ARM: AT91: IIO: Add AT91 ADC driver.

Add the ADC driver for Atmel's AT91SAM9G20-EK, AT91SAM9M10G45-EK
and AT91SAM9X5 family boards.

It has support for both software and hardware triggers.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Maxime Ripard 2012-05-11 15:35:33 +02:00 committed by Greg Kroah-Hartman
parent aaeb6dfff0
commit 0e589d5fb3
5 changed files with 695 additions and 0 deletions

View file

@ -48,6 +48,7 @@ config IIO_CONSUMERS_PER_TRIGGER
This value controls the maximum number of consumers that a
given trigger may handle. Default is 2.
source "drivers/iio/adc/Kconfig"
source "drivers/iio/amplifiers/Kconfig"
endif # IIO

View file

@ -9,4 +9,5 @@ industrialio-$(CONFIG_IIO_TRIGGER) += industrialio-trigger.o
obj-$(CONFIG_IIO_KFIFO_BUF) += kfifo_buf.o
obj-y += adc/
obj-y += amplifiers/

16
drivers/iio/adc/Kconfig Normal file
View file

@ -0,0 +1,16 @@
#
# ADC drivers
#
menu "Analog to digital converters"
config AT91_ADC
tristate "Atmel AT91 ADC"
depends on ARCH_AT91
select IIO_BUFFER
select IIO_KFIFO_BUF
select IIO_TRIGGER
select SYSFS
help
Say yes here to build support for Atmel AT91 ADC.
endmenu

5
drivers/iio/adc/Makefile Normal file
View file

@ -0,0 +1,5 @@
#
# Makefile for IIO ADC drivers
#
obj-$(CONFIG_AT91_ADC) += at91_adc.o

