power: reset: ltc2952: Fix use of floating point literals

PATCH Superseded Nathan Chancellor 2 participants 2 messages Nov 4, 2021 System reset/shutdown drivers

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Nathan Chancellor

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2021-11-04 21:51 UTC #0 lore raw

PATCH 1/1 power: reset: ltc2952: Fix use of floating point literals

A new commit in LLVM causes an error on the use of 'long double' when '-mno-x87' is used, which the kernel does through an alias, '-mno-80387' (see the LLVM commit below for more details around why it does this).

drivers/power/reset/ltc2952-poweroff.c:162:28: error: expression requires 'long double' type support, but target 'x86_64-unknown-linux-gnu' does not support it

        data->wde_interval = 300L * 1E6L;
                                  ^
drivers/power/reset/ltc2952-poweroff.c:162:21: error: expression requires  'long double' type support, but target 'x86_64-unknown-linux-gnu' does not support it
        data->wde_interval = 300L * 1E6L;
                           ^
drivers/power/reset/ltc2952-poweroff.c:163:41: error: expression requires  'long double' type support, but target 'x86_64-unknown-linux-gnu' does not support it
        data->trigger_delay = ktime_set(2, 500L*1E6L);
                                               ^

3 errors generated.

This happens due to the use of a 'long double' literal. The 'E6' part of '1E6L' causes the literal to be a 'double' then the 'L' suffix promotes it to 'long double'.

There is no visible reason for floating point values in this driver, as the values are only assigned to integer types. Use USEC_PER_SEC, which is the same integer value as '1E6L', to avoid changing functionality but fix the error.

Fixes 6647156c00cc ("power: reset: add LTC2952 poweroff driver")

Link https://github.com/ClangBuiltLinux/linux/issues/1497

Link https://github.com/llvm/llvm-project/commit/a8083d42b1c346e21623a1d36d1f0cadd7801d83

Signed-off-by Nathan Chancellor <[email protected]>

---
 drivers/power/reset/ltc2952-poweroff.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

drivers/power/reset/ltc2952-poweroff.c +2 -2

index fbb344353fe4..ebe3f2bed4c5 100644
@@ -159,8 +159,8 @@ static void ltc2952_poweroff_kill(void)
 
 static void ltc2952_poweroff_default(struct ltc2952_poweroff *data)
 {
-	data->wde_interval = 300L * 1E6L;
-	data->trigger_delay = ktime_set(2, 500L*1E6L);
+	data->wde_interval = 300L * USEC_PER_SEC;
+	data->trigger_delay = ktime_set(2, 500L * USEC_PER_SEC);
 
 	hrtimer_init(&data->timer_trigger, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 	data->timer_trigger.function = ltc2952_poweroff_timer_trigger;

base-commit: d4439a1189f93d0ac1eaf0197db8e6b3e197d5c7

Signature · 1 line

2.34.0.rc0

Nick Desaulniers

Reviewed-by on v1 1/1

2021-11-04 21:54 UTC #1 lore raw

Quoted 26 lines · Nathan Chancellor

A new commit in LLVM causes an error on the use of 'long double' when '-mno-x87' is used, which the kernel does through an alias, '-mno-80387' (see the LLVM commit below for more details around why it does this).
drivers/power/reset/ltc2952-poweroff.c:162:28: error: expression requires 'long double' type support, but target 'x86_64-unknown-linux-gnu' does not support it
        data->wde_interval = 300L * 1E6L;
                                  ^
drivers/power/reset/ltc2952-poweroff.c:162:21: error: expression requires  'long double' type support, but target 'x86_64-unknown-linux-gnu' does not support it
        data->wde_interval = 300L * 1E6L;
                           ^
drivers/power/reset/ltc2952-poweroff.c:163:41: error: expression requires  'long double' type support, but target 'x86_64-unknown-linux-gnu' does not support it
        data->trigger_delay = ktime_set(2, 500L*1E6L);
                                               ^
3 errors generated.
This happens due to the use of a 'long double' literal. The 'E6' part of '1E6L' causes the literal to be a 'double' then the 'L' suffix promotes it to 'long double'.
There is no visible reason for floating point values in this driver, as the values are only assigned to integer types. Use USEC_PER_SEC, which is the same integer value as '1E6L', to avoid changing functionality but fix the error.

Quoted 4 lines

Fixes 6647156c00cc ("power: reset: add LTC2952 poweroff driver")
Link https://github.com/ClangBuiltLinux/linux/issues/1497
Link https://github.com/llvm/llvm-project/commit/a8083d42b1c346e21623a1d36d1f0cadd7801d83
Signed-off-by Nathan Chancellor <[email protected]>

Thanks for the patch!

Reviewed-by Nick Desaulniers <[email protected]>

Quoted 24 lines

---
 drivers/power/reset/ltc2952-poweroff.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

drivers/power/reset/ltc2952-poweroff.c +2 -2

index fbb344353fe4..ebe3f2bed4c5 100644
@@ -159,8 +159,8 @@ static void ltc2952_poweroff_kill(void)
 
 static void ltc2952_poweroff_default(struct ltc2952_poweroff *data)
 {
-       data->wde_interval = 300L * 1E6L;
-       data->trigger_delay = ktime_set(2, 500L*1E6L);
+       data->wde_interval = 300L * USEC_PER_SEC;
+       data->trigger_delay = ktime_set(2, 500L * USEC_PER_SEC);
 
        hrtimer_init(&data->timer_trigger, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
        data->timer_trigger.function = ltc2952_poweroff_timer_trigger;

base-commit: d4439a1189f93d0ac1eaf0197db8e6b3e197d5c7 --
2.34.0.rc0

Signature · 2 lines

Thanks,
~Nick Desaulniers