D2_TRGR_TRGMOD_NO_TRIGGER 0
/* Trigger Mode external trigger rising edge */
#define AT91_SAMA5D2_TRGR_TRGMOD_EXT_TRIG_RISE 1
/* Trigger Mode external trigger falling edge */
#define AT91_SAMA5D2_TRGR_TRGMOD_EXT_TRIG_FALL 2
/* Trigger Mode external trigger any edge */
#define AT91_SAMA5D2_TRGR_TRGMOD_EXT_TRIG_ANY 3
/* Correction Select Register */
#define AT91_SAMA5D2_COSR 0xd0
/* Correction Value Register */
#define AT91_SAMA5D2_CVR 0xd4
/* Channel Error Correction Register */
#define AT91_SAMA5D2_CECR 0xd8
/* Write Protection Mode Register */
#define AT91_SAMA5D2_WPMR 0xe4
/* Write Protection Status Register */
#define AT91_SAMA5D2_WPSR 0xe8
/* Version Register */
#define AT91_SAMA5D2_VERSION 0xfc
#define AT91_SAMA5D2_HW_TRIG_CNT 3
#define AT91_SAMA5D2_SINGLE_CHAN_CNT 12
#define AT91_SAMA5D2_DIFF_CHAN_CNT 6
/*
* Maximum number of bytes to hold conversion from all channels
* without the timestamp.
*/
#define AT91_BUFFER_MAX_CONVERSION_BYTES ((AT91_SAMA5D2_SINGLE_CHAN_CNT + \
AT91_SAMA5D2_DIFF_CHAN_CNT) * 2)
/* This total must also include the timestamp */
#define AT91_BUFFER_MAX_BYTES (AT91_BUFFER_MAX_CONVERSION_BYTES + 8)
#define AT91_BUFFER_MAX_HWORDS (AT91_BUFFER_MAX_BYTES / 2)
#define AT91_HWFIFO_MAX_SIZE_STR "128"
#define AT91_HWFIFO_MAX_SIZE 128
#define AT91_SAMA5D2_CHAN_SINGLE(num, addr) \
{ \
.type = IIO_VOLTAGE, \
.channel = num, \
.address = addr, \
.scan_index = num, \
.scan_type = { \
.sign = 'u', \
.realbits = 12, \
.storagebits = 16, \
}, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),\
.datasheet_name = "CH"#num, \
.indexed = 1, \
}
#define AT91_SAMA5D2_CHAN_DIFF(num, num2, addr) \
{ \
.type = IIO_VOLTAGE, \
.differential = 1, \
.channel = num, \
.channel2 = num2, \
.address = addr, \
.scan_index = num + AT91_SAMA5D2_SINGLE_CHAN_CNT, \
.scan_type = { \
.sign = 's', \
.realbits = 12, \
.storagebits = 16, \
}, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),\
.datasheet_name = "CH"#num"-CH"#num2, \
.indexed = 1, \
}
#define at91_adc_readl(st, reg) readl_relaxed(st->base + reg)
#define at91_adc_writel(st, reg, val) writel_relaxed(val, st->base + reg)
struct at91_adc_soc_info {
unsigned startup_time;
unsigned min_sample_rate;
unsigned max_sample_rate;
};
struct at91_adc_trigger {
char *name;
unsigned int trgmod_value;
unsigned int edge_type;
bool hw_trig;
};
/**
* at91_adc_dma - at91-sama5d2 dma information struct
* @dma_chan: the dma channel acquired
* @rx_buf: dma coherent allocated area
* @rx_dma_buf: dma handler for the buffer
* @phys_addr: physical address of the ADC base register
* @buf_idx: index inside the dma buffer where reading was last done
* @rx_buf_sz: size of buffer used by DMA operation
* @watermark: number of conversions to copy before DMA triggers irq
* @dma_ts: hold the start timestamp of dma operation
*/
struct at91_adc_dma {
struct dma_chan *dma_chan;
u8 *rx_buf;
dma_addr_t rx_dma_buf;
phys_addr_t phys_addr;
int buf_idx;
int rx_buf_sz;
int watermark;
s64 dma_ts;
};
struct at91_adc_state {
void __iomem *base;
int irq;
struct clk *per_clk;
struct regulator *reg;
struct regulator *vref;
int vref_uv;
struct iio_trigger *trig;
const struct at91_adc_trigger *selected_trig;
const struct iio_chan_spec *chan;
bool conversion_done;
u32 conversion_value;
struct at91_adc_soc_info soc_info;
wait_queue_head_t wq_data_available;
struct at91_adc_dma dma_st;
u16 buffer[AT91_BUFFER_MAX_HWORDS];
/*
* lock to prevent concurrent 'single conversion' requests through
* sysfs.
