/*
* Freescale i.MX28 LRADC driver
*
* Copyright (c) 2012 DENX Software Engineering, GmbH.
* Marek Vasut <marex@denx.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* 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/err.h>
#include <linux/interrupt.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/sysfs.h>
#include <linux/list.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <linux/wait.h>
#include <linux/sched.h>
#include <linux/stmp_device.h>
#include <linux/bitops.h>
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/input.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>
#define DRIVER_NAME "mxs-lradc"
#define LRADC_MAX_DELAY_CHANS 4
#define LRADC_MAX_MAPPED_CHANS 8
#define LRADC_MAX_TOTAL_CHANS 16
#define LRADC_DELAY_TIMER_HZ 2000
/*
* Make this runtime configurable if necessary. Currently, if the buffered mode
* is enabled, the LRADC takes LRADC_DELAY_TIMER_LOOP samples of data before
* triggering IRQ. The sampling happens every (LRADC_DELAY_TIMER_PER / 2000)
* seconds. The result is that the samples arrive every 500mS.
*/
#define LRADC_DELAY_TIMER_PER 200
#define LRADC_DELAY_TIMER_LOOP 5
/*
* Once the pen touches the touchscreen, the touchscreen switches from
* IRQ-driven mode to polling mode to prevent interrupt storm. The polling
* is realized by worker thread, which is called every 20 or so milliseconds.
* This gives the touchscreen enough fluence and does not strain the system
* too much.
*/
#define LRADC_TS_SAMPLE_DELAY_MS 5
/*
* The LRADC reads the following amount of samples from each touchscreen
* channel and the driver then computes avarage of these.
*/
#define LRADC_TS_SAMPLE_AMOUNT 4
enum mxs_lradc_id {
IMX23_LRADC,
IMX28_LRADC,
};
static const char * const mx23_lradc_irq_names[] = {
"mxs-lradc-touchscreen",
"mxs-lradc-channel0",
"mxs-lradc-channel1",
"mxs-lradc-channel2",
"mxs-lradc-channel3",
"mxs-lradc-channel4",
"mxs-lradc-channel5",
"mxs-lradc-channel6",
"mxs-lradc-channel7",
};
static const char * const mx28_lradc_irq_names[] = {
"mxs-lradc-touchscreen",
"mxs-lradc-thresh0",
"mxs-lradc-thresh1",
"mxs-lradc-channel0",
"mxs-lradc-channel1",
"mxs-lradc-channel2",
"mxs-lradc-channel3",
"mxs-lradc-channel4",
"mxs-lradc-channel5",
"mxs-lradc-channel6",
"mxs-lradc-channel7",
"mxs-lradc-button0",
"mxs-lradc-button1",
};
struct mxs_lradc_of_config {
const int irq_count;
const char * const *irq_name;
};
static const struct mxs_lradc_of_config mxs_lradc_of_config[] = {
[IMX23_LRADC] = {
.irq_count = ARRAY_SIZE(mx23_lradc_irq_names),
.irq_name = mx23_lradc_irq_names,
},
[IMX28_LRADC] = {
.irq_count = ARRAY_SIZE(mx28_lradc_irq_names),
.irq_name = mx28_lradc_irq_names,
},
};
enum mxs_lradc_ts {
MXS_LRADC_TOUCHSCREEN_NONE = 0,
MXS_LRADC_TOUCHSCREEN_4WIRE,
MXS_LRADC_TOUCHSCREEN_5WIRE,
};
struct mxs_lradc {
struct device *dev;
void __iomem *base;
int irq[13];
uint32_t *buffer;
struct iio_trigger *trig;
struct mutex lock;
struct completion completion;
/*
* Touchscreen LRADC channels receives a private slot in the CTRL4
* register, the slot #7. Therefore only 7 slots instead of 8 in the
* CTRL4 register can be mapped to LRADC channels when using the
* touchscreen.
*
* Furthermore, certain LRADC channels are shared between touchscreen
* and/or touch-buttons and generic LRADC block. Therefore when using
* either of these, these channels are not available for the regular
* sampling. The shared channels are as follows:
*
* CH0 -- Touch button #0
* CH1 -- Touch button #1
* CH2 -- Touch screen XPUL
* CH3 -- Touch screen YPLL
* CH4 -- Touch screen XNUL
* CH5 -- Touch screen YNLR
* CH6 -- Touch screen WIPER (5-wire only)
*
* The bitfields below represents which parts of the LRADC block are
* switched into special mode of operation. These channels can not
* be sampled as regular LRADC channels. The driver will refuse any
* attempt to sample these channels.
