From: Linus Walleij <linus.walleij@linaro.org>
To: Mark Brown <broonie@kernel.org>, linux-spi@vger.kernel.org
Cc: linux-gpio@vger.kernel.org,
Linus Walleij <linus.walleij@linaro.org>,
Andrey Smirnov <andrew.smirnov@gmail.com>
Subject: [PATCH] spi: gpio: Add SPI_MASTER_GPIO_SS flag
Date: Tue, 16 Jul 2019 22:46:51 +0200 [thread overview]
Message-ID: <20190716204651.7743-1-linus.walleij@linaro.org> (raw)
The GPIO SPI master has some code in its local CS
callback to set the initial sck GPIO value. This was
lost in the commit converting it to use SPI core
GPIO handling as this callback isn't called if the
internal GPIO handling is active.
Add the special SPI_MASTER_GPIO_SS to ascertain it
gets called anyway so we get the initial SCK setting
right. There is some platform provided GPIO handling
there as well but this will be skipped as the cs_gpios
will be NULL.
My test targets seem not to care about the initial
SCK value so I am uncertain if this is a regression,
but to preserve the previous semantic we better do
this.
Cc: Andrey Smirnov <andrew.smirnov@gmail.com>
Fixes: 249e2632dcd0 ("spi: gpio: Don't request CS GPIO in DT use-case")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
drivers/spi/spi-gpio.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/spi/spi-gpio.c b/drivers/spi/spi-gpio.c
index eca9d52ecf65..9eb82150666e 100644
--- a/drivers/spi/spi-gpio.c
+++ b/drivers/spi/spi-gpio.c
@@ -410,6 +410,12 @@ static int spi_gpio_probe(struct platform_device *pdev)
bb = &spi_gpio->bitbang;
bb->master = master;
+ /*
+ * There is some additional business, apart from driving the CS GPIO
+ * line, that we need to do on selection. This makes the local
+ * callback for chipselect always get called.
+ */
+ master->flags |= SPI_MASTER_GPIO_SS;
bb->chipselect = spi_gpio_chipselect;
bb->set_line_direction = spi_gpio_set_direction;
--
2.21.0
next reply other threads:[~2019-07-16 20:46 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-16 20:46 Linus Walleij [this message]
2019-07-17 17:58 ` Applied "spi: gpio: Add SPI_MASTER_GPIO_SS flag" to the spi tree Mark Brown
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190716204651.7743-1-linus.walleij@linaro.org \
--to=linus.walleij@linaro.org \
--cc=andrew.smirnov@gmail.com \
--cc=broonie@kernel.org \
--cc=linux-gpio@vger.kernel.org \
--cc=linux-spi@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).