[PATCH 2/3 V2] iio: mxs: Implement support for touchscreen
Dmitry Torokhov
dmitry.torokhov at gmail.com
Wed Jan 9 19:57:50 EST 2013
Hi Marek,
On Wed, Dec 19, 2012 at 06:01:31PM +0100, Marek Vasut wrote:
> Ccing Dmitry.
>
> Also, Jonathan, can I get your review please?
>
> > This patch implements support for sampling of a touchscreen into
> > the MXS LRADC driver. The LRADC block allows configuring some of
> > it's channels into special mode where they either output the drive
> > voltage or sample it, allowing it to operate a 4-wire or 5-wire
> > resistive touchscreen.
> >
> > In case the touchscreen mode is enabled, the LRADC slot #7 is
> > reserved for touchscreen only, therefore it is not possible to
> > sample 8 LRADC channels at time, but only 7 channels.
> >
> > The touchscreen controller is configured such that the PENDOWN event
> > disables touchscreen interrupts and triggers execution of worker
> > thread, which then polls the touchscreen controller for X, Y and
> > Pressure values. This reduces the overhead of interrupt-driven
> > operation. Upon the PENUP event, the worker thread re-enables the
> > PENDOWN detection interrupt and exits.
> >
> > Signed-off-by: Marek Vasut <marex at denx.de>
> > Cc: Fabio Estevam <fabio.estevam at freescale.com>
> > Cc: Jonathan Cameron <jic23 at kernel.org>
> > Cc: Shawn Guo <shawn.guo at linaro.org>
> > ---
> > .../bindings/staging/iio/adc/mxs-lradc.txt | 6 +
> > drivers/staging/iio/adc/mxs-lradc.c | 469
> > +++++++++++++++++++- 2 files changed, 454 insertions(+), 21 deletions(-)
> >
> > V2: - Replace the use_touchscreen* with enum mxs_lradc_ts, which now tracks
> > touchscreen state (OFF, 4-wire, 5-wire)
> > - Add "stop_touchscreen" bit, which indicates the touchscreen is going
> > down and makes the driver not re-enable touchscreen interrupts and start
> > any new touchscreen works.
> > - Make all bitfields "unsigned int" instead of plain "int"
> > - Use switch(plate) in mxs_lradc_ts_sample()
> > - Cancel touchscreen thread in mxs_lradc_ts_close(), do this only after
> > we are sure touchscreen interrupt is off and will never be
> > re-enabled. This avoids serious race condition.
> > - Call input_free_device() if input_register_device() fails to avoid
> > memory leak.
> > - Do not call input_free_device() after input_unregister_device() in
> > mxs_lradc_ts_unregister() to avoid double-free
> >
> > diff --git
> > a/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt
> > b/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt index
> > 801d58c..4688205 100644
> > --- a/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt
> > +++ b/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt
> > @@ -5,6 +5,12 @@ Required properties:
> > - reg: Address and length of the register set for the device
> > - interrupts: Should contain the LRADC interrupts
> >
> > +Optional properties:
> > +- fsl,lradc-touchscreen-wires: Number of wires used to connect the
> > touchscreen + to LRADC. Valid value is
> > either 4 or 5. If this + property is not
> > present, then the touchscreen is + disabled.
> > +
> > Examples:
> >
> > lradc at 80050000 {
> > diff --git a/drivers/staging/iio/adc/mxs-lradc.c
> > b/drivers/staging/iio/adc/mxs-lradc.c index 6249957..52317ef 100644
> > --- a/drivers/staging/iio/adc/mxs-lradc.c
> > +++ b/drivers/staging/iio/adc/mxs-lradc.c
> > @@ -32,6 +32,8 @@
> > #include <linux/stmp_device.h>
> > #include <linux/bitops.h>
> > #include <linux/completion.h>
> > +#include <linux/delay.h>
> > +#include <linux/input.h>
> >
> > #include <mach/mxs.h>
> > #include <mach/common.h>
> > @@ -59,6 +61,21 @@
> > #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
> > +
> > static const char * const mxs_lradc_irq_name[] = {
> > "mxs-lradc-touchscreen",
> > "mxs-lradc-thresh0",
> > @@ -75,6 +92,12 @@ static const char * const mxs_lradc_irq_name[] = {
> > "mxs-lradc-button1",
> > };
> >
> > +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;
> > @@ -86,21 +109,69 @@ struct mxs_lradc {
> > 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;
> > + unsigned int stop_touchscreen:1;
> > + unsigned int use_touchbutton:1;
Can we make them bools instead of bit fields?
