> -----Original Message----- > From: Menon, Nishanth > Sent: Tuesday, April 13, 2010 10:18 PM > To: G, Manjunath Kondaiah > Cc: linux-i2c@xxxxxxxxxxxxxxx; linux-omap@xxxxxxxxxxxxxxx; > ben-linux@xxxxxxxxx; Kalliguddi, Hema > Subject: Re: [PATCH v2] OMAP3: I2C: Errata ID i207: Clear > wrong RDR interrupt > > On 04/13/2010 07:01 AM, G, Manjunath Kondaiah wrote: > > Under certain rare conditions, I2C_STAT[13].RDR bit may be set > > and the corresponding interrupt fire, even there is no data in > > the receive FIFO, or the I2C data transfer is still ongoing. > > These spurious RDR events must be ignored by the software. > > > > This patch handles and ignores RDR spurious interrupts. > > > > Patch tested on OMAP zoom3 board. > > > > Signed-off-by: Manjunatha GK<manjugk@xxxxxx> > > Cc: linux-omap@xxxxxxxxxxxxxxx > > Cc: linux-i2c@xxxxxxxxxxxxxxx > > Cc: ben-linux@xxxxxxxxx > > Cc: Kalliguddi, Hema<hemahk@xxxxxx> > > Cc: Nishanth Menon<nm@xxxxxx> > > --- > > Review comments for earlier post can be found at: > > https://patchwork.kernel.org/patch/90122/ > Overall, the comments have not been implemented, so my NAK continues > unfortunately. please review the comments again. This errata is applicable to OMAP2 and OMAP3 and not applicable to OMAP4. I will update the same in patch description. Rest of review comments will be taken care as explained below. > > > > > drivers/i2c/busses/i2c-omap.c | 32 > +++++++++++++++++++++++++++++++- > > 1 files changed, 31 insertions(+), 1 deletions(-) > > > > diff --git a/drivers/i2c/busses/i2c-omap.c > b/drivers/i2c/busses/i2c-omap.c > > index ae6f5c1..d4ec886 100644 > > --- a/drivers/i2c/busses/i2c-omap.c > > +++ b/drivers/i2c/busses/i2c-omap.c > > @@ -733,10 +733,40 @@ complete: > > } > > if (stat& (OMAP_I2C_STAT_RRDY | OMAP_I2C_STAT_RDR)) { > > u8 num_bytes = 1; > > + > > + /* > > + * I2C Errata(Errata Nos. OMAP2: 1.67, > OMAP3: 1.8) > > + * Not applicable for OMAP4. > > + * Under certain rare conditions, RDR > could be set again > > + * when the bus is busy, then ignore > the interrupt and > > + * clear the interrupt. > > + */ > > + if ((stat& OMAP_I2C_STAT_RDR)&& > !cpu_is_omap44xx()) { > > + /* Step 1: If RDR is set, clear it */ > > + omap_i2c_ack_stat(dev, stat& > OMAP_I2C_STAT_RDR); > > + > > + /* Step 2: */ > > + if(!(omap_i2c_read_reg(dev, > OMAP_I2C_STAT_REG) > > + & > OMAP_I2C_STAT_BB)) { > > + /* Step 3: */ > > + while(omap_i2c_read_reg(dev, > > + OMAP_I2C_STAT_REG) > > + & > OMAP_I2C_STAT_RDR) { > > + > omap_i2c_ack_stat(dev, stat > > + & > OMAP_I2C_STAT_RDR); > > + dev_err(dev->dev, > > + "I2C : RDR when > the bus is busy.\n"); > > + continue; > continue in the inner while loop? NAK. should have been an if > condition > here. It's my bad. I will fix it. > > > + } > > + > > + } > > + else > > + return IRQ_HANDLED; > using a continue is better as commented for patch v1. Agreed. > > > + } > > if (dev->fifo_size) { > > if (stat& OMAP_I2C_STAT_RRDY) > > num_bytes = dev->fifo_size; > > - else /* read RXSTAT on RDR > interrupt */ > > + else /* Step4: read RXSTAT on > RDR interrupt */ > dont really need this.. I have changed only comment. I will revert if it is not required. -Manjunath-- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