*/
struct mutex lock;
};
static const struct at91_adc_trigger at91_adc_trigger_list[] = {
{
.name = "external_rising",
.trgmod_value = AT91_SAMA5D2_TRGR_TRGMOD_EXT_TRIG_RISE,
.edge_type = IRQ_TYPE_EDGE_RISING,
.hw_trig = true,
},
{
.name = "external_falling",
.trgmod_value = AT91_SAMA5D2_TRGR_TRGMOD_EXT_TRIG_FALL,
.edge_type = IRQ_TYPE_EDGE_FALLING,
.hw_trig = true,
},
{
.name = "external_any",
.trgmod_value = AT91_SAMA5D2_TRGR_TRGMOD_EXT_TRIG_ANY,
.edge_type = IRQ_TYPE_EDGE_BOTH,
.hw_trig = true,
},
{
.name = "software",
.trgmod_value = AT91_SAMA5D2_TRGR_TRGMOD_NO_TRIGGER,
.edge_type = IRQ_TYPE_NONE,
.hw_trig = false,
},
};
static const struct iio_chan_spec at91_adc_channels[] = {
AT91_SAMA5D2_CHAN_SINGLE(0, 0x50),
AT91_SAMA5D2_CHAN_SINGLE(1, 0x54),
AT91_SAMA5D2_CHAN_SINGLE(2, 0x58),
AT91_SAMA5D2_CHAN_SINGLE(3, 0x5c),
AT91_SAMA5D2_CHAN_SINGLE(4, 0x60),
AT91_SAMA5D2_CHAN_SINGLE(5, 0x64),
AT91_SAMA5D2_CHAN_SINGLE(6, 0x68),
AT91_SAMA5D2_CHAN_SINGLE(7, 0x6c),
AT91_SAMA5D2_CHAN_SINGLE(8, 0x70),
AT91_SAMA5D2_CHAN_SINGLE(9, 0x74),
AT91_SAMA5D2_CHAN_SINGLE(10, 0x78),
AT91_SAMA5D2_CHAN_SINGLE(11, 0x7c),
AT91_SAMA5D2_CHAN_DIFF(0, 1, 0x50),
AT91_SAMA5D2_CHAN_DIFF(2, 3, 0x58),
AT91_SAMA5D2_CHAN_DIFF(4, 5, 0x60),
AT91_SAMA5D2_CHAN_DIFF(6, 7, 0x68),
AT91_SAMA5D2_CHAN_DIFF(8, 9, 0x70),
AT91_SAMA5D2_CHAN_DIFF(10, 11, 0x78),
IIO_CHAN_SOFT_TIMESTAMP(AT91_SAMA5D2_SINGLE_CHAN_CNT
+ AT91_SAMA5D2_DIFF_CHAN_CNT + 1),
};
static int at91_adc_configure_trigger(struct iio_trigger *trig, bool state)
{
struct iio_dev *indio = iio_trigger_get_drvdata(trig);
struct at91_adc_state *st = iio_priv(indio);
u32 status = at91_adc_readl(st, AT91_SAMA5D2_TRGR);
u8 bit;
/* clear TRGMOD */
status &= ~AT91_SAMA5D2_TRGR_TRGMOD_MASK;
if (state)
status |= st->selected_trig->trgmod_value;
/* set/unset hw trigger */
at91_adc_writel(st, AT91_SAMA5D2_TRGR, status);
for_each_set_bit(bit, indio->active_scan_mask, indio->num_channels) {
struct iio_chan_spec const *chan = indio->channels + bit;
if (state) {
at91_adc_writel(st, AT91_SAMA5D2_CHER,
BIT(chan->channel));
/* enable irq only if not using DMA */
if (!st->dma_st.dma_chan) {
at91_adc_writel(st, AT91_SAMA5D2_IER,
BIT(chan->channel));
}
} else {
/* disable irq only if not using DMA */
if (!st->dma_st.dma_chan) {
at91_adc_writel(st, AT91_SAMA5D2_IDR,
BIT(chan->channel));
}
at91_adc_writel(st, AT91_SAMA5D2_CHDR,
BIT(chan->channel));
}
}
return 0;
}
static int at91_adc_reenable_trigger(struct iio_trigger *trig)
{
struct iio_dev *indio = iio_trigger_get_drvdata(trig);
struct at91_adc_state *st = iio_priv(indio);
/* if we are using DMA, we must not reenable irq after each trigger */
if (st->dma_st.dma_chan)
return 0;
enable_irq(st->irq);
/* Needed to ACK the DRDY interruption */
at91_adc_readl(st, AT91_SAMA5D2_LCDR);
return 0;
}
static const struct iio_trigger_ops at91_adc_trigger_ops = {
.set_trigger_state = &at91_adc_configure_trigger,
.try_reenable = &at91_adc_reenable_trigger,
.validate_device = iio_trigger_validate_own_device,
};
static int at91_adc_dma_size_done(struct at91_adc_state *st)
{
struct dma_tx_state state;
enum dma_status status;
int i, size;
status = dmaengine_tx_status(st->dma_st.dma_chan,
st->dma_st.dma_chan->cookie,
&state);
if (status != DMA_IN_PROGRESS)
return 0;
/* Transferred length is size in bytes from end of buffer */
i = st->dma_st.rx_buf_sz - state.residue;
/* Return available bytes */
if (i >= st->dma_st.buf_idx)
size = i - st->dma_st.buf_idx;
else
size = st->dma_st.rx_buf_sz + i - st->dma_st.buf_idx;
return size;
}
static void at91_dma_buffer_done(void *data)
{
struct iio_dev *indio_dev = data;
iio_trigger_poll_chained(indio_dev->trig);
}
static int at91_adc_dma_start(struct iio_dev *indio_dev)
{
struct at91_adc_state *st = iio_priv(indio_dev);
struct dma_async_tx_descriptor *desc;
dma_cookie_t cookie;
int ret;
u8 bit;
if (!st->dma_st.dma_chan)
return 0;
/* we start a new DMA, so set buffer index to start */
st->dma_st.buf_idx = 0;
/*
* compute buffer size w.r.t. watermark and enabled channels.
