Subject: [PATCH 3/5] mfd: ti_am335x_tscadc: Remove unwanted reg_se_cache save

From: [email-masked] (Lee Jones)
Date: Mon, 10 Nov 2014 09:15:27 +0000

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
> 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 <[email-masked]>
> ---
>  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)
>  		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 & (!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).

>  		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;
>  	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 ? Open source software for ARM SoCs
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