[2/4] input: touchscreen: ti_am335x_tsc: Remove udelay in interrupt handler
diff mbox

Message ID 1414408111-2631-3-git-send-email-vigneshr@ti.com
State New, archived
Headers show

Commit Message

Vignesh Raghavendra Oct. 27, 2014, 11:08 a.m. UTC
From: Brad Griffis <bgriffis@ti.com>

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.

In one shot mode, sequencer automatically disables all enabled steps at
the end of each cycle. (both ADC steps and TSC steps) Hence these steps
need not be saved in reg_se_cache for clearing these steps at a later
stage.

Signed-off-by: Brad Griffis <bgriffis@ti.com>
[vigneshr@ti.com: Ported patch from v3.12 to v3.18rc2]
Signed-off-by: Vignesh R <vigneshr@ti.com>
---
 drivers/input/touchscreen/ti_am335x_tsc.c | 56 ++++++++++++-------------------
 drivers/mfd/ti_am335x_tscadc.c            |  7 ++--
 include/linux/mfd/ti_am335x_tscadc.h      |  4 ++-
 3 files changed, 30 insertions(+), 37 deletions(-)

Comments

Lee Jones Nov. 3, 2014, 3:05 p.m. UTC | #1
On Mon, 27 Oct 2014, Vignesh R wrote:
> From: Brad Griffis <bgriffis@ti.com>
> 
> 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.
> 
> In one shot mode, sequencer automatically disables all enabled steps at
> the end of each cycle. (both ADC steps and TSC steps) Hence these steps
> need not be saved in reg_se_cache for clearing these steps at a later
> stage.
> 
> Signed-off-by: Brad Griffis <bgriffis@ti.com>
> [vigneshr@ti.com: Ported patch from v3.12 to v3.18rc2]
> Signed-off-by: Vignesh R <vigneshr@ti.com>
> ---
>  drivers/input/touchscreen/ti_am335x_tsc.c | 56 ++++++++++++-------------------
>  drivers/mfd/ti_am335x_tscadc.c            |  7 ++--
>  include/linux/mfd/ti_am335x_tscadc.h      |  4 ++-
>  3 files changed, 30 insertions(+), 37 deletions(-)

[...]

> diff --git a/drivers/mfd/ti_am335x_tscadc.c b/drivers/mfd/ti_am335x_tscadc.c
> index d877e777cce6..94ef8992f46b 100644
> --- a/drivers/mfd/ti_am335x_tscadc.c
> +++ b/drivers/mfd/ti_am335x_tscadc.c
> @@ -86,8 +86,12 @@ static void am335x_tscadc_need_adc(struct ti_tscadc_dev *tsadc)
>  		spin_lock_irq(&tsadc->reg_lock);
>  		finish_wait(&tsadc->reg_se_wait, &wait);
>  
> +		/*
> +		 * Sequencer should either be idle or
> +		 * busy applying the charge step.
> +		 */
>  		reg = tscadc_readl(tsadc, REG_ADCFSM);
> -		WARN_ON(reg & SEQ_STATUS);
> +		WARN_ON(reg & SEQ_STATUS & (!CHARGE_STEP));
>  		tsadc->adc_waiting = false;
>  	}
>  	tsadc->adc_in_use = true;
> @@ -96,7 +100,6 @@ static void am335x_tscadc_need_adc(struct ti_tscadc_dev *tsadc)
>  void am335x_tsc_se_set_once(struct ti_tscadc_dev *tsadc, u32 val)
>  {
>  	spin_lock_irq(&tsadc->reg_lock);
> -	tsadc->reg_se_cache |= val;
>  	am335x_tscadc_need_adc(tsadc);
>  
>  	tscadc_writel(tsadc, REG_SE, val);

I believe all of these changes can, and therefor should live in a
separate patch.

> diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h
> index e2e70053470e..fcce182e4a35 100644
> --- a/include/linux/mfd/ti_am335x_tscadc.h
> +++ b/include/linux/mfd/ti_am335x_tscadc.h
> @@ -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(0xB000)
>  
>  /* Control register */
>  #define CNTRLREG_TSCSSENB	BIT(0)
> @@ -127,6 +128,7 @@
>  
>  /* Sequencer Status */
>  #define SEQ_STATUS BIT(5)
> +#define CHARGE_STEP		0x11
>  
>  #define ADC_CLK			3000000
>  #define TOTAL_STEPS		16