* scan_bytes is aligned so we need an exact size for DMA
*/
st->dma_st.rx_buf_sz = 0;
for_each_set_bit(bit, indio_dev->active_scan_mask,
indio_dev->num_channels) {
struct iio_chan_spec const *chan = indio_dev->channels + bit;
st->dma_st.rx_buf_sz += chan->scan_type.storagebits / 8;
}
st->dma_st.rx_buf_sz *= st->dma_st.watermark;
/* Prepare a DMA cyclic transaction */
desc = dmaengine_prep_dma_cyclic(st->dma_st.dma_chan,
st->dma_st.rx_dma_buf,
st->dma_st.rx_buf_sz,
st->dma_st.rx_buf_sz / 2,
DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT);
if (!desc) {
dev_err(&indio_dev->dev, "cannot prepare DMA cyclic\n");
return -EBUSY;
}
desc->callback = at91_dma_buffer_done;
desc->callback_param = indio_dev;
cookie = dmaengine_submit(desc);
ret = dma_submit_error(cookie);
if (ret) {
dev_err(&indio_dev->dev, "cannot submit DMA cyclic\n");
dmaengine_terminate_async(st->dma_st.dma_chan);
return ret;
}
/* enable general overrun error signaling */
at91_adc_writel(st, AT91_SAMA5D2_IER, AT91_SAMA5D2_IER_GOVRE);
/* Issue pending DMA requests */
dma_async_issue_pending(st->dma_st.dma_chan);
/* consider current time as DMA start time for timestamps */
st->dma_st.dma_ts = iio_get_time_ns(indio_dev);
dev_dbg(&indio_dev->dev, "DMA cyclic started\n");
return 0;
}
static int at91_adc_buffer_postenable(struct iio_dev *indio_dev)
{
int ret;
ret = at91_adc_dma_start(indio_dev);
if (ret) {
dev_err(&indio_dev->dev, "buffer postenable failed\n");
return ret;
}
return iio_triggered_buffer_postenable(indio_dev);
}
static int at91_adc_buffer_predisable(struct iio_dev *indio_dev)
{
struct at91_adc_state *st = iio_priv(indio_dev);
int ret;
u8 bit;
ret = iio_triggered_buffer_predisable(indio_dev);
if (ret < 0)
dev_err(&indio_dev->dev, "buffer predisable failed\n");
if (!st->dma_st.dma_chan)
return ret;
/* if we are using DMA we must clear registers and end DMA */
dmaengine_terminate_sync(st->dma_st.dma_chan);
/*
* For each enabled channel we must read the last converted value
* to clear EOC status and not get a possible interrupt later.
