kernel: backport v5.8 i2c-pxa updates

[openwrt/staging/dedeckeh.git] / target / linux / generic / backport-5.4 / 819-v5.8-i2c-pxa-clear-all-master-action-bits-in-i2c_pxa_stop.patch

diff --git a/target/linux/generic/backport-5.4/819-v5.8-i2c-pxa-clear-all-master-action-bits-in-i2c_pxa_stop.patch b/target/linux/generic/backport-5.4/819-v5.8-i2c-pxa-clear-all-master-action-bits-in-i2c_pxa_stop.patch
new file mode 100644 (file)
index 0000000..9976707
--- /dev/null
+++ b/target/linux/generic/backport-5.4/819-v5.8-i2c-pxa-clear-all-master-action-bits-in-i2c_pxa_stop.patch
@@ -0,0 +1,43 @@
+From: Russell King <rmk+kernel@armlinux.org.uk>
+Bcc: linux@mail.armlinux.org.uk
+Subject: [PATCH 5/7] i2c: pxa: clear all master action bits in
+ i2c_pxa_stop_message()
+MIME-Version: 1.0
+Content-Disposition: inline
+Content-Transfer-Encoding: 8bit
+Content-Type: text/plain; charset="utf-8"
+
+If we timeout during a message transfer, the control register may
+contain bits that cause an action to be set. Read-modify-writing the
+register leaving these bits set may trigger the hardware to attempt
+one of these actions unintentionally.
+
+Always clear these bits when cleaning up after a message or after
+a timeout.
+
+Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
+---
+ drivers/i2c/busses/i2c-pxa.c | 6 ++----
+ 1 file changed, 2 insertions(+), 4 deletions(-)
+
+diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
+index db739cce93ac..a72d07bdb793 100644
+--- a/drivers/i2c/busses/i2c-pxa.c
++++ b/drivers/i2c/busses/i2c-pxa.c
+@@ -795,11 +795,9 @@ static inline void i2c_pxa_stop_message(struct pxa_i2c *i2c)
+ {
+       u32 icr;
+ 
+-      /*
+-       * Clear the STOP and ACK flags
+-       */
++      /* Clear the START, STOP, ACK, TB and MA flags */
+       icr = readl(_ICR(i2c));
+-      icr &= ~(ICR_STOP | ICR_ACKNAK);
++      icr &= ~(ICR_START | ICR_STOP | ICR_ACKNAK | ICR_TB | ICR_MA);
+       writel(icr, _ICR(i2c));
+ }
+ 
+-- 
+2.20.1
+