672
drivers/iio/adc/at91_adc.c Normal file
View file

@ -0,0 +1,672 @@
/*
* Driver for the ADC present in the Atmel AT91 evaluation boards.
*
* Copyright 2011 Free Electrons
*
* Licensed under the GPLv2 or later.
*/
#include <linux/bitmap.h>
#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/interrupt.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/wait.h>
#include <linux/platform_data/at91_adc.h>
#include <linux/iio/iio.h>
#include <linux/iio/buffer.h>
#include <linux/iio/kfifo_buf.h>
#include <linux/iio/trigger.h>
#include <linux/iio/trigger_consumer.h>
#include <mach/at91_adc.h>
#define AT91_ADC_CHAN(st, ch) \
(st->registers->channel_base + (ch * 4))
#define at91_adc_readl(st, reg) \
(readl_relaxed(st->reg_base + reg))
#define at91_adc_writel(st, reg, val) \
(writel_relaxed(val, st->reg_base + reg))
struct at91_adc_state {
struct clk *adc_clk;
u16 *buffer;
unsigned long channels_mask;
struct clk *clk;
bool done;
int irq;
bool irq_enabled;
u16 last_value;
struct mutex lock;
u8 num_channels;
void __iomem *reg_base;
struct at91_adc_reg_desc *registers;
u8 startup_time;
struct iio_trigger **trig;
struct at91_adc_trigger *trigger_list;
u32 trigger_number;
bool use_external;
u32 vref_mv;
wait_queue_head_t wq_data_avail;
};
static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *idev = pf->indio_dev;
struct at91_adc_state *st = iio_priv(idev);
struct iio_buffer *buffer = idev->buffer;
int i, j = 0;
for (i = 0; i < idev->masklength; i++) {
if (!test_bit(i, idev->active_scan_mask))
continue;
st->buffer[j] = at91_adc_readl(st, AT91_ADC_CHAN(st, i));
j++;
}
if (idev->scan_timestamp) {
s64 *timestamp = (s64 *)((u8 *)st->buffer +
ALIGN(j, sizeof(s64)));
*timestamp = pf->timestamp;
}
buffer->access->store_to(buffer, (u8 *)st->buffer, pf->timestamp);
iio_trigger_notify_done(idev->trig);
st->irq_enabled = true;
/* Needed to ACK the DRDY interruption */
at91_adc_readl(st, AT91_ADC_LCDR);
enable_irq(st->irq);
return IRQ_HANDLED;
}
static irqreturn_t at91_adc_eoc_trigger(int irq, void *private)
{
struct iio_dev *idev = private;
struct at91_adc_state *st = iio_priv(idev);
u32 status = at91_adc_readl(st, st->registers->status_register);
if (!(status & st->registers->drdy_mask))
return IRQ_HANDLED;
if (iio_buffer_enabled(idev)) {
disable_irq_nosync(irq);
st->irq_enabled = false;
iio_trigger_poll(idev->trig, iio_get_time_ns());
} else {
st->last_value = at91_adc_readl(st, AT91_ADC_LCDR);
st->done = true;
wake_up_interruptible(&st->wq_data_avail);
}
return IRQ_HANDLED;
}
static int at91_adc_channel_init(struct iio_dev *idev)
{
struct at91_adc_state *st = iio_priv(idev);
struct iio_chan_spec *chan_array, *timestamp;
int bit, idx = 0;
idev->num_channels = bitmap_weight(&st->channels_mask,
st->num_channels) + 1;
chan_array = devm_kzalloc(&idev->dev,
((idev->num_channels + 1) *
sizeof(struct iio_chan_spec)),
GFP_KERNEL);
if (!chan_array)
return -ENOMEM;
for_each_set_bit(bit, &st->channels_mask, st->num_channels) {
struct iio_chan_spec *chan = chan_array + idx;
chan->type = IIO_VOLTAGE;
chan->indexed = 1;
chan->channel = bit;
chan->scan_index = idx;
chan->scan_type.sign = 'u';
chan->scan_type.realbits = 10;
chan->scan_type.storagebits = 16;
chan->info_mask = IIO_CHAN_INFO_SCALE_SHARED_BIT |
IIO_CHAN_INFO_RAW_SEPARATE_BIT;
idx++;
}
timestamp = chan_array + idx;
timestamp->type = IIO_TIMESTAMP;
timestamp->channel = -1;
timestamp->scan_index = idx;
timestamp->scan_type.sign = 's';
timestamp->scan_type.realbits = 64;
timestamp->scan_type.storagebits = 64;
idev->channels = chan_array;
return idev->num_channels;
}
static u8 at91_adc_get_trigger_value_by_name(struct iio_dev *idev,
struct at91_adc_trigger *triggers,
const char *trigger_name)
