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

> 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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