6.9-stable review patch. If anyone has any objections, please let me know.
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From: Sai Pavan Boddu sai.pavan.boddu@amd.com
[ Upstream commit c2e55b449de7298a751ed0256251019d302af453 ]
The Driver unintentionally programs ctrl reg to clear the fifo, which happens after the start of transaction. Previously, this was not an issue as it involved read-modified-write. However, this issue breaks i2c reads on QEMU, as i2c-read is executed before guest starts programming control register.
Fixes: ff0cf7bca630 ("i2c: cadence: Remove unnecessary register reads") Signed-off-by: Sai Pavan Boddu sai.pavan.boddu@amd.com Acked-by: Michal Simek michal.simek@amd.com Signed-off-by: Andi Shyti andi.shyti@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/i2c/busses/i2c-cadence.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/i2c/busses/i2c-cadence.c b/drivers/i2c/busses/i2c-cadence.c index 4bb7d6756947c..2fce3e84ba646 100644 --- a/drivers/i2c/busses/i2c-cadence.c +++ b/drivers/i2c/busses/i2c-cadence.c @@ -633,6 +633,7 @@ static void cdns_i2c_mrecv(struct cdns_i2c *id)
if (hold_clear) { ctrl_reg &= ~CDNS_I2C_CR_HOLD; + ctrl_reg &= ~CDNS_I2C_CR_CLR_FIFO; /* * In case of Xilinx Zynq SOC, clear the HOLD bit before transfer size * register reaches '0'. This is an IP bug which causes transfer size