{
struct at91_adc_state *st = iio_priv(idev);
u8 value = 0;
int i;
for (i = 0; i < st->trigger_number; i++) {
char *name = kasprintf(GFP_KERNEL,
"%s-dev%d-%s",
idev->name,
idev->id,
triggers[i].name);
if (!name)
return -ENOMEM;
if (strcmp(trigger_name, name) == 0) {
value = triggers[i].value;
kfree(name);
break;
}
kfree(name);
}
return value;
}
static int at91_adc_configure_trigger(struct iio_trigger *trig, bool state)
{
struct iio_dev *idev = trig->private_data;
struct at91_adc_state *st = iio_priv(idev);
struct iio_buffer *buffer = idev->buffer;
struct at91_adc_reg_desc *reg = st->registers;
u32 status = at91_adc_readl(st, reg->trigger_register);
u8 value;
u8 bit;
value = at91_adc_get_trigger_value_by_name(idev,
st->trigger_list,
idev->trig->name);
if (value == 0)
return -EINVAL;
if (state) {
st->buffer = kmalloc(idev->scan_bytes, GFP_KERNEL);
if (st->buffer == NULL)
return -ENOMEM;
at91_adc_writel(st, reg->trigger_register,
status | value);
for_each_set_bit(bit, buffer->scan_mask,
st->num_channels) {
struct iio_chan_spec const *chan = idev->channels + bit;
at91_adc_writel(st, AT91_ADC_CHER,
AT91_ADC_CH(chan->channel));
}
at91_adc_writel(st, AT91_ADC_IER, reg->drdy_mask);
} else {
at91_adc_writel(st, AT91_ADC_IDR, reg->drdy_mask);
at91_adc_writel(st, reg->trigger_register,
status & ~value);
for_each_set_bit(bit, buffer->scan_mask,
st->num_channels) {
struct iio_chan_spec const *chan = idev->channels + bit;
at91_adc_writel(st, AT91_ADC_CHDR,
AT91_ADC_CH(chan->channel));
}
kfree(st->buffer);
}
return 0;
}
static const struct iio_trigger_ops at91_adc_trigger_ops = {
.owner = THIS_MODULE,
.set_trigger_state = &at91_adc_configure_trigger,
};
static struct iio_trigger *at91_adc_allocate_trigger(struct iio_dev *idev,
struct at91_adc_trigger *trigger)
{
struct iio_trigger *trig;
int ret;
trig = iio_trigger_alloc("%s-dev%d-%s", idev->name,
idev->id, trigger->name);
if (trig == NULL)
return NULL;
trig->dev.parent = idev->dev.parent;
trig->private_data = idev;
trig->ops = &at91_adc_trigger_ops;
ret = iio_trigger_register(trig);
if (ret)
return NULL;
return trig;
}
static int at91_adc_trigger_init(struct iio_dev *idev)
{
struct at91_adc_state *st = iio_priv(idev);
int i, ret;
st->trig = devm_kzalloc(&idev->dev,
st->trigger_number * sizeof(st->trig),
GFP_KERNEL);
if (st->trig == NULL) {
ret = -ENOMEM;
goto error_ret;
}
for (i = 0; i < st->trigger_number; i++) {
if (st->trigger_list[i].is_external && !(st->use_external))
continue;
st->trig[i] = at91_adc_allocate_trigger(idev,
st->trigger_list + i);
if (st->trig[i] == NULL) {
dev_err(&idev->dev,
"Could not allocate trigger %d\n", i);
ret = -ENOMEM;
goto error_trigger;
}
}
return 0;
error_trigger:
for (i--; i >= 0; i--) {
iio_trigger_unregister(st->trig[i]);
iio_trigger_free(st->trig[i]);
}
error_ret:
return ret;
}
static void at91_adc_trigger_remove(struct iio_dev *idev)
{
struct at91_adc_state *st = iio_priv(idev);
int i;
for (i = 0; i < st->trigger_number; i++) {
iio_trigger_unregister(st->trig[i]);
iio_trigger_free(st->trig[i]);
}
}
static const struct iio_buffer_setup_ops at91_adc_buffer_ops = {
.preenable = &iio_sw_buffer_preenable,
.postenable = &iio_triggered_buffer_postenable,
.predisable = &iio_triggered_buffer_predisable,
};
static int at91_adc_buffer_init(struct iio_dev *idev)
{
int ret;
idev->buffer = iio_kfifo_allocate(idev);
if (!idev->buffer) {
ret = -ENOMEM;
goto error_ret;
}
idev->pollfunc = iio_alloc_pollfunc(&iio_pollfunc_store_time,
&at91_adc_trigger_handler,
IRQF_ONESHOT,
idev,
"%s-consumer%d",
idev->name,
idev->id);
if (idev->pollfunc == NULL) {
ret = -ENOMEM;
goto error_pollfunc;
}
idev->setup_ops = &at91_adc_buffer_ops;
idev->modes |= INDIO_BUFFER_TRIGGERED;
