| Message ID | ccf553c14d5220f3f9233ac7695d27ee0d55bcc7.1474565039.git.jglauber@cavium.com |
|---|---|
| State | New |
| Headers | show |
On Fri, Sep 23, 2016 at 11:40:38AM +0200, Jan Glauber wrote: > Add an additional status check before starting a transaction. If the > check fails wait for some time to tolerate multi-master mode. After the > timeout expires trigger the recovery. > > Signed-off-by: Jan Glauber <jglauber@cavium.com> Need to think more about it, needs to wait for next cycle.
On Sat, Sep 24, 2016 at 11:24:19AM +0200, Wolfram Sang wrote: > On Fri, Sep 23, 2016 at 11:40:38AM +0200, Jan Glauber wrote: > > Add an additional status check before starting a transaction. If the > > check fails wait for some time to tolerate multi-master mode. After the > > timeout expires trigger the recovery. > > > > Signed-off-by: Jan Glauber <jglauber@cavium.com> > > Need to think more about it, needs to wait for next cycle. > OK, please share your thoughts when you get to it. --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..f526511 100644 --- a/drivers/i2c/busses/i2c-octeon-core.c +++ b/drivers/i2c/busses/i2c-octeon-core.c @@ -630,6 +630,31 @@ 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) +{ + u64 end = get_jiffies_64() + i2c->adap.timeout; + int stat, lines; + + while (time_before64(get_jiffies_64(), end)) { + 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; + + if (stat == STAT_LOST_ARB_38 || stat == STAT_LOST_ARB_68 || + stat == STAT_LOST_ARB_78 || stat == STAT_LOST_ARB_B0) + break; + + usleep_range(I2C_OCTEON_EVENT_WAIT / 2, I2C_OCTEON_EVENT_WAIT); + } + + /* 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 +668,10 @@ 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. If the check fails wait for some time to tolerate multi-master mode. After the timeout expires trigger the recovery. Signed-off-by: Jan Glauber <jglauber@cavium.com> --- drivers/i2c/busses/i2c-octeon-core.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+)