* Manjunatha GK <[email protected]> [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 <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: Kalliguddi, Hema <[email protected]>
> Cc: Nishanth Menon <[email protected]>
> ---
> 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
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