* This value is being read by DMA from LCDR anyway
*/
for_each_set_bit(bit, indio_dev->active_scan_mask,
indio_dev->num_channels) {
struct iio_chan_spec const *chan = indio_dev->channels + bit;
if (st->dma_st.dma_chan)
at91_adc_readl(st, chan->address);
}
/* read overflow register to clear possible overflow status */
at91_adc_readl(st, AT91_SAMA5D2_OVER);
return ret;
}
static const struct iio_buffer_setup_ops at91_buffer_setup_ops = {
.postenable = &at91_adc_buffer_postenable,
.predisable = &at91_adc_buffer_predisable,
};
static struct iio_trigger *at91_adc_allocate_trigger(struct iio_dev *indio,
char *trigger_name)
{
struct iio_trigger *trig;
int ret;
trig = devm_iio_trigger_alloc(&indio->dev, "%s-dev%d-%s", indio->name,
indio->id, trigger_name);
if (!trig)
return NULL;
trig->dev.parent = indio->dev.parent;
iio_trigger_set_drvdata(trig, indio);
trig->ops = &at91_adc_trigger_ops;
ret = devm_iio_trigger_register(&indio->dev, trig);
if (ret)
return ERR_PTR(ret);
return trig;
}
static int at91_adc_trigger_init(struct iio_dev *indio)
{
struct at91_adc_state *st = iio_priv(indio);
st->trig = at91_adc_allocate_trigger(indio, st->selected_trig->name);
if (IS_ERR(st->trig)) {
dev_err(&indio->dev,
"could not allocate trigger\n");
return PTR_ERR(st->trig);
}
return 0;
}
static void at91_adc_trigger_handler_nodma(struct iio_dev *indio_dev,
struct iio_poll_func *pf)
{
struct at91_adc_state *st = iio_priv(indio_dev);
int i = 0;
u8 bit;
for_each_set_bit(bit, indio_dev->active_scan_mask,
indio_dev->num_channels) {
struct iio_chan_spec const *chan = indio_dev->channels + bit;
st->buffer[i] = at91_adc_readl(st, chan->address);
i++;
}
iio_push_to_buffers_with_timestamp(indio_dev, st->buffer,
pf->timestamp);
}
static void at91_adc_trigger_handler_dma(struct iio_dev *indio_dev)
{
struct at91_adc_state *st = iio_priv(indio_dev);
int transferred_len = at91_adc_dma_size_done(st);
s64 ns = iio_get_time_ns(indio_dev);
s64 interval;
int sample_index = 0, sample_count, sample_size;
u32 status = at91_adc_readl(st, AT91_SAMA5D2_ISR);
/* if we reached this point, we cannot sample faster */
if (status & AT91_SAMA5D2_IER_GOVRE)
pr_info_ratelimited("%s: conversion overrun detected\n",
indio_dev->name);
sample_size = div_s64(st->dma_st.rx_buf_sz, st->dma_st.watermark);
sample_count = div_s64(transferred_len, sample_size);
/*
* interval between samples is total time since last transfer handling
* divided by the number of samples (total size divided by sample size)
*/
interval = div_s64((ns - st->dma_st.dma_ts), sample_count);
while (transferred_len >= sample_size) {
iio_push_to_buffers_with_timestamp(indio_dev,
(st->dma_st.rx_buf + st->dma_st.buf_idx),
(st->dma_st.dma_ts + interval * sample_index));
/* adjust remaining length */
transferred_len -= sample_size;
/* adjust buffer index */
st->dma_st.buf_idx += sample_size;
/* in case of reaching end of buffer, reset index */
if (st->dma_st.buf_idx >= st->dma_st.rx_buf_sz)
st->dma_st.buf_idx = 0;
sample_index++;
}
/* adjust saved time for next transfer handling */
st->dma_st.dma_ts = iio_get_time_ns(indio_dev);
}
static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct at91_adc_state *st = iio_priv(indio_dev);
if (st->dma_st.dma_chan)
at91_adc_trigger_handler_dma(indio_dev);
else
at91_adc_trigger_handler_nodma(indio_dev, pf);
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
static int at91_adc_buffer_init(struct iio_dev *indio)
{
return devm_iio_triggered_buffer_setup(&indio->dev, indio,
&iio_pollfunc_store_time,
&at91_adc_trigger_handler, &at91_buffer_setup_ops);
}
static unsigned at91_adc_startup_time(unsigned startup_time_min,
unsigned adc_clk_khz)
{
static const unsigned int startup_lookup[] = {
0, 8, 16, 24,
64, 80, 96, 112,
512, 576, 640, 704,
768, 832, 896, 960
};
unsigned ticks_min, i;
/*
* Since the adc frequency is checked before, there is no reason
* to not meet the startup time constraint.