> > +
> > + 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_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_LRADC_IRQ(n) (1 << (n))
> > -#define LRADC_CTRL1_LRADC_IRQ_MASK 0x1fff
> > +#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)
> > @@ -132,6 +203,7 @@ static int mxs_lradc_read_raw(struct iio_dev *iio_dev,
> > {
> > struct mxs_lradc *lradc = iio_priv(iio_dev);
> > int ret;
> > + unsigned long mask;
> >
> > if (m != IIO_CHAN_INFO_RAW)
> > return -EINVAL;
> > @@ -140,6 +212,12 @@ static int mxs_lradc_read_raw(struct iio_dev *iio_dev,
> > if (chan->channel > LRADC_MAX_TOTAL_CHANS)
> > return -EINVAL;
> >
> > + /* Validate the channel if it doesn't intersect with reserved chans. */
> > + bitmap_set(&mask, chan->channel, 1);
> > + ret = iio_validate_scan_mask_onehot(iio_dev, &mask);
> > + if (ret)
> > + 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
> > @@ -161,7 +239,11 @@ static int mxs_lradc_read_raw(struct iio_dev *iio_dev,
> > lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
> > writel(0xff, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
> >
> > - writel(chan->channel, lradc->base + LRADC_CTRL4);
> > + /* 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. */
> > @@ -195,6 +277,272 @@ static const struct iio_info mxs_lradc_iio_info = {
> > };
> >
> > /*
> > + * 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 = 0;
> > +
> > + /* 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 = 1;
> > +
> > + /* 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);
These 2 writes are racing with writes in mxs_lradc_ts_work(). I think
you need to:
lradc->stop_touchscreen = true;
mb();
cancel_work_sync(&lradc->ts_work);
writel(LRADC_CTRL1_TOUCH_DETECT_IRQ_EN,
lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
...
> > +
> > + /* Wait until touchscreen thread finishes any possible remnants. */
> > + cancel_work_sync(&lradc->ts_work);
> > +}
> > +
> > +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_warn(dev, "Failed to allocate TS device, disabling.\n");
> > + lradc->use_touchscreen = MXS_LRADC_TOUCHSCREEN_NONE;
> > + return 0;
> > + }
> > +
> > + 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;
So why is allocation failure is not fatal bur registration is? I'd make
both fatal.
> > +}
> > +
> > +static void mxs_lradc_ts_unregister(struct mxs_lradc *lradc)
> > +{
> > + if (!lradc->use_touchscreen)
> > + return;
> > +
> > + if (!lradc->ts_input)
> > + return;
Do we really need to check both conditions?
> > +
> > + 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)
> > @@ -202,14 +550,24 @@ 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 shall probably have priority
> > - * and therefore shall be placed here.
> > + * 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());
> > @@ -306,8 +664,10 @@ static int mxs_lradc_buffer_preenable(struct iio_dev
> > *iio) {
> > struct mxs_lradc *lradc = iio_priv(iio);
> > struct iio_buffer *buffer = iio->buffer;
> > - int ret = 0, chan, ofs = 0, enable = 0;
> > - uint32_t ctrl4 = 0;
> > + 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);
> > @@ -339,17 +699,20 @@ static int mxs_lradc_buffer_preenable(struct iio_dev
> > *iio) writel(0xff, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
> >
> > for_each_set_bit(chan, buffer->scan_mask, LRADC_MAX_TOTAL_CHANS) {
> > - ctrl4 |= chan << LRADC_CTRL4_LRADCSELECT_OFFSET(ofs);
> > + 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));
> > - enable |= 1 << 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, lradc->base + LRADC_CTRL4);
> > + 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,
> > @@ -384,9 +747,33 @@ static int mxs_lradc_buffer_postdisable(struct iio_dev
> > *iio) static bool mxs_lradc_validate_scan_mask(struct iio_dev *iio,
> > const unsigned long *mask)
> > {
> > - const int mw = bitmap_weight(mask, iio->masklength);
> > -
> > - return mw <= LRADC_MAX_MAPPED_CHANS;
> > + 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 0;
> > +
> > + /* Test for attempts to map more channels then available slots. */
> > + if (map_chans + rsvd_chans > LRADC_MAX_MAPPED_CHANS)
> > + return 0;
> > +
> > + return 1;
> > }
> >
> > static const struct iio_buffer_setup_ops mxs_lradc_buffer_ops = {
> > @@ -435,15 +822,29 @@ static const struct iio_chan_spec
> > mxs_lradc_chan_spec[] = {
> >
> > static void mxs_lradc_hw_init(struct mxs_lradc *lradc)
> > {
> > - int i;
> > - const uint32_t cfg =
> > + /* 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);
> >
> > - for (i = 0; i < LRADC_MAX_DELAY_CHANS; i++)
> > - writel(cfg | (1 << (LRADC_DELAY_TRIGGER_DELAYS_OFFSET + i)),
> > - lradc->base + LRADC_DELAY(i));
> > + /* 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);
> > @@ -463,9 +864,11 @@ static void mxs_lradc_hw_stop(struct mxs_lradc *lradc)
> > static int __devinit mxs_lradc_probe(struct platform_device *pdev)
__devinits must go now.
> > {
> > 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;
> >
> > @@ -487,6 +890,21 @@ static int __devinit mxs_lradc_probe(struct
> > platform_device *pdev) 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 < 13; i++) {
> > lradc->irq[i] = platform_get_irq(pdev, i);
> > @@ -524,11 +942,16 @@ static int __devinit mxs_lradc_probe(struct
> > platform_device *pdev) if (ret)
> > goto err_trig;
> >
> > + /* 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_dev;
> > + goto err_ts;
> > }
> >
> > /* Configure the hardware. */
> > @@ -536,6 +959,8 @@ static int __devinit mxs_lradc_probe(struct
> > platform_device *pdev)
> >
> > return 0;
> >
> > +err_ts:
> > + mxs_lradc_ts_unregister(lradc);
> > err_dev:
> > mxs_lradc_trigger_remove(iio);
> > err_trig:
> > @@ -550,6 +975,8 @@ static int __devexit 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);
Thanks.
--
Dmitry
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