RE: [PATCH v3 3/6] mfd: ti_am335x_tscadc: Remove unwanted reg_se_cache save

From: R, Vignesh
Date: Tue Nov 11 2014 - 10:27:55 EST



On Tue, 11 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 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.
>
> Signed-off-by: Vignesh R <vigneshr@xxxxxx>
> ---

You need to provide a changelog here when submitting new versions.

I have included changelog in the cover page. Will include them in
individual patches next time.

> 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..110038859a8d
> 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) && !(reg & 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;

You didn't answer my question about this?
I did reply to the question in the previous thread.

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.

> 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 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

--
Lee Jones
Linaro STMicroelectronics Landing Team Lead Linaro.org â Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog
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