*/
ticks_min = startup_time_min * adc_clk_khz / 1000;
for (i = 0; i < ARRAY_SIZE(startup_lookup); i++)
if (startup_lookup[i] > ticks_min)
break;
return i;
}
static void at91_adc_setup_samp_freq(struct at91_adc_state *st, unsigned freq)
{
struct iio_dev *indio_dev = iio_priv_to_dev(st);
unsigned f_per, prescal, startup, mr;
f_per = clk_get_rate(st->per_clk);
prescal = (f_per / (2 * freq)) - 1;
startup = at91_adc_startup_time(st->soc_info.startup_time,
freq / 1000);
mr = at91_adc_readl(st, AT91_SAMA5D2_MR);
mr &= ~(AT91_SAMA5D2_MR_STARTUP_MASK | AT91_SAMA5D2_MR_PRESCAL_MASK);
mr |= AT91_SAMA5D2_MR_STARTUP(startup);
mr |= AT91_SAMA5D2_MR_PRESCAL(prescal);
at91_adc_writel(st, AT91_SAMA5D2_MR, mr);
dev_dbg(&indio_dev->dev, "freq: %u, startup: %u, prescal: %u\n",
freq, startup, prescal);
}
static unsigned at91_adc_get_sample_freq(struct at91_adc_state *st)
{
unsigned f_adc, f_per = clk_get_rate(st->per_clk);
unsigned mr, prescal;
mr = at91_adc_readl(st, AT91_SAMA5D2_MR);
prescal = (mr >> AT91_SAMA5D2_MR_PRESCAL_OFFSET)
& AT91_SAMA5D2_MR_PRESCAL_MAX;
f_adc = f_per / (2 * (prescal + 1));
return f_adc;
}
static irqreturn_t at91_adc_interrupt(int irq, void *private)
{
struct iio_dev *indio = private;
struct at91_adc_state *st = iio_priv(indio);
u32 status = at91_adc_readl(st, AT91_SAMA5D2_ISR);
u32 imr = at91_adc_readl(st, AT91_SAMA5D2_IMR);
if (!(status & imr))
return IRQ_NONE;
if (iio_buffer_enabled(indio) && !st->dma_st.dma_chan) {
disable_irq_nosync(irq);
iio_trigger_poll(indio->trig);
} else if (iio_buffer_enabled(indio) && st->dma_st.dma_chan) {
disable_irq_nosync(irq);
WARN(true, "Unexpected irq occurred\n");
} else if (!iio_buffer_enabled(indio)) {
st->conversion_value = at91_adc_readl(st, st->chan->address);
st->conversion_done = true;
wake_up_interruptible(&st->wq_data_available);
}
return IRQ_HANDLED;
}
static int at91_adc_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct at91_adc_state *st = iio_priv(indio_dev);
u32 cor = 0;
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
/* we cannot use software trigger if hw trigger enabled */
ret = iio_device_claim_direct_mode(indio_dev);
if (ret)
return ret;
mutex_lock(&st->lock);
st->chan = chan;
if (chan->differential)
cor = (BIT(chan->channel) | BIT(chan->channel2)) <<
AT91_SAMA5D2_COR_DIFF_OFFSET;
at91_adc_writel(st, AT91_SAMA5D2_COR, cor);
at91_adc_writel(st, AT91_SAMA5D2_CHER, BIT(chan->channel));
at91_adc_writel(st, AT91_SAMA5D2_IER, BIT(chan->channel));
at91_adc_writel(st, AT91_SAMA5D2_CR, AT91_SAMA5D2_CR_START);
ret = wait_event_interruptible_timeout(st->wq_data_available,
st->conversion_done,
msecs_to_jiffies(1000));
if (ret == 0)
ret = -ETIMEDOUT;
if (ret > 0) {
*val = st->conversion_value;
if (chan->scan_type.sign == 's')
*val = sign_extend32(*val, 11);
ret = IIO_VAL_INT;
st->conversion_done = false;
}
at91_adc_writel(st, AT91_SAMA5D2_IDR, BIT(chan->channel));
at91_adc_writel(st, AT91_SAMA5D2_CHDR, BIT(chan->channel));
/* Needed to ACK the DRDY interruption */
at91_adc_readl(st, AT91_SAMA5D2_LCDR);
mutex_unlock(&st->lock);
iio_device_release_direct_mode(indio_dev);
return ret;
case IIO_CHAN_INFO_SCALE:
*val = st->vref_uv / 1000;
if (chan->differential)
*val *= 2;
*val2 = chan->scan_type.realbits;
return IIO_VAL_FRACTIONAL_LOG2;
case IIO_CHAN_INFO_SAMP_FREQ:
*val = at91_adc_get_sample_freq(st);
return IIO_VAL_INT;
default:
return -EINVAL;
}
}
static int at91_adc_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long mask)
{
struct at91_adc_state *st = iio_priv(indio_dev);
if (mask != IIO_CHAN_INFO_SAMP_FREQ)
return -EINVAL;
if (val < st->soc_info.min_sample_rate ||
val > st->soc_info.max_sample_rate)
return -EINVAL;
at91_adc_setup_samp_freq(st, val);
return 0;
}
static void at91_adc_dma_init(struct platform_device *pdev)
{
struct iio_dev *indio_dev = platform_get_drvdata(pdev);
struct at91_adc_state *st = iio_priv(indio_dev);
struct dma_slave_config config = {0};
/*
* We make the buffer double the size of the fifo,
* such that DMA uses one half of the buffer (full fifo size)
* and the software uses the other half to read/write.
