- 根目录:
- drivers
- iio
- adc
- at91_adc.c
/*
* 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/of.h>
#include <linux/of_device.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/trigger.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.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;
u16 last_value;
struct mutex lock;
u8 num_channels;
void __iomem *reg_base;
struct at91_adc_reg_desc *registers;
u8 startup_time;
u8 sample_hold_time;
bool sleep_mode;
struct iio_trigger **trig;
struct at91_adc_trigger *trigger_list;
u32 trigger_number;
bool use_external;
u32 vref_mv;
u32 res; /* resolution used for convertions */
bool low_res; /* the resolution corresponds to the lowest one */
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);
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;
}
iio_push_to_buffers(idev, (u8 *)st->buffer);
iio_trigger_notify_done(idev->trig);
/* 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);
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 = st->res;
chan->scan_type.storagebits = 16;
chan->info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE);
chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
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 = iio_trigger_get_drvdata(trig);
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;
iio_trigger_set_drvdata(trig, 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 int at91_adc_buffer_init(struct iio_dev *idev)
{
return iio_triggered_buffer_setup(idev, &iio_pollfunc_store_time,
&at91_adc_trigger_handler, NULL);
}
static void at91_adc_buffer_remove(struct iio_dev *idev)
{
iio_triggered_buffer_cleanup(idev);
}
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)
ret = -ETIMEDOUT;
if (ret < 0) {
mutex_unlock(&st->lock);
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_of_get_resolution(struct at91_adc_state *st,
struct platform_device *pdev)
{
struct iio_dev *idev = iio_priv_to_dev(st);
struct device_node *np = pdev->dev.of_node;
int count, i, ret = 0;
char *res_name, *s;
u32 *resolutions;
count = of_property_count_strings(np, "atmel,adc-res-names");
if (count < 2) {
dev_err(&idev->dev, "You must specified at least two resolution names for "
"adc-res-names property in the DT\n");
return count;
}
resolutions = kmalloc(count * sizeof(*resolutions), GFP_KERNEL);
if (!resolutions)
return -ENOMEM;
if (of_property_read_u32_array(np, "atmel,adc-res", resolutions, count)) {
dev_err(&idev->dev, "Missing adc-res property in the DT.\n");
ret = -ENODEV;
goto ret;
}
if (of_property_read_string(np, "atmel,adc-use-res", (const char **)&res_name))
res_name = "highres";
for (i = 0; i < count; i++) {
if (of_property_read_string_index(np, "atmel,adc-res-names", i, (const char **)&s))
continue;
if (strcmp(res_name, s))
continue;
st->res = resolutions[i];
if (!strcmp(res_name, "lowres"))
st->low_res = true;
else
st->low_res = false;
dev_info(&idev->dev, "Resolution used: %u bits\n", st->res);
goto ret;
}
dev_err(&idev->dev, "There is no resolution for %s\n", res_name);
ret:
kfree(resolutions);
return ret;
}
static int at91_adc_probe_dt(struct at91_adc_state *st,
struct platform_device *pdev)
{
struct iio_dev *idev = iio_priv_to_dev(st);
struct device_node *node = pdev->dev.of_node;
struct device_node *trig_node;
int i = 0, ret;
u32 prop;
if (!node)
return -EINVAL;
st->use_external = of_property_read_bool(node, "atmel,adc-use-external-triggers");
if (of_property_read_u32(node, "atmel,adc-channels-used", &prop)) {
dev_err(&idev->dev, "Missing adc-channels-used property in the DT.\n");
ret = -EINVAL;
goto error_ret;
}
st->channels_mask = prop;
if (of_property_read_u32(node, "atmel,adc-num-channels", &prop)) {
dev_err(&idev->dev, "Missing adc-num-channels property in the DT.\n");
ret = -EINVAL;
goto error_ret;
}
st->num_channels = prop;
st->sleep_mode = of_property_read_bool(node, "atmel,adc-sleep-mode");
if (of_property_read_u32(node, "atmel,adc-startup-time", &prop)) {
dev_err(&idev->dev, "Missing adc-startup-time property in the DT.\n");
ret = -EINVAL;
goto error_ret;
}
st->startup_time = prop;
prop = 0;
of_property_read_u32(node, "atmel,adc-sample-hold-time", &prop);
st->sample_hold_time = prop;
if (of_property_read_u32(node, "atmel,adc-vref", &prop)) {
dev_err(&idev->dev, "Missing adc-vref property in the DT.\n");
ret = -EINVAL;
goto error_ret;
}
st->vref_mv = prop;
ret = at91_adc_of_get_resolution(st, pdev);
if (ret)
goto error_ret;
st->registers = devm_kzalloc(&idev->dev,
sizeof(struct at91_adc_reg_desc),
GFP_KERNEL);
if (!st->registers) {
dev_err(&idev->dev, "Could not allocate register memory.\n");
ret = -ENOMEM;
goto error_ret;
}
