Subject: [PATCH 1/4] input: touchscreen: ti_am335x_tsc Interchange touchscreen and ADC steps

From: [email-masked] (Hartmut Knaack)
Date: Fri, 31 Oct 2014 22:03:49 +0100

Vignesh R schrieb am 27.10.2014 12:08:
> From: Brad Griffis <[email-masked]>
> 
> 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 <[email-masked]>
> [vigneshr at ti.com: Ported the patch from v3.12 to v3.18rc2]
> Signed-off-by: Vignesh R <[email-masked]>
> ---
>  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;
>  		}
>  	}
>  }
>