*/
unsigned int pages = DIV_ROUND_UP(AT91_HWFIFO_MAX_SIZE *
AT91_BUFFER_MAX_CONVERSION_BYTES * 2,
PAGE_SIZE);
if (st->dma_st.dma_chan)
return;
st->dma_st.dma_chan = dma_request_slave_channel(&pdev->dev, "rx");
if (!st->dma_st.dma_chan) {
dev_info(&pdev->dev, "can't get DMA channel\n");
goto dma_exit;
}
st->dma_st.rx_buf = dma_alloc_coherent(st->dma_st.dma_chan->device->dev,
pages * PAGE_SIZE,
&st->dma_st.rx_dma_buf,
GFP_KERNEL);
if (!st->dma_st.rx_buf) {
dev_info(&pdev->dev, "can't allocate coherent DMA area\n");
goto dma_chan_disable;
}
/* Configure DMA channel to read data register */
config.direction = DMA_DEV_TO_MEM;
config.src_addr = (phys_addr_t)(st->dma_st.phys_addr
+ AT91_SAMA5D2_LCDR);
config.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
config.src_maxburst = 1;
config.dst_maxburst = 1;
if (dmaengine_slave_config(st->dma_st.dma_chan, &config)) {
dev_info(&pdev->dev, "can't configure DMA slave\n");
goto dma_free_area;
}
dev_info(&pdev->dev, "using %s for rx DMA transfers\n",
dma_chan_name(st->dma_st.dma_chan));
return;
dma_free_area:
dma_free_coherent(st->dma_st.dma_chan->device->dev, pages * PAGE_SIZE,
st->dma_st.rx_buf, st->dma_st.rx_dma_buf);
dma_chan_disable:
dma_release_channel(st->dma_st.dma_chan);
st->dma_st.dma_chan = 0;
dma_exit:
dev_info(&pdev->dev, "continuing without DMA support\n");
}
static void at91_adc_dma_disable(struct platform_device *pdev)
{
struct iio_dev *indio_dev = platform_get_drvdata(pdev);
struct at91_adc_state *st = iio_priv(indio_dev);
unsigned int pages = DIV_ROUND_UP(AT91_HWFIFO_MAX_SIZE *
AT91_BUFFER_MAX_CONVERSION_BYTES * 2,
PAGE_SIZE);
/* if we are not using DMA, just return */
if (!st->dma_st.dma_chan)
return;
/* wait for all transactions to be terminated first*/
dmaengine_terminate_sync(st->dma_st.dma_chan);
dma_free_coherent(st->dma_st.dma_chan->device->dev, pages * PAGE_SIZE,
st->dma_st.rx_buf, st->dma_st.rx_dma_buf);
dma_release_channel(st->dma_st.dma_chan);
st->dma_st.dma_chan = 0;
dev_info(&pdev->dev, "continuing without DMA support\n");
}
static int at91_adc_set_watermark(struct iio_dev *indio_dev, unsigned int val)
{
struct at91_adc_state *st = iio_priv(indio_dev);
if (val > AT91_HWFIFO_MAX_SIZE)
return -EINVAL;
if (!st->selected_trig->hw_trig) {
dev_dbg(&indio_dev->dev, "we need hw trigger for DMA\n");
return 0;
}
dev_dbg(&indio_dev->dev, "new watermark is %u\n", val);
st->dma_st.watermark = val;
/*
* The logic here is: if we have watermark 1, it means we do
* each conversion with it's own IRQ, thus we don't need DMA.
* If the watermark is higher, we do DMA to do all the transfers in bulk
*/
if (val == 1)
at91_adc_dma_disable(to_platform_device(&indio_dev->dev));
else if (val > 1)
at91_adc_dma_init(to_platform_device(&indio_dev->dev));
return 0;
}
static const struct iio_info at91_adc_info = {
.read_raw = &at91_adc_read_raw,
.write_raw = &at91_adc_write_raw,
.hwfifo_set_watermark = &at91_adc_set_watermark,
};
static void at91_adc_hw_init(struct at91_adc_state *st)
{
at91_adc_writel(st, AT91_SAMA5D2_CR, AT91_SAMA5D2_CR_SWRST);
at91_adc_writel(st, AT91_SAMA5D2_IDR, 0xffffffff);
/*
* Transfer field must be set to 2 according to the datasheet and
* allows different analog settings for each channel.