*/
#define CHAN_MASK_TOUCHBUTTON (0x3 << 0)
#define CHAN_MASK_TOUCHSCREEN_4WIRE (0xf << 2)
#define CHAN_MASK_TOUCHSCREEN_5WIRE (0x1f << 2)
enum mxs_lradc_ts use_touchscreen;
bool stop_touchscreen;
bool use_touchbutton;
struct input_dev *ts_input;
struct work_struct ts_work;
};
#define LRADC_CTRL0 0x00
#define LRADC_CTRL0_TOUCH_DETECT_ENABLE (1 << 23)
#define LRADC_CTRL0_TOUCH_SCREEN_TYPE (1 << 22)
#define LRADC_CTRL0_YNNSW /* YM */ (1 << 21)
#define LRADC_CTRL0_YPNSW /* YP */ (1 << 20)
#define LRADC_CTRL0_YPPSW /* YP */ (1 << 19)
#define LRADC_CTRL0_XNNSW /* XM */ (1 << 18)
#define LRADC_CTRL0_XNPSW /* XM */ (1 << 17)
#define LRADC_CTRL0_XPPSW /* XP */ (1 << 16)
#define LRADC_CTRL0_PLATE_MASK (0x3f << 16)
#define LRADC_CTRL1 0x10
#define LRADC_CTRL1_TOUCH_DETECT_IRQ_EN (1 << 24)
#define LRADC_CTRL1_LRADC_IRQ_EN(n) (1 << ((n) + 16))
#define LRADC_CTRL1_LRADC_IRQ_EN_MASK (0x1fff << 16)
#define LRADC_CTRL1_LRADC_IRQ_EN_OFFSET 16
#define LRADC_CTRL1_TOUCH_DETECT_IRQ (1 << 8)
#define LRADC_CTRL1_LRADC_IRQ(n) (1 << (n))
#define LRADC_CTRL1_LRADC_IRQ_MASK 0x1fff
#define LRADC_CTRL1_LRADC_IRQ_OFFSET 0
#define LRADC_CTRL2 0x20
#define LRADC_CTRL2_TEMPSENSE_PWD (1 << 15)
#define LRADC_STATUS 0x40
#define LRADC_STATUS_TOUCH_DETECT_RAW (1 << 0)
#define LRADC_CH(n) (0x50 + (0x10 * (n)))
#define LRADC_CH_ACCUMULATE (1 << 29)
#define LRADC_CH_NUM_SAMPLES_MASK (0x1f << 24)
#define LRADC_CH_NUM_SAMPLES_OFFSET 24
#define LRADC_CH_VALUE_MASK 0x3ffff
#define LRADC_CH_VALUE_OFFSET 0
#define LRADC_DELAY(n) (0xd0 + (0x10 * (n)))
#define LRADC_DELAY_TRIGGER_LRADCS_MASK (0xff << 24)
#define LRADC_DELAY_TRIGGER_LRADCS_OFFSET 24
#define LRADC_DELAY_KICK (1 << 20)
#define LRADC_DELAY_TRIGGER_DELAYS_MASK (0xf << 16)
#define LRADC_DELAY_TRIGGER_DELAYS_OFFSET 16
#define LRADC_DELAY_LOOP_COUNT_MASK (0x1f << 11)
#define LRADC_DELAY_LOOP_COUNT_OFFSET 11
#define LRADC_DELAY_DELAY_MASK 0x7ff
#define LRADC_DELAY_DELAY_OFFSET 0
#define LRADC_CTRL4 0x140
#define LRADC_CTRL4_LRADCSELECT_MASK(n) (0xf << ((n) * 4))
#define LRADC_CTRL4_LRADCSELECT_OFFSET(n) ((n) * 4)
/*
* Raw I/O operations
*/
static int mxs_lradc_read_raw(struct iio_dev *iio_dev,
const struct iio_chan_spec *chan,
int *val, int *val2, long m)
{
struct mxs_lradc *lradc = iio_priv(iio_dev);
int ret;
if (m != IIO_CHAN_INFO_RAW)
return -EINVAL;
/* Check for invalid channel */
if (chan->channel > LRADC_MAX_TOTAL_CHANS)
return -EINVAL;
/*
* See if there is no buffered operation in progess. If there is, simply
* bail out. This can be improved to support both buffered and raw IO at
* the same time, yet the code becomes horribly complicated. Therefore I
* applied KISS principle here.
