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openmptcprouter/6.12/target/linux/bcm27xx/patches-6.12/950-0413-spi-bcm2835-Support-spi0-0cs-and-SPI_NO_CS-mode.patch
Ycarus (Yannick Chabanois) bdb9b0046f Add bcm27xx 6.12 test support
2024-12-20 14:17:26 +01:00

42 lines
1.5 KiB
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From 69e6058ae026e6d73796b698e5a95e32d9b5a742 Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.com>
Date: Mon, 8 Jan 2024 11:42:57 +0000
Subject: [PATCH 413/697] spi: bcm2835: Support spi0-0cs and SPI_NO_CS mode
The forced conversion of native CS lines into software CS lines is done
whether or not the controller has been given any CS lines to use. This
breaks the use of the spi0-0cs overlay to prevent SPI from claiming any
CS lines, particularly with spidev which doesn't pass in the SPI_NO_CS
flag at creation.
Use the presence of an empty cs-gpios property as an indication that no
CS lines should be used, bypassing the native CS conversion code.
See: https://github.com/raspberrypi/linux/issues/5835
Signed-off-by: Phil Elwell <phil@raspberrypi.com>
---
drivers/spi/spi-bcm2835.c | 5 +++++
1 file changed, 5 insertions(+)
--- a/drivers/spi/spi-bcm2835.c
+++ b/drivers/spi/spi-bcm2835.c
@@ -1225,6 +1225,7 @@ static int bcm2835_spi_setup(struct spi_
struct bcm2835_spi *bs = spi_controller_get_devdata(ctlr);
struct bcm2835_spidev *target = spi_get_ctldata(spi);
struct gpiod_lookup_table *lookup __free(kfree) = NULL;
+ int len;
int ret;
u32 cs;
@@ -1290,6 +1291,10 @@ static int bcm2835_spi_setup(struct spi_
goto err_cleanup;
}
+ /* Skip forced CS conversion if controller has an empty cs-gpios property */
+ if (of_find_property(ctlr->dev.of_node, "cs-gpios", &len) && len == 0)
+ return 0;
+
/*
* TODO: The code below is a slightly better alternative to the utter
* abuse of the GPIO API that I found here before. It creates a