linux-kernel - [PATCH 6.8 641/715] spi: Restore delays for non-GPIO chip select

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Date: Sun, 24 Mar 2024 18:33:40 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Cc: Janne Grunau <j@...nau.net>,
	Mark Brown <broonie@...nel.org>,
	Sasha Levin <sashal@...nel.org>
Subject: [PATCH 6.8 641/715] spi: Restore delays for non-GPIO chip select

From: Janne Grunau <j@...nau.net>

[ Upstream commit aa0162dc0dd95c3bf248e3c78068760094e8f64b ]

SPI controller with integrated chip select handling still need to adhere
to SPI device's CS setup, hold and inactive delays. For controller
without set_cs_timing spi core shall handle the delays to avoid
duplicated delay handling in each controller driver.
Fixes a regression for the out of tree SPI controller and SPI HID
transport on Apple M1/M1 Pro/Max notebooks.

Fixes: 4d8ff6b0991d ("spi: Add multi-cs memories support in SPI core")
Signed-off-by: Janne Grunau <j@...nau.net>
Link: https://msgid.link/r/20240311-spi-cs-delays-regression-v1-1-0075020a90b2@jannau.net
Signed-off-by: Mark Brown <broonie@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/spi/spi.c | 24 ++++++++++++++----------
 1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index d1b297f438f14..46f1535487608 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1042,10 +1042,14 @@ static void spi_set_cs(struct spi_device *spi, bool enable, bool force)
 	if (spi->mode & SPI_CS_HIGH)
 		enable = !enable;
 
-	if (spi_is_csgpiod(spi)) {
-		if (!spi->controller->set_cs_timing && !activate)
-			spi_delay_exec(&spi->cs_hold, NULL);
+	/*
+	 * Handle chip select delays for GPIO based CS or controllers without
+	 * programmable chip select timing.
+	 */
+	if ((spi_is_csgpiod(spi) || !spi->controller->set_cs_timing) && !activate)
+		spi_delay_exec(&spi->cs_hold, NULL);
 
+	if (spi_is_csgpiod(spi)) {
 		if (!(spi->mode & SPI_NO_CS)) {
 			/*
 			 * Historically ACPI has no means of the GPIO polarity and
@@ -1079,16 +1083,16 @@ static void spi_set_cs(struct spi_device *spi, bool enable, bool force)
 		if ((spi->controller->flags & SPI_CONTROLLER_GPIO_SS) &&
 		    spi->controller->set_cs)
 			spi->controller->set_cs(spi, !enable);
-
-		if (!spi->controller->set_cs_timing) {
-			if (activate)
-				spi_delay_exec(&spi->cs_setup, NULL);
-			else
-				spi_delay_exec(&spi->cs_inactive, NULL);
-		}
 	} else if (spi->controller->set_cs) {
 		spi->controller->set_cs(spi, !enable);
 	}
+
+	if (spi_is_csgpiod(spi) || !spi->controller->set_cs_timing) {
+		if (activate)
+			spi_delay_exec(&spi->cs_setup, NULL);
+		else
+			spi_delay_exec(&spi->cs_inactive, NULL);
+	}
 }
 
 #ifdef CONFIG_HAS_DMA
-- 
2.43.0