*/
ret = mutex_trylock(&lradc->lock);
if (!ret)
return -EBUSY;
INIT_COMPLETION(lradc->completion);
/*
* No buffered operation in progress, map the channel and trigger it.
* Virtual channel 0 is always used here as the others are always not
* used if doing raw sampling.
*/
writel(LRADC_CTRL1_LRADC_IRQ_EN_MASK,
lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
writel(0xff, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
/* Clean the slot's previous content, then set new one. */
writel(LRADC_CTRL4_LRADCSELECT_MASK(0),
lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_CLR);
writel(chan->channel, lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_SET);
writel(0, lradc->base + LRADC_CH(0));
/* Enable the IRQ and start sampling the channel. */
writel(LRADC_CTRL1_LRADC_IRQ_EN(0),
lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_SET);
writel(1 << 0, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
/* Wait for completion on the channel, 1 second max. */
ret = wait_for_completion_killable_timeout(&lradc->completion, HZ);
if (!ret)
ret = -ETIMEDOUT;
if (ret < 0)
goto err;
/* Read the data. */
*val = readl(lradc->base + LRADC_CH(0)) & LRADC_CH_VALUE_MASK;
ret = IIO_VAL_INT;
err:
writel(LRADC_CTRL1_LRADC_IRQ_EN(0),
lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
mutex_unlock(&lradc->lock);
return ret;
}
static const struct iio_info mxs_lradc_iio_info = {
.driver_module = THIS_MODULE,
.read_raw = mxs_lradc_read_raw,
};
/*
* Touchscreen handling
*/
enum lradc_ts_plate {
LRADC_SAMPLE_X,
LRADC_SAMPLE_Y,
LRADC_SAMPLE_PRESSURE,
};
static int mxs_lradc_ts_touched(struct mxs_lradc *lradc)
{
uint32_t reg;
/* Enable touch detection. */
writel(LRADC_CTRL0_PLATE_MASK,
lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
writel(LRADC_CTRL0_TOUCH_DETECT_ENABLE,
lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
msleep(LRADC_TS_SAMPLE_DELAY_MS);
reg = readl(lradc->base + LRADC_STATUS);
return reg & LRADC_STATUS_TOUCH_DETECT_RAW;
}
static int32_t mxs_lradc_ts_sample(struct mxs_lradc *lradc,
enum lradc_ts_plate plate, int change)
{
unsigned long delay, jiff;
uint32_t reg, ctrl0 = 0, chan = 0;
/* The touchscreen always uses CTRL4 slot #7. */
const uint8_t slot = 7;
uint32_t val;
/*
* There are three correct configurations of the controller sampling
* the touchscreen, each of these configuration provides different
* information from the touchscreen.
*
* The following table describes the sampling configurations:
* +-------------+-------+-------+-------+
* | Wire \ Axis | X | Y | Z |
* +---------------------+-------+-------+
* | X+ (CH2) | HI | TS | TS |
* +-------------+-------+-------+-------+
* | X- (CH4) | LO | SH | HI |
* +-------------+-------+-------+-------+
* | Y+ (CH3) | SH | HI | HI |
* +-------------+-------+-------+-------+
* | Y- (CH5) | TS | LO | SH |
* +-------------+-------+-------+-------+
*
* HI ... strong '1' ; LO ... strong '0'
* SH ... sample here ; TS ... tri-state
*
* There are a few other ways of obtaining the Z coordinate
* (aka. pressure), but the one in the table seems to be the
* most reliable one.
