diff options
Diffstat (limited to 'target/linux/bcm27xx/patches-5.4/950-0665-spi-use_gpio_descriptor-fixup-moved-to-spi_setup.patch')
| -rw-r--r-- | target/linux/bcm27xx/patches-5.4/950-0665-spi-use_gpio_descriptor-fixup-moved-to-spi_setup.patch | 55 |
1 files changed, 0 insertions, 55 deletions
diff --git a/target/linux/bcm27xx/patches-5.4/950-0665-spi-use_gpio_descriptor-fixup-moved-to-spi_setup.patch b/target/linux/bcm27xx/patches-5.4/950-0665-spi-use_gpio_descriptor-fixup-moved-to-spi_setup.patch deleted file mode 100644 index 402635d838..0000000000 --- a/target/linux/bcm27xx/patches-5.4/950-0665-spi-use_gpio_descriptor-fixup-moved-to-spi_setup.patch +++ /dev/null @@ -1,55 +0,0 @@ -From b4659f44df3454c6b37ba206a0347af3b8d6a744 Mon Sep 17 00:00:00 2001 -From: Phil Elwell <phil@raspberrypi.com> -Date: Mon, 20 Apr 2020 13:30:49 +0100 -Subject: [PATCH] spi: use_gpio_descriptor fixup moved to spi_setup - -Commits [1] and [2] including code that forces SPI_CS_HIGH for SPI -controllers that use GPIO descriptors, the SPI_CS_HIGH flag being -there to avoid a double-negation (since SPI CS is usually active-low). -The motivation for pushing the knowledge of the required polarity into -the GPIO descriptor allows the switch to an output to request the -correct inactive level, avoiding a needless glitch. - -The problem with setting the flag early as [1] does is that it appears -in the mode field that is passed to client drivers during their probing, -when they may want to choose SPI_POL, SPI_PHA and (just possibly) -SPI_CS_HIGH. Since SPI_CS_HIGH is the exception, most drivers won't -set it and the anti-negation negation is lost. [2] acknowledges that -problem and patches things up for the case of users of spidev, but -omits regular kernel-mode drivers. - -Downstream commit [3] moves the forcing of SPI_CS_HIGH to spi_setup, -after the driver probing. Since this code is called before any CS -manipulation it is early enough to be effective, but late enough that -clients have already had their chance to change the mode field. - -This is a partial reversion of [1], and is accompanied by a complete -reversion of [2], neither of which is needed any longer. - -[1] f3186dd87669 ("spi: Optionally use GPIO descriptors for CS GPIOs") -[2] 83b2a8fe43bd ("spi: spidev: Fix CS polarity if GPIO descriptors are used") -[3] <varies> ("spi: Force CS_HIGH if GPIO descriptors are used") - -Signed-off-by: Phil Elwell <phil@raspberrypi.com> ---- - drivers/spi/spi.c | 9 --------- - 1 file changed, 9 deletions(-) - ---- a/drivers/spi/spi.c -+++ b/drivers/spi/spi.c -@@ -1799,15 +1799,6 @@ static int of_spi_parse_dt(struct spi_co - } - 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 && -- 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) { |