The header changes should be split between the two Input and MFD
patches.
Vignesh Raghavendra Nov. 7, 2014, 5:48 a.m. UTC | #2
On Monday 03 November 2014 08:35 PM, Lee Jones wrote:
> On Mon, 27 Oct 2014, Vignesh R wrote:
>> From: Brad Griffis <bgriffis@ti.com>
>>
>> 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.
>>
>> In one shot mode, sequencer automatically disables all enabled steps at
>> the end of each cycle. (both ADC steps and TSC steps) Hence these steps
>> need not be saved in reg_se_cache for clearing these steps at a later
>> stage.
>>
>> Signed-off-by: Brad Griffis <bgriffis@ti.com>
>> [vigneshr@ti.com: Ported patch from v3.12 to v3.18rc2]
>> Signed-off-by: Vignesh R <vigneshr@ti.com>
>> ---
>>  drivers/input/touchscreen/ti_am335x_tsc.c | 56 ++++++++++++-------------------
>>  drivers/mfd/ti_am335x_tscadc.c            |  7 ++--
>>  include/linux/mfd/ti_am335x_tscadc.h      |  4 ++-
>>  3 files changed, 30 insertions(+), 37 deletions(-)
> 
> [...]
> 
>> diff --git a/drivers/mfd/ti_am335x_tscadc.c b/drivers/mfd/ti_am335x_tscadc.c
>> index d877e777cce6..94ef8992f46b 100644
>> --- a/drivers/mfd/ti_am335x_tscadc.c
>> +++ b/drivers/mfd/ti_am335x_tscadc.c
>> @@ -86,8 +86,12 @@ static void am335x_tscadc_need_adc(struct ti_tscadc_dev *tsadc)
>>  		spin_lock_irq(&tsadc->reg_lock);
>>  		finish_wait(&tsadc->reg_se_wait, &wait);
>>  
>> +		/*
>> +		 * Sequencer should either be idle or
>> +		 * busy applying the charge step.
>> +		 */
>>  		reg = tscadc_readl(tsadc, REG_ADCFSM);
>> -		WARN_ON(reg & SEQ_STATUS);
>> +		WARN_ON(reg & SEQ_STATUS & (!CHARGE_STEP));
>>  		tsadc->adc_waiting = false;
>>  	}
>>  	tsadc->adc_in_use = true;
>> @@ -96,7 +100,6 @@ static void am335x_tscadc_need_adc(struct ti_tscadc_dev *tsadc)
>>  void am335x_tsc_se_set_once(struct ti_tscadc_dev *tsadc, u32 val)
>>  {
>>  	spin_lock_irq(&tsadc->reg_lock);
>> -	tsadc->reg_se_cache |= val;
>>  	am335x_tscadc_need_adc(tsadc);
>>  
>>  	tscadc_writel(tsadc, REG_SE, val);
> 
> I believe all of these changes can, and therefor should live in a
> separate patch.

I will split this patch accordingly.

> 
>> diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h
>> index e2e70053470e..fcce182e4a35 100644
>> --- a/include/linux/mfd/ti_am335x_tscadc.h
>> +++ b/include/linux/mfd/ti_am335x_tscadc.h
>> @@ -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(0xB000)
>>  
>>  /* Control register */
>>  #define CNTRLREG_TSCSSENB	BIT(0)
>> @@ -127,6 +128,7 @@
>>  
>>  /* Sequencer Status */
>>  #define SEQ_STATUS BIT(5)
>> +#define CHARGE_STEP		0x11
>>  
>>  #define ADC_CLK			3000000
>>  #define TOTAL_STEPS		16
> 
> The header changes should be split between the two Input and MFD
> patches.
> 
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Patch
diff mbox

diff --git a/drivers/input/touchscreen/ti_am335x_tsc.c b/drivers/input/touchscreen/ti_am335x_tsc.c
index 1aeac9675fe7..483fd97c0e0c 100644
--- a/drivers/input/touchscreen/ti_am335x_tsc.c
+++ b/drivers/input/touchscreen/ti_am335x_tsc.c
@@ -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);
 
@@ -264,9 +262,26 @@  static irqreturn_t titsc_irq(int irq, void *dev)
 	unsigned int 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) {
+		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);
+		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
@@ -297,34 +312,6 @@  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);
@@ -417,6 +404,7 @@  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");
diff --git a/drivers/mfd/ti_am335x_tscadc.c b/drivers/mfd/ti_am335x_tscadc.c
index d877e777cce6..94ef8992f46b 100644
--- a/drivers/mfd/ti_am335x_tscadc.c
+++ b/drivers/mfd/ti_am335x_tscadc.c
@@ -86,8 +86,12 @@  static void am335x_tscadc_need_adc(struct ti_tscadc_dev *tsadc)
 		spin_lock_irq(&tsadc->reg_lock);
 		finish_wait(&tsadc->reg_se_wait, &wait);
 
+		/*
+		 * Sequencer should either be idle or
+		 * busy applying the charge step.
+		 */
 		reg = tscadc_readl(tsadc, REG_ADCFSM);
-		WARN_ON(reg & SEQ_STATUS);
+		WARN_ON(reg & SEQ_STATUS & (!CHARGE_STEP));
 		tsadc->adc_waiting = false;
 	}
 	tsadc->adc_in_use = true;
@@ -96,7 +100,6 @@  static void am335x_tscadc_need_adc(struct ti_tscadc_dev *tsadc)
 void am335x_tsc_se_set_once(struct ti_tscadc_dev *tsadc, u32 val)
 {
 	spin_lock_irq(&tsadc->reg_lock);
-	tsadc->reg_se_cache |= val;
 	am335x_tscadc_need_adc(tsadc);
 
 	tscadc_writel(tsadc, REG_SE, val);
diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h
index e2e70053470e..fcce182e4a35 100644
--- a/include/linux/mfd/ti_am335x_tscadc.h
+++ b/include/linux/mfd/ti_am335x_tscadc.h
@@ -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(0xB000)
 
 /* Control register */
 #define CNTRLREG_TSCSSENB	BIT(0)
@@ -127,6 +128,7 @@ 
 
 /* Sequencer Status */
 #define SEQ_STATUS BIT(5)
+#define CHARGE_STEP		0x11
 
 #define ADC_CLK			3000000
 #define TOTAL_STEPS		16