linux-kernel - Re: [PATCH 3/3] iio: stmpe-adc: Enable all stmpe-adc interrupts just once

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Date:   Sun, 5 May 2019 16:45:03 +0100
From:   Jonathan Cameron <jic23@...nel.org>
To:     Philippe Schenker <dev@...henker.ch>
Cc:     linux-iio@...r.kernel.org, Stefan Agner <stefan@...er.ch>,
        Hartmut Knaack <knaack.h@....de>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Peter Meerwald-Stadler <pmeerw@...erw.net>,
        Philippe Schenker <philippe.schenker@...adex.com>,
        Max Krummenacher <max.krummenacher@...adex.com>,
        Alexandre Torgue <alexandre.torgue@...com>,
        linux-kernel@...r.kernel.org, Lee Jones <lee.jones@...aro.org>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        linux-stm32@...md-mailman.stormreply.com,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 3/3] iio: stmpe-adc: Enable all stmpe-adc interrupts
 just once

On Fri,  3 May 2019 15:57:25 +0200
Philippe Schenker <dev@...henker.ch> wrote:

> From: Philippe Schenker <philippe.schenker@...adex.com>
> 
> This commit will enable the interrupts of all channels handled by this
> driver only once in the probe function.
> 
> This will improve performance because one byte less has to be written over
> i2c on each read out of the adc. On the fastest ADC mode this will improve
> read out speed by 15%.
> 
> Signed-off-by: Philippe Schenker <philippe.schenker@...adex.com>
Makes sense. I'll pick this up once patch 2 discussion is sorted.

Jonathan

> 
> ---
> 
>  drivers/iio/adc/stmpe-adc.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/iio/adc/stmpe-adc.c b/drivers/iio/adc/stmpe-adc.c
> index baa41ffc0d76..427c890c6e7d 100644
> --- a/drivers/iio/adc/stmpe-adc.c
> +++ b/drivers/iio/adc/stmpe-adc.c
> @@ -72,9 +72,6 @@ static int stmpe_read_voltage(struct stmpe_adc *info,
>  		return -EINVAL;
>  	}
>  
> -	stmpe_reg_write(info->stmpe, STMPE_REG_ADC_INT_EN,
> -			STMPE_ADC_CH(info->channel));
> -
>  	stmpe_reg_write(info->stmpe, STMPE_REG_ADC_CAPT,
>  			STMPE_ADC_CH(info->channel));
>  
> @@ -328,6 +325,9 @@ static int stmpe_adc_probe(struct platform_device *pdev)
>  	if (ret)
>  		return ret;
>  
> +	stmpe_reg_write(info->stmpe, STMPE_REG_ADC_INT_EN,
> +			~(norequest_mask & 0xFF));
> +
>  	return devm_iio_device_register(&pdev->dev, indio_dev);
>  }
>