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authorChris Packham <chris.packham@alliedtelesis.co.nz>2021-07-15 23:58:32 +0300
committerWolfram Sang <wsa@kernel.org>2021-07-20 23:32:01 +0300
commit4a8ac5e45cdaa88884b4ce05303e304cbabeb367 (patch)
treefcf7b8b0a3f46df664ab701e1effca2347b24d18 /drivers/i2c/busses/i2c-mpc.c
parenta750bff5b99e4097de2fa0cf00b78abb98a3c0d2 (diff)
downloadlinux-4a8ac5e45cdaa88884b4ce05303e304cbabeb367.tar.xz
i2c: mpc: Poll for MCF
During some transfers the bus can still be busy when an interrupt is received. Commit 763778cd7926 ("i2c: mpc: Restore reread of I2C status register") attempted to address this by re-reading MPC_I2C_SR once but that just made it less likely to happen without actually preventing it. Instead of a single re-read, poll with a timeout so that the bus is given enough time to settle but a genuine stuck SCL is still noticed. Fixes: 1538d82f4647 ("i2c: mpc: Interrupt driven transfer") Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Signed-off-by: Wolfram Sang <wsa@kernel.org>
Diffstat (limited to 'drivers/i2c/busses/i2c-mpc.c')
-rw-r--r--drivers/i2c/busses/i2c-mpc.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/i2c/busses/i2c-mpc.c b/drivers/i2c/busses/i2c-mpc.c
index 6d5014ebaab5..a6ea1eb1394e 100644
--- a/drivers/i2c/busses/i2c-mpc.c
+++ b/drivers/i2c/busses/i2c-mpc.c
@@ -635,8 +635,8 @@ static irqreturn_t mpc_i2c_isr(int irq, void *dev_id)
status = readb(i2c->base + MPC_I2C_SR);
if (status & CSR_MIF) {
- /* Read again to allow register to stabilise */
- status = readb(i2c->base + MPC_I2C_SR);
+ /* Wait up to 100us for transfer to properly complete */
+ readb_poll_timeout(i2c->base + MPC_I2C_SR, status, !(status & CSR_MCF), 0, 100);
writeb(0, i2c->base + MPC_I2C_SR);
mpc_i2c_do_intr(i2c, status);
return IRQ_HANDLED;