From: Trent Piepho <tpiepho@impinj.com>
To: "linux-spi@vger.kernel.org" <linux-spi@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"phil@raspberrypi.org" <phil@raspberrypi.org>,
"broonie@kernel.org" <broonie@kernel.org>
Subject: Re: [PATCH] spi: Make GPIO CSs honour the SPI_NO_CS flag
Date: Mon, 15 Oct 2018 18:34:18 +0000 [thread overview]
Message-ID: <1539628457.30311.5.camel@impinj.com> (raw)
In-Reply-To: <1539336198-84179-1-git-send-email-phil@raspberrypi.org>
On Fri, 2018-10-12 at 10:23 +0100, Phil Elwell wrote:
> The SPI configuration state includes an SPI_NO_CS flag that disables
> all CS line manipulation, for applications that want to manage their
> own chip selects. However, this flag is ignored by the GPIO CS code
> in the SPI framework.
> @@ -729,7 +729,9 @@ static void spi_set_cs(struct spi_device *spi, bool enable)
> enable = !enable;
>
> if (gpio_is_valid(spi->cs_gpio)) {
> - gpio_set_value(spi->cs_gpio, !enable);
> + /* Honour the SPI_NO_CS flag */
> + if (!(spi->mode & SPI_NO_CS))
> + gpio_set_value(spi->cs_gpio, !enable);
> /* Some SPI masters need both GPIO CS & slave_select */
> if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&
> spi->controller->set_cs)
What about the calls to spi->controller->set_cs() after this? Should a
driver provided set_cs method be responsible for checking SPI_NO_CS?
Or should it not be called in the first place?
I imagine it depends on what set_cs needs to do, which might not be
solely related to changing the CS line.
next prev parent reply other threads:[~2018-10-15 18:34 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-12 9:23 [PATCH] spi: Make GPIO CSs honour the SPI_NO_CS flag Phil Elwell
2018-10-12 17:03 ` Applied "spi: Make GPIO CSs honour the SPI_NO_CS flag" to the spi tree Mark Brown
2018-10-15 18:34 ` Trent Piepho [this message]
2018-10-16 9:03 ` [PATCH] spi: Make GPIO CSs honour the SPI_NO_CS flag Mark Brown
2018-10-16 19:29 ` Trent Piepho
2018-10-17 9:42 ` Mark Brown
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