ret = iio_buffer_register(idev,
idev->channels,
idev->num_channels);
if (ret)
goto error_register;
return 0;
error_register:
iio_dealloc_pollfunc(idev->pollfunc);
error_pollfunc:
iio_kfifo_free(idev->buffer);
error_ret:
return ret;
}
static void at91_adc_buffer_remove(struct iio_dev *idev)
{
iio_buffer_unregister(idev);
iio_dealloc_pollfunc(idev->pollfunc);
iio_kfifo_free(idev->buffer);
}
static int at91_adc_read_raw(struct iio_dev *idev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct at91_adc_state *st = iio_priv(idev);
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
mutex_lock(&st->lock);
at91_adc_writel(st, AT91_ADC_CHER,
AT91_ADC_CH(chan->channel));
at91_adc_writel(st, AT91_ADC_IER, st->registers->drdy_mask);
at91_adc_writel(st, AT91_ADC_CR, AT91_ADC_START);
ret = wait_event_interruptible_timeout(st->wq_data_avail,
st->done,
msecs_to_jiffies(1000));
if (ret == 0)
return -ETIMEDOUT;
else if (ret < 0)
return ret;
*val = st->last_value;
at91_adc_writel(st, AT91_ADC_CHDR,
AT91_ADC_CH(chan->channel));
at91_adc_writel(st, AT91_ADC_IDR, st->registers->drdy_mask);
st->last_value = 0;
st->done = false;
mutex_unlock(&st->lock);
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
*val = (st->vref_mv * 1000) >> chan->scan_type.realbits;
*val2 = 0;
return IIO_VAL_INT_PLUS_MICRO;
default:
break;
}
return -EINVAL;
}
static int at91_adc_probe_pdata(struct at91_adc_state *st,
struct platform_device *pdev)
{
struct at91_adc_data *pdata = pdev->dev.platform_data;
if (!pdata)
return -EINVAL;
st->use_external = pdata->use_external_triggers;
st->vref_mv = pdata->vref;
st->channels_mask = pdata->channels_used;
st->num_channels = pdata->num_channels;
st->startup_time = pdata->startup_time;
st->trigger_number = pdata->trigger_number;
st->trigger_list = pdata->trigger_list;
st->registers = pdata->registers;
return 0;
}
static const struct iio_info at91_adc_info = {
.driver_module = THIS_MODULE,
.read_raw = &at91_adc_read_raw,
};
static int __devinit at91_adc_probe(struct platform_device *pdev)
{
unsigned int prsc, mstrclk, ticks, adc_clk;
int ret;
struct iio_dev *idev;
struct at91_adc_state *st;
struct resource *res;
idev = iio_device_alloc(sizeof(struct at91_adc_state));
if (idev == NULL) {
ret = -ENOMEM;
goto error_ret;
}
st = iio_priv(idev);
ret = at91_adc_probe_pdata(st, pdev);
if (ret) {
dev_err(&pdev->dev, "No platform data available.\n");
ret = -EINVAL;
goto error_free_device;
}
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res) {
dev_err(&pdev->dev, "No resource defined\n");
ret = -ENXIO;
goto error_ret;
}
platform_set_drvdata(pdev, idev);
idev->dev.parent = &pdev->dev;
idev->name = dev_name(&pdev->dev);
idev->modes = INDIO_DIRECT_MODE;
idev->info = &at91_adc_info;
st->irq = platform_get_irq(pdev, 0);
if (st->irq < 0) {
dev_err(&pdev->dev, "No IRQ ID is designated\n");
ret = -ENODEV;
goto error_free_device;
}
if (!request_mem_region(res->start, resource_size(res),
"AT91 adc registers")) {
dev_err(&pdev->dev, "Resources are unavailable.\n");
ret = -EBUSY;
goto error_free_device;
}
st->reg_base = ioremap(res->start, resource_size(res));
if (!st->reg_base) {
dev_err(&pdev->dev, "Failed to map registers.\n");
ret = -ENOMEM;
goto error_release_mem;
}
/*
* Disable all IRQs before setting up the handler
*/
at91_adc_writel(st, AT91_ADC_CR, AT91_ADC_SWRST);
at91_adc_writel(st, AT91_ADC_IDR, 0xFFFFFFFF);
ret = request_irq(st->irq,
at91_adc_eoc_trigger,
0,
pdev->dev.driver->name,
idev);
if (ret) {
dev_err(&pdev->dev, "Failed to allocate IRQ.\n");
goto error_unmap_reg;
}
st->clk = clk_get(&pdev->dev, "adc_clk");
if (IS_ERR(st->clk)) {
dev_err(&pdev->dev, "Failed to get the clock.\n");
ret = PTR_ERR(st->clk);
goto error_free_irq;
