[PATCH 5/6] Staging/iio/adc/touchscreen/MXS: add interrupt driven touch detection
Jonathan Cameron
jic23 at kernel.org
Sun Sep 15 10:56:25 UTC 2013
On 09/11/13 09:18, Juergen Beisert wrote:
> For battery driven systems it is a very bad idea to collect the touchscreen
> data within a kernel busy loop.
>
> This change uses the features of the hardware to delay and accumulate samples in
> hardware to avoid a high interrupt and CPU load.
>
> Note: this is only tested on an i.MX23 SoC yet.
>
> Signed-off-by: Juergen Beisert <jbe at pengutronix.de>
> CC: linux-arm-kernel at lists.infradead.org
> CC: devel at driverdev.osuosl.org
> CC: Marek Vasut <marex at denx.de>
> CC: Fabio Estevam <fabio.estevam at freescale.com>
> CC: Jonathan Cameron <jic23 at cam.ac.uk>
While this driver is placed in IIO within staging at the moment, these changes are definitely
input related. Hence I have cc'd Dmitry and the input list.
I am personaly a little uncomfortable that we have such a complex bit of input code sat
within an IIO driver but such is life.
> ---
> drivers/staging/iio/adc/mxs-lradc.c | 530 ++++++++++++++++++++++++++++++++----
> 1 file changed, 476 insertions(+), 54 deletions(-)
>
> diff --git a/drivers/staging/iio/adc/mxs-lradc.c b/drivers/staging/iio/adc/mxs-lradc.c
> index c81b186..185f068 100644
> --- a/drivers/staging/iio/adc/mxs-lradc.c
> +++ b/drivers/staging/iio/adc/mxs-lradc.c
> @@ -129,6 +129,17 @@ enum mxs_lradc_ts {
> MXS_LRADC_TOUCHSCREEN_5WIRE,
> };
>
> +/*
> + * Touchscreen handling
> + */
> +enum lradc_ts_plate {
> + LRADC_TOUCH = 0,
> + LRADC_SAMPLE_X,
> + LRADC_SAMPLE_Y,
> + LRADC_SAMPLE_PRESSURE,
> + LRADC_SAMPLE_VALID,
> +};
> +
> struct mxs_lradc {
> struct device *dev;
> void __iomem *base;
> @@ -169,13 +180,25 @@ struct mxs_lradc {
> #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;
>
> enum mxs_lradc_id soc;
> + enum lradc_ts_plate cur_plate; /* statemachine */
> + bool ts_valid;
> + unsigned ts_x_pos;
> + unsigned ts_y_pos;
> + unsigned ts_pressure;
> +
> + /* handle touchscreen's physical behaviour */
> + /* samples per coordinate */
> + unsigned over_sample_cnt;
> + /* time clocks between samples */
> + unsigned over_sample_delay;
> + /* time in clocks to wait after the plates where switched */
> + unsigned settling_delay;
> };
>
> #define LRADC_CTRL0 0x00
> @@ -227,19 +250,33 @@ struct mxs_lradc {
> #define LRADC_CH_ACCUMULATE (1 << 29)
> #define LRADC_CH_NUM_SAMPLES_MASK (0x1f << 24)
> #define LRADC_CH_NUM_SAMPLES_OFFSET 24
> +#define LRADC_CH_NUM_SAMPLES(x) \
> + ((x) << LRADC_CH_NUM_SAMPLES_OFFSET)
> #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_TRIGGER(x) \
> + (((x) << LRADC_DELAY_TRIGGER_LRADCS_OFFSET) & \
> + LRADC_DELAY_TRIGGER_LRADCS_MASK)
> #define LRADC_DELAY_KICK (1 << 20)
> #define LRADC_DELAY_TRIGGER_DELAYS_MASK (0xf << 16)
> #define LRADC_DELAY_TRIGGER_DELAYS_OFFSET 16
> +#define LRADC_DELAY_TRIGGER_DELAYS(x) \
> + (((x) << LRADC_DELAY_TRIGGER_DELAYS_OFFSET) & \
> + LRADC_DELAY_TRIGGER_DELAYS_MASK)
> #define LRADC_DELAY_LOOP_COUNT_MASK (0x1f << 11)
> #define LRADC_DELAY_LOOP_COUNT_OFFSET 11
