2018-12-16 22:14:11

by Amir Mahdi Ghorbanian

[permalink] [raw]
Subject: [PATCH] Staging: nvec: nvec: fixed check style issues

Replaced udelay() by the preferred usleep_range() function.

Signed-off-by: Amir Mahdi Ghorbanian <[email protected]>
---
drivers/staging/nvec/nvec.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/nvec/nvec.c b/drivers/staging/nvec/nvec.c
index 08027a3..6f35f92 100644
--- a/drivers/staging/nvec/nvec.c
+++ b/drivers/staging/nvec/nvec.c
@@ -626,7 +626,7 @@ static irqreturn_t nvec_interrupt(int irq, void *dev)
break;
case 2: /* first byte after command */
if (status == (I2C_SL_IRQ | RNW | RCVD)) {
- udelay(33);
+ usleep_range(0, 33);
if (nvec->rx->data[0] != 0x01) {
dev_err(nvec->dev,
"Read without prior read command\n");
@@ -713,7 +713,7 @@ static irqreturn_t nvec_interrupt(int irq, void *dev)
* We experience less incomplete messages with this delay than without
* it, but we don't know why. Help is appreciated.
*/
- udelay(100);
+ usleep_range(0, 100);

return IRQ_HANDLED;
}
--
2.7.4



2018-12-16 22:31:52

by Joe Perches

[permalink] [raw]
Subject: Re: [PATCH] Staging: nvec: nvec: fixed check style issues

On Sun, 2018-12-16 at 13:43 -0800, Amir Mahdi Ghorbanian wrote:
> Replaced udelay() by the preferred usleep_range() function.
[]
> diff --git a/drivers/staging/nvec/nvec.c b/drivers/staging/nvec/nvec.c
[]
> @@ -626,7 +626,7 @@ static irqreturn_t nvec_interrupt(int irq, void *dev)
> break;
> case 2: /* first byte after command */
> if (status == (I2C_SL_IRQ | RNW | RCVD)) {
> - udelay(33);
> + usleep_range(0, 33);

Umm, this is not the same outcome.

udelay delays a minimum of 33 usecs.
usleep_range delays from min to max usecs.


kernel/time/timer.c: * usleep_range - Sleep for an approximate time
kernel/time/timer.c- * @min: Minimum time in usecs to sleep
kernel/time/timer.c- * @max: Maximum time in usecs to sleep
kernel/time/timer.c- *
kernel/time/timer.c- * In non-atomic context where the exact wakeup time is flexible, use
kernel/time/timer.c: * usleep_range() instead of udelay(). The sleep improves responsiveness
kernel/time/timer.c- * by avoiding the CPU-hogging busy-wait of udelay(), and the range reduces
kernel/time/timer.c- * power usage by allowing hrtimers to take advantage of an already-
kernel/time/timer.c- * scheduled interrupt instead of scheduling a new one just for this sleep.
kernel/time/timer.c- */

> if (nvec->rx->data[0] != 0x01) {
> dev_err(nvec->dev,
> "Read without prior read command\n");
> @@ -713,7 +713,7 @@ static irqreturn_t nvec_interrupt(int irq, void *dev)
> * We experience less incomplete messages with this delay than without
> * it, but we don't know why. Help is appreciated.
> */
> - udelay(100);
> + usleep_range(0, 100);

here too.



2018-12-16 23:05:29

by Joey Pabalinas

[permalink] [raw]
Subject: Re: [PATCH] Staging: nvec: nvec: fixed check style issues

On Sun, Dec 16, 2018 at 01:43:54PM -0800, Amir Mahdi Ghorbanian wrote:
> Replaced udelay() by the preferred usleep_range() function.
>
> Signed-off-by: Amir Mahdi Ghorbanian <[email protected]>

Nack, usleep_range isn't for atomic contexts like interrupt handlers.

> ---
> drivers/staging/nvec/nvec.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/staging/nvec/nvec.c b/drivers/staging/nvec/nvec.c
> index 08027a3..6f35f92 100644
> --- a/drivers/staging/nvec/nvec.c
> +++ b/drivers/staging/nvec/nvec.c
> @@ -626,7 +626,7 @@ static irqreturn_t nvec_interrupt(int irq, void *dev)
> break;
> case 2: /* first byte after command */
> if (status == (I2C_SL_IRQ | RNW | RCVD)) {
> - udelay(33);
> + usleep_range(0, 33);
> if (nvec->rx->data[0] != 0x01) {
> dev_err(nvec->dev,
> "Read without prior read command\n");
> @@ -713,7 +713,7 @@ static irqreturn_t nvec_interrupt(int irq, void *dev)
> * We experience less incomplete messages with this delay than without
> * it, but we don't know why. Help is appreciated.
> */
> - udelay(100);
> + usleep_range(0, 100);
>
> return IRQ_HANDLED;
> }
> --
> 2.7.4
>

--
Cheers,
Joey Pabalinas


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