linux-kernel - [PATCH] spi: Fix SPI_CS_HIGH setting when using native and GPIO CS

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Date:   Fri, 18 Oct 2019 17:29:29 +0200
From:   Gregory CLEMENT <gregory.clement@...tlin.com>
To:     Mark Brown <broonie@...nel.org>, linux-spi@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     Nicolas Ferre <nicolas.ferre@...rochip.com>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Ludovic Desroches <ludovic.desroches@...rochip.com>,
        linux-arm-kernel@...ts.infradead.org,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
        Gregory CLEMENT <gregory.clement@...tlin.com>,
        stable@...r.kernel.org
Subject: [PATCH] spi: Fix SPI_CS_HIGH setting when using native and GPIO CS

When improving the CS GPIO support at core level, the SPI_CS_HIGH
has been enabled for all the CS lines used for a given SPI controller.

However, the SPI framework allows to have on the same controller native
CS and GPIO CS. The native CS may not support the SPI_CS_HIGH, so they
should not be setup automatically.

With this patch the setting is done only for the CS that will use a
GPIO as CS

Fixes: f3186dd87669 ("spi: Optionally use GPIO descriptors for CS GPIOs")
Cc: <stable@...r.kernel.org>
Signed-off-by: Gregory CLEMENT <gregory.clement@...tlin.com>
---
 drivers/spi/spi.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 5414a10afd65..1b68acc28c8f 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1880,15 +1880,7 @@ static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
 		spi->mode |= SPI_3WIRE;
 	if (of_property_read_bool(nc, "spi-lsb-first"))
 		spi->mode |= SPI_LSB_FIRST;
-
-	/*
-	 * For descriptors associated with the device, polarity inversion is
-	 * handled in the gpiolib, so all chip selects are "active high" in
-	 * the logical sense, the gpiolib will invert the line if need be.
-	 */
-	if (ctlr->use_gpio_descriptors)
-		spi->mode |= SPI_CS_HIGH;
-	else if (of_property_read_bool(nc, "spi-cs-high"))
+	if (of_property_read_bool(nc, "spi-cs-high"))
 		spi->mode |= SPI_CS_HIGH;
 
 	/* Device DUAL/QUAD mode */
@@ -1952,6 +1944,14 @@ static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
 	}
 	spi->chip_select = value;
 
+	/*
+	 * For descriptors associated with the device, polarity inversion is
+	 * handled in the gpiolib, so all gpio chip selects are "active high"
+	 * in the logical sense, the gpiolib will invert the line if need be.
+	 */
+	if ((ctlr->use_gpio_descriptors) && ctlr->cs_gpiods[spi->chip_select])
+		spi->mode |= SPI_CS_HIGH;
+
 	/* Device speed */
 	rc = of_property_read_u32(nc, "spi-max-frequency", &value);
 	if (rc) {
-- 
2.23.0