From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexandre Belloni Subject: Re: [PATCH v4 2/2] spi-atmel: support inter-word delay Date: Tue, 29 Jan 2019 16:05:49 +0100 Message-ID: <20190129150549.GA19959@piout.net> References: <20190129083844.20572-1-jonas@norrbonn.se> <20190129083844.20572-3-jonas@norrbonn.se> <995b3885-254b-7932-8d05-77271a2c070d@microchip.com> <7a6efd1a-5920-60e5-bc68-dfbe6866e522@norrbonn.se> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii 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 To: Jonas Bonn Return-path: Content-Disposition: inline In-Reply-To: <7a6efd1a-5920-60e5-bc68-dfbe6866e522@norrbonn.se> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-spi.vger.kernel.org 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