| Message ID | 1333345982-16595-1-git-send-email-alokc@nvidia.com |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
On 04/01/2012 11:53 PM, Alok Chauhan wrote: > NACK interrupt generated before I2C controller generates > the STOP condition on bus. In Software, because of this > reset of controller is happening before I2C controller could > complete STOP condition. So wait for some time before resetting > the controller so that STOP condition has delivered properly on bus. > > Added delay of 2 clock period before reset the > controller in case of NACK error. > > Signed-off-by: Alok Chauhan <alokc@nvidia.com> Acked-by: Stephen Warren <swarren@wwwdotorg.org> -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 04/02/2012 01:58 PM, Stephen Warren wrote: > On 04/01/2012 11:53 PM, Alok Chauhan wrote: >> NACK interrupt generated before I2C controller generates >> the STOP condition on bus. In Software, because of this >> reset of controller is happening before I2C controller could >> complete STOP condition. So wait for some time before resetting >> the controller so that STOP condition has delivered properly on bus. >> >> Added delay of 2 clock period before reset the >> controller in case of NACK error. >> >> Signed-off-by: Alok Chauhan <alokc@nvidia.com> > > Acked-by: Stephen Warren <swarren@wwwdotorg.org> Wolfram, Ben, can this be picked up for 3.5? -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Apr 02, 2012 at 11:23:02AM +0530, Alok Chauhan wrote: > NACK interrupt generated before I2C controller generates > the STOP condition on bus. In Software, because of this > reset of controller is happening before I2C controller could > complete STOP condition. So wait for some time before resetting > the controller so that STOP condition has delivered properly on bus. > > Added delay of 2 clock period before reset the > controller in case of NACK error. > > Signed-off-by: Alok Chauhan <alokc@nvidia.com> Applied with Stephen's ACK and slightly reworded comment and commit msg. Wondering a bit that you want it for 3.5, not for 3.4. Looks like a bugfix to me.
On 04/18/2012 08:27 AM, Wolfram Sang wrote: > On Mon, Apr 02, 2012 at 11:23:02AM +0530, Alok Chauhan wrote: >> NACK interrupt generated before I2C controller generates >> the STOP condition on bus. In Software, because of this >> reset of controller is happening before I2C controller could >> complete STOP condition. So wait for some time before resetting >> the controller so that STOP condition has delivered properly on bus. >> >> Added delay of 2 clock period before reset the >> controller in case of NACK error. >> >> Signed-off-by: Alok Chauhan <alokc@nvidia.com> > > Applied with Stephen's ACK and slightly reworded comment and commit msg. > > Wondering a bit that you want it for 3.5, not for 3.4. Looks like a > bugfix to me. Yes, applying this to 3.4 would make sense. When I said "for 3.5" earlier, I meant I'd like it to at least get into 3.5 not later. Thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
> > Applied with Stephen's ACK and slightly reworded comment and commit msg. > > > > Wondering a bit that you want it for 3.5, not for 3.4. Looks like a > > bugfix to me. > > Yes, applying this to 3.4 would make sense. When I said "for 3.5" > earlier, I meant I'd like it to at least get into 3.5 not later. Done, thanks for clarifying.
diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c index e978635..dfb850a8 100644 --- a/drivers/i2c/busses/i2c-tegra.c +++ b/drivers/i2c/busses/i2c-tegra.c @@ -516,6 +516,14 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev, if (likely(i2c_dev->msg_err == I2C_ERR_NONE)) return 0; + /* + * NACK interrupt generated before I2C controller generates the STOP + * condition on bus. So wait for some time before reset the controller + * so that STOP condition has delivered properly on bus. + */ + if (i2c_dev->msg_err == I2C_ERR_NO_ACK) + udelay(DIV_ROUND_UP(2 * 1000000, i2c_dev->bus_clk_rate)); + tegra_i2c_init(i2c_dev); if (i2c_dev->msg_err == I2C_ERR_NO_ACK) { if (msg->flags & I2C_M_IGNORE_NAK)
NACK interrupt generated before I2C controller generates the STOP condition on bus. In Software, because of this reset of controller is happening before I2C controller could complete STOP condition. So wait for some time before resetting the controller so that STOP condition has delivered properly on bus. Added delay of 2 clock period before reset the controller in case of NACK error. Signed-off-by: Alok Chauhan <alokc@nvidia.com> --- Added the more descriptive commit message about issue in case of NACK error condition. Changed the comment in code also drivers/i2c/busses/i2c-tegra.c | 8 ++++++++ 1 files changed, 8 insertions(+), 0 deletions(-)