*/
switch (plate) {
case LRADC_SAMPLE_X:
ctrl0 = LRADC_CTRL0_XPPSW | LRADC_CTRL0_XNNSW;
chan = 3;
break;
case LRADC_SAMPLE_Y:
ctrl0 = LRADC_CTRL0_YPPSW | LRADC_CTRL0_YNNSW;
chan = 4;
break;
case LRADC_SAMPLE_PRESSURE:
ctrl0 = LRADC_CTRL0_YPPSW | LRADC_CTRL0_XNNSW;
chan = 5;
break;
}
if (change) {
writel(LRADC_CTRL0_PLATE_MASK,
lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
writel(ctrl0, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
writel(LRADC_CTRL4_LRADCSELECT_MASK(slot),
lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_CLR);
writel(chan << LRADC_CTRL4_LRADCSELECT_OFFSET(slot),
lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_SET);
}
writel(0xffffffff, lradc->base + LRADC_CH(slot) + STMP_OFFSET_REG_CLR);
writel(1 << slot, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
delay = jiffies + msecs_to_jiffies(LRADC_TS_SAMPLE_DELAY_MS);
do {
jiff = jiffies;
reg = readl_relaxed(lradc->base + LRADC_CTRL1);
if (reg & LRADC_CTRL1_LRADC_IRQ(slot))
break;
} while (time_before(jiff, delay));
writel(LRADC_CTRL1_LRADC_IRQ(slot),
lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
if (time_after_eq(jiff, delay))
return -ETIMEDOUT;
val = readl(lradc->base + LRADC_CH(slot));
val &= LRADC_CH_VALUE_MASK;
return val;
}
static int32_t mxs_lradc_ts_sample_filter(struct mxs_lradc *lradc,
enum lradc_ts_plate plate)
{
int32_t val, tot = 0;
int i;
val = mxs_lradc_ts_sample(lradc, plate, 1);
/* Delay a bit so the touchscreen is stable. */
mdelay(2);
for (i = 0; i < LRADC_TS_SAMPLE_AMOUNT; i++) {
val = mxs_lradc_ts_sample(lradc, plate, 0);
tot += val;
}
return tot / LRADC_TS_SAMPLE_AMOUNT;
}
static void mxs_lradc_ts_work(struct work_struct *ts_work)
{
struct mxs_lradc *lradc = container_of(ts_work,
struct mxs_lradc, ts_work);
int val_x, val_y, val_p;
bool valid = false;
while (mxs_lradc_ts_touched(lradc)) {
/* Disable touch detector so we can sample the touchscreen. */
writel(LRADC_CTRL0_TOUCH_DETECT_ENABLE,
lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
if (likely(valid)) {
input_report_abs(lradc->ts_input, ABS_X, val_x);
input_report_abs(lradc->ts_input, ABS_Y, val_y);
input_report_abs(lradc->ts_input, ABS_PRESSURE, val_p);
input_report_key(lradc->ts_input, BTN_TOUCH, 1);
input_sync(lradc->ts_input);
}
valid = false;
val_x = mxs_lradc_ts_sample_filter(lradc, LRADC_SAMPLE_X);
if (val_x < 0)
continue;
val_y = mxs_lradc_ts_sample_filter(lradc, LRADC_SAMPLE_Y);
if (val_y < 0)
continue;
val_p = mxs_lradc_ts_sample_filter(lradc, LRADC_SAMPLE_PRESSURE);
if (val_p < 0)
continue;
valid = true;
}
input_report_abs(lradc->ts_input, ABS_PRESSURE, 0);
input_report_key(lradc->ts_input, BTN_TOUCH, 0);
input_sync(lradc->ts_input);
/* Do not restart the TS IRQ if the driver is shutting down. */
if (lradc->stop_touchscreen)
return;
/* Restart the touchscreen interrupts. */
writel(LRADC_CTRL1_TOUCH_DETECT_IRQ,
lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
writel(LRADC_CTRL1_TOUCH_DETECT_IRQ_EN,
lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_SET);
}
static int mxs_lradc_ts_open(struct input_dev *dev)
{
struct mxs_lradc *lradc = input_get_drvdata(dev);
/* The touchscreen is starting. */
lradc->stop_touchscreen = false;
/* Enable the touch-detect circuitry. */
writel(LRADC_CTRL0_TOUCH_DETECT_ENABLE,
lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
/* Enable the touch-detect IRQ. */
writel(LRADC_CTRL1_TOUCH_DETECT_IRQ_EN,
lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_SET);
return 0;
}
static void mxs_lradc_ts_close(struct input_dev *dev)
{
struct mxs_lradc *lradc = input_get_drvdata(dev);
/* Indicate the touchscreen is stopping. */
lradc->stop_touchscreen = true;
mb();
/* Wait until touchscreen thread finishes any possible remnants. */
cancel_work_sync(&lradc->ts_work);
/* Disable touchscreen touch-detect IRQ. */
writel(LRADC_CTRL1_TOUCH_DETECT_IRQ_EN,
lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
/* Power-down touchscreen touch-detect circuitry. */
writel(LRADC_CTRL0_TOUCH_DETECT_ENABLE,
lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
}
static int mxs_lradc_ts_register(struct mxs_lradc *lradc)
{
struct input_dev *input;
struct device *dev = lradc->dev;
int ret;
if (!lradc->use_touchscreen)
return 0;
input = input_allocate_device();
if (!input) {
dev_err(dev, "Failed to allocate TS device!\n");
return -ENOMEM;
}
input->name = DRIVER_NAME;
input->id.bustype = BUS_HOST;
input->dev.parent = dev;
input->open = mxs_lradc_ts_open;
input->close = mxs_lradc_ts_close;
__set_bit(EV_ABS, input->evbit);
__set_bit(EV_KEY, input->evbit);
__set_bit(BTN_TOUCH, input->keybit);
input_set_abs_params(input, ABS_X, 0, LRADC_CH_VALUE_MASK, 0, 0);
input_set_abs_params(input, ABS_Y, 0, LRADC_CH_VALUE_MASK, 0, 0);
input_set_abs_params(input, ABS_PRESSURE, 0, LRADC_CH_VALUE_MASK, 0, 0);
lradc->ts_input = input;
input_set_drvdata(input, lradc);
ret = input_register_device(input);
if (ret)
input_free_device(lradc->ts_input);
return ret;
}
static void mxs_lradc_ts_unregister(struct mxs_lradc *lradc)
{
if (!lradc->use_touchscreen)
return;
cancel_work_sync(&lradc->ts_work);
input_unregister_device(lradc->ts_input);
}
/*
* IRQ Handling
*/
static irqreturn_t mxs_lradc_handle_irq(int irq, void *data)
{
struct iio_dev *iio = data;
struct mxs_lradc *lradc = iio_priv(iio);
unsigned long reg = readl(lradc->base + LRADC_CTRL1);
const uint32_t ts_irq_mask =
LRADC_CTRL1_TOUCH_DETECT_IRQ_EN |
LRADC_CTRL1_TOUCH_DETECT_IRQ;
if (!(reg & LRADC_CTRL1_LRADC_IRQ_MASK))
return IRQ_NONE;
/*
* Touchscreen IRQ handling code has priority and therefore
* is placed here. In case touchscreen IRQ arrives, disable
* it ASAP
*/
if (reg & LRADC_CTRL1_TOUCH_DETECT_IRQ) {
writel(ts_irq_mask,
lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
if (!lradc->stop_touchscreen)
schedule_work(&lradc->ts_work);
}
if (iio_buffer_enabled(iio))
iio_trigger_poll(iio->trig, iio_get_time_ns());
else if (reg & LRADC_CTRL1_LRADC_IRQ(0))
complete(&lradc->completion);
writel(reg & LRADC_CTRL1_LRADC_IRQ_MASK,
lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
return IRQ_HANDLED;
}
/*
* Trigger handling
*/
static irqreturn_t mxs_lradc_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *iio = pf->indio_dev;
struct mxs_lradc *lradc = iio_priv(iio);
const uint32_t chan_value = LRADC_CH_ACCUMULATE |
((LRADC_DELAY_TIMER_LOOP - 1) << LRADC_CH_NUM_SAMPLES_OFFSET);
unsigned int i, j = 0;
for_each_set_bit(i, iio->active_scan_mask, iio->masklength) {
lradc->buffer[j] = readl(lradc->base + LRADC_CH(j));
writel(chan_value, lradc->base + LRADC_CH(j));
lradc->buffer[j] &= LRADC_CH_VALUE_MASK;
lradc->buffer[j] /= LRADC_DELAY_TIMER_LOOP;
j++;
}
if (iio->scan_timestamp) {
s64 *timestamp = (s64 *)((u8 *)lradc->buffer +
ALIGN(j, sizeof(s64)));
*timestamp = pf->timestamp;
}
iio_push_to_buffers(iio, (u8 *)lradc->buffer);
