On Monday 03 November 2014 08:35 PM, Lee Jones wrote:
> On Mon, 27 Oct 2014, Vignesh R wrote:
>> From: Brad Griffis <bgriffis@xxxxxx>
>>
>> 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@xxxxxx>
>> [vigneshr@xxxxxx: Ported patch from v3.12 to v3.18rc2]
>> Signed-off-by: Vignesh R <vigneshr@xxxxxx>
>> ---
>> 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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