> +#define LRADC_DELAY_LOOP(x) \
> + (((x) << LRADC_DELAY_LOOP_COUNT_OFFSET) & \
> + LRADC_DELAY_LOOP_COUNT_MASK)
> #define LRADC_DELAY_DELAY_MASK 0x7ff
> #define LRADC_DELAY_DELAY_OFFSET 0
> +#define LRADC_DELAY_DELAY(x) \
> + (((x) << LRADC_DELAY_DELAY_OFFSET) & \
> + LRADC_DELAY_DELAY_MASK)
>
> #define LRADC_CTRL4 0x140
> #define LRADC_CTRL4_LRADCSELECT_MASK(n) (0xf << ((n) * 4))
> @@ -312,6 +349,404 @@ static u32 mxs_lradc_drive_pressure(struct mxs_lradc *lradc)
> return LRADC_CTRL0_MX28_YPPSW | LRADC_CTRL0_MX28_XNNSW;
> }
>
> +static bool mxs_lradc_check_touch_event(struct mxs_lradc *lradc)
> +{
> + return !!(readl(lradc->base + LRADC_STATUS) &
> + LRADC_STATUS_TOUCH_DETECT_RAW);
> +}
> +
> +static void mxs_lradc_setup_ts_channel(struct mxs_lradc *lradc, unsigned ch)
> +{
> + /*
> + * prepare for oversampling conversion
> + *
> + * from the datasheet:
> + * "The ACCUMULATE bit in the appropriate channel register
> + * HW_LRADC_CHn must be set to 1 if NUM_SAMPLES is greater then 0;
> + * otherwise, the IRQs will not fire."
> + */
> + mxs_lradc_reg(lradc, LRADC_CH_ACCUMULATE |
> + LRADC_CH_NUM_SAMPLES(lradc->over_sample_cnt - 1),
> + LRADC_CH(ch));
> +
> + /* from the datasheet:
> + * "Software must clear this register in preparation for a
> + * multi-cycle accumulation.
> + */
> + mxs_lradc_reg_clear(lradc, LRADC_CH_VALUE_MASK, LRADC_CH(ch));
> +
> + /* prepare the delay/loop unit according to the oversampling count */
> + mxs_lradc_reg(lradc, LRADC_DELAY_TRIGGER(1 << ch) |
> + LRADC_DELAY_TRIGGER_DELAYS(0) |
> + LRADC_DELAY_LOOP(lradc->over_sample_cnt - 1) |
> + LRADC_DELAY_DELAY(lradc->over_sample_delay - 1),
> + LRADC_DELAY(3));
> +
> + mxs_lradc_reg_clear(lradc, LRADC_CTRL1_LRADC_IRQ(2) |
> + LRADC_CTRL1_LRADC_IRQ(3) | LRADC_CTRL1_LRADC_IRQ(4) |
> + LRADC_CTRL1_LRADC_IRQ(5), LRADC_CTRL1);
> +
> + /* wake us again, when the complete conversion is done */
> + mxs_lradc_reg_set(lradc, LRADC_CTRL1_LRADC_IRQ_EN(ch), LRADC_CTRL1);
> + /*
> + * after changing the touchscreen plates setting
> + * the signals need some initial time to settle. Start the
> + * SoC's delay unit and start the conversion later
> + * and automatically.
> + */
> + mxs_lradc_reg(lradc, LRADC_DELAY_TRIGGER(0) | /* don't trigger ADC */
> + LRADC_DELAY_TRIGGER_DELAYS(1 << 3) | /* trigger DELAY unit#3 */
> + LRADC_DELAY_KICK |
> + LRADC_DELAY_DELAY(lradc->settling_delay),
> + LRADC_DELAY(2));
> +}
> +
> +/*
> + * Pressure detection is special:
> + * We want to do both required measurements for the pressure detection in
> + * one turn. Use the hardware features to chain both conversions and let the
> + * hardware report one interrupt if both conversions are done
> + */
> +static void mxs_lradc_setup_ts_pressure(struct mxs_lradc *lradc, unsigned ch1,
> + unsigned ch2)
> +{
> + u32 reg;
> +
> + /*
> + * prepare for oversampling conversion
> + *
> + * from the datasheet:
> + * "The ACCUMULATE bit in the appropriate channel register
> + * HW_LRADC_CHn must be set to 1 if NUM_SAMPLES is greater then 0;
> + * otherwise, the IRQs will not fire."
