From: David Lechner <david@lechnology.com>
To: linux-spi@vger.kernel.org, linux-iio@vger.kernel.org
Cc: David Lechner <david@lechnology.com>,
Jonathan Cameron <jic23@kernel.org>,
Hartmut Knaack <knaack.h@gmx.de>,
Lars-Peter Clausen <lars@metafoo.de>,
Peter Meerwald-Stadler <pmeerw@pmeerw.net>,
Mark Brown <broonie@kernel.org>,
Geert Uytterhoeven <geert@linux-m68k.org>,
linux-kernel@vger.kernel.org
Subject: [PATCH 1/3] spi: always use software fallback for SPI_CS_WORD when using cs_gio
Date: Tue, 18 Sep 2018 12:08:48 -0500 [thread overview]
Message-ID: <20180918170850.2749-2-david@lechnology.com> (raw)
In-Reply-To: <20180918170850.2749-1-david@lechnology.com>
This modifies the condition for using the software fallback
implementation for SPI_CS_WORD when the SPI controller is using a GPIO
for the CS line. When using a GPIO for CS, the hardware implementation
won't work, so we just enable the software fallback globally in this
case.
Signed-off-by: David Lechner <david@lechnology.com>
---
drivers/spi/spi.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index e4fb87b304a0..03833924ca6c 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -2841,11 +2841,13 @@ static int __spi_validate(struct spi_device *spi, struct spi_message *message)
return -EINVAL;
/* If an SPI controller does not support toggling the CS line on each
- * transfer (indicated by the SPI_CS_WORD flag), we can emulate it by
+ * transfer (indicated by the SPI_CS_WORD flag) or we are using a GPIO
+ * for the CS line, we can emulate the CS-per-word hardware function by
* splitting transfers into one-word transfers and ensuring that
* cs_change is set for each transfer.
*/
- if ((spi->mode & SPI_CS_WORD) && !(ctlr->mode_bits & SPI_CS_WORD)) {
+ if ((spi->mode & SPI_CS_WORD) && (!(ctlr->mode_bits & SPI_CS_WORD) ||
+ gpio_is_valid(spi->cs_gpio))) {
size_t maxsize;
int ret;
--
2.17.1
next prev parent reply other threads:[~2018-09-18 17:09 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-18 17:08 [PATCH 0/3] spi: SPI_CS_WORD followup David Lechner
2018-09-18 17:08 ` David Lechner [this message]
2018-09-18 17:45 ` Applied "spi: always use software fallback for SPI_CS_WORD when using cs_gio" to the spi tree Mark Brown
2018-09-18 17:08 ` [PATCH 2/3] spi: spi-davinci: Don't error when SPI_CS_WORD and cs_gpio David Lechner
2018-09-18 17:45 ` Applied "spi: spi-davinci: Don't error when SPI_CS_WORD and cs_gpio" to the spi tree Mark Brown
2018-09-18 17:08 ` [PATCH 3/3] iio: adc: ti-ads7950: use SPI_CS_WORD to reduce CPU usage David Lechner
2018-09-18 17:14 ` David Lechner
2018-09-22 9:12 ` Jonathan Cameron
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