if (of_property_read_u32(node, "atmel,adc-channel-base", &prop)) {
dev_err(&idev->dev, "Missing adc-channel-base property in the DT.\n");
ret = -EINVAL;
goto error_ret;
}
st->registers->channel_base = prop;
if (of_property_read_u32(node, "atmel,adc-drdy-mask", &prop)) {
dev_err(&idev->dev, "Missing adc-drdy-mask property in the DT.\n");
ret = -EINVAL;
goto error_ret;
}
st->registers->drdy_mask = prop;
if (of_property_read_u32(node, "atmel,adc-status-register", &prop)) {
dev_err(&idev->dev, "Missing adc-status-register property in the DT.\n");
ret = -EINVAL;
goto error_ret;
}
st->registers->status_register = prop;
if (of_property_read_u32(node, "atmel,adc-trigger-register", &prop)) {
dev_err(&idev->dev, "Missing adc-trigger-register property in the DT.\n");
ret = -EINVAL;
goto error_ret;
}
st->registers->trigger_register = prop;
st->trigger_number = of_get_child_count(node);
st->trigger_list = devm_kzalloc(&idev->dev, st->trigger_number *
sizeof(struct at91_adc_trigger),
GFP_KERNEL);
if (!st->trigger_list) {
dev_err(&idev->dev, "Could not allocate trigger list memory.\n");
ret = -ENOMEM;
goto error_ret;
}
for_each_child_of_node(node, trig_node) {
struct at91_adc_trigger *trig = st->trigger_list + i;
const char *name;
if (of_property_read_string(trig_node, "trigger-name", &name)) {
dev_err(&idev->dev, "Missing trigger-name property in the DT.\n");
ret = -EINVAL;
goto error_ret;
}
trig->name = name;
if (of_property_read_u32(trig_node, "trigger-value", &prop)) {
dev_err(&idev->dev, "Missing trigger-value property in the DT.\n");
ret = -EINVAL;
goto error_ret;
}
trig->value = prop;
trig->is_external = of_property_read_bool(trig_node, "trigger-external");
i++;
}
return 0;
error_ret:
return ret;
}
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 at91_adc_probe(struct platform_device *pdev)
{
unsigned int prsc, mstrclk, ticks, adc_clk, shtim;
int ret;
struct iio_dev *idev;
struct at91_adc_state *st;
struct resource *res;
u32 reg;
idev = iio_device_alloc(sizeof(struct at91_adc_state));
if (idev == NULL) {
ret = -ENOMEM;
goto error_ret;
}
st = iio_priv(idev);
if (pdev->dev.of_node)
ret = at91_adc_probe_dt(st, pdev);
else
ret = at91_adc_probe_pdata(st, pdev);
if (ret) {
dev_err(&pdev->dev, "No platform data available.\n");
ret = -EINVAL;
goto error_free_device;
}
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;
}
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
st->reg_base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(st->reg_base)) {
ret = PTR_ERR(st->reg_base);
goto error_free_device;
}
/*
* 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_free_device;
}
st->clk = devm_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_enable(st->clk);
if (ret) {
dev_err(&pdev->dev,
"Could not prepare or enable the clock.\n");
goto error_free_irq;
}
st->adc_clk = devm_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->adc_clk);
goto error_disable_clk;
}
ret = clk_prepare_enable(st->adc_clk);
if (ret) {
dev_err(&pdev->dev,
"Could not prepare or enable the ADC clock.\n");
goto error_disable_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;
/*
* a minimal Sample and Hold Time is necessary for the ADC to guarantee
* the best converted final value between two channels selection
* The formula thus is : Sample and Hold Time = (shtim + 1) / ADCClock
*/
shtim = round_up((st->sample_hold_time * adc_clk /
1000000) - 1, 1);
reg = AT91_ADC_PRESCAL_(prsc) & AT91_ADC_PRESCAL;
reg |= AT91_ADC_STARTUP_(ticks) & AT91_ADC_STARTUP;
if (st->low_res)
reg |= AT91_ADC_LOWRES;
if (st->sleep_mode)
reg |= AT91_ADC_SLEEP;
reg |= AT91_ADC_SHTIM_(shtim) & AT91_ADC_SHTIM;
at91_adc_writel(st, AT91_ADC_MR, reg);
/* 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_unprepare(st->adc_clk);
error_disable_clk:
clk_disable_unprepare(st->clk);
error_free_irq:
free_irq(st->irq, idev);
error_free_device:
iio_device_free(idev);
error_ret:
return ret;
}
static int at91_adc_remove(struct platform_device *pdev)
{
struct iio_dev *idev = platform_get_drvdata(pdev);
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_disable_unprepare(st->clk);
free_irq(st->irq, idev);
iio_device_free(idev);
return 0;
}
static const struct of_device_id at91_adc_dt_ids[] = {
{ .compatible = "atmel,at91sam9260-adc" },
{},
};
MODULE_DEVICE_TABLE(of, at91_adc_dt_ids);
static struct platform_driver at91_adc_driver = {
.probe = at91_adc_probe,
.remove = at91_adc_remove,
.driver = {
.name = "at91_adc",
.of_match_table = of_match_ptr(at91_adc_dt_ids),
},
};
module_platform_driver(at91_adc_driver);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Atmel AT91 ADC Driver");
MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");