[PATCH] pinctrl: stm32: fix the unit of the hwspinlock timeout

[PATCH] pinctrl: stm32: fix the unit of the hwspinlock timeout

[Ju Nan]

HWSPNLCK_TIMEOUT is passed to hwspin_lock_timeout_in_atomic(), whose
timeout argument is in milliseconds, not microseconds:

  atomic_delay += HWSPINLOCK_RETRY_DELAY_US;
  if (atomic_delay > to * 1000)
          return -ETIMEDOUT;

So the driver asks for a 1 second timeout where the comment next to the
macro says it wants 1 millisecond.

The hwspinlock core documents this explicitly:

  If the mode is HWLOCK_IN_ATOMIC (called from an atomic context) the
  timeout is handled with busy-waiting delays, hence shall not exceed
  few msecs.

Pass the value the comment always described. The core retries every
HWSPINLOCK_RETRY_DELAY_US (100 us), so the semaphore is still polled ten
times before giving up, which is far longer than any plausible hold time
on the coprocessor side. A timeout is reported with dev_err() and fails
the pin configuration or the interrupt allocation, so shortening it
degrades gracefully.

Signed-off-by: Ju Nan <junan76@163.com>
---
 drivers/pinctrl/stm32/pinctrl-stm32.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pinctrl/stm32/pinctrl-stm32.c b/drivers/pinctrl/stm32/pinctrl-stm32.c
index 6a99708a5..dbc9143ec 100644
--- a/drivers/pinctrl/stm32/pinctrl-stm32.c
+++ b/drivers/pinctrl/stm32/pinctrl-stm32.c
@@ -87,7 +87,7 @@
 #define gpio_range_to_bank(chip) \
 		container_of(chip, struct stm32_gpio_bank, range)
 
-#define HWSPNLCK_TIMEOUT	1000 /* usec */
+#define HWSPNLCK_TIMEOUT	1 /* msec */
 
 static const char * const stm32_gpio_functions[] = {
 	"gpio", "af0", "af1",
-- 
2.55.0