linux-kernel - [PATCH 2/8] spi: Introduce spi-cs-setup-ns property

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20221117105249.115649-3-tudor.ambarus@microchip.com>
Date:   Thu, 17 Nov 2022 12:52:43 +0200
From:   Tudor Ambarus <tudor.ambarus@...rochip.com>
To:     <broonie@...nel.org>, <robh+dt@...nel.org>,
        <krzysztof.kozlowski+dt@...aro.org>, <nicolas.ferre@...rochip.com>,
        <alexandre.belloni@...tlin.com>, <claudiu.beznea@...rochip.com>
CC:     <linux-spi@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-mtd@...ts.infradead.org>,
        Tudor Ambarus <tudor.ambarus@...rochip.com>
Subject: [PATCH 2/8] spi: Introduce spi-cs-setup-ns property

SPI NOR flashes have specific cs-setup time requirements without which
they can't work at frequencies close to their maximum supported frequency,
as they miss the first bits of the instruction command. Unrecognized
commands are ignored, thus the flash will be unresponsive. Introduce the
spi-cs-setup-ns property to allow spi devices to specify their cs setup
time.

Signed-off-by: Tudor Ambarus <tudor.ambarus@...rochip.com>
---
 drivers/spi/spi.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 4ddd250481f5..b93a6085d9a0 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -2224,6 +2224,7 @@ static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
 			   struct device_node *nc)
 {
 	u32 value;
+	u16 cs_setup;
 	int rc;
 
 	/* Mode (clock phase/polarity/etc.) */
@@ -2309,6 +2310,11 @@ static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
 	if (!of_property_read_u32(nc, "spi-max-frequency", &value))
 		spi->max_speed_hz = value;
 
+	if (!of_property_read_u16(nc, "spi-cs-setup-ns", &cs_setup)) {
+		spi->cs_setup.value = cs_setup;
+		spi->cs_setup.unit = SPI_DELAY_UNIT_NSECS;
+	}
+
 	return 0;
 }
 
-- 
2.25.1