From: Alessandro Grassi Date: Fri, 2 May 2025 09:55:20 +0000 (+0200) Subject: spi: spi-sun4i: fix early activation X-Git-Tag: v5.10.238~6 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=9757a1ceeedc4516cb1ed16fcd15c6775d8f7323;p=thirdparty%2Fkernel%2Fstable.git spi: spi-sun4i: fix early activation [ Upstream commit fb98bd0a13de2c9d96cb5c00c81b5ca118ac9d71 ] The SPI interface is activated before the CPOL setting is applied. In that moment, the clock idles high and CS goes low. After a short delay, CPOL and other settings are applied, which may cause the clock to change state and idle low. This transition is not part of a clock cycle, and it can confuse the receiving device. To prevent this unexpected transition, activate the interface while CPOL and the other settings are being applied. Signed-off-by: Alessandro Grassi Link: https://patch.msgid.link/20250502095520.13825-1-alessandro.grassi@mailbox.org Signed-off-by: Mark Brown Signed-off-by: Sasha Levin --- diff --git a/drivers/spi/spi-sun4i.c b/drivers/spi/spi-sun4i.c index 1fdfc6e6691d2..a8fba310d7004 100644 --- a/drivers/spi/spi-sun4i.c +++ b/drivers/spi/spi-sun4i.c @@ -263,6 +263,9 @@ static int sun4i_spi_transfer_one(struct spi_master *master, else reg |= SUN4I_CTL_DHB; + /* Now that the settings are correct, enable the interface */ + reg |= SUN4I_CTL_ENABLE; + sun4i_spi_write(sspi, SUN4I_CTL_REG, reg); /* Ensure that we have a parent clock fast enough */ @@ -403,7 +406,7 @@ static int sun4i_spi_runtime_resume(struct device *dev) } sun4i_spi_write(sspi, SUN4I_CTL_REG, - SUN4I_CTL_ENABLE | SUN4I_CTL_MASTER | SUN4I_CTL_TP); + SUN4I_CTL_MASTER | SUN4I_CTL_TP); return 0;