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Input: ti_am335x_tsc - remove udelay in interrupt handler 

TSC interrupt handler had udelay to avoid reporting of false pen-up
interrupt to user space. This patch implements workaround suggesting in
Advisory 1.0.31 of silicon errata for am335x, thus eliminating udelay and
touchscreen lag. This also improves performance of touchscreen and
eliminates sudden jump of cursor at touch release.

IDLECONFIG and CHARGECONFIG registers are to be configured with same values
in order to eliminate false pen-up events. This workaround may result in
false pen-down to be detected, hence considerable charge step delay needs
to be added. The charge delay is set to 0xB000 (in terms of ADC clock
cycles) by default.

TSC steps are disabled at the end of every sampling cycle and EOS bit is
set. Once the EOS bit is set, the TSC steps need to be re-enabled to begin
next sampling cycle.

Signed-off-by: Brad Griffis <bgriffis@ti.com>
[vigneshr@ti.com: Ported the patch from v3.12 to v3.19rc1]
Signed-off-by: Vignesh R <vigneshr@ti.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
This commit is contained in:
Brad Griffis 2015-02-03 11:44:12 -08:00 committed by Dmitry Torokhov
parent 3a59684ccc
commit 344d635b9a
2 changed files with 33 additions and 37 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

67
drivers/input/touchscreen/ti_am335x_tsc.c
View File

@ -173,11 +173,9 @@ static void titsc_step_config(struct titsc *ts_dev)
titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY);
}
/* Charge step configuration */
config = ts_dev->bit_xp | ts_dev->bit_yn |
STEPCHARGE_RFP_XPUL | STEPCHARGE_RFM_XNUR |
STEPCHARGE_INM_AN1 | STEPCHARGE_INP(ts_dev->inp_yp);
/* Make CHARGECONFIG same as IDLECONFIG */
config = titsc_readl(ts_dev, REG_IDLECONFIG);
titsc_writel(ts_dev, REG_CHARGECONFIG, config);
titsc_writel(ts_dev, REG_CHARGEDELAY, CHARGEDLY_OPENDLY);
@ -261,12 +259,34 @@ static irqreturn_t titsc_irq(int irq, void *dev)
{
struct titsc *ts_dev = dev;
struct input_dev *input_dev = ts_dev->input;
unsigned int status, irqclr = 0;
unsigned int fsm, status, irqclr = 0;
unsigned int x = 0, y = 0;
unsigned int z1, z2, z;
unsigned int fsm;
status = titsc_readl(ts_dev, REG_IRQSTATUS);
status = titsc_readl(ts_dev, REG_RAWIRQSTATUS);
if (status & IRQENB_HW_PEN) {
ts_dev->pen_down = true;
titsc_writel(ts_dev, REG_IRQWAKEUP, 0x00);
titsc_writel(ts_dev, REG_IRQCLR, IRQENB_HW_PEN);
irqclr |= IRQENB_HW_PEN;
}
if (status & IRQENB_PENUP) {
fsm = titsc_readl(ts_dev, REG_ADCFSM);
if (fsm == ADCFSM_STEPID) {
ts_dev->pen_down = false;
input_report_key(input_dev, BTN_TOUCH, 0);
input_report_abs(input_dev, ABS_PRESSURE, 0);
input_sync(input_dev);
} else {
ts_dev->pen_down = true;
}
irqclr |= IRQENB_PENUP;
}
if (status & IRQENB_EOS)
irqclr |= IRQENB_EOS;
/*
* ADC and touchscreen share the IRQ line.
* FIFO1 interrupts are used by ADC. Handle FIFO0 IRQs here only
@ -297,37 +317,11 @@ static irqreturn_t titsc_irq(int irq, void *dev)
}
irqclr |= IRQENB_FIFO0THRES;
}
/*
* Time for sequencer to settle, to read
* correct state of the sequencer.
*/
udelay(SEQ_SETTLE);
status = titsc_readl(ts_dev, REG_RAWIRQSTATUS);
if (status & IRQENB_PENUP) {
/* Pen up event */
fsm = titsc_readl(ts_dev, REG_ADCFSM);
if (fsm == ADCFSM_STEPID) {
ts_dev->pen_down = false;
input_report_key(input_dev, BTN_TOUCH, 0);
input_report_abs(input_dev, ABS_PRESSURE, 0);
input_sync(input_dev);
} else {
ts_dev->pen_down = true;
}
irqclr |= IRQENB_PENUP;
}
if (status & IRQENB_HW_PEN) {
titsc_writel(ts_dev, REG_IRQWAKEUP, 0x00);
titsc_writel(ts_dev, REG_IRQCLR, IRQENB_HW_PEN);
}
if (irqclr) {
titsc_writel(ts_dev, REG_IRQSTATUS, irqclr);
am335x_tsc_se_set_cache(ts_dev->mfd_tscadc, ts_dev->step_mask);
if (status & IRQENB_EOS)
am335x_tsc_se_set_cache(ts_dev->mfd_tscadc,
ts_dev->step_mask);
return IRQ_HANDLED;
}
return IRQ_NONE;
@ -417,6 +411,7 @@ static int titsc_probe(struct platform_device *pdev)
}
titsc_writel(ts_dev, REG_IRQENABLE, IRQENB_FIFO0THRES);
titsc_writel(ts_dev, REG_IRQENABLE, IRQENB_EOS);
err = titsc_config_wires(ts_dev);
if (err) {
dev_err(&pdev->dev, "wrong i/p wire configuration\n");

3
include/linux/mfd/ti_am335x_tscadc.h
View File

@ -52,6 +52,7 @@
/* IRQ enable */
#define IRQENB_HW_PEN BIT(0)
#define IRQENB_EOS BIT(1)
#define IRQENB_FIFO0THRES BIT(2)
#define IRQENB_FIFO0OVRRUN BIT(3)
#define IRQENB_FIFO0UNDRFLW BIT(4)
@ -107,7 +108,7 @@
/* Charge delay */
#define CHARGEDLY_OPEN_MASK (0x3FFFF << 0)
#define CHARGEDLY_OPEN(val) ((val) << 0)
#define CHARGEDLY_OPENDLY CHARGEDLY_OPEN(1)
#define CHARGEDLY_OPENDLY CHARGEDLY_OPEN(0x400)
/* Control register */
#define CNTRLREG_TSCSSENB BIT(0)