Vignesh R schrieb am 27.10.2014 12:08:
> From: Brad Griffis <bgrif...@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 <bgrif...@ti.com>
> [vigne...@ti.com: Ported the patch from v3.12 to v3.18rc2]
> Signed-off-by: Vignesh R <vigne...@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;
You could even initialize it with zero during variable definition. And I think 
the above comment could need an update now.
>       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;
>               }
>       }
>  }
> 

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