| Message ID | 21b1db0af4c62a53dc2fcec1e0b1f7b412e6f1be.1474439371.git.jglauber@cavium.com |
|---|---|
| State | Superseded |
| Headers | show |
On Wed, Sep 21, 2016 at 08:51:05AM +0200, Jan Glauber wrote: > Add an additional status check before starting a transaction and, > if required, trigger the recovery if the check fails. > > Signed-off-by: Jan Glauber <jglauber@cavium.com> Won't this break multi-master setups?
On Wed, Sep 21, 2016 at 10:55:41PM +0200, Wolfram Sang wrote: > On Wed, Sep 21, 2016 at 08:51:05AM +0200, Jan Glauber wrote: > > Add an additional status check before starting a transaction and, > > if required, trigger the recovery if the check fails. > > > > Signed-off-by: Jan Glauber <jglauber@cavium.com> > > Won't this break multi-master setups? > I'm afraid yes. I don't have a multi-master setup, but agree that we should not break it. How about re-checking if the bus is idle until a timeout (i2c->adap.timeout ?) happens and only then recover? Additionaly we can check for arbitration loss as Dmitry did in his original patch. --Jan -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/i2c/busses/i2c-octeon-core.c b/drivers/i2c/busses/i2c-octeon-core.c index 5e63b17..b21aa3e 100644 --- a/drivers/i2c/busses/i2c-octeon-core.c +++ b/drivers/i2c/busses/i2c-octeon-core.c @@ -630,6 +630,22 @@ static int octeon_i2c_hlc_comp_write(struct octeon_i2c *i2c, struct i2c_msg *msg return ret; } +static int octeon_i2c_check_bus(struct octeon_i2c *i2c) +{ + int stat, lines; + + stat = octeon_i2c_stat_read(i2c); + + /* get I2C line state */ + lines = octeon_i2c_read_int(i2c) & (TWSI_INT_SCL | TWSI_INT_SDA); + + if (stat == STAT_IDLE && lines == (TWSI_INT_SCL | TWSI_INT_SDA)) + return 0; + + /* bus check failed, try to recover */ + return octeon_i2c_recovery(i2c); +} + /** * octeon_i2c_xfer - The driver's master_xfer function * @adap: Pointer to the i2c_adapter structure @@ -643,6 +659,10 @@ int octeon_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) struct octeon_i2c *i2c = i2c_get_adapdata(adap); int i, ret = 0; + ret = octeon_i2c_check_bus(i2c); + if (ret) + goto out; + if (num == 1) { if (msgs[0].len > 0 && msgs[0].len <= 8) { if (msgs[0].flags & I2C_M_RD)
Add an additional status check before starting a transaction and, if required, trigger the recovery if the check fails. Signed-off-by: Jan Glauber <jglauber@cavium.com> --- drivers/i2c/busses/i2c-octeon-core.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+)