> + */
> + reg = LRADC_CH_ACCUMULATE |
> + LRADC_CH_NUM_SAMPLES(lradc->over_sample_cnt - 1);
> + mxs_lradc_reg(lradc, reg, LRADC_CH(ch1));
> + mxs_lradc_reg(lradc, reg, LRADC_CH(ch2));
> +
> + /* from the datasheet:
> + * "Software must clear this register in preparation for a
> + * multi-cycle accumulation.
> + */
> + mxs_lradc_reg_clear(lradc, LRADC_CH_VALUE_MASK, LRADC_CH(ch1));
> + mxs_lradc_reg_clear(lradc, LRADC_CH_VALUE_MASK, LRADC_CH(ch2));
> +
> + /* prepare the delay/loop unit according to the oversampling count */
> + mxs_lradc_reg(lradc, LRADC_DELAY_TRIGGER(1 << ch1) |
> + LRADC_DELAY_TRIGGER(1 << ch2) | /* start both channels */
> + LRADC_DELAY_TRIGGER_DELAYS(0) |
> + LRADC_DELAY_LOOP(lradc->over_sample_cnt - 1) |
> + LRADC_DELAY_DELAY(lradc->over_sample_delay - 1),
> + LRADC_DELAY(3));
> +
> + mxs_lradc_reg_clear(lradc, LRADC_CTRL1_LRADC_IRQ(2) |
> + LRADC_CTRL1_LRADC_IRQ(3) | LRADC_CTRL1_LRADC_IRQ(4) |
> + LRADC_CTRL1_LRADC_IRQ(5), LRADC_CTRL1);
> +
> + /* wake us again, when the conversions are done */
> + mxs_lradc_reg_set(lradc, LRADC_CTRL1_LRADC_IRQ_EN(ch2), LRADC_CTRL1);
> + /*
> + * after changing the touchscreen plates setting
> + * the signals need some initial time to settle. Start the
> + * SoC's delay unit and start the conversion later
> + * and automatically.
> + */
> + mxs_lradc_reg(lradc, LRADC_DELAY_TRIGGER(0) | /* don't trigger ADC */
> + LRADC_DELAY_TRIGGER_DELAYS(1 << 3) | /* trigger DELAY unit#3 */
> + LRADC_DELAY_KICK |
> + LRADC_DELAY_DELAY(lradc->settling_delay), LRADC_DELAY(2));
> +}
> +
> +static unsigned mxs_lradc_read_raw_channel(struct mxs_lradc *lradc,
> + unsigned channel)
> +{
> + u32 reg;
> + unsigned num_samples, val;
> +
> + reg = readl(lradc->base + LRADC_CH(channel));
> + if (reg & LRADC_CH_ACCUMULATE)
> + num_samples = lradc->over_sample_cnt;
> + else
> + num_samples = 1;
> +
> + val = (reg & LRADC_CH_VALUE_MASK) >> LRADC_CH_VALUE_OFFSET;
> + return val / num_samples;
> +}
> +
> +static unsigned mxs_lradc_read_ts_pressure(struct mxs_lradc *lradc,
> + unsigned ch1, unsigned ch2)
> +{
> + u32 reg, mask;
> + unsigned pressure, m1, m2;
> +
> + mask = LRADC_CTRL1_LRADC_IRQ(ch1) | LRADC_CTRL1_LRADC_IRQ(ch2);
> + reg = readl(lradc->base + LRADC_CTRL1) & mask;
> +
> + while (reg != mask) {
> + reg = readl(lradc->base + LRADC_CTRL1) & mask;
> + dev_dbg(lradc->dev, "One channel is still busy: %X\n", reg);
> + }
> +
> + m1 = mxs_lradc_read_raw_channel(lradc, ch1);
> + m2 = mxs_lradc_read_raw_channel(lradc, ch2);
> +
> + if (m2 == 0) {
> + dev_warn(lradc->dev, "Cannot calculate pressure\n");
> + return 1 << (LRADC_RESOLUTION - 1);
> + }
> +
> + /* simply scale the value from 0 ... max ADC resolution */
> + pressure = m1;
> + pressure *= (1 << LRADC_RESOLUTION);
> + pressure /= m2;
> +
> + dev_dbg(lradc->dev, "Pressure = %u\n", pressure);
> + return pressure;
> +}
> +
> +#define TS_CH_XP 2
> +#define TS_CH_YP 3
> +#define TS_CH_XM 4
