The FIFO flush function uses a jiffies amount to detect timeouts as the
flushing is async. Replace with ktime to get more accurate precision
and support short timeouts.
Signed-off-by: Théo Lebrun <[email protected]>
---
drivers/i2c/busses/i2c-nomadik.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/i2c/busses/i2c-nomadik.c b/drivers/i2c/busses/i2c-nomadik.c
index e68b8e0d7919..afd54999bbbb 100644
--- a/drivers/i2c/busses/i2c-nomadik.c
+++ b/drivers/i2c/busses/i2c-nomadik.c
@@ -219,8 +219,8 @@ static inline void i2c_clr_bit(void __iomem *reg, u32 mask)
static int flush_i2c_fifo(struct nmk_i2c_dev *priv)
{
#define LOOP_ATTEMPTS 10
+ ktime_t timeout;
int i;
- unsigned long timeout;
/*
* flush the transmit and receive FIFO. The flushing
@@ -232,9 +232,9 @@ static int flush_i2c_fifo(struct nmk_i2c_dev *priv)
writel((I2C_CR_FTX | I2C_CR_FRX), priv->virtbase + I2C_CR);
for (i = 0; i < LOOP_ATTEMPTS; i++) {
- timeout = jiffies + priv->adap.timeout;
+ timeout = ktime_add_us(ktime_get(), priv->timeout_usecs);
- while (!time_after(jiffies, timeout)) {
+ while (ktime_after(timeout, ktime_get())) {
if ((readl(priv->virtbase + I2C_CR) &
(I2C_CR_FTX | I2C_CR_FRX)) == 0)
return 0;
--
2.43.1
On Thu, Feb 15, 2024 at 5:52 PM Théo Lebrun <[email protected]> wrote:
> The FIFO flush function uses a jiffies amount to detect timeouts as the
> flushing is async. Replace with ktime to get more accurate precision
> and support short timeouts.
>
> Signed-off-by: Théo Lebrun <[email protected]>
Excellent patch. Thanks.
Reviewed-by: Linus Walleij <[email protected]>
Yours,
Linus Walleij
Hello,
On Mon Feb 19, 2024 at 3:21 PM CET, Linus Walleij wrote:
> On Thu, Feb 15, 2024 at 5:52 PM Théo Lebrun <[email protected]> wrote:
>
> > The FIFO flush function uses a jiffies amount to detect timeouts as the
> > flushing is async. Replace with ktime to get more accurate precision
> > and support short timeouts.
> >
> > Signed-off-by: Théo Lebrun <[email protected]>
>
> Excellent patch. Thanks.
> Reviewed-by: Linus Walleij <[email protected]>
Somewhat related to this patch: while writing it, I noticed the total
timeout of flush_i2c_fifo() is 10 times the timeout. Without this
series, this means 10*200ms of busywaiting!
If you have an opinion on a more sensible option for this I could add a
patch to my V2. I don't know enough to pick a sensible value.
I'm unsure if it makes sense that the timeout of flush_i2c_fifo() is a
multiple of the transfer timeout. Does it make sense that those two
timeouts are correlated?
Big thanks for your review,
--
Théo Lebrun, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
On Mon, Feb 19, 2024 at 3:38 PM Théo Lebrun <[email protected]> wrote:
> Somewhat related to this patch: while writing it, I noticed the total
> timeout of flush_i2c_fifo() is 10 times the timeout. Without this
> series, this means 10*200ms of busywaiting!
>
> If you have an opinion on a more sensible option for this I could add a
> patch to my V2. I don't know enough to pick a sensible value.
>
> I'm unsure if it makes sense that the timeout of flush_i2c_fifo() is a
> multiple of the transfer timeout. Does it make sense that those two
> timeouts are correlated?
I have a *vague* memory of the timeouts for flushing needing to be longer
but I might be mistaken. This is probably a Srinidhi or even Sachin question...
Sadly I don't have their current mail addresses.
Yours,
Linus Walleij