}
ret = clk_prepare(st->clk);
if (ret) {
dev_err(&pdev->dev, "Could not prepare the clock.\n");
goto error_free_clk;
}
ret = clk_enable(st->clk);
if (ret) {
dev_err(&pdev->dev, "Could not enable the clock.\n");
goto error_unprepare_clk;
}
st->adc_clk = clk_get(&pdev->dev, "adc_op_clk");
if (IS_ERR(st->adc_clk)) {
dev_err(&pdev->dev, "Failed to get the ADC clock.\n");
ret = PTR_ERR(st->clk);
goto error_disable_clk;
}
ret = clk_prepare(st->adc_clk);
if (ret) {
dev_err(&pdev->dev, "Could not prepare the ADC clock.\n");
goto error_free_adc_clk;
}
ret = clk_enable(st->adc_clk);
if (ret) {
dev_err(&pdev->dev, "Could not enable the ADC clock.\n");
goto error_unprepare_adc_clk;
}
/*
* Prescaler rate computation using the formula from the Atmel's
* datasheet : ADC Clock = MCK / ((Prescaler + 1) * 2), ADC Clock being
* specified by the electrical characteristics of the board.
*/
mstrclk = clk_get_rate(st->clk);
adc_clk = clk_get_rate(st->adc_clk);
prsc = (mstrclk / (2 * adc_clk)) - 1;
if (!st->startup_time) {
dev_err(&pdev->dev, "No startup time available.\n");
ret = -EINVAL;
goto error_disable_adc_clk;
}
/*
* Number of ticks needed to cover the startup time of the ADC as
* defined in the electrical characteristics of the board, divided by 8.
* The formula thus is : Startup Time = (ticks + 1) * 8 / ADC Clock
*/
ticks = round_up((st->startup_time * adc_clk /
1000000) - 1, 8) / 8;
at91_adc_writel(st, AT91_ADC_MR,
(AT91_ADC_PRESCAL_(prsc) & AT91_ADC_PRESCAL) |
(AT91_ADC_STARTUP_(ticks) & AT91_ADC_STARTUP));
/* Setup the ADC channels available on the board */
ret = at91_adc_channel_init(idev);
if (ret < 0) {
dev_err(&pdev->dev, "Couldn't initialize the channels.\n");
goto error_disable_adc_clk;
}
init_waitqueue_head(&st->wq_data_avail);
mutex_init(&st->lock);
ret = at91_adc_buffer_init(idev);
if (ret < 0) {
dev_err(&pdev->dev, "Couldn't initialize the buffer.\n");
goto error_disable_adc_clk;
}
ret = at91_adc_trigger_init(idev);
if (ret < 0) {
dev_err(&pdev->dev, "Couldn't setup the triggers.\n");
goto error_unregister_buffer;
}
ret = iio_device_register(idev);
if (ret < 0) {
dev_err(&pdev->dev, "Couldn't register the device.\n");
goto error_remove_triggers;
}
return 0;
error_remove_triggers:
at91_adc_trigger_remove(idev);
error_unregister_buffer:
at91_adc_buffer_remove(idev);
error_disable_adc_clk:
clk_disable(st->adc_clk);
error_unprepare_adc_clk:
clk_unprepare(st->adc_clk);
error_free_adc_clk:
clk_put(st->adc_clk);
error_disable_clk:
clk_disable(st->clk);
error_unprepare_clk:
clk_unprepare(st->clk);
error_free_clk:
clk_put(st->clk);
error_free_irq:
free_irq(st->irq, idev);
error_unmap_reg:
iounmap(st->reg_base);
error_release_mem:
release_mem_region(res->start, resource_size(res));
error_free_device:
iio_device_free(idev);
error_ret:
return ret;
}
static int __devexit at91_adc_remove(struct platform_device *pdev)
{
struct iio_dev *idev = platform_get_drvdata(pdev);
struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
struct at91_adc_state *st = iio_priv(idev);
iio_device_unregister(idev);
at91_adc_trigger_remove(idev);
at91_adc_buffer_remove(idev);
clk_disable_unprepare(st->adc_clk);
clk_put(st->adc_clk);
clk_disable(st->clk);
clk_unprepare(st->clk);
clk_put(st->clk);
free_irq(st->irq, idev);
iounmap(st->reg_base);
release_mem_region(res->start, resource_size(res));
iio_device_free(idev);
return 0;
}
static struct platform_driver at91_adc_driver = {
.probe = at91_adc_probe,
.remove = __devexit_p(at91_adc_remove),
.driver = {
.name = "at91_adc",
},
};
module_platform_driver(at91_adc_driver);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Atmel AT91 ADC Driver");
MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");