* Manjunatha GK <manjugk@xxxxxx> [100413 06:32]: > 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/ > > 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; > + } > + > + } > + else > + return IRQ_HANDLED; > + } Please move these hacks into a separate inline function that you initialize during the init. Then in the function you do it if OMAP_I2C_QUIRK_1234 flag has been set. In general, it seems that a lot of TI omap4 patches just do: if (!cpu_is_omap4430()) { indent_old_code_even_more ... } else { add_hacks_for_omap4 ... } And sprinkle that all over the place. This is not a maintainable way of doing things. Please do something like this instead: #ifdef CONFIG_ARCH_OMAP4 static inline void omap_i2c_quirk_1234(struct device *dev) { /* Do hacks here */ } #else static inline void omap_i2c_quirk_1234(struct device *dev) { } #endif int omap_i2_some_function(struct device *dev) { ... if (dev->quirks & OMAP_I2C_QUIRK_1234) omap_i2c_quirk_1234(dev); ... } And then in the driver init just set the quirks you need. Regards, Tony -- 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
