diff options
| author | Chris Packham <chris.packham@alliedtelesis.co.nz> | 2021-07-16 08:58:32 +1200 |
|---|---|---|
| committer | Wolfram Sang <wsa@kernel.org> | 2021-07-20 22:32:01 +0200 |
| commit | 4a8ac5e45cdaa88884b4ce05303e304cbabeb367 (patch) | |
| tree | fcf7b8b0a3f46df664ab701e1effca2347b24d18 | |
| parent | a750bff5b99e4097de2fa0cf00b78abb98a3c0d2 (diff) | |
| download | linux-4a8ac5e45cdaa88884b4ce05303e304cbabeb367.tar.bz2 | |
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>
| -rw-r--r-- | drivers/i2c/busses/i2c-mpc.c | 4 |
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; |