From: Alessandro Grassi Date: Fri, 2 May 2025 09:55:20 +0000 (+0200) Subject: spi: spi-sun4i: fix early activation X-Git-Tag: v6.15-rc7~18^2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=fb98bd0a13de2c9d96cb5c00c81b5ca118ac9d71;p=thirdparty%2Flinux.git spi: spi-sun4i: fix early activation 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 --- diff --git a/drivers/spi/spi-sun4i.c b/drivers/spi/spi-sun4i.c index f89826d7dc496..aa92fd5a35a98 100644 --- a/drivers/spi/spi-sun4i.c +++ b/drivers/spi/spi-sun4i.c @@ -264,6 +264,9 @@ static int sun4i_spi_transfer_one(struct spi_controller *host, 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 */ @@ -404,7 +407,7 @@ 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;