*/
at91_adc_writel(st, AT91_SAMA5D2_MR,
AT91_SAMA5D2_MR_TRANSFER(2) | AT91_SAMA5D2_MR_ANACH);
at91_adc_setup_samp_freq(st, st->soc_info.min_sample_rate);
}
static ssize_t at91_adc_get_fifo_state(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct iio_dev *indio_dev =
platform_get_drvdata(to_platform_device(dev));
struct at91_adc_state *st = iio_priv(indio_dev);
return scnprintf(buf, PAGE_SIZE, "%d\n", !!st->dma_st.dma_chan);
}
static ssize_t at91_adc_get_watermark(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct iio_dev *indio_dev =
platform_get_drvdata(to_platform_device(dev));
struct at91_adc_state *st = iio_priv(indio_dev);
return scnprintf(buf, PAGE_SIZE, "%d\n", st->dma_st.watermark);
}
static IIO_DEVICE_ATTR(hwfifo_enabled, 0444,
at91_adc_get_fifo_state, NULL, 0);
static IIO_DEVICE_ATTR(hwfifo_watermark, 0444,
at91_adc_get_watermark, NULL, 0);
static IIO_CONST_ATTR(hwfifo_watermark_min, "2");
static IIO_CONST_ATTR(hwfifo_watermark_max, AT91_HWFIFO_MAX_SIZE_STR);
static const struct attribute *at91_adc_fifo_attributes[] = {
&iio_const_attr_hwfifo_watermark_min.dev_attr.attr,
&iio_const_attr_hwfifo_watermark_max.dev_attr.attr,
&iio_dev_attr_hwfifo_watermark.dev_attr.attr,
&iio_dev_attr_hwfifo_enabled.dev_attr.attr,
NULL,
};
static int at91_adc_probe(struct platform_device *pdev)
{
struct iio_dev *indio_dev;
struct at91_adc_state *st;
struct resource *res;
int ret, i;
u32 edge_type = IRQ_TYPE_NONE;
indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*st));
if (!indio_dev)
return -ENOMEM;
indio_dev->dev.parent = &pdev->dev;
indio_dev->name = dev_name(&pdev->dev);
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->info = &at91_adc_info;
indio_dev->channels = at91_adc_channels;
indio_dev->num_channels = ARRAY_SIZE(at91_adc_channels);
st = iio_priv(indio_dev);
ret = of_property_read_u32(pdev->dev.of_node,
"atmel,min-sample-rate-hz",
&st->soc_info.min_sample_rate);
if (ret) {
dev_err(&pdev->dev,
"invalid or missing value for atmel,min-sample-rate-hz\n");
return ret;
}
ret = of_property_read_u32(pdev->dev.of_node,
"atmel,max-sample-rate-hz",
&st->soc_info.max_sample_rate);
if (ret) {
dev_err(&pdev->dev,
"invalid or missing value for atmel,max-sample-rate-hz\n");
return ret;
}
ret = of_property_read_u32(pdev->dev.of_node, "atmel,startup-time-ms",
&st->soc_info.startup_time);
if (ret) {
dev_err(&pdev->dev,
"invalid or missing value for atmel,startup-time-ms\n");
return ret;
}
ret = of_property_read_u32(pdev->dev.of_node,
"atmel,trigger-edge-type", &edge_type);
if (ret) {
dev_dbg(&pdev->dev,
"atmel,trigger-edge-type not specified, only software trigger available\n");
}
st->selected_trig = NULL;
/* find the right trigger, or no trigger at all */
for (i = 0; i < AT91_SAMA5D2_HW_TRIG_CNT + 1; i++)
if (at91_adc_trigger_list[i].edge_type == edge_type) {
st->selected_trig = &at91_adc_trigger_list[i];
break;
}
if (!st->selected_trig) {
dev_err(&pdev->dev, "invalid external trigger edge value\n");
return -EINVAL;
}
init_waitqueue_head(&st->wq_data_available);
mutex_init(&st->lock);
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res)
return -EINVAL;
/* if we plan to use DMA, we need the physical address of the regs */
st->dma_st.phys_addr = res->start;
st->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(st->base))
return PTR_ERR(st->base);
st->irq = platform_get_irq(pdev, 0);
if (st->irq <= 0) {
if (!st->irq)
st->irq = -ENXIO;
return st->irq;
}
st->per_clk = devm_clk_get(&pdev->dev, "adc_clk");
if (IS_ERR(st->per_clk))
return PTR_ERR(st->per_clk);
st->reg = devm_regulator_get(&pdev->dev, "vddana");
if (IS_ERR(st->reg))
return PTR_ERR(st->reg);
st->vref = devm_regulator_get(&pdev->dev, "vref");
if (IS_ERR(st->vref))
return PTR_ERR(st->vref);
ret = devm_request_irq(&pdev->dev, st->irq, at91_adc_interrupt, 0,
pdev->dev.driver->name, indio_dev);
if (ret)
return ret;
ret = regulator_enable(st->reg);
