linux-kernel - Re: [PATCH v2] spi: omap2-mcspi: Add support for GPIO chipselects

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Message-ID: <553F9359.2010901@imgtec.com>
Date:	Tue, 28 Apr 2015 11:04:09 -0300
From:	Ezequiel Garcia <ezequiel.garcia@...tec.com>
To:	Michael Welling <mwelling@...e.org>
CC:	Mark Brown <broonie@...nel.org>, <linux-spi@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] spi: omap2-mcspi: Add support for GPIO chipselects

On 04/27/2015 10:21 PM, Michael Welling wrote:
> On Mon, Apr 27, 2015 at 08:55:50PM +0100, Mark Brown wrote:
>> On Sun, Apr 26, 2015 at 10:44:30PM -0500, Michael Welling wrote:
>>
>>> +	if (gpio_is_valid(spi->cs_gpio)) {
>>> +		gpio_set_value(spi->cs_gpio, (cs_active) ?
>>> +			!!(spi->mode & SPI_CS_HIGH) :
>>> +			!(spi->mode & SPI_CS_HIGH));
>>> +	}
>>
>> Two problems here.  One is that the above logic statement is just not
>> readable (the repitition of hecks, the ternery operator, the
>> indentation...) and the other is that the core chipselect support
>> already handles GPIO chipselects so you should really be converting the
>> driver to use that.  At the very least the code needs to be legible
>> though.
> 
> Before I send another patch how does this look?
> 
> 	if (gpio_is_valid(spi->cs_gpio)) {
> 		if (cs_active)
> 			gpio_set_value(spi->cs_gpio, spi->mode & SPI_CS_HIGH);
> 		else
> 			gpio_set_value(spi->cs_gpio, !(spi->mode & SPI_CS_HIGH));
> 	}
> 
> If I were to attempt to convert the driver to use the core chipselect support,
> how would I go about doing it?
> 
> Is there another driver that I can use for reference?

We've recently done that for spi-img-spfi.c.

-- 
Ezequiel
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