Now that we have a standard ACPI helper, we can use acpi_dev_uid_match()
for matching _UID as per the original logic before commit 2a036e489eb1
("ACPI: LPSS: Refactor _UID handling to use acpi_dev_uid_to_integer()"),
instead of treating it as an integer.

Signed-off-by: Raag Jadav <raag.jadav@intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
Changes since v1:
- Update commit message

 drivers/acpi/acpi_lpss.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/drivers/acpi/acpi_lpss.c b/drivers/acpi/acpi_lpss.c
index 875de44961bf..6aaa6b066510 100644
--- a/drivers/acpi/acpi_lpss.c
+++ b/drivers/acpi/acpi_lpss.c
@@ -167,10 +167,8 @@ static struct pwm_lookup byt_pwm_lookup[] = {
 
 static void byt_pwm_setup(struct lpss_private_data *pdata)
 {
-	u64 uid;
-
 	/* Only call pwm_add_table for the first PWM controller */
-	if (acpi_dev_uid_to_integer(pdata->adev, &uid) || uid != 1)
+	if (!acpi_dev_uid_match(pdata->adev, "1"))
 		return;
 
 	pwm_add_table(byt_pwm_lookup, ARRAY_SIZE(byt_pwm_lookup));
@@ -218,10 +216,8 @@ static struct pwm_lookup bsw_pwm_lookup[] = {
 
 static void bsw_pwm_setup(struct lpss_private_data *pdata)
 {
-	u64 uid;
-
 	/* Only call pwm_add_table for the first PWM controller */
-	if (acpi_dev_uid_to_integer(pdata->adev, &uid) || uid != 1)
+	if (!acpi_dev_uid_match(pdata->adev, "1"))
 		return;
 
 	pwm_add_table(bsw_pwm_lookup, ARRAY_SIZE(bsw_pwm_lookup));

base-commit: f9c7f9d537da013471e5c7913a33b6489bdeb3cf
-- 
2.17.1

On Thu, Oct 26, 2023 at 02:03:35PM +0530, Raag Jadav wrote:
> Now that we have a standard ACPI helper, we can use acpi_dev_uid_match()
> for matching _UID as per the original logic before commit 2a036e489eb1
> ("ACPI: LPSS: Refactor _UID handling to use acpi_dev_uid_to_integer()"),
> instead of treating it as an integer.
> 
> Signed-off-by: Raag Jadav <raag.jadav@intel.com>
> Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>

The change still looks good to me, however I wonder if we could maybe
improve acpi_dev_uid_match() to support both data types possible for
_UID? This of course is separate patch (unless there are objections).

There is the _Generic() thing and I think that can be used to make

  acpi_dev_uid_match()

which takes either u64 (or maybe even unsigned int) or const char * and
based on that picks the correct implementation. Not sure if that's
possible, did not check but it would allow us to use one function
everywhere instead of acpi_dev_uid_to_integer() and
acpi_dev_uid_match().

On Fri, Oct 27, 2023 at 11:18:55AM +0300, Mika Westerberg wrote:
> On Thu, Oct 26, 2023 at 02:03:35PM +0530, Raag Jadav wrote:
> > Now that we have a standard ACPI helper, we can use acpi_dev_uid_match()
> > for matching _UID as per the original logic before commit 2a036e489eb1
> > ("ACPI: LPSS: Refactor _UID handling to use acpi_dev_uid_to_integer()"),
> > instead of treating it as an integer.
> > 
> > Signed-off-by: Raag Jadav <raag.jadav@intel.com>
> > Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> 
> The change still looks good to me, however I wonder if we could maybe
> improve acpi_dev_uid_match() to support both data types possible for
> _UID? This of course is separate patch (unless there are objections).
> 
> There is the _Generic() thing and I think that can be used to make
> 
>   acpi_dev_uid_match()
> 
> which takes either u64 (or maybe even unsigned int) or const char * and
> based on that picks the correct implementation. Not sure if that's
> possible, did not check but it would allow us to use one function
> everywhere instead of acpi_dev_uid_to_integer() and
> acpi_dev_uid_match().

The way I see it, acpi_dev_uid_to_integer() is useful when drivers want to
parse _UID and store it in their private data, so that it is available for
making various decisions throughout the lifetime of the driver, as opposed
to acpi_dev_uid_match() which is more useful for oneshot comparisons in my
opinion.

So I'm a bit conflicted about merging them into a single helper, unless
ofcourse there is a way to serve both purposes.

However, I do agree that we can improve acpi_dev_uid_match() by treating
uids as integers underneath, instead of doing a raw string comparison.
This would make it more aligned with the spec as suggested by Andy.

Raag