iio_trigger_notify_done(iio->trig);
return IRQ_HANDLED;
}
static int mxs_lradc_configure_trigger(struct iio_trigger *trig, bool state)
{
struct iio_dev *iio = iio_trigger_get_drvdata(trig);
struct mxs_lradc *lradc = iio_priv(iio);
const uint32_t st = state ? STMP_OFFSET_REG_SET : STMP_OFFSET_REG_CLR;
writel(LRADC_DELAY_KICK, lradc->base + LRADC_DELAY(0) + st);
return 0;
}
static const struct iio_trigger_ops mxs_lradc_trigger_ops = {
.owner = THIS_MODULE,
.set_trigger_state = &mxs_lradc_configure_trigger,
};
static int mxs_lradc_trigger_init(struct iio_dev *iio)
{
int ret;
struct iio_trigger *trig;
struct mxs_lradc *lradc = iio_priv(iio);
trig = iio_trigger_alloc("%s-dev%i", iio->name, iio->id);
if (trig == NULL)
return -ENOMEM;
trig->dev.parent = lradc->dev;
iio_trigger_set_drvdata(trig, iio);
trig->ops = &mxs_lradc_trigger_ops;
ret = iio_trigger_register(trig);
if (ret) {
iio_trigger_free(trig);
return ret;
}
lradc->trig = trig;
return 0;
}
static void mxs_lradc_trigger_remove(struct iio_dev *iio)
{
struct mxs_lradc *lradc = iio_priv(iio);
iio_trigger_unregister(lradc->trig);
iio_trigger_free(lradc->trig);
}
static int mxs_lradc_buffer_preenable(struct iio_dev *iio)
{
struct mxs_lradc *lradc = iio_priv(iio);
int ret = 0, chan, ofs = 0;
unsigned long enable = 0;
uint32_t ctrl4_set = 0;
uint32_t ctrl4_clr = 0;
uint32_t ctrl1_irq = 0;
const uint32_t chan_value = LRADC_CH_ACCUMULATE |
((LRADC_DELAY_TIMER_LOOP - 1) << LRADC_CH_NUM_SAMPLES_OFFSET);
const int len = bitmap_weight(iio->active_scan_mask, LRADC_MAX_TOTAL_CHANS);
if (!len)
return -EINVAL;
/*
* Lock the driver so raw access can not be done during buffered
* operation. This simplifies the code a lot.
*/
ret = mutex_trylock(&lradc->lock);
if (!ret)
return -EBUSY;
lradc->buffer = kmalloc(len * sizeof(*lradc->buffer), GFP_KERNEL);
if (!lradc->buffer) {
ret = -ENOMEM;
goto err_mem;
}
ret = iio_sw_buffer_preenable(iio);
if (ret < 0)
goto err_buf;
writel(LRADC_CTRL1_LRADC_IRQ_EN_MASK,
lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
writel(0xff, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
for_each_set_bit(chan, iio->active_scan_mask, LRADC_MAX_TOTAL_CHANS) {
ctrl4_set |= chan << LRADC_CTRL4_LRADCSELECT_OFFSET(ofs);
ctrl4_clr |= LRADC_CTRL4_LRADCSELECT_MASK(ofs);
ctrl1_irq |= LRADC_CTRL1_LRADC_IRQ_EN(ofs);
writel(chan_value, lradc->base + LRADC_CH(ofs));
bitmap_set(&enable, ofs, 1);
ofs++;
}
writel(LRADC_DELAY_TRIGGER_LRADCS_MASK | LRADC_DELAY_KICK,
lradc->base + LRADC_DELAY(0) + STMP_OFFSET_REG_CLR);
writel(ctrl4_clr, lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_CLR);
writel(ctrl4_set, lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_SET);
writel(ctrl1_irq, lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_SET);
writel(enable << LRADC_DELAY_TRIGGER_LRADCS_OFFSET,
lradc->base + LRADC_DELAY(0) + STMP_OFFSET_REG_SET);
return 0;
err_buf:
kfree(lradc->buffer);
err_mem:
mutex_unlock(&lradc->lock);
return ret;
}
static int mxs_lradc_buffer_postdisable(struct iio_dev *iio)
{
struct mxs_lradc *lradc = iio_priv(iio);
writel(LRADC_DELAY_TRIGGER_LRADCS_MASK | LRADC_DELAY_KICK,
lradc->base + LRADC_DELAY(0) + STMP_OFFSET_REG_CLR);
writel(0xff, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
writel(LRADC_CTRL1_LRADC_IRQ_EN_MASK,
lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
kfree(lradc->buffer);
mutex_unlock(&lradc->lock);
return 0;
}
