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From: Alexandre Belloni <alexandre.belloni@bootlin.com>
To: Jonas Bonn <jonas@norrbonn.se>
Cc: Nicolas.Ferre@microchip.com, linux-kernel@vger.kernel.org,
	broonie@kernel.org, Ludovic.Desroches@microchip.com,
	linux-spi@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	Tudor.Ambarus@microchip.com
Subject: Re: [PATCH v4 2/2] spi-atmel: support inter-word delay
Date: Tue, 29 Jan 2019 16:05:49 +0100	[thread overview]
Message-ID: <20190129150549.GA19959@piout.net> (raw)
In-Reply-To: <7a6efd1a-5920-60e5-bc68-dfbe6866e522@norrbonn.se>

Hi,

On 29/01/2019 15:56:31+0100, Jonas Bonn wrote:
> On 29/01/2019 15:27, Nicolas.Ferre@microchip.com wrote:
> > On 29/01/2019 at 09:38, Jonas Bonn wrote:
> > > 
> > > +	/* DLYBCT adds delays between words.  This is useful for slow devices
> > > +	 * that need a bit of time to setup the next transfer.
> > > +	 */
> > > +	if (spi->word_delay_us) {
> > 
> > Well...
> > 
> > > +		csr |= SPI_BF(DLYBCT,
> > > +			clamp_t(u8,
> > > +				(as->spi_clk/1000000*spi->word_delay_us)>>5,
> > > +				1, 255));
> > 
> > ... why not simplifying to:
> > +				0, 255));
> > and remove the test altogether, after all?
> 
> Hmm... that seemed too easy!  This started out as something else and looking
> at it now I think even the clamp_t() is unnecessary.  The value is already
> 0-255 and the way SPI_BF works any overflow is already truncated...  I'll
> rework this and resubmit once I get some feedback on the word_delay_us bits.
> 

While at it, note that you need to add spaces around the operators.

-- 
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

      reply	other threads:[~2019-01-29 15:05 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20190129083844.20572-1-jonas@norrbonn.se>
2019-01-29  8:38 ` [PATCH v4 1/2] spi: support inter-word delay requirement for devices Jonas Bonn
2019-01-29 18:06   ` Mark Brown
2019-01-29  8:38 ` [PATCH v4 2/2] spi-atmel: support inter-word delay Jonas Bonn
2019-01-29 14:27   ` Nicolas.Ferre
2019-01-29 14:56     ` Jonas Bonn
2019-01-29 15:05       ` Alexandre Belloni [this message]

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