if (ret)
return ret;
ret = regulator_enable(st->vref);
if (ret)
goto reg_disable;
st->vref_uv = regulator_get_voltage(st->vref);
if (st->vref_uv <= 0) {
ret = -EINVAL;
goto vref_disable;
}
at91_adc_hw_init(st);
ret = clk_prepare_enable(st->per_clk);
if (ret)
goto vref_disable;
platform_set_drvdata(pdev, indio_dev);
if (st->selected_trig->hw_trig) {
ret = at91_adc_buffer_init(indio_dev);
if (ret < 0) {
dev_err(&pdev->dev, "couldn't initialize the buffer.\n");
goto per_clk_disable_unprepare;
}
ret = at91_adc_trigger_init(indio_dev);
if (ret < 0) {
dev_err(&pdev->dev, "couldn't setup the triggers.\n");
goto per_clk_disable_unprepare;
}
/*
* Initially the iio buffer has a length of 2 and
* a watermark of 1
*/
st->dma_st.watermark = 1;
iio_buffer_set_attrs(indio_dev->buffer,
at91_adc_fifo_attributes);
}
if (dma_coerce_mask_and_coherent(&indio_dev->dev, DMA_BIT_MASK(32)))
dev_info(&pdev->dev, "cannot set DMA mask to 32-bit\n");
ret = iio_device_register(indio_dev);
if (ret < 0)
goto dma_disable;
if (st->selected_trig->hw_trig)
dev_info(&pdev->dev, "setting up trigger as %s\n",
st->selected_trig->name);
dev_info(&pdev->dev, "version: %x\n",
readl_relaxed(st->base + AT91_SAMA5D2_VERSION));
return 0;
dma_disable:
at91_adc_dma_disable(pdev);
per_clk_disable_unprepare:
clk_disable_unprepare(st->per_clk);
vref_disable:
regulator_disable(st->vref);
reg_disable:
regulator_disable(st->reg);
return ret;
}
static int at91_adc_remove(struct platform_device *pdev)
{
struct iio_dev *indio_dev = platform_get_drvdata(pdev);
struct at91_adc_state *st = iio_priv(indio_dev);
iio_device_unregister(indio_dev);
at91_adc_dma_disable(pdev);
clk_disable_unprepare(st->per_clk);
regulator_disable(st->vref);
regulator_disable(st->reg);
return 0;
}
static __maybe_unused int at91_adc_suspend(struct device *dev)
{
struct iio_dev *indio_dev =
platform_get_drvdata(to_platform_device(dev));
struct at91_adc_state *st = iio_priv(indio_dev);
/*
* Do a sofware reset of the ADC before we go to suspend.
* this will ensure that all pins are free from being muxed by the ADC
* and can be used by for other devices.
* Otherwise, ADC will hog them and we can't go to suspend mode.
*/
at91_adc_writel(st, AT91_SAMA5D2_CR, AT91_SAMA5D2_CR_SWRST);
clk_disable_unprepare(st->per_clk);
regulator_disable(st->vref);
regulator_disable(st->reg);
return pinctrl_pm_select_sleep_state(dev);
}
static __maybe_unused int at91_adc_resume(struct device *dev)
{
struct iio_dev *indio_dev =
platform_get_drvdata(to_platform_device(dev));
struct at91_adc_state *st = iio_priv(indio_dev);
int ret;
ret = pinctrl_pm_select_default_state(dev);
if (ret)
goto resume_failed;
ret = regulator_enable(st->reg);
if (ret)
goto resume_failed;
ret = regulator_enable(st->vref);
if (ret)
goto reg_disable_resume;
ret = clk_prepare_enable(st->per_clk);
if (ret)
goto vref_disable_resume;
at91_adc_hw_init(st);
/* reconfiguring trigger hardware state */
if (iio_buffer_enabled(indio_dev))
at91_adc_configure_trigger(st->trig, true);
return 0;
vref_disable_resume:
regulator_disable(st->vref);
reg_disable_resume:
regulator_disable(st->reg);
resume_failed:
dev_err(&indio_dev->dev, "failed to resume\n");
return ret;
}
static SIMPLE_DEV_PM_OPS(at91_adc_pm_ops, at91_adc_suspend, at91_adc_resume);
static const struct of_device_id at91_adc_dt_match[] = {
{
.compatible = "atmel,sama5d2-adc",
}, {
/* sentinel */
}
};
MODULE_DEVICE_TABLE(of, at91_adc_dt_match);
static struct platform_driver at91_adc_driver = {
.probe = at91_adc_probe,
.remove = at91_adc_remove,
.driver = {
.name = "at91-sama5d2_adc",
.of_match_table = at91_adc_dt_match,
.pm = &at91_adc_pm_ops,
},
};
module_platform_driver(at91_adc_driver)
MODULE_AUTHOR("Ludovic Desroches <ludovic.desroches@atmel.com>");
MODULE_DESCRIPTION("Atmel AT91 SAMA5D2 ADC");
MODULE_LICENSE("GPL v2");
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