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SubjectRe: [PATCH v6 3/6] mfd: ti_am335x_tscadc: Remove unwanted reg_se_cache save


On 1/20/2015 5:23 PM, Lee Jones wrote:
> On Wed, 07 Jan 2015, 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
>> stage.
>> 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.
>> TSC steps are always disabled at the end of each conversion cycle, hence
>> there is no need to explicitly disable TSC steps by writing 0 to REG_SE.
>>
>> Signed-off-by: Vignesh R <vigneshr@ti.com>
>> ---
>>
>> v5:
>> - Remove unnecessary clearing of REG_SE
>>
>> drivers/mfd/ti_am335x_tscadc.c | 13 +++++--------
>> include/linux/mfd/ti_am335x_tscadc.h | 1 +
>> 2 files changed, 6 insertions(+), 8 deletions(-)
>
> Looks fine.
>
> For my own reference:
> Acked-by: Lee Jones <lee.jones@linaro.org>
>
> Can this patch be applied on its own?
>

I prefer to wait until input patches are picked up.

>> diff --git a/drivers/mfd/ti_am335x_tscadc.c b/drivers/mfd/ti_am335x_tscadc.c
>> index 467c80e1c4ae..e4e4b22eebc9 100644
>> --- a/drivers/mfd/ti_am335x_tscadc.c
>> +++ b/drivers/mfd/ti_am335x_tscadc.c
>> @@ -68,12 +68,6 @@ static void am335x_tscadc_need_adc(struct ti_tscadc_dev *tsadc)
>> DEFINE_WAIT(wait);
>> u32 reg;
>>
>> - /*
>> - * disable TSC steps so it does not run while the ADC is using it. If
>> - * write 0 while it is running (it just started or was already running)
>> - * then it completes all steps that were enabled and stops then.
>> - */
>> - tscadc_writel(tsadc, REG_SE, 0);
>> reg = tscadc_readl(tsadc, REG_ADCFSM);
>> if (reg & SEQ_STATUS) {
>> tsadc->adc_waiting = true;
>> @@ -86,8 +80,12 @@ 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) && !(reg & CHARGE_STEP));
>> tsadc->adc_waiting = false;
>> }
>> tsadc->adc_in_use = true;
>> @@ -96,7 +94,6 @@ 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 3f4e994ace2b..1fd50dcfe47c 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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