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    Subject[PATCH 1/4] input: touchscreen: ti_am335x_tsc Interchange touchscreen and ADC steps
    Date
    From: Brad Griffis <bgriffis@ti.com>

    This patch makes the initial changes required to workaround TSC-false
    pen-up interrupts. It is required to implement these changes in order to
    remove udelay in the TSC interrupt handler and false pen-up events.
    The charge step is to be executed immediately after sampling X+. Hence
    TSC is made to use higher numbered steps (steps 5 to 16 for 5 co-ordinate
    readouts, 4 wire TSC configuration) and ADC to use lower ones. Further
    X co-ordinate readouts must be the last to be sampled, thus co-ordinates
    are sampled in the order Y-Z-X.

    Signed-off-by: Brad Griffis <bgriffis@ti.com>
    [vigneshr@ti.com: Ported the patch from v3.12 to v3.18rc2]
    Signed-off-by: Vignesh R <vigneshr@ti.com>
    ---
    drivers/iio/adc/ti_am335x_adc.c | 2 +-
    drivers/input/touchscreen/ti_am335x_tsc.c | 42 ++++++++++++++++++-------------
    2 files changed, 25 insertions(+), 19 deletions(-)

    diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
    index b730864731e8..3f530ed6bd80 100644
    --- a/drivers/iio/adc/ti_am335x_adc.c
    +++ b/drivers/iio/adc/ti_am335x_adc.c
    @@ -98,7 +98,7 @@ static void tiadc_step_config(struct iio_dev *indio_dev)
    * needs to be given to ADC to digitalize data.
    */

    - steps = TOTAL_STEPS - adc_dev->channels;
    + steps = 0;
    if (iio_buffer_enabled(indio_dev))
    stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1
    | STEPCONFIG_MODE_SWCNT;
    diff --git a/drivers/input/touchscreen/ti_am335x_tsc.c b/drivers/input/touchscreen/ti_am335x_tsc.c
    index 2ce649520fe0..1aeac9675fe7 100644
    --- a/drivers/input/touchscreen/ti_am335x_tsc.c
    +++ b/drivers/input/touchscreen/ti_am335x_tsc.c
    @@ -121,7 +121,7 @@ static void titsc_step_config(struct titsc *ts_dev)
    {
    unsigned int config;
    int i;
    - int end_step;
    + int end_step, first_step, tsc_steps;
    u32 stepenable;

    config = STEPCONFIG_MODE_HWSYNC |
    @@ -140,9 +140,11 @@ static void titsc_step_config(struct titsc *ts_dev)
    break;
    }

    - /* 1 … coordinate_readouts is for X */
    - end_step = ts_dev->coordinate_readouts;
    - for (i = 0; i < end_step; i++) {
    + tsc_steps = ts_dev->coordinate_readouts * 2 + 2;
    + first_step = TOTAL_STEPS - tsc_steps;
    + /* Steps 16 to 16-coordinate_readouts is for X */
    + end_step = first_step + tsc_steps;
    + for (i = end_step - ts_dev->coordinate_readouts; i < end_step; i++) {
    titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
    titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY);
    }
    @@ -164,9 +166,9 @@ static void titsc_step_config(struct titsc *ts_dev)
    break;
    }

    - /* coordinate_readouts … coordinate_readouts * 2 is for Y */
    - end_step = ts_dev->coordinate_readouts * 2;
    - for (i = ts_dev->coordinate_readouts; i < end_step; i++) {
    + /* 1 ... coordinate_readouts is for Y */
    + end_step = first_step + ts_dev->coordinate_readouts;
    + for (i = first_step; i < end_step; i++) {
    titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
    titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY);
    }
    @@ -179,7 +181,7 @@ static void titsc_step_config(struct titsc *ts_dev)
    titsc_writel(ts_dev, REG_CHARGECONFIG, config);
    titsc_writel(ts_dev, REG_CHARGEDELAY, CHARGEDLY_OPENDLY);

    - /* coordinate_readouts * 2 … coordinate_readouts * 2 + 2 is for Z */
    + /* coordinate_readouts + 1 ... coordinate_readouts + 2 is for Z */
    config = STEPCONFIG_MODE_HWSYNC |
    STEPCONFIG_AVG_16 | ts_dev->bit_yp |
    ts_dev->bit_xn | STEPCONFIG_INM_ADCREFM |
    @@ -194,8 +196,11 @@ static void titsc_step_config(struct titsc *ts_dev)
    titsc_writel(ts_dev, REG_STEPDELAY(end_step),
    STEPCONFIG_OPENDLY);

    - /* The steps1 … end and bit 0 for TS_Charge */
    - stepenable = (1 << (end_step + 2)) - 1;
    + /* The steps end ... end - readouts * 2 + 2 and bit 0 for TS_Charge */
    + stepenable = 1;
    + for (i = 0; i < tsc_steps; i++)
    + stepenable |= 1 << (first_step + i + 1);
    +
    ts_dev->step_mask = stepenable;
    am335x_tsc_se_set_cache(ts_dev->mfd_tscadc, ts_dev->step_mask);
    }
    @@ -209,6 +214,7 @@ static void titsc_read_coordinates(struct titsc *ts_dev,
    unsigned int read, diff;
    unsigned int i, channel;
    unsigned int creads = ts_dev->coordinate_readouts;
    + unsigned int first_step = TOTAL_STEPS - (creads * 2 + 2);

    *z1 = *z2 = 0;
    if (fifocount % (creads * 2 + 2))
    @@ -226,7 +232,7 @@ static void titsc_read_coordinates(struct titsc *ts_dev,

    channel = (read & 0xf0000) >> 16;
    read &= 0xfff;
    - if (channel < creads) {
    + if (channel > first_step + creads + 2) {
    diff = abs(read - prev_val_x);
    if (diff < prev_diff_x) {
    prev_diff_x = diff;
    @@ -234,19 +240,19 @@ static void titsc_read_coordinates(struct titsc *ts_dev,
    }
    prev_val_x = read;

    - } else if (channel < creads * 2) {
    + } else if (channel == first_step + creads + 1) {
    + *z1 = read;
    +
    + } else if (channel == first_step + creads + 2) {
    + *z2 = read;
    +
    + } else if (channel > first_step) {
    diff = abs(read - prev_val_y);
    if (diff < prev_diff_y) {
    prev_diff_y = diff;
    *y = read;
    }
    prev_val_y = read;
    -
    - } else if (channel < creads * 2 + 1) {
    - *z1 = read;
    -
    - } else if (channel < creads * 2 + 2) {
    - *z2 = read;
    }
    }
    }
    --
    1.9.1
    --
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