> +#define TS_CH_YM 5
> +
> +static int mxs_lradc_read_ts_channel(struct mxs_lradc *lradc)
> +{
> + u32 reg;
> + int val;
> +
> + reg = readl(lradc->base + LRADC_CTRL1);
> +
> + /* only channels 3 to 5 are of interest here */
> + if (reg & LRADC_CTRL1_LRADC_IRQ(TS_CH_YP)) {
> + mxs_lradc_reg_clear(lradc, LRADC_CTRL1_LRADC_IRQ_EN(TS_CH_YP) |
> + LRADC_CTRL1_LRADC_IRQ(TS_CH_YP), LRADC_CTRL1);
> + val = mxs_lradc_read_raw_channel(lradc, TS_CH_YP);
> + } else if (reg & LRADC_CTRL1_LRADC_IRQ(TS_CH_XM)) {
> + mxs_lradc_reg_clear(lradc, LRADC_CTRL1_LRADC_IRQ_EN(TS_CH_XM) |
> + LRADC_CTRL1_LRADC_IRQ(TS_CH_XM), LRADC_CTRL1);
> + val = mxs_lradc_read_raw_channel(lradc, TS_CH_XM);
> + } else if (reg & LRADC_CTRL1_LRADC_IRQ(TS_CH_YM)) {
> + mxs_lradc_reg_clear(lradc, LRADC_CTRL1_LRADC_IRQ_EN(TS_CH_YM) |
> + LRADC_CTRL1_LRADC_IRQ(TS_CH_YM), LRADC_CTRL1);
> + val = mxs_lradc_read_raw_channel(lradc, TS_CH_YM);
> + } else {
> + return -EIO;
> + }
> +
> + mxs_lradc_reg(lradc, 0, LRADC_DELAY(2));
> + mxs_lradc_reg(lradc, 0, LRADC_DELAY(3));
> +
> + return val;
> +}
> +
> +/*
> + * YP(open)--+-------------+
> + * | |--+
> + * | | |
> + * YM(-)--+-------------+ |
> + * +--------------+
> + * | |
> + * XP(weak+) XM(open)
> + *
> + * "weak+" means 200k Ohm VDDIO
> + * (-) means GND
> + */
> +static void mxs_lradc_setup_touch_detection(struct mxs_lradc *lradc)
> +{
> + /*
> + * In order to detect a touch event the 'touch detect enable' bit
> + * enables:
> + * - a weak pullup to the X+ connector
> + * - a strong ground at the Y- connector
> + */
> + mxs_lradc_reg_clear(lradc, mxs_lradc_plate_mask(lradc), LRADC_CTRL0);
> + mxs_lradc_reg_set(lradc, mxs_lradc_touch_detect_bit(lradc),
> + LRADC_CTRL0);
> +}
> +
> +/*
> + * YP(meas)--+-------------+
> + * | |--+
> + * | | |
> + * YM(open)--+-------------+ |
> + * +--------------+
> + * | |
> + * XP(+) XM(-)
> + *
> + * (+) means here 1.85 V
> + * (-) means here GND
> + */
> +static void mxs_lradc_prepare_x_pos(struct mxs_lradc *lradc)
> +{
> + mxs_lradc_reg_clear(lradc, mxs_lradc_plate_mask(lradc), LRADC_CTRL0);
> + mxs_lradc_reg_set(lradc, mxs_lradc_drive_x_plate(lradc), LRADC_CTRL0);
> +
> + lradc->cur_plate = LRADC_SAMPLE_X;
> + mxs_lradc_setup_ts_channel(lradc, TS_CH_YP);
> +}
> +
> +/*
> + * YP(+)--+-------------+
> + * | |--+
> + * | | |
> + * YM(-)--+-------------+ |
> + * +--------------+
> + * | |
> + * XP(open) XM(meas)
> + *
> + * (+) means here 1.85 V
> + * (-) means here GND
> + */
> +static void mxs_lradc_prepare_y_pos(struct mxs_lradc *lradc)
> +{
> + mxs_lradc_reg_clear(lradc, mxs_lradc_plate_mask(lradc), LRADC_CTRL0);
> + mxs_lradc_reg_set(lradc, mxs_lradc_drive_y_plate(lradc), LRADC_CTRL0);
> +
> + lradc->cur_plate = LRADC_SAMPLE_Y;
> + mxs_lradc_setup_ts_channel(lradc, TS_CH_XM);
> +}
> +
> +/*
> + * YP(+)--+-------------+
> + * | |--+
> + * | | |
> + * YM(meas)--+-------------+ |
> + * +--------------+
> + * | |
> + * XP(meas) XM(-)