static bool mxs_lradc_validate_scan_mask(struct iio_dev *iio,
const unsigned long *mask)
{
struct mxs_lradc *lradc = iio_priv(iio);
const int len = iio->masklength;
const int map_chans = bitmap_weight(mask, len);
int rsvd_chans = 0;
unsigned long rsvd_mask = 0;
if (lradc->use_touchbutton)
rsvd_mask |= CHAN_MASK_TOUCHBUTTON;
if (lradc->use_touchscreen == MXS_LRADC_TOUCHSCREEN_4WIRE)
rsvd_mask |= CHAN_MASK_TOUCHSCREEN_4WIRE;
if (lradc->use_touchscreen == MXS_LRADC_TOUCHSCREEN_5WIRE)
rsvd_mask |= CHAN_MASK_TOUCHSCREEN_5WIRE;
if (lradc->use_touchbutton)
rsvd_chans++;
if (lradc->use_touchscreen)
rsvd_chans++;
/* Test for attempts to map channels with special mode of operation. */
if (bitmap_intersects(mask, &rsvd_mask, len))
return false;
/* Test for attempts to map more channels then available slots. */
if (map_chans + rsvd_chans > LRADC_MAX_MAPPED_CHANS)
return false;
return true;
}
static const struct iio_buffer_setup_ops mxs_lradc_buffer_ops = {
.preenable = &mxs_lradc_buffer_preenable,
.postenable = &iio_triggered_buffer_postenable,
.predisable = &iio_triggered_buffer_predisable,
.postdisable = &mxs_lradc_buffer_postdisable,
.validate_scan_mask = &mxs_lradc_validate_scan_mask,
};
/*
* Driver initialization
*/
#define MXS_ADC_CHAN(idx, chan_type) { \
.type = (chan_type), \
.indexed = 1, \
.scan_index = (idx), \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.channel = (idx), \
.scan_type = { \
.sign = 'u', \
.realbits = 18, \
.storagebits = 32, \
}, \
}
static const struct iio_chan_spec mxs_lradc_chan_spec[] = {
MXS_ADC_CHAN(0, IIO_VOLTAGE),
MXS_ADC_CHAN(1, IIO_VOLTAGE),
MXS_ADC_CHAN(2, IIO_VOLTAGE),
MXS_ADC_CHAN(3, IIO_VOLTAGE),
MXS_ADC_CHAN(4, IIO_VOLTAGE),
MXS_ADC_CHAN(5, IIO_VOLTAGE),
MXS_ADC_CHAN(6, IIO_VOLTAGE),
MXS_ADC_CHAN(7, IIO_VOLTAGE), /* VBATT */
MXS_ADC_CHAN(8, IIO_TEMP), /* Temp sense 0 */
MXS_ADC_CHAN(9, IIO_TEMP), /* Temp sense 1 */
MXS_ADC_CHAN(10, IIO_VOLTAGE), /* VDDIO */
MXS_ADC_CHAN(11, IIO_VOLTAGE), /* VTH */
MXS_ADC_CHAN(12, IIO_VOLTAGE), /* VDDA */
MXS_ADC_CHAN(13, IIO_VOLTAGE), /* VDDD */
MXS_ADC_CHAN(14, IIO_VOLTAGE), /* VBG */
MXS_ADC_CHAN(15, IIO_VOLTAGE), /* VDD5V */
};
static void mxs_lradc_hw_init(struct mxs_lradc *lradc)
{
/* The ADC always uses DELAY CHANNEL 0. */
const uint32_t adc_cfg =
(1 << (LRADC_DELAY_TRIGGER_DELAYS_OFFSET + 0)) |
(LRADC_DELAY_TIMER_PER << LRADC_DELAY_DELAY_OFFSET);
stmp_reset_block(lradc->base);
/* Configure DELAY CHANNEL 0 for generic ADC sampling. */
writel(adc_cfg, lradc->base + LRADC_DELAY(0));
/* Disable remaining DELAY CHANNELs */
writel(0, lradc->base + LRADC_DELAY(1));
writel(0, lradc->base + LRADC_DELAY(2));
writel(0, lradc->base + LRADC_DELAY(3));
/* Configure the touchscreen type */
writel(LRADC_CTRL0_TOUCH_SCREEN_TYPE,
lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
if (lradc->use_touchscreen == MXS_LRADC_TOUCHSCREEN_5WIRE) {
writel(LRADC_CTRL0_TOUCH_SCREEN_TYPE,
lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
}
/* Start internal temperature sensing. */
writel(0, lradc->base + LRADC_CTRL2);
}
static void mxs_lradc_hw_stop(struct mxs_lradc *lradc)
{
int i;
writel(LRADC_CTRL1_LRADC_IRQ_EN_MASK,
lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
for (i = 0; i < LRADC_MAX_DELAY_CHANS; i++)
writel(0, lradc->base + LRADC_DELAY(i));
}
static const struct of_device_id mxs_lradc_dt_ids[] = {
{ .compatible = "fsl,imx23-lradc", .data = (void *)IMX23_LRADC, },
