On Wed, Nov 07, 2018 at 09:46:12AM +0100, Michal Simek wrote:

On 01. 11. 18 1:57, Nathan Chancellor wrote:

quoted

Clang warns when one enumerated type is implicitly converted to another:

drivers/pinctrl/pinctrl-zynq.c:985:18: warning: implicit conversion from
enumeration type 'enum zynq_pin_config_param' to different enumeration
type 'enum pin_config_param' [-Wenum-conversion]
        {"io-standard", PIN_CONFIG_IOSTANDARD, zynq_iostd_lvcmos18},
        ~               ^~~~~~~~~~~~~~~~~~~~~
drivers/pinctrl/pinctrl-zynq.c:990:16: warning: implicit conversion from
enumeration type 'enum zynq_pin_config_param' to different enumeration
type 'enum pin_config_param' [-Wenum-conversion]
        = { PCONFDUMP(PIN_CONFIG_IOSTANDARD, "IO-standard", NULL, true),
            ~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./include/linux/pinctrl/pinconf-generic.h:163:11: note: expanded from
macro 'PCONFDUMP'
        .param = a, .display = b, .format = c, .has_arg = d     \
                 ^
2 warnings generated.

This is interesting. I have never tried to use llvm for building the
kernel. Do you have any description how this can be done?

Depending on what version of Clang you have access to, it is usually just as
simple as running 'make ARCH=arm CC=clang CROSS_COMPILE=arm-linux-gnueabi-'.

Clang 7.0+ is recommended but 6.0 might work too.

quoted

It is expected that pinctrl drivers can extend pin_config_param because
of the gap between PIN_CONFIG_END and PIN_CONFIG_MAX so this conversion
isn't an issue. Most drivers that take advantage of this define the
PIN_CONFIG variables as constants, rather than enumerated values. Do the
same thing here so that Clang no longer warns.

Signed-off-by: Nathan Chancellor <redacted>
---
 drivers/pinctrl/pinctrl-zynq.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/pinctrl/pinctrl-zynq.c b/drivers/pinctrl/pinctrl-zynq.c
index a0daf27042bd..57046c221756 100644
--- a/drivers/pinctrl/pinctrl-zynq.c
+++ b/drivers/pinctrl/pinctrl-zynq.c

@@ -972,14 +972,11 @@ enum zynq_io_standards {
 };
 
 /**
- * enum zynq_pin_config_param - possible pin configuration parameters

This is wrong. kernel-doc is reporting issue with it.

drivers/pinctrl/pinctrl-zynq.c:975: warning: Cannot understand  *
@PIN_CONFIG_IOSTANDARD: if the pin can select an IO standard, the
argument to
 on line 975 - I thought it was a doc line
1 warnings

Ah yes, I forgot to send a v2 of this patch when someone pointed out
this problem in a different patch. I'll send that now, thanks for the
review!

quoted

  * @PIN_CONFIG_IOSTANDARD: if the pin can select an IO standard, the argument to
  *	this parameter (on a custom format) tells the driver which alternative
  *	IO standard to use.
  */
-enum zynq_pin_config_param {
-	PIN_CONFIG_IOSTANDARD = PIN_CONFIG_END + 1,
-};
+#define PIN_CONFIG_IOSTANDARD		(PIN_CONFIG_END + 1)
 
 static const struct pinconf_generic_params zynq_dt_params[] = {
 	{"io-standard", PIN_CONFIG_IOSTANDARD, zynq_iostd_lvcmos18},

This change is fine.

Thanks,
Michal