> + *
> + * (+) means here 1.85 V
> + * (-) means here GND
> + */
> +static void mxs_lradc_prepare_pressure(struct mxs_lradc *lradc)
> +{
> + mxs_lradc_reg_clear(lradc, mxs_lradc_plate_mask(lradc), LRADC_CTRL0);
> + mxs_lradc_reg_set(lradc, mxs_lradc_drive_pressure(lradc), LRADC_CTRL0);
> +
> + lradc->cur_plate = LRADC_SAMPLE_PRESSURE;
> + mxs_lradc_setup_ts_pressure(lradc, TS_CH_XP, TS_CH_YM);
> +}
> +
> +static void mxs_lradc_enable_touch_detection(struct mxs_lradc *lradc)
> +{
> + mxs_lradc_setup_touch_detection(lradc);
> +
> + lradc->cur_plate = LRADC_TOUCH;
> + mxs_lradc_reg_clear(lradc, LRADC_CTRL1_TOUCH_DETECT_IRQ |
> + LRADC_CTRL1_TOUCH_DETECT_IRQ_EN, LRADC_CTRL1);
> + mxs_lradc_reg_set(lradc, LRADC_CTRL1_TOUCH_DETECT_IRQ_EN, LRADC_CTRL1);
> +}
> +
> +static void mxs_lradc_report_ts_event(struct mxs_lradc *lradc)
> +{
> + input_report_abs(lradc->ts_input, ABS_X, lradc->ts_x_pos);
> + input_report_abs(lradc->ts_input, ABS_Y, lradc->ts_y_pos);
> + input_report_abs(lradc->ts_input, ABS_PRESSURE, lradc->ts_pressure);
> + input_report_key(lradc->ts_input, BTN_TOUCH, 1);
> + input_sync(lradc->ts_input);
> +}
> +
> +static void mxs_lradc_complete_touch_event(struct mxs_lradc *lradc)
> +{
> + mxs_lradc_setup_touch_detection(lradc);
> + lradc->cur_plate = LRADC_SAMPLE_VALID;
> + /*
> + * start a dummy conversion to burn time to settle the signals
> + * note: we are not interested in the conversion's value
> + */
> + mxs_lradc_reg(lradc, 0, LRADC_CH(5));
> + mxs_lradc_reg_clear(lradc, LRADC_CTRL1_LRADC_IRQ(5), LRADC_CTRL1);
> + mxs_lradc_reg_set(lradc, LRADC_CTRL1_LRADC_IRQ_EN(5), LRADC_CTRL1);
> + mxs_lradc_reg(lradc, LRADC_DELAY_TRIGGER(1 << 5) |
> + LRADC_DELAY_KICK | LRADC_DELAY_DELAY(10), /* waste 5 ms */
> + LRADC_DELAY(2));
> +}
> +
> +/*
> + * in order to avoid false measurements, report only samples where
> + * the surface is still touched after the position measurement
> + */
> +static void mxs_lradc_finish_touch_event(struct mxs_lradc *lradc, bool valid)
> +{
> + /* if it is still touched, report the sample */
> + if (valid && mxs_lradc_check_touch_event(lradc)) {
> + lradc->ts_valid = true;
> + mxs_lradc_report_ts_event(lradc);
> + }
> +
> + /* if it is even still touched, continue with the next measurement */
> + if (mxs_lradc_check_touch_event(lradc)) {
> + mxs_lradc_prepare_y_pos(lradc);
> + return;
> + }
> +
> + if (lradc->ts_valid) {
> + /* signal the release */
> + lradc->ts_valid = false;
> + input_report_key(lradc->ts_input, BTN_TOUCH, 0);
> + input_sync(lradc->ts_input);
> + }
> +
> + /* if it is released, wait for the next touch via IRQ */
> + mxs_lradc_reg_clear(lradc, LRADC_CTRL1_TOUCH_DETECT_IRQ, LRADC_CTRL1);
> + mxs_lradc_reg_set(lradc, LRADC_CTRL1_TOUCH_DETECT_IRQ_EN, LRADC_CTRL1);
> +}
> +
> +/* touchscreen's state machine */
> +static void mxs_lradc_handle_touch(struct mxs_lradc *lradc)
> +{
> + int val;
> +
> + switch (lradc->cur_plate) {