{ .compatible = "fsl,imx28-lradc", .data = (void *)IMX28_LRADC, },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, mxs_lradc_dt_ids);
static int mxs_lradc_probe(struct platform_device *pdev)
{
const struct of_device_id *of_id =
of_match_device(mxs_lradc_dt_ids, &pdev->dev);
const struct mxs_lradc_of_config *of_cfg =
&mxs_lradc_of_config[(enum mxs_lradc_id)of_id->data];
struct device *dev = &pdev->dev;
struct device_node *node = dev->of_node;
struct mxs_lradc *lradc;
struct iio_dev *iio;
struct resource *iores;
uint32_t ts_wires = 0;
int ret = 0;
int i;
/* Allocate the IIO device. */
iio = iio_device_alloc(sizeof(*lradc));
if (!iio) {
dev_err(dev, "Failed to allocate IIO device\n");
return -ENOMEM;
}
lradc = iio_priv(iio);
/* Grab the memory area */
iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
lradc->dev = &pdev->dev;
lradc->base = devm_ioremap_resource(dev, iores);
if (IS_ERR(lradc->base)) {
ret = PTR_ERR(lradc->base);
goto err_addr;
}
INIT_WORK(&lradc->ts_work, mxs_lradc_ts_work);
/* Check if touchscreen is enabled in DT. */
ret = of_property_read_u32(node, "fsl,lradc-touchscreen-wires",
&ts_wires);
if (ret)
dev_info(dev, "Touchscreen not enabled.\n");
else if (ts_wires == 4)
lradc->use_touchscreen = MXS_LRADC_TOUCHSCREEN_4WIRE;
else if (ts_wires == 5)
lradc->use_touchscreen = MXS_LRADC_TOUCHSCREEN_5WIRE;
else
dev_warn(dev, "Unsupported number of touchscreen wires (%d)\n",
ts_wires);
/* Grab all IRQ sources */
for (i = 0; i < of_cfg->irq_count; i++) {
lradc->irq[i] = platform_get_irq(pdev, i);
if (lradc->irq[i] < 0) {
ret = -EINVAL;
goto err_addr;
}
ret = devm_request_irq(dev, lradc->irq[i],
mxs_lradc_handle_irq, 0,
of_cfg->irq_name[i], iio);
if (ret)
goto err_addr;
}
platform_set_drvdata(pdev, iio);
init_completion(&lradc->completion);
mutex_init(&lradc->lock);
iio->name = pdev->name;
iio->dev.parent = &pdev->dev;
iio->info = &mxs_lradc_iio_info;
iio->modes = INDIO_DIRECT_MODE;
iio->channels = mxs_lradc_chan_spec;
iio->num_channels = ARRAY_SIZE(mxs_lradc_chan_spec);
ret = iio_triggered_buffer_setup(iio, &iio_pollfunc_store_time,
&mxs_lradc_trigger_handler,
&mxs_lradc_buffer_ops);
if (ret)
goto err_addr;
ret = mxs_lradc_trigger_init(iio);
if (ret)
goto err_trig;
/* Configure the hardware. */
mxs_lradc_hw_init(lradc);
/* Register the touchscreen input device. */
ret = mxs_lradc_ts_register(lradc);
if (ret)
goto err_dev;
/* Register IIO device. */
ret = iio_device_register(iio);
if (ret) {
dev_err(dev, "Failed to register IIO device\n");
goto err_ts;
}
return 0;
err_ts:
mxs_lradc_ts_unregister(lradc);
err_dev:
mxs_lradc_trigger_remove(iio);
err_trig:
iio_triggered_buffer_cleanup(iio);
err_addr:
iio_device_free(iio);
return ret;
}
static int mxs_lradc_remove(struct platform_device *pdev)
{
struct iio_dev *iio = platform_get_drvdata(pdev);
struct mxs_lradc *lradc = iio_priv(iio);
mxs_lradc_ts_unregister(lradc);
mxs_lradc_hw_stop(lradc);
iio_device_unregister(iio);
iio_triggered_buffer_cleanup(iio);
mxs_lradc_trigger_remove(iio);
iio_device_free(iio);
return 0;
}
static struct platform_driver mxs_lradc_driver = {
.driver = {
.name = DRIVER_NAME,
.owner = THIS_MODULE,
.of_match_table = mxs_lradc_dt_ids,
},
.probe = mxs_lradc_probe,
.remove = mxs_lradc_remove,
};
module_platform_driver(mxs_lradc_driver);
MODULE_AUTHOR("Marek Vasut <marex@denx.de>");
MODULE_DESCRIPTION("Freescale i.MX28 LRADC driver");
MODULE_LICENSE("GPL v2");