[PATCH 3/5] mfd: ti_am335x_tscadc: Remove unwanted reg_se_cache save
vigneshr at ti.com
Mon Nov 10 02:44:53 PST 2014
On Monday 10 November 2014 02:56 PM, Lee Jones wrote:
> On Mon, 10 Nov 2014, Lee Jones wrote:
>> On Fri, 07 Nov 2014, Vignesh R wrote:
>>> 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
>>> Also, when ADC wakes up Sequencer should not be busy executing any of the
>>> config steps except for the charge step. Previously charge step was 1 ADC
>>> clock cycle and hence it was ignored.
>>> Signed-off-by: Vignesh R <vigneshr at ti.com>
>>> drivers/mfd/ti_am335x_tscadc.c | 7 +++++--
>>> include/linux/mfd/ti_am335x_tscadc.h | 1 +
>>> 2 files changed, 6 insertions(+), 2 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)
>>> 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));
>> This is almost certainly not correct.
>> Please take another look at the logic.
>> I'm _assuming_ you mean (reg & SEQ_STATUS && !CHARGE_STEP).
> So I just saw that CHARGE_STEP is actually the new macro below.
> So you're currently ANDing these together.
> xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx reg
> 00000000 00000000 00000000 00100000 #define SEQ_STATUS BIT(5)
> 00000000 00000000 00000000 00010001 #define CHARGE_STEP 0x11
> ... which will always equate to 0.
Oops.. Sorry.. I meant ((reg & SEQ_STATUS) && !(reg & CHARGE_STEP)).
I will fix this.
>>> 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)
>>> - tsadc->reg_se_cache |= val;
> Didn't you add this line a little over 1 month ago?
> Why the change of heart?
Previously, TSC did not reliably re-enable its steps as the TSC irq
handler received false pen up events. Hence, in order to use TSC after
ADC operation, it was necessary to save and re-enable TSC steps
(basically, to keep TSC steps enabled always).
The change was more of a workaround to overcome limitation of TSC irq
handler. With this series of patches, TSC irq handler is very reliable
and the workaround is no longer required.
>>> 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 c99be5dc0f5c..fcce182e4a35 100644
>>> --- a/include/linux/mfd/ti_am335x_tscadc.h
>>> +++ b/include/linux/mfd/ti_am335x_tscadc.h
>>> @@ -128,6 +128,7 @@
>>> /* Sequencer Status */
>>> #define SEQ_STATUS BIT(5)
>>> +#define CHARGE_STEP 0x11
>>> #define ADC_CLK 3000000
>>> #define TOTAL_STEPS 16
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