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SubjectRe: [PATCH v6 3/6] mfd: ti_am335x_tscadc: Remove unwanted reg_se_cache save
On Tue, 20 Jan 2015, R, Vignesh wrote:
> 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.

I have no problem with that, but is there a technical reason why?

> >> 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
> >

--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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