> + case LRADC_TOUCH:
> + /*
> + * start with the Y-pos, because it uses nearly the same plate
> + * settings like the touch detection
> + */
> + if (mxs_lradc_check_touch_event(lradc)) {
> + mxs_lradc_reg_clear(lradc,
> + LRADC_CTRL1_TOUCH_DETECT_IRQ_EN,
> + LRADC_CTRL1);
> + mxs_lradc_prepare_y_pos(lradc);
> + }
> + mxs_lradc_reg_clear(lradc, LRADC_CTRL1_TOUCH_DETECT_IRQ,
> + LRADC_CTRL1);
> + return;
> +
> + case LRADC_SAMPLE_Y:
> + val = mxs_lradc_read_ts_channel(lradc);
> + if (val < 0) {
> + mxs_lradc_enable_touch_detection(lradc); /* re-start */
> + return;
> + }
> + lradc->ts_y_pos = val;
> + mxs_lradc_prepare_x_pos(lradc);
> + return;
> +
> + case LRADC_SAMPLE_X:
> + val = mxs_lradc_read_ts_channel(lradc);
> + if (val < 0) {
> + mxs_lradc_enable_touch_detection(lradc); /* re-start */
> + return;
> + }
> + lradc->ts_x_pos = val;
> + mxs_lradc_prepare_pressure(lradc);
> + return;
> +
> + case LRADC_SAMPLE_PRESSURE:
> + lradc->ts_pressure =
> + mxs_lradc_read_ts_pressure(lradc, TS_CH_XP, TS_CH_YM);
> + mxs_lradc_complete_touch_event(lradc);
> + return;
> +
> + case LRADC_SAMPLE_VALID:
> + val = mxs_lradc_read_ts_channel(lradc); /* ignore the value */
> + mxs_lradc_finish_touch_event(lradc, 1);
> + break;
> + }
> +}
> +
> /*
> * Raw I/O operations
> */
> @@ -385,15 +820,6 @@ static const struct iio_info mxs_lradc_iio_info = {
> .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;
> @@ -551,10 +977,6 @@ static void mxs_lradc_ts_work(struct work_struct *ts_work)
> 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. */
> mxs_lradc_reg_clear(lradc, LRADC_CTRL1_TOUCH_DETECT_IRQ, LRADC_CTRL1);
> mxs_lradc_reg_set(lradc, LRADC_CTRL1_TOUCH_DETECT_IRQ_EN, LRADC_CTRL1);
> @@ -564,36 +986,29 @@ 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. */
> - mxs_lradc_reg_set(lradc, mxs_lradc_touch_detect_bit(lradc),
> - LRADC_CTRL0);
> -
> - /* Enable the touch-detect IRQ. */
> - mxs_lradc_reg_set(lradc, LRADC_CTRL1_TOUCH_DETECT_IRQ_EN, LRADC_CTRL1);
> + mxs_lradc_enable_touch_detection(lradc);
>
> return 0;
> }
>
> -static void mxs_lradc_ts_close(struct input_dev *dev)
> +static void mxs_lradc_disable_ts(struct mxs_lradc *lradc)
> {
> - struct mxs_lradc *lradc = input_get_drvdata(dev);
> -
> - /* Indicate the touchscreen is stopping. */
> - lradc->stop_touchscreen = true;
> - mb();
> + /* stop all interrupts from firing */
> + mxs_lradc_reg_clear(lradc, LRADC_CTRL1_TOUCH_DETECT_IRQ_EN |
> + LRADC_CTRL1_LRADC_IRQ_EN(2) | LRADC_CTRL1_LRADC_IRQ_EN(3) |
> + LRADC_CTRL1_LRADC_IRQ_EN(4) | LRADC_CTRL1_LRADC_IRQ_EN(5),
> + LRADC_CTRL1);
>
> - /* Wait until touchscreen thread finishes any possible remnants. */
> - cancel_work_sync(&lradc->ts_work);
> + /* Power-down touchscreen touch-detect circuitry. */
> + mxs_lradc_reg_clear(lradc, mxs_lradc_plate_mask(lradc), LRADC_CTRL0);
> +}
>
> - /* Disable touchscreen touch-detect IRQ. */
> - mxs_lradc_reg_clear(lradc, LRADC_CTRL1_TOUCH_DETECT_IRQ_EN,
> - LRADC_CTRL1);
> +static void mxs_lradc_ts_close(struct input_dev *dev)
> +{
> + struct mxs_lradc *lradc = input_get_drvdata(dev);
>
> - /* Power-down touchscreen touch-detect circuitry. */
> - mxs_lradc_reg_clear(lradc, mxs_lradc_touch_detect_bit(lradc), LRADC_CTRL0);
> + mxs_lradc_disable_ts(lradc);
> }
>
> static int mxs_lradc_ts_register(struct mxs_lradc *lradc)
> @@ -641,6 +1056,7 @@ static void mxs_lradc_ts_unregister(struct mxs_lradc *lradc)
>
> cancel_work_sync(&lradc->ts_work);
>
> + mxs_lradc_disable_ts(lradc);
> input_unregister_device(lradc->ts_input);
> }
>
> @@ -653,30 +1069,23 @@ static irqreturn_t mxs_lradc_handle_irq(int irq, void *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;
> + LRADC_CTRL1_TOUCH_DETECT_IRQ |
> + LRADC_CTRL1_LRADC_IRQ(2) |
> + LRADC_CTRL1_LRADC_IRQ(3) |
> + LRADC_CTRL1_LRADC_IRQ(4) |
> + LRADC_CTRL1_LRADC_IRQ(5);
>
> if (!(reg & mxs_lradc_irq_mask(lradc)))
> 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) {
> - mxs_lradc_reg_clear(lradc, ts_irq_mask, LRADC_CTRL1);
> - if (!lradc->stop_touchscreen)
> - schedule_work(&lradc->ts_work);
> - }
> + if (lradc->use_touchscreen && (reg & ts_irq_mask))
> + mxs_lradc_handle_touch(lradc);
>
> 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);
>
> - mxs_lradc_reg_clear(lradc, reg & mxs_lradc_irq_mask(lradc), LRADC_CTRL1);
> -
> return IRQ_HANDLED;
> }
>
> @@ -971,6 +1380,17 @@ static const struct of_device_id mxs_lradc_dt_ids[] = {
> };
> MODULE_DEVICE_TABLE(of, mxs_lradc_dt_ids);
>
> +static int mxs_lradc_probe_touchscreen(struct mxs_lradc *lradc,
> + struct device_node *lradc_node)
> +{
> + /* TODO retrieve from device tree */
> + lradc->over_sample_cnt = 4;
> + lradc->over_sample_delay = 2;
> + lradc->settling_delay = 10;
> +
> + return 0;
> +}
> +
> static int mxs_lradc_probe(struct platform_device *pdev)
> {
> const struct of_device_id *of_id =
> @@ -983,7 +1403,7 @@ static int mxs_lradc_probe(struct platform_device *pdev)
> struct iio_dev *iio;
> struct resource *iores;
> uint32_t ts_wires = 0;
> - int ret = 0;
> + int ret = 0, touch_ret;
> int i;
>
> /* Allocate the IIO device. */
> @@ -1003,7 +1423,7 @@ static int mxs_lradc_probe(struct platform_device *pdev)
> if (IS_ERR(lradc->base))
> return PTR_ERR(lradc->base);
>
> - INIT_WORK(&lradc->ts_work, mxs_lradc_ts_work);
> + touch_ret = mxs_lradc_probe_touchscreen(lradc, node);
>
> /* Check if touchscreen is enabled in DT. */
> ret = of_property_read_u32(node, "fsl,lradc-touchscreen-wires",
> @@ -1066,9 +1486,11 @@ static int mxs_lradc_probe(struct platform_device *pdev)
> goto err_dev;
>
> /* Register the touchscreen input device. */
> - ret = mxs_lradc_ts_register(lradc);
> - if (ret)
> - goto err_dev;
> + if (touch_ret == 0) {
> + ret = mxs_lradc_ts_register(lradc);
> + if (ret)
> + goto err_dev;
> + }
>
> /* Register IIO device. */